Dissertation: "Regaining Control"
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Final Semester Dissertation for B.FTech Degree (Bachelor in Fashion Technology), National Institute of Fashion Technology, 2010.

Final Semester Dissertation for B.FTech Degree (Bachelor in Fashion Technology), National Institute of Fashion Technology, 2010.

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Dissertation: "Regaining Control" Dissertation: "Regaining Control" Document Transcript

  • REGAINING CONTROL – DRUM-BUFFER-ROPE IN MADE-TO-ORDER APPAREL MANUFACTURINGARUSH DIXIT & VASHISTHA IYERDepartment of Fashion TechnologyNational Institute of Fashion Technology, GandhinagarMay, 2010
  • REGAINING CONTROL – DRUM-BUFFER-ROPE IN MADE-TO-ORDER APPAREL MANUFACTURINGA dissertation submitted in partial Fulfillmentof the requirement for the award of DegreeinBachelor of Fashion Technology (Apparel Production)Submitted ByARUSH DIXIT & VASHISTHA IYERUnder the Guidance ofMR. MANOJ TIWARIDepartment of Fashion TechnologyNational Institute of Fashion Technology, GandhinagarMay, 2010
  • IndexAbstract............................................................................................................................................ iCertificate........................................................................................................................................iiAcknowledgements........................................................................................................................iiiList of Tables ................................................................................................................................. ivList of Figures................................................................................................................................. v01. Introduction............................................................................................................................... 11.1. Objectives............................................................................................................................. 402. Review of Literature ................................................................................................................. 52.1 Production Concepts & Applications.................................................................................... 62.2. Theory of Constraints......................................................................................................... 182.3. V/A/T Analysis & Synchronous Manufacturing................................................................ 202.4. Drum-Buffer-Rope Scheduling.......................................................................................... 232.2 List of References................................................................................................................ 2803. Methodology........................................................................................................................... 293.1. Scope of Research .............................................................................................................. 303.2. Assumptions....................................................................................................................... 303.3. Constraints.......................................................................................................................... 303.3.1. Identifying the Constraint............................................................................................ 313.3.2. V/A/T and 5 Why Analysis ......................................................................................... 313.3.3. Design of Constraint.................................................................................................... 323.4. Applying Drum-Buffer-Rope............................................................................................. 333.4.1. Establishing Time Buffers........................................................................................... 343.4.2. Creating a Drum Schedule........................................................................................... 343.4.3. Buffer Management..................................................................................................... 353.4.4. Comparison of Existing & Proposed Systems............................................................. 3504. Constraints .............................................................................................................................. 374.1.  Identifying  the  System’s  Constraint................................................................................... 404.2.  Designing  the  System’s  Constraint .................................................................................... 454.3.  Exploiting  the  System’s  Constraint.................................................................................... 46
  • 05. Drum-Buffer-Rope.................................................................................................................. 505.1. The Drum ........................................................................................................................... 515.2. The Buffer .......................................................................................................................... 525.3. The Rope ............................................................................................................................ 555.4. Drum-Buffer-Rope Schedule ............................................................................................. 565.5. Buffer Management............................................................................................................ 615.5.1 Local Control – Buffer status ....................................................................................... 635.5.2. Global Feedback - Buffer Hole ................................................................................... 645.5.3. Global Feedback –Reason code analysis..................................................................... 655.5.4 Local Measurements..................................................................................................... 6606. Results..................................................................................................................................... 696.1. Planned v/s Actual.............................................................................................................. 706.2. The Drum-Buffer-Rope Schedule...................................................................................... 726.3. New v/s Old........................................................................................................................ 7407. Limitations and Scope of Further Study................................................................................. 757.1. Limitations ......................................................................................................................... 767.2. Scope for Further Study ..................................................................................................... 7708. Conclusion .............................................................................................................................. 798.1. Recommendations.............................................................................................................. 8209. Bibliography ........................................................................................................................... 84Mabin  J.  Victoria  &  Steven  J.  Balderstone  “The  world  of  the  theory  of  constraints: a review ofthe  international  literature”  CRC Press (2000)............................................................................. 85Appendices.................................................................................................................................... 87Appendix A ................................................................................................................................ viAppendix B ...............................................................................................................................viiAppendix C.1 ...........................................................................................................................viiiAppendix C.2 ............................................................................................................................. ixAppendix C.3 .............................................................................................................................. xAppendix C.4 ............................................................................................................................. xiAppendix D ...............................................................................................................................xiiAppendix E...............................................................................................................................xiii
  • Appendix F............................................................................................................................... xivAppendix G.1 ............................................................................................................................ xvAppendix G.2 ........................................................................................................................... xviAppendix G.3 ..........................................................................................................................xviiAppendix G.4 .........................................................................................................................xviiiAppendix G.5 ........................................................................................................................... xixAppendix G.6 ............................................................................................................................ xxAppendix G.7 ........................................................................................................................... xxiAppendix G.8 ..........................................................................................................................xxiiAppendix G.9 .........................................................................................................................xxiiiAppendix H ............................................................................................................................ xxivAppendix I............................................................................................................................... xxvAppendix J.1........................................................................................................................... xxviAppendix J.2..........................................................................................................................xxviiAppendix K ..........................................................................................................................xxviiiAnnexures .................................................................................................................................. xxixAnnexure 1................................................................................................................................xxx
  • iAbstractApparel companies are continuously exploring different philosophies to improve theiroperations. Amongst others, Theory of Constraints provides the simplest solution for productionin the form of Drum-Buffer-Rope scheduling, an application which does not require large sets ofdata, extensive worker training or lower level buy-in. This paper illustrates how a drum-buffer-rope application can be designed and implemented in a high-mix/low-volume made-to-orderapparel manufacturing environment. It addresses the various issues that apparel manufacturerscould face when beginning to implement a Theory of Constraints application. Theimplementation was carried out in an apparel export house in Jaipur, Rajasthan and showedthat drum-buffer-rope can be successfully applied to even small and medium sized companiesenabling them to achieve dramatic improvements in due-date performance and substantialreduction in lead times and inventories. Of the various benefits that Drum-Buffer-Rope canprovide, the most immediate one is a production schedule which actually works despite thecommon culprits such as unreliable vendors, absenteeism, machine breakdowns, absence ofaccurate data, unreliable processes and quality problems. Such a high performing scheduleleads to a high performing and stable system. This stability must be used as the cornerstone tokick start a process of ongoing improvement in the pursuit of operational excellence.
  • iiCertificate“This  is  to  certify  that  this  Project  Report  titled  “Regaining Control – Drum-Buffer-Rope inMade-to-Order  Apparel  Manufacturing” is based on our, Arush Dixit’s &  Vashishtha  Iyer’soriginal research work, conducted under the guidance of Mr. Manoj Tiwari towards partialfulfillment of   the   requirement   for   award   of   the   Bachelor’s   Degree   in   Fashion   Technology  (Apparel Production), of the National Institute of Fashion Technology, Gandhinagar.No part of this work has been copied from any other source. Material, wherever borrowedhas been duly acknowledged.Arush Dixit Vashistha Iyer
  • iiiAcknowledgementsWe are extremely grateful to National Institute of Fashion Technology for making thisexercise in effect with the curriculum. The project would not have been completed without thetimely efforts and involvement of our mentor Mr. Manoj Tiwari (Asst. Professor, DFT) and Ms.Amisha Mehta (CC-DFT). Their guidance is an indispensable part of this research work.We express our heartfelt gratitude to Mr.Rajiv Dewan (CEO) and Mr. Rakesh Dewan(Director),  Ma’Am Arts, Jaipur for their candid didactics on the apparel export business and forallowing us to pursue our graduation project with their company.Mr. Varun Mishra (General Manager - Production) deserves a special mention for providingthe required support during the implementation phase of the project and for those endlessdebates about the project and related concepts. We are also thankful to the staff of Ma’Am Artsfor their support and coordination.Last but not the least we thank our parents and friends for being a constant source of supportand inspiration.
  • ivList of TablesTable 4.1 - Style Produced between 8thMarch, 2010 and 7thApril, 2010.................................... 42Table 4.2 - Types of Packing........................................................................................................ 48Table 4.3 - Illustration of production within the drum ................................................................ 49Table 5.1 A - Lead time from Material Release to Sewing for Dyed Products............................ 53Table 5.1 B - Lead time from Material Release to Sewing for Printed Products ......................... 53Table 5.2 - Production Buffer Size ............................................................................................... 54Table 5.3 A - Details of orders executed on the Drum................................................................. 56Table 5.3 B - Due dates of orders executed on the Drum............................................................. 56Table 5.4 - Estimating Work Content........................................................................................... 57Table 5.5 - Detail plan for Sheet No. 1732 A and 1732 B fed to Drum I consecutively.............. 59Table 5.6 - Drum Schedule........................................................................................................... 60Table 5.7 - Material Release Schedule ......................................................................................... 61Table 5.8 - Reason Code Analysis................................................................................................ 66Table 5.9 - Severity....................................................................................................................... 67Table 5.10 - Daily Severity Chart................................................................................................. 68Table 6.1 - Planned v/s Actual at Drum 1 on 15thApril ............................................................... 70Table 6.2 - Planned vs Actual comparison for packed output at Drum 1..................................... 71Table 6.3 - Planned vs Actual comparison for packed output at Drum 2..................................... 72Table 6.4 - Progress of Order scheduled by Drum-Buffer-Rope (Sundays are excluded) ........... 73Table 6.5 - Performance Comparison ............................................................................................74
  • vList of FiguresFigure 2.1 - Relationship between management time required and the time buffer size.............. 17Figure 4.1 - Flowchart  of  Processes  at  MA’AM  Arts,  Jaipur....................................................... 41Figure 4.2 - Shifting Bottlenecks.................................................................................................. 43Figure 5.1 - Drum and Buffer ....................................................................................................... 54Figure 5.2 - Effects of Choking Material Release ....................................................................... 55Figure 5.3 - Determining Drum Start and Material Release......................................................... 58Figure 5.4 - Zoning of Buffers...................................................................................................... 62Figure 5.5A - Buffer holes in production buffer for dyed products.............................................. 64Figure 5.5B - Buffer holes in production buffer for printed products .......................................... 65Figure 5.6 - Buffer Exhaustion ..................................................................................................... 66
  • 101. Introduction
  • 2“A   truly   prosperous   time   is   when   the   largest   numbers   of   people   are   getting   all   they   can  legitimately eat and wear, and are in every sense of the word comfortable. It is the degree of thecomfort of the people at large--not the size of the manufacturers bank balance--that evidencesprosperity. The function of the manufacturer is to contribute to this comfort. He is an instrumentof society and he can serve society only as he manages his enterprises so as to turn over to thepublic an increasingly better product at an ever-decreasing price, and at the same time to pay toall those who have a hand in his business an ever-increasing wage, based upon the work they do.In this way and in this way alone can a manufacturer or any one in business justify hisexistence.”  – Henry Ford, My Life and WorkThe business of fashion in the 21stcentury has evolved into a complex web with the adventof globalization transcending it beyond physical barriers between markets and manufacturers.Increased fashion cycles have led to buyers demanding shorter lead times and exceptional duedate performance from their suppliers. While certain mass producers of apparel in India operateworld class manufacturing plants with some manufacturers even successfully running Lean andSix Sigma philosophies, the majority of apparel manufacturers remain small to medium scaleindustries with not enough management talent to execute advanced production systems. Plaguedwith seasonal demand, high labor turnover and arcane systems, it seems they thrive only on lowlabor costs. With even labor costs going up and the increasing availability of higher payingalternative low skill jobs, these manufacturers must find a way to manage their operationswithout heaps of inventory, uncontrollable overtime, quality problems and low due dateperformance.Solutions to these problems have been available since many decades. Taiichi Ohno presentedhis Toyota Production Systems based on Just-in-Time concepts in as early as 1988. This has
  • 3evolved into a management philosophy called Lean Manufacturing and is being actively pursuedby competent apparel manufacturers today. Lean represents a utopian system where no wastesshould   exist.   From   an   operational   point   of   view,   it’s   the   ultimate   objective.   But   consider   the  plight of small and medium scale made-to-order apparel manufacturers. A lean implementationrequires stability in the system, buy-in at the floor level and a culture of continuousimprovement. Trying to implement Lean concepts in such volatile environments where each andevery order is hot, red-hot or drop-everything-else-and-make-this-urgently hot is certainly not apragmatic solution. What is required is a system which can provide this necessary condition ofstability – An operating mechanism which can shorten lead time, reduce inventory and deliverexceptional due-date performance. In fact, such a mechanism does exist. It is the Theory ofConstraints Drum-Buffer-Rope Scheduling system. This paper explores the applicability of thissystem a high-mix/low-volume made-to-order apparel manufacturing environment.Theory  of  Constraints,  introduced  by  Dr.  Eliyhu  M.  Goldratt  in  his  book  “The  Goal”  in  1984,  is a management philosophy which advocates a systemic view of the business. It considers thesystem as a chain whose strength is governed by its weakest link, the constraint. It implores theelimination of decision making based on local efficiencies and encourages improving the globaloptimum by exploiting the constraint. Drum-Buffer-Rope is the logistical application of Theoryof Constraints – a scheduling system providing planning and controlling methods. Drum-Buffer-Rope is a relatively simple system and one of its biggest advantages is that it does not requirebuy-in at the floor level. Only a higher level buy-in is required for successful implementation.Enough literature also exist which showcase documented evidence of successful Theory ofConstraints implementation with fast and significant positive results.
  • 4This paper explores the applicability of Drum-Buffer-Rope to objectively conclude if it is infact a practical solution which can deliver high due-date performance even in volatileenvironments. It is limited to products which do not require any processing between sewing,finishing & packing of garments.1.1. Objectives Identify the system constraint & develop an exploitation strategy with minimalchanges in current working. Implement drum-buffer-rope scheduling Design a constructive control mechanism to monitor drum-buffer-ropeThe stability that the system described in this paper can deliver should be used as acornerstone to drive a process of ongoing improvement which not only aims to create moremoney for the manufacturer but also to develop and evolve production systems while providingemployees with better working conditions and higher wages. Operational stability is the firsthurdle stopping manufacturers from looking beyond seasonal profits and must be addressedimmediately.
  • 502. Review of Literature
  • 6The manufacturing of apparel has evolved to include the application of various productionsystems depending on the nature of business and type of product. In the pursuit of runningexcellent operations, organizations have implemented various production systems and adapteddifferent philosophies with varying levels of success and failure. Most of such efforts have beendriven by a primary focus on reducing costs through an emphasis on increasing localimprovements. However, a global focus on improving the overall system is required based on alogical operating principle with supporting mechanisms to govern local improvements. Beforelocal improvements can be effectively made, the system must be stabilized on a reliableoperating mechanism. The Theory of Constraints Drum-Buffer-Rope Scheduling applied as theoperating principle to design the overall production system can provide such a system along withthe power of focus. Instead of improving many areas simultaneously, improvement efforts can belogically directed to the problem areas that affect the system the most. Once the area of focus isidentified, local improvements based on Lean tools and principles can lead to effective andmeaningful results. The following review illustrates the evolution of assembly lines and pull-systems highlighting their underlying principles and examines literature on the Theory ofConstraints, Drum-Buffer-Rope scheduling, V-A-T plant analysis and the fundamentals of Leanmanufacturing.2.1 Production Concepts & ApplicationsThe perception of apparel manufacturing is often limited to its certain functions such asMerchandising, Cutting, Sewing and Finishing. Within this context, the larger picture is oftenmissed. Made-to-Order apparel manufacturing must be seen as a whole system and not just acollection   of   individual   departments   and   it’s   most   important   measure   should   be   Due-DatePerformance. The following excerpts highlight the principles governing manufacturing systems
  • 7and lead to the rationale of why a Theory of Constraints Drum-Buffer-Rope application can bevery effective in improving the Due-Date Performance of such systems.“The  manufacturing  industry  has  been  shaped  by  two  great  thinkers,  Henry  Ford  and  Taiichi  Ohno. Ford revolutionized mass production by introducing the flow lines. Ohno took Ford’s  ideas to the next level in his Toyota Production System (TPS), a system that forced the entireindustry  to  change  its  grasp  of  inventory  from  an  asset  to  a  liability.  Ford’s  starting  point  was  that the key for effective production is to concentrate on improving the overall flow of productsthrough the operations. If transportation were perfect and an even flow of materials could beassured, it would not be necessary to carry any stock whatsoever. The carloads of raw materialswould arrive on schedule and in the planned order and amounts, and go from the railway carsinto production. That would save a great deal of money, for it would give a very rapid turnoverand  thus  decrease  the  amount  of  money  tied  up  in  materials.”“Ford’s   efforts   to   improve   flow were so successful that, by 1926, the lead time frommining the iron ore to having a completed car, composed of more than 5,000 parts on the trainready for delivery, was 81 hours. Eighty years later, no car manufacturer in the world has beenable to achieve,  or  even  come  close,  to  such  a  short  lead  time.”“Flow   means   that   inventories   in   the   operation   are   moving.   When   inventory   is   not  moving, inventory accumulates. Accumulation of inventory takes up space. Therefore, anintuitive way to achieve better flow is to limit the space allowed for inventory to accumulate. Toachieve better flow, Ford limited the space allotted for work-in-process between each two workcenters. That is the essence of the flow lines, as can be verified by the fact that the first flow lines
  • 8didn’t  have  any  mechanical  means,  like  conveyers,  to  move  inventory  from  one  work  center  to  another.”  “The   daring   nature   of   Ford’s   method   is   revealed   when   one   realizes   that   a   direct  consequence of limiting the space is that when the allotted space is full, the workers feeding itmust stop producing. Therefore, in order to achieve flow, Ford had to abolish local efficiencies.In other words, flow lines are flying in the face of conventional wisdom; the convention that, tobe effective, every worker and every work center have to be busy 100% of the time. One mightthink that preventing resources from working continuously will decrease throughput (output) ofthe operation. That undesirable effect might have been the result if Ford would have beensatisfied with just limiting the space. But, there is another effect that stems from restricting theaccumulation of inventory. It makes it very visible to spot the real problems that jeopardize theflow – when one work center in a line stops producing for more than a short while, soon thewhole line stops. Ford took advantage of the resulting clear visibility to better balance the flowby addressing and eliminating the apparent stoppages. The end result of abolishing localefficiencies and balancing the flow is a substantial increase in throughput. Henry Ford achievedthe  highest  throughput  per  worker  of  any  car  manufacturing  company  of  his  time.”  01.ALike   Ford,   Ohno’s   primary   objective   was   improving   flow   – decreasing lead time – asindicated in his response to the question about what Toyota is doing:“All  we  are  doing  is  looking  at  the  time  line  from  the  moment  the  customer  gives  us  an  order  to  the  point  when  we  collect  the  cash.  And  we  are  reducing  that  time  line…”Ohno established the Toyota Production System to achieve flow by focusing on removingwastes. In his works, Ohno gives full credit for the underlying concepts to Ford. The original
  • 9emphasis on the importance of identifying and removing wastes was stated by Ford in a chaptertitled  “Learning  from Waste”  02–“Conserving   our   natural   resources   by   withdrawing   them   from   use   is   not   a   service   to   the  community. That is holding to the old theory that a thing is more important than a man. Ournatural resources are ample for all our present needs. We do not have to bother about them asresources.  What  we  do  have  to  bother  about  is  the  waste  of  human  labor.”“Take  a  vein  of  coal  in  a  mine.  As  long  as  it  remains  in  the  mine,  it’s  of  no  importance,  but when a chunk of that coal has been mined and set down in Detroit, it becomes a thing ofimportance, because then it represents a certain amount of the labor of men used in its miningand transportation. If we waste that bit of coal - which is another way of saying if we do not putit to its full value — then we waste the time and energy of men. A man cannot be paid much forproducing  something  which  is  to  be  wasted.”“My  theory  of  waste  goes  back  of  the  thing  itself  into  the  labor  of  producing  it.  We  want  to  get full value out of labor so that we may be able to pay it full value. It is use — not conservation— that interests us. We want to use material to its utmost in order that the time of men may notbe lost. Material costs mean nothing. It is of no account until it comes into the hands ofmanagement.”“Saving material because it is material, and saving material because it represents labor mightseem to amount to the same thing. But the approach makes a deal of difference. We will usematerial more carefully if we think of it as labor. For instance, we will not so lightly wastematerial simply because we can reclaim it — for salvage involves labor. The ideal situation is tohave  nothing  to  salvage.”
  • 10“We  have  a  large  salvage  department,  which  apparently  earns  for  us  twenty  or  more  million  dollars a year. But as that department grew and became more important and more strikinglyvaluable, we began to ask ourselves: Why should we have so much to salvage? Are we notgiving  more  attention  to  reclaiming  than  to  not  wasting?”“And  with  that  thought  in  mind,  we  set  out  to examine all our processes. A little of what wedo in the way of saving manpower by extending machinery has already been told, and what weare doing with coal, wood, power and transportation will be told in later chapters. This has to doonly with what was waste. Our studies and investigations up to date have resulted in the savingof 80,000,000 pounds of steel a year that formerly went into scrap and had to be reworked withthe expenditure of labor. This amounts to about three million dollars a year, or, to put it in abetter way, to the unnecessary labor on our scale of wages of upward of two thousand men. Andall of that saving was accomplished so simply that our present wonder is why we did not do itbefore.”Ohno expanded this understanding to modern manufacturing and identified seven wastes,whose elimination forms the backbone of Lean thinking. Ohno introduced these wastes in thesection  titled  “Complete  Analysis  of  Waste”  03-“Modem  industry  seems  stuck  in  this  way  of  thinking.  A  person  in  business  may feel uneasyabout survival in this competitive society without keeping some inventories of raw materials,work-in-process,  and  products.”“This  type  of  hoarding,  however,  is  no  longer  practical.  Industrial  society  must  develop  the  courage, or rather the common sense, to procure only what is needed when it is needed and in theamount  needed.”
  • 11“This  requires  what  I  call  a  revolution  in  consciousness,  a  change  of  attitude  and  viewpoint  by business people. In a period of slow growth, holding a large inventory causes the waste ofoverproduction. It also leads to an inventory of defectives, which is a serious business loss. Wemust understand these situations in-depth  before  we  can  achieve  a  revolution  in  consciousness.”“When  thinking  about  the  absolute  elimination of waste, keep the following two points inmind”:1. Improving efficiency makes sense only when it is tied to cost reduction. To achievethis, we have to start producing only the things we need using minimum manpower.2. Look at the efficiency of each operator and of each line. Then look at the operators asa group, and then at the efficiency of the entire plant (all the lines). Efficiency mustbe improved at each step and1 at the same time, for the plant as a whole.“Let’s  say,  for  instance,  one  production line has 10 workers and makes 100 products per day.This means the line capacity is 100 pieces per day and the productivity per person is 10 piecesper day. Observing the line and workers in further detail, however, we notice overproduction,workers waiting,  and  other  unnecessary  movements  depending  on  the  time  of  day.”“Suppose  we  improved  the  situation  and  reduced  manpower  by  two  workers.  The  fact  that  8  workers could produce 100 pieces daily suggests that we can make 125 pieces a day, increasingefficiency without reducing manpower. Actually, however, the capacity to make 125 pieces aday  existed  before  but  it  was  being  wasted  in  the  form  of  unnecessary  work  and  overproduction.”
  • 12“This  means  that  if  we  regard  only  work  that  is  needed  as  real  work  and  define the rest aswaste, the following equation holds true whether considering individual workers or the entireline:  Present  Capacity  =  Work  +  Waste”“True  efficiency  improvement  comes  when  we  produce  zero  waste  and  bring  the  percentage  of work to 100 percent. Since, in the Toyota production system, we must make only the amountneeded,  manpower  must  be  reduced  to  trim  excess  capacity  and  match  the  needed  quantity.”“The   preliminary   step   toward   application   of   the   Toyota   production   system   is   to   identify  wastes  completely”:  1. Waste of overproduction2. Waste of time on hand (waiting)3. Waste in transportation4. Waste of processing itself5. Waste of stock on hand (inventory)6. Waste of movement7. Waste of making defective products“Eliminating   these   wastes   completely   can improve the operating efficiency by a largemargin. To do this, we must make only the quantity needed, thereby releasing extra manpower.The Toyota production system clearly reveals excess manpower. Because of this, some laborunion people have been suspicious of it as a means of laying off workers. But that is not theidea.”
  • 13“Management’s   responsibility   is   to   identify   excess   manpower   and   utilize   it   effectively.  Hiring people when business is good and production is high just to lay them off or recruitingearly retirees when recession hits are bad practices. Managers should use them with care. On theother  hand,  eliminating  wasteful  and  meaningless  jobs  enhances  the  value  of  work  for  workers.”“Ohno  was  fully  aware  that  there  were  too  many  things  that  can  be improved, that without away to focus the process improvement efforts it would take too long to balance the flow. TheKanban system provided him such a way. Between each two work centers and for eachcomponent separately, the accumulation of inventory is limited by setting a certain number ofcontainers and the number of units per container. These containers, like every container in everyindustry, also contain the relevant paperwork. But, one page of the paperwork – usually a card(kanban in Japanese) – a page that specifies only the component code name and the number ofunits per container, is treated in an unconventional way. When the succeeding work centerwithdraws a container for further processing that card is not moved with the container, rather it ispassed back to the preceding work center. This is the notification to that work center that acontainer was withdrawn, that the allotted inventory is not full. Only in that case is the precedingwork center allowed to produce (one container of parts specified by the card). In essence theKanban system directs each work center when and what to produce but, more importantly, itdirects when not to produce. No card – no production. The Kanban system is the practicalmechanism that guides the operation when not to produce prevents overproduction. Ohnosucceeded   to   expand   Ford’s   concepts   by   changing   the   base   of   the   mechanism   from   space   to  inventory.”  01.BThe underlying concepts adopted by Ford and Ohno stated as the concepts of supply chains -
  • 141. Improving flow (or equivalently lead time) is a primary objective of operations.2. This primary objective should be translated into a practical mechanism that guides theoperation when not to produce (prevents overproduction). Ford used space; Ohnoused inventory.3. Local efficiencies must be abolished.4. A focusing process to balance flow must be in place. Ford used direct observation.Ohno used the gradual reduction of the number of containers and then gradualreduction of parts per container.The Limitations of TPS -1. TPS is restricted to relatively stable environments,2. Most environments suffer from instability, and3. Relatively unstable environments have much more to gain from better flow than evenstable environments.“The   most   intuitive   base   for   the   mechanism   to   restrict over-production is not space orinventory but time – if one wants to prevent production ahead of time one should not release thematerial ahead of time. Using time as the base is not only more intuitive and, therefore, moreeasily accepted by the shop floor, it has an advantage that makes it suitable for unstableenvironments – it is much less sensitive to disruptions in flow. The robustness of the time-basedmechanism stems from the fact that it directly restricts the overall amount of work in the systemrather than doing it through restricting the amount of work between each two work centers. Inflow lines or Kanban-based systems the allotted inventories between work centers is restricted tothe bare minimum (usually corresponding to much less than one hour of work). Therefore, when
  • 15a work center is down for more than a short while the succeeding work centers are almostimmediately   starved   for   work   and   the   preceding   work   centers   are   “blocked”   from   working.  When, for any of the work centers, the accumulated time consumed by starvation and blockage ismore than the excess capacity of that work center, the throughput of the company is reduced. Thesensitivity of flow lines and Kanban-based systems stems from the fact that a disruption thatoccurs in one work center consumes capacity also from the upstream and downstream workcenters – a  phenomenon  that  (almost)  doesn’t  exist  for  the  time-based systems since the work,once released to the floor is not artificially restrained. The time based application of the supplychains concept is the Theory of Constraints Drum-Buffer-Rope  system.”  01.C“Many   claims   were   made   regarding   the   benefits   of   TOC.   These   included:   increased  Throughput (i.e., Revenue—Totally Variable Costs), reduced inventories, and reduced lead-times, which in turn would lead to higher sales, and improvements in profits, quality, andcustomer satisfaction. We felt it would be useful to collect together and analyze the actualreported data on the benefits of TOC, to verify or disprove these claims. The literature searchidentified over 100 case studies or vignettes that contained information on the results ofapplications of TOC. Not all of these provided quantitative data on the results of applying TOC.In total, we were able to collect quantitative data on the application of TOC to 82 differentcompanies. The types of organizations covered by these cases varied from giant multi-nationalcorporations and industry leaders like Boeing and General Motors, to military organizations likethe U.S. Air Force to small  town  bakeries.”  04The results of the analysis of reported changes in operational and financial performance,resulting from the application of TOC, are summarized below:
  • 16 Lead Time Mean Reduction – 70% Inventory Level Mean Reduction – 49% Revenue/Throughput/Profit Mean Increase – 76%The export oriented apparel manufacturing industry works in a make-to-order environment.A classical measure of the performance of systems in such an environment is due-dateperformance. Previous literature has demonstrated that due-date performance can be improvedby effective management of order release, working priorities, and bottlenecks.“Our  experimental  study  examined  why  high  due-date performance is difficult to achieve.Thirty teams participated in the first experiment and five teams in the second experiment(involving a total of 245 people). Our results support the notion that in most cases, variability isnot the root cause of poor due-date performance. Poor due-date performance is caused by themode of managing operations,  including  the  following  phenomena”  05:1. Over-promising, or setting order due dates that fail to consider the planned load of theconstraint;2. Not choking the order release, which results in too many orders on the shop floor dueto excessively early release, a situation that masks priorities, promotes local optimalbehavior, prolongs lead time, and significantly disrupts due-date performance;3. Failure to manage priorities, resulting in hectic priorities that create chaos on the floorand lead to late orders.“Based  on  our  findings,  due-date performance improvement programs should first focus onimproving the management of production planning and execution, instead of reducingvariability.”  05
  • 17Drum-Buffer-Rope, a Theory of Constraints planning & scheduling solution is a time-basedapplication of the supply chains concept. The fundamental assumption is that within any plantthere is one or a limited number of scarce resources which control the overall output of thatplant.  This  is  the  “drum”  which  sets the pace of all other resources. In order to maximize theoutput of the system, planning and execution behaviors are focused on exploiting the drum,protecting   it   against   disruption   through   the   use   of   “time   buffers”   and   synchronizing   or  subordinating all other resources and decisions to the activity of the drum through a mechanismthat  is  akin  to  a  “rope”.  06Figure 2.1 Relationship between management time required and the time buffer size. 01.D
  • 182.2. Theory of ConstraintsIt  has  been  said;;  “Tell  me  how  you  will  measure  me,  and  I  will  tell  you  how  I  will  behave”  07.AThe whole internal business performance measurement system is based upon localoptimization, either in the form of departmental utilization/efficiency measures or asdepartmental cost/profit performance measures - or both. It takes some conscious effort torealize that the formalization of local efficiency measures through the activities of scientificmanagement is only about 100 years old. 08Its assumed that the total performance of the systemis the sum of all the local performances. In fact it is so common that it is not even given muchthought. This approach then is the reductionist/local optima approach; departmental cost orefficiency is just a symptom or an output of this method. 09“Living  systems  have  integrity. Their character depends on the whole. The same is true fororganizations; to understand the most challenging managerial issues require seeing the wholesystem  that  generates  issues.”  10It should be known what the system is that one is dealing with,where does it start, and where does it end. It should be known what the system exists for, andhow to measure progress towards the reason for its existence. Scheinkopf expresses this as 11:1. Define the system and its purpose.2. Determine  the  system’s  fundamental  measurements.The organization in fact defines the measurements rather than the other way around – themeasurements define the organization. Margaret Wheatley is more articulate. She argues that intoo   many   organizations   “…   the   measures   define   what   is   meaningful   rather   than   letting   thegreater meaning of the work define the measures. As the focus narrows, people disconnect fromany  larger  purpose  and  only  do  what  is  required  of  them.”  10
  • 19The fundamental measures for a system must be determined and then ensured thatperformance measures are subordinated to these fundamental measures. “Not   just   any  measurements, but measurements that will enable us to judge the impact of a local decision onthe  global  goal.”  07.B“Measurements  are  a  direct  result  of  the  chosen  goal. There is no way that we can select aset  of  measurements  before  the  goal  is  defined.” The measurements should enable the judgmentwhether a local decision has an impact on the global goal. 07.CIn a commercial organization the fundamental measures are defined by the followingquestions 07.D:1. How much money is generated by the company?2. How much money is captured by the company?3. How much money is spent to operate it?Goldratt calls these 3 measures; Throughput, Inventory, and Operating Expense. These areoften shortened to T, I, and OE and are defined as follows 07.E:1. Throughput is the rate at which the system generates money through sales.2. Inventory is all the money that the system invests in purchasing things which it intends tosell.3. Operating expense is all the money the system spends in order to turn inventory intothroughput.
  • 202.3. V/A/T Analysis & Synchronous ManufacturingSerial processes where there are dependencies between one step and another are a relativelynew phenomenon. Prior to the industrial revolution such organizations did not exist. Since thebeginning of industrial revolution many have done little more than become larger and morecomplicated as they take advantage of economies of scale and economies of scope. 08In a process where similar machines, or people who are doing similar operations, are groupedtogether, work moves in a sequence between these specialist areas, sometimes flowing back theway it came to a previous area before continuing on in the process. This layout is known as a“job  shop.” A simple example might be a small engineering firm. Each job in the process couldbe unique or it could be a repetition of a standard design. Each job could consist of single unit ora batch of many units. 09At  the  other  end  of  the  scale  from  the  job  shop  is  a  “flow  shop.” Here machinery or peopleare sequenced throughout the plant in the order that most work will require. Again the workmight be unique or a repetition of a standard design. Each job could consist of a single unit or abatch of many units. 09Furniture companies that produce for the retail trade are usually a flow shop. Tool bitmanufacturers are another example. So too are electronics and automotive, however, as thediversity of products decreases and the batch size increases the flow in parts of these flow shopsbecomes more and more continuous. Ultimately these parts may become a dedicated flow shop– one flow or process for one product or product family. 09So,  why  can’t  these  flow  shops become truly continuous, like a pulp and paper plant, or apetrochemical process? The answer is that the items in the process are discrete, made of
  • 21individual parts, rather than non-discrete like a liquid or a crushed ore. In fact many of the trulycontinuous industries are in the primary or extractive industries – pulp and paper, petrochemical,and dairy. Most of these industries benefit from economies of scale and are capital intensivewith a concomitant reduction or replacement of labor. 09Within the discrete product job shop and flow shops there are 3 basic topologies whichdescribe the flow of material within the process. V/A/T plant classification was developedprimarily by Eli Goldratt. Around 1980, while running a consulting organization called CreativeOutput, Goldratt noticed that manufacturing plants in very different industries seemed to havesimilar characteristics and problems. From this experience he developed the V/A/T classificationsystem. 12Product flow diagrams are used to determine the structure of a plant. Three specificcategories of points are of special interest in product flow diagrams: divergence points,convergent assembly points, and divergent assembly points. Divergence points are steps in theproduct flow at which material may be transformed into two or more distinctly differentmaterials. Convergent assembly points are points at which two or more component parts areassembled to form a single parent item. Divergent assembly points occur when a number ofcommon component parts may be combined or assembled in a variety of ways to form a largenumber of possible parent items. The product flow diagram of a specific manufacturingenvironment may include divergence points, convergent assembly points, and divergentassembly points. However, one of these three categories will usually dominate. This observationled to the development of three basic plant classification categories: V-plants, A-plants and T-plants. 13
  • 22Product flow diagrams for V-plants are characterized by divergence points throughout theproduction process. In such plants, a single piece of material can be increasingly transformed ateach divergence point into a very large number of distinctly different end items. The generalshape of the product flow diagram resembles the letter "V," hence the designation V-plant. 13A-plants are characterized by convergent assembly points throughout the process. In suchplants, a large number of purchased or fabricated component parts and materials are combined toform subassemblies that are used to build unique end products. Several levels of subassembliesare typically necessary before final assembly can be performed. The typical product flowdiagram for a plant exhibiting this basic convergence process resembles a pyramid. Hence, thedesignation A-plant. 13T-plants are dominated by a major divergent assembly point at final assembly, where manydifferent end items are assembled from a relatively limited number of component parts, many ofwhich are common to numerous end items. In T-plants, the critical resource and productinteractions take place at final assembly, where the product structure expands to yield a largevariety of assembled products. The narrow component base, coupled with the very expansive topportion representing the end item configurations, give rise to a product flow diagram thatresembles the letter "T." 13Both the Ford production system and the Toyota production have a commonality in theirimplicit treatment of the constraint or slowest step. Both systems seek to synchronize theremainder of the system to the slowest step, either by a physical moving line or by kanbancards. The constraint, in-turn, can be synchronized to the external market demand.
  • 23Exploitation  of  these  systems  occurs  via  “line  balancing”  and  also by inventory reduction injust-in-time.The Theory of Constraints production solution, drum-buffer-rope, in contrast is explicit in itsrecognition of the existence of constraints. As such, only the key control points of raw materialrelease, points of convergence   or   divergence,   the   constraint,   and   shipping   need   to   be   “tied”  together by the logistical system. The mechanism to tie the points together is a time-phasedschedule.Because drum-buffer-rope explicitly recognizes the constraint and exploits it’s  capability  to  the full, drum-buffer-rope is able to operate at any product volume or level of diversity.Umble and Srikanth recognize the similarities of the Ford production system, Toyotaproduction system and drum-buffer-rope under the term synchronous manufacturing. In thisclassification, the Ford production system and the Toyota production system can be viewed aspartial implementations, or sub-sets, of synchronous manufacturing and drum-buffer-rope as afull set of the capabilities. 142.4. Drum-Buffer-Rope SchedulingSenge  described  the  “where  we  are  now”  as  the  current  reality,  and  the  “where  we  want  to  be  in  the  future”  as  the  vision.  15He noted that if there was no gap between the current reality andthe vision, then there would be no need to move toward the vision. The gap between the twobecomes  a  source  of  creative  energy  which  he  termed  “creative  tension.”But  that  doesn’t  actually  help  to  move  forward. In  fact  Senge  notes  that  “creative  tension  often leads to feelings or emotions associated with anxiety, such as sadness, discouragement,
  • 24hopelessness,  or  worry.” Senge  described  this  as  “emotional  tension.” The key point is not toconfuse creative tension with emotional tension, otherwise we predispose ourselves to loweringour vision. 15We need a process of change to ensure that we move from where we are now towhere we want to be in the near future.Goldratt briefly outlined a process of change in 1990. 16He characterized it as follows;1. What to change.2. What to change to.3. How to cause the change.Goldratt furnished a focusing process in the earliest versions of The Goal, however, it wasimplicit. In later editions it was made explicit as the five focusing steps. The five focusingsteps, exactly as in the original verbalization, are as follows 17:1. Identify the  system’s  constraints.2. Decide how to exploit the  system’s  constraints.3. Subordinate everything else to the above decision.4. Elevate the  system’s  constraints.5. If in the previous steps a constraint has been broken, Go back to step 1, but do not allowinertia to cause a system constraint.Proper subordination is the key to effective implementation of Theory of Constraints. Propersubordination means that the non-constraints only do what is required to ensure maximumexploitation of the constraint. It needs to be ensured that the parts are subordinated to the whole,or more correctly in larger-scale enterprises, that the subsystems are subordinated to the system.
  • 25Once an exploitation plan has been decided upon, there are two ways to deviate from thisplan. 13Deviating from the plan means improper subordination and consequently less than fullyeffective exploitation. Deviation from the plan results from:1. Not doing what was supposed to be done.2. Doing what was not supposed to be done.Drum-buffer-rope is the Theory of Constraints production application. It is named after the 3essential elements of the solution; the drum or constraint or weakest link, the buffer or materialrelease duration, and the rope or release timing. The aim of the solution is to protect the weakestlink in the system, and therefore the system as a whole, against process dependency and variationand  thus  maximize  the  systems’  overall  effectiveness. The outcome is a robust and dependableprocess that allows more production with fewer inventories, less rework/defects, and better on-time delivery.Drum-buffer-rope however is really just one part of a two part act. If drum-buffer-rope is themotor for production, then buffer management is the monitor. Buffer management guides theway in which the motor is tuned for peak performance.In determining the buffer, the rule of thumb to apply is to halve the existing lead time. 18Tothis buffer, a second rule of thumb is applied. The buffer is divided into zones of one third each.19Most work is expected to be completed in the first 2 thirds and be waiting in front of theconstraint for the last third of the buffer time.For  all  practical  purposes  the  “time  buffer”  is  the  time  interval  by  which  the  release  of  workis   predated,   relative   to   the   date   at   which   the   corresponding   constraint’s   consumption   is  
  • 26scheduled. 7.8The zones equate to time allocated in the plant to protecting an operation whoseposition and function is critical to the timeliness and output of the whole process. The zones donot equate to the position of work in the plant.“The  reason  buffers  are  defined  as  the  whole  lead  time  and  not  just  the  safety  portion  is  that  in most manufacturing environments there is a huge difference between the sum of the netprocessing times and the total lead time. When we review the net processing time of mostproducts, we find it takes between several minutes and an hour per unit. But the lead time maybe several weeks, and even in the best environments several days. Consequently, each unit ofproduct waits for attention somewhere on the shop floor for a much longer time than it actuallytakes  to  work  on  it.” “So  it  makes  sense  not  to  isolate  the  net  processing  time,  but  to  treat  the  whole lead time as a buffer – the time the shop floor needs to handle all the orders it mustprocess.”  21.AThe above paragraphs describe the operations system in Drum-Buffer-Rope. To ensure itsstability, a monitoring system is also required. This is done through buffer management. Buffersand their purpose have already been discussed, however a mechanism is required to interpret andutilize the information that they can provide. And in order to do that, their impact must bedivided into two distinct functions. They are as follows;1. Local Control - the day-to-day exception reporting that indicates when there may be apotential due date violation.2. Global Feedback - longer term trend-reporting that suggests a particular buffer needs tobe resized to be fully effective.
  • 27Buffer management is crucial; it filters important signals from the day-to-day noise of thesystem thereby alerting the potential problems before they become real problems and it providesa self-diagnosis that neither too much and nor too little protection is made available for eachcase. The self-diagnosis feeds back into our configuration and guides improvements in theoverall dynamics of the implementation.Thus, control is also implemented along with planning, but it is local and within the contextof the overall design of the implementation. Schragenheim & Dettmer have an importantdefinition of control 21.B:“A reactive mechanism that handles uncertainty by monitoring information that indicates athreatening situation and taking appropriate corrective action before the  threat  is  realized.”Consider the rock and water analogy. The water level corresponds to the inventory level,while the rocks are the problems disturbing the flow. There are many rocks at the bottom of theriver and it takes time and effort to remove them. The question is which rocks are important toremove. The answer is given by reducing the water level; those rocks which emerge above thewater are the ones that should be removed. The drum-buffer-rope operating model controls theinventory level through time buffers while Buffer management provides a constructive controlmechanism which makes it possible to focus on areas which cause problems in the productivityof the system. This Theory of Constraints application can provide operating stability with highdue-date performance in made-to-order apparel manufacturing firms. This stability is the mostbasic requirement to drive any further improvements which add to the bottom line and aresustainable.
  • 282.2 List of References1. Goldratt (2009), 334, 335, 341, 3392. Ford (1926), 893. Ohno (1988), 18-204. Mabin & Balderstone (2000), 10-125. Lee, Hwang, Wang & Lee (2009), 426. Woeppel (2000), 17. Goldratt (1990), 26, 10, 14, 19, 238. Johnson & Kaplan (1987), 217, 49-579. Youngman (2005)10. Wheatley & Kellner-Rogers (1999)11. Scheinkopf (1999), 23-2412. Cox & Spencer (1998), 101-12813. Umble & Umble (1999)14. Umble & Srikanth (1995), 211-25515. Senge (1990), 150-15116. Goldratt, E.M (1990), 3-2117. Goldratt & Cox (1986), 30718. Goldratt (1997), 14919. Stein (1996), 14320. Schragenheim & Dettmer (2000), 123-135, 176* Citations for the above mentioned authorities are provided in chapter 09: Bibliography
  • 2903. Methodology
  • 30This paper explores the applicability of a Theory of Constraints Drum-Buffer-Rope operatingmechanism for production in a low-volume/high-mix made-to-order apparel manufacturingenvironment to establish a proactive planning & constructive control system that ensures highdue-date performance along with higher throughput, lower inventory and lower operatingexpense.3.1. Scope of ResearchThe research is limited to scheduling only production processes after the purchase of rawmaterial; grey fabric in this particular case. Purchase of trims & accessories is not explicitlyhandled and is limited to monitoring with respect to deadlines for getting materials in-house.3.2. AssumptionsPurchase of raw materials is still largely based on the archaic1notion of buying stocks whenprices are low and buying restrictively when prices are high. Due to this sporadic nature of rawmaterial purchases, it has not been included in the planning & control system described in thispaper. It has been assumed that raw material i.e. Grey Fabric is readily available whenever it isrequired for further processing. Trims & accessories are also assumed to be available forproduction as and when required.3.3. ConstraintsTheory of Constraints advocates that each system is a chain of dependent processes. Thestrength of this chain is governed by the weakest link, the bottleneck or constraint. As discussed1 “We have carefully figured, over the years, that buying ahead of requirements does not pay--that the gains on one purchase will be offsetby the losses on another, and in the end we have gone to a great deal of trouble without any corresponding benefit. Therefore in our buying wesimply get the best price we can for the quantity that we require. We do not buy less if the price be high and we do not buy more if the price below.”  – Henry Ford in “My  Life  &  Work”,  1922
  • 31earlier in section 2.4, identifying this constraint is the first step to any Theory of Constraintsapplication.3.3.1. Identifying the ConstraintA cursory glance at the various departments to identify any potential bottlenecks revealedthat few processes had much more capacity than certain others. Four departments/processes inparticular emerged as potential constraints and were studied to find if any one of them could beconclusively considered as the constraint.The daily outputs of these four processes were recorded for a period of 26 days. During thisperiod, 85% of the output constituted of three different styles with shipment dates varying withina week from one another. All three styles were floated on the floor considerably simultaneously.However, to ease out any slight fluctuations in the output of the processes due to variation instyles a 3 day moving average was used for comparing them. This comparison is illustrated inappendix A.The above comparison revealed that a single constraint does not exist. Instead, all of the fourprocesses exhibited close to equal probability of becoming the bottleneck which over a period oftime led to travelling constraints i.e. the constraint laid at a different process every day. Since anapplication of Drum-Buffer-Rope scheduling necessitates the existence of a definite constraint,this dilemma prompted the need to design a constraint.3.3.2. V/A/T and 5 Why AnalysisV/A/T analysis has been discussed earlier in section 2.3. In the pursuit of designing theconstraint, a V/A/T analysis was conducted to figure out the logical structure of the plant. The
  • 32divergence and convergent points of materials were plotted and the entire structure is presentedin appendix B. This analysis revealed that there were complex dependencies in the fourprocesses causing travelling constraints as discussed in section 3.3.A 5-Why analysis was conducted on these four processes to highlight the existence ofwastes2and to determine the root causes of problems through cause and effect logic. Thetabulation of the analysis along with a Pareto analysis of the root causes are presented inappendices C.1 to C.5.The above analysis suggested that the departmental barriers within the four processes shouldbe broken and instead of a serial structure, the four processes should be combined into acontinuous process. Creating such a continuous process of consolidated functions could alsodisentangle the logical structure of the plant by creating parallel assembly processes thus creatinga definitive T plant as shown in appendix D. Essentially, the 4 serial processes causing travellingconstraints were broken down into smaller consolidated parallel processes creating manageableindependent constraints which would act as drums3to base the drum-buffer-rope schedulingsystem on.3.3.3. Design of ConstraintOnce established that the constraint must be designed by creating consolidated processes, thefeasibility of such an environment was studied. The four processes considered for consolidationwere sewing, thread cutting, finishing and packing.2 Production Wastes as described in section 2.13 A Drum is a constraint in the system which determined the pace of the overall system.
  • 33Thread cutting was considered to be a wholly non-value adding process. Operators in sewingstage should cut the threads after finishing each operation from the root so as to eliminate theneed for a separate thread cutting process. To test its feasibility, a time study was conducted ondifferent operations of a style to identify the average increase in operation time due to this addedresponsibility (appendix E). The two approaches – incorporated thread cutting & separate threadcutting were compared on 3 measurements to conclusively determine if eliminating threadcutting as a separate process was truly beneficial (appendix F).With the thread cutting process eliminated, sewing, finishing & packing remained to beconsolidated. Lean production has the potential to create a high velocity cell but the environmentof the plant which involves high labor turnover, seasonal demand and very diverse product mixlimited4its application. However, a virtual consolidation was still possible. This did not requireany major spatial rearrangement, only a reconfiguration of how material was moved betweenthese processes. This was achieved by creating two assembly lines in the finishing floor whichcould handle finishing & packing on a continuous basis. Each such line was dedicated to workwhich it received from a particular sewing line on an hourly basis.Two such virtually consolidated drums were created and six orders were executed on themfrom the point of grey material release to shipment. These pilot runs were considered as the basisfor creating a case for the superiority of drum-buffer-rope scheduling.3.4. Applying Drum-Buffer-RopeDrum-Buffer-Rope has been discussed in section 2.4. It is the operating principle, the motorwhich drives production. It was applied through the steps described in the following sections.4 Limitation of TPS as discussed in section 2.1
  • 343.4.1. Establishing Time BuffersThe buffer is the time from the release of material to the time it is due at the drum. As a ruleof thumb, this time is established by halving the present lead time between these two points. Thelead times were determined for various product routings in order to arrive at the time buffer fordrum-buffer-rope scheduling. These times were determined by tracking certain orders as theyprogressed through production (appendix G.1 to G.9) and finding the median lead time foroutsourced processes through analysis of historical data.This time buffer protects against variation in the processes before the drum. To protectagainst any variations inside the drum, another buffer called the shipping buffer was used. Thistime buffer was the time from the end of the drum to shipping.3.4.2. Creating a Drum ScheduleFor each of the two drums, specific schedules for executing the six orders were created. Inorder to create the schedule, the work content of the product was required. In order to determinethe robustness of new system, two approaches were applied to derive the work content:1. Time study was employed to arrive at a scientific estimate of the work content.2. Intuition of line masters was used to arrive at average hourly output estimates.This drum schedule determined the material release for these orders by deducting the timebuffers from the due date at the drum. This link between material release and drum schedule isknown as the rope which prevents excess inventory in the factory.
  • 353.4.3. Buffer ManagementBuffer management is the monitoring arm of drum-buffer-rope. It is the throttle which keepsthe drum-buffer-rope motor running, tweaking it whenever necessary. It is executed by dividingthe time buffer into three equal zones and monitoring released orders accordingly. It has beendescribed in section 2.4.The orders which reach the red zone are assessed. The problem for their lateness is identifiedand recorded. At the end of the pilot runs, a Pareto analysis of these occurrences was done toidentify problem areas. Such analysis provides focus to direct any improvement efforts at non-constraints.An analysis on the buffer status of all the orders was also done to check if the time buffersestablished were less, sufficient or too generous. This allows scientific base gradual reduction ofwork-in-process.3.4.4. Comparison of Existing & Proposed SystemsAn objective comparison was made between the existing and proposed systems. Thiscomparison, amongst others consists of the following Theory of Constraints measurements:1. Throughput - Throughput is the rate at which the system generates money through sales.2. Inventory - Inventory is all the money that the system invests in purchasing things whichit intends to sell.3. Operating Expense - Operating expense is all the money the system spends in order toturn inventory into throughput.
  • 36These measures were would be valid when the entire operation is run on drum-buffer-rope.Since the implementation presented in this paper was limited to pilot runs on two drums, it couldnot be compared to the ongoing system on these measures. Thus the comparison was made onlead times and on-time-in-full deliveries.The methodology is largely based on generic principles but had to be configured to a certaindegree in order to be valid in the environment of the system of implementation. Overall, themethods described above can easily be replicated at any other made-to-order apparelmanufacturing firm.
  • 3704. Constraints
  • 38Businesses are run by entrepreneurs. Entrepreneurs are driven by a sense of purpose. In therealm of small and medium scale apparel manufacturers in the country who export to almost allmajor markets in the world, this purpose is limited to making monetary gains. With cheap laboravailable, operational practices have rarely evolved to reflect the technology and knowledgeavailable in the new century. A survey of garment factories conducted in the NCR regionpresents a sorry state of factories in one of the more mature readymade garment manufacturinghubs in the country (Annexure A). It might be the certitude of cheap labor that prevents businessowners to look beyond profits and invest on people, but this condition might not exist after tenyears. The cost of labor is increasing yet systems in garment factories are not keeping pace.SMEs in the sector might well be on the verge of obsolescence by the end of the next decade.This myopia must be eliminated; to keep the business profitable and preserve the economicbenefits this industry services the country.Ford described the true industrial idea as not to make money but to express a serviceableidea, to duplicate a useful idea, by as many thousands as there are people who need it. Theindustrial idea exists to spread prosperity. As Ford puts it, prosperity is not measured by the bankbalance of the manufacturer but by the comfort of the people at large. Businesses execute thisindustrial idea and the ultimate goal of any business, as Goldratt puts it, is to make money in thepresent as well as in the future. A truly sustainable business will only exist when it continues tomake money while contributing to increasing the comfort of its people.What then is stopping apparel SMEs from becoming truly excellent? - The ubiquitousobsession with costs. This emphasis that management puts on cost leads to management thrivingto improve local efficiencies. The underlying assumption being that improvement in localefficiencies adds up to increase the global performance of the business. It is this assumption that
  • 39must be challenged. Goldratt argues that every business is a system and every system has at leastone constraint which determines the overall performance of the system. Consider the system tobe a chain. The local optima approach measures the performance of this chain by its weight.Increasing the weight of each link increases the overall weight. But this measure is wrong. Theperformance of the chain should be determined by its strength, not weight. This strength isdetermined by the strength of the weakest link. Thus in a system of dependent processes, itsperformance is determined by the weakest process, the constraint. Theory of Constraints workson this principle and advocates that systems must be managed by their constraints. The followingexample illustrates this concept:Product X is manufactured by starting with Raw Material X and then processing it sequentially through 5operations using machines A to E respectively. This is the only use that the five machines are put to. The hourlyrates for each machine are given in the table.Operation 1 2 3 4 5Machine M/C A M/C B M/C C M/C D M/C EHourly Unit Output Rate 100 80 40 60 90This  begs  a  number  of  questions  to  help  answer,  "Why  manage  by  constraints?”Question Answer What is limiting the System?What is the maximum output per hour of ProductX?40 M/C CBy how much would the output be improved if Bwas increased to 90?No Improvement M/C CBy how much would the output be improved if Cwas increased to 50?By 10 M/C CBy how much would the output be improved if Cwas increased to 70?By 20 M/C DWhat effect on the system if M/C A can onlymanage an output of 90 in one hour?None M/C CWhat effect on the system if M/C C can onlymanage an output of 30 in one hour?We lose 10Product XM/C CWhat effect on the system if M/C B is allowed todrop to an output of 30 in one hour?We lose 10Product XM/C B for that hour. Note also that theloss cannot be recovered.
  • 40This paper explores the practical applicability of the Theory of Constraints in a high-mix/low-volume made-to-order apparel manufacturing environment through its logisticalsolution known as Drum-Buffer-Rope Scheduling to deliver high due-date performance withincreased throughput and lower inventories. The first step to execute this Theory of Constraintsapplication  was  to  identify  the  system’s  constraint.4.1.  Identifying  the  System’s  ConstraintA  typical  garment  manufacturer’s  system  comprises  of  the  following  processes  – Procurement Cutting Sewing Thread Cutting Finishing Packing DispatchIn addition to the above processes, the plant at which the research was carried out housed aprocess  of  smocking.  This  plant  manufactures  women’s  dresses,  skirts,  tops  and  blouses  across  a  wide range of printed and dyed fabrics. Grey fabric is purchased in bulk and large stocks aremaintained. This serves the dual purpose of ensuring quality of the raw material as well asmaking cost gains due to bulk purchasing at lower prices. They grey fabric is issued to variousprinters in nearby districts and to dyers within the city. After the receipt of fabric, it is checked inthe printed fabric warehouse. Checked and approved fabric is issued to cutting which is carriedout  on  piece  rate  by  contractors.  A  bird’s  eye  view  of  how  the  company  works  is  shown  below.
  • 41Trims &AccessoriesPurchaseGrey FabricPurchaseSupplierRejectAcceptIssue to Printing PrinterRejectAcceptTrims &Accessories StoreCutting SmockingSewingFinishingPackingDispatchFigure  4.1  Flowchart  of  Processes  at  MA’AM  Arts,  JaipurCheckCheck
  • 42Printing, cutting and smocking are all outsourced processes and do not present a capacityconstraint on the system. Thus, the remaining four departments of sewing, thread cutting,finishing and packing were examined to find which one of them was the constraint.The daily outputs of all the four departments were recorded for a period of 26 days from 8thMarch to 7thApril, 2010. During this period of study, the following orders were produced.Style No. Description QuantityUU76786 Women’s  Top 42000AT91007-3 Women’s  Top 235008R465 8 Tier Skirt 380008P520 Women’s  Dress 40008P255 Women’s  Dress 32008P264 5 Tier Skirt 28008N288 Maxi Dress 2000Total 115500Table 4.1 Style Produced between 8thMarch, 2010 and 7thApril, 2010Source:  MA’AM  Arts,  JaipurThe above table shows that almost 85% of the total quantity produced in this periodcomprised of only 3 styles – UU76786, AT91007-3 and 8R465. To compensate for anyfluctuations in daily outputs, a 3 day moving average was considered to compare the outputs(appendix A). This revealed the frequency of each department becoming the bottleneck (Figure4.2). This led to the conclusion that each of the four departments is a potential constraint.However, a clear constraint does not emerge. This travelling of bottlenecks creates a lot ofvariation. To offset this variation, inventory is accumulated leading to longer lead times andquality problems.
  • 43Figure 4.2 Shifting BottlenecksA 5-Why analysis of the most immediate problems faced in these departments pointedtowards to following aspects - High Work in Process Inventory Absence of a Material Release Mechanism Focus on Improving Local Efficiencies Quality and Productivity Treated as separate functionsA closer look at these processes through the lens of value5reveals that these processes shouldbe carried out continuously. A value-adding ratio of these four processes was calculated to be1.29% from a value stream map (appendix H). Such a low ratio can be directly attributed to the5 “Value  can  only  be  defined  by  the  ultimate  customer.  And  its  only  meaningful  when  expressed  in  terms  of  a  specific  product,   whichmeets the customers needs at a specific price at a specific time." - Womack & Jones, Lean Thinking. For this case, value is considered as anyactivity for which the customer is willing to pay for.0123456789Sewing Thread Cutting Finishing PackingBottleneck Frequency
  • 44long queue and wait times. This can be eliminated if these four processes were consolidated intoa single process.These four departments were analyzed through another lens – That of V/A/T analysis.Goldratt introduced the concepts of V, A & T Plants. He analyzed various manufacturing plantsand concluded that there are essentially 3 plant structures resembling the letters V, A and T.These structures are created by analyzing divergence and convergence points of products &processes.The  plant  under  consideration,  MA’AM  Arts  was  analyzed on these lines. The structure ispresented in Appendix B. The plant distributes is processes in the following way – Cutting is carried out through contractors as already mentioned previously. 9 Sewing lines Thread Cutting through two contractors with   varying   capacities   as   per   the   plant’s  requirements 2 floors for Finishing and PackingAlthough the structure did not reveal a distinct shape, the plant exhibited much of thecharacteristics of a T-Plant –“T-plants are dominated by a major divergent assembly point at final assembly, where manydifferent end items are assembled from a relatively limited number of component parts, many ofwhich are common to numerous end items. In T-plants, the critical resource and product
  • 45interactions take place at final assembly, where the product structure expands to yield a largevariety  of  assembled  products.”  64.2.  Designing  the  System’s  ConstraintThe consolidation of these processes need not be physical. Physical consolidation of theseprocesses could have employed the principles of lean manufacturing. Although preferable understable conditions, physical consolidation was not practicable under the volatile conditions of theplant under consideration. At this time, the following challenges lay ahead – A constraint was required to design the Drum-Buffer-Rope application The four travelling bottlenecks could not have been physically consolidatedA logical consolidation was however very easily possible. This consolidation is explainedlater in the next section.This logical consolidation provides a solution to both the challenges stated above. Iteliminates the problem of travelling constraints by creating truly parallel processes thus revealinga clear T-Plant structure (Appendix D). Each of these branches creates a set of parallelconstraints. The throughput of these constraints determines the overall throughput of the plant.Since these constraints set the pace of the plant, they become the drum in the Drum-Buffer-Ropemechanism as explained in the next chapter.Wherever the processes required by a garment are broken down and carried out by separatedepartments, work-in-process increases and the problem of travelling bottleneck arises. Thisarises from the notion of balancing capacities. Balancing capacities can never deliver output as6 Umble & Umble, 1999
  • 46per plans due to two important factors – statistical fluctuations and dependent processes. Instead,the flow of production must be balanced7. This balancing of flow is only possible when thesubsequent processes are not displaced too much from each other. Even if they are not putphysically together, their distance may be reduced on a scale of time. The constraint, in suchfragmented conditions need not be identified but rather designed. The design should arise fromthe environmental limitations. This design can be developed by –1. Measuring the distance between subsequent processes on a scale of time2. Minimizing this distance to as low as practically possibleThe  constraint  must  be  designed  to  be  located  at  the  system’s  end.  Eventually, the constraintwill move into the market. When that happens, demand will become the constraint and the closerthe previously designed constraint is placed to this demand i.e. the shipping schedule, the moreproductive the system will become as this configuration would implicate a pull system by itsvery nature thus reducing inventory and improving throughput.4.3.  Exploiting  the  System’s  ConstraintOnce the constraint has been designed, an exploitation strategy must be devised to extract thehighest throughput from it. In the following paragraphs, the exploitation strategy applied atMA’AM  Arts,  Jaipur  is  described.  This  strategy  is  based  on  the  following generic points –1. Improve the throughput rate of the ultimate output of the consolidated processes.2. The time between point of inspection and point of operation should be reduced to aslow as possible.7 Refer the dice game as illustrated in the book “The  Goal”  by Eliyahu M. Goldratt.
  • 473. Any unnecessary steps must be eliminated.The first irritable observation was a separate thread cutting department. Operators in theirregular course of sewing have to cut thread after each operation. The operator should cut thethreads from the root themselves, thus eliminating the need for separate thread cutting at a laterstage. A time study was performed on a particular style where operators were instructed to cutthe thread themselves (Appendix E). This increased the work content of the garment by only2.05 minutes, reducing the average hourly output in sewing from 41 to 39 but reducing the leadtime from sewing to finishing from 30 hours to just 10 hours. A cost analysis of thread cutting byseparate department versus thread cutting at source clearly shows that it is more profitable whenthe threads are cut by the operators themselves (Appendix F).Since thread cutting was included as a part of sewing operations, the remaining three distinctprocesses of finishing and packing remained to be consolidated. This was achieved by linking asewing line with a finishing cell8. The finishing cell was expanded to include packing activitiessuch as tagging, folding, adding hangers and packing garments into polybags (Appendix I). Thislink was logical rather than physical. The sewing line and finishing cell were on different floors.An  inventory  of  1  hour’s  work  was  fixed  between  them.  This  translated  to  the  hourly  output  from  the sewing line being fed to the finishing & packing cell.The finishing & packing cells were much more robust than the sewing lines. Manpowercould easily be added or removed from a cell to balance the flow of units. The only job of thesupervisor was to make sure that the finishing & packing cell was sufficiently manned tocomplete  one  hour’s  worth  of  output  from  the  sewing  lines  every  hour. The hourly target of the8 Dewan & Sihmar (2010)
  • 48cell was to produce tagged and folded garments (or hanger, as the case may be) stored size-wiseon racks.The ultimate output of the designed constraint was to produce packed goods. Garments arepacked in polybags as per customer specifications. It may be any one of the followingconfigurations.Packing Polybag (Sizes)Carton (Colorways) Solid AssortedSolid 1 2Assorted 3 4Table 4.2 Types of Packing1. Solid-Solid – Each carton contains polybags in the same colorway with each polybagcontaining a specified number of pieces of the same size.2. Assorted-Solid – Each carton contains polybags in a specified ratio of colorways witheach polybag containing a specified number of pieces of the same size.3. Solid-Assorted – Each carton contains polybags in the same colorway with eachpolybag containing pieces in a specified size ratio.4. Assorted-Assorted – Each carton contains polybags in a specified ratio of colorwayswith each polybag containing pieces in a specified size ratio.Thus, the aim of the constraint is to produce items in such a way that they can be packed atthe end of the day. The most common type of packing is type 3. This can be achieved if each lineis fed in batches containing all sizes in ratio. This batch size is subjective and would wary fromproduct to product. The following rule of thumb was applied to arrive at a batch size –
  • 49𝐵𝑎𝑡𝑐ℎ  𝑆𝑖𝑧𝑒 = 𝑀𝑢𝑙𝑡𝑖𝑝𝑙𝑒  𝑜𝑓  𝑆𝑖𝑧𝑒  𝑅𝑎𝑡𝑖𝑜  𝑐𝑙𝑜𝑠𝑒𝑠𝑡  𝑡𝑜  𝐸𝑠𝑡𝑖𝑚𝑎𝑡𝑒𝑑  𝐷𝑎𝑖𝑙𝑦  𝑂𝑢𝑡𝑝𝑢𝑡2Thus, by the end of the day, all sizes would be available for packing in two cycles. Anillustration of this system in explained in greater detail in the table below. The robustness of thefinishing & packing cell was used to keep the bottleneck in the constraint within the sewing line.This prevented any overproduction downstream of sewing. The timing of the workers in thefinishing   and   sewing   cells   was   offset   by   an   hour   so   that   the   day’s   sewing   output   could   be  finished and packed.Avg. Hourly Output 50 PiecesFeedS M LFeed for Day 400 1 2 3No. of Lots 2 x 200 A 50 100 50Size Ratio S:M:L = 1:2:1 B 50 100 50TimeSewing Finishing/PackingPolybagS M L S M L09:30 - 10:30 50 - - - -10:30 - 11:30 50 5011:30 - 12:30 50 5012:30 - 01:30 50 5002:30 - 03:30 50 50 5003:30 - 04:30 50 5004:30 - 05:30 50 5005:30 - 06:30 50 506:30 – 07:30 50 50Table 4.3 – Illustration of production within the drumA supervisor was made responsible for this entire consolidated constraint. It was hisresponsibility to maintain a regular flow of goods through it. This system of working allowedthe constraint to work with lesser inventory and shorter lead times. Much of the queue andwaiting times were eliminated to result in a more robust overall system.
  • 5005. Drum-Buffer-Rope
  • 51Manufacturing is at the heart of our industrialized economies. Productivity, thus, is anindispensible measure. It is the consequence of the production system – the mechanics that turnthe wheels of any manufacturer. Drum-Buffer-Rope is the motor which can drive this productionsystem and Buffer Management is the throttle to control this motor. How these two Theory ofConstraints logistical solutions are applicable to made-to-order apparel manufacturing isdescribed in this chapter.5.1. The DrumThe drum is the constraint in a system. It sets the pace at which the entire system works. Theconstraints have been described in the previous chapter. This chapter deals with how theseconstraints can be used as drums to run the production system.Each of the designed constraints is a drum. The system cannot produce any more than whatthese drums can produce. Since the drums constitute the throughput of the system, they mustwork as best as they can. How these drums were exploited for performance has already beendescribed in the previous chapter. The focus now is on a broader view of the system.In a series of dependent processes, statistical fluctuations always occur. These fluctuationscause variability. In order for the drums to operate continuously without ever being exhausted insupply from upstream processes, they must be shunned from any variability. This protection isprovided by maintaining buffers before the drums. Traditionally, each process is protected bymaintaining buffers in front of them. However, in drum-buffer-rope, buffers are measured on a
  • 52scale of time instead of physical count. The entire time from material release to the start ofoperation at the drum is considered as the buffer.95.2. The BufferGoldratt suggests that the time buffers must be established by applying a simple rule ofthumb, without getting into data collection and complex calculations.𝑇𝑖𝑚𝑒  𝐵𝑢𝑓𝑓𝑒𝑟 =𝐿𝑒𝑎𝑑  𝑡𝑖𝑚𝑒  𝑓𝑟𝑜𝑚  𝑚𝑎𝑡𝑒𝑟𝑖𝑎𝑙  𝑟𝑒𝑙𝑒𝑎𝑠𝑒  𝑡𝑜  𝑑𝑟𝑢𝑚2To arrive at this time buffer, the lead time from release of grey material to beginning ofsewing was required to be calculated. In general two kinds of processing is required by the greyfabric – Printing and Dyeing. This time was calculated by tracking 9 running orders from greyissue to dispatch. The tracking of these orders is presented in appendix G.1 to G.9. However, allof these orders required dyed fabric. Orders requiring printed fabric were scheduled for sewing ata time beyond the duration of this phase of the research. Thus, only historical lead times forprinting could be collected. The lead time from receipt of material to start of sewing wasdetermined from the 9 orders which were actually tracked. This time was added to the lead timefor printing to arrive at the time buffer for orders requiring printed fabric. The orders weretracked  by  “Sheet  Numbers”  – the  plant’s  term  for  uniquely  identifying  each  product.The lead times and time buffers derived from them are described in Table 5.1 A and 5.1 Bbelow. These time buffers in front of the drum are called production buffers. Their purpose is toprotect the drum against variation in upstream processes. The production was tracked by9 This concept has been explained by Schragenheim and Dettmer. See 21.A in the Review of Literature.
  • 53recording the daily output for each Sheet Number. Since sewing lines required up to six hours togenerate an output, the start of sewing is considered to be one day before the output is recorded.Sheet No.Grey IssueStartReceiveStartReceiveEndSewingStartLead Time Lead TimeA B C D E F = C to E G = B to E1664 A 22/2 8/3 18/3 17/3 10 241664 B 18/2 26/2 28/2 10/3 13 211664 C 18/2 26/2 28/2 15/3 18 261664 D 16/2 13/3 16/3 18/3 6 311664 E 10/2 20/2 22/3 7/3 16 261664 F 16/2 20/2 3/3 14/3 21 271660 A 20/3 22/3 22/3 5/4 15 171660 B 6/3 13/3 13/3 2/4 21 281660 C 10/3 27/3 27/3 6/4 11 28Median Lead Time 15.5 ~ 15 26Table 5.1 A - Lead time from Material Release to Sewing for Dyed ProductsSheet No.Grey IssueStartReceive Start Receive End Lead Time Lead TimeH I J K L = I to J M = Medianof F + L1545 A 21/1 14/2 3/3 25 401598 A 2/1 22/1 27/1 21 361598 B 26/12 17/1 17/1 23 381598 C 4/1 30/1 30/1 27 421598 D 6/1 19/1 23/1 14 291531 A 17/1 9/2 12/2 24 391531 B 23/1 3/2 6/2 12 271531 C 22/1 3/2 19/2 13 28Median Lead Time 37Table 5.1 B – Lead time from Material Release to Sewing for Printed ProductsThe production buffer was calculated by applying the rule of thumb to the above lead times.The median lead times were considered for this purpose as they represent the most likely
  • 54situation. The buffers for dyed and printed products were calculated as 13 and 18.5 daysrespectively. However, these times need not be strictly followed. If one strongly feels to increaseor decrease this time within reasonable limits, it should be done.Since solid dyeing is outsourced to dyers within the city of the plant, 13 days seemed toolong. It was reduced to 10 days. Printing is carried out by suppliers in another district. Sincethere is lower control over them, the buffer was increased from 18.5 to 20 days.Thus, the production buffer size for dyed and printed products were determined to beProduct Type Production Buffer SizeDyed 10 DaysPrinted 10 DaysTable 5.2 – Production Buffer SizeThis production buffer protects the drum against variation in upstream processes. But anotherkind of variation must also be considered, the variation within the drum itself. This variation isprotected by a shipping buffer, the time from the end of the drum to shipping. A similar processto that followed for determining the production buffer can be used to calculate the shippingbuffer. In this case, the drum was at the end of the system. A one day shipping buffer shouldhave been sufficient but to add more safety, a two day shipping buffer was used. The drum andbuffers are shown in the figure below.DyedPrintedProduction Buffer Drum Shipping BufferFigure 5.1 – Drum and Buffer
  • 555.3. The RopeThe output of the system is determined by the output of the constraint. Hence, releasing morematerial than the constraint can use will only increase inventory without affecting the system.The release of material should be choked. It must be linked to the schedule of the drum. Thefigure below shows the effect of choking material release on due date performance.Figure 5.2 - Real life example of the effect of choking the release on the due date performanceSource: Goldratt, 2009It clearly shows that choking material release by linking it to the drum schedule hasimmediate  positive  impact  on  a  plant’s  due  date  performance.  
  • 565.4. Drum-Buffer-Rope ScheduleThe above concepts were applied to execute three production orders comprising nine sheetnumbers. The plant approved the use of two sewing lines, thus two drums, to run these orders.The details of these orders in presented in tables 5.3 A and 5.3 B below.Style # Sheet # Description QuantitySize RatioS M L XLU-98811738 F Dyed 5 Tier Skirt 3200 800 1600 8001738 G Dyed 5 Tier Skirt 3200 800 1600 8001738 H Dyed 5 Tier Skirt 4800 1200 2400 1200DM-10-32 1732 A M&M Printed 5 Tier Skirt 600 100 200 200 100DM-10-41 1732 B M&M Printed 5 Tier Skirt 600 100 200 200 100DM-10-31 1732 C M&M Printed 5 Tier Skirt 600 100 200 200 100DM-10-37 1732 D M&M Printed 5 Tier Skirt 600 100 200 200 100UU767711714 A Women’s  Top  /w  Lace 504 84 168 168 841714 B Women’s  Top  /w  Lace 432 72 144 144 72Table 5.3 A – Details of orders executed on the DrumSheet # Due Date1738 F17 April, 20101738 G1738 H1732 A22 April, 20101732 B1732 C1732 D1714 A25 April, 20101714 BTable 5.3 B – Due dates of orders executed on the Drum
  • 57These due dates represent the shipping schedule. Subtracting the shipping buffer from thisshipping schedule would determine the end date of the order at the drum. To determine the startdate at the drum to create the drum schedule, the estimate of the lead time at the drum isrequired. This may be achieved by in two ways –1. Conducting time study to determine the work content of the garment2. Using estimates provided by sewing & finishing line supervisorsTime estimate determined by time study was used for four sheets. For the remaining fivesheets, the estimates provided by the supervisors were used. An estimate of the learning curvewas also required. This learning curve was considered in the form of percentage of the estimatedhourly output as expected on a particular day from the start of production on a style. The hourlyoutput from sewing and learning curve estimates for each style is shown below. Each sewing lineconsisted of 36 machines.Sheet # SAMLearning Curve (%)Average Hourly OutputI II IIIU-9881 - 45% 80% 100% 48DM-10-XX 32.5 45% 80% 100% 45UU76771 - 45% 80% 100% 50Table 5.4 – Estimating Work ContentNow, three essential data were available to create the schedule.1. Shipping Schedule2. Time Buffers3. Work Content at Drum
  • 58With this information, the date of start at drum and material release can be determined. Theprocess is illustrated in the table below.Ex-Factory Date A DateShipping Buffer B DaysWork Content at Drum C DaysStart Date at Drum D DateProduction Buffer E DaysMaterial Release F DateD = A – B – C and F = D – EFor Example, ifA = 17thApril, B = 2 Days, C = 10 Days and D = 10 DaysThus,D = 17thApril – 12 Days = 3rdApril andF = 3rdApril – 10 Days = 22ndMarch(While calculating, only working days are considered)Figure 5.3 – Determining Drum Start and Material ReleaseThe above stated method was used to determine the drum schedule of two drums. Estimatesof the work content were used to determine the due dates at the drum. For sake of control andchecking the validity of the drum, each was explicitly planned. One plan is shown in the tablebelow. Plans for each sheet are shown in appendices J.1 & J.2.
  • 59Average Hourly Output 44CumulativeFeed Batch Size 180Day Output S M L XL S M L XL1 280 60 120 70 30 60 120 70 302 350 55 86 136 73 115 206 206 1033 350 48 120 120 60 163 326 326 1634 350 43 86 86 43 206 412 412 206Day Status at End of DayPackedRatio - 1:2:2:1S M L XL S M L XL Total1 60 120 70 30 30 60 60 30 1802 85 146 146 73 73 146 146 73 4383 60 120 120 60 60 120 120 60 3604 43 86 86 43 43 86 86 43 258Table 5.5 – Detail plan for Sheet No. 1732 A and 1732 B fed to Drum I consecutivelySuch detailed planning at the drum allows for better estimates of the work duration at thedrum. Once these durations are calculated, the drum schedule must be prepared. The drumschedules for both drums used for the application are given below. These drum schedules mustbe  strictly  followed  as  any  deviation  in  these  drums  directly  impacts  the  system’s  throughput.The drum schedule is a simple list of work orders. The supervisor of a drum is maderesponsible for making sure that each work order is started precisely as per the schedule. Thedrum supervisor must ascertain the availability of cut parts, trims and accessories from upstreamprocesses. In case of any problem, the buffer manager is intimidated for resolution of the matter.
  • 60Sheet #Date Drum I Drum II27/3 1738 H N/A28/3 Sunday29/3 1738 H 1738 F30/3 1738 H 1738 F31/3 1738 H 1738 F1/4 1738 H 1738 F2/4 1738 H 1738 F3/4 1738 H 1738 F4/4 Sunday5/4 1738 H 1738 F6/4 1738 H 1738 F7/4 1738 H 1738 F8/4 1738 H 1738 F; 1738 G9/4 1738 H 1738 G10/4 1738 H 1738 G11/4 Sunday12/4 1738 H;1738 G 1738 G13/4 1738 G 1738 G14/4 1738 G; 1732 A 1738 G; 1732 C15/4 1732 A 1732 C16/4 1732 A; 1732 B 1732 C; 1732 D17/4 1732 B 1732 D18/4 Sunday19/4 1732-B & 1714 A 1732 D20/4 1714 A N/A21/4 1714 A; 1714 B N/A22/4 1714 B N/ATable 5.6 – Drum ScheduleThe material release schedule was created with respect to this drum schedule. Thissynchronization between material release and the drum schedule is the most essential step of aTheory of Constraints application. It subordinates all activities to the constraint. The materialrelease schedule is also called the gating schedule. It is shown in the table below.
  • 61Date Sheet #Upper Lining(Meters) (Meters)16/3 1738 H 8100 318017/3 1738 F 5380 215022/3 1732 A 112522/3 1732 C 112524/3 1732 B 112524/3 1732 D 112527/3 1738 G 5380 21502/4 1732 A 4002/4 1732 C 4005/4 1732 B 4005/4 1732 D 4007/4 1714 A 490 1258/4 1714 B 410 110Table 5.7 – Material Release Schedule5.5. Buffer ManagementSo far the concept of DBR has been discussed; however there is a second part of this actwhich is equally important and imperative for successful implementation of DBR. This secondpart is Buffer management; it is the control system that allows us to keep a running check on thesystem’s   effectiveness. The drum-buffer-rope model, once established, needs a monitoringsystem to keep it in control which is achieved by buffer management. Buffer managementsurfaces the important signals from the system warning us against the potential problems andalso acts as a litmus test to check whether too much and or too little protection is being given forany order. Before understanding the role of buffer management, the role of buffers must meclearly understood.
  • 62In a make-to-order environment, timeliness is of utmost importance. Buffers protect thetimeliness of the system by subordinating the raw material release and all other steps up to thedrum origin so that materials arrive in good time to be processed as planned and finished goodscan be shipped at the planned time. This is the role of buffers.Buffer management begins by dividing the time buffers in to three equal/unequal zones.Suppose the production buffer is of nine day; the first zone (green zone) would span for the firstthree days, the second zone (yellow zone) would span the next three day and the third buffer (redzone) would span the last three days. We expect most work to be completed in the first twothirds and be waiting in front of the constraint for the last third of the buffer time. Thus in theabove mentioned example, one expects the work to take about 6 days of processing and waiting-in-process, and then sitting in front of the drum for 3 days. If the materials are not ready for thedrum by the start of the third zone, the work order must be expedited to make sure that drumschedule is not disturbed. The figure shown below illustrates zoning of the production buffer.9 Day Production BufferI II III1 2 3 4 5 6 7 8 9Green Zone Yellow Zone Red ZoneFigure 5.4 – Zoning of BuffersIn the case of implementation, the following zones were used1. Production Buffer for Printed – 20 Daysa. Zone I - Day 1 to Day 8 - 8b. Zone II - Day 9 to Day 14 - 6c. Zone III - Day 15 to Day 20 - 6
  • 632. Production Buffer for Dyed – 10 Daysa. Zone I - Day 1 to Day 4 - 4b. Zone II - Day 5 to Day 7 - 3c. Zone III - Day 8 to Day 10 - 3Buffer management can be used for local control in order to avoid deviation from the drumschedule or global feedbacks to address any buffer related issues for effective implementation ofdrum-buffer-rope.5.5.1 Local Control – Buffer statusBuffer status tells the status of an order that has already been released into the system.Schragenheim defines buffer status as𝐵𝑢𝑓𝑓𝑒𝑟  𝑆𝑡𝑎𝑡𝑢𝑠  (%) =𝐵𝑢𝑓𝑓𝑒𝑟  𝐷𝑢𝑟𝑎𝑡𝑖𝑜𝑛 − 𝑅𝑒𝑚𝑎𝑖𝑛𝑖𝑛𝑔  𝐷𝑢𝑟𝑎𝑡𝑖𝑜𝑛𝐵𝑢𝑓𝑓𝑒𝑟  𝐷𝑢𝑟𝑎𝑡𝑖𝑜𝑛  𝑥  100In other words buffer status indicates how much part of the total buffer has been exhausted.For example, the production buffer for printed products was taken as 20 days. On the 7thday thebuffer status would be or 35%. A buffer status chart which has all the orders released intothe system helps to know the orders which might deviate from the planned schedule. If the bufferstatus of any order is above 70% it indicates that the order has entered the red zone of the bufferand needs to be expedited in order to prevent due date violation. Thus a daily buffer status chartfor all the released orders would indicate which orders require management attention to avoidany divergence from the schedule.
  • 64A similar chart was maintained for all the released orders. In certain cases, it helped ininsinuating the necessary actions to avoid deviation from schedule. The buffer status report ispresented in Appendix K.5.5.2. Global Feedback - Buffer HoleA buffer hole is the depth or the duration by which the red zone has been penetrated. It is ameasure  of  the  system’s  stability  and  suggests  whether  the  current  buffer  duration  is  apt  or  not.  If  most of the orders lie in the green zone it implies that the buffer is more and unnecessary excessinventory is being put into the system. Similarly if most of the orders are in the red zone itimplies that the buffer is small and should be increased to avoid any deviation from the schedule.Buffer holes for the orders run using the drum-buffer-rope model are shown in the figuresbelow.Figure 5.5A – Buffer holes in production buffer for dyed products00.511.522.5Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Day 8 Day 9 Day 10
  • 65Figure 5.5B Buffer holes in production buffer for printed productsIn case of dyed products the incidences of buffer holes were less. However, in case of printedproducts, the incidences of buffer holes were very high and thus called for improvements.5.5.3. Global Feedback –Reason code analysisThe data obtained from buffer management can be used to direct improvements. An analysisof all the orders gives a trend of receiving various orders in various buffer zones. The cause foroccurrence of red zone and frequency for each cause can be recorded. Necessary actions can thenbe taken so that these causes are not repeated in the future or at least their frequency is reduced.The following figure shows the different zones in which the production buffers for the workorders were exhausted. It is followed by a table listing the causes for penetration of the red zonewith their frequency.00.511.522.5Day1Day2Day3Day4Day5Day6Day7Day8Day9Day10Day11Day12Day13Day14Day15Day16Day17Day18Day19Day20
  • 66Figure 5.6 – Buffer ExhaustionReason Code Analysis (Red Zone )Reason FrequencyLate arrival of Print/Dye fabric 6Cutting 1Total 7Recommended ActionIncrease the buffer duration for printed materials.Table 5.8 – Reason Code Analysis5.5.4 Local MeasurementsApart from local controls and global feedbacks, buffer management is also helpful inmeasuring two important aspects of a system - Throughput & Inventory. Whenever an order islate and needs to be measured there is always confusion whether it should be measured in termsof late days or sales value. Measuring in terms of just one criterion might result in underestimation of the magnitude of a large order late by just 1 day or a small order late by severalGreen Yellow Red012345678
  • 67days but of a low sales value. Buffer management addresses this old problem by taking a productof the two factors. It is called throughput dollar days.Goldratt suggests that in order to avoid late deliveries, the lateness should be tied to bufferholes. Whenever a task does not arrive at its buffer-origin even though enough time has elapsedsince its release, it is likely to cause due date variation. Thus, we might start to count the daysfrom the point in time when the task penetrated into the red zone, rather than from the orderdue-date. This delay is called Lateness.𝐿𝑎𝑡𝑒𝑛𝑒𝑠𝑠 = 𝐴𝑐𝑡𝑢𝑎𝑙  𝐷𝑢𝑟𝑎𝑡𝑖𝑜𝑛 − 𝐵𝑢𝑓𝑓𝑒𝑟  𝐿𝑒𝑛𝑔𝑡ℎ − 𝐿𝑎𝑠𝑡  𝑍𝑜𝑛𝑒  𝐿𝑒𝑛𝑔𝑡ℎUsing buffer management this way provides the probable location of the problem and itsfrequency;;  however  from  the  system’s point of view it is more plausible to have some measureof severity. More the throughput is at stake, and more the days are late; more severe is theproblem. Stein advocates that using this measure of severity in buffer hole Pareto analysis givesa more clear and reliable picture of the system.𝑆𝑒𝑣𝑒𝑟𝑖𝑡𝑦 = 𝑇ℎ𝑟𝑜𝑢𝑔ℎ𝑝𝑢𝑡  𝑥  𝐿𝑎𝑡𝑒𝑛𝑒𝑠𝑠Sheet No. Throughput Lateness Severity1732 A 88800 3 2664001732 B 88800 4 3552001738 C 88800 2 1776001738 D 88800 2 1776001738 F 280160 2 5603201738 H 420240 3 12607201738 B 34344 1 34344Table 5.9 – Severity
  • 68A daily location wise severity chart assigns the resulting measure to the unit where theprocess is stuck and might cause a due date variation. Sometimes it might give a false picture asthat department might not be responsible for the lateness - but the result to the system is theultimate goal. The centre that inherits the problem will, in effect, expedite the resource with aseverity tied to it and try to move it out of the department as soon as possible. The quality controldepartment however should make it sure that the work done is not sloppy in this case.Such daily location wise measure of severity was done for the implemented orders to makesure that an order with severity tied to it has a higher priority at the non-constraint resources. Thetable below gives the magnitude of severity on a particular day and the department to which itbelongs.Department 24-Mar 25-Mar 07-Apr 08-Apr 09-Apr 10-Apr 12-AprPrinting/DyingReceive420240 88800 177600 88800Print Checking 177600 266400Cutting 1120640 88800 88800SmokingTable 5.10 – Daily Severity Chart
  • 6906. Results
  • 706.1. Planned v/s ActualThe planned orders were fed into the system and the actual performance was measured togauge the effectiveness of scheduling. When the orders were planned daily estimates of thedrum’s  output,  total  number  of  pieces  packed,  status  at  the  end  of  day  and  number of unpackedpieces were estimated. These factors were then compared with actual data collected from theimplementation. One such comparison is shown in the table below.Date 15/4Status at Drum Output S M L XL TotalSewingExpected 60 120 70 30 280Actual 60 120 80 30 290Available for Pack at End of DayExpected 60 120 70 30 280Actual 60 120 80 30 290PackingExpected 30 60 60 30 180Actual 30 60 60 30 180Un-Packed (Waiting for Size Ratio)Expected 30 60 10 0 100Actual 30 60 20 0 110Table 6.1 – Planned v/s Actual at Drum 1 on 15thAprilIn most cases, the actual output did not exactly match the planned output but most of themwere completed in the planned drum duration. The daily packed output as planned and as itoccurred in reality were compared for both the drums. It revealed that although there weredeviations  within  an  order’s  schedule,  it  largely  evened  out  to  be  completed  on  time.  It  shows  that keeping the bottleneck in the drum within sewing allows greater control and better accuracyof planning.
  • 71DRUM 1Date Sheet No. Planned ActualCumulativePlanned Actual Deviation27/3 1738 H 40 0 40 0 100.029/3 1738 H 360 400 400 400 0.030/3 1738 H 400 400 800 800 0.031/3 1738 H 400 360 1200 1160 3.301/4 1738 H 400 360 1600 1520 5.002/4 1738 H 320 280 1920 1800 6.303/4 1738 H 320 400 2240 2200 1.805/4 1738 H 360 400 2600 2600 0.006/4 1738 H 400 400 3000 3000 0.007/4 1738 H 400 400 3400 3400 0.008/4 1738 H 400 400 3800 3800 0.009/4 1738 H 400 400 4200 4200 0.010/4 1738 H 400 400 4600 4600 0.012/4 1738 H; 1738 G 400 400 5000 5000 0.013/4 1738 G 400 400 5400 5400 0.014/4 1738 G; 1732 A 520 520 5920 5920 0.015/4 1732 A 180 180 6100 6100 0.016/4 1732 A; 1732 B 438 438 6538 6538 0.017/4 1732 B 360 360 6898 6898 0.019/4 1732 B; 1714 A 258 258 7156 7156 0.020/4 1714 A 180 0 7336 7156 2.521/4 1714 A 342 120 7678 7276 5.222/4 1714 A; 1714 B 444 330 8122 7606 6.423/4 1714 B 0 516 8122 8122 0.0Table 6.2 – Planned vs Actual comparison for packed output at Drum 1
  • 72DRUM 2Date Sheet No. Planned ActualCumulativePlanned Actual Deviation29/3 1738 F 40 0 40 0 100.030/3 1738 F 360 400 400 400 0.031/3 1738 F 400 400 800 800 0.001/4 1738 F 400 400 1200 1200 0.002/4 1738 F 400 360 1600 1560 2.503/4 1738 F 320 440 1920 2000 4.205/4 1738 F 320 400 2240 2400 7.106/4 1738 F 360 400 2600 2800 7.707/4 1738 F 400 400 3000 3200 6.708/4 1738 F; 1738 G 400 400 3400 3600 5.909/4 1738 G 400 400 3800 4000 5.310/4 1738 G 400 400 4200 4400 4.812/4 1738 G 400 400 4600 4800 4.313/4 1738 G 400 560 5000 5360 7.214/4 1738 G; 1732 C 520 160 5520 5520 0.015/4 1732 C 180 360 5700 5880 3.216/4 1732 C; 1732 D 438 438 6138 6318 2.917/4 1732 D 360 438 6498 6756 4.019/4 1732 D 258 0 6756 6756 0.0Table 6.3 – Planned vs Actual comparison for packed output at Drum 26.2. The Drum-Buffer-Rope ScheduleThe orders which were run on the developed scheduling model were tracked to record theirperformance against the planning. Their progress is presented in a calendar form below. Thechart shows the progress of each sheet number through the various processes along which it wasrouted.
  • 73DateMarch, 2010 April, 201016 17 18 19 20 22 23 24 25 26 27 29 30 31 01 02 03 05 06 07 08 09 10 12 13 14 15 16 17 19 20 21 22 23 24 251738 F1738 G1738 H1732 A1732 B1732 C1732 D1714 A1714 BTable 6.4 – Progress of Order scheduled by Drum-Buffer-Rope (Sundays are excluded)
  • 746.3. New v/s OldThe orders executed using the drum-buffer-rope model is compared to orders that were run asthe  on  the  plant’s  conventional  method.  The  comparison  is  shown  in  the  table  below.Sheet No.Printed/DyedQty. Due dateActualdateDue datevariationOn TimeIn FullLead time -Grey issueto SewingStartConventional Planning1664 A Dyed 3904 17/3 24/3 8 No 241664 B Dyed 3680 17/3 24/3 8 No 201664 C Dyed 4144 17/3 24/3 8 No 261664 D Dyed 3456 17/3 24/3 8 No 301664 E Dyed 4144 17/3 24/3 8 No 261664 F Dyed 3680 17/3 24/3 8 No 271660 A Dyed 1200 27/3 12/3 17 No 171660 B Dyed 1150 27/3 12/3 17 No 281660 C Dyed 1150 27/3 12/3 17 No 28Drum-Buffer-Rope1732 A Printed 600 22/4 22/4 0 Yes 201732 B Printed 600 22/4 22/4 0 Yes 201732 C Printed 600 22/4 22/4 0 Yes 201732 D Printed 600 22/4 22/4 0 Yes 201738 F Dyed 3200 17/4 17/4 0 Yes 101738 G Dyed 300 17/4 17/4 0 Yes 101738 H Dyed 4800 17/4 17/4 0 Yes 101714 A Dyed 504 25/4 25/4 0 Yes 101714 B Dyed 432 25/4 25/4 0 Yes 10Table 6.5 – Performance Comparison
  • 7507. Limitations and Scope of Further Study
  • 76In this paper, the applicability of Theory of Constraints Drum-Buffer-Rope as a planning andcontrolling system was illustrated. Although the concepts are generic in nature, their applicationwill be different in different environments. The case of implementation presented herein is onlyone instance of this application. The implications however, can be generalized. Reducinginventory will always lead to shortened lead times. Drum-Buffer-Rope provides a mechanism tomeasure inventory on a scale of time and keep it to as low as the plant can afford it. In a make-to-order environment, buffers protect the crucial timeliness of the system. It is evident fromresults of the application; accurate due date performance is possible with shorter lead times andless inventory.7.1. LimitationsThe major limitation is that the model developed herein cannot be, in fact, should not bereplicated in a different environment. Each environment must be analyzed to identify itsconstraint and the drum-buffer-rope model should be applied accordingly. This case howeverpresents a case which is common to most made-to-order apparel manufacturing environments i.e.the T plant structure where a host of products are made in different assembly lines. Any suchenvironment may apply the model described in this paper if its constraint lies in sewing.Another limitation is that the instance of outsourced processes after sewing was notconsidered. It was omitted as at the time of conduction the research since testing a model thatincluded outsourced processes such as garment wash or tie & dye was not possible due to thelimitations of the plant.
  • 777.2. Scope for Further StudyThe limitations described above present an opportunity for further research. The drum-buffer-rope model can be designed to include those instances which require any extra processingother than sewing, finishing and packing. In such a case, the continuity between sewing andfinishing would be broken and a different buffer management strategy would be required.Theory of Constraints provides the power of focus. This enables improvement efforts to bedirected on those areas which would impact the bottom line most. By itself, theory of constraintsis a very high performing system. However, it can pull in elements of Lean, Six Sigma, and SPCetc. in a highly focused and leveraged manner to improve itself. These improvementphilosophies should be applied to the constraint to increase its throughput thus impacting theentire system.A process of ongoing improvement based on theory of constraints might eventually lead tothe constraint shifting into the market. In such a case, market demand will determine thesystem’s  throughput.  When  this  happens,  an  active  internal  bottleneck  might  not  exist.  Then,  an  even simpler application known as Simplified Drum-Buffer-Rope can be applied.Simplified Drum-Buffer-Rope is based on the same concepts as traditional Drum-Buffer-Rope and is certainly in harmony with Theory of Constraints and the Five Focusing Steps. Whatdistinguishes it from traditional Drum-Buffer-Rope is its assumption of market demand as themajor system constraint, even when an internal capacity constraint temporarily emerges.1010 Eli Schragenheim and H. William Dettmer
  • 78In mature apparel manufacturing environments, where stability has been achieved and thesystem’s   throughput   is   not   dominated   by an internal constraint, the Simplified Drum-Buffer-Rope  application  can  be  implemented,  thus  simplifying  the  plant’s  operating  model.
  • 7908. Conclusion
  • 80The Theory of Constraints was developed in a made-to-order environment. There are severalformal Theory of Constraints applications where the detailed body of knowledge is rock-solidand have been applied to hundreds or even thousands of different companies. The productionsolution, which includes the planning and control technique known as Drum-Buffer-Rope can beapplied to any manufacturing business to generate the same outcomes. Hence, the productionsolution is called an application.This leads to the question that why has the theory of constraints not found popularapplication in the apparel manufacturing industry. It may be argued that there is not much to gainfrom it, but such an argument would be grossly inappropriate. As has been illustrated in thispaper, a very simple model applied in an unstable environment of high-mix/low-volume made-to-order apparel manufacturing at an SME in Jaipur led to high due-date performance withshortened lead times and reduced inventories. It was done without complex calculations or largedata collection efforts. This shows that drum-buffer-rope is a simple yet extremely powerful toolto drive apparel manufacturers towards greater profits. Decreased lead times can providecompetitive edge to a company, and assuming there is no constraint in market demand, this couldlead to increased sales. The following co-relations also become true when lead times andinventories are reduced – Cost of inventory which includes costs like warehousing, handling, expedition andworking capital cost goes down. Cost due to sales loss goes down. Extra capacities are released, which reduces un-necessary cost of capital investment. Ongoing improvement projects to improve bottlenecks increase throughput.
  • 81The apparel industry must eliminate its myopic view of focusing on local improvements.Lean and Six Sigma are powerful tools but they must be applied keeping the impact on theglobal system in mind. As has been implied in the paper, the first necessary condition for asustainable lean implementation is stability. This is exactly what Drum-Buffer-Rope provides. Itprovides a schedule that works i.e. it remains valid and keeps the plant pumping out the rightproducts on time to meet delivery schedules despite inaccurate data, absenteeism, machinebreakdown, unreliable vendors, unexpected repair and rework etc.The greatest advantage Theory of Constraints provides is the power or leverage. By focusingon the constraint, the bottom line of the company can be directly affected. No other system, be itLean/JIT, Six Sigma or TQM acknowledges the existence of constraints. But that is never true.Every system must have a constraint since if no constraints existed, the throughput of the systemwould be infinite.This simple acknowledgement of the existence of constraints has huge implications. Itchallenges the very essence of the process of decision making my management. Traditionalmanagement’s  decisions  are  based  on  the  older  cost  accounting  model  which  apportions  all  costs  to products. Here lies a fundamental problem which is addressed comprehensively by thefinancial application of Theory of Constraints known as Throughput Accounting. This basis ofcost allocation always prompts for actions which increase local efficiency. But once theexistence of constraints is acknowledges, the notion of local efficiency loses relevance. Theoryof Constraints prompts focus on global optima instead of local optimum. It has been applied tohundreds of companies and documented evidence exist which showcase dramatic improvements.
  • 82Every system, however complex it might seem, is based on inherent simplicity. The morecomplex a system is, the more it can gain by applying Theory of Constraints. Thus, apparelmanufacturers especially SMEs have much to gain from this body of knowledge.8.1. RecommendationsAny company looking to implement the methods described in this paper must follow thefollowing steps.1. Map the processes of the company.Every plant is different. Hence, no two implementations will be the same. Thus,all the processes from material release to the point of shipment must be mapped.This will illustrate the inter-dependence between the various processes to revealthe supply chain within the plan.2. Identify the constraintSince Drum-Buffer-Rope scheduling is designed on the constraint, the constraintmust first be identified. If the plant employs MRP/ERP systems, this can easily bedetermined comparing the documented capacities of each process. However, sincemost apparel SMEs do not employ such systems, they can simply identify theconstraint by an intuitive analysis of either of the three methods listed below –- Finding the process where waiting time/inventory is highest- The process which cause maximum disruption to downstreamprocesses- Collect data on outputs of each process for a considerable period (amonth or above) to find the process with minimum productivity
  • 833. Exploit the constraintSince the constraint determines the throughput of the system, it must be exploitedto always be productive – doing what is supposed to be done. Each plant will havea different exploitation strategy based on its operating environment. The best wayto exploit the constraint is to write a schedule for the constraint and make surethat it is followed.4. Subordinate everything to the constraintThis is done in order to protect the drum schedule from any variability. The drum-buffer-rope model executes this subordination step by linking the material releaseto the drum schedule. For applying the model, the production buffers must beestablished and buffer management employed as has been described in chapter 5.5. Elevate the constraintElevating the constraint is specific to each system. It should only be undertakenonce the constraint has been subjected to exploitation and subordination phases.Lean/JIT, Six Sigma and TQM may be applied for elevation. Since now theirapplication is properly focused, their benefits would greatly impact the bottom line.
  • 8409. Bibliography
  • 85- Books -Ford, 1922 Ford,   Henry   &   Crowther,   Samuel   “Today   and   Tomorrow”   Doubleday,Page & Co. (1926)Ohno, 1988 Ohno,  T.  “Toyota Production System: Beyond Large-Scale Production.”  Productivity Press (1988)Mabin &Balderstone, 2000Goldratt, 1990Johnson &Kaplan (1987)Cox & Spencer,1998Umble &Srikanth, 1995Senge, 1990Mabin J. Victoria & Steven J. Balderstone “The  world  of  the  theory  of  constraints:  a  review  of  the  international  literature”  CRC Press (2000)Goldratt,  E.  M.  “The haystack syndrome: sifting information out of thedata  ocean.” North River Press (1990)Johnson,  H.  T.,  and  Kaplan,  R.  S.  “Relevance   lost: the rise and fall ofmanagement  accounting.” Harvard Business School Press (1987)Cox,  J.  F.  and  Spencer,  M.  S.  “The  Constraints  Management  Handbook.”  St. Lucie Press (1998)Umble,  M.  and  Srikanth,  M.  L.  “Synchronous  manufacturing:  principles  for world-class  excellence” Spectrum Publishing (1995)Senge,  P.  M.  “The  fifth  discipline:  the  art  &  practice  of  the  learning  organization.” Random House (1990)Goldratt, E.M,1990Goldratt& Cox, 1986Goldratt,1997Stein, 1996Schragenheim &Dettmer, 2000Goldratt,  E.  M.  “What is this thing called Theory of Constraints and howshould  it  be  implemented?” North River Press (1990)Goldratt, E. M.  and  Cox,  J.  “The  Goal  – A Process of OngoingImprovement”  North River Press (1986)Goldratt,  E.  M.  “Critical  chain.” The North River Press (1997)Stein,   R.   E.   “Re-engineering the manufacturing system: applying thetheory  of  constraints  (TOC).” Marcel Dekker (1996)Schragenheim,   E.   and   Dettmer,   H.   W.   “Manufacturing   at   warp   speed:  optimizing   supply   chain   financial   performance.” The St. Lucie Press(2000)
  • 86- Articles -Goldratt, 2009 Goldratt,   E.   M.   “Standing on the Shoulders of Giants: ProductionConcepts versus Production   Applications.”   Gest. Prod. Vol. 16, No. 3(2009)Lee, Hwang,Wang & Lee (2009)Wheatley &Kellner-Rogers, 1999Scheinkopf,1999Umble & Umble,1999- Online Sources -Woeppel, 2000Youngman, 2005Lee, J.H., Hwang, Y.J., Wang, M & Li,  R.K.  “Why  Is  High  Due-DatePerformance So Difficult to Achieve?—An   Experimental   Study”  Production and Inventory Management Journal Vol. 45, No. 1 (2009)sWheatley, M. J. and Kellner-Rogers,   M.   “What   Do   We   Measure   and  Why? Questions About The Uses of Measurement.” Journal for StrategicPerformance Measurement (1999)Scheinkopf,   L.   “Thinking   for   a   change:   putting   the   TOC   thinking  processes   to   use.”   St Lucie Press/APICS series on constraintmanagement (1999)Umble, M. Michael and Umble,  Elisabeth  J.  “Drum-Buffer-Rope forLower  Inventory”  Industrial Management September (1999)Woeppel,  M.  “Introduction  to  Drum-Buffer-Rope”  http://www.pinnacle-strategies.com (2000)Youngman,   K.J.   “A Guide to Implementing the Theory of Constraints(TOC)”  http://www.dbrmfg.co.nz (2005)
  • 87Appendices
  • viAppendix A
  • viiAppendix B
  • viiiAppendix C.1
  • ixAppendix C.2
  • xAppendix C.3
  • xiAppendix C.4
  • xiiAppendix D
  • xiiiAppendix E
  • xivAppendix F
  • xvAppendix G.1
  • xviAppendix G.2
  • xviiAppendix G.3
  • xviiiAppendix G.4
  • xixAppendix G.5
  • xxAppendix G.6
  • xxiAppendix G.7
  • xxiiAppendix G.8
  • xxiiiAppendix G.9
  • xxivAppendix H
  • xxvAppendix I
  • xxviAppendix J.1
  • xxviiAppendix J.2
  • xxviiiAppendix K
  • xxixAnnexures
  • xxxAnnexure 1Training Needs identified for Managers and Supervisors my Method Apparel Consultancy in theNCR region depicting dismal realities.
  • Appendix ASewingTheadCuttingFinishing Packing SewingTheadCuttingFinishing Packing8/3 3902 5412 5501 3810 - - - -9/3 3187 5903 5016 4565 - - - -10/3 2379 4433 4165 3380 3156 5249 4894 3918 Sewing11/3 4335 3249 1440 1260 3300 4528 3540 3068 Packing12/3 6788 3682 3304 1300 4500 3788 2970 1980 Packing13/3 7937 4364 3418 2506 6353 3765 2721 1689 Packing15/3 4664 3887 3218 2000 6463 3978 3313 1935 Packing16/3 3795 4147 6057 4910 5465 4133 4231 3139 Packing17/3 3809 2839 5023 1407 4089 3625 4766 2772 Packing18/3 4552 3445 6454 8552 4052 3477 5845 4956 Thread Cutting19/3 5748 5949 4388 4574 4703 4078 5288 4844 Thread Cutting20/3 7269 4635 5207 1610 5856 4676 5350 4912 Thread Cutting22/3 5063 3680 4456 8533 6027 4755 4684 4906 Finishing23/3 5967 3480 5072 8884 6100 3932 4912 6342 Thread Cutting24/3 3371 4661 1810 1740 4801 3940 3779 6386 Finishing25/3 5934 4142 5322 3940 5091 4094 4068 4855 Finishing26/3 4309 2452 6309 3790 4538 3752 4480 3157 Packing27/3 4139 3750 2777 2810 4794 3448 4803 3513 Thread Cutting29/3 3732 3521 3055 5672 4060 3241 4047 4091 Thread Cutting30/3 3445 2111 3261 1260 3772 3127 3031 3247 Finishing31/3 4410 3379 5376 2403 3863 3004 3897 3112 Thread Cutting1/4 2221 3292 4666 1800 3359 2927 4434 1821 Packing2/4 2763 3156 4897 8580 3131 3276 4980 4261 Sewing3/4 6102 3410 1512 1460 3695 3286 3692 3947 Thread Cutting5/4 2859 3918 3671 6506 3908 3495 3360 5515 Finishing6/4 2019 4806 4790 2210 3660 4045 3324 3392 Finishing7/4 3577 4376 3270 8290 2818 4367 3910 5669 SewingDateOutput of Process 3 Day Moving AverageBottleneck0123456789Sewing Thread Cutting Finishing PackingBottleneck Frequencyvi
  • Appendix BFabric for Body - - - - - Logical FlowRaw Material(Grey Fabric)CuttingSewingThread CuttingFinishingPackingPlant Structure - MAAM Arts, JaipurSolid DyePrint XPrint Y_____ Physical Flow1 Single PrintV/A/T AnalysisThe above structure illustrates the flow of products and processes. Inthis case, the plant has the characteristics of a T-Plant but the Tstructure is not clearly visible.23Mix & Match PrintsSolid DyeProduct TypesOperation Fabric for Liningvii
  • ViiiC
  • Cix
  • CX
  • Cxi
  • Product Types V/A/T Analysis1 Single Print The above structure illustrates the proposed logical flow of productsand processes. Thread cutting as a separate process has beeneliminated and a clear T structure is revealed.2 Mix & Match Prints3 Solid DyeOperation Fabric for Lining - -Solid DyeProposed Logical Plant StructureRaw Material(Grey Fabric)Fabric for Body Constraint OperationSewingPrint YPrint XCuttingDrum 1 Drum 2 Drum 3PackingFinishingAppendix Dxii
  • Appendix ESMVAttaching 9 panels of 8 th Tier 154.64 139.43 135.55 138.65 142.44 141.11 139.44 19.52 158.96 4.31Attaching 5 panels of 7 th Tier 84.01 77.41 71.81 81.51 75.17 78.07 76.79 10.75 87.54 3.53Attaching 3 panels of 6 th Tier 48.70 46.75 51.51 38.25 45.29 46.93 45.75 6.40 52.15 3.45Attaching 3 panels of 5 th Tier 51.03 38.91 47.94 54.58 47.45 47.45 47.27 6.62 53.89 2.85Attaching 2 panels of 4 th Tier 31.76 26.89 32.62 28.44 29.81 28.64 29.28 4.10 33.38 1.62Attaching 2 panels of 3 rd Tier 34.28 39.90 24.14 30.55 31.88 28.53 31.00 4.34 35.34 1.06Attaching 2 panels of 2 nd Tier 26.43 22.68 25.97 23.59 25.27 24.87 24.48 3.43 27.90 1.47Attaching 2 panels of 1 st Tier 21.43 20.48 18.96 19.29 19.55 19.52 19.56 2.74 22.30 0.87Gathering of 8 th Tier 137.32 118.04 121.18 148.53 128.89 129.14 129.15 18.08 147.24 9.92Gathering of 7 th Tier 69.19 59.18 71.38 57.43 66.77 78.52 66.66 9.33 75.99 6.79Gathering of 6 th Tier 73.42 80.68 71.78 46.68 70.20 77.52 69.37 9.71 79.08 5.66Gathering of 5 th Tier 53.43 47.29 46.68 50.69 50.62 50.84 49.23 6.89 56.12 2.69Gathering of 4 th Tier 51.68 50.05 51.36 41.10 48.05 50.86 48.28 6.76 55.04 3.37Gathering of 3 rd Tier 32.91 27.58 32.32 33.59 30.31 32.32 31.23 4.37 35.60 2.69Attachment of 8 th and 7 th Tier 426.88 382.67 370.27 389.27 374.46 377.68 378.87 53.04 431.91 5.03Attachment of 7 th and 6 th Tier 270.36 239.04 230.84 248.75 249.02 233.15 240.16 33.62 273.78 3.42Attachment of 6 th and 5 th Tier 278.92 223.58 212.54 353.35 249.56 216.52 251.11 35.16 286.26 7.35Attachment of 1 st and 2 nd Tier 77.05 69.68 69.35 67.10 67.59 68.01 68.35 9.57 77.91 0.86Attachment of 3 rd and 4 th Tier 97.66 106.24 86.20 85.48 85.67 86.26 89.97 12.60 102.57 4.90Attachment of 2 nd and 3 rd Tier 97.87 80.34 105.21 80.34 86.71 81.89 86.90 12.17 99.06 1.20Attachment of 2 nd and 3 rd Tier 166.13 176.23 160.48 131.62 151.56 120.85 148.15 20.74 168.89 2.75Lining attach 40.03 34.69 61.36 24.91 40.73 27.81 37.90 5.31 43.20 3.18Turn and top stitch of lining 103.92 83.95 93.69 101.29 99.36 105.30 96.72 13.54 110.26 6.34Lining attached to body 77.57 91.02 63.03 61.35 76.89 64.67 71.39 9.99 81.39 3.82Kaccha stitch at sides of waistband 23.10 22.64 16.07 23.60 21.69 22.92 21.38 2.99 24.38 1.27Close belt 55.78 57.66 44.62 53.12 53.83 50.70 51.99 7.28 59.26 3.48Attach belt to waist and hanger loop 93.77 98.41 87.93 78.00 86.36 76.52 85.44 11.96 97.41 3.64Close elastic band 8.71 7.96 8.25 7.98 8.18 7.47 7.97 1.12 9.08 0.37Attach elastic to the body 262.52 263.52 216.17 211.14 230.28 266.16 237.45 33.24 270.70 8.18Top secure stitch on elastic 48.34 41.07 52.62 42.13 42.41 39.49 43.54 6.10 49.64 1.30Label attach ( 2 labels at waist) 60.19 64.08 55.38 48.31 57.02 60.58 57.07 7.99 65.06 4.87Washcare label attach 37.68 39.37 31.55 33.39 36.03 38.29 35.73 5.00 40.73 3.05Bottom hem of lining 99.16 118.55 62.07 78.35 87.86 120.95 93.56 13.10 106.65 7.49SAM 53.26 55.31 2.05VAllowance@ 14%SMVIncrease inTimeReadings (Thread Cut by Operators)Operation Avg. of 3 Readings xAllowance @ 14%I II III IVxiii
  • Appendix F60 * 36 60 * 3653.26 55.31Thread ThreadCutting Cutting800 40041 39No. Rate (Rs.) Cost/Hour No. Rate (Rs.) Cost/Hour36 160 720.00 36 160 720.004 105 52.50 4 105 52.501 250 31.25 1 250 31.251/3 650 27.08 1/3 650 27.081 175 21.88 1 175 21.881/3 650 27.08 1/3 650 27.081/3 175 7.29 1/3 175 7.291/3 175 7.292 105 26.25920.62 887.08Net Profit(Throughput - Operating Expense)102646 123832Eliminating the Thread Cutting department by incorporating thread cutting at source by operators is compared tohaving a separate thread cutting department. They are compared on Lead Time and Costs based on Activity BasedCosting and Throughput Accounting for a hypothetical order.Throughput (Sales-Variable Costs) 199000.00 200000300000 300000Total Operating Expense 96354.50 76167.78Days required 5.55 4.46Operating Expense/Day 17364.99 17096.65Net Profit 102646 123832Hours to make 1000 UnitsComparing Lead Time based on Littles LawActivity Based CostingCost Comparison Based on Throughput Accounting44.39 35.64Floor ClerkThread Cutting ClerkThread Cutting HelperCost for 1000 Units 197354.50 176167.78Sales @ Rs. 300/UnitCost/Unit 197.35 176.1710000 10000Overhead/Minute 20.83 20.83Cost/Minute 36.18 35.62Minutes Produced 2663.41 2138.46Labour Expense/MinuteFactory Overheads/DayCost/Unit14.780Thread Cutting CostCost Component Cost/Unit15.34Thread Cutting at SourceSeparate Thread Cutting DepartmentMeasurementThroughput Rate(Per Hour Output)= 41 = 39800Sewing TotalManufacturing Lead Time(Inventory/Throughput Rate)=Inventory(Average WIP in Thread CuttingDepartment + Inventory in SewingLine)400 400Sewing TotalNil 400 400Direct Material Cost 100.00 100.001020 =Labour ExpenseOperatorsHelpersLine MasterCost Comparison1Floor InchargeQC @ End Line InspectionFloor QCTotal Labour Expense/Hourxiv
  • Appendix G.1Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date QtyBody22-Feb 2980 8-Mar 149 13-Mar 3565 15-Mar 3944 16-Mar 2630 18-Mar 2862 20-Mar 2990 22-Mar 120010-Mar 275917-Mar 1090 19-Mar 1088 22-Mar 920 23-Mar 2400Lining 18-Mar 1015 18-Mar 394422-Feb 690 11-Mar 657 24-Mar 304Net23-Feb 1035.3 18-Mar 1015Packing28-Jan17-MarGrey Issue toPrinting/Dyeing (Mts)Receive Printing (Mts) Print Checking (Mts) Cutting Sewing4500144645 1664 A3904UU76786SmockingBlackLiningAverageThread Cutting FinishingShip DateLead TimeLate DaysProduction TrackStyle #PO #PO DateDue DateSheet #Qty24-Mar31 Days7 DaysFabricBody 72 cm17.5 cmxv
  • Appendix G.2Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date QtyBody19-Feb 2810 26-Feb 923 6-Mar 4375 9-Mar 3720 10-Mar 3720 11-Mar 140 12-Mar 130 19-Mar 368028-Feb 1835Lining 12-Mar 870 13-Mar 87019-Feb 680 26-Feb 66213-Mar 1480 15-Mar 970Net18-Feb 980 26-Feb 955 15-Mar 1190 16-Mar 1700Average Ship Date 24-MarPO # 4500144646 Sheet # 1664 B Body 72 cmStyle # UU76786 Due Date 17-MarWhiteFabricLead Time 36 DaysPO Date 28-Jan Qty 3680 Lining 17.5 cm Late Days 7 DaysProduction TrackGrey Issue toPrinting/Dyeing (Mts)Receive Printing (Mts) Print Checking (Mts) Cutting Sewing Thread Cutting Finishing PackingSmockingxvi
  • Appendix G.3Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date QtyBody19-Feb 3180 28-Feb 3111 12-Mar 4570 13-Mar 4200 13-Mar 1750 16-Mar 1050 17-Mar 1070 20-Mar 424Lining 14-Mar 2444 17-Mar 2400 18-Mar 870 22-Mar 372019-Feb 780 26-Feb 77818-Mar 740 19-Mar 2200Net18-Feb 1080 11-Mar 684Average Ship Date 24-MarPO # 4500144647 Sheet # 1664 C Body 72 cmStyle # UU76786 Due Date 17-MarBlueFabricLead Time 34 DaysPO Date 28-Jan Qty 4144 Lining 17.5 cm Late Days 7 DaysProduction TrackGrey Issue toPrinting/Dyeing (Mts)Receive Printing (Mts) Print Checking (Mts) Cutting Sewing Thread Cutting Finishing PackingSmockingxvii
  • Appendix G.4Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date QtyBody17-Feb 2650 16-Mar 2580 13-Mar 894 18-Mar 3504 18-Mar 2628 19-Mar 873 22-Mar 2240 24-Mar 3328Lining 19-Mar 876 20-Mar 2625 23-Mar 121017-Feb 640 16-Mar 625 17-Mar 3200Net16-Feb 910 13-Mar 894Average Ship Date 24-Mar72 cmFabricLead Time 36 Days17.5 cm Late Days 7 DaysProduction TrackGrey Issue toPrinting/Dyeing (Mts)Receive Printing (Mts) Print Checking (Mts)PO # 4500144649 Sheet # 1664 D BodyStyle # UU76786 Due Date 17-MarLush lawnPO Date 28-Jan Qty 3456 LiningCutting Sewing Thread Cutting Finishing PackingSmockingxviii
  • Appendix G.5Date Qty (Mtrs) Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date QtyBody11-Feb 3220 20-Feb 3125 24-Feb 5051 26-Feb 3200 27-Feb 2685 8-Mar 120 9-Mar 120 18-Mar 3840Lining 26-Feb 1000 28-Feb 1450 9-Mar 420 10-Mar 420 19-Mar 30410-Feb 785 20-Feb 76810-Mar 470 11-Mar 440Net10-Feb 1180 22-Feb 1158 11-Mar 880 12-Mar 88012-Mar 910 13-Mar 91013-Mar 1080 15-Mar 107715-Mar 300 16-Mar 300Average Ship Date 24-MarPO # 4500144651 Sheet # 1664 E Body 72 cmStyle # UU76786 Due Date 17-MarTop - Pink NovaFabricLead Time 42 DaysPO Date 28-Jan Qty 4144 Lining 17.5 cm Late Days 7 DaysProduction TrackGrey Issue toPrinting/Dyeing (Mts)Receive Printing (Mts) Print Checking (Mts) Cutting Sewing Thread Cutting Finishing PackingSmockingxix
  • Appendix G.6Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date QtyBody16-Feb 2780 20-Feb 2698 9-Mar 4298 11-Mar 3720 12-Mar 3720 15-Mar 810 16-Mar 830 13-Mar 1580 20-Mar 1136Lining 16-Mar 2160 18-Mar 900 15-Mar 1419 22-Mar 84817-Feb 680 20-Feb 66217-Mar 730 19-Mar 750 16-Mar 1938 23-Mar 1640Net17-Feb 960 3-Mar 938 22-Mar 1190 17-Mar 1966 24-Mar 5618-Mar 106619-Mar 174820-Mar 281122-Mar 341723-Mar 284124-Mar 4380Average Ship Date 24-MarPO # 4500144653 Sheet # 1664 F Body 72 cmStyle # UU76786 Due Date 17-MarDaisyFabricLead Time 37 DaysPO Date 28-Jan Qty 3680 Lining 17.5 cm Late Days 7 DaysProduction TrackGrey Issue toPrinting/Dyeing (Mts)Receive Printing (Mts) Print Checking (Mts) Cutting Sewing Thread Cutting Finishing PackingSmockingxx
  • Appendix G.7CDate Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date QtyA20-Mar 550 22-Mar 532 27-Mar 2208 29-Mar 1220 6-Apr 213 7-Apr 330 12-Apr 12007-Apr 430 8-Apr 300B20-Mar 580 22-Mar 558 8-Apr 420 10-Apr 5809-Apr 147C20-Mar 1150 22-Mar 111890 cmAverage Ship Date 12-Apr42.5 cmFabricLead Time 24 Days45 cm Late Days 17 DaysProduction TrackGrey Issue toPrinting/Dyeing (Mts)Receive Printing (Mts) Print Checking (Mts)PO # AT91007 Sheet # 1660 A A12002-FebPO Date QtyStyle # AT91007-3 Due Date 27-MarSolid Off WhiteBCutting Sewing Thread Cutting Finishing PackingSmockingxxi
  • Appendix G.8CDate Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date QtyA6-Mar 535 13-Mar 518 29-Mar 2144 31-Mar 1170 3-Apr 85 9-Apr 1158 12-Apr 1150B 5-Apr 3906-Mar 560 13-Mar 5426-Apr 400C6-Mar 1120 13-Mar 1084 7-Apr 29090 cmAverage Ship Date 12-Apr42.5 cmFabricLead Time 38 Days45 cm Late Days 17 DaysABGrey Issue toPrinting/Dyeing (Mts)Receive Printing (Mts) Print Checking (Mts)PO # AT91007 Sheet # 1660 BPO Date 2-Feb Qty 1150Production TrackStyle # AT91007-3 Due Date 27-MarSolid BeigeCutting Sewing Thread Cutting Finishing PackingSmockingxxii
  • Appendix G.9CDate Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date Qty Date QtyA11-Mar 535 27-Mar 514 29-Mar 2146 30-Mar 1170 7-Apr 70 9-Apr 460 9-Apr 580 12-Apr 1150B 8-Apr 390 10-Apr 435 10-Apr 133011-Mar 560 27-Mar 5449-Apr 328 12-Apr 265 12-Apr 1670C10-Mar 1120 27-Mar 1088 10-Apr 378Sewing Thread Cutting Finishing PackingGrey Issue toPrinting/Dyeing (Mts)Receive Printing (Mts) Print Checking (Mts) Cutting Smocking90 cmAverage Ship Date 12-Apr42.5 cmFabricLead Time 32 Days45 cm Late Days 17 daysABPO # AT91007 Sheet # 1660 CPO Date 2-Feb Qty 1150Production TrackStyle # AT91007-3 Due Date 27-MarSolid Moca Brownxxiii
  • C/T Upper 6.39 sec. ,Lining 1.69 sec27,000 x 2 sec availableC/T Upper 36 sec. ,Lining 11.8 sec27,000 x 3 sec availableC/T 3208 sec27,000 x 30 sec.available144 sec.24 days8.08 sec.2 days47.8 sec3 days3208 sec.7 days2Grey Store24 daysC/T 144 sec27,000 x 2 sec.available2 days2Printed fabricchecking3 days3Cutting30Sewing7 days1Thread CuttingC/T 196 sec27,000 sec. available1 day1Pressing¼ daysC/T 43 sec.27,000 sec. available1Checking¼ daysC/T 58 sec.27,000 sec. available5PackingC/T 153 sec.27,000 x 5 sec. available1day43 sec.¼ days58 sec.¼ days153 sec.1 day196 sec1dayProduction lead time(from Grey issue)-14.5 daysProcessing lead time-3857.88 sec.Appendix Hxxiv
  • S M L XL S M L XL S M L XL S M L XL1738 H 1 160 50 100 10 50 100 10 50 100 10 10 20 10 40" 2 300 100 110 90 150 210 100 140 190 90 90 180 90 360" 3 380 90 190 100 240 400 200 140 200 100 100 200 100 400" 4 380 80 200 100 320 600 300 120 200 100 100 200 100 400" 5 380 80 200 100 400 800 400 100 200 100 100 200 100 400" 6 380 100 200 80 500 1000 480 100 200 80 80 160 80 320" 7 380 100 200 80 600 1200 560 120 240 80 80 160 80 320" 8 380 100 190 90 700 1390 650 140 270 90 90 180 90 360" 9 380 100 180 100 800 1570 750 150 270 100 100 200 100 400" 10 400 100 200 100 900 1770 850 150 270 100 100 200 100 400" 11 400 100 200 100 1000 1970 950 150 270 100 100 200 100 400" 12 400 100 200 100 1100 2170 1050 150 270 100 100 200 100 400" 13 400 100 200 100 1200 2370 1150 150 270 100 100 200 100 4001738 H; 1738 G 14 400 100 200 100 1300 2570 1250 150 270 100 100 200 100 4001738 G 15 400 100 200 100 1400 2770 1350 150 270 100 100 200 100 4001738 G; 1732 A 16 400 80 190 130 1480 2960 1480 130 260 130 130 260 130 5201732 A 17 280 60 120 70 30 60 120 70 30 60 120 70 30 30 60 60 30 1801732 A; 1732 B 18 350 55 86 136 73 115 206 206 103 85 146 146 73 73 146 146 73 4381732 B 19 350 48 120 120 60 163 326 326 163 60 120 120 60 60 120 120 60 3601732 B; 1714 A 20 350 43 86 86 43 206 412 412 206 43 86 86 43 43 86 86 43 2581714 A 21 200 50 60 60 30 50 60 60 30 50 60 60 30 30 60 60 30 1801714 A; 1714 B 22 320 37 114 114 57 87 174 174 87 57 114 114 57 57 114 114 57 3421714 B 23 400 74 148 148 74 161 322 322 161 74 148 148 74 74 148 148 74 444Detailed Schedule for Drum IAnnexure J.1xxviTotalSheet #Size Wise Output Cumulative Status at End of Day PackedDay Output
  • S M L XL S M L XL S M L XL S M L XL1738 F 1 160 50 100 10 50 100 10 50 100 10 10 20 10 401738 F 2 300 100 110 90 150 210 100 140 190 90 90 180 90 3601738 F 3 380 90 190 100 240 400 200 140 200 100 100 200 100 4001738 F 4 380 80 200 100 320 600 300 120 200 100 100 200 100 4001738 F 5 380 80 200 100 400 800 400 100 200 100 100 200 100 4001738 F 6 380 100 200 80 500 1000 480 100 200 80 80 160 80 3201738 F 7 380 100 200 80 600 1200 560 120 240 80 80 160 80 3201738 F 8 380 100 190 90 700 1390 650 140 270 90 90 180 90 3601738 F 9 380 100 180 100 800 1570 750 150 270 100 100 200 100 4001738 F; 1738 G 10 380 100 200 100 900 1770 850 150 270 100 100 200 100 4001738 G 11 380 100 200 100 1000 1970 950 150 270 100 100 200 100 4001738 G 12 400 100 200 100 1100 2170 1050 150 270 100 100 200 100 4001738 G 13 400 100 200 100 1200 2370 1150 150 270 100 100 200 100 4001738 G 14 400 100 200 100 1300 2570 1250 150 270 100 100 200 100 4001738 G; 1732 C 15 400 80 190 130 1380 2760 1380 130 260 130 130 260 130 5201732 C 16 280 60 120 70 30 60 120 70 30 60 120 70 30 30 60 60 30 1801732 C; 1732 D 17 350 55 86 136 73 115 206 206 103 85 146 146 73 73 146 146 73 4381732 D 18 350 48 120 120 60 163 326 326 163 60 120 120 60 60 120 120 60 3601732 D 19 350 43 86 86 43 206 412 412 206 43 86 86 43 43 86 86 43 258xxviiSheet # Day OutputSize Wise Output Cumulative Status at End of Day PackedTotalDetail Schedule for Drum IIAnnexure J.2
  • Annexure KDate 22/3 23/3 24/3 25/3 26/3 27/3 29/3 30/3 31/3 1/4 2/4 3/4 5/4 6/4 7/4 8/4 9/4 10/4 12/4 13/4 14/4 15/41732-A 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20Buffer Status 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 851732-B 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20Buffer Status 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 901732-C 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20Buffer Status 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 801732-D 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20Buffer Status 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80Date 16/3 17/3 18/3 19/3 20/3 22/3 23/3 24/3 25/3 26/3 27/3 29/3 30/3 31/3 1/4 2/4 3/4 5/4 6/4 7/4Sheet 1738-H 1 2 3 4 5 6 7 8 9 10Buffer Status 10 20 30 40 50 60 70 80 90 100Sheet 1738-G 1 2 3 4 5 6 7 8 9 10Buffer Status 10 20 30 40 50 60 70Sheet 1738-F 1 2 3 4 5 6 7 8 9 10Buffer Status 10 20 30 40 50 60 70 80 90Date 7/4 8/4 9/4 10/4 12/4 13/4 14/4 15/4 16/4 17/4 19/4 20/41714-A 1 2 3 4 5 6 7 8 9 10Buffer Status 10 20 30 40 50 60 701714-B 1 2 3 4 5 6 7 8 9 10Buffer Status 10 20 30 40 50 60 70 80Lateness = 3 DaysLateness = 0 DaysLateness 2 DaysLateness = 0 DaysLateness = 1 DayLateness = 4 DaysLateness = 2 DaysLateness = 3 DaysLateness = 2 Daysxxviii
  • xxxAnnexure 1Training Needs identified for Managers and Supervisors my Method Apparel Consultancy in theNCR region depicting dismal realities.