Lean Manufacturing and Reliability Concepts Report


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The concepts contained within Lean Manufacturing are not limited merely to production systems. These concepts translate directly into the world of maintenance and reliability.

At the core of Lean Manufacturing philosophy is the concept of elimination of waste. It is about getting precisely the right resources to precisely the right place and at the right time to make only the necessary products in the most efficient manner possible.
The concepts of the elimination of waste can be easily traced to Benjamin Franklin. Poor Richard encouraged the concepts of elimination of waste in numerous ways. Adages like “Waste not, want not”, “A penny
saved is two pence clear…Save and have” and “He that idly loses 5s. [shillings] worth of time, loses 5s., and might as prudently throw 5s. into the river.” Yes, it was Benjamin Franklin that educated us about the possibility that avoiding unnecessary costs could return more profit than simply increasing total sales.

It was Henry Ford who took the concept of the elimination of waste and integrated it into daily operations at his manufacturing facilities. Mr. Ford’s attitude can be seen in his books, “My Life and Work” (1922) and in “Today and Tomorrow” (1926) where he describes the folly of waste and introduces the world to Just-In-Time manufacturing. Mr. Ford cites inspiration from Benjamin Franklin as part of the foundation of these concepts.

However, it wasn’t until Toyota’s Chief Engineer, Taiichi Ohno systematized these concepts and the concept of pull (Kanban) into the Toyota Production System and created a cohesive production philosophy that was focused on the elimination of waste, that the world was able to see the real power of Lean Manufacturing. Interestingly enough, when Mr. Ohno was asked about the inspiration of his system, he merely laughed and said he read most of it in Henry Ford’s book.
Part 1 of this report will focus on one very specific Lean Manufacturing method known as 5S. This section will detail how a 5S initiative focusing on a plant’s Preventive Maintenance (PM) Program can immediately unlock resources within that maintenance department and make the PM process significantly more effective and efficient. Part 2 will look at the Deadly Wastes (Muda) of manufacturing and how elimination of these wastes is also a focus of the reliability process. Part 3 will discuss the overall objectives of Lean Manufacturing and parallel them with the overall objectives of the reliability process. Part 4 will discuss Poka- Yoke (mistake proofing) and see how several standard maintenance techniques are, in fact, Poka-Yoke techniques. A brief discussion of Kaizen and how both Lean Manufacturing and Maintenance and Reliability initiatives share these very same goals and objectives will summarize the entire report.

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Lean Manufacturing and Reliability Concepts Report

  1. 1. From the Reliability Professionals at Allied ReliabilityLean Manufacturing& Reliability Concepts Inside: Key Principles of Lean Manufacturing 3 Types of Inspections for Mistake-Proofing A Must-Read Guide for Maintenance and Reliability Leaders GPAllied © 2010 • 1
  2. 2. Copyright NoticeCopyright 2010 GPAllied. All rights reserved. Any unauthorized use, sharing, reproductionor distribution of these materials by any means, electronic, mechanical, or otherwise is strictlyprohibited. No portion of these materials may be reproduced in any manner whatsoever, withoutthe express written consent of the publisher.To obtain permission, please contact:GPAllied4200 Faber Place DriveCharleston, SC 29405Phone 843-414-5760Fax 843-414-5779info@gpallied.comwww.gpallied.com
  3. 3. Table of Contents Introduction. ............................................................................................ 2 . Part 1: 5S................................................................................................4 Part 2: Muda............................................................................................ 9 Part 3: Key Principles of Lean Manufacturing....................................... 14 Part 4: Poka-Yoke. ................................................................................ 17 . Kaizen................................................................................................... 22 About Allied Reliability........................................................................... 23
  4. 4. Lean Manufacturing and Reliability ConceptsThe concepts contained within Lean Manufacturing arenot limited merely to production systems. These conceptstranslate directly into the world of maintenance andreliability.At the core of Lean Manufacturing philosophy My Life and Work (1922) and in Today andis the concept of elimination of waste. It is Tomorrow (1926) where he describes theabout getting precisely the right resources to folly of waste and introduces the world toprecisely the right place and at the right time to Just-In-Time manufacturing. Mr. Ford citesmake only the necessary products in the most inspiration from Benjamin Franklin as part ofefficient manner possible. the foundation of these concepts.The concepts of the elimination of waste However, it wasn’t until Toyota’s Chiefcan be easily traced to Benjamin Franklin. Engineer, Taiichi Ohno systematized thesePoor Richard encouraged the concepts of concepts and the concept of pull (Kanban) intoelimination of waste in numerous ways. the Toyota Production System and createdAdages like “Waste not, want not”, “A penny a cohesive production philosophy that wassaved is two pence clear…Save and have” and focused on the elimination of waste, that the“He that idly loses 5s. [shillings] worth of time, world was able to see the real power of Leanloses 5s., and might as prudently throw 5s. into Manufacturing. Interestingly enough, when Mr.the river.” Yes, it was Benjamin Franklin that Ohno was asked about the inspiration of hiseducated us about the possibility that avoiding system, he merely laughed and said he readunnecessary costs could return more profit most of it in Henry Ford’s book.than simply increasing total sales. Part 1 of this report will focus on one veryIt was Henry Ford who took the concept of specific Lean Manufacturing method known asthe elimination of waste and integrated it into 5S. This section will detail how a 5S initiativedaily operations at his manufacturing facilities. focusing on a plant’s Preventive MaintenanceMr. Ford’s attitude can be seen in his books (PM) Program can immediately unlock2 • GPAllied © 2010 Lean Manufacturing
  5. 5. resources within that maintenance departmentand make the PM process significantly moreeffective and efficient. Part 2 will look at theDeadly Wastes (Muda) of manufacturing andhow elimination of these wastes is also a focusof the reliability process. Part 3 will discuss theoverall objectives of Lean Manufacturing andparallel them with the overall objectives of thereliability process. Part 4 will discuss Poka-Yoke (mistake proofing) and see how severalstandard maintenance techniques are, in fact,Poka-Yoke techniques. A brief discussion ofKaizen and how both Lean Manufacturing andMaintenance and Reliability initiatives sharethese very same goals and objectives willsummarize the entire report. GPAllied © 2010 • 3
  6. 6. Part 1: 5S5S is the name given to the Lean Lean Application:Manufacturing method for the clearing out The workplace must be arranged in aof all unnecessary things to allow room systematic manner that will encouragefor the acquisition of tools and parts in the efficiency and will reduce unnecessary travelfastest and easiest manner. A comparison and/or motion. Things should be placed whereof 5S methodology with an evaluation and they best meet their functional purpose. (Aoptimization of a PM Program at a plant quickly Second Look At 5S, James Van Patten, Qualityshows how similar these processes are. Progress, October 2006) PM Application:Seiri – Sort (tidiness and/or organize) Another 30% of the tasks contained withinLean Concept: most PM Programs should be reassignedThe workplace is rid of anything that is either to operations or to a lubrication route.unnecessary. Tools and parts are sorted Some of these tasks are generally classified asthrough and only the essential items are kept. “Asset Care” tasks and should be performedEverything else is stored or thrown away. This by an operator. Other general inspection tasksmakes the workplace uncluttered, safer and should be reassigned to operators once theymore organized for productive work. have completed task qualification training.Preventive Maintenance (PM) Application: Lubrication tasks should be reassigned to aStudies agree that somewhere between 30% lubrication route where a trained lubricationand 50% of the tasks in most PM Programs technician can ensure that the task isare non-value added and should be removed. performed to industry best practices standards.These tasks actually cost more to perform than Yet another way to look at this concept withthe benefit they yield. The labor associated regard to ‘order’ is the concept of load levelingwith the completion of these tasks can be the PM tasks, operator care and inspectionreassigned to other maintenance functions like tasks and lubrication tasks. The tasks areworking down the ready backlog. grouped by functional area within the plantSeiton – Straighten (orderliness) and then arranged to insure that each person4 • GPAllied © 2010 Lean Manufacturing
  7. 7. has about the same load or amount of tasks to inspection program is more appropriate.complete and that the tasks are grouped and Condition Monitoring technologies like Infraredarranged to be completed in the most efficient Thermography, Vibration Analysis and Oilmanor possible. Analysis are very powerful tools for just such failure modes and easily pass a cost/benefitSeiso – Shine also Scrub (cleanliness) analysis.Lean Application:The workplace must always be as clean as Seiketsu – Standardizepossible. Waste and trash must be dealt Lean Application:with quickly. Machines must be kept clean Everyone maintains the same basic standardsmaking leaks and other defects more easily for cleanliness in the workplace.recognized. PM Application:PM Application: All of the tasks that remain in the PM ProgramWhen “cleaning out” a PM Program, it should should follow the same standard for format andbe scrubbed of all tasks that do not specifically content. All of the tasks should include a clearaddress a failure mode or do not pass a simple definition of the task, specific steps, necessarycost/benefit analysis. More specifically, it safety warnings, appropriate tools and requiredshould be a failure mode that is appropriate parts. Additionally, the tasks should containfor PM tasks. Weibull analysis of failure data a revision tracking mechanism and shouldshould show a strong Wear Out curve. This have been through a technical review andmeans that it truly is a wear out mechanism approval process. Also, the procedure shouldand a traditional interval based activity or always provide for a feedback mechanismPM should be applied to properly combat it. for the crafts personnel to make suggestionsFailure modes that exhibit a Weibull shape and corrections about the procedure. Thisindicating random failure patterns are not good mechanism creates a continuous improvementcandidates for interval based PM activities. loop for the task procedure.For these failure modes, a comprehensive GPAllied © 2010 • 5
  8. 8. Shitsuke – Systematize, Sustain In creating a systematic, sustainable PM Program, all of the tasks should beLean Application: quantitative in nature with specific, measurableMaintaining a culture of discipline. Workplace activities that detail nominal measurementsstandards are maintained day after day. Once with minimum and/or maximum allowableattained, the workplace is kept safe and limits. PM inspections should require theefficient. use of measurement tools such as calibers,PM Application: micrometers and torque wrenches. “As Found”Creating a culture of discipline in the PM and “As Left” comments should be requiredProgram requires systematizing the program fields and their responses catalogued in theto requiring the tasks be of a nature that not Computerized Maintenance Managementonly encourages craft personnel response but System (CMMS) Program.requires it. PM Programs where the commentsand recommendations of the crafts personnelare not acted on quickly become ineffective.6 • GPAllied © 2010 Lean Manufacturing
  9. 9. Below is a table that summarizes these concepts and shows their inter-connectedness. Allied Reliability Japanese Lean Manufacturing Definition Preventive Maintenance Evaluation “English Translation” (PME) Definition Organized: Distinguish between the Seiri Step 1: Eliminate all non-value added less essential and the necessary.1 “Separate” tasks from the PM. Neat: Put things where the best Seiton Step 2: Reassign appropriate tasks to meet their functional purpose.1 “Straighten” operations or to lubrication routes. Clean: Inspect for and eliminate Seiso Step 3: Eliminate all tasks that do not waste, dirt and damage.1 “Scrub” directly address a specific failure mode. Standardized: Maintain known, Seiketsu Step 4: Insure all remaining tasks follow agreed upon conditions.1 “Standardize” a standardized format including clear definition, specific steps, necessary safety warnings, appropriate tools and required parts. Disciplined: Practice the habit of Shitsuke Step 5: Make sure all tasks are doing what is required even if its “Systematize” quantitative in nature with specific, difficult.1 measurable activities detailing nominal measurements with minimum and maximum allowable limits.1 A Second Look At 5S, James Van Patten, Quality Progress, October 2006Performing a Preventive Maintenance process will identify how many tasks needEvaluation (PME) identifies the amount of to be optimized. A Preventive Maintenancewaste in a PM Program and also helps sort out Optimization (PMO) is the process of revisitingwhich PM tasks can be reassigned to other those tasks that will remain in the PM Programteams within the maintenance and operations and making sure all task procedures aredepartments. It is a very quick and powerful systematic, standardized and contain all ofassessment that can free up some manpower the necessary information for the task to bewithin the maintenance organization to be completed in the most orderly and efficientused for other things. Additionally, the PME manner possible. GPAllied © 2010 • 7
  10. 10. The PME and PMO are a very powerful a specific failure mode and tasks that arecombination of techniques that can be more appropriately assigned to other teamsperformed on a PM Program. Once within the maintenance department or tocompleted, the PM Program will be rid of other departments. Remaining tasks will beunnecessary tasks, tasks that don’t address optimized for efficient completion.The table below details the analysis of a PM Program and the number of craft personnel that can be freedup, reassigned or used for other things like Condition Monitoring. PM Task Action Man-Hours # of Tasks % of Tasks Recommendation Represented Reassign to Operator Care 1,380 6.9% 5,605 Reassign to Lube Route 2,856 14.3% 11,600 Replace with PdM 6,437 32.2% 28,222 Re-Engineer 5,200 26.0% 26,221 No Modifications Required 2,487 10.4% 8,987 Totals 20,000 100.0% 87,297Many maintenance organizations complain is too big, too difficult to manage and doesabout having insufficient manpower to be able not produce any results, i.e. doesn’t reduceto reduce their maintenance backlog. These unplanned downtime. The biggest reason forsame organizations also complain about not this situation is they haven’t applied the 5Shaving enough manpower to staff an internal concept to their PM Program thereby creatingPdM effort. And these same organizations a PM Program that is actually worth keeping.complain about having a PM Program that8 • GPAllied © 2010 Lean Manufacturing
  11. 11. Part 2: Muda Muda is “waste”. In the context of Lean equipment failures. Not realizing the random Manufacturing Muda is the elimination nature of the failures, a sense of frustration of waste and is the core of the Toyota is felt with each emergency repair, so the Production System. In Lean terms, Muda frequency of the time based replacement is refers specifically to waste created by the increased. Maintenance costs continue to rise manufacturing process. In maintenance and failure rates are unaffected. and reliability terms, Muda refers generally Elimination Strategy: to the concept of wasted resources spent in The best way to eradicate this deadly waste is inappropriate maintenance strategies and poor get a better understanding of the true nature of execution of daily maintenance activities. the equipments failure patterns and adjust the Before wastes can be eliminated they must be maintenance strategy to match. identified. And for each type of waste there is a specific strategy surrounding its elimination. Transportation Toyota’s Chief Engineer, Taiichi Ohno, Lean Definition: originally named 7 ‘deadly wastes’ but 2 more Moving products farther than is minimally have since been added. required. Overproduction Maintenance and Reliability Application: The concept of transportation as a waste Lean Definition: in a maintenance context goes directly to Making more than what is needed or making it the amount of time that crafts personnel earlier than needed. spend traveling back and forth between the Maintenance and Reliability Application: job site and the storeroom to retrieve parts An analysis of a typical maintenance that were not kitted, were damaged or were department finds a tremendous amount of not the correct part for the task. Excessive ‘over maintenance’. Traditionally, time based transportation is most often a direct reflection rebuilds or component replacements have of inadequate job planning or incomplete Bill of been used in an effort to combat premature Materials (BOM). GPAllied © 2010 • 9
  12. 12. Elimination Strategy: Elimination Strategy:Improved maintenance job planning and Inter-departmental communication andimproved job plan procedures. Create an coordination must rise to the top of the list ofaccurate BOM for each asset. priorities.Insure parts are stored, maintained andtransported in a manner that does not reduce Inventorytheir life cycle. Lean Definition: Having more inventory than is minimallyWaiting required. Excess Inventory. Deadliest type ofLean Definition: waste.Products waiting on the next production step, Maintenance and Reliability Application:or people waiting for work to do. Organizations who continue to operate in aMaintenance and Reliability Application: reactive manner, never know what is going toWaiting in the maintenance context is very break next. And as such, a large amount ofsimilar. Instead of people waiting for work to spare parts need to be warehoused on-site ordo, it is people waiting to do work. This slight nearby to be available for the next emergency.variation in statements reflects a very common Elimination Strategy:problem for maintenance crafts people. Where The closer an organization moves to athe amount of time spent doing value-added proactive strategy, the fewer and fewerwork (a.k.a. Wrench Time) is low, it is very parts can be kept on hand. As defects aretypical to see a lot of maintenance crafts discovered early and job plans are completedpersonnel standing around and waiting for the early, then the parts can be ordered andopportunity to work. The job is planned and delivered on-time and as-needed instead ofmay in fact be planned well, but the timing with kept in the warehouse.operations was poorly coordinated. The inter-functional coordination was non-existent or atbest disconnected.10 • GPAllied © 2010 Lean Manufacturing
  13. 13. Motion Processing ItselfLean Definition: Lean Definition:People moving or walking more than minimally Stand alone processes that are not linked torequired. upstream or downstream processes. Using complex machines and processes to doMaintenance and Reliability Application: simple tasks.Once again, we find ourselves focused on Not combining tasks to simplify the process,crafts personnel wrench time. Low wrench essentially, ‘processing itself’ = processtime is a major area where improvements simplification.can be seen quickly. Most North Americanmaintenance organizations are surprised to Maintenance and Reliability Application:learn that their wrench time is 20% - 35% An excellent place to see the connectionor less. And even more shocked to learn between Lean and Maintenance and Reliabilitythat Word Class is 55% - 60%. Most people for the concept of “process simplification” isguess that their maintenance crafts personnel the fact that there is no standardization ofaverage 70% and that 95% is possible. parts across like machines. Design engineers love to use the latest and greatest partsElimination Strategy: and designs. If there is truly a competitiveImprovements such as lower overtime and advantage to be had with the new part, thenlower contract labor costs are easily possible like parts in the facility should be upgradedwith improved wrench time. Wrench time as well. If not, then the more standardizedstudies should be scheduled every year to see solution should be chosen at the time ofhow the situation has changed/improved and design. Simply using a different seal orwhat adjustments need to be made to make impeller just because it is new can lead toeven more improvements. Items like improved unnecessary confusion and downtime when aplanning, scheduling and parts kitting can repair is needed. An example might be usingmake huge improvements to a facilities wrench 2 different seals for the same model pump intime %. the same application, when standardizing on GPAllied © 2010 • 11
  14. 14. 1 seal would save time, money and confusion; defects is that an organization has to be ready,most especially when 1 of the seals has willing and able to detect these defects atproven to be a better performer. their earliest stages, immediately begin the planning process to deal with the defect andElimination Strategy: then identify and eliminate the root cause ofMaintainability and parts standardization must the problem. This is the only way sustainablebecome a major focus of design/redesign improvements in productivity and unit cost ofefforts. production can be realized.Defects SafetyLean Definition: Lean Definition:The effort involved in inspecting for and Unsafe work areas creates lost work hours andeliminating defects. expenses.Maintenance and Reliability Application: Maintenance and Reliability Application:For maintenance, defects are the deadliest A decrease in emergency repairs alwaystype of waste. results in a decrease in safety incidents.It is not the presence of defects that plaquean organization, it is how that organization Elimination Strategy:deals with those defects. While the number of And an increase in reliability has proven timedefects can be minimized through methods, and time again to produce a decrease in injurylike precision maintenance techniques, they rates.cannot be completely eliminated. Processes, 100 120 90such as eliminating intrusive inspections and 80 115 Injury Rate (% of Base) 70implementing a Condition Monitoring Program, 110 OEE (% of Base) 60 50 105can make very large impacts on the number of 40 100 30defects present in the asset base. 20 95 10Elimination Strategy: 0 5 10 15 20 25 30 35 40 45 50 55 90The most important point to make about Month Injury Rate OEE12 • GPAllied © 2010 Lean Manufacturing
  15. 15. Information design and performance information. The more incorrect or incomplete the informationLean Definition: is for a given asset, the longer finding theThe age of electronic information and solution to particular problem will take andEnterprise Resource Planning Systems the more uncertain that solution will be upon(ERPS) requires current / correct master delivery. Some of the information that needsdata details. to be current and correct is the machineryMaintenance and Reliability Application: failure data, BOM and machinery name plateMaintenance and reliability people and information.information are part of the resources that need Elimination Strategy:to be planned. Good planning and scheduling A culture of information discipline must beand effective maintenance engineering fostered.relies on complete and correct machinery GPAllied © 2010 • 13
  16. 16. Part 3: Key Principles of Lean ManufacturingA summary of Lean Manufacturing contains 6 KeyPrinciples. It doesn’t take a very detailed analysis to findthat all of these key principles are common to both LeanManufacturing and Maintenance and Reliability.Lean Manufacturing Key Principle #1: how equipment might fail or is expected toPull processing: products are pulled from the fail. The differentiating factor becomes whenconsumer end (demand), not pushed from the this analysis of failure modes and effectsproduction end (Supply). This is Kanban. takes place. It is always to be done before the failures occur. It is something that is doneMaintenance and Reliability: proactively not reactively. While there is anIn the maintenance realm, the concept of ever so slight difference in these 2 concepts,pull is used in the design of the maintenance the implications of this slight difference arestrategy. The potential failure modes of the enormous.equipment and the effects of those failuremodes on that asset’s ability to perform its Lean Manufacturing Key Principle #2:function and on the system at large determine Perfect first-time quality - quest for zerothe maintenance strategy. Failure modes and defects, revealing & solving problems at thetheir effects pull the maintenance strategy into source.existence. The OEM recommendations are Maintenance and Reliability:not pushed as the maintenance strategy of It is the identification and elimination of thechoice. Some people may become confused root cause of machinery defects that drive theat statements like these and infer that the continuous improvement of the maintenancemaintenance strategy is reactive. Nothing strategy. Procedure based organizationscould be further from the truth. Just like use quantitative, documented proceduresKanban is not a reaction to customer demand, for both regular maintenance jobs and theneither is an EMP based on failures. It is PM tasks to drive consistency and qualitybased on failure modes. Failure modes are14 • GPAllied © 2010 Lean Manufacturing
  17. 17. in the maintenance process. Additionally, a 30:1 return on investment that most Norththese same organizations employ precision American facilities have heretofore beenmaintenance techniques to deliver right first unwilling to reach for.time results. The combination of these 3powerful forces has a large impact on the Lean Manufacturing Key Principle #4: Continuous improvement – reducing costs,quest for zero defects. improving quality, increasing productivity andLean Manufacturing Key Principle #3: information sharing.Waste minimization – eliminating all activities Maintenance and Reliability:that do not add value & safety nets, maximize At the core of every good maintenanceuse of scarce resources (capital, people and and reliability person exists the conceptland). of continuous improvement. ContinuousMaintenance and Reliability: improvement is an attitude and a way of30% - 50% of the PM tasks in a typical North life. They are always striving for a betterAmerican maintenance organization are technique, a better designed part, an improvednon-value added tasks. Additionally, most methodology or an easier way to get it done.maintenance organizations operate in a very Every maintenance person looks for a solutionreactive mode and in doing so waste a lot that makes assets easier to maintain and moreof valuable resources. Most studies agree reliable. And every reliability person looks for athat on average, 30% of the labor and 50% solution that makes asset availability and plantof the parts and materials used in unplanned productivity rise and life cycle cost and unitjobs is wasted; not to mention the amount of cost of production go lower.unplanned downtime associated with suchjobs. Those same productivity studies agree Lean Manufacturing Key Principle #5: Flexibility – producing different mixes or greaterthat the combination of these three items diversity of products quickly, without sacrificing(labor, parts and downtime), along with other efficiency at lower volumes of production.benefits (increased safety, decreased sparesinventory, etc.), can account for as much as GPAllied © 2010 • 15
  18. 18. Maintenance and Reliability: Maintenance and Reliability:Flexibility is the key to keeping up with the In the sentence above, simply replace thechanging business environment. It is no word ‘suppliers’ with the word ‘operations’.different for maintenance and reliability. As Now it reads: Building and maintaining a longthe market changes, so does the mix of term relationship with operations throughproducts and volume. While the core function collaborative risk sharing, cost sharingof a manufacturing facility rarely changes, and information sharing arrangements. Athe requirements for its operation do change partnership must be established betweenand consequently the reliability and criticality maintenance and operations. And, as withof different machines can change almost any true partnership, it must be born of mutualon a daily basis. The onus is then on the respect and the attainment of common goals.maintenance and reliability function of a facility A partnership that is based on ‘winning andto create systems and processes, whereby, losing’, or an attitude of “This is my plant andchanges in the market place do not create you work for me!”, is destined for failure or atsuch drastic changes in the daily execution of best, mediocrity.the maintenance process that the process itselfbecomes dysfunctional.Lean Manufacturing Key Principle #6:Building and maintaining a long termrelationship with suppliers throughcollaborative risk sharing, cost sharing andinformation sharing arrangements.16 • GPAllied © 2010 Lean Manufacturing
  19. 19. Part 4: Poka-Yoke Poka-Yoke was first introduced at the Toyota defects if worker errors are discovered and Motor Corporation in 1961 by Shigeo Shingo, eliminated beforehand”. Additionally, he stated, one of their industrial engineers. Originally “Defects arise because errors are made; the named Baka-Yoke, ‘fool-proofing’ or ‘idiot- two have a cause-and-effect relationship”. proofing’, the name was changed to Poka- Statistical analysis of machinery failures Yoke or ‘mistake-proofing’ in 1963 for want of a reflects essentially the same scenario. RCM more honorable and less offensive name. studies from the 60’s and 70’s have shown Poka-Yoke can take the form of a mechanism that as much as 68% of failure modes designed to ensure that proper conditions detected in machinery are the result of poor exist before a process step occurs, thereby maintenance and/or operating procedures; and preventing a defect from occurring. Poka-Yoke another 14% are the result of random events can also be a procedure designed to identify caused by people’s carelessness. Add to this and/or eliminate defects as early as possible another 7% for wear-in failures and a total of in the process. Essentially, Poka-Yoke is the 89% of the failures are the result of people’s concept of easily and quickly detecting and lack of attention to detail or an incomplete removing defects. There are many parallels understanding of their operations. This leaves between Lean Manufacturing and Maintenance only 11% of the failure modes to be the result and Reliability with respect to Poka-Yoke. of age, wear and fatigue. Studies from the The concept of detecting and removing 80’s and 90’s reflect that proper attention to defects is the very heart of maintenance and procedures dropped the previously reported reliability efforts; and any technique that helps 68% to as low as 6%, but the 14% from accomplish this easier, quicker or earlier in the random events climbed to as high as 25%. So, process is a Poka-Yoke technique. while improving maintenance and operating In explaining the origin of defects Shingo said, procedures did lower the instances of infant “The causes of defects lie in worker errors, mortality, carelessness in other areas related and defects are the results of neglecting those to operations didn’t improve. errors. It follows that mistakes will not turn into GPAllied © 2010 • 17
  20. 20. Three different types of inspections were explained fact that defects occur in your systems andby Shingo in the concept of Poka-Yoke. that you are able to successfully identify and eliminate them. You must move further backJudgment Inspection in the process to identify them and eliminateJudgment inspection was identifying defective them at their source.products or material after the completion of the Yet another way that Condition Monitoring isprocess, essentially finding the defect when considered a judgment inspection is in its useit is too late. Shingo warned that relying on as a troubleshooting tool. Organizations thatthis method isn’t effective quality management do not use Condition Monitoring technologiesand therefore, judgment inspections should have to rely on the traditional troubleshootingbe avoided when possible. Maintenance techniques such as trial and error, disassemblyand reliability personnel sometimes have no and parts replacement. Utilizing Conditionchoice but to utilize this method of defect Monitoring technologies can give the craftsdetection as it is not manufacturing defects, person a tremendous amount of informationbut machinery defects that are being sought. before the job is begun. Things like gearBest practices organizations use Condition problems, electrical problems in motors andMonitoring technologies like Vibration Analysis, contaminant ingression can be highlighted andInfrared Thermography and Oil Analysis to detailed before the machine itself is ever shutidentify machinery defects. While there are down.some benefits to identifying these defects and Using Condition Monitoring to help withhandling them in a proactive manner, the real troubleshooting and to help identify the rootbenefit lies in using these Condition Monitoring cause of machinery defects, makes Conditiontechnologies to help identify and eliminate the Monitoring itself a very powerful judgmentroot cause of these defects. Not using these inspection Poka-Yoke technique.technologies to help eliminate the root causeof defects was the type of inspections thatShingo and the rest of the quality culture werewarning against. Do not be satisfied with the18 • GPAllied © 2010 Lean Manufacturing
  21. 21. Informative Inspection ‘defect’ that the inspection process is detectingThe 2nd type of inspection in the Poka-Yoke is an inadequate maintenance strategy.system is the informative inspection. This type Many organizations believe that using theof inspection is used to prevent defects though Mean Time Between Failure (MTBF) as theutilizing data gathered from the inspection proper interval for time based replacementsprocess. The most common example of an and/or overhauls is the best method to costinformative inspection is the use of statistical effectively prevent unplanned downtime. Thisprocess control. Dr. Shingo offered two is not correct and results in higher costs thandifferent types of informative inspection. The necessary. Weibull analysis shows that for afirst method was for the very next station in group of machines, by the time the MTBF isthe manufacturing line to perform a quality reached, 63.21% of the machines have alreadycheck or defect inspection on the material that failed.just came from the previous station. While The better type of informative inspection wouldthis method was reliable and cost effective, be to use failure data to populate a Weibullthe second method of informative inspection analysis model for the machine or system andreduces the time and cost of the additional let the analysis show the most cost effectiveinspection to almost zero, and that was to time to perform the maintenance action. In thehave the each station perform a pre and post absence of a comprehensive failure history, aprocess inspection. Thereby simultaneously single failure point and some local knowledgechecking the quality from the previous station about the frequency and types of failures canand checking the quality of their work before lead to some excellent approximations of thesending it to the next station. actual Weibull shape. This method is knownFrom a maintenance and reliability as Weibayes and is a very powerful technique.perspective, an example of using this type of In using the failure data that comes into theinformative inspection would be performing CMMS system on a daily basis to keep theWeibull analysis to constantly adjust the failure modes library and Weibull analysesmaintenance strategy for a piece of equipment up-to-date, the maintenance strategies canor system within the plant. In doing so, the be adjusted as more detailed information GPAllied © 2010 • 19
  22. 22. becomes apparent. Using statistical analysis bearing component life (in the absence of in this way makes Weibull analysis an other issues).extremely effective informative inspection • All rotating equipment will be aligned to Poka-Yoke technique. <0.5 mils/inch. Just like the balance standard, this is tighter than most alignment Source Inspection standards and will lead to much lower radial The third and final type of Poka-Yoke and axial loading on the bearing and inspection is the source inspection. Source therefore longer bearing life.inspection is the inspection of an operating • Milling the bottom of all cast frame motor environment or materials before the production feet so that they are all flat and co-planar. process begins to ensure that the proper This technique makes the alignment conditions exist. Source inspections in the process quicker and easier. It also helps maintenance and reliability arena are very prevent a condition called soft-foot which common. They take at least three forms when leads to warped motor frames, high considered in the context of machinery repairs. frequency vibration in the motor bearings Precision maintenance techniques are a type and reduced bearing life.of source inspection. Precision maintenance • All electrical connections will be installed technique is defined as any technique that using torque wrenches and will be torqued makes the likelihood of extended defect free to manufacturer’s specifications. Contrary operation more possible. Some examples to popular belief, tighter isn’t necessarily of precision maintenance and reliability better. Some types of electrical techniques might include: connections can be too tight. This spreads • All rotating equipment will be balanced the individual strand of wire out more and in-place to a minimum standard of 0.05 creates the very problem that was trying to inches per second. This is significantly be avoided, a high resistance connection. lower than most balance standards but • All lubricant will be removed from the bulk not impossible. This tighter balance container and placed into lubricant standard would lead to measurably longer reservoirs via filter carts with a 3 micron 20 • GPAllied © 2010 Lean Manufacturing
  23. 23. filter. This prevents solid contaminants of the procedure. A technical review and from being introduced into the machinery approval process ensures that all procedures reservoir that would be detrimental to asset are correct and up-to-date. As these health. procedures are designed to help eliminate theBy no means a comprehensive listing, possibility of a workmanship defect during athese are just a few examples of precision repair or inspection, it is a source inspectionmaintenance techniques. Using these Poka-Yoke technique.techniques extends the amount of time Another type of source inspection Poka-Yokebetween machine commissioning and the technique is the use of Condition Monitoringpoint of defect ingression. As such, they are as a post repair commissioning inspection.techniques that ensure the proper conditions Technologies like Vibration Analysis, Structure-are present for defect free operation and are Borne Ultrasound, Infrared Thermographytherefore a type of source inspection Poka- and Motor Circuit Analysis are all excellentYoke technique. tools to certify repairs and new installations.The most comprehensive source inspection Should workmanship defects like inadequatePoka-Yoke technique is the use of procedures alignment or the presence of a bearing faultwhen performing machine repairs and due to improper installation be identified,inspections. Even with the most skilled then the defect can be corrected beforecrafts personnel, mistakes are made, steps the machine is returned to service. Usingare skipped and conditions are overlooked. Condition Monitoring technologies can helpA technically accurate, well constructed easily identify defects or conditions that willprocedure decreases the conditional cause defects early in the process and isprobability of a mistake being made. A therefore a source inspection Poka-Yokefeedback loop from the crafts person to the technique.planner ensures the continuous refinement GPAllied © 2010 • 21
  24. 24. Kaizen‘Continuous Improvement’ is the translation Manufacturing is managed on a dailymost often used for the Japanese word basis. Kaizen is also the attitude with whichKaizen. Contrary to the popular use of the maintenance and reliability people operate onterm, Kaizen is not an event. Kaizen is a a daily basis. Just a few examples include:frame of mind or the attitude with which you • Improving maintenance job plans so address things. It means always looking at that the number of side trips a crafts a situation with what martial arts instructors person has to make to acquire parts, refer to as Shoshin, which means “first materials and permits approaches zero.mind” or “a beginner’s mind”. Beginners • Improving the written maintenance are always learning. With each moment procedures so that everyone regardless of learning, improvements are made. With of specific experience with that plant or each improvement, more learning is desired machine knows the proper steps to affect so that more improvements can be made. the repair.This becomes a continuous cycle. With • Improving the inspection process to more learning comes more improvements. identify defects closer to their point of The moment learning ceases is the moment inception thereby giving the planning improvement ceases. The moment function more time to adequately deal improvement ceases is the moment your with the problem.competitors start to gain ground. The term • Improving the operations of the plant to ‘expert’ bears the connotation of “nothing left produce fewer and fewer variations in the to learn”. In an environment that embraces process.Kaizen there is no such thing as an expert. Numerous other examples could be cited,Just like Kaizen, concepts like 5S, Kanban, but suffice it to say the concepts of LeanPoka-Yoke and Muda are not single events, and the concepts of improved maintenancethey are concepts that are practiced on a and reliability go hand-in-hand. It is not justdaily basis. Kaizen is an attitude; it is a difficult to separate these concepts, it is quiteway of life. It is the style with which Lean frankly, impossible.22 • GPAllied © 2010 Lean Manufacturing
  25. 25. About Allied Reliability Founded in 1997, Allied Reliability and Allied Services Group have quickly become the largest maintenance and reliability engineering firm specializing in Predictive Maintenance and Condition Monitoring services. Today, Allied serves clients in over 200 plants and facilities in 40 states in the U.S., 3 provinces in Canada, plus countries in Europe and Latin America. Allied technicians routinely monitor over 150,000 pieces of equipment with a full range of PdM technologies. For more information about our Consulting and Training offerings listed below, e-mail us at info@alliedreliability.com or call 1-888-414-5760: PM / PdM Program Design Reliability Engineering Services • Criticality Analysis • Reliability Centered Maintenance (RCM) • PM Evaluation • Root Cause Analysis (RCA) • Asset Health Matrix • Failure Modes and Effects Analysis (FMEA) • PdM Technologies Evaluation • Life Cycle Costing (LCC) • Work Management Evaluation • Availability Simulation and Modeling • Contract PdM • Weibull Analysis • Remote Diagnostics • Coaching and Mentoring GPAllied © 2010 • 23
  26. 26. Legal Notice While all attempts have been made to verify information provided in this publication, neither the author nor the publisher assumes any responsibility for errors, omissions or contradictory interpretation of the subject matter herein. The purchaser or reader of this publication assumes responsibility for the use of these materials and information. Adherence to all applicable laws and regulations, including federal, state and local governing business practices and any other aspects of doing business in the U.S. or any other jurisdiction is the sole responsibility of the purchaser or reader. GPAllied assumes no responsibility or liability whatsoever on behalf of any purchaser or reader of these materials.24 • GPAllied © 2010 Lean Manufacturing
  27. 27. GPAllied4200 Faber Place Drive | Charleston, SC 29405 www.gpallied.com o. 888-414-5760 | f. 843-414-5779