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  2. 2.  product design is the process of deciding on the unique characteristics and features of the company’s product.
  3. 3. PRODUCT AND SERVICE DESIGN  What does Product and service design do?  The various activities and responsibilities of Product and service design include  Translate the customer wants and needs into product and service requirements  Refine existing products and services (marketing)
  4. 4. PRODUCT ANDSERVICE DESIGN  Develop new products and/or services( marketing and operation)  Formulate quality goals ( marketing and operation)  Formulate cost targets (accounting ,finance and operations)  Construct and test prototype ( marketing , operations, engineering)
  5. 5. REASONS FOR PRODUCT AND SERVICE DESIGNOR REDESIGN  Product and service design has typically had strategic implications for the success and prosperity of an organization .  Organization become involved in Product and service design or redesign for a variety of reasons  The main forces that initiate design or redesign are marketing opportunities and threats
  6. 6. REASONS FOR PRODUCT AND SERVICE DESIGNOR REDESIGN  The factors that give rise to market opportunities and threats can be one or more changes
  7. 7. VALUE ANALYSIS  Refers to an examination of the function of parts and materials in an effort to reduce cost and improve performance of a product.
  8. 8. OBJECTIVES OF PRODUCT ANDSERVICE DESIGN  The main focus of Product and service design is customers satisfaction.  Hence ,it is essential for designers to understand what the customer wants and design with that in mind.  Secondary focuses in Product and service design relate to function, cost, potential profit, quality, appearance, forecasted value
  9. 9.  Ease of production, ease of assembly and ease of maintenance or service.  In general ,design ,operations and marketing must work closely together ,keeping each other informed and taking in to account the wants and needs of the customer.
  10. 10.  In addition , legal, environmental and ethical considerations can influence the design function.
  11. 11. OTHER ISSUES IN PRODUCT AND SERVICE DESIGN  Aside from legal, environmental and ethical consideration , designers must also take into account  Products or services life cycles  How much standardization to incorporated  Product or service reliability
  12. 12. LIFE CYCLES  Many new product and service go though a life cycles in terms of demand.  When an item is introduced, it may be treated as a curiosity  Demand is generally low because potential buyers are not yet familiar with the item  Many potential buyers recognize that all of the bugs have probably not been worked out
  13. 13. LIFE CYCLES  And that the price drop after the introductory period  Capacity and processing are design for low volume  With the passage of time, design improvements usually create a more reliable and less costly output.  Demand then grows for these reasons,
  14. 14. LIFE CYCLES  And because of increasing awareness of the product or service  High volume will involve different methods and contribute to low costs.  At the next stage in the life cycle, product or service reaches maturity: there are few, if any, design changes and demand levels off
  15. 15. LIFE CYCLES  Eventually ,the markets becomes saturated, which leads to a decline in demand
  16. 16. STANDARDIZATION  Standardization is  Extent to which there is absence of variety in a product, services or process  Standardized products are made in large quantities of identical items  Standardization carries a number of important benefits as well as certain disadvantage
  17. 17. STANDARDIZATION  Standardized products are immediately available to customers  Standardized products mean interchangeable parts, which greatly lower the cost of production higher  While increase productivity and making replacement or repair relatively easy compared with that of customized  Design costs are generally lower
  18. 18. STANDARDIZATION  Another benefit of Standardization is reduced time and cost to train employees and reduced time to design jobs.  Lack of Standardization is at times leads to serious difficulties and competitive struggles  High cost of design changes increases resistance to improvements  Decreased variety results in less consumer appeal
  19. 19. DESIGNING FOR MASS CUSTOMIZATION  Companies like standardization because it enables them to produce high volumes of relatively low-cost products, albeit product with little variety  Customers, on the other hand,  Typically prefer more variety , although they like the low cost.
  20. 20. DESIGNING FOR MASS CUSTOMIZATION  The question for producers is to resolve these issues without 1) Losing the benefits standardisation and 2) Incurring a host of problems that are often linked to variety These include increasing the resource needed to achieve design variety
  21. 21. DESIGNING FOR MASS CUSTOMIZATION  increasing variety in production process, which would add to the skills necessary to produce the products  Causing a decrease in productivity  The answer , at least for some mass customization, a strategy of producing standardized goods or services, but incorporating some degree of customization
  22. 22. PHASES IN PRODUCT DESIGN AND DEVELOPMENT  product design and development generally proceeds in a series of phases Idea generation  Product development begins with Idea generation  Ideals can come from a variety sources. They can be
  23. 23. IDEA GENERATION  Supply chain based  Competitor based  Research based  a Supply chain can be a rich source of ideas.  Customers, suppliers, distributors, employees, and maintenance and repair personnel can provide valuable insight.
  24. 24. IDEA GENERATION  One of the strongest motivators for new and improved products or services is competitors' product and services  by studying a competitors' product and services and how the competitor operates  Pricing policies, return policies, warranties. Location strategies etc an organization can glean many ideals
  25. 25. IDEA GENERATION  Some companies purchase a competitor’s product and then carefully dismantle and inspect it, searching for ways to improve their own product, this is called reverse engineering
  26. 26. FEASIBILITY ANALYSIS  Feasibility analysis: entail  marketing analysis(demand),  economic analysis (development cost and production cost ,profit potential and  Technical analysis, capacity requirements and availability and the skills needed
  27. 27. 2 PRODUCT SPECIFICATIONS  This involves detailed descriptions of what is needed to meet(or exceed) customer wants  3 process specifications  Once Product specifications have been set, attention turns to specifications for the process that will be needed to produce the product
  28. 28. CONT---  Alternatives must be weighted in terms of cost, Availability of resource, potential profit and quality  This involves collaboration between accounting and operations  4 prototype development.  With Product and process specifications complete,
  29. 29. CONT---  One( or a few) units are made to see if there are any problems With the Product or process specifications  5 Design review  Make any necessary changes or abandon  involves collaboration among marketing, engineering, design, accounting and operations
  30. 30. 6 MARKET TEST  A market test is used to determine the extent of customer acceptance.  If unsuccessful return to the Design review. This phase is handled by marketing  7 product introduction. Promote the product.  This phase is handled by marketing  8 follow-up evaluation
  31. 31. PROCESS SELECTION  Technology  Technology and Technological innovation often have a major influence on business organization  Technological innovation refers to the discovery and development of new or improved product or services or process for producing or providing them
  32. 32. CONT--  Processes converts inputs into output  Process selection refers to deciding on the way production of goods or services will be organized  It has a major implication for capacity planning, layout of facilities, equipments and design of work systems
  33. 33.  Process selection occurs as a matter of course when new products or services are being planning.  However ,it also occurs periodically due to changes in product or equipments , as well as competitive pressure
  34. 34.  Forecasting , product or service design and technological consideration all influence capacity planning and process selection.  How an organization approaches process selection is determined by the organization’s process strategy. Key aspect include  Capital intensity
  35. 35. Forecasting Product and Service Design Technological Change Capacity Planning Process Selection Facilities and Equipment Layout Work Design PROCESS SELECTION AND SYSTEM DESIGN
  36. 36.  Technology  The application of scientific discoveries to the development and improvement of product and services and operations processes  There are different kinds technology. Operations management is primary concerned with three technology
  37. 37.  1product and service technology is the discoveries and development of new product and services.  This is done mainly by researchers and engineers, who use the scientific approach to develop new knowledge and translate that into commercial application
  38. 38.  Process technology  Information technology
  39. 39. PROCESS SELECTION  The three questions bear on Process selection 1) how much variety in products or services will the system need to handle 2) what degree of the equipment flexibility will be needed 3 what is the expected volume of out put  Answers to these questions will serve as a guide to selecting an appropriate process
  40. 40. PROCESS TYPES  There are five basic process types  Job shop  Batch  Repetitive  Continuous and project
  41. 41. JOB SHOP  Usually operated in small scale  It is used when low volume  High variety goods or services will be needed  Process is intermittent  Work includes small jobs, each with somewhat different processing requirements.
  42. 42. BATCH  Batch processing is used when moderate volume of goods or services is desired and  It can handle a moderate variety in goods or services  The equipment need not be as flexible as in job shop, but processing is still intermittent  The skill level of work doesn’t need to be as high as a job shop because there is less variety
  43. 43. BATCH  In the jobs being processed  Examples of batch systems include bakeries, which make bread, cakes in batches,  movie theatres, which show movies to groups(batches) of people and  Airlines , which carry planeloads(batches) of from airport to airport
  44. 44. BATCH  Soft drinks  Beer, magazines and books
  45. 45. REPETITIVE  When higher volumes of more standardized goods or services are needed, Repetitive processing is used.  The standardized output means only slight flexibility of equipment is needed  Skill of workers is generally low  Examples of this types of system include  Production line and assembly lines
  46. 46. CONTINUOUS  When a higher volumes of non-discrete, highly standardized output is desired, a continuous system is used.  These systems have almost no variety in output and, hence, no need for equipment flexibility  Worker skill ranges
  47. 47. STRATEGIC CAPACITY PLANNING  Capacity refers to upper limit or ceiling on the load that an operating unit can handle.  The load might be in terms of the number of physical units produced (e.g.- , bicycles assembled) or the number of services performed (e.g., computers upgraded per hours)
  48. 48. STRATEGIC CAPACITY PLANNING  The goal of Strategic Capacity Planning is to achieve a match between the long- term supply capabilities of an organization and the predicted level of long-term demand.  Organizations become involved in Capacity Planning for various reasons.  Among the chief reasons are:
  49. 49. REASONS FOR STRATEGIC CAPACITY PLANNING  Changes in demand  Changes in technology  Changes in environment and  Perceived Threats or opportunities A gap between current and desired capacity will result in capacity that is out of balance.
  50. 50. STRATEGIC CAPACITY PLANNING  Overcapacity cause operating costs that are too high  While under capacity causes strained resources and possible loss of customers.  Some basic questions in Capacity Planning are the following
  51. 51. QUESTIONS IN CAPACITY PLANNING  What kind of capacity is needed?  How much is needed?  When is it needed?  The question What kind of capacity is needed depends on the products and services that management intends to produce or provide.
  52. 52. QUESTIONS IN CAPACITY PLANNING  Forecasts are key inputs used to answer questions How much is needed and when is it needed
  53. 53. CAPACITY DECISIONS ARE STRATEGIC  For a number of reasons, Capacity decisions are among the most fundamental of all the design decisions that managers must make  Capacity decisions can be critical for an organization 1) Capacity decisions have real impact on the ability of the organization to meet future demand for products or services
  54. 54. CAPACITY DECISIONS ARE STRATEGIC 2) Capacity decisions affects operating costs 3) Capacity is usually a major determinant of initial cost 4) Capacity decisions often involve long-term commitment of resources and the fact that, once they are implemented, those decisions may be difficult or impossible to modify without incurring major costs
  55. 55. CAPACITY DECISIONS ARE STRATEGIC 5)Capacity decisions can affect competitiveness 6)Capacity affects the ease of management
  56. 56. DEFINING AND MEASURING CAPACITY  No single measure of capacity will be appropriate in every situation .rather ,the measure of capacity must be tailored to the situation.  Commonly used measure of capacity are:  Design capacity  The maximum output rate or service capacity an operation, process, or facility is designed for
  57. 57. MEASURING CAPACITY  Effective capacity  Design capacity minus allowances such as personal time, maintenance and scrap  Design capacity is the maximum output rate achieved under ideal conditions  Effective capacity is usually less than design capacity owing to realities of changing product mix, the need for periodic maintenance of
  58. 58. MEASURING CAPACITY  Equipment ,lunch breaks, coffee breaks, problems in scheduling and balancing operations and similar circumstances.  Actual output cannot exceed effective capacity and is often less than because of machine breakdowns, absenteeism, shortages of materials and quality problems , as well as factors that are outside the control of the operations managers
  59. 59. MEASURING CAPACITY  These different measures of capacity are useful in defining two measures of system effectiveness:  Efficiency and utilization  Efficiency=actual output  effective capacity  Utilization=actual output design capacity
  60. 60. MEASURING CAPACITY  Both measures are expressed as percentages  Given the following information, compute the Efficiency and the utilization of the vehicle repair department  Design capacity= 50 trucks per day  Effective capacity= 40 trucks day  Actual output =36 trucks per day 
  61. 61. DETERMINANT OF EFFECTIVE CAPACITY  Facilities  The design Facilities, including size and provision for expansion, is key.  Location factors, such tra.c,distance to mkt,labour s. energey sources and room for expansion  Layout, env’ta factors  Product and service factors  Product or service design can have tremendous influence on capacity.
  62. 62. DETERMINANT OF EFFECTIVE CAPACITY  Process factors  The quantity capacity of a process is an obvious determinant of capacity  Eg. If the quality of output does not meet standards , the rate of output will be slowed by the need for inspection and rework activities  Productivity also affects capacity
  63. 63.  Process improvements that increase quality and Productivity can result in increased capacity  Human factor  Policy factor  Management policy can affect capacity by allowing or not allowing capacity options such as over time, second or third shifts
  64. 64. STEPS IN THE CAPACITY PLANNING PROCESS 1. Estimate future capacity requirements 2. Evaluate existing capacity and facilities and identify gaps 3. Identify alternatives for meeting requirements 4. Conduct financial analyses of each alternatives 5. Assess key qualitative issues for each alternatives
  65. 65. 6.Select the alternative to pursue that will be best in the long term 7.Impement the selected alternative 8. Monitoring results
  66. 66. FORECASTING CAPACITY REQUIREMENTS  Capacity planning decisions involve long – term and short-term considerations  involve long –term considerations relate to overall level of capacity, such as facility size  involve short-term considerations relate to probable variations in capacity requirements created by such things as seasonal, random and irregular fluctuations in demand
  67. 67. FORECASTING CAPACITY REQUIREMENTS  long –term capacity needs require forecasting demand over a time horizon and then converting those forecasts into capacity requirements  Some basic demand patterns that might to identified by a forecast.  In addition to basic patterns there are more complex patterns, such as combinations of cycles and trend
  68. 68. FORECASTING CAPACITY REQUIREMENTS  When trends are identified, the fundamental issues are 1. How long the trend might persist, because few things last forever and 2. The slope of the trend If cycles are identified, interest focus on 1) The approximate length of the cycles 2) The amplitude of the cycles(i.e deviation from the average)
  69. 69. CALCULATING PROCESSING REQUIREMENTS  A necessary piece of information is the capacity requirements of products that will be processed.  To get this information, one must have reasonable accurate demand forecasts for each product and  know the standard processing time per unit for each product, the number of workdays per year
  70. 70. CALCULATING PROCESSING REQUIREMENTS  And the number of shifts that will be used .  A department works one 8-hours shifts, 250 days a year, and has these figures for usage of a machine that is currently being considered.
  71. 71. CALCULATING PROCESSING REQUIREMENTS product Annual demand Standard processi ng time per unit(hr) Processi ng time needed( Hr) 1 400 5 2,000 2 300 8 2,400 3 700 2 1,400 5,800
  72. 72. CALCULATING PROCESSING REQUIREMENTS  Working one 8-hours shifts 250 days a year provides an annual capacity of 8 *250=2,000 hours per year.  We can see that three of these machines would be needed to handle the required volume:  5800 hours = 2.9 machines 2000 hours/machine
  73. 73. THE CHALLENGES OF PLANNING SERVICE CAPACITY  It is important to note that capacity planning for services can present special challenges due to its nature of services  Three very important factors in planning services capacity are 1) The need to be near customers 2) The inability to store services 3) The degree of volatility of demand
  74. 74. MAKE OR BUY  Once capacity have been determined, the organization must be decided whether to produce a good or provided a service itself, or to outsource(buy) from another organization.  Many organizations buy parts or contract out services, for a variety of reasons.  Among those factors are  1 available capacity
  75. 75. MAKE OR BUY  2) Expertise. If a firm lacks the Expertise to do a job satisfactorily, buying might be a reasonable alternative  3)quality considerations  4) the nature of demand  5) cost  6) risk. Outsourcing may involve certain risks. One is loss of control over operations.
  76. 76. MAKE OR BUY  Another is the need to disclose proprietary information
  77. 77. DEVELOPING CAPACITY ALTERNATIVES  Aside from the general considerations about the development of alternatives (i.e .,conduct a reasonable search for possible alternatives, take care not over-look nonquantitative factors),there are other things that can be done to enhance capacity management.
  78. 78. DEVELOPING CAPACITY ALTERNATIVES 1. Design flexibility in to the system The long-term nature of many capacity decisions and the risk inherent in long-term forecasts suggest potential benefits from reigning flexible systems. 2. Take stage of life cycle into account. Capacity requirements are often closely linked to the stage of life cycle that a service or product is in
  79. 79. DEVELOPING CAPACITY ALTERNATIVES  At the introduction phase, it can be difficult to determine both the size of the market and the organization’s eventual share of that market.  Therefore, organizations should be careful in making large and /or inflexible capacity investments  In the growth phase the overall market may experience rapid growth.
  80. 80. DEVELOPING CAPACITY ALTERNATIVES  In the maturity phase the size of market levels off, and organizations tend to have stable market shares  Organizations may still be able to increase profitability reducing costs and making full use capacity  However, some Organizations may still try to increase profitability by increasing capacity if the believe this stage will be fairly long, or the cost to increase capacity is relatively small.
  81. 81. DEVELOPING CAPACITY ALTERNATIVES  In the decline phase Organization is faced with underutilization of capacity due to declining demand  Organizations may eliminate the excess capacity by selling it or by introducing new products or services.  An option that is sometimes used in manufacturing is
  82. 82. DEVELOPING CAPACITY ALTERNATIVES  To transfer capacity to a location that has lower labour costs, which allows the Organization to continue to make a profit on the product for a while longer.  3 take a ‘’big-picture’’(i.e. systems) approach to capacity changes.  When Developing capacity alternatives , it is important to consider how parts of the system interrelate.
  83. 83. DEVELOPING CAPACITY ALTERNATIVES  For example ,when making a decision to increase the number of rooms in a motel, one should also take into account probable increased in demand for parking, entertainment, and food, housekeeping. This is a ‘’big-picture’’ approach  The risk in not taking a big-picture approach is that the system will be unbalanced.
  84. 84. DEVELOPING CAPACITY ALTERNATIVES  Evidence of unbalanced system is the existence of a bottleneck operation.  A bottleneck operation is an operation in a sequence of operations whose capacity lower than the capacities in other operations in the sequence  As a consequence, the capacity of the bottleneck operation limits the system capacity.  The capacity of the system is reduced to the capacity of the bottleneck operation .
  85. 85. DEVELOPING CAPACITY ALTERNATIVES  4. prepare to deal with capacity ‘’ chunks’’  Capacity increases are often acquired in fairly large chunks rather than smooth increments, making it difficult to achieve a match between desired capacity and feasible capacity  For instance, the desired capacity of a certain operation maybe 55 units per hour, but
  86. 86. DEVELOPING CAPACITY ALTERNATIVES  Suppose that machines used for his operation are able to produce 40 units per hour each  One machine by itself would cause capacity to be 15 units per hour short of what is needed  But two machines would result in an excess of capacity of 25 units per hour
  87. 87. DEVELOPING CAPACITY ALTERNATIVES  5 attempt to smooth out capacity requirements.  Unevenness in capacity requirements also create certain problems 6 Identify the optimal the operating level Production units typically have an ideal or optimal level operation in terms of unit cost of output. At the ideal ,cost per unit is the lowest for that production unit
  88. 88. EVALUATING ALTERNATIVES  Cost –volume analysis. manager has the option of purchasing one, two, or three machines. fixed cost and potential volumes are as follows  Num of total annual corresponding  Machines fixed costs range of o/t  1 $9600 0 to 300  2 15,000 301to 600
  89. 89. EVALUATING ALTERNATIVES  Variable cost is $10 per unit and revenue is $40 per unit  A)Determine the break even point for each range  B)if the projected annual demand is between 580 and 660 units, how many machines should the manager purchase
  90. 90. FACILITY LOCATION & LAYOUT  Layout refers to the configuration of departments, work centers ,and equipment , with particular emphasis on movement of work(customers or materials) though the system.  As in other areas of system design, layout decisions are important for three basic reasons
  91. 91. FACILITIES LAYOUT 1) They require substantial investments of money and effort 2) They involve long term commitments, which makes mistakes difficult to overcomes 3) They have a significant impact on the cost and efficiency of the operations
  92. 92. FACILITIES LAYOUT  The need for layout planning arises both in the process of designing new facilities and in redesigning existing facilities  The most common reasons for redesign of layouts include inefficient operations (e.g high cost, bottlenecks),accidents or safety hazards,  Changes in the design of products or services
  93. 93. FACILITIES LAYOUT  Introduction of products or services  Changes in the volume of output or mix  Changes in methods or equipments  Changes in environmental or other legal requirements and  Morale problems ( e.g lack of face to face contact)
  94. 94. FACILITIES LAYOUT  Poor layout design can adversely affect system performance.  The basic objective of layout design is to facilitate a smooth flow of work, material ,and information through the system .  Supporting objectives generally involve the following
  95. 95. FACILITIES LAYOUT  To facilitate attainment of products or services quality  To use workers and space efficiently  To avoid bottlenecks  To minimize material handing cost  To eliminate unnecessary movement of workers or materials  To minimize production time or customer service time  To design for safety
  96. 96. FACILITIES LAYOUT  The Three basic types of layout are  Product  Process and  Fixed-position  Product layouts are most conducive to repetitive processing  Process are used for intermittent Processing and Fixed-position are used when projects require layout.
  97. 97. REPETITIVE PROCESSING: PRODUCT LAYOUTS  is one in which equipment or work processes are arranged according to the progressive steps by which the product is made.  Product layouts are used to achieve a smooth and rapid flow of large volumes of goods or customers through a system.
  98. 98. REPETITIVE PROCESSING: PRODUCT LAYOUTS  This is made possible by highly standardized goods or services that allow highly standardized , repetitive processing.  The work is divided into a series of standardized tasks, Permitting specialization of equipment and division of labour.
  99. 99. REPETITIVE PROCESSING: PRODUCT LAYOUTS  In manufacturing environments, the lines are referred to as production lines or assembly lines  production lines : standardized layout arranged according to a fixed sequence of production tasks.+
  100. 100. REPETITIVE PROCESSING: PRODUCT LAYOUTS  Product layouts achieve a high degree of labour and equipment utilization , which tends to offset their high equipment costs .  Because items move quickly from operation to operation, the amount of work-in-process is often minimal  Consequently ,operations are so closely tied to each other that the entire system is highly vulnerable to being shut-down because of
  101. 101. REPETITIVE PROCESSING: PRODUCT LAYOUTS  Mechanical failure or high absenteeism  Eg. Automobile assembly  fast-food restaurants  The main advantage of Product layouts are 1. a high rate of output 2. Low unit cost due to high volume.the high cost of specialized equipment is spread over many units
  102. 102. REPETITIVE PROCESSING: PRODUCT LAYOUTS  Labour specialization, which reduces training costs and time ,and results in a wide span of supervision  Lower material –handling cost per unit  High utilization of labour and equipment
  103. 103. REPETITIVE PROCESSING: PRODUCT LAYOUTS  The primary disadvantages of product layouts include the following  Poor skilled workers may exhibit interset in maintaining equipment or in the quality output  The system is fairly inflexible in response to changes in the volume of the output or changes in product or process design
  104. 104. REPETITIVE PROCESSING: PRODUCT LAYOUTS  The system is highly susceptible to shutdown caused by equipment breakdowns or excessive absenteeism because work stations are highly interdependent
  105. 105. NON- REPETITIVE PROCESSING :PROCESS LAYOUTS  process layouts are designed to process items or provide services that involve a variety of processing requirements.  The variety of jobs that are processed requires frequent adjustments to equipment  This causes a discontinuous workflow, which is referred to as intermittent processing
  106. 106. NON- REPETITIVE PROCESSING :PROCESS LAYOUTS  The layouts feature departments or other functional groupings in which similar kinds of activities are performed  A manufacturing example of a process layout is the machine shop, which has separate departments for milling ,grinding ,drilling , and so on.
  107. 107. NON- REPETITIVE PROCESSING :PROCESS LAYOUTS  process layouts are quite common in service environment  Because equipment in a process layout is arranged by type rather than by processing sequence , the system is much less vulnerable to shut down caused by Mechanical failure or absenteeism
  108. 108. ADVANTAGES AND DISADVANTAGES  The Advantages of process layouts include the following  The system can handle a variety of processing requirements  The system are not particularly vulnerable to equipment failures  General-purpose equipment is often less costly than the specialized equipment used in product layout and is easier and less costly to maintain
  109. 109. DISADVANTAGES  In process inventory can be high if batch processing is used in manufacturing systems  Equipment utilization rates low  Material handling is slow
  110. 110. FIXED –POSITION LAYOUTS  In Fixed –position layouts, the item being worked remains stationary , and workers, materials, and equipments are moved as needed.
  111. 111. DESIGNING PRODUCT LAYOUTS: LINE BALANCING  The goal of a product layout is to arrange workers or machines in the sequence that operations need to be performed.  The sequence is referred to as a production line or as assembly line  These lines range from fairly short , with just a few operations, to long lines that have a large number of operations
  112. 112. LINE BALANCING  Line balancing  The process of assigning tasks to workstations in such a way that the workstations have approximately equal time requirements  The goal of Line balancing is to obtain task groupings that represent approximately equal time requirements. This minimizes the idle time along the line and result in high utilization
  113. 113. LINE BALANCING  Of labour and equipment.  Idle times occurs if task times are not equal among workstations; some stations are capable of producing at higher rates than others.  How does a manager decide how many stations to use?  The primary determinant is what the line’s cycle time will be?
  114. 114. LINE BALANCING  The cycle time is the maximum time allowed at each work station to perform assigned tasks before the work moves on.  The cycle time also establishes the output rate of a line  For instance, if The cycle time is two minutes , units will come off the end of the line at the rate of one every two minutes
  115. 115. LINE BALANCING  Suppose that the work required to fabricate a certain product can be divided up into five elemental tasks, with the task times and precedence relationships as following diagram  The task times govern the range of possible cycle times. 0.1 m 0.7m 1m 0.5m 0.2m
  116. 116. LINE BALANCING  The minimum cycle time is equal to the longest task time ( 1 minute) and  The maximum cycle time is equal to the sum of task times ( 0.1+0.7+1+0.5+0.2=2.5 minutes)  Output rat= operating time per day cycle time 
  117. 117. LINE BALANCING  Assume that the line will operate for eight hours per day( 480 minutes) .with a cycle time of 1 minute, output would be  480 minutes per day =480 units per day 1 minute per unit With a cycle time of 2.5 minutes, output would be  480 minutes per day =192 units per day 2.5 minutes per unit
  118. 118. LINE BALANCING  Assuming that no parallel activities are to be employed ( e.g.. two lines ), the output selected for the line must fall in the range of 192 units per day to 480 units per day  As a general rule , the cycle time determined by desired output, that is, a desired output is selected ,and the cycle time is computed.
  119. 119. LINE BALANCING  If the cycle time does not fall b/n maximum and minimum bounds, the desired output rate must be revised.  cycle time= operating time per day  desired output rate  E.g. , suppose that the desired output rate is 480 units  480 minutes per day= 1 minute per unit  480 units per day
  120. 120. LINE BALANCING  The number of workstations that will be needed is a function of both the desired output rate and our ability to combine elemental tasks into workstations  We can determine the theoretical minimum number of workstations necessary to provide a specified rate of output as follows:
  121. 121. LINE BALANCING  N min = t cycle time where N min= the theoretical minimum number of stations t =sum of task times
  122. 122. LINE BALANCING  Suppose the desired rate of output is the maximum of 480 units per day.( This will require a cycle time of 1 minute.)  The minimum number of stations required to achieve this goal is  N min= 2.5 minutes per day unit = 2.5 stations  1 minute per unit per station 
  123. 123. LINE BALANCING  Because 2.5 stations is not feasible, it is necessary to round up to three stations  A very useful tool in line balancing is a precedence diagram  A simple precedence diagram  0.1 min 1min    0.7min 0.5min 0.2 min a b c d e
  124. 124. LINE BALANCING  The general procedure in line balancing is described as follows  1 determine the cycle time and the minimum number of workstations  2 make assignments to workstations in order , beginning with station 1 .tasks are assigned to workstations moving from left to right through the precedence diagram
  125. 125. LINE BALANCING  3 )before each assignment, use the following criteria to determine which tasks are eligible to be assigned to a workstation:  A) all preceding tasks in the sequence have been assigned  B) the task time does not exceed the time remaining at the workstation.  If no tasks are eligible ,move on to the next workstation
  126. 126. LINE BALANCING  4) after each task assignment, determine the time remaining at current workstation by subtracting the sum of times tasks assigned to it from the cycle time  5) break ties that occur using one of these rules  A) assign the task with longest task time  B) assign tasks with the greatest number of followers
  127. 127. LINE BALANCING  6) continue until all tasks have been assigned to workstations  7) compute the appropriate measures( e.g. percent idle time, efficiency ) for the set of assignments.
  128. 128. LINE BALANCING  Two widely used measures of effectiveness are  1) percentage of idle time of the line.  This is sometimes referred to as the balance delay percentage of idle time=idle time per cycle x 100 N actual x cycle time where N actual= actual number of station
  129. 129. LINE BALANCING  percentage of idle time = 0.5 x 100 =16.7%  3x1  2) the efficiency of the line .this is computed as follows  Efficiency=100% - percent idle time  Efficiency=100% -16.7%=83.3%
  130. 130. LINE BALANCING  Using the following information contained in the table shown, do each of the following 1. Draw a precedence diagram . 2. Assuming an eight-hour workday, compute the cycle time needed to obtain an output of 400 units per day. 3. Determine the minimum number of workstations required
  131. 131. LINE BALANCING 4 assign tasks to workstations using this rule : assign tasks according to greatest number of following tasks. In case of a tie,use the tiebreaker of assigning the task with the longest processing time first.
  132. 132. LINE BALANCING task Immediate follower Task time (in minutes) A B 0.2 B E 0.2 C D 0.8 D F 0.6 E F 0.3 F G 1 g H 0.4 h End 0.3
  133. 133. LINE BALANCING  Compute the resulting percent idle time and efficiency the of system.