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IE 3265 -- POM

IE 3265 -- POM. Comparing the JOB SHOP to the FLOW SHOP -- a consideration of opposites. Layout and Flow Considerations. GENERALLY SPEAKING, INTERNAL MATERIAL HANDLING ACTIVITIES MUST BE MINIMIZED!! When a plant is designed, minimize the length of product flow paths

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IE 3265 -- POM

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  1. IE 3265 -- POM Comparing the JOB SHOP to the FLOW SHOP -- a consideration of opposites

  2. Layout and Flow Considerations • GENERALLY SPEAKING, INTERNAL MATERIAL HANDLING ACTIVITIES MUST BE MINIMIZED!! • When a plant is designed, minimize the length of product flow paths • When a process is designed, minimize the number of times a product must be handled (picked or placed) • When designing a plant or process minimize the cost and difficulty of between step transfers • When building the facility confine flow to a single level, if possible • When designing product flow place operations uni-directionally with minimal backtracking IE 3265, Job VS Flow Shops

  3. Layout and Flow Considerations • Generally Speaking Avoid Clutter and Minimize Work In Process (WIP) • Consider Bottleneck Processes --Replicate the resource or Plan Special Flow Paths around their areas • Design Special Handling Practices that minimize time and product damage • Consider small batches or One-at-a-time moves • If possible design Drying/Curing Systems into the Transport System • Handle Products only as needed -- loading/unloading/reloading of totes, pallets or tubs is wasteful and should be avoided during design! IE 3265, Job VS Flow Shops

  4. Layout and Flow Considerations Summarizing these ideas then, Layout and Flow must be integrated into the overall design or redesign of a manufacturing facility An effective Facility Designer must consider material flow throughout the design phase. This consideration must begin at the workstation, move up to the department or area and finally be carried into a PLAN for the entire facility IE 3265, Job VS Flow Shops

  5. Processing in Job Shops or Flow Shops • Generally Speaking, The Job Shop uses a FUNCTIONAL LAYOUT • In the functional layout, like processors are grouped into departments. As products visit the department they are placed on one of the processors of the group. • Generally Speaking, The Flow Shop uses a PRODUCT LAYOUT • In the product layout the required processors for a product are identified and arranged using a linked station-to-station alignment IE 3265, Job VS Flow Shops

  6. Comparing the Details of the “Competing” Systems Over the series of slides that follow, we shall explore the various attributes of these alternative Manufacturing Systems as they strive to provide an Efficient Manufacturing Environment

  7. FOCUSING on the Job Shop • Historically, the functional layout is the logical outgrowth of the “Garage Business” basis of Manufacturing. As the work load increases, the original owner/operator (equipped with a small number of general purpose machines) will hire a second generalist. Then, as the the word gets out that the firm has certain skills, the growth pattern tends to favor expansion of one or another of the processes, typically in “fits and starts.” Then, with this haphazard growth pattern and the redirection of the original owner, the need for technical experts and process centered areas make sense. As the business grows the functional areas or departments are a natural evolutionary pattern, cont. IE 3265, Job VS Flow Shops

  8. FOCUSING on the Job Shop • And so the facilities grows --- New People, Expanded Departments, Expanded Buildings and on and on. Thus, as new products enter this expanded shop environment, their flows must be reasoned out because no one person has control of all the processes. Here we perform a process planning activity and develop a routing sheet. Then as the product orders are released for production the batch starts moving through the shop along its tortuous path. Moving department to department as listed on the Routing Sheet, often with many idle hours or days waiting to get on the processor. After it completes its processing in a department, it waits for pickup before being moved into a waiting station at the next department, and so on an so on. In this expanded shop then, the idle days for any given product tend to grow as the number of active orders grow! IE 3265, Job VS Flow Shops

  9. FOCUSING on the Job Shop This confusion leads to lost time and lost production! IE 3265, Job VS Flow Shops

  10. FOCUSING on the Job Shop • In the modern manufacturing environment the Job Shop displays many desirable qualities: • Flexibility – many different products if they are “within a type” • Well versed, trained workers who understand processing techniques help to control operations and product quality as production proceeds • Product lot size can be small – can easily make batches of 1 to 50 pieces reliably and repeatability -- BUT most seldom do! IE 3265, Job VS Flow Shops

  11. FOCUSING on the Job Shop • In the modern manufacturing environment the Job Shop displays many desirable qualities (cont.): • Most machines can make any required operational step (within the function) – concern would be with individual operator and/or individual machine capability • Flexible material handing tracks can be easily developed as new products are introduced to the system • Storage of product where it is needed and delivery of raw material “to the point of work” is the norm IE 3265, Job VS Flow Shops

  12. FOCUSING on the Job Shop • And the GREATEST of these is FLEXIBILITY!! • Flexibility means that we can make just what the customer wants when they want it • Flexibility means that we can quickly get new products into production and “out the door” IE 3265, Job VS Flow Shops

  13. FOCUSING on the Job Shop • And the GREATEST of These is FLEXIBILITY, cont. • Flexibility means that we can avoid the problems of bottlenecks and breakdowns since each department has sets of “parallel resources” IE 3265, Job VS Flow Shops

  14. FOCUSING on the Job Shop • Negative Attributes of the Job Shop • Setups, while simple, require the dedicated attention of a skilled worker and can be time consuming • Skilled workers are expensive, due to increasingly short supply, and (many times) are not flexible – they are specialized to PROCESS type • Complex material handling patterns and on the floor storage lead to long and unpredictable lead times, difficult scheduling and potentially, product quality control concerns IE 3265, Job VS Flow Shops

  15. FOCUSING on the Job Shop • Negative Attributes of the Job Shop, cont. • Once a batch of parts enters production if an error is made in any processing step it is often many days later before it is found and the entire batches many need to be scraped because of simple oversights • Material Handling Systems that are not optimized to products or flow paths • Bins, totes etc are rarely packed optimally • Forklift Trucks are either underutilized or overutilized “Why do we have so many Forktrucks” OR “We never have a Forktruck when we need one” are common problems • Lot identity is often obscured or lost completely • Tracking orders is a Full Time Job for Supervisors or expeditors IE 3265, Job VS Flow Shops

  16. FOCUSING on the Job Shop • The Greatest Negative is a Lack of Overall Control • Parts don’t get out on time • Quality is variable • Schedules slip • Material Handling is a “Nightmare” IE 3265, Job VS Flow Shops

  17. FOCUSING on the Flow Shop • Historically, the Flow Shop style of manufacturing evolved from the demands placed on manufacturers to produce large numbers of similar or identical parts beginning with the Assembly Lines of Ford Motor Company. These ideas were fine tuned during WW II as large amounts of material and equipment (all identical) were being produced and shipped to fight the war across the globe. Here, cost and time usage had to be minimized with high and repeatable quality built into all products, cont. IE 3265, Job VS Flow Shops

  18. FOCUSING on the Flow Shop • Using a systematic make - one - pass - one idea with “all products the same” made the most practical sense during these times. After all, OD was the color of choice when the fighting was on. These ideas survived the war, and served the U.S. Manufacturer well through the 1940’s, 50’s and 60’s. However, with changing tastes and the advent of the “Mass Customization” of the present age, some of the ideas like “all products the same” of the flow shop will need to evolve. IE 3265, Job VS Flow Shops

  19. FOCUSING on the Flow Shop Orderly and efficient flows of specific products characterize the Flow Shop IE 3265, Job VS Flow Shops

  20. FOCUSING on the Flow Shop • In the modern manufacturing environment the Flow Shop displays many desirable qualities: • Production times and costs are well understood and predictable • Large lots can be efficiently processed and delivered on time • Skilled labor is not required to produce high quality products – quality is designed into the processing operations themselves • Flow Line can tolerate minor product variations with little difficulty IE 3265, Job VS Flow Shops

  21. FOCUSING on the Flow Shop • In the modern manufacturing environment the Flow Shop displays many desirable qualities, cont.: • WIP is controlled, it is minimized to just keep the product flow steady • Warehousing spaces and configuration are optimized and maintain a controlled inventory of finished product • Material Handling systems are specially built and optimized to minimize handling costs per unit IE 3265, Job VS Flow Shops

  22. FOCUSING on the Flow Shop • And the GREATEST of these is Predictability!! • Predictability means that we can deliver products in a timely fashion • Predictability means that production cost and profitably are constant and reliable business data IE 3265, Job VS Flow Shops

  23. FOCUSING on the Flow Shop • Negative Attributes of the Flow Shop • Line Setups are lengthy and costly thus the number should be minimized to reduce overhead costs • Specialty Equipment, machines and tooling (for production or material handling) is costly to design or purchase and may be difficult to reconvert at the end of a product’s life cycle • Production and Material Flow knowledge is concentrated in a few key workers – the system is dependent on these few for getting the work done IE 3265, Job VS Flow Shops

  24. FOCUSING on the Flow Shop • Negative Attributes of the Flow Shop, cont • Many times a simple breakdown at any stage will stop all production -- clogging queues with WIP – designers must design redundancy into the line to avoid costly stoppages increasing overall system cost • Product Quality of large numbers of product can suffer if any processor moves out of “calibration” • Many times duplicates of the most costly of equipment are needed on parallel production lines because the resource must be dedicated to a single product rather than shared in a logical way IE 3265, Job VS Flow Shops

  25. FOCUSING on the Flow Shop • Negative Attributes of the Flow Shop, cont. • Large orders and extended production runs must be used to offset the initial costs of the production line and setup costs, even if demand is falling as a product life cycle is nearing the end. This can lead to over-production and fire sales of product during recessions and at the end of life for products -- consider for example Computer Microprocessors • Introducing a new product into an obsolete flow line usually very costly as well IE 3265, Job VS Flow Shops

  26. FOCUSING on the Flow Shop • The Greatest Negative Aspect is Inflexibility • Change to new products take time and large $ investments • Long runs and large quantities of essentially the same parts are required to justify the setup of the line IE 3265, Job VS Flow Shops

  27. Summarizing these Comparisons -- Focus on The Specifics: • People • Processes • System Control • Material Handling IE 3265, Job VS Flow Shops

  28. Job Shop Skilled Specialists within a Process department Quality depends on Individual Skills Skills are disbursed throughout staff -- operations are defined by individual’s skills Flow Shop Line is staffed by Semiskilled Machine Operators Quality is Built in by System Specialists and Set up Crew Knowledge is concentrated in Specialists Focus on People IE 3265, Job VS Flow Shops

  29. Job Shop Each “Department” is Process specific with several General Purpose Machines to chose from Not all Machines are Equal! Process Capabilities of each must be determined Sharing of Specialized Equipment is Possible with good scheduling and control Flow Shop Each Line is Specialized to a Product All Required Processors are linked on the line to complete a product in minimal time Many expensive and, potentially, sharable resources must be duplicated along each line to assure smooth flow Focus on Processes IE 3265, Job VS Flow Shops

  30. Job Shop Elaborate and Detailed Routing Sheets must be developed for each new Product Scheduling of Processes requires study and constant attention but output is still haphazard and unpredictable Products are Batched and carried through in groups to minimize setup costs for individuals items Flow Shops Lines are laid out to reflect product routing Simple schedules are required -- only monthly or weekly output goals, however, in the event of a Breakdown, line repair must be rapid to avoid slipping product deadlines Parts are sent down the lines as individuals, Time to produce one is predictable and controlled Focus on System Control IE 3265, Job VS Flow Shops

  31. Job Shop General Purpose units that can follow Variable Paths must be chosen Part Containers and Storage areas are rarely optimal for any given product Scheduling of Material Handling Resources requires the use of dedicated specialists Flow Shop Specially designed material handling devices and optimal handling methods are employed Raw and finished goods storage areas are optimally designed Material Handling Resources are considered during Line Design thus are integral to the system itself -- and they require no special scheduling Focus on Material Handling IE 3265, Job VS Flow Shops

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