IE 3265 -- POM

1
IE 3265 -- POM

• Comparing the JOB SHOP to the FLOW SHOP
• -- a consideration of opposites

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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

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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!

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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
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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

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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

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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.

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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!

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FOCUSING on the Job Shop
This confusion leads to lost time and lost
production!
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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!

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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

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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

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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

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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

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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

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FOCUSING on the Job Shop

• The Greatest Negative is a Lack of Overall
  Control
• Parts dont get out on time
• Quality is variable
• Schedules slip
• Material Handling is a Nightmare

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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.

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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 1940s, 50s
  and 60s. 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.

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FOCUSING on the Flow Shop
Orderly and efficient flows of specific products
characterize the Flow Shop
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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

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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

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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

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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 products 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

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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

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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

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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

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Summarizing these Comparisons -- Focus on The
Specifics

• People
• Processes
• System Control
• Material Handling

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Focus on People

• Job Shop
• Skilled Specialists within a Process department
• Quality depends on Individual Skills
• Skills are disbursed throughout staff --
  operations are defined by individuals 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

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Focus on Processes

• 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

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Focus on System Control

• 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

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Focus on Material Handling

• 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
  

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Summary

• During this lesson, we focused on the Job Shop
  and the Flow Shop Manufacturing Systems. We
  learned about both their positive and negative
  aspects concerning People, Processes, Control and
  Material Handling. We found that while each has
  a niche in modern manufacturing, both could be
  improved by borrowing aspects from the other.
  In the next lesson we will explore Cellular
  Manufacturing Systems a manufacturing philosophy
  that borrows from both and enables Mass
  Customization to become a reality