Planning for Production

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Chapter 3

• Planning for Production
• Going Green

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Chapter Highlights

• The factory system developed in the nineteenth
  century did not rely on skilled labor.
• The production line created by Henry Ford is one
  of the most effective manufacturing systems in
  use.
• Product-oriented manufacturing systems are
  replacing people-oriented systems.

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Chapter Highlights

• Production managers are changing manufacturing
  systems to manufacture smaller lot sizes with
  less lead time.
• Push, pull, and kanban are names associated with
  responsive manufacturing systems.
• Lean manufacturing can become the pathway to
  green manufacturing.

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Introduction

• The basis for a manufacturing system
• More than 200 years ago, Adam Smith wrote about
  improving manufacturing output through the
  division of labor.
• In 1798 Eli Whitney demonstrated the value of
  interchangeable parts.
• In early factories
• Skilled workers were essential.
• Quality was based on craftsmanship learned
  through experience/apprenticeship.

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Unskilled Factory System

• In the nineteenth century, the skilled factory
  system could not keep up with the demand of the
  United States.
• Frederick Taylor introduced scientific management
  as the basis for creating the unskilled factory.
• Divided skilled jobs into simple tasks
• Defined exactly how to do ataskmotion study
• Determined how long it takes to do a tasktime
  study

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The Production Line Factory System

• The unskilled factory was seldom well organized
  and generally chaotic
• Henry Ford created the production line
• The production line provided key three benefits
• Does not require a worker to move the product to
  the next workstationestablished product flow
• Establishes a specific route and location for
  workstations
• Created a pace for work to be accomplished

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The Production Line Factory System

• However, the real benefit was the third
  pointwhich established a manufacturing rate or
  cycle time to complete a task.

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Product-Oriented vs.People-Oriented Factory
System

• Manufacturing management in most factories seemed
  to focus only on the labor cost in the product.
• The objective was to minimize the time it took to
  complete the task and reduce the cycle time for
  the task.
• Keeping workers busy was a goal of management.

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Product-Oriented vs.People-Oriented Factory
System

• The result was a buildup of materials called work
  in progress (WIP) on the factory floor.
• Management used incentive systems, which
  significantly increased excess WIP (work in
  progress).

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People-Oriented Manufacturing Systems

• It is important to recognize why excess WIP is a
  problem. Here is an example. Below is a list of
  operations to make a simple product. All cycle
  times are equal.
• This is an ideal situation since it should cause
  hardly any WIP to develop between workstations.

Task ID Task Standard Cycle Time
1. Stamp out the part in a press. 10 seconds (.00278 hours)
2. Spot-weld a tab on the part. 10 seconds (.00278 hours)
3. Spray paint the assembly. 10 seconds (.00278 hours)
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People-Oriented Manufacturing Systems

• However, assume a work methods analyst made a
  change in Task 2, reducing cycle time to 8
  seconds. Will this cause a labor savings or just
  cause an increase in WIP?

Task ID Task Standard Cycle Time
1. Stamp out the part in a press. 10 seconds (.00278 hours)
2. Spot-weld a tab on the part. 8 seconds (.00222 hours)
3. Spray paint the assembly. 10 seconds (.00278 hours)
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People-Oriented Manufacturing Systems

• What can be done with the extra time available
  due to the faster cycle time?
• Keeping the worker busy also means keeping
  machines busy. Either way it has the same result
  excess WIP.
• Manufacturing management during the last half of
  the twentieth century was also focused on machine
  utilization and efficiency.

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People-Oriented Manufacturing Systems

• Goldratt and Cox, in their novel The Goal,
  describe the problems that occur when
  manufacturers define the effectiveness of a
  manufacturing system in terms of machine/worker
  utilization or efficiency.

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Product Flow Manufacturing Systems

• Fords first production line dealt with a single
  product. There were no optional colors or
  packages.
• Today automotive production lines have to
  accommodate a wide variety of options and
  different models of automobiles.
• However, the manufacturing system developed by
  Henry Fords engineers and technicians had one
  very significant attribute it was product flow
  oriented.

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Product Flow Manufacturing Systems (Cont.)

• A product flow system is committed to keeping
  products movingbeing completed and shipped.
• A symptom of a manufacturing system that is not
  moving product is excess WIP. Parts, assemblies,
  and partially completed products are examples of
  WIP.
• Ideally the only WIP should be in a workstation
  being worked on or arriving just in time (JIT) to
  be worked on.

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Product Flow Manufacturing Systems (Cont.)

• The term just in time has become synonymous with
  product flow manufacturing systems.
• In the 1980s, manufacturing management became
  very enthusiastic about JIT, but generally saw it
  as only an inventory-reduction concept.
• Those companies that tried to implement JIT found
  that they could no longer operate machines and
  workstations as decoupled activities.

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Product Flow Manufacturing Systems (Cont.)

• Once the operations and processes are tied
  together, workers or machines might be idled
  waiting for product to flow into the workstation.

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Product Flow Manufacturing with JIT

• Any obstructions to product flow caused a
  bottleneck or stopped production, since there is
  no excess WIP to keep downstream workstations
  busy.
• This interruption immediately focuses everyones
  attention on the machine or workstation causing
  the obstruction.
• The negative aspect occurs when the organization
  cannot resolve the problem or prevent it from
  recurring.

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Product Flow Manufacturingwith JIT (Cont.)

• If the problem goes unresolved, excess WIP will
  creep back into the manufacturing system,
  destroying product flow.
• JIT creates painthat is good. It draws attention
  to product flow problems wherever they occur.

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Product Flow Manufacturing Systems

• Product flow has developed into a system called
  lean manufacturing
• There are five fundamental facets of
  manufacturing that are common to product flow and
  lean manufacturing systems
• Quality
• Reliability
• Setup time
• Operator ability
• Material availability

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Basis for Lean and Green ManufacturingQuality

• Quality programs in lean manufacturing are based
  on a systematic approach to eliminate and prevent
  waste (non-value-added activities) in the
  production of a product
• Prime examples of non-value-added activities are
  delays and repair/rework due to defective
  materials or manufacturing
• Some managers are surprised when they learn that
  inspection of parts and products is a
  non-value-added activity

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Basis for Lean and Green ManufacturingQuality

• What is manufacturings responsibility for
  quality?
• It has to create a production system that can
  replicate the product design.
• A lean manufacturing system replicates the design
  with minimal waste.
• Engineers/designers have a major role in ensuring
  that a product can be successfully manufactured.
  This activity is called designing for manufacture.

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Basis for Lean and Green ManufacturingQuality

• The equipment and processes selected to make the
  product must be robust and appropriate for
  manufacturing the product.
• Manufacturing system robustness means that the
  system can tolerate the natural variability of
  the manufacturing environment.

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Basis for Lean and Green ManufacturingQuality

• The following three characteristics are usually
  found in a green manufacturing operation
• An environmental management system
• An organized approach for pollution prevention
• A lean manufacturing operation that includes Six
  Sigma

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Basis for Lean and Green ManufacturingWaste
Reduction

• P2 (Pollution Prevention) programs emphasize
  reducing or eliminating waste at its source by
• Modifying production processes
• Using nontoxic or less toxic materials and
  supplies
• Minimizing the use of resources
• Recycling to minimize waste streams

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Basis for Lean and Green ManufacturingStatistical
Process Control

• A key element in being able to consistently
  replicate design characteristics is the
  application of Statistical Process Control (SPC).
  
• This technique provides manufacturers with a
  simple but effective way to confirm that a
  manufacturing operation or process is under
  control.
• When used properly, SPC can detect the onset of a
  major problem even before bad parts are made.

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Basis for Lean and Green ManufacturingStatistica
l Process Control
There are three basic steps to institute SPC

• Establish control. Bring the process or activity
  into control. Make it capable of replicating
  consistently, thus making the process or
  operation predictable.
• Monitor the activity. Establish a means to
• Visually portray and track the performance of the
  activity.
• Learn how to recognize when the activity is not
  performing normally.

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Basis for Lean and Green ManufacturingStatistica
l Process Control
There are three basic steps to institute SPC

1. Problem solve. Train the manufacturing personnel
   to be effective problem solvers so they can bring
   the activity back into control.

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Basis for Lean ManufacturingReliability

• Delays and interruptions due to machines and
  tools breaking are common reasons for
  lower-than-expected production output.
• Manufacturing organizations long ago established
  maintenance departments to respond to these
  unplanned interruptions of work.

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Basis for Lean ManufacturingReliability

• This approach is called breakdown or reactive
  maintenance. This is a cost-adding solution. To
  overcome these interruptions
• Production departments create safety stocks
  (excess WIP) of production materials to keep
  running or to keep people busy.
• Production departments use overtime to catch up
  once the repaired machine is back in production.

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Basis for Lean ManufacturingReliability

• In 1950, Japanese engineers started what should
  have been an obvious concept. They instituted a
  maintenance program based on following the
  machine manufacturers recommendations.
• That approach was called preventive maintenance.

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Basis for Lean ManufacturingReliability

• The approach had an unusual featureit required
  operators to take an active role in maintaining
  their equipment (oil, clean, etc.).
• The maintenance department and the people
  operating the equipment worked in partnership to
  prevent equipment breakdowns.

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Basis for Lean ManufacturingReliability

• In the 1960s and 1970s, a more effective approach
  was developed called productive maintenance.
• This method involved the maintenance department
  and the machine operators, but it brought in
  another group manufacturing engineers and
  technicians.

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Basis for Lean ManufacturingReliability

• These engineers/technicians quantified the
  reliability of the equipment and determined their
  mode of failure. Productive maintenance focused
  on improving equipment reliability.
• The preventive maintenance schedule was changed
  to respond to the probability of failure under
  actual production stress. This approach also
  eliminated many unnecessary preventive
  maintenance activities.

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Basis for Lean ManufacturingReliability

• Total productive maintenance or total
  participation maintenance is based on preventive
  maintenance techniques and diagnostic analysis of
  the equipment.
• Cleaning equipment is an effective diagnostic
  activity. This builds on the operators role and
  frequently detects symptoms of problems that
  could cause a breakdown.
• As an example oil leaks, loose bolts, partially
  clogged filters are examples of what can be found
  while cleaning.

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Basis for Lean ManufacturingReliability

• Involving people not familiar with the equipment
  and its operation can help too. Examples are
• Material suppliers can provide useful suggestions
  when they see how their product is used in the
  manufacturing process.
• Suppliers of generic replacement parts should be
  asked to look at worn or failed parts and make
  suggestions for improvement.

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Basis for Lean ManufacturingSetup Reduction

• Downtime caused by setup or changeovers is the
  same as a machinery breakdown in a product flow
  system.
• Setup reduction, the third facet of lean
  manufacturing.
• In the past, managers have grouped like parts
  together to increase the length of a production
  run.

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Basis for Lean ManufacturingSetup Reduction

• This does not reduce the time it takes to do a
  setup it merely reduces the frequency of setups.
  
• Unfortunately, this approach also results in
  bigger lot sizes, more WIP, and often extends the
  lead time for a customers order.

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Basis for Lean ManufacturingSetup Reduction

• Successful companies have organized themselves
  specifically to reduce setup time.
• They approach setup reduction the same way a
  NASCAR team views a pit stop. Its a team task,
  special tools are needed, and each person
  involved has specific responsibilities.
• Reducing setup times aims at improving product
  flow. It also has a major effect in making the
  manufacturing process more responsive.

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Basis for Lean ManufacturingSetup Reduction

• In the 1980s and 1990s, managers talked about
  manufacturing systems handling a lot size of one.
  
• Setups and changeovers were done so quickly that
  they did not impede the flow of product.

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Basis for Lean ManufacturingSetup Reduction
Procedure

• Here is one procedure that has been used to
  reduce/eliminate setups
• Form a setup team, which will include the machine
  operators, setup people, and plant/production
  engineers.

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Basis for Lean ManufacturingSetup Reduction
Procedure

• Establish baselines.
• Determine how long it now takes to do a setup.
• Calculate the target manufacturing lot size.
  This is based on customer order quantities.
• Calculate the number of setups needed per shift
  to meet the target manufacturing lot size.
• Determine the target setup time.
• Divide the free machine time during a shift by
  the number of setups per shift to get the target
  setup time.

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Basis for Lean ManufacturingSetup Reduction
Procedure

• Video record the current setup process so it can
  be analyzed.
• Separate external from internal tasks
• External tasks are setup tasks that can be
  accomplished while the machine is still operating
  and do not add to the downtime.
• Internal tasks require shutting down the machine.
  
• Take advantage of this difference and focus on
  reducing or eliminating the tasks that keep the
  machine from producing product.

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Basis for Lean ManufacturingSetup Reduction
Procedure

• The setup reduction team needs managements
  support and insistence to develop an innovative
  solution to achieve the target setup time.

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Basis for Lean ManufacturingOperator Ability

• This facet has been called operator self-control
  or Jidoka, which in Japanese is loosely
  interpreted as autonomous defect control.
• Ensuring that each person is able to fulfill this
  responsibility is an essential building block in
  creating a lean manufacturing environment.
• Each individual is a manager and must be able to
  effectively manage his or her own work.

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Basis for Lean ManufacturingOperator Ability

• Therefore, to manage the assigned work, each
  person must possess the knowledge and skill to
• Do the task correctly.
• Recognize that the materials being used meet the
  required standards.
• Determine that the tools, equipment, etc. to do
  the work are in proper working order.

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Basis for Lean ManufacturingOperator Ability

• Therefore, to manage the assigned work, each
  person must possess the knowledge and skill to
• Recognize if the task is not being done as it
  should be and be willing to take corrective
  action.
• Obtain help to solve the problem when the problem
  cannot be corrected with the resources at hand.
• Never let a problem/defect move on in the
  manufacturing process.

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Manufacturing SystemPush SystemsPull Systems

• The terms push and pull describe how a product
  moves through a factory.
• When an order is received, a push system(MRP
  system) begins by ordering materials, then
  establishing a start date to begin production
  based on when the materials will be available.
• Once materials are available, the push system
  schedules the order through the plant from the
  starting operation to the final shipping point.

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Manufacturing SystemPush SystemsPull Systems

• Push systems push the product through the
  factory.
• Pull systems try to respond immediately by
  shipping the order when it is received.
• Shipping the order then creates a demand that
  moves back up the production line to replace what
  has just been shipped.

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Manufacturing SystemPush SystemsPull Systems

• For a pull system to be responsive,
  work-in-process must be available at every
  operation involved in the production of the
  product.
• In practice, a pull system has proven to be very
  responsive and effective in synchronizing
  production activity with demand.

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Pull System
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Kanban Approach

• The Kanban signal to initiate production consists
  of a card and a container (tote pan or storage
  space). Heres how it works
• When a using department withdraws a container of
  parts, the card previously attached to it by the
  producing (upstream) department is detached and
  placed in a collection box.

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Kanban Approach

• When the most recently emptied container for the
  same parts is returned to its producing
  department, the card from the collection box is
  attached to it
• When the producing department receives this empty
  container, the card is removed and placed into a
  recently manufactured container, full of parts,
  that is then sent to the using department
• This process repeats itself over and over again

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Summing Up

• Lean and green manufacturing is a strategy to
  enable manufacturers to produce products with a
  minimum of waste
• The goal of lean manufacturing is to effectively
  produce what the customer requires with a minimum
  of waste or delay

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Summing Up

• A key characteristic of a lean manufacturing
  facility is robustness, meaning that it is able
  to function effectively even under the changing
  circumstances that occur in the day-to-day
  operation of the factory
• Reliability and quality are also traits of a lean
  manufacturing facility. Reliability includes
  people that can be depended on to do what needs
  to be done as well as suppliers that deliver the
  right materials on time all the time.

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Summing Up

• Implementing programs that will ensure that
  equipment does not break down unexpectedly, as
  well as developing and maintaining a quality
  process to prevent defects, are important parts
  of a successful lean manufacturing strategy

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Summing Up

• The concept of JIT (just-in-time) has become
  associated with lean manufacturing because it
  minimizes or eliminates excess work in process,
  which will result in a reduction of inventoryan
  important objective

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Summing Up

• However, JIT has a more significant role to
  perform for lean manufacturers. JIT ensures that
  any problem impacting product flow will
  immediately become apparent by causing an
  interruption in production.

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Summing Up

• This interruption occurs because JIT eliminates
  the extra stock to replace defective parts,
  prevents stocking surplus inventory to cover a
  suppliers missed shipment, or maintaining an
  emergency stock to bridge the time it takes to
  fix a broken down machine