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Planning for Production

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Title: Planning for Production


1
(No Transcript)
2
Chapter 3
  • Planning for Production
  • Going Green

3
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.

4
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.

5
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.

6
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

7
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

8
The Production Line Factory System
  • However, the real benefit was the third
    pointwhich established a manufacturing rate or
    cycle time to complete a task.

9
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.

10
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).

11
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)
12
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)
13
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.

14
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.

15
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.

16
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.

17
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.

18
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.

19
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.

20
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.

21
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

22
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

23
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.

24
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.

25
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

26
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

27
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.

28
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.

29
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.

30
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.

31
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.

32
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.

33
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.

34
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.

35
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.

36
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.

37
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.

38
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.

39
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.

40
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.

41
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.

42
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.

43
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.

44
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.

45
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.

46
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.

47
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.

48
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.

49
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.

50
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.

51
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.

52
Pull System
53
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.

54
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

55
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

56
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.

57
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

58
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

59
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.

60
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
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