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LEAN system


LEAN system LEAN referred as JIT (because the activities and delivery of goods occur just as they are needed) Begun in the mid 1900 s, developed by Toyota its goal ... – PowerPoint PPT presentation

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Title: LEAN system

LEAN system
  • LEAN referred as JIT (because the activities and
    delivery of goods occur just as they are needed)
  • Begun in the mid 1900s, developed by Toyota its
    goal is to eliminate every waste from every
    aspects of the process
  • Waste didnt add value to the process

Value ws.waste
  • "value" is defined as any action or process that
    a customer would be willing to pay for
  • Waste
  • muda ("non-value-adding work"),
  • muri ("overburden"), and
  • mura ("unevenness"),

The toyota approach
  • Muda waste and inefficiency must be minimized by
    using the following technics
  • Kanban a manual system responds to signals of
    the need for delivery of parts and materials
    (both to the factory and between the workstation)
  • Pull system produce only what is needed
  • Heijunka work load must be leveled to achive
    stedy flow of work

Not leveled workload
Leveled workload
  • Kaizen continuous improvement of the system
  • Jidoka each worker is expected to perform
    ongoing quality assurance, objective is to avoid
    passing defective products to the following work
  • Poka-Yoke safeguards built into the process to
    reduce the possibility of errors

JIT vs Ford system
  • the JIT system rooted in the system of Henry
  • But it can accomplish that Ford coludnt the
    system that colud handle with variety (product
    variety and range of volume)

(No Transcript)
Supporting goals
  • A balanced system, smooth, rapid flow of
    materials and/or work
  • To make a process time as short as possible
  • Supporting goals
  • Eliminate disruption
  • Make the system flexible
  • eliminate waste, especially exess inventory

1. Disruption
  • It upsets the smooth flow of the system
  • It is caused by
  • poor quality,
  • equipment breakdowns,
  • late deliveries

2. Flexible system
  • A system which is robust enough to handle a mix
    of products and changes in the level of output
  • Short setup time (Period required to prepare a
    device, machine, process, or system for it to be
    ready to function or accept a job.)
  • Short lead time (is the period of time between
    the initiation of any process of production and
    the completion of that process.)
  • Lead time for ordering a new car from a
    manufacturer may be anywhere from 2 weeks to 6

3. waste
  • The key step in LEAN is the identification of
    which steps add value and which do not
  • A process adds value by producing goods or
    providing a service that a customer will pay for.
  • value-adding work has been separated from waste
    then waste can be subdivided into 'needs to be
    done but non-value adding' waste and pure waste.

There are 7 wastes in LEAN (TIMWOOD)
  • Inventory - represents a capital outlay that has
    not yet produced an income either by the producer
    or for the consumer. It takes up floor space and
    adds to cost. ? inventory must be minimized
  • Overproduction engage more resources than
    needed to deliver to the customers. It is because
    batch production. Because of productivity
    improvement, operators are required to produce
    more than customer needs. It generates all other
    wastes, especially inventory.
  • Waiting - Whenever goods are not in transport or
    being processed, they are waiting. (becouse of
    not leveled workload.

  • Unnecessary transportation - Each time a product
    is moved it stands the risk of being damaged,
    lost, delayed, etc. as well as being a cost for
    no added value. Transportation does not make any
    transformation to the product that the consumer
    is supposed to pay for.
  • Processing waste unecessary steps of
    production, moves of workers, searching
    activities for tools,
  • Defects - Whenever defects occur, extra costs are
    incurred reworking the part, rescheduling
  • Inefficient work methods decrease productivity,
    for example inefficient replacement of
    inventorys, continuous quality check

  • The wastes are potential tartgets for continuous
    improvement, called kaizen.

JIT Building Blocks
  • Product design
  • Process design
  • Personnel/organizationalelements
  • Manufacturing planning and control

Product Design
  • Standard parts fewer parts to deal with ?lower
    training costs
  • ?use standard processing
  • Modular design clusters of partsn treated as a
    single unit. ? easy to satisfy different needs
  • Highly capable production systems quality is
    designed into the product and the production
  • Concurrentengineering

Process Design
  • Small lot sizes
  • Setup time reduction
  • Manufacturing cells
  • Limited work in process
  • Quality improvement
  • Production flexibility
  • Little inventory storage

Benefits of Small Lot Sizes
Production Flexibility
  • Reduce downtime by reducing changeover time -
    small lots require frequent setups.
  • SMED (single minute exchange of die)
  • External
  • Internal activities.
  • Use preventive maintenance to reduce breakdowns

Manufacturing cells
  • In Functional Manufacturing similar machines are
    placed close together (e.g. lathes, millers,
    drills etc)
  • In Cellular Manufacturing systems machines are
    grouped together according to the families of
    parts produced.
  • The major advantage is that material flow is
    significantly improved, which reduces the
    distance travelled by materials, inventory and
    cumulative lead times.

Quality improvement
  • Autonomation automatic detection of defects
    during production. It referres to jidoka
  • It consist two activities
  • One for detecting defects when they occure
  • Another for stopping production to correct the
    cuase of defects.

Work flexibility
  • Overall goal of lean is to achieve the ability to
    process mix of products in a smooth flow.
  • One potential obstacel is botlenecks, which
    occure when portions of the system become

Balanced system
  • Distributing te workload evenly among
  • Takt time is the cycle time needed in the
    production system to match th pace of production
    to the demand rate
  • Example
  • Total time per shift is 480 minutes per day
  • There are two shifts per day
  • There are two 20-minutes break and a 30 minutes
    lunch break per shift.
  • Daily demand is 80 pieces
  • Net time available per day 2(480-202-30)820min
  • Takt time820minutes/80 pieces10,25 minutes
  • If the actual ciycle time is higher, our
    customers wont get their needs, if the actual
    cycle time is lower, there will be
    overproduction, and we have to inventory surplus

Inventory sorage
  • Inventory storage in the lean philosophy is a
    waste, a buffer which can cover up problems,
    partly beause iventory makes them seem less
  • When a machine breaks down it wont disrupt the
    system if there is a sufficient inventory of the
    machines output.
  • Lean approach is to eliminate inventories in
    order to uncover the problems and solved. Then
    the systme removes more inventory, finds and
    solves additional problems.
  • One way of minimizing inventory is to have
    delivers from suppliers go directly to the
    product floor . At the end of the process
    completed units shipped out as soon as
  • But less inventory has also some risk if a
    problem arises there is no safety net.

Fail- Safe methods
  • The same as poka-yoke, when safeguards are built
    into a process to reduce or eliminate the
    potential errors.
  • The contact method identifies product defects by
    testing the product's shape, size, color, or
    other physical attributes.
  • The fixed-value (or constant number) method
    alerts the operator if a certain number of
    movements are not made.
  • The motion-step (or sequence) method determines
    whether the prescribed steps of the process have
    been followed.
  • Alarm if the weight of a packaged item is too
  • ATM signal ifthe card is left in the machine

Personnel/Organizational Elements
  • Workers as assets
  • Cross-trained workers
  • Continuous improvement
  • Cost accounting
  • Leadership/project management

Manufacturing Planning and Control
  • Level loading
  • Pull systems
  • Visual systems
  • Close vendor relationships
  • Reduced transaction processing
  • Preventive maintenance

Level loading
  • Mixed model sequencing
  • Choice of sequencing (minimal setup cost, or
  • The number of cycles per day smallest integer
  • Number of units daliy demand divided by number
    of cycles

Pull/Push Systems
  • Pull system System for moving work where a
    workstation pulls output from the preceding
    station as needed. (e.g. Kanban)
  • Push system System for moving work where output
    is pushed to the next station as it is completed

Kanban Production Control System
  • Kanban Card or other device that communicates
    demand for work or materials from the preceding
  • Kanban is the Japanese word meaning signal or
    visible record
  • Paperless production control system
  • Authority to pull, or produce comes from a
    downstream process.

Close vendor relatonship
  • JIT
  • Frequent small delivers
  • Deliver next to the workstation
  • No quality check
  • Local vendors
  • Tradtitonal
  • List of suppliers
  • Buyer play vendors off against each other
  • Price is the most important
  • No loyalty

Traditional Supplier Network
Figure 12.4a
Tiered Supplier Network
Figure 12.4b
First Tier Supplier
Second Tier Supplier
Third Tier Supplier
Preventive maintenance and housekeeping
  • 5S
  • Sort decide which item is needed
  • Straighten needed items can be assessed quickly
  • Sweep clean workplace
  • Standardize use standard intructions
  • Self discipline make sure that employees
    understand the need for uncluttered workplace

Thank you for your attention!
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