12. lean operations

JUST IN TIME

this sets out to cut costs by reducing the amount of goods a firm holds in stock

it produces and delivers goods JIT

PUSH VS PULL SYSTEMS

  • push- work is pushed to the next station as soon as it is completed

  • pull- workstation pulls output from the proceding station when it is needed the output of thr final operation is pulled by customer demand or the master scheduel

RULE OF INVENTORY REDUCTION

This is the idea that inventories hide issues

reducing inventories can reveal the organisations issues

LEAN PRODUCTION

JIT is an element of lean production. it looks at eliminating all waste that doesn’t add value to develop a faster, dependable and higher quality operation that operates at a lower cost

JIT AND LEAN

these originate from the market of Toyota who developed the Toyota production system which eliminates all waste that doesnt add value from a consumers point of view

we have 7 forms of waste

  1. over production

  1. waiting times

  2. transport

  3. overprocessing

  4. inventory

  5. motion

  6. defects/inspection.

5ss is a simple method to organise work areas, focusing on a visual order, cleanliness and standardisation

  • sort

  • straighten

  • shine

  • standardise

  • sustain

there are 2 methods of eliminating waste

  1. involving everyone this is called respect for humans system, it encourages team based problem solving and personal responsibility

  2. continous improvement- its principles are

    1. mindset of improvement

    2. try again and again

    3. think

    4. work in teams

    5. recognise that improvement has no limits

KANBAN

this is the japanese word for CARD this is an authorisation for the next container of material to be produced, a series of kanbans pulls materials through the process

when a producer and user arent in visual contact a card can be used, normaly each card controls specific quantities of parts. they provide direct control and limit on the amout of work in processes between cells

we need to know the lead times needed to produce a container of parts and the saftey stock needed

the number of kanban is the demand during lead time+saftey stock'/size of container

TIMES

  1. takt- rate of production required to meet customer demand, the max time available to produce one unit in order to satisfy customer demand

    takt time=total work time available/units required to satisfy the customer demand

  2. cycle time- the actual rate of production

    production time available/number of units produced

  3. throughput time- the time it takes for one unit to go thorugh production processess

    throughput time=order dispatch-order releases

  4. lead time- time taken for one unit to go thorugh the production process

    lead time= order delivered-order received

takt and cycle times can be compared to understand the current status of production capabilities