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| The creation of Taiichi Ohno of Toyota in the early 1950's, the Just In Time (JIT) production system or technique is the coordinated manufacture of components or products so that they arrive at their destination "Just in Time". This meant that only the part that was required at that time would be manufactured, not a batch of parts. Therefore, the beginning of the single unit manufacturing system. |
| Since only one unit was require at any time, the work in progress (WIP) is reduced to the number of workers in the production system. Each person performs work on the product (adds value) and hands it to the next worker. The product is never disposed to a table or bin, then picked up by the next worker, therefore no wasted time in the disposal and pick up activities. This is actually not as difficult to coordinate as one might think. Slower operations are set up in multiples to absorb the incoming production. Faster operations are combined to make the production time greater and evenly divisible into the following operation's production time. |
| The greatest savings is in the JIT "Bumping" system. This method of JIT production eliminates the workers "ownership" of an operation. Even in the standard JIT system, after a worker hands the part to the next worker, it is possible that they would wait for the previous operations worker to complete their task before handing it to them. This is eliminated in the JIT "Bumping" system. Instead of requiring an worker to wait for the operation to be completed, they simply take over the completion of the operation. |
| For example, if the operation in question is threading a set of 4 bolts on a flange and only 2 have been started, there is no need for the next worker to wait, they would take the remaining 2 bolts for their co-worker and finish the operation. With this procedure, the production line or cell would have the worker perform the final operation (dispose the finished product) move to their co-worker and "bump" them or take over the operation being performed. That worker would bump their co-worker, and so on until the first worker would be bumped and they would collect the first parts and start a new assembly. |
| One of the flaws in the standard JIT system is when there is a problem with one of the operations, the whole line must stop. With the bumping system, the worker with the problem would back out of the production line and correct the problem, then re-enter the line. If the operation involves a machine, the spare machine is used. The only full line stoppage occurs in the case of large, expensive equipment that would not be duplicated (i.e. a paint booth in a trailer manufacturer). |
Information on the JIT Workshop
Lean Manufacturing
Value Stream Mapping