Just in Time (JIT)

I promised you a post on JIT, a truly fascinating product of the Japanese mind! The over-riding objectives are zero inventory, zero queues ( a queue is merely inventory in the form of work in progress) and zero defect (right first time).

They took these objectives and put them into a production environment with some very interesting results. I can only whet your appetite. If I succeed, read a book on JIT, it is truly fascinating and thought provoking. And by the way, most of the principles can be applied to all forms of endeavour, not just to factories (including for example, our own auditing practice).

Concept No.1 Zero queues at all work stations.

This requires ensuring that you plan your workflows and workstations so that work does not pile up in front of any workstation simply because the one before works faster. You may, for example, need two slow workstations for every fast one feeding them.

It also requires a pull system of feeding work rather than a push system. Think of it this way - there are two ways of feeding a ball of wool through a keyhole. You can keep shoving it in from one side and eventually it may start coming out the other. Or you can carefully feed an end through, then go around to the other side and pull the rest through. That's the pull system.

In Japan they invented the Kan Ban which is a token that the following machine's operator (No 2) passes back to the preceding operator (No 1) when they're ready to receive the next item. But forget the Kan Ban, we don't want to get too complicated here. Just see it this way. When No 2 takes the item from No 1, then No 1 immediately starts to process another item ready for No 2. That may, of course mean that No 1 has to wait for No 2 but that simply indicates that the production resources are not balanced and more work needs to be done in that regard.

 Concept No 2. If a workstation stops, everything stops.

This is an inevitable consequence of zero queues, but it has value. In Japan, when the entire production line stops, all energies are put into finding the problem, sorting it out and getting it going again. Everybody who can contribute does so (they have nothing else to do anyway).

Concept No 3. Zero defects.

Imagine in a Western factory, the first workstation produce a batch of faulty product. This batch passes through all the following workstations and ends up eventually at Quality Control where the defect is detected and the batch is scrapped. All of that production time has been wasted.

In JIT, every workstation inspects/tests the item from the preceding workstation before processing it. If it is faulty, the entire production line is stopped and everyone gathers around to solve the problem. That way no inferior item is processed and there is no waste of prodution resources. Clearly there is no need for a QC department at the end of the line except to test the work of the last workstation.

Concept No 4 Batch size will be one

Clearly the bigger the batch, the more items will be in the production line at any one time and the greater will be the inventory of Work in Progress, the longer the overall production time (because now there will be waiting time within the batch as well). Also, any faulty production will cause the entire batch to be faulty, so the smaller the batch, the less wastage.

Concept No 5 Zero raw material inventories

The raw materials from the suppliers must arrive just at the time that they are needed by the production line and in frequent small deliveries. This requires the co-operation of the suppliers and usually, that they also adopt the Just-in-time methodology.

Concept No 6 Zero finished goods inventories

Finished goods will be collected by, or delivered to, the customers just as they come off the production line. Note that no final inspection is needed because there are zero defects.

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Great concepts, food for thought

When I first got involved in JIT, I thought Wow, this is amazing, but it will never work here. Then I got to thinking. Take a great idea and let it change your way of thinking. You might not adopt it (either partially or in its entirety) but if it gets you thinking differently about how you do things, then it's done the job. 

For instance. Back when I owned my own factory, I used to use the push system of feeding the production line and there was always a long delay between loading a job and it coming out the other end. I should have pulled it through.

Another, entirely different great idea that should change your way of thinking is the "positive cash flow from day one" way of planning a new venture. It is rarely possible to achieve this entirely, but by focussing on positive cash flow from day one, it is amazing what you can achieve.

For me, the one word that jumps out of JIT is the word "zero". If you constantly aim for perfection you will constantly improve.

Should you wish to make an appointment, please feel free to visit Derek's diary and book a time that suits you.

 


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