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Tovota Production System: Beyond Large-Scale Production by Taiichi Ohno 1978 Taiichi Ohno is credited with creating the just-in-time production system. He still feels today that the goal of Toyota is to shorten the time line, from the moment the customer places an order to the point where the cash is collected. He wants to further reduce that time line by removing non-value-added wastes. TheToyota Production System was born out of need. At the end of W.W.II, Toyoda Kiichiro, president of Toyoda Motor Company, said "Catch up with America in three years. Otherwise, the automobile industry of Japan will not survive." (They knew that one American worker produced approximately nine times as much as a Japanese worker.) So the Japanese looked at American mass production methods. What they foundwas a reliance on large lot production (optimal lot sizes) in order to create the greatest efficiencies, due to long set up times. Unfortunately, such methods would not work in Japan where demand was much smaller to begin with. So Ohno began looking at what to change. The basis of the Toyota Production System is absolute elimination of waste. The two pillars that this is based on are just-in-timeand autonomation. In justin-time production, a later process goes to an earlier process in the operation flow and withdraws only the number of parts needed, when they are needed. Autonomation refers to automating a process to include inspection. Human attention is necessary only when a defect is detected (the machine will stop and not continue until the problem is solved). Another primaryprinciple to the Toyota Production System is in determining profit margins. Instead of selling price = actual. cost + profit, Toyota understands that the consumer, not the manufacturer sets price. Therefore they use the formula of selling price - cost = profit. The goal now is cost reduction, not increasing selling price. In order to begin reducing costs, production leveling was instituted. For example,if a part is needed at a rate of 1000 per month, 40 parts a day should be made for 25 days. To go further, if there are 480 minuets per workday, one part should be made every 12 minutes, and to produce more would create an overstock. Ohno decided that establishing production flow and a way to maintain a constant supply of raw materials was the way Japanese production should be operated.

Toimprove process flow, Ohno decided that instead of putting the machines of one process together (i.e. all the lathes together, all the presses together, etc.) and having to carry parts back and forth between processes, he would lay out the plant according to the operation flow. He then assigned one worker to more than one machine (Japanese unions are not divided by function). Workers disliked beingforced to become multi-skilled in the beginning, but again, necessity is the mother of invention and Japanese workers realized that they must adjust or lose the race against the Americans. Thus the theory of "one operator, many processes" was born. This system increases production efficiency 2-3 times over "one operator, one process" which mass production required. The Toyota Production Systemevolved using a process called the "five whys." By asking why five times and answering each time, the real cause of a problem can be discovered. Often root causes are hidden under more obvious symptoms, and only by unpeeling the layers of the problem can the root be found. "Why can one person at Toyota Motors operate only one machine when one person can operate 40-45 looms at the Toyota textileplant?" The answer was found to be because machines at Toyota Motor didn't stop when machining was done. To this response came the birth of autonomation. Repeatedly asking why is the scientific basis of the Toyota system. Evolution of the Toyota Production System The Toyota Production System relies on elimination of waste as essential. The preliminary step of the Toyota Production System is to...