A major element of Western manufacturing’s inventory was that which we held in case of problems. We held safety stocks to allow us to continue manufacturing should some of the components or raw materials in our stores be found to be defective.
Ohno and his colleagues, ironically, had listened to the American quality gurus, W. Edwards Deming and Joseph Juran, who had advised Japanese industry as it recovered after World War II. Among the key concepts learned by the Japanese and neglected for many years in the West were:
Deming’s teaching that we cannot inspect quality in a product but must build it into the manufacturing process.
Juran’s definition of the internal customer. If we each give service to our internal customer then we will ultimately take care of the end customer.
By applying these teachings and aggressively eliminating all sources of non-compliance the Japanese moved quality onto a completely different plane. Where the West continued to measure percentage defect rates our competitors were working in parts per million.
As well as addressing the manufacturing processes, we learned that the JIT approach considered other contributors to improved quality. Is the component designed in such a way as to make it easy to produce or can we simplify it and reduce the chances of a defect? We began to think of «design for manufacture» and combining the previously separate functions of design engineering and production engineering.
We heard about things called «quality circles» where people in different areas of the business came together to investigate problems and work as a team to solve them – rather than follow our own approach of each area attempting to blame another. Perhaps most disturbingly we heard that inspectors were a thing of the past. All had now been trained as quality engineers and were in fact working as process improvement specialists so that their old function was no longer required.