Messina, William S. (1988, ASQC) IBM Corporation, Tucson, AZ
The 1980s have seen a change in strategy in the way to complete economically in American industry. Previously, we competed through marketing and financial methods to achieve specified objectives; in today's economic climate this is not enough. Our competitors from the Pacific Basin (that is, Japan) have been using different modes to reach their stated objectives. They are using highly innovative manufacturing strategies, such as just-in-time (JIT) manufacturing, optimized process technology (OPT), and flexible manufacturing systems (FMS). As a result, American companies are starting to implement their own innovative strategies so that they might become world-class manufacturing enterprises, increase the quality of their goods, and increase their competitive position to meet stated objectives.
This paper will first examine one of the most common manufacturing strategies being implemented in American industry, namely JIT, through four of its most-common principles: reducing the economic order quantity, reducing set-up times, making the work force flexible, and balancing the line.
Then, the synergistic relationship between JIT and statistical quality control (SQC) will be explored. This relationship is based on the following four action principles: simplifying the process, eliminating waste, making problems visible, and creating a climate for continuous improvement.
The subject of what type of statistical methods is to be employed for JIT will be examined next. The important statistic that will be discussed in detail is process performance (Cpk). We will show its use in JIT manufacturing by relating it to parts per million (PPM) defect levels-a necessary requirement for this strategy to work. We will also develop the Messina cost function to show how Cpk is incorporated into determining what the true cost per part is for purchased parts and how it relates to the initial cost set by the vendor.
Finally, an overall strategy for JIT and SQC will be developed, based on the action principle of creating a climate for continuous improvement. The overall strategy will be developed by examining three phases of the product cycle: development, the vendor and original equipment manufacturer (OEM) relationship, and the manufacturing line.