Caffrey, Stephen J. (1990, ASQC) Eastman Kodak Co., Rochester, NY
In many chemical industries, materials are produced in batches, and there is, of course, some amount of batch-to-batch variability. A common thrust at Kodak, as in many companies, is to reduce variability. In order to accomplish this, especially in a batch-oriented environment, adjustments are often made to already-produced batches. These adjusted batches are then sent to the next operation and eventually a finished product results. The goal of this adjustment is to provide a more uniform inboming material (on a batch-to-batch basis) for the subsequent manufacturing step. However, it is possible that what appears to be optimal for one department is not really providing a substantial improvement for use in the subsequent operation. This paper presents a case study to illustrate two points. First, the entire flow of product should be considered when determining what strategies should be used for adjustment. Second, if adjustment is necessary, different adjustment strategies should be studied in order to determine what strategy, if any, will increase the uniformity of the finished product. Simulation and a graphical presentation are used to illustrate the effectiveness of various alternative strategies. The method of adjustment currently used, and variations around it, will be contrasted with one referred to as Aiphamin. Aiphamin was developed by R. Schleusener and J. Baylis of the Kodak Colorado Division of Eastman Kodak. Under certain conditions one can show that the optimal adjustment (the one improving batch-to-batch uniformity the most) is a function of the amount of batch-to-batch variability and the measurement variability.
Case study,Chemical and process industries