Statistical Process Control of Batch Weighments
Richard K. Peelle · Ceramic engineering and science proceedings · 2008
Statistical Process Control (SPC) is an important tool used by Corning in the establishment and maintenance of accurate batch weighments. The control systems used by our latest batch system designs incorporate PLC controls. In addition to controlling the weighing process, the PLC serves as a data collector and interface to an SPC computer. The data transmitted includes the set points or targets as well as the individual weight of each ingredient in each batch. The SPC computer massages this data and produces charts which indicate the stability of the process. The charts are produced on an ingredient basis and the standard Western Electric (WECO) rules for nonnatural error distributions are applied and out-of-control points identified. Operators and engineers use this information to take corrective action and to fine tune the system.