鋳鉄鋳物工場における標準的品質管理システムの開発

抄録

  As is well known quality control is very important in foundries, especially in the foundries of castings for automobile parts whose properties such as mechanical strength and dimensional tolerance are specified by the customers to extremely narrow ranges. For the purpose of developing the computer system of quality control in gray iron foundries, critical factors for quality control in the foundries using high or low frequency induction melting furnaces were first selected. Standardization of a system of quality control in foundry was found difficult, because of the complication of the manufacturing processes interacting with each other. Besides an attempt was made to develop a computer system for the analysis of casting defects occurring daily in the foundries. A system with the following features was developed.
  1) All data obtained daily from various processes in a foundry are stored in a floppy disk as the data base. The data can subsequently be retrieved and checked and/or printed out whenever necessary.
  2) Data such as materials consumption, mechanical test results or chemical analysis can be displayed as histograms, X-Rs diagrams, X-R diagrams or correlation scatter diagrams with regression curves. Histograms or Pareto's curves can be constructed for a specific part, a group of castings or a type of iron to aid casting defect analysis.
  The system enables a single engineer to analize an enormous amount of daily data in a foundry and to make appropriate decision on the process control.