正态过程下满足多重约束的CSP-2和Spk集成过程控制方案

单一过程控制工具只能满足一种约束需求,如连续抽样检验(CSP)方案只能满足质量约束,但生产过程控制需要同时满足多种约束需求.为同时满足质量、成本、第一类风险和第二类风险四种约束需求,提出CSP-2 (放宽的单水平连续抽样方案)和Spk(过程良率指数)集成过程控制方案.指出将检验成本转化为极限检验数的转化思路.发现了满足质量和成本约束的唯一可行的CSP-2等值面方案.建立了基于Spk估计精确分布的风险控制方案.集成控制方案运行时,CSP-2和Spk分别利用检验数据的计数信息和计量信息驱动方案运行.与CSP-2独立运行时相比,检验工作量没有增加.四种约束和集成控制方案参数之间一一对应.与传统CSP-2方案相比,各种约束需求下集成控制方案都获得了明显较好的接收曲线.

The integrated process control scheme by combining CSP-2 and Spk under multiple constraints for normally distributed process

The single process control tool can only be used to guarantee that one constraint is met during the process control, for example, the reduced continuous sampling plan (CSP-2) is applied to satisfy quality constraint. However, multiple constraints must be satisfied simultaneously during process control. To meet concurrently four constraints, quality, cost, the first kind of risk, and the second kind of risk, the integrated process control scheme between CSP-2 and S_pk (the process yield index) is proposed. A new idea is presented that the inspection cost is transferred into inspection capability limit. The sole feasible CSP-2 contour scheme under the specified quality and cost constraints is found. The risk control scheme is constructed based on the accurate distribution of the estimator of the index S_pk. During the operation of the integrated control scheme, the CSP-2 scheme is executed by utilizing the attribute information of the sample, the risk control scheme is conducted in use of the variable information of the sample. Comparing with the inspection scheme in CSP-2, the inspection workload for the integrated control scheme is not increased. There is a one-to-one correspondence between the values of the four constraints and the parameters of the integrated control scheme. The OC curves in the proposed scheme have larger slope than the inspection scheme in CSP-2 under various values of the multiple constraints.