The cost minimization and manpower deployment to SPC in a multistage manufacturing system

This article proposes an algorithm for deploying manpower to a statistical process control (SPC) system that monitors a multistage manufacturing system. The algorithm minimizes the expected total cost by optimizing the amount of allocated manpower in the SPC system (referred to as an M-SPC system), as well as the sample sizes, sampling intervals and control limits of the control charts. It also takes into account the probability distribution of the random process shifts at each process stage. Numerical studies show that the M-SPC system can reduce the total cost by about 75 percent, on average, compared to the traditional SPC system. It is also found that, in most of the traditional SPC systems, the allocated amount of manpower is far less than needed. This implies that the total cost can be significantly reduced with more manpower. Furthermore, the M-SPC system can be utilized and understood as easily as the traditional SPC system by shop floor operators. Some useful guidelines are provided to aid users in allocating the appropriate amount of manpower to different systems. Keywords. Quality control: Control chart; Statistical process control: Multistage manufacturing system; Manpower deployment: Loss function