Calculating and plotting contour curves of a response surface

The main goal of manufacturing control is to keep production process optimal all way along. In order to optimize a process, an approach such as evolutionary operation program (EVOP) or response surface methodology (RSM) is usually recommended. In EVOP, experimental designs and improvements are introduced, while an ongoing full-scale manufacturing process keeps producing satisfied results. The concept is that process improvement should not interrupt production. The main idea of RSM is to use a sequence of designed experiments to obtain an optimal response. Though the RSM results can be acquired, the process analyzer still has problems with dealing the calculation and plotting of the contour curve. Normally the response surface curve is oval-like, thus a solution of control conditions to the contour is an implicit function. Its solving calculation involves an iterative procedure. This article is to provide an explicit calculation method to find all condition combinations for a specific contour. Some features of the RSM contour are discussed as well in this article. © 2015, Chinese Society for Quality. All rights reserved.