It is a fact that no two products are exactly alike because of slight differences in materials, workers, machines, tools and other factors. These are called common or random causes of variation. Common causes of variation are based on random causes that we cannot identify. The combination of Cp and Cpk is used extensively because it shows both the potential process capabilities. The Process Capability Ratio (PCR) and Process Capability Index (Cpk) for a kick starter gear drive (depth of pitch problem) were computed after stabilizing the manufacturing process. Data were taken from the manufacturing process and the and R control charts were plotted to find whether the processes are within statistical control or out of statistical control. The process capability analysis was done to find out the effectiveness of the processes. It was found that 0.465% of kick starter gear due to depth of pitch was beyond the control limits, which is really a major concern for the industry.

The purpose of implementing the Statistical Process Control (SPC) is to minimize the production costs by using “make it right the first time” program. This type of program can eliminate costs associated with making, finding and repairing or scrapping substandard products. It aims to attain a consistency of products and services that will meet production specifications and customer expectations. By reducing the product variability to a level that is well within specifications, the process output will match the desired design quality. This consistency leads to process predictability, which benefits the company by helping management meet quality targets.

Mechanical Engineering Journal, Process Capability Index (Cpk), and R Control charts, Process Capability Ratio (PCR), Depth of pitch manufacturing industry.