Implementation of DMIAC Methodology to Improve Process Capability in Needle Bearing Manufacturing Company: A Case Study

Abstract

This paper presents a case study done in bearing manufacturing company for improving process capability of cage manufacturing section of the company. This objective is accomplished by the application of DMAIC methodology to quality enhancement research work in the particular needle bearing manufacturing industry. Paper presents Six Sigma approach through five different phases of DMAIC methodology which are: Define, Measure, Analyze, Improve, and Control (DMAIC). For defining critical to quality parameter, rejection data of last one year was taken from red bin kept in rejection area. From the collected data, it is observed that there were ten types of rejection generally occurred while inspection of bearing and as per the count of rejection data Pareto analysis was done. From Pareto analysis it is observed that there were only two main rejections which were responsible for 70% of total rejection. These both rejection types were related to pocket size of bearing only. For the undertaken project SIPOC and ARMI (Approval, Resource, Member, Interested party) diagram was formed to fix responsibility for the project work. Current level of process capability and Sigma level were calculated in measure phase and histogram chart was formed with the help of Minitab software. Then in analyze phase Root cause
analysis was done by forming fish bone diagram and accordingly Failure Mode Effect Analysis(FMEA) was done to find out most vital causes for these particular types of rejection. Within analysis phase itself all key process input variable and key process output variables are examined and shown in process flowchart against each step of process. During improvement step, Design of Experiment (L-27 Orthogonal Array) was applied on welding parameters responsible for pocket formation of welding cage. Accordingly ANOVA was used to find out significant parameter for the rejection. To find out other vital issue related to rejection along with their possible solution, brain storming session was arranged consequently some inherent vital issues were came out which later on solved by the company. After implementation of finding of DOE and the brainstorming session it is observed that the process capability of the system was improve and at the same time Sigma level of the process also enhances significantly. Hence this research work shows the importance of Six sigma and its application in various medium scale company through DMAIC methodology.