Track: Lean Six Sigma Case Study Competition

Abstract

This paper explains our project about a six sigma application to improve a PVC pipe production process. We began with introducing the company that we chose which is the National Industry Company (NIC) and their production process of both PVC pipes and fittings. Then we used the DMAIC methodology to define the problem that they are facing which is defective pipes and fittings and in the measure phase we collected data regarding both productions and calculated the average defective pipes per month with their associated costs and decided to focus on pipe production lines. After that, in the analyze phase, we looked into the factors and found the root cause of the defective pipes are torque and feeder speed levels. In addition, we used Minitab to draw X bar-R charts and found that the process was out of control, hence we used contour plots to find the optimal settings of both torque and feeder speed levels. Finally, in the improve phase, we removed the out of control points that were out of the optimal settings found earlier and the process became in control indicating 89% improvements. Finally, we provided an out of control action plan for when an outlier appears on the X bar charts during the monitoring of the process.

Keywords: Pipes, defect rate, torque, feeder speed.