Improving Process Capability of Cutting and Drilling Processes of Elevator Assembly Parts
Statistical process control (SPC) technique has become more and more often used for manufacturing process improvement with understanding the process and detecting the process variation. This paper presents a study from a small enterprise classified as OEM supply elevator assembly parts. A process capability study is performed for cutting and drilling processes in order to verify the process capable of consistently meeting the required specification and delivering quality products since increasing a number of rework parts. Why-why analysis was used to identify the root cause and the principles of Poka Yoke and jig & fixture design were then applied by design a measure gauge for cutting and drilling processes. After improvement, the result shows that the Cpk of cutting process increase from 0.19 to 2.72 while Cpk of drilling process also increase from 0.36 to 4.50. Since the Cpk is greater than 1.3 this means that both two processes have a capable to produce the output meet specification.