Analysis of Quality Control for Automatic Transmission Products MCVT Model By Six Sigma Approach at PT HPPM, Indonesia

PT HPPM is a manufacturing company engaged in the automotive sector. The products produced include Automatic Transmission (ATM), Engine Valve (EV), Four Wheel Drive (4WD), and Stell Belt, which are marketed at home and abroad. In carrying out its production activities, PT HPPM has guidelines for controlling its products' quality to compete in the automotive industry, including ATM products with the MCVT (Medium Continuously Variable Transmission) model. The method used in the quality control analysis of this research is Six Sigma, a vision of quality improvement towards a target of 3,4 failures per million opportunities for every transaction of goods and services, Gasperz (2005). To apply the Six Sigma concept, a measurement method is needed to assist the implementation of Six Sigma in the company. There are five steps in this method's stages, namely DMAIC (Define, Measure, Analyze, Improve, Control). There are four potential Critical To Quality (CTQ) that cause the product to become defective or fail in the MCVT model, namely NG Leak, NG Gata, NG Circlip, and NG OPC. The highest defect is NG Leak defect, 127 units with a percentage of 45.68% of the total number of defects produced—then followed by defects NG Gata with 79 units with a percentage of 28.42%. Meanwhile, another defect is NG Circlip, with 62 units with a percentage of 22.30%, then NG OPC as many as ten units with a percentage of 3.60%.  By using the Six Sigma method and the DMAIC step (Define, Measure, Analyze, Improve, Control), it can be seen that the quality of MCVT products in the Main Line 1 process is good, which is at the level of 4,876 sigma with 370 Defect Per Million Opportunity (DPMO). From the Define stage by mapping and identifying problems to find out the causes of defective products, the Measure Stage by calculating the stability of the poses using the SPC method to determine the Proportion, CL, UCL, and LCL and calculating the process capability to determine the sigma level value and the DPMO value. The Analyze stage identifies the source of the problem with the Fishbone Diagram, the Improve stage looks for solutions using the 5W1H method, then Control to maintain and maintain process improvements. The results showed a decrease in the DPMO value from 383 units to 370 and an increase in the sigma level value from 4,868 to 4,876. This shows that the company has been able to implement a good quality control system