Perpustakaan Digital ITB

PT Indonesia TRC Industry is a manufacturing company that produces components made from rubber, metal, and plastic. One of the quality problems in the Roll Press Department is the high number of not good (NG) products in the rubber press process. Based on February 2026 data, the NG percentage in the Roll Press Department reached 9.02%, while the company target was 3.17%. Priority analysis showed that the Roller Paper Eject part contributed the highest number of NG products, with outer tear as the dominant defect. Under the existing condition, this part produced 809 NG pieces out of 8,400 actual production pieces per shift, or 9.63%. This study aims to design a process improvement proposal for the rubber press process to reduce NG products with outer tear defects on the Roller Paper Eject part. The problem-solving process was carried out using the DMAIC approach through the Define, Measure, Analyze, Improve, and Control stages. The Define stage was used to define the problem, scope, target, primary metric, and project focus through a project charter. The Measure stage collected data on machine start interval, panel temperature, mold temperature, and the number of NG products as the response. The Analyze stage was conducted using a fishbone diagram, Five Whys, and Design of Experiment (DOE). The Improve stage was carried out through Response Optimization as a further analysis within DOE to determine the parameter combination that minimizes the number of NG products. The Control stage was conducted by preparing process control recommendations in the form of a proposed work instruction draft. The results showed that the main improvement parameters were machine start interval and mold temperature. Based on the Response Optimization results, the optimal combination was a machine start interval of 186 seconds and a mold temperature of 162.655°C. This combination produced a predicted NG value of 1.35472 pieces out of 200 pieces, resulting in an optimized NG percentage of 0.68%. This indicates a potential NG reduction from the existing condition of 9.63% to 0.68%. The proposed improvements include setting the machine start interval, controlling mold temperature, adjusting panel and mold temperature, and preparing a proposed work instruction draft. The financial impact analysis showed that the proposal is potentially feasible, with an initial investment of Rp12,766,800, an NPV of Rp5,345,871, a monthly IRR of 6.36%, a BCR of 1.42, and a payback period of 9 months.