Case Study: Use of Grease in Moulding to Prevent Corrosion and Increase Productivity with Fishbone Diagram Method at PT Tuffiadi Semesta

Corrosion of moulding components is one of the critical problems that has a direct impact on the efficiency of the production process and the quality of the mould. PT Tuffiadi Semesta faces the problem of decreased productivity due to mould damage caused by inaccurate use of grease as a protective lubricant. This research aims to identify the root cause of corrosion and develop an improvement strategy using the fishbone diagram method as a cause-and-effect analysis tool. The research approach used is a case study with qualitative methods through field observations, interviews, and literature studies. The results of the analysis show that the main factors causing corrosion include the mismatch of grease type with mould specifications, lack of operator understanding of lubrication procedures, and the absence of standard work standards related to mould maintenance. After validating the fishbone diagram, the company implemented improvements in the form of selecting the appropriate grease, training operators, and preparing lubrication SOPs. The implementation of these improvements resulted in a 15% increase in productivity and a 40% decrease in mould defect rate. These results show that the fishbone diagram method is effective in systematically identifying and resolving operational problems.