Driving Sustainable Industrial Innovation Through PDCA-Based Process Capability Enhancement in Automotive Component Manufacture

Company X, as an automotive component manufacture and supplier, faced technical challenges in the form of dimensional instability during the transition phase from tool fabrication (Dies) to mass production of the 14233-68P01 aluminum series parts with the main problem being the accuracy of the part which is highly fluctuating. Through initial inspection of eight critical quality points, it was found that Point No. 7 (Surface) has a process capability index value (Cpk) of -1.04 which indicates that the process is far outside the control limits and fails to meet the customer's technical specifications (Cpk ≥ 1.33), where periodic monitoring data from June to September 2025 confirmed a consistent deviation that significantly exceeds the Upper Specification Limit (USL) threshold of 5.7 mm. This study aims to restore process stability through the implementation of the Plan-Do-Check-Act (PDCA) cycle integrated with the Statistical Process Control (SPC) and Process Capability Analysis (Cp & Cpk) methodologies which begins with the Plan stage through root cause analysis using Fishbone diagrams to identify tool degradation in the stamping dies unit and the material springback phenomenon as the main factors. Furthermore, in the Do stage, strategic improvement measures are carried out through innovative technical modifications to the die design, such as Die welding work, program creation and machining of the Die improvement area, which are then evaluated in the Check stage to verify the effectiveness of these improvement actions before finally entering the Act stage by standardizing procedures with routine preventive maintenance to maintain long-term quality consistency. The results of the post-improvement evaluation show a significant improvement in process performance with a Cpk value that has changed to 1.36, which proves a real contribution in providing technical references for aluminum material control for a global automotive industry, while providing a positive impact on manufacturing sustainability through reducing rework rates and eliminating defective products.