Injection molding process optimization for PMMA lens manufacturing through machine tonnage migration: a comparative industrial study
Year: 2026
Type: article
Abstract: The manufacturing of optical automotive lamp lenses using polymethyl methacrylate (PMMA) requires precise control of injection molding parameters to ensure consistent visual quality and production efficiency. This study investigates the optimization of injection molding process parameters for an automotive headlamp lens (PMMA Clear Sumipex MH011, two-cavity mold) through machine migration from a 450-ton injection molding machine to a Toshiba EC650SX III 650-ton machine. Under the initial production conditions, the limited screw drive capacity of the 450-ton machine resulted in excessive charging torque, requiring barrel temperatures up to 291°C to maintain stable plastication. Process optimization included runner system modification, barrel temperature reconfiguration, and multistage injection speed optimization. Production performance was evaluated using actual industrial data collected over a continuous 24-hour production period. The optimized process reduced runner weight by 27% (53.66 g to 39.20 g), shortened fill time from 7.61 s to 4.88 s, and decreased the actual cycle time from 69.0 s to 61.9 s, corresponding to an increase in theoretical production rate from approximately 52 to 58 shots/h. Actual 24-hour gross production increased from 2,406 to 2,496 pieces. Product yield also improved from 88.23% to 93.72%, while silver streak defects were reduced from 153 to 26 occurrences (83% reduction). A negative binomial regression analysis showed a significant association between machine/process configuration and silver streak occurrence (IRR = 5.89, p 0.001). The results indicate that combining higher machine capacity with optimized processing parameters improves production efficiency, process stability, and visual quality performance in industrial PMMA injection molding.
Source: Jurnal POLIMESIN
Institution: Universitas Buana Perjuangan Karawang
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7225876396