Optimasi Parameter Proses Vacuum Forming Lembaran PET dengan Metode Taguchi pada Mesin Plastic Vacuum Forming Otomatis

Abstract

Vacuum forming is a thermoforming process whose dimensional accuracy is strongly affected by process conditions, particularly sheet temperature, heating time, and vacuum application. This study focuses on optimizing the process parameters of an Arduino-based automatic plastic vacuum forming machine for Polyethylene Terephthalate (PET) sheets. The machine was designed, fabricated, assembled, and tested using PET sheets with thicknesses of 0.3, 0.5, and 0.75 mm. For the Taguchi optimization, three control factors were selected: heating temperature (100, 105, and 110 °C), heating time (20, 23, and 25 min), and vacuum time (10, 12, and 14 s). A three-level L9 orthogonal array was used. The response was dimensional deviation from the mold dimensions of 112 × 170 × 20 mm, with the characteristic Smaller-is-Better. For the 0.5-mm sheet, recalculation of the experimental data shows that the optimum combination based on the response means is 100 °C, 23 min, and 10 s (A1B2C1). The relative contributions to the composite dimensional-deviation response were 35.30% for heating time, 10.28% for temperature, and 4.26% for vacuum time, while the remaining variation was 50.15%. Across the three sheet thicknesses, the reported optimum settings were 100 °C–20 min–14 s for 0.3 mm, 100 °C–23 min–10 s for 0.5 mm, and 110 °C–30 min–10 s for 0.75 mm. The results confirm that PET thickness changes the thermal forming requirement and that the Taguchi method provides a systematic approach for selecting process settings with a limited number of experiments.