Experimental analysis of process parameters in semi-automatic blow molding of PET bottles: a case study at Universitas Negeri Malang product

Obaja Eden Sentosa Riyanto; Dewi Izzatus Tsamroh; Ilham Akbar Wandoyo; Den Arsyah Pilar Pancayudha; Hikmal Faidillah

doi:10.30811/jpl.v24i1.8192

Experimental analysis of process parameters in semi-automatic blow molding of PET bottles: a case study at Universitas Negeri Malang product

Obaja Eden Sentosa Riyanto, Dewi Izzatus Tsamroh, Ilham Akbar Wandoyo, Den Arsyah Pilar Pancayudha, Hikmal Faidillah

Abstract

This research aims to analyze the effects of key process parameters on product quality and defects in the semi-automatic blow molding of Polyethylene Terephthalate (PET) bottles at Malang State University (UM). The background of this study stems from the increasing demand for high-quality PET packaging and the limited number of direct experimental studies on semi-automatic machines, with a limited number of tests. Most previous studies have emphasized model-based simulation and optimization, while practical studies that observe the relationship between process parameters and defect characteristics remain rare. Unlike simulation-based studies, this work is based on direct field experiments under stable, industry-relevant machine settings to evaluate product quality and production readiness for mass manufacturing. The research method was conducted through direct experiments using 12.5 g PET preforms and a 330 mL capacity two-cavity mold. The main variables tested included preform temperature (70°C and 80°C), blow delay time (0.30–0.50 s), and low-blow duration (0.20–0.50 s). Bottle quality was evaluated based on thickness measurements, dimensions, and visual analysis of defects such as wrinkles, collapses, and wall irregularities. The results showed that a preform temperature of 80 °C and a low-blow duration of 0.50 s produced bottles of the highest quality, characterized by uniform wall thickness, flat bases, and minimal defects. In contrast, low-temperature settings (70 °C) resulted in high viscosity, leading to deformation and wrinkles. This optimal combination of parameters was proven to improve bottle structure homogeneity and reduce dimensional shrinkage to <1%. This study emphasizes the importance of temperature and blow time control in achieving stable, efficient, and mass-oriented PET bottle production, while strengthening the role of universities in experimental manufacturing applied research.

Keywords

Bottles PET, blow molding, process optimization, preform temperature, semi-automatic machine

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DOI: http://dx.doi.org/10.30811/jpl.v24i1.8192