Efficient injection moulding using active vacuum venting

Abstract

Injection moulding is a leading polymer manufacturing technique that involves melting plastic material, injecting it into a cavity, and cooling it to solidify into the desired shape. Due to the complexity of many moulded parts, air may be trapped in dead-end areas of the cavities, leading to a range of quality issues ranging from cosmetic defects to functional failures, resulting in significant scrap rates. To ensure consistent part quality, venting plays a fundamental role. While passive venting is commonly employed, complex parts necessitate more efficient setups, called active vacuum venting systems (AVVSs). Conventional AVVSs involve bulky and costly equipment. This study proposes a sustainable assessment of a novel AVVS by focusing on its energy consumption. While the AVVS requires compressed air to generate a vacuum, it offsets this energy consumption by achieving a 9-17% shorter cycle-time. This leads to an overall 8-12% energy consumption reduction while increasing productivity. By comparing it to a moulding process without venting, this research evaluates the feasibility and benefits of implementing this AVVS to enhance energy efficiency, productivity, and product quality. Optimal injection parameters for both scenarios are established, and then the injection speeds are increased to assess the system’s performance under higher productivity settings.