Achievement of Composite Vibration‐Assisted Plasticizing in Injection Molding: Equipment Design and Product Quality Investigation

Conventional injection molding (CIM) requires extreme process parameters to achieve high‐quality filling of intricate microstructured cavities. While vibration‐assisted techniques show promise in improving melt flowability, but with limited investigation into vibratory plasticization itself and its impact on final part quality. We proposed a novel composite vibration‐assisted plasticizing (CVAP) method, which integrated ultrasonic and mechanical vibrations into the plasticizing unit. A dedicated device was designed and fabricated, featuring symmetrically arranged ultrasonic and mechanical actuators aligned perpendicular to the melt flow direction. The plasticizing and filling performance was evaluated by molding ballpoints with a microhole feature, using product weight consistency and dimensional accuracy as key metrics. Results demonstrate that CVAP significantly enhances filling performance compared to CIM and single‐mode vibration. Increasing the mechanical vibration amplitude proves most effective, raising the average product weight from 44.40 to 52.73 mg and modifying weight repeatability accuracy from 14.31% to 5.40%. Under applied parameters (ultrasonic amplitude of 50.76 μm, mechanical frequency of 2.5 Hz, mechanical amplitude of 10 mm), CVAP achieves the highest weight repeatability (2.71%) and dimensional accuracy (98.03%). This work demonstrates the feasibility of CVAP as a promising strategy and provides preliminary evidence of its synergistic effect.