Multi-energy field-assisted plasticization for enhanced melt flow and heating efficiency

• Multi-energy field-assisted plasticization mechanism with ultrasonic & mechanical vibrations. • Multi-physics coupling model was developed. • Melt flowability modifies up to 16.42 %. • Heating rate and phase transition efficiency strengthen up to 13.28 % and 39.67 %, respectively. The plasticizing unit plays a critical role in both the melt state and processing efficiency of continuous thermal processing lines. However, conventional screw plasticizing systems can cause shear damage to polymers, while plunger-based systems suffer from inadequate mixing and poor phase transition efficiency. The vibration-assisted technology has emerged as a promising approach to address these problems. In this study, we invented a multi-energy field-assisted plasticization (MEFAP) method that integrated ultrasonic and mechanical vibration effects within the plasticization unit. An injection molding machine was specially presented based on the MEFAP method. A multi-physics coupling model was developed by considering ultrasonic plasticizing heating, fluid-solid coupling, and acoustic streaming theories to investigate the internal flow dynamics and phase transition mechanisms. Experiments were conducted to validate the real plasticization performance. The results demonstrate that the MEFAP method can increase the average flow velocity to 136.06 mm·s -1 and the phase transition efficiency to 39.67 %. Compared to no-vibration condition, it modifies the apparent viscosity and heating rate by up to 16.42 % and 13.28 %, respectively, which is higher than that of the single ultrasonic vibration or mechanical vibration. It also exhibits a lower energy consumption compared with the no-vibration condition. In conclusion, the MEFAP method offers significant advantages in melt flowability enhancement, heating performance improvement, and energy consumption reduction, highlighting its potential for various thermal processing technologies.