Research on the extrusion characteristics for the geometry of materials in material extrusion process using heating syringe.

The material extrusion process using a heated syringe in additive manufacturing offers the advantage of fabricating various materials with a single device while being cost-effective due to the ease of material storage and management. Additionally, since the material is sealed inside the syringe, it is isolated from external contamination, allowing for the processing of materials sensitive to environmental exposure. To optimize this process, this study aimed to identify the most effective material geometry and corresponding extrusion parameters. Thermoplastic polymers (PLA, TPU, ABS) were processed into chunk, disk, and pellet geometries, and extrusion experiments were conducted. The optimal parameters, determined through preliminary experiments, included extrusion temperatures of 200 °C, 207 °C, and 240 °C, and air pressures of 300 kPa, 550 kPa, and 550 kPa for PLA, TPU, and ABS, respectively. Experimental results demonstrated that chunk geometry achieved the highest extrusion ratio and the best quality of fabricated structures, with fewer defects such as bubbles. These findings highlight the importance of maximizing the material's contact area with the syringe wall while minimizing air exposure, providing a practical pathway to improve extrusion quality in the heated syringe additive manufacturing process.