Boyle Bret M, Xiong Panupoan T, Mensch Tara E, Werder Timothy J, Miyake Garret M
Department of Chemistry, Colorado State University, Fort Collins, CO, United States.
Addit Manuf. 2019 Oct;29. doi: 10.1016/j.addma.2019.100811. Epub 2019 Aug 6.
Additive manufacturing promises to revolutionize manufacturing industries. However, 3D printing of novel build materials is currently limited by constraints inherent to printer designs. In this work, a bench-top powder melt extrusion (PME) 3D printer head was designed and fabricated to print parts directly from powder-based materials rather than filament. The final design of the PME printer head evolved from the Rich Rap Universal Pellet Extruder (RRUPE) design and was realized through an iterative approach. The PME printer was made possible by modifications to the funnel shape, pressure applied to the extrudate by the auger, and hot end structure. Through comparison of parts printed with the PME printer with those from a commercially available fused filament fabrication (FFF) 3D printer using common thermoplastics poly(lactide) (PLA), high impact poly (styrene) (HIPS), and acrylonitrile butadiene styrene (ABS) powders (< 1 mm in diameter), evaluation of the printer performance was performed. For each build material, the PME printed objects show comparable viscoelastic properties by dynamic mechanical analysis (DMA) to those of the FFF objects. However, due to a significant difference in printer resolution between PME (X-Y resolution of 0.8 mm and a Z-layer height calibrated to 0.1 mm) and FFF (X-Y resolution of 0.4 mm and a Z-layer height of 0.18 mm), as well as, an inherently more inconsistent feed of build material for PME than FFF, the resulting print quality, determined by a dimensional analysis and surface roughness comparisons, of the PME printed objects was lower than that of the FFF printed parts based on the print layer uniformity and structure. Further, due to the poorer print resolution and inherent inconsistent build material feed of the PME, the bulk tensile strength and Young's moduli of the objects printed by PME were lower and more inconsistent (49.2 ± 10.7 MPa and 1620 ± 375 MPa, respectively) than those of FFF printed objects (57.7 ± 2.31 MPa and 2160 ± 179 MPa, respectively). Nevertheless, PME print methods promise an opportunity to provide a platform on which it is possible to rapidly prototype a myriad of thermoplastic materials for 3D printing.
增材制造有望给制造业带来变革。然而，新型建筑材料的3D打印目前受到打印机设计固有局限的制约。在这项工作中，设计并制造了一种台式粉末熔融挤出（PME）3D打印头，以便直接从粉末基材料而非长丝打印部件。PME打印头的最终设计源自Rich Rap通用颗粒挤出机（RRUPE）设计，并通过迭代方法得以实现。通过对漏斗形状、螺旋输送器施加于挤出物的压力以及热端结构进行改进，使得PME打印机成为可能。通过将使用PME打印机打印的部件与使用常见热塑性塑料聚乳酸（PLA）、高抗冲聚苯乙烯（HIPS）和丙烯腈-丁二烯-苯乙烯（ABS）粉末（直径小于1毫米）的市售熔融长丝制造（FFF）3D打印机打印的部件进行比较，对打印机性能进行了评估。对于每种建筑材料，通过动态力学分析（DMA），PME打印的物体显示出与FFF物体相当的粘弹性特性。然而，由于PME（X-Y分辨率为0.8毫米，Z层高度校准为0.1毫米）和FFF（X-Y分辨率为0.4毫米，Z层高度为0.18毫米）在打印机分辨率上存在显著差异，以及PME的建筑材料进料比FFF本质上更不稳定，基于尺寸分析和表面粗糙度比较确定的PME打印物体的最终打印质量低于FFF打印部件的打印层均匀性和结构。此外，由于PME较差的打印分辨率和固有的不稳定建筑材料进料，PME打印物体的整体拉伸强度和杨氏模量（分别为49.2±10.7兆帕和1620±375兆帕）低于FFF打印物体（分别为57.7±2.31兆帕和2160±179兆帕）且更不稳定。尽管如此，PME打印方法有望提供一个平台，在该平台上可以快速制作用于3D打印的多种热塑性材料的原型。
