Parameter Optimization for the 3D Print of Thermo-Plastic Pellets with an Industrial Robot

Abstract

Since the last decade, the industry of 3D printing is sharply on the rise. A new trend in the manufacturing of polymers deals with the production of upscaled products that exceed an object size of one cubic meter. This trend has still some challenges to overcome that aim to reduce the costs and the process time in order to enable a more economical production. A method called Fused Granular Fabrication (FGF) uses thermoplastic pellets as a working material. FGF faces the challenges of upscaled 3D printing. Plastic pellets come to a friction of the cost of filament rolls for typical 3D printing application. Furthermore, they offer a greater variety of materials and can be refilled constantly during the printing process, which guarantees a production of almost unlimited big 3D prints. This paper deals with an industrial robot application of the UAS Technikum Wien that is equipped with a simple pellet extruder. The process parameters for good 3D prints were evaluated in a series of tests. All the tests were performed with Ingeo 4034D PLA pellets. A developed cooling system could speed up the process time by 17% for qualitative 3D prints. This work shows the potential of the FGF method and focuses on the build of an upscaled vase with a height of one meter. It was found out that the system still has an insufficient print speed for larger plastic objects, because of the slow feed rate of the used pellet extruder. As a result, a new research started for an alternative pellet extruder. Some of the potential extruders were good substitutes to produce upscaled 3D prints but they come to a high cost. As a self-made solution a new concept for a pellet extruder was designed. The introduced concept should achieve a material flowrate above 2 kg/h, to enable the 3D print of upscaled plastic products within a single day. As industrial robots are already an essential part of our modern industry 4.0, this technology allows it to easily produce individual products with existing systems. The designed pellet extruder can be mounted and exchanged smoothly to make the modern production more efficient.