Development of a Large Format Additive Manufacturing System Based on an Off-The-Self Pellet Extruder
Abstract
Large Format Additive Manufacturing (LFAM), or Big Area Additive Manufacturing (BAAM), was introduced to resolve the limitations of the low deposition rate, low scalability, and therefore long print times, of traditional 3D printing methods when applied to the manufacturing of large structures and tooling. LFAM can be used to overcome the high conventional tooling costs of large structures. However, even with robotic setups, LFAM still mainly relies on quasi-planar, 2.5D printing strategies. This fails to reap the advantages of multi-axis printing, such as improved adhesion, reduced support material use, and the ability to create complex curved surfaces. In this research, a KUKA robotic manipulator capable of motion with 6 degrees of freedom is used as a base to develop a pellet-fed, multi-axis, large-format 3D printer. Two configurations of the printer were assessed: initially, a setup where a bed is mounted to a KUKA KR10 R1100 flange, and where the nozzle remains stationary. Later, the system was transitioned to a large robotic environment, integrating a KUKA KR 120 R2700 robot and KL1500/3 T linear rail. In the second configuration, the extruder is attached to the KUKA end effector, and the bed is stationary. This included the utilization of the 10 m rail, enabling the printing of significantly larger parts. To evaluate the comprehensiveness of the LFAM system utilized in this study, experiments were conducted with various parameters to identify the best printing parameters. The LFAM technology developed in this research was experimentally verified to obtain process parameters for the consumer thermoplastic polymers, using PLA as a printing material. The aim is to demonstrate the potential of LFAM through the printing of a mold for manufacturing a composite nosecone. A tool for nosecone was designed for this purpose, and robotics simulation was conducted accordingly. The goal for the additively manufactured tool is to survive the hand layup and autoclave curing processing. To illustrate LFAM’s advancements, several large parts were printed at a faster rate than conventional printers, with the long-term goal of achieving continuous fiber LFAM. The lessons learned from printing large-scale parts are reviewed and summarized, and recommendations for the use of multi-axis LFAM are made.