3D Printed Robot Arm

Abstract

This thesis research was developed with the goal of designing and manufacturing a 3D printed robotic arm entirely in PLA through design iterations. The PLA manufacturing constrain was set due to its ease of replicability. The project was to be realised through abstract design, having no initial base of comparison in links or features, instead, the result of the project was measured through the achieved capabilities in reach, payload, and resistance. The first objective was to through the process identify the best manufacturing parameters for 3D print designs with the intention of achieving superior strength and resistance. They were defined as been layer height 0,16 mm and the honeycomb infill geometry pattern. The second objective was to establish the maximum payload the robot arm would be able to lift at the maximum extension of 363,41 mm while the material is still in its elastic region, meaning no irreversible plastic deformation nor structural damage. Through the SolidWorks® study simulations (static, frequency and buckling), the maximum payload of 4 kg was detected for the structure to stay within the factor of safety of 1,7. The choice of materials was done by analysing the manufacturers’ information on material and strength properties of different types of PLA based filament, them being PLA, Tough PLA, Hyper PLA, and PLA-CF. The material chosen was the Creality Hyper PLA for its superior tensile strength and bending strength. The goal is that through combining the most reliable structural geometrical formation for infill printing, defined by literature review, with the most appropriate filament, would guarantee the optimal manufacturing of the robot’s links resulting in the continuous operation of the robotic arm for an extended period of years, without presenting signs of fatigue or deformation. The third target was to identify through a frequency study simulation, the eigenmodes, their shape and amplitude in the designed arm. The mode 4 with its eigenfrequency of 25,39 Hz, and amplitude of 1,20 mm was found to be the most critical in the analysis, occurring in link 3 and link 4.