Investigations on microwave-assisted welding of MEX additive manufactured parts to overcome the bed size limitation

Additive Manufacturing (colloquially: 3D printing) is ready to emerge from its niche status and become a feasible mainstream technology due to its increasing number of industrial applications. However, the restricted size of the prints, resulting from the printer's limited bed size is an aspect hindering the acceptance of this technology. Splitting the CAD model and joining them with some viable technique can be an evocative solution to this challenge. This article investigates the welding of MEX-AM parts made from frequently chosen thermoplastics (Acrylonitrile Butadiene Styrene/Polylactic Acid) ABS/PLA with the assistance of electromagnetic microwave radiations, employing inexpensive Fe2O3 as the absorbent material. The foremost objective of the investigation was to counterbalance the dimension limits of MEX 3D printers by microwave welding and simultaneously optimize the parameters involved in the process. Critical parameters including microwave power level, absorbent quantity, welding pressure, infill percentage and material combination were optimized via (Design of Experiments/Analysis of Variance) DOE/ANOVA statistical tools. The outcome resulted in the joint efficiency reaching upto 99.53%. ABS being amorphous, responded well to the microwaves displaying better shear strength and ductility compared to PLA. Further, it was observed that a temperature of 120 to 165 °C with lead-times of 5 to 8 min was approximately required for the successful welds to happen. The predicted and validated results revealed that for maximum joint efficiency, the parameters to be set should be 1000 W, 0.2 g absorbent, 400 g dead weight and 35% infill percentage with ABS/ABS as the printing material. The results when applied to repair a drone body, weld a (Unmanned Aerial Vehicle) UAV wingspan, helmet sections as well as pump flanges displayed good structural strength and integrity. The proposed technique displayed enormous potential as it could easily be reproduced even on a household microwave oven obtaining complex 3D structures and raising the adequacy of smaller bed 3D printers.