Part Consolidation for Additive Manufacturing Demonstrated in the Design of a 3D-Printed Harmonic Drive

Abstract

The goal of this project is to establish a novel design approach for the additive manufacturing of mechanical transmission systems. Our focus is the design and 3D printing of a harmonic drive. Harmonic drives use the elastic dynamics of metals to create an elliptical rotation, which is what conceives the reduction of speed of the outer piece. Additive manufacturing is used to achieve more complex and precise mechanical structures. Components of less complexity will be 3D printed with polymer and commercial parts will be purchased. There is a need for the creation of new plastics manufacturing processes that define and simplify the decision methods involved in the production. With this project, we will establish the process we consider best for plastic additive manufacturing. The decision of which parts are 3D printed or machined affects the harmonic drive’s cost and lead-time; therefore, several alternatives are systematically analyzed. The final bill of materials contains the list of commercial parts and 3D printed parts. When assembled, a functioning harmonic drive is produced. The final harmonic drive is experimentally tested to determine the life of its components when subjected to working loads. The methods used in this research include the part consolidation for the optimization of the system, transcription of 3D models to STL files that can be printed, polymer additive manufacturing and traditional quality control techniques to improve the design. Material models utilized in this project are commercial aluminum parts, 3D printer and plastic, and a low-voltage power motor. The complete set of results will give torque and speed reduction ratios that will be compared to those previously obtained by electronic simulations. This locates us a step ahead in the creation of an optimal process for additive manufacturing.