Design and Fabrication of an Oscillating Tool for Powder Spreading in Metal Additive Manufacturing

Abstract

Powder spreading methods for metal additive manufacturing processes, such as laser powder bed fusion and binder jetting, are intended to produce thin, dense, and uniform powder layers in order for finished parts to have satisfactory material and mechanical properties. The spreading of fine powders is particularly challenging due to their cohesive nature. Previous computational simulations have been performed and show that using a linearly oscillating spreading tool can have favorable results on layer quality. This thesis focuses on the design and implementation of an oscillating spreading tool on a pre-existing testbed. The system dynamics of an object oscillating at an amplitude of 40 microns at frequencies in the range of 9.55 - 955 Hz are modeled and analyzed. Two designs are developed for the mechanism, powered by either a piezoelectric stack or a voice coil linear motor. The machining of parts was qualified for runout and straightness, and the assembly of the piezo mechanism was built onto the testbed. Work remains to complete the system implementation and to test the motion and simulation results. Continued improvements and further work are suggested.