Towards a General Method for Constructing Manufacturability Design Rules for an Additive Manufacturing Process

Abstract

Additive manufacturing (AM) presents a unique set of manufacturability constraints, among the most important of which are the smallest producible feature size and the maximum overhang angle before support structures are required. In this work, an approach is presented which includes both a parameterization strategy for small features, and a subsequent iterative experiment for realizing minimum feature size design rules as functions of feature shape and orientation. This approach was designed to be applicable to a wide variety of AM processes, and was applied to an example machine in the material extrusion AM process category for demonstration purposes. This case study involved a thorough experimental evaluation to explore the tradeoffs between the number of oriented shapes evaluated and the predictive quality of the resulting design rules, and the results produced found that minimum feature size can vary by as much as 10x over the set of considered oriented shapes for the AM system studied. Compared to existing design rules in the literature, using the proposed approach made it possible to increase the design space for the AM system considered by providing lower minimum feature sizes when possible, by incorporating more accurate overhang angle constraints into the minimum feature size definition, and by detecting un-manufacturable features that existing design rules would have incorrectly allowed.