Process Planning for Hybrid Manufacturing: Ball Nose End Milling and Direct Energy Deposition of Stainless Steel

Abstract

Abstract Hybrid manufacturing can combine additive and machining processing to create parts that would otherwise require two or more machines and can provide many beneficial opportunities in the manufacturing industry. This paper details the creation and application of a generalized process plan for the hybrid manufacturing of AISI 316L stainless steel, using direct energy deposition (DED) and ball-nose end-mill machining; that includes the inspection and measurement of objects created by that hybrid manufacturing process plan. The proposed process plan progresses through the selection of substrate thickness, single-track, multi-track, and multi-layer depositions, then on to machining processing. A manufacturers’ recommended set and range of DED parameters were used to create a designed experiment that aided in the analysis of objects created in each of the DED process planning steps; those objects were then machined in the same enclosure using a set of machining parameters screened from industry recommendations for ball-nose milling of stainless steel, after which measurements were taken for surface roughness, some material characteristics, and for tool deterioration. The results, analyses, and discussions collected herein show that the proposed process plan can provide models for geometrical outputs for each step in the plan, some improvements in substrate stability, surface roughness, tool deterioration, and material porosity due to voids. Current research in hybrid manufacturing does not show generalized process planning influences. The process plan, as demonstrated by the work in this paper will help operators, designers, and researchers in the future by defining a generalized workflow that can be applied to other materials used in the form of hybrid manufacturing that combines DED with machining processes.