Algorithmic optimization of process selection for additive-subtractive hybrid manufacturing

Additive and conventional subtractive hybrid manufacturing has emerged to take advantage of the capabilities of both processes. The confluence of several factors poses pros and cons for manufacturers seeking the most efficient process selection for manufacturing complex parts. The primary difficulty lies in making well-informed decisions incorporating additive and subtractive processes. Machine users employ heuristic judgments to make process selections, often relying on time-consuming trial-and-error methods that produce waste. The proposed research aims to develop an algorithm that can automatically determine the most efficient manufacturing strategy, i.e., purely additive, purely subtractive, or hybrid to make a part, integrating subtractive machining, and laser directed energy deposition (DED). The methodology proposed is that given a boundary-representation model of a part, the algorithm sections and splits the geometry into its sub-features based on various splitting methods. The sectioning of geometry into its sub-features is needed to determine which manufacturing process should be used to make that particular sub-feature, utilizing the hybrid capability of the machine. The machinability of the entire model and each sub-feature is automatically determined using the directional vector approach relative to the z-axis of the machine. The algorithm then performs the efficiency analysis on each sub-feature regarding productivity, material cost, and energy cost. It then recommends the most efficient manufacturing process for the entire part geometry. The algorithm also allows users to input efficiency constants to assign weight to parameters. Subsequently, a user-preferred manufacturing process is then suggested as the output. The software is capable to store databases for selective machines and their parameters, which can be overwritten by the user. The software is developed using Microsoft Foundation Classes (MFC) Visual Studio application in C++, incorporating Siemens Parasolid geometric modeling kernel, Hoops3D Visualize, and Exchange application programming interfaces. The research is still in progress. Future work will expand the algorithm to enable automated sectioning. The proposed equations governing productivity, material cost, and energy costs will be validated through experimentation on the DMG Mori Lasertec 65 DED Hybrid machine.