Direct Digital Subtractive Manufacturing of a Functional Assembly Using Voxel-Based Models

Abstract

Direct digital manufacturing (DDM) is the creation of a physical part directly from a computer-aided design (CAD) model with minimal process planning and is typically applied to additive manufacturing (AM) processes to fabricate complex geometry. AM is preferred for DDM because of its minimal user input requirements; as a result, users can focus on exploiting other advantages of AM, such as the creation of intricate mechanisms that require no assembly after fabrication. Such assembly free mechanisms can be created using DDM during a single build process. In contrast, subtractive manufacturing (SM) enables the creation of higher strength parts that do not suffer from the material anisotropy inherent in AM. However, process planning for SM is more difficult than it is for AM due to geometric constraints imposed by the machining process; thus, the application of SM to the fabrication of assembly free mechanisms is challenging. This research describes a voxel-based computer-aided manufacturing (CAM) system that enables direct digital subtractive manufacturing (DDSM) of an assembly free mechanism. Process planning for SM involves voxel-by-voxel removal of material in the same way that an AM process consists of layer-by-layer addition of material. The voxelized CAM system minimizes user input by automatically generating toolpaths based on an analysis of accessible material to remove for a certain clearance in the mechanism's assembled state. The DDSM process is validated and compared to AM using case studies of the manufacture of two assembly free ball-in-socket mechanisms.

Present and Future Impacts of Computer-Aided Design/ Computer-Aided Manufacturing (CAD/CAM)

“…All AM techniques such as direct energy deposition (DED), powder bed fusion (PBF) all make use of CAD designs [17]. 2.2.2 Subtractive manufacturing Lynn et al [19] described voxel-centered CAM systems that enable direct digital subtractive manufacturing of an assembly-free system. Process preparation for subtractive manufacturing (SM) includes voxel-by-voxel elimination of fabric in the same manner as an additive manufacturing process, which comprises layer-by-layer fabric addition.…”

Intensity-Based Registration With Voxel-Based Computer-Aided Manufacturing for Adaptive Machining

“…Future research should employ a hybrid structure for efficiency and practicality. This article examines intensity-based registrations through the context of previous works [8,[12][13][14]32,34] demonstrating the practical application of voxel processing in CAM.…”

“…Popular methods used the field are voxel intensity-based [7]. Although these representations are memory intensive compared with parametric surfaces, research in voxel-based CAM [8][9][10][11][12][13][14] has shown some advantages over classical approaches in five-axis machining. Specifically, voxels begin to be profitable as part complexity increases and collision avoidance becomes difficult.…”

A Review on Significant Role of Additive Manufacturing in Biomedical Applications

“…Forming is a process where a work piece is molded without adding or reducing material [2]. Subtractive manufacturing is a process that involves using tools to remove unwanted material [3]. In additive manufacturing, the process involves adding material to a finished product [4].…”