ORIGINAL ARTICLE Gouge-free voxel-based machining for parallel processors Joshua Tarbutton & Thomas R. Kurfess & Tommy Tucker & Dmytryi Konobrytskyi Received: 16 April 2013 / Accepted: 19 June 2013 # Springer-Verlag London 2013 Abstract Manufacturers produce complex parts by utilizing computer-aided manufacturing (CAM) software to generate tool paths for a machine tool to follow. CAM systems tradi- tionally rely on parametric surface representations of the parts and complex algorithms to produce the tool paths. This paper presents a new path generation framework that is based on parallel algorithms and hardware that utilizes voxel mod- els. The use of new parallel algorithms allows rapid calcu- lations of tool paths automatically from the voxel model. The core components of this framework are a method of gener- ating digital voxel models from tessellated surface models, a method to obtain digital surface information by a parallel ray-casting approach, and a new approach to calculate gouge-free tool paths in parallel from surface information and generalized cutting geometry. The performance of uti- lizing digital models within this framework is then discussed with respect to timing and actual cutting results. Keywords CNC path planning . Machining . Parallel processing 1 Introduction Two significant technological advances are responsible for the current level of machining productivity. The first is the mathematical ability to represent complex part surfaces with parametric surfaces. The second is the creation of computer numerical control (CNC) machine tools that can follow discrete tool points generated based on these parametric surfaces. The link between the parametric part surface and the actual tool path is computer-aided manufacturing (CAM) software. CAM software generates tool paths by calculating tool points from the underlying parametric part surface and user inputs. Although the process of generating tool paths has advanced considerably, it remains time consuming, cost- ly, unique to the software package used, and often sub- optimal. The current CAM software relies heavily on the user. Process engineers make a number of fixed decisions when generating a tool path with CAM software. They select tool geometry, depth of cut, feed rate, spindle speed, and path template. It is often difficult to make these decisions consid- ering the infinite range of possibilities, and this process can take a considerable amount of time for each part. After these fixed decisions are made, the path is post-processed to pro- duce a CNC code (G-code) for the machine tool. This time- consuming process repeats for any small changes to the part. In addition, due to demanding production schedules, this process is rarely optimized. The inherent input–output char- acteristics of tool path generation would require generation of hundreds to thousands of paths with different input param- eters in order to optimize the resulting tool path. Creating optimal tool paths is typically not practical with the current linear workflow of path generation. In practice, the tool path that works is selected, and the potential productivity and cost savings are usually never realized. The disparity between the information available for process engineers to utilize and the information that is actually used is J. Tarbutton (*) Mechanical Engineering Department, University of South Carolina, 300 Main Street, Columbia, SC, USA e-mail: jat@sc.edu T. R. Kurfess George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 801 Ferst Drive, Atlanta, GA, USA T. Tucker Tucker Innovations, Inc, Waxhaw, NC, USA D. Konobrytskyi Department of Mechanical Engineering, Clemson University, Clemson, SC, USA Int J Adv Manuf Technol DOI 10.1007/s00170-013-5148-x