A method and software prototype to support on-line planning on CNC machines

Process planning for parts made on CNC machines is usually performed in sequence and carried out without feeding back information about the fabrication process to the planning stage. Shifting planning capabilities to the machine level enables consideration of direct machine feedback. In this paper a method for feature decomposition and tool path planning for pocket milling on a 3 axis milling machine is presented. Based on standard computerized numerical control (CNC) technology, G-code is transferred to the fabrication machine whereat adaptation of processing parameters can take place within a feature. In order to enable a feedback loop from the processing to the planning stage, subfeature elements are defined. Interrelations between subsequent elements are identified and standardized with regard to the manufacturing needs to realize fully machined features. For each element a tool path is generated and translated into valid G-code. After fabrication of each subfeature element processing parameters can be improved. The presented method is implemented in a prototype software tool based on an open source CAD/CAM/CAE kernel and extends an existing open source CAM software framework.Copyright © 2008 by ASME