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This paper presents an enhanced marching cubes algorithm to construct an iso-boundary for in-process geometric modeling for material removal processes. The author first analyzes the tool motion and the geometric properties in material removal processes. The result shows that the in-process geometry is the complement of the tool swept volume from the raw material. The in-process geometry can be determined by continuously updating itself from the swept volume of the tool. This study uses a three-dimensional G-buffer to update the intersection information between the tool swept volume and the in-process geometry: Rather than traditionally searching for all intersection points ranging in a cube, the developed algorithm uses certain specific intersection points that are selected based on the removal geometry, properties to construct the iso-boundary. It avoids the unfavorable ambiguities and holes on constructed boundaries. In addition, the developed algorithm is able to handle multiple intersection points in a cubical edge. This study also discusses material removal volume and tool collision issues. The computer implementation shows that the developed method is superior to the traditional ones in material removal applications. Keywords: marching cubes algorithms, geometric simulation, G-buyer [DOI: 10.1115/1.2716703]

This paper presents a swept envelope approach to determining the optimal tool orientation for five-axis tool-end machining. The swept profile of the cutter is determined based on the tool motion. By analyzing the swept profile against the part geometry', four types of machining errors (local gouge, side gouge, rear gouge, and global collision) are identified. The tool orientation is then corrected to avoid such errors. The cutter's swept envelope is further constructed by integrating the intermediate swept profiles, and can be applied to NC simulation and verification. This paper analyzes the properties of the swept profile of a general cutter in five-axis tool-end machining. The relation of the swept profile, the part geometry, the tool motion, and the machining errors is developed. Therefore, the error sources can be detected early and prevented during tool path planning. The analytical results indicate that the optimal tool orientation occurs when the curvature of the cutter's swept profile matches with the curvature of the local part surface. In addition, the optimal cutting direction generally follows the minimum curvature direction. Computer illustrations and example demonstrations are shown in this paper. The results reveal the developed method can accurately determine the optimal tool orientation and efficiently avoid machining errors for five-axis tool-end machining. [DOI: 10.1115/1.2035698]

Abstract: This paper presents a floor–wall and ceiling (FWC) approach to determining the tool axes for five-axis pocket machining. The FWC method generates tool axes by simply linking the corresponding points between tool location paths on floor and tool axial paths on ceiling. The geometry of the floor, wall, and ceiling of a pocket are first discussed. The construction and manipulations of the tool location paths and the tool axial paths are then addressed. The relationship between the tool axis variation and the manipulations is analyzed such that the generated tool axes are guaranteed to be smooth, optimized, and collision-free. By using the FWC method, the complexity of determining the tool axes can be significantly reduced. Computer illustrations and example demonstrations are shown in this paper. The results reveal that the FWC method can generate much higher quality tool axes than the traditional methods. [Copyright &y& Elsevier]