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The manufacture of a marine propeller typically requires long lead-time to generate five-axis tool paths. It usually takes several days to generate satisfactory tool paths with a general purpose CAD/CAM system. This paper proposes a novel methodology that generates effective five-axis tool paths for marine propellers. The machining of a propeller is accomplished in three steps: rough cut, semi-finish cut, and finish cut. For generating accurate finish cut tool paths, the proposed system computes check vectors that determine a maximum range of valid tool motion based upon tool size and passage width for each CL (Cutter Location) point along the tool path. Interference-free tool paths can be acquired by positioning the tool inside the two check vectors. The modelling capability for propellers is also of importance because it determines the eventual success or failure of the whole process. An iterative B-spline surface modelling technique is employed to improve the accuracy of the models and to increase the productivity. The proposed system generates interference-free tool paths with superior surface finish and reduces lead-time to manufacture a propeller. The system validation and sample results are given and discussed. [ABSTRACT FROM AUTHOR]

This paper proposes a new tool path generation method for machining impellers with five-axis machines. Using the geometric characteristics of impellers, the proposed method first computes the tool path in the cylindrical coordinates and then converts it into the cartesian coordinates. The proposed method is simpler, more efficient, and requires less user interactions than known methods. Collision avoidance and optimum cutting condition issues are also addressed in this paper. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a new efficient and robust tool-path generation method that employs a curve-based approach for clean-up machining. The clean-up machining discussed in this paper is pencil-cut and fillet-cut for a polyhedral model of the STL form with a ball-end mill. The pencil-cut and fillet-cut paths are obtained from the curve-based scanning tool paths on the xz, yz, and xy planes. The scanning tool path has exact sharp-concave points and bi-contact vectors, both of which are very useful to detect ‘pencil-points’, to trace the pencil-cut path, and to generate the fillet-cut path. In the paper, some illustrative examples are provided, and the characteristics of the proposed method are discussed. [Copyright &y& Elsevier]

This paper presents a new approach to three-axis NC tool path generation for sculptured surfaces. In the proposed curve-based approach, the gouge-free tool paths are generated from a polyhedral model of the STL (stereolithography) format. The polyhedral model is offset by a local-offsetting scheme. Then, the offset elements such as triangular facets, trimmed cylinders, and trimmed spheres are sliced by a series of drive planes. The curve segments on a drive plane are sorted, trimmed and linked, while the concave gouge is removed during the trimming process. The method is implemented on a PC, and some illustrative examples are provided in this paper. The main advantage of the proposed method is that the tool path can be generated from a polyhedral model without any concave and convex gouge, especially on an NC machine that supports NURBS interpolation. Other advantages and disadvantages of the proposed model are also discussed. [Copyright &y& Elsevier]