Efficient Method for Tool Path Generation Based on Region Intersection for Complex Mesh Surface Machining

2013 ◽  
Vol 774-776 ◽  
pp. 1438-1441
Author(s):  
Xiao Bing Chen ◽  
Kun Yu

The machining efficiency of conventional section plane method is low for complex mesh surface machining. An efficient method for tool path generation based on region intersection is proposed. The mesh surface is first divided into a series of intersection regions, then vertex curvatures in perpendicular directions of tool paths are estimated by local fitting method, and variable tool path intervals are computed according to the curvatures, scallop height and cutter radius, finally redundant cutter location points are removed according to machining precision. Experiment results indicate that tool paths generated by proposed method are avail to promote machining efficiency of complex mesh surface machining.

2004 ◽  
Vol 126 (3) ◽  
pp. 515-523 ◽  
Author(s):  
Zezhong C. Chen ◽  
Geoffrey W. Vickers ◽  
Zuomin Dong

Three-axis CNC milling is often used to machine sculptured parts. Due to the complex surface shape of these parts, well-planned tool paths can significantly increase the machining efficiency. In this work a new principle of CNC tool path planning for 3-axis sculptured surface machining is proposed. Generic formula to calculate the steepest tangent direction of a sculptured surface is derived, and the algorithm of the steepest-ascending tool path generation is introduced. A single steepest-ascending tool path has been verified to be more efficient than a single tool path of any other type. The relationship between machining efficiency and three key variables, tool feed direction, cutter shape, and surface shape, is revealed. The newly introduced principle is used in planning tool paths of a sculptured surface to demonstrate the advantages of the steepest-ascending tool paths. This new tool path scheme is further integrated into the more advanced steepest-directed and iso-cusped (SDIC) tool path generation technique. Applications of the new tool path principle and the SDIC tool paths to the machining of sculptured parts are demonstrated.


Author(s):  
Peter Jang ◽  
James A. Stori

This paper presents a new offsetting approach for tool path generation in three-axis sculptured surface machining. The approach generates tool paths with scallop, curvature, and force characteristics which make them suitable for high speed machining. An ellipse in the parametric space is used to approximate the intersection between the ball-end mill and the scallop surface for any cutter contact point on the surface. The envelope formed by these swept ellipses of varying dimension and orientation creates a constant scallop curve which is used to generate offset paths. The offset is developed incrementally, utilizing post-processing techniques to eliminate high-curvature regions in the trajectory. The offsetting approach can generate continuous spiraling trajectories which offer the benefit of minimal tool retractions. Results are shown for spiraling paths generated from both convex and non-convex boundaries.


Author(s):  
Jinting Xu ◽  
Yukun Ji ◽  
Yuwen Sun ◽  
Yuan-Shin Lee

This paper presents a new spiral smoothing method to generate smooth curved tool paths directly on mesh surfaces. Spiral tool paths are preferable for computer numerical control (CNC) milling, especially for high-speed machining. At present, most spiral tool path generation methods aim mainly for pocketing, and a few methods for machining complex surface also suffer from some inherent problems, such as selection of projecting direction, preprocessing of complex offset contours, easily affected by the mesh or mesh deformation. To address the limitations, a new spiral tool path method is proposed, in which the radial curves play a key role as the guiding curves for spiral tool path generation. The radial curve is defined as one on the mesh surface that connects smoothly one point on the mesh surface and its boundary. To reduce the complexity of constructing the radial curves directly on the mesh surface, the mesh surface is first mapped onto a circular region. In this region, the radial lines, starting from the center, are planned and then mapped inversely onto the mesh surface, thereby forming the desired radial curves. By traversing these radial curves using the proposed linear interpolation method, a polyline spiral is generated, and then, the unfavorable overcuts and undercuts are identified and eliminated by supplementing additional spiral points. Spline-based technique of rounding the corners is also discussed to smooth the polyline spiral, thereby obtaining a smooth continuous spiral tool path. This method is able to not only greatly simplify the construction of radial curves and spiral tool path but also to have the ability of processing and smoothing complex surfaces. Experimental results are presented to validate the proposed method.


Author(s):  
Zezhong C. Chen ◽  
Zuomin Dong ◽  
Geoffrey W. Vickers

Abstract Three-axis CNC milling is often used in sculptured parts machining. Due to the complex shape of the part surfaces, optimal tool path planning can significantly improve machining efficiency. In this work the mechanism of 3-axis CNC machining is examined. The generic formulae of steepest direction of sculptured surface are derived. A mathematical proof of the highest machining efficiency of steepest-directed tool path is provided. The most efficient local scheme, steepest-directed tool path in tool path planning, is proposed. This scheme serves as a theoretical base for applying steepest-directed tool path in tool path generation algorithms for 3-axis CNC machining. The tool path has been used to develop the steepest-directed and iso-cusped (SDIC) tool path generation algorithm. An example of SDIC tool paths of a half-cylinder part illustrates the application of steepest-directed tool path.


2021 ◽  
Author(s):  
Tianji Xing ◽  
Xuesen Zhao ◽  
Zhipeng Cui ◽  
Rongkai Tan ◽  
Tao Sun

Abstract The improvement of ultra-precision machining technology has significantly boosted the demand for the surface quality and surface accuracy of the workpieces to be machined. However, the geometric shapes of workpiece surfaces cannot be adequately manufactured with simple plane, cylindrical, or spherical surfaces because of their different applications in various fields. In this research, a method was proposed to generate tool paths for the machining of complex spherical surfaces based on an ultra-precise five-axis turning and milling machine with a C-Y-Z-X-B structure. Through the proposed tool path generation method, ultra-precise complex spherical surface machining was achieved. First, the complex spherical surface model was modeled and calculated, and then it was combined with the designed model to generate the tool path. Then the tool paths were generated with a numerically controlled (NC) program. Based on an ultra-precision three-coordinate measuring instrument and a white light interferometer, the machining accuracy of a workpiece surface was characterized, and t[1]he effectiveness of the provided tool path generation method was verified. The surface roughness of the machined workpiece was less than 90 nm. Furthermore, the surface roughness within the spherical region appeared to be less than 30 nm. The presented tool path generation method in this research produced ultra-precision spherical complex surfaces. The method could be applied to complex spherical surfaces with other characteristics.


Author(s):  
David Manuel Ochoa González ◽  
Joao Carlos Espindola Ferreira

Traditional (direction-parallel and contour-parallel) and non-traditional (trochoidal) tool paths are generated by specialized geometric algorithms based on the pocket shape and various parameters. However, the tool paths generated with those methods do not usually consider the required machining power. In this work, a method for generating power-aware tool paths is presented, which uses the power consumption estimation for the calculation of the tool path. A virtual milling system was developed to integrate with the tool path generation algorithm in order to obtain tool paths with precise power requirement control. The virtual milling system and the tests used to calibrate it are described within this article, as well as the proposed tool path generation algorithm. Results from machining a test pocket are presented, including the real and the estimated power requirements. Those results were compared with a contour-parallel tool path strategy, which has a shorter machining time but has higher in-process power consumption.


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