Efficient Tool Path Generation Research Articles

Efficient Toolpath Generation Method for High-Quality and High-Accuracy Machining of Curved Surfaces

Currently, there is no function in commercial CAM systems to generate optimal quality machining for curved surfaces. In computer-aided manufacturing (CAM) systems, the toolpath (cutter location data) is derived as an approximately straight-line segment based on a plane approximation surface instead of a free-form surface from the designed shape. Due to this approximation, machining accuracy and quality are decreased, especially in the region with characteristic lines like in an outer automobile covering part. This paper presents an algorithm procedure for toolpath generation to process complex parts with characteristic curves with high-quality and high-accuracy machining by dividing the surface into different regions, the region where machining accuracy is not required as a plane approximation surface and the remaining region where accuracy is required as free-form surfaces. The proposed method was confirmed by machining experiments that actual machining realized high machining quality and accuracy compared to the conventional CAM system.

Robust and efficient tool path generation for machining low-quality triangular mesh surfaces

This paper presents a new method to generate iso-scallop tool paths for triangular mesh surfaces. With the popularity of 3D scanning techniques, scanning-derived mesh surfaces have seen a significant increase in their application to machining. Quite often, such mesh surfaces exhibit defects such as noises, which differentiate them from the good-quality mesh surfaces previous research work focuses on. To generate tool paths for such low-quality mesh surfaces, the primary challenge lies in robustness against the defects. In this work, a robust tool path generation method is proposed for low-quality mesh surfaces. In addition to robustness, the method is quite efficient, providing the benefit of faster iterations and improved integration between scanning and machining. The fundamental principle of the method is to convert the tool path generation problem to the heat diffusion problem that has robust and efficient algorithms available. The effectiveness of the method will be demonstrated by a series of case studies and comparisons.

Efficient tool path generation for five-axis machining of a difficult machined centrifugal impeller

This article presents an efficient tool path generation method for five-axis machining of a difficult machined centrifugal impeller. Geometry of centrifugal impeller is analyzed, and the inherent low efficiency of the machining of difficult machined centrifugal impeller is obtained. The tool path curves which are calculated by the most common iso-parametric method are shown to testify the waste in machining. The new type machining layers are calculated, and the new machining regions are achieved. The new tool path curves in each new machining region are calculated, and they are sparser and triangular. For the inherent low machining efficiency of difficult machined centrifugal impeller, the machining time can be greatly reduced just by the optimizing tool path generation method in this article. Numerical simulation and a real test impeller are presented as the test of the proposed method.

曲面パラメータに基づいた高精度高効率工具経路生成

曲面パラメータに基づいた高精度高効率工具経路生成

Five-axis tool path and feed rate optimization based on the cutting force–area quotient potential field

Feed rate assignment in five-axis surface machining is constrained by many factors, among which a particularly critical one is the deflection cutting force on the tool: while a larger feed rate increases the machining productivity by shortening the total machining time, it nevertheless inevitably enlarges the deflection cutting force as well, which will cause the tool to be more prone to bending and the machine more prone to vibration, thus adversely degrading the surface finish quality. In this paper, we present a new five-axis tool path generation algorithm that strives to globally maximize feed rate for an arbitrary free-form surface while respecting a given deflection cutting force threshold. The crux of the algorithm is a new concept of the (cutting) force–area quotient function—at any cutter contact point on the surface, the maximal effective material removal rate (with respect to the deflection cutting force threshold) is a continuous function of the feed direction. This function induces a potential field on the surface and based on which an efficient tool path generation algorithm is designed. Preliminary experiments show that substantial reduction in total machining time can often be achieved by the proposed algorithm.

A Surface Parameter-Based Method for Accurate and Efficient Tool Path Generation

Along with the increasing need for multi-axis and multi-tasking machining tools for the machining of complex free surfaces, the importance of CAM applications related to the accuracy of the free surfaces has increased dramatically. The machining accuracy and surface integrity of a product depends not only on the performance of the machining tool itself but also on the tool path generated by CAM. At present, there is a trade off between numerical calculation errors and cost in CAM. There is no calculation method that satisfies both sides. Of particular importance is the fact that the cost increases exponentially with the rank of the free surface. Therefore, this paper proposes a new method of generating tool paths efficiently; it generates tool paths directly from 2-dimensional parametric space by using the parametric surface defined as a polynomial. We confirm that this method can reduce the cost and that the tool path can be generated by means of a simple calculation process, without considering singular points. Moreover, since commercial CAM kernels cannot accommodate to our method, we design and implement a new CAM kernel that can access the parametric surface directly in order to develop this method.

Tool path generation by offsetting curves on polyhedral surfaces based on mesh flattening

Polyhedral surfaces are used as representation model for CAM and process planning purposes because of its simplicity for data exchange and geometric computation. However, there are few tool path planning strategies for such surfaces but isoplanar method. This paper presents a contour offset approach to tool path generation for three-axis ball-end milling of polyhedral surfaces, based on a novel method for offsetting curves on polyhedral surfaces. One of its salient features is to reduce the task of removing complex interfering of offsets from 3D physical surfaces to 2D plane by flattening mesh surfaces and avoid costly 3D Boolean set operations and relatively expensive distance calculation. Moreover, in practical implement, the procedures of calculating offset points and removing interfering loops are merged and carried out simultaneously results in an efficient tool path generation method. Empirical examples illustrate the feasibility of the proposed method.

Contour Offset Approach to Generate Tool Path for Polyhedral Surfaces Machining

Polyhedral surfaces are used as representation model for CAM and process planning purposes because of its simplicity for data exchange and geometric computation. However, there is few tool path planning strategies for such surfaces but the iso-plane method. In this paper, contour parallel path are generated for three-axis ball-end milling. This tool path is based on a novel algorithm for offsetting curves on polyhedral surfaces presented in this paper. It reduces the task of removing complex interfering of offset curve from 3D surface to 2D plane by flattening mesh surface, and avoids costly 3D Boolean set operations and expensive distance calculation. This results in an efficient tool-path generation. Empirical examples illustrate the feasibility the proposed method.

An Adaptive Tool Path Generation for Large Scale Wedge/Aspheric Lens Element Grinding Based on Isophote Interpolation

Large scale wedge/aspheric lens element is a combination of wedge prism and aspheric lens as a single piece component forming a decentred lens, which is primarily manufactured by Computerized Numerical Control (CNC) machining, especially 3-axis CNC grinding. This paper presents an efficient tool path generation approach based on isophote interpolation. The interpolation guarantees that interpolated points always stay on the iso-inclination curve of the parametric surface. This symmetry ensures that the method can improve and automate large scale wedge/aspheric lens element machining for 3-axis CAD/CAM systems. As part of the validation process, the tool paths generated are analyzed and compare with the desired part.

3282 Efficient Tool Path Generation for Five-Axis Controlled Machining by Use of Square End Mill

3282 Efficient Tool Path Generation for Five-Axis Controlled Machining by Use of Square End Mill

Tool path generation and modification for constant cutting forces in direction parallel milling

This paper presents an optimized path generation algorithm for direction parallel milling, which is commonly used in the roughing and finishing stages. First, a geometrically efficient tool path generation algorithm using an intersection points graph is introduced. Second, the generated tool path is modified as an optimized tool path that maintains a constant material removal rate to achieve a constant cutting force and avoid chatter vibration, and the results are verified. Additional tool path segments are appended to the basic tool path through a pixel-based simulation technique. The algorithm is implemented for two-dimensional contiguous end milling operations with flat end mills, and cutting tests are conducted by measuring the spindle current, which reflects the changing machining situations, to verify the performance of the proposed method.

Optimum tool path generation for 2.5D direction-parallel milling with incomplete mesh model

Many mechanical parts are manufactured by milling machines. Hence, geometrically efficient algorithms for tool path generation, along with physical considerations for better machining productivity with guaranteed machining safety, are the most important issues in milling. In this paper, an optimized path generation algorithm for direction-parallel milling, a process commonly used in the roughing stage as well as the finishing stage and based on an incomplete 2-manifold mesh model, namely, an inexact polyhedron widely used in recent commercialized CAM software systems, is presented. First of all, a geometrically efficient tool path generation algorithm using an intersection points-graph is introduced. Although the tool paths obtained from geometric information have been successful in forming desired shapes, physical process concerns such as cutting forces and chatters have seldom been considered. In order to cope with these problems, an optimized tool path that maintains a constant MRR for constant cutting forces and avoidance of chatter vibrations, is introduced, and verified experimental results are presented. Additional tool path segments are appended to the basic tool path by means of a pixel-based simulation technique. The algorithm was implemented for two-dimensional contiguous end milling operations with flat end mills, and cutting tests measured the spindle current, which reflects machining characteristics, to verify the proposed method.

Tool-Path Generation Based on Angle-Based Flattening

Free-form surfaces represented by triangular meshes are widely used in modern product design and manufacture. However, most existing methods are very limited to machining mesh surfaces. In this paper, a new tool-path generation method is presented for machining mesh surfaces by three-axis ball-end milling. First, angle-based flattening, a recently emerging parameterization technique, is used to map triangular meshes from a three-dimensional (3D) physical space to a two-dimensional (2D) parametric plane. Then, the cutter contact points are calculated by continuously offsetting a drive curve. The main advantage of the method is that it reduces the task of tool-path generation from 3D to 2D space. Therefore, the tool-path generation can be analysed and calculated in a plane. This results in an efficient tool-path generation method, without complex geometric calculation such as determining drive plane, surface slicing, and intersection, in a 3D space. Its feasibility and efficiency are demonstrated by several experiments.

황삭 가공을 위한 최적 직선 평행 공구경로 생성

The majority of mechanical parts are manufactured by milling machines. Hence, geometrically efficient algorithms for tool path generation and physical considerations for better machining productivity with guarantee of machining safety are the most important issues in milling tasks. In this paper, an optimized path generation algorithm for direction parallel milling which is commonly used in the roughing stage is presented. First of all, a geometrically efficient tool path generation algorithm using an intersection points-graph is introduced. Although the direction parallel tool path obtained from geometric information have been successful to make desirable shape, it seldom consider physical process concerns like cutting forces and chatters. In order to cope with these problems, an optimized tool path, which maintains constant MRR in order to achieve constant cutting forces and to avoid chatter vibrations at all time, is introduced and the result is verified. Additional tool path segments are appended to the basic tool path by using a pixel based simulation technique. The algorithm has been implemented for two dimensional contiguous end milling operations, and cutting tests are conducted by measuring spindle current, which reflects machining situations, to verify the significance of the proposed method.

Incomplete mesh-based tool path generation for optimum zigzag milling

The majority of mechanical parts are manufactured by milling machines. Hence, geometrically efficient algorithms for tool path generation and physical considerations for better machining productivity with guarantee of machining safety are the most important issues in milling tasks. In this paper, we present an optimized path-generation algorithm for zigzag milling, which is commonly used in the roughing stage as well as in the finishing stage, based on an incomplete two-manifold mesh model, namely, an inexact polyhedron that is widely used in recent commercialized CAM software systems. First of all, a geometrically efficient tool path generation algorithm using an intersection points-graph is introduced. Although the tool path obtained from geometric information has been successful to make a desirable shape, it seldom considers physical process concerns like cutting forces and chatter. In order to cope with these problems, an optimized tool path that maintains constant MRR in order to achieve constant cutting forces and to avoid chatter vibrations at all times is introduced and the result is verified. Additional tool path segments are appended to the basic tool path by using a pixel-based simulation technique. The algorithm was implemented for two-dimensional contiguous end-milling operations with flat end mills and cutting tests were conducted by measuring the spindle current, (which reflect machining situations) to verify the significance of the proposed method.