Time-Efficient Trochoidal Tool Path Generation for Milling Arbitrary Curved Slots

Author(s):  
Ke Xu ◽  
Baohai Wu ◽  
Zhaoyu Li ◽  
Kai Tang

Trochoidal (TR) tool paths have been a popular means in high-speed machining for slot cutting, owing to its unique way of cyclically advancing the tool to avoid the situation of a full tool engagement angle suffered by the conventional type of slot cutting. However, advantageous in lowering the tool engagement angle, they sacrifice in machining efficiency—to limit the tool engagement angle, the step distance has to be carefully controlled, thus resulting in a much longer total machining time. Toward the objective of improving the machining efficiency, in this paper, we propose a new type of TR tool path for milling an arbitrary curved slot. For our new type of TR tool path, within each TR cycle, rather than moving circularly, the tool moves in a particular way such that the material removal rate is maximized while the given maximum engagement angle is fully respected. While this type of TR tool path works perfectly only for circular slots (including straight ones), by means of an adaptive decomposition and then a novel iso-arc-length mapping scheme, it is successfully applied to any general arbitrarily curved slot. Our experiments have confirmed that, when compared with the conventional TR tool paths, the proposed new type of TR tool path is able to significantly reduce the total machining time by as much as 25%, without sacrificing the tool wear.

2019 ◽  
Vol 18 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Mochammad Chaeron ◽  
Budi Saputro Wahyuaji ◽  
Apriani Soepardi

The machining strategy is one of the parameters which practically influences the time of the different manufacturing geometric forms. The machining time directly relates to the machining efficiency of the tool paths. In area milling machining, there are two main types of tool path strategies: a direction-parallel milling and contour-parallel milling. Then direction-parallel milling is simple compared with a contour-parallel strategy. This paper proposes a new model of the direction-parallel machining strategy for triangular pockets to reduce the tool path length. The authors develop an analytical model by appending additional the tool path segments to the basis tool path for cutting un-machined area or scallops, which remained along the boundary. To validate its results, the researchers have compared them to the existing model found in the literature. For illustrating the computation of this model, the study includes two numerical examples. The results show that the proposed analytic direction-parallel model can reduce the total length of machining. Thus, it can take a shorter time for milling machining.


2012 ◽  
Vol 542-543 ◽  
pp. 1167-1171
Author(s):  
Chun Wang ◽  
Sheng Lin ◽  
Quan Hai Peng

Tool radius compensation is necessary to CNC machining. However, B tool radius compensation leads to work piece burning at the sharp corner of convex contour because of the long time contacts between the work piece and tool, and C tool radius compensation frequently changes machining feed rate for its broken line tool path. This paper presents a novel tool radius compensation method suitable for high speed machining of convex contour, which have the advantages of both B and C tool radius compensation. It uses compound transition with line and arc between the adjacent blocks of CNC program. The offset tool paths of the adjacent blocks extend a small line segment respectively along their tangent direction, then insert an arc between the end points of the two extended line segments. The results of simulation and experiments show that the machining quality of the sharp corner of convex contour is improved and the machining time is shorter than C tool radius compensation.


2011 ◽  
Vol 314-316 ◽  
pp. 1734-1739
Author(s):  
Kai Zhu Li ◽  
Shi Xiong Wu

In order to decrease the radial amout of cutting depth in high speed milling,optimized arc transition has been proposed in corner milling and the circular trochoid model has been used to remove the residual. Mathematical relationship based on radial depth of cutting constrain among tool radius, trochoid radius and tool step length in circular trochoid model have been analyzed .Based on the goal to limiting the radial cutting depth, appropriate parameters have been computed for higher machining quality. To verify the effectiveness of the proposed method, a compared test has been conducted. Experiment shows that optimized tool paths cause a slight increase in machining time but obtain weaker processing vibration and superior machining precision.


2011 ◽  
Vol 223 ◽  
pp. 691-700 ◽  
Author(s):  
Xavier Beudaert ◽  
Pierre Yves Pechard ◽  
Christophe Tournier

In the context of 5-axis flank milling, the machining of non-developable ruled surfaces may lead to complex tool paths to minimize undercut and overcut. The curvature characteristics of these tool paths generate slowdowns affecting the machining time and the quality of the machined surface. The tool path has to be as smooth as possible while respecting the maximum allowed tolerance. In this paper, an iterative approach is proposed to smooth an initial tool path. An indicator of the maximum feedrate is computed using the kinematical constraints of the considered machine tool, especially the maximum velocity, acceleration and jerk. Then, joint coordinates of the tool path are locally smoothed in order to raise the effective feedrate in the area of interest. Machining simulation based on a N-buffer algorithm is used to control undercut and overcut. This method has been tested in flank milling of an impeller and can be applied in 3 to 5-axis machining.


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.


2014 ◽  
Vol 635-637 ◽  
pp. 497-501
Author(s):  
Li Min ◽  
Biao Bai ◽  
Yu Hou Wu ◽  
De Hong Zhao

In this paper, we have presented a method to generate efficient NC tool paths based on the surface subdivision. The main objective is to achieve high efficiency in the machining of sculptured surface. The NC machining efficiency can be improved by segmenting the whole surface into distinct areas according to the characters of sculptured surface and by using different size mills and different tool path planning methods to machine the areas. The iso-parametric method and large mills are used in the curvature changing little areas. While the iso-scallop method and small mills are used in curvatures changing large areas. This can make full use of tool path generation methods and mills, which improve the machining efficiency of sculpture effectively.


2012 ◽  
Vol 591-593 ◽  
pp. 468-471
Author(s):  
Yong Xia Liu ◽  
Ru Shu Peng ◽  
Qiang Cheng

The advantages and current problems for the application of high-speed machining technology in mold manufacturing are discussed. The requirements of mold high-speed machining for tool paths are summarized. Using the software of Cimatron E7.0,the NC program of the outer mold for a car engine’s V8 intake manifold is analyzed and optimized designed. Programming technology and optional of cutters have been introduced in detail. In the high speed milling stages, using the new cutters, the hardened mold can be machined to reach the required size, shape and surface roughness, and the machining time is reduced greatly. The method of making high speed NC template based on the software Cimatron E7.0. is introduced. Using this method, the maching efficiency is improved greatly, and the mold’ s surface quality better.


Author(s):  
Der-Min Tsay ◽  
Hsin-Pao Chen ◽  
Sa´ndor Vajna ◽  
Michael Schabacker

To increase productivity of marine propellers by raising machining efficiency, this paper presents the zigzag/spiral tool paths generation algorithm based on the arc base curve approach for three-axis machining of curved surfaces of propellers. By considering the shapes of selected cutters with different types of tool paths generated by the proposed procedure, machining efficiency can be calculated and simulated. To verify the accuracy and effectiveness of the developed approach, numerical and experimental results of machining of propeller surfaces are compared. It was proved that the machining time can be cut down up to 19% by using zigzag tool paths with a toroidal cutter. In addition, the machining knowledge revealed here can be accumulated for benefit evaluation in the manufacturing process with existing CAD/CAM systems. From the cost model, design, and process views, the overall cost savings after 5 years are investigated, and the expected benefit yield is about 45%.


Author(s):  
Xiaohong Zhu ◽  
Richard F. Riesenfeld

Abstract Today’s part geometries are becoming ever more complex and require more accurate tool path to manufacture. Machining process efficiency is also a major consideration for designers as well as manufacturing engineers. Although the current advanced CAD/CAM systems have greatly improved the efficiency and accuracy of machining with the introduction of Numerically–Controlled machining, excessive material may still be left on the finished part due to machining constraints, including the inaccessibility of the designed part geometry with respect the cutter, machine motion constraints like ramp angles, specific cutting patterns, etc. Polishing operations such as grinding and hand finishing are quite time consuming and expensive, and may damage the surface of the part or introduce inaccuracies because of human errors. While most of the existing machining approaches attempt to reduce such excessive restmaterials by modifying NC tool paths, none of them is satisfactory. They can be time–consuming, error prone, computationally intensive, too complicated to implement, and limited to certain problem domains. A compensating cleanup tool path will be developed in this research to automatically remove these excessive material from the finish part. This method greatly reduces the burden of hand finishing and polishing, and also reduces the error and complexities introduced in manually generating cleanup tool paths in the shop floor. More important, the tool path generated by this method will reduce the machining time, and increase tool life compared with optimized tool path which left no excessive material behind.


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.


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