Generation of Five-Axis Cutter Paths for a Ball-End Cutter With Global Interference Checking

Author(s):  
Der Min Tsay ◽  
Wei Feng Yan

A simple, yet useful procedure is developed to generate tool paths with global interference checking for five-axis machining of turbomachinery components with complex geometries. Based on the projected distance between the surface data and the cutter-axis of a cylindrical ball-end mill, interference between the surface of a workpiece and the cutter can be detected. Given the cutter contact points of the surface and the cutter’s size, it can produce the cutter location data without incurring interference through relatively rotating and tilting the workpiece. Applications of the developed approach to five-axis machining of centrifugal compressor impellers with thirteen and fifteen blades are illustrated to demonstrate the usefulness and reliability of the procedure.

1999 ◽  
Vol 123 (1) ◽  
pp. 50-56 ◽  
Author(s):  
D. M. Tsay ◽  
W. F. Yan ◽  
H. C. Ho

A simple, yet useful algorithm is developed to generate tool paths with global interference checking for five-axis point milling of turbomachinery components. Based on the projected distance between the surface data and the cutter-axis of a cylindrical ball-end mill, interference between the surface of a workpiece and the cutter can be detected. Given the cutter contact points of the surface and the cutter’s size, it can produce the cutter location data without incurring interference through relatively rotating and tilting the workpiece. Applications of the developed procedure to five-axis machining of centrifugal compressor impellers with 13 and 15 blades are illustrated to demonstrate the usefulness and reliability of the approach.


Author(s):  
Tomonobu Suzuki ◽  
Koichi Morishige

Abstract This study aimed to improve the efficiency of free-form surface machining by using a five-axis controlled machine tool and a barrel tool. The barrel tool has cutting edges, with curvature smaller than the radius, increasing the pick feed width compared with a conventional ball end mill of the same tool radius. As a result, the machining efficiency can be improved; however, the cost of the barrel tool is high and difficult to reground. In this study, a method to obtain the cutting points that make the cusp height below the target value is proposed. Moreover, a method to improve the tool life by continuously and uniformly changing the contact point on the cutting edge is proposed. The usefulness of the developed method is confirmed through machining simulations.


2021 ◽  
Vol 143 (9) ◽  
Author(s):  
Minglong Guo ◽  
Zhaocheng Wei ◽  
Minjie Wang ◽  
Jia Wang ◽  
Shengxian Liu

Abstract The core parts with the characteristic of freeform surface are widely used in the major equipment of various fields. Cutting force is the most important physical quantity in the five-axis CNC machining process of core parts. Not only in micro-milling, but also in macro-milling, there is also an obvious size effect, especially in medium- and high-speed milling, which is frequently ignored. In this paper, the milling force prediction model for five-axis machining of a freeform surface with a ball-end mill considering the mesoscopic size effect is established. Based on the characteristics of cutting thickness in macro-milling, a new dislocation density correction form is proposed, and a new experiment is designed to identify the dislocation density correction coefficient. Therefore, the shear stress calculated in this paper not only reflects the cutting dynamic mechanical characteristics but also considers the mesoscopic size effect. A linear function is proposed to describe the relationship between friction coefficient and cutting speed, cutter rake angle, and cutting thickness. Considering cutter run-out, the micro-element cutting force in the shear zone and plough zone are analyzed. The cutting geometry contact between the freeform surface and the ball-end mill is analyzed analytically by the space limitation method. Finally, the total milling force is obtained by summing all the force vectors of cutting edge micro-elements within the in-cut cutting edge. In the five-axis machining experiment of freeform surface, the theoretically predicted results of milling forces are in good agreement with the measured results in trend and amplitude.


Author(s):  
Tyler J. Grimm ◽  
Laine Mears

Abstract Machining of complex geometries is conventionally accomplished through the use of a ball-end mill and a helical toolpath which follows along the contours of the geometry at incremental depths. While effective for the majority of geometries, this method produces scallops which result from the ball-end mill radius and the step size of the toolpath. The size of these scallops, which degrades the surface finish, can be minimized by utilizing a relatively small step size. However, this results in increased machining time. A novel method of scallop removal is simulated and experimentally tested herein on 6061-T6511 aluminum. This method applies a friction stir processing effect to the workpiece by rotating a ball-end mill tool in reverse over the surface of the material subsequent to ball-end mill cutting passes. Additionally, the path constructed for scallop removal was a self-intersecting epicycloid which plastically deforms the scallops in order to reduce the surface roughness and impart favorable compressive surface stress. In this study, the surface variability produced from this process is reported for several different tool paths, determined experimentally and through simulation. Future studies will investigate the microstructural effects of this process, as well as the resulting microhardness and residual stress profile.


Author(s):  
Liping Wang ◽  
Weitao Li ◽  
Hao Si ◽  
Xing Yuan ◽  
Yuzhe Liu

Geometric deviation, defined as the distance between the designed surface and the machined surface, is an important component of machining errors in five-axis flank milling of the S-shaped test piece. Since the interpolated toolpath in practical machining process is the approximation of the theoretical toolpath, the geometric deviation caused by the interpolated toolpath appears. To overcome this problem, a novel geometric deviation reduction method is suggested in this study. First, the features of the S-shaped test piece are analyzed. Second, the theoretical toolpath is generated according to the designed surface and the cutter location data is obtained by discretizing the theoretical toolpath. The linear interpolation of the cutter location data is carried out to obtain the interpolated toolpath. Then, the geometric deviation is modeled by calculating the Hausdorff distance between the tool axis trajectory surface based on the interpolated toolpath and the offset surface of the designed surface. Finally, the geometric deviation is reduced by optimizing the cutter location data without inserting more cutter location points. The machining experiment is conducted to verify the effectiveness of the proposed method. The experimental results agree with the simulation results, and both of them indicate the geometric deviation on the machined surface reduces after optimization.


2013 ◽  
Vol 364 ◽  
pp. 386-390
Author(s):  
Chun Hui Yin ◽  
Huai Jing Jing ◽  
Nuo Di Huang ◽  
Fei Ren

Postprocess capable of converting the cutter location data to machine control data is an important interface between the NC programming design and manufacture.Due to the fact that current research on multi-axis postprocess methods mostly deals with machine tool configurations whose linear and rotational movements are orthogonal, an efficient postprocess algorithm for the five-axis machine with a tilting head is presented in this paper.DMU 80P which is a five-axis machine with a tilting head is selected as an example.Its mechanism model is proposed in this paper according to the mechanism theory.The kinematics model is established using coordinate transformation,and the solution of this model is discussed.Based on these,a window-based post-processor with multi-choice function was developed by VS2010 language.Through the verification by the commercial solid cutting software VERICUT,the feasibility of the algorithm proposed is demonstrated.At last,a real impeller cutting experiment has been conducted and the result further verifies the correctness of the algorithm.


2011 ◽  
Vol 189-193 ◽  
pp. 801-804 ◽  
Author(s):  
Yu Xia Zhao ◽  
Jie Jian Di ◽  
De Wen Gao

An impeller is the core of aviation engine components, the processing quality has a decisive impact on the performance of the engine. An impeller is also one of the most important basic components of centrifugal compressor. When a three-axis CNC machining centre is used for producing an impeller, great difficulties, i.e. collisions between the cutting tool and the impeller, can occur. As the surface is normally twisted in design to achieve the required performance, it can cause overcut and collision problems during machining. To solve these problems, an integrated five-axis machining approach for a centrifugal impeller by combining related machining technologies is developed. As a result, Cutter Location data based on the geometry model of blade and hub of the impeller are generated. Finally, the Cutter Location data is verified through software simulation. The results prove that the machining methodology adopted is useful and efficient.


2012 ◽  
Vol 622-623 ◽  
pp. 525-530
Author(s):  
Tran Duc Tang

This paper presents a postprocessor for five-axis milling machine that capable of converting CL (cutter location) data to machine control data (NC program). The proposed postprocessor method is based on inverse kinematics transformation and postprocessor module is programmed in Visual Basic language. The Deckel Maho DMU 50 eVoluion five-axis machine with two rotary axes (B and C) on the table is modeled and verified in software VERICUT® to validate the NC data generated by proposed postprocessor.


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