Force Model of Freeform Surface Multi-axis Machining With Fillet End Mill Based on Analytical Contact Analysis

Author(s):  
Minglong Guo ◽  
Zhaocheng Wei ◽  
Shiquan Li ◽  
Minjie Wang ◽  
Hang Gao ◽  
...  

Abstract In the multi-axis machining of freeform surface, compared with ball end mill, the fillet end mill has higher machining efficiency under the same residual height and has been widely used. As the most important physical quantity in machining process, milling force has always been the focus of research. In this paper, the geometry contact between fillet end mill and freeform surface is analyzed by analytical method, and then the milling force prediction model of multi-axis machining is established. Based on differential discretization, the cutter location of multi-axis machining of freeform surface is approximate to multi-axis machining of oblique plane, which simplifies the research object. The inclination angle is defined to describe the relationship among cutter axis, feed and workpiece in cutter coordinate system. The space range of the cutting edge element participating in material cutting is constructed by the swept surface of previous tool path, the to-be machined surface and the feed direction surface, and the in cut cutting edge is determined by judging the cutting edge element one by one. Considering cutter run-out, the element cutting forces on the cylindrical and fillet surfaces of the fillet end mill are derived, and all the element forces within in cut cutting edge are summed by vector to obtain the overall milling force of fillet end mill. Simulation results show that, compared with the solid method, this contact analysis method between cutter and workpiece can take both efficiency and accuracy into account. In the machining experiment, the measured force and predicted force along tool path are consistent in trend and amplitude, which verifies the effectiveness of the milling force prediction model.

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.


2014 ◽  
Vol 800-801 ◽  
pp. 243-248
Author(s):  
Kai Zhao ◽  
Zhan Qiang Liu

When machining the complex parts of aircraft engines, the milling force for the circular contour must be accurately predicted to reduce machining vibration. In this paper, the prediction model of the mean milling force per tooth during machining circular contour is developed. Firstly, the formulas of the entry angle, the exit angle and the equivalent feed per tooth are established through the analysis of circular contour milling process. Then, the equation of the mean milling force per tooth is deduced based on mechanistic force model during the circular contour machining process. Finally, the prediction model of mean milling force per tooth during machining circular contour is developed using MATLAB programming. The relationship between the milling force per tooth and surface curvature radius of the machined workpiece is also analyzed in this paper.


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.


Author(s):  
Juncheng Wang ◽  
Bin Zou ◽  
Mingfang Liu ◽  
Yishang Li ◽  
Hongjian Ding ◽  
...  

Author(s):  
Jun Wang ◽  
Zhigang Wang ◽  
Weidong Zhu ◽  
Yingfeng Ji

This paper describes a method of machining feature recognition from a freeform surface based on the relationship between unique machining patches and critical points on a component’s surface. The method uses Morse theory to extract critical surface points by defining a scalar function on the freeform surface. Features are defined by region growing between the critical points using a tool path generation algorithm. Several examples demonstrate the efficiency of this approach. The recognized machining features can be directly utilized in a variety of downstream computer aided design/computer aided manufacturing (CAM) applications, such as the automated machining process planning.


2012 ◽  
Vol 516 ◽  
pp. 176-180
Author(s):  
Ryo Nishiyama ◽  
Keiichi Nakamoto ◽  
Tohru Ishida ◽  
Yoshimi Takeuchi

This study deals with 5-axis control tool path generation to create microshapes dexterously and efficiently, while maintaining quality. Concerning 5-axis control machining, the use of ball end mills is generally employed. However, this method needs a lot of time to obtain high quality surface. To solve this problem, a side cutting edge of the ball end mill is positively utilized with its parallel to the ruled surface. Therefore, a new CAM system is developed to detect the surface to be machined with the side cutting edge, and to generate collision-free tool paths between the tool and the work piece. The effectiveness of the developed CAM system is experimentally confirmed by creating a tiny Möbius ring.


Author(s):  
Jieqiong Lin ◽  
Chao Wang ◽  
Mingming Lu ◽  
Jiakang Zhou ◽  
Shixin Zhao ◽  
...  

The machining process of SiCp/Al composites is considerably difficult because of the addition of ceramic particles. As an effective machining method, ultrasonic vibration-assisted turning is used to process SiCp/Al composites, which can effectively reduce the cutting force, improve the surface quality, and reduce the tool wear. This study developed a cutting force prediction model for ultrasonic vibration-assisted turning of SiCp/Al composites, which comprehensively considers the instantaneous depth of cut and the instantaneous shear angle. This model divides the cutting force into the chip formation force considering the instantaneous depth of cut, the friction force considering the influence of SiC particles at tool-chip interface, the particle fracture force, and the ultrasonic impact force in the cutting depth direction. By comparing the predicted value of the main cutting force with the experimental values, the results present the same trend, which verifies the feasibility of the cutting force prediction model. In addition, the influence of vibration amplitude, depth of cut, and cutting speed on the main cutting force is analyzed. The systematic cutting experiments show that ultrasonic vibration-assisted turning can significantly reduce the cutting force and improve the machinability of SiCp/Al composites.


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