Simulation for Cutting Force and Temperature in High-Speed Milling of TB6 Titanium Alloy Daoxia Wu 1a, Changfeng Yao 1b, Dinghua Zhang 1c, Wei Zuo 1d

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1 Applied Mechanics and Materials Online: ISSN: , Vol. 415, pp doi:1.428/ 213 rans ech Publications, Switzerland Simulation for Cutting Force and emperature in High-Speed Milling of B6 itanium Alloy Daoxia Wu 1a, Changfeng Yao 1b, Dinghua Zhang 1c, Wei Zuo 1d 1 he Key Laboratory of Contemporary Design and Integrated Manufacturing echnology, Ministry of Education, Northwestern Polytechnical University, Box 552, Xi an, Shaanxi 772, P. R. China. a wudaoxia877@163.com b chfyao@nwpu.edu.cn c dhzhang@nwpu.edu.cn d @qq.com Keywords: B6 titanium alloy, high-speed milling, milling force, milling temperature Abstract: High-speed milling of titanium alloys is widely used in aviation and aerospace industries for its high efficiency and good quality. In order to optimize machining parameters in high-speed milling B6 titanium alloy, temperature distribution on the workpiece and the tool are analyzed, and the effect of milling parameters on milling force and milling temperature are investigated. he results show that the highest temperature appears on rake face, and near to the tool tip. With increasing of cutting time, heat affected zone on tool is bigger than that on workpiece. Milling temperature is most sensitive to the variation of milling speed, next sensitive to the variation of feed per tooth, and it is least sensitive to milling depth. Milling force is most sensitive to the variation of milling depth, next sensitive to the variation of feed per tooth, and it is least sensitive to milling speed. Introduction Cutting forces and temperature is the most important physical quantity in the cutting process. Has a close relationship with the surface integrity of the machined component. herefore, he control of cutting forces and temperature should be attention during materials processing. B6 titanium alloy is widely used in aerospace industries because of its good comprehensive mechanical properties, low density and good corrosion resistance [1]. Scholars did active study on milling force and temperature of titanium alloy. McDill et al. [2] built the thermo-mechanical model of metal cutting based on Abaqus and user-based secondary development. Molinari et al.[3] found that milling force decreased with increasing of milling speed from.1 to 73m/s. Geng et al. [4] found that milling temperature obviously increased with milling speed from 5 to m/min. Xing et al.[5] simulated the distribution of milling force and temperature of Al224. Xu et al. [6] reported that cutting force reduced with milling speed (up to 8m/min), and then increased with the further increased milling speed. Wang et al. [7] found that effect of milling speed on milling force was less than that of feed rate and milling depth. Kahles et al. [8] and King et al. [9] reported that high milling speed can reduce the milling force, and improve cutting performance and surface quality. Silva et al.[1] summarized the existing method of temperature measurement, and analyzed application scope of each method. Based on B6 titanium alloy, effects of milling parameters on milling force and temperature are studied using finite element simulation method. B6 finite element model of two-dimensional milling is built. Milling force and temperature in different parameters are analyzed, and temperature distribution on the workpiece and tool are obtained. he theoretical analysis and simulate data presented in this article provide an experimental basis for high-speed milling B6 titanium alloys. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of rans ech Publications, (ID: , Pennsylvania State University, University Park, USA-13/5/16,7:29:42)

2 Applied Mechanics and Materials Vol Simulation of high-speed milling B6 titanium Workpiece Material. he workpiece material used in all experiments is B6 alloy (i-1v-2fe- 3Al). Chemical composition of B6 is shown in able 1. Mechanical properties in normal and high temperature are shown in able 2. able 1 Chemical composition of B6(mass fraction, %) Element H O N Fe Al V i Wt pct balance able 2 Mechanical properties of B6 Normal temperature High temperature tensile strength σ b/ Mpa 5 testing temperature yield strength σ.2/ Mpa 135 tensile strength σ b/ Mpa 963 elongation δ/% 11.1 fracture strength σ / Mpa 84 shrinkage rage ψ/% 64.4 elongation δ/% 16.8 impact value а k/ J cm -2 6 shrinkage rage ψ/% 7.8 Simulation model and processing condition. AdvantEdge FEM finite element simulation software is used to simulate the milling force and milling temperature of B6. Finite element model of twodimensional milling of B6 is established by using Lagrange method, as shown in figure 1. Simulation model is shown in figure 2. Down milling and no cutting fluid were used. One 4-flute uncoated cemented carbide end mill is used. Rake angle, relief angle, helix angle, blade radius and diameter of the mill are 12º, 12º, 35º,.2mm and 1mm, respectively. Initial temperature is 2 in milling processing. vf Chip Rake face Milling cutter Relief face Workpiece Fig.1 Finite element model of two-dimensional milling Fig.2 Simulation model welve levels of milling speed, feed per tooth, milling width, and milling depth are selected to study the effect of milling parameters on milling force and temperature. Milling speed is set as 2, 4, 6, 8,, 12, 14, 16,18,, 22, 24m/min. Feed per tooth is set as.2,.3,.4,.5,.6,.7,.8,.9,.1,.15,.2,.25mm/z. Milling depth is set as 1, 2, 3, 4, 5, 5.5, 6, 6.5, 7, 8, 9, 1mm. Milling width is set as.2,.3,.4,.5,.6,.7,.8,.9, 1., 1.5, 2, 2.5mm. Analysis of simulation results Effects of milling parameters on milling force and temperature. Effect of milling parameters on milling force and temperature is shown in figure 3. As can be seen from the figure 3(a), and increase with increasing of f z from.2 to.25 mm/z. he variation range of and are [31N, 393N] and [5N, 344N]. When the f z is less than.2 mm/z, the value of is less than that of the. his is mainly because that chip thickness increases with increasing of feed per tooth, making frictional resistance and deformation resistance increase, so that deformation resistance and frictional resistance of chip and tool. Finally the milling force increase.

3 F (N) F (N) F (N) F (N) 62 Automatic Control and Mechatronic Engineering II Figure 3(b) shows that milling force increases with increasing of v c from 2 to m/min, and decreases when v c is from to 24 m/min. his may be explained as follows. First, milling temperature increases with the increase of v c. he increasing temperature decreases friction coefficient and material deformation coefficient, which finally leads to a decrease of milling force. Second, with increasing of v c, shear angle increases and shear plane becomes smaller. which leads to decrease material deformation. As a consequence, the milling force shows a decreasing tendency. Figure 3(c) shows that and increase with increasing of a e from.2 to 2.5 mm. he variation range of and are [15N, 277N] and [239N, 289N]. his is because that when a e is smaller than the cutter radius, cutting length increases with increasing of milling width. he increasing cutting length increases cutting volume, so that the milling force increases. As can be seen from figure 3(d), and linearly increase with increasing of a p. he variation range of and are [59N, 584N] and [85 N, 849 N]. his is because that the milling area increase with increasing of a p ( ) ( ) f z (mm/z) v c (m/min) (a) Effect of f z on milling force and temperature (b) Effect of v c on milling force and temperature (v c =4m/min, a p =3mm,a e =.6mm) (f z =.5mm/z, a p =3mm,a e =.6mm) a e (mm) (c) Effect of a e on milling force and temperature ( ) a p (mm) (d) Effect of a p on milling force and temperature (v c =4m/min, f z =.5mm/z,a p =3mm) (v c =4m/min,f z =.5mm/z,a e =.6mm) Fig.3 Effect of milling parameters on milling force and milling temperature Figure 3(a) shows that cutting temperature slowly rise with increasing of f z, and the variation range of milling temperature is [37, 59 ]. his may be explained as follows. First, metal removal rate increase with increasing of f z. he increasing metal removal rate increases friction coefficient, which finally leads to a increase of milling temperature. Second, the increasing f z decreases the material deformation coefficient and cutting power of cutting area and cutting volume of per unit volume. In addition, contact length of milling cutter and chip increase outgoing area of cutting calories. several factors make the temperature increase slowly. Figure 3(b) shows that milling temperature increased sharply from 286 to 72 with increasing of v c from 2 to 24m/min. his is because that removed metal of unit time increases with increasing of v c, and the increasing removed metal make generated more cutting heat. 45 ( )

4 Applied Mechanics and Materials Vol Figure 3(c) shows that milling temperature increased from to 482 when a e increase from.2 to 2.5 mm. he reason is that power consumption increase with the increased a e, led to an increase in cutting heat. However, due to the cutting length also increased, which improve thermal conditions, so milling temperature rises to a lesser extent. Figure 3(d) shows that regardless the variation of milling depth, milling temperature is maintained at about 425. his is because that cutting heat and heat-exchanging area both increases with increasing of a p, which let a p has a little effect on milling temperature. emperature field analysis. Figure 4 shows that the highest temperatures all appear on rake face, and which is near the tool tip. In figure 4(a), the highest temperature on rake face has a distance of.25mm to the tool tip. In figure 4(b), the highest temperature on rake face has a distance of.3mm to the tool tip. It is because that frictional heat gradually increased along the rake face. In metal cutting process, the chip through the first deformation zone, and outflow along the rake face. At this time, chip will produce further exacerbated deformation due to rake face extrusion and friction, the second deformation zone is formed. In this area, a large number of the heat, which is produced by friction, make contact surface temperature of chip and tool rising fast. Figure 4(a) shows that with the increase of v c, the highest temperature increase. It is because that friction of cutter and scraps increase with increasing of v c. Most heat be locked in the interface of the workpiece and tool, which led to the highest temperature appears in rack face and close to the tool tip. emperature distribution area of milling cutter reduces with increasing of v c. When the distance of relief face to tool tip is more than.1mm and the distance of rake face to tool tip is more than.15mm, milling temperature reduce with increasing of v c. his may be explained as follows. In the high milling speed, contact time of workpiece and cutter is short, which let small heat pass on the rake and relief face. Figure 4(b) shows that with increasing of f z, milling temperature increase in same place of rake and relief face emperature distribution of relief face emperature distribution of rake face emperature distribution of relief face emperature distribution of rake face (a)milling temperature distribution in different v c (b) Milling temperature distribution in different f z Fig.4 Milling temperature distribution of the rake and relief face in different milling parameters emperature distribution of workpiece and tool in different moments is shown in figure 5. Figure 5 shows that temperature on chip is significantly higher than that of the workpiece and tool. Figure 5(a) shows that the range of temperature field distribution on workpiece and tool is narrow when t=.1s. With increasing of t from.1 to.3s (in figure 5(b)), heat affected zone on tool increase sharply, while heat affected zone on workpiece increased a little bit.

5 622 Automatic Control and Mechatronic Engineering II Heat affected zone Heat affected zone Heat affected zone Heat affected zone Conclusion (a) t=.1s (b) t=.3s Fig.5 emperature distribution on the workpiece and tool in different moments (v c =16m/min, f=.5mm/z, a e =.6mm,a p =3mm) o summarize the observation, the major findings are: In the milling process, the highest temperature appears on rake face and near to the tool tip. Heat affected zone on milling cutter reduce with increasing of v c. With increasing of cutting time, heat affected zone on tool is bigger than that on workpiece. Milling force is most sensitive to the variation of milling depth, next sensitive to the variation of feed per tooth, and it is least sensitive to milling speed. Milling forces increase with increasing of feed per tooth, milling width, and milling depth. While milling force initially increases with milling speed (up to m/min) and then decreases with the further increased milling speed. Milling temperature is most sensitive to the variation of milling speed, next sensitive to the variation of feed per tooth, and it is least sensitive to milling depth. Milling temperature increase with increasing of feed per tooth, milling speed, and milling width. Acknowledgment his work was financially supported by the National Natural Science Foundation of China (Grant NO ), Aeronautical Science Foundation of China (212ZE5361), and graduate starting seed fund of Northwestern Polytechnical University (Z21348). References [1] M. Wang, X. Meng, Z. Liao, in: DEV APPL MAER, vol. 24(9), p (in Chinese) [2] J. M. McDill, Lindgren, Lars-Erik, R. C. Reed, A. S. Oddy, in: International Conference on Processing and Manufacturing of Advanced Materials, Lasvegas, USA, (),p.4-8. [3] A. Molinari, C. Musquar, G. Sutter, in: IN J PLASICIY, vol. 18 (2), p [4] G. SH. Geng, J. H. Xu, Y. C. Fu, in: Mechanical Science and echnology for Aerospace Engineering, vol. 25(3)(6), p [5] D. L. Xing, J. H. Zhang, Y. F. Zhao, X. H. Shen, in: ool Engineering, vol. (9)(21),p [6] J. H. Xu, G. S. Geng, in: J. Mater. Process echnol., vol.129 (2), p [7] Z. G. Wang, Y. S. Wong, M. Rahman, in: Int. J. Mach. ools Manuf., Vol. 45(1) (5), p [8] P. I. King, R. L.Vaughn. in: High Speed Machining, edited by Komanduri, Subramanian K et al. ASME, U.S.A, (1984),p.1-3. [9] J. F. Kahles, M. Field, S. M. Harvey, in: Annals of CIRP, vol. 27(2)(1978),p [1] Marcio Bacci da Silva and Jame Wallbank, in: J. Mater. Process echnol., vol. 88 (1999), p

6 Automatic Control and Mechatronic Engineering II 1.428/ Simulation for Cutting Force and emperature in High-Speed Milling of B6 itanium Alloy 1.428/ DOI References [3] A. Molinari, C. Musquar, G. Sutter, in: IN J PLASICIY, vol. 18 (2), p /S (1)3-1 [6] J. H. Xu, G. S. Geng, in: J. Mater. Process echnol., vol. 129 (2), pp /S (2)645-3