Parameters Optimization of SiC Abrasive Assisted Simultaneous EDM and ECM Machining of Titanium Alloy
-
摘要: 针对钛合金的难加工特点,单纯EDM、ECM的局限性以及EDM和ECM串行加工的低效率问题,在低电阻去离子水中加入碳化硅磨粒,开展了磨粒辅助作用下的EDM和ECM并行复合加工。将材料去除率、电极损耗率和表面粗糙度作为评价指标,通过正交试验和灰关联度分析,将多工艺目标转化为单一评价指标,得到峰值电流、脉冲宽度、磨粒浓度和放电电压主要工艺参数的优化组合,并进行了试验验证。结果表明:峰值电流为1.5 A、脉冲宽度为30 μs、磨料浓度为5 g/L、放电电压为40 V的工艺参数组合所得到的电极损耗率、表面粗糙度和表面形貌都得到明显改善。Abstract: In view of the difficult machining characteristics of titanium alloy, the limitations and low efficiency of EDM & ECM serial machining, silicon carbide abrasive was added into the deionized water with low resistance, and simultaneous EDM and ECM machining assisted by abrasive was carried out. Taking material removal rate, tool wear rate and surface roughness as the evaluation indexes, the multi process objectives are transformed into a single evaluation index by using the orthogonal test and grey correlation analysis, and the optimized combination of main process parameters, such as peak current, pulse on time, abrasive concentration and discharge voltage, is obtained and verified via experiments. The results show that the tool wear rate, surface roughness and surface morphology are obviously improved at a peak current of 1.5 A, pulse on time of 30 μs, abrasive concentration of 5 g/L and discharge voltage of 40 V.
-
Key words:
- titanium alloy /
- EDM /
- simultaneous processing /
- parameters optimization
-
表 1 工件、工具电极和磨粒的材料性能
名称 材料 密度/(g·cm-3) 热导率/(W·(m·K)-1) 熔点/℃ 工件 Ti-6Al-4V 4.43 7.96 1 660 工具电极 紫铜 8.96 397 1 083 磨粒 SiC 3.2 83.6 2 700 表 2 工艺参数试验水平表
水平 峰值电流A/A 脉冲宽度B/μs 磨粒浓度C/g·L-1 放电电压D/V 1 1.5 15 0 30 2 3 30 5 40 3 4.5 60 12 50 表 3 正交试验结果
序号 A B C D RMRR/(mg·s-1) RTWR/(mg·s-1) Ra/μm 1 1 1 1 1 0.017 8 0.009 8 2.817 2 1 2 2 2 0.027 2 0.008 0 2.703 3 1 3 3 3 0.042 7 0.012 7 4.001 4 2 1 2 3 0.054 5 0.010 0 3.226 5 2 2 3 1 0.093 0 0.018 5 3.863 6 2 3 1 2 0.063 7 0.012 3 4.406 7 3 1 3 2 0.094 0 0.021 7 3.934 8 3 2 1 3 0.096 8 0.020 2 3.717 9 3 3 2 1 0.104 8 0.012 5 4.138 表 4 比较序列无量纲化处理结果
序列 RMRR RTWR Ra 1 0 0.131 4 0.067 0 2 0.108 1 0 0 3 0.286 2 0.343 1 0.762 2 4 0.421 8 0.146 0 0.307 2 5 0.864 4 0.766 4 0.681 2 6 0.527 6 0.313 9 1 7 0.878 2 1 0.722 8 8 0.908 1 0.890 5 0.595 4 9 1 0.328 5 0.842 6 表 5 灰色关联系数及灰关联度数值
序列 RMRR RTWR Ra 灰关联度 1 1 0.791 9 0.881 8 0.891 2 2 0.822 2 1 1 0.940 7 3 0.636 0 0.593 1 0.396 1 0.541 7 4 0.542 4 0.774 0 0.619 4 0.645 3 5 0.3665 0.394 8 0.423 3 0.394 7 6 0.486 6 0.614 3 0.333 3 0.478 1 7 0.362 8 0.333 3 0.408 9 0.368 3 8 0.355 1 0.359 6 0.456 5 0.390 4 9 0.333 3 0.603 5 0.372 4 0.436 4 表 6 针对MRR的单工艺目标平均关联度系数
水平 A B C D 1 0.819 4 0.635 1 0.613 9 0.566 6 2 0.465 2 0.514 6 0.566 0 0.557 2 3 0.350 4 0.485 3 0.485 3 0.511 2 极差 0.469 0 0.149 8 0.158 8 0.055 4 表 7 针对TWR的单工艺目标平均关联度系数
水平 A B C D 1 0.795 0 0.633 1 0.588 6 0.596 7 2 0.594 4 0.584 8 0.792 5 0.649 2 3 0.432 1 0.603 6 0.440 4 0.575 6 极差 0.362 9 0.048 3 0.352 1 0.073 6 表 8 针对Ra的单工艺目标平均关联度系数
水平 A B C D 1 0.759 3 0.636 7 0.557 2 0.559 2 2 0.465 2 0.626 6 0663 9 0.580 7 3 0.412 6 0.367 3 0.409 4 0.490 7 极差 0.346 7 0.269 4 0.254 5 0.090 0 表 9 多工艺目标平均关联度系数
水平 A B C D 1 0.791 2 0.634 9 0.586 6 0.574 1 2 0.506 0 0.575 3 0.674 1 0.595 7 3 0.398 4 0.485 4 0.434 9 0.525 8 极差 0.392 8 0.149 5 0.239 2 0.069 9 表 10 试验验证与评价指标的对比
评价指标 A1B2C2D2 A2B1C2D3 A1B1C2D2 RMRR 0.027 2 0.054 5 0.026 8 RTWR 0.008 0 0.010 0 0.007 7 Ra 2.703 3.226 2.578 -
[1] 梁旭, 蔡重延, 安庆龙, 等. TC4铣削中超临界CO2混合油膜附水滴的冷却润滑性能[J]. 中国机械工程, 2020, 31(3): 328-335 doi: 10.3969/j.issn.1004-132X.2020.03.011LIANG X, CAI C Y, AN Q L, et al. Cooling and lubrication performance of scCO2 mixed with OoW in TC4 milling[J]. China Mechanical Engineering, 2020, 31(3): 328-335 (in Chinese) doi: 10.3969/j.issn.1004-132X.2020.03.011 [2] 费亚, 黄云, 邹莱, 等. 预应力砂带磨削钛合金表面完整性的试验研究[J]. 机械科学与技术, 2017, 36(7): 1063-1067 doi: 10.13433/j.cnki.1003-8728.2017.0713FEI Y, HUANG Y, ZOU L, et al. Experimental study on surface integrity of titanium alloy machined by prestressed abrasive belt grinding[J]. Mechanical Science and Technology for Aerospace Engineering, 2017, 36(7): 1063-1067 (in Chinese) doi: 10.13433/j.cnki.1003-8728.2017.0713 [3] JUNG H J, HAYASAKA T, SHAMOTO E, et al. Suppression of forced vibration due to chip segmentation in ultrasonic elliptical vibration cutting of titanium alloy Ti-6Al-4V[J]. Precision Engineering, 2020, 64: 98-107. doi: 10.1016/j.precisioneng.2020.03.017 [4] LIN M Y, TSAO C C, HUANG H H, et al. Use of the grey-Taguchi method to optimise the micro-electrical discharge machining (micro-EDM) of Ti-6Al-4V alloy[J]. International Journal of Computer Integrated Manufacturing, 2015, 28(6): 569-576 doi: 10.1080/0951192X.2014.880946 [5] GAO P, WANG X B, LIANG Z Q, et al. Effects of machining inclination angles on microgroove quality in micro ball end milling of Ti-6Al-4V[J]. International Journal of Advanced Manufacturing Technology, 2017, 92: 2725-2734 doi: 10.1007/s00170-017-0305-2 [6] 郭妍, 贾云海, 郭建梅, 等. 基于正交试验分析的电火花放电磨削聚晶立方氮化硼复合片工艺[J]. 工具技术, 2019, 53(3): 64-68 https://www.cnki.com.cn/Article/CJFDTOTAL-GJJS201903014.htmGUO Y, JIA Y H, GUO J M, et al. Electrical discharge grinding polycrystalline cubic boron nitride composites based on orthogonal experiment analysis[J]. Tool Engineering, 2019, 53(3): 64-68 (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-GJJS201903014.htm [7] LIU H Z, WANG Z L, WANG Y K, et al. Effect of technological parameters on the process performance of pure Al2O3 layer of Ni-Al2O3 FGMs by self-induced EDM[J]. International Journal of Advanced Manufacturing Technology, 2017, 90: 3633-3641 doi: 10.1007/s00170-016-9631-z [8] LIANG J F, LIAO Y S, KAO J Y, et al. Study of the EDM performance to produce a stable process and surface modification[J]. International Journal of Advanced Manufacturing Technology, 2018, 95: 1743-1750 doi: 10.1007/s00170-017-1315-9 [9] BHAUMIK M, MAITY K. Effect of different tool materials during EDM performance of titanium grade 6 alloy[J]. Engineering Science and Technology, An International Journal, 2018, 21(3): 507-516 doi: 10.1016/j.jestch.2018.04.018 [10] 孙树峰, 计时鸣, 谭大鹏, 等. 磨粒辅助EDM与ECM复合加工技术[J]. 机械工程学报, 2012, 48(17): 159-164 https://www.cnki.com.cn/Article/CJFDTOTAL-JXXB201217024.htmSUN S F, JI S M, TAN D P, el al. Abrasive assisted EDM & ECM compound machining[J]. Journal of Mechanical Engineering, 2012, 48(17): 159-164 (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-JXXB201217024.htm [11] MASUZAWA T, SAKAI S. Quick finishing of WEDM products by ECM using a mate-electrode[J]. CIRP Annals, 1987, 36(1): 123-126 doi: 10.1016/S0007-8506(07)62568-2 [12] RAMASAWMY H, BLUNT L. 3D surface topography assessment of the effect of different electrolytes during electrochemical polishing of EDM surfaces[J]. International Journal of Machine Tools and Manufacture, 2002, 42(5): 567-574 doi: 10.1016/S0890-6955(01)00154-7 [13] NGUYEN M D, RAHMAN M, WONG Y S. Transitions of micro-EDM/SEDCM/micro-ECM milling in low-resistivity deionized water[J]. International Journal of Machine Tools and Manufacture, 2013, 69: 48-56 doi: 10.1016/j.ijmachtools.2013.03.008 [14] YIN Q F, WANG B R, ZHANG Y B, et al. Research of lower tool electrode wear in simultaneous EDM and ECM[J]. Journal of Materials Processing Technology, 2014, 214(8): 1759-1768 doi: 10.1016/j.jmatprotec.2014.03.025