Ti6Al4V的电火花线切割加工参数及工艺研究

发布时间：2018-01-18 07:09

本文关键词：Ti6Al4V的电火花线切割加工参数及工艺研究　出处：《太原理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：伴随工业领域的逐渐发展,实际应用中对产品性能要求的不断提高,工业产品所采用的材料也愈加受到关注,而Ti6Al4V(简称TC4)自起诞生之日起,就因其优秀的性能而备受科学界关注,也不断地应用于航空、运输、艺术、采油、冶炼、船舶、电力装备等多个重要领域。由于钛合金较高的比强度与热稳定性,和较低的导热系数,较小的弹性模量等原因,利用车削铣削等传统加工手段对Ti6Al4V进行加工时,切削刃附近的产热大且散热慢,极易造成刀具与材料的粘连以及刀具的损坏。而属于电加工范畴的电火花线切割(WEDM)加工,切割过程中电极丝和被加工材料不接触,能够减少部分刀具损坏的问题。从而研究WEDM加工Ti6Al4V中的部分电参数以及其工艺参数对材料的影响就较有价值。本文面向WEDM电参数与工艺参数进行了以下研究:(1)通过多因素序贯实验中常用的最陡坡度法,寻找一组出色的电参数组合以满足对加工TC4合金性能指标要求,分别考虑WEDM的电参数对材料去除率MRR以及表面粗糙度值Ra的影响,并寻找到对应于各个目标的最优试点,即最优参数组合。但是若只一考量其中一个目标,则通过参数的改变提高其中一个目标时常常会导致另一个目标值的下降,而加工中往往需要综合考量上述两目标,故结合灰色关联分析的方法,将不同参数下对应的材料去除率MRR与表面粗糙度值Ra的关联度值相加,从而得到综合性能最好的一组电参数值。(2)通过曲面响应方法分析验证各电参数对材料去除率及表面粗糙度值影响关系,结合软件对加工参数对材料去除率以及表面粗糙度值的影响加以预测分析并将结果公式化,从而优化电参数组合,并在实际应用将所得到的最优电参数组合输入到工控机的操作系统中,从而始加工所得Ti6Al4V材料达到较为出色的综合性能。(3)从工艺的角度研究了电火花线切割锥度切割功能,为研究上述问题,本文采取了单因素结合AHP分析,以及正交实验的方法,对WEDM的各个电参数及非电参数对材料去除率以及表面粗糙度值的影响进行了试验分析,其中电参数包括对材料去除率影响较大的峰值电流与脉冲宽度,非电参数包括切割方向以及切割角度(锥度),而快走丝电火花线切割机床锥度加工的切割角度只能在-3°至3°之间(实际测量为-2°58′至2°59′)。通过研究分析得出影响锥度加工材料去除率以及表面粗糙度的主要因素及影响显著程度。(4)通过ANSYSWORKBENCH模拟仿真放电加工产热的过程结合前人研究说明了在电加工条件下,放电通道半径的大小直接关系到材料的粗糙度值大小,结合放电通道半径的经验公式可以分析出影响表面粗糙度的两个最为重要的因素,并且通过利用扫描电镜观测各参数变化对变质层的影响。
[Abstract]:With the gradual development of the industrial field and the continuous improvement of product performance requirements in practical applications, the materials used in industrial products have been paid more and more attention. Ti6Al4V (abbreviated as TC4) has been concerned by the scientific community for its excellent performance since its birth, and has been continuously applied in aviation, transportation, art, oil extraction, smelting and shipping. Because of the higher specific strength and thermal stability of titanium alloy, the lower thermal conductivity and the lower elastic modulus, etc. When Ti6Al4V is processed by turning and milling, the heat production near the cutting edge is large and the heat dissipation is slow. It is easy to cause adhesion of cutting tools and materials and damage of tools. WEDM, which belongs to the category of electrical machining, does not contact electrode wire and processed materials in the process of cutting. It is valuable to study some electrical parameters in WEDM machining Ti6Al4V and the influence of process parameters on the material. This paper is oriented to the electrical parameters and engineering of WEDM. The following studies were carried out on the art parameters:. (. The main results are as follows: 1) the steepest gradient method is commonly used in sequential experiments. To find an excellent combination of electrical parameters to meet the requirements of the mechanical properties of TC4 alloys, the effects of electrical parameters of WEDM on the material removal rate (MRR) and surface roughness value Ra were considered respectively. And find the optimal pilot corresponding to each goal, that is, the optimal combination of parameters. But if only one of the objectives is considered. The improvement of one of the targets by changing the parameters often leads to the decrease of the value of the other target, and the two targets need to be considered comprehensively in the process, so the method of grey correlation analysis is combined. The correlation value between the material removal rate (MRR) and the surface roughness value (Ra) is added under different parameters. A group of electrical parameters, which have the best comprehensive performance, is obtained. The surface response method is used to verify the relationship between the electrical parameters and the material removal rate and the surface roughness value. The influence of machining parameters on material removal rate and surface roughness value is predicted and analyzed with software, and the results are formulated to optimize the combination of electrical parameters. The optimal electrical parameters are input into the operating system of the industrial control computer in practical application. Thus, the Ti6Al4V material obtained from the process has achieved excellent comprehensive properties. (3) the taper cutting function of WEDM has been studied from the point of view of technology, in order to study the above problems. In this paper, single factor AHP analysis and orthogonal experiment were used to analyze the effect of WEDM's electrical and non-electrical parameters on the material removal rate and surface roughness value. The electrical parameters include the peak current and pulse width which have great influence on the material removal rate, and the non-electric parameters include the cutting direction and the cutting angle (taper). The angle of taper machining of WEDM can only be between 3 掳and 3 掳(actual measurement is 2 掳58'to 2 掳59 掳). The main factors affecting the removal rate and surface roughness of taper machining materials and the degree of significance are obtained by means of research and analysis. The heat production process of electric discharge machining is simulated by ANSYSWORKBENCH and the former research shows that under the condition of electromachining. The magnitude of the discharge channel radius is directly related to the roughness value of the material. The two most important factors affecting the surface roughness can be analyzed by combining the empirical formula of the discharge channel radius. The influence of various parameters on the metamorphic layer was observed by scanning electron microscope (SEM).
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG484

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