高速往复走丝电火花线切割电极丝空间形位变化控制研究

发布时间：2018-05-24 19:07

本文选题：高速往复走丝 + 空间形位　；参考：《南京航空航天大学》2017年硕士论文

【摘要】：高速往复走丝电火花线切割机床在放电加工过程中,电极丝不仅要受到放电爆炸力、电场力、磁场力、工作液阻尼力等各种力的交互作用,还会受到导轮、丝筒和轴承跳动等的影响,因而电极丝空间形位的稳定性较差,导致高速往复走丝电火花线切割的加工精度不高,对于多次切割(俗称“中走丝”)、大锥度切割和大厚度切割的影响更大。在此背景下,本课题设计并制作了高速往复走丝恒张力走丝控制机构和新型防断丝智能导丝器,对加工过程中电极丝的空间形位进行了有效控制,并在此基础上进行了多次切割、大锥度切割和大厚度切割的工艺试验研究,主要的工作内容如下:(1)利用NX6.0软件进行恒张力走丝控制机构的设计与制作,实现了对电极丝张力的有效控制,控制精度在1N以内。(2)利用NX6.0软件设计并制作了新型防断丝智能导丝器,提高了电极丝空间定位的精度和稳定性,在降低电极丝的磨损的同时,还消除了烧丝、短路现象,延长了电极丝的使用寿命。(3)同时采用恒张力走丝控制机构和新型防断丝智能导丝器进行工艺试验,与传统机床相比,切割效率和精度分别提升约10%和20%,表面粗糙度降低约20%。(4)对现有的大锥度高速往复走丝线切割的电极丝定位方式进行了分析,讨论了现有大锥度导丝机构的不足并设计了两种大锥度随动导丝机构,最终确定了采用了无磨损有交切误差的导丝机构,并通过实验证明了该机构可以大大改善锥度切割的表面质量及精度,并且适合大锥度的多次切割。(5)研究分析了大厚度多次切割工件“腰鼓度”的影响因素,建立了多次切割电极丝的受力模型,通过改变走丝速度、修刀补偿量、电极丝直径等条件进行了多次切割实验。结果表明:大厚度多次切割时,极间的放电爆炸力是促使电极丝产生挠度最终导致切割工件“腰鼓度”的主要原因,可通过适当地增大电极丝直径和张紧力加以改善。
[Abstract]:In the process of discharge machining, the electrode wire is not only subjected to the interaction of various forces, such as discharge explosion force, electric field force, magnetic field force, working fluid damping force and so on, but also to the guide wheel. Because of the influence of wire cylinder and bearing runout, the stability of electrode wire in space position is poor, which leads to the low precision of high speed reciprocating wire WEDM. For multiple cutting (commonly known as "middle thread"), large taper cutting and large thickness cutting have more influence. Under this background, the paper designs and manufactures a high speed reciprocating wire constant tension wire control mechanism and a new type of intelligent wire guide for preventing breaking, which effectively controls the space configuration of the electrode wire in the process of processing. On the basis of this, the process test of cutting, large taper cutting and large thickness cutting is carried out. The main work is as follows: 1) Design and manufacture of constant tension thread control mechanism by using NX6.0 software. The effective control of wire tension is realized, and the control precision is within 1N. (2) A new type of intelligent wire guide is designed and manufactured by using NX6.0 software, which improves the precision and stability of electrode wire positioning, and reduces the wear of electrode wire at the same time. It also eliminates the phenomenon of wire burning and short circuit, prolongs the service life of electrode wire. It also uses constant tension wire walking control mechanism and a new type of intelligent wire guide device to carry out process tests. Compared with the traditional machine tool, The cutting efficiency and precision are increased by about 10% and 20% respectively, and the surface roughness is reduced by about 20%. This paper discusses the deficiency of the existing large taper guide wire mechanism and designs two kinds of large taper following wire guiding mechanism. Finally, the guide wire mechanism with no wear and intersecting error is adopted. It is proved by experiments that the mechanism can greatly improve the surface quality and precision of taper cutting, and the influence factors of the "waist drum" of the workpiece with large thickness and multiple cutting are studied and analyzed. The stress model of multiple cutting electrode wire was established, and several cutting experiments were carried out by changing the speed of wire walking, the compensation amount of cutter, the diameter of electrode wire, and so on. The results show that the explosive force between the electrodes is the main cause of the deflection of the electrode wire, which can be improved by increasing the wire diameter and tensioning force.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG484

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