【作者】 冯焕琴；

【导师】 杨兆军；

【作者基本信息】 吉林大学 ， 机械制造及其自动化， 2004， 硕士

【摘要】 随着微小机械技术的发展，微小轴类零件的加工技术日益受到重视。传统机械加工方法，由于切削力的存在，对于直径在数十至数百微米的微小轴，特别是微小细长轴的加工十分困难的。放电加工，由于宏观上没有力的作用，因此非常适合于微小轴类零件或异形轴类零件的加工。 本文对放电磨削加工的国内外研究现状进行了综合评述。结果发现，应用放电磨削加工微细轴的实验设备均为实验室研制的专门放电磨削装置，这种装置不仅价格贵，而且应用范围也比较窄。我们分析了放电磨削的原理，认为若对通用线切割机床进行改造，增加一些机构将可能实现放电磨削加工。再通过对放电磨削工艺的研究，可能会形成一种基于线切割机床的线电极放电磨削工艺，从而使放电磨削加工工艺易于实现和推广。因此提出了基于线切割机床的线电极放电磨削工艺方法。 1．放电磨削工件表面质量的研究及改进 本文分析了放电磨削工件的表面质量及影响表面质量尤其是表面粗糙度的因素。表面质量包括表面粗糙度、表面变质层和表面机械性能三个部分，放电磨削加工表面粗糙度通常用微观轮廓平面度的平均算术偏差R_a或用微观轮廓平面度的最大高度值R_max表示的。对表面粗糙度影响最大的是单个脉冲能量，因为脉冲能量大，每次脉冲放电蚀除量也大，从而使工件表面粗糙度恶化。影响表面质量的因素包括脉冲电源的相关参数、工件和机床的一些因素。并着重介绍了影响工件表面粗糙度的几个电参数。通过对机床部分机械装置诸如工作台的传动精度、导轮等方面进行了调整，选择合适的工作液，并分析了机床的电源系统，实施并提出了一些降低放电磨削工件表面粗糙度的方法。 2．放电磨削辅助装置的研制 摘要.....甲...叫...... 通用线切割机床实现放电磨削加工的关键在于加装工件主轴系统。本文首先研制了工件主轴系统，实现了通用线切割机床的线电极放电磨削。试验所用机床的电流不能满足微小轴加工需要，试验通过串接电阻的方法得到较小的加工电流。放电电源系统的改造，有效的降低了单个脉冲的放电能量，从而达到降低放电磨削工件表面粗糙度的目的。电极丝的振动对工件表面粗糙度影响很大，试验采用缩短电极丝长度和加装电极丝限位装置两种方法相结合来控制电极丝的振动，线切割机床的电极丝长度可以通过改变电极丝导轮之间的距离来改变，此过程可以通过机床调整实现;另一种方法就是加装电极丝限位装置，装置加装在线切割机床X轴进给机构的横梁上，有效的减小了电极丝的抖动。3.放电磨削工艺参数的选择及试验 在改造了设备的基础上对放电磨削微小轴进行了研究。工艺参数的合理选择对表面粗糙度也有很大的影响。为了研究不同的加工条件对表面粗糙度（几）的影响，根据正交优化设计研究了串接电阻、工件主轴系统转速等加工参数对表面粗糙度的影响规律。采用二次回归正交优化组合设计的方法，得到自然因素水平及编码表，然后设计出试验方案，并根据所提供的参数加工出了的粗糙度试件，用HL一H型原子力显微镜（AFM）测得工件表面粗糙度，通过实验分析得出在本文的试验条件下的优化工艺参数。运用这些装置和优化后的参数进行放电磨削加工，采用多次切割的方法，成功的加工出直径80 pm的微小轴和直径100 pm的微扁钻头，轴的表面粗糙度可以达到0.3协m以下。更多还原

【Abstract】 With the development of micro mechanical technology, the process technology of micro-axial is playing an important role in micro machine producing. Because of the cutting force, routine machine finishing is very difficult to manufacture micro-axial of diameter range from 10 to 100 u m ,especially the axial with large length-diameter ratio. Without the macro cutting force, Electro-discharge machining is fit to manufacture micro-axial and shaped-axial.The article analysis world widely research about WEDG. The conclusion: the experimental equipment of manufacture micro-axial by WEDG is special discharge grinding apparatus triturated by laboratory itself. Not only the equipment cost is higher, but the field of application is narrow. To analysis the working element of WEDG, we believe, wire electrode cutting machine may get the function of WEDG by adding the auxiliary device. Then by study the craft of WEDG, we may get a kind of WEDG craft based on the wire electric cutting machine. So the craft of WEDG is easy to accomplish and be used popularly. 1. The study and disease on mass and roughness of surfacethe article analysis the affecting factors to the mass and roughness of surface in WEDG machining. The mass consists of the roughness of surface, the envenomation and mechanical character. In common, the surface roughness of WEDG is indicated by Ra and Rmax . The largest affecting factor to surface roughness is simple pulse energy, for the larger the simple pulse energy, the larger the erosion, the worse the roughness of surface. By adjust the accuracy of the machinery, choice the treatment fluid and analysis the power, we get some ways to deceasethe roughness of surface.2. Manufacture the auxiliary device of wire electrode machineAbout wire electrode cutting machine: the essential different between WEDM and WEDG is chief axial system. First the article get the function of WEDG in wire electrode machine by manufacture the chief axial system; Second the current of wire electrode machine dose not meet the challenge of micro-machining. We get different current by series resistance and decease the simple pulse energy, then decease the roughness of surface; the tremble of wire electrode influence the roughness of surface greatly. We decease the tremble of wire electrode by shortening the length of wire electrode and adding the limit apparent of wire electrode. The apparent lays in X-axial bridging beam in wire electrode machine. 3.The study and experiment of processing parameterBase on remodeling the apparent, the article study the manufacture the micro-axial by WEDG, the rational choice of electric spark forming processing parameter influences the roughness of surface greatly. To study difference parameters causing difference roughness of surface, through orthogonal optimum design the experiment get natural factor level and code pattern, then design testing program, produce the specimens test coupon. By using HL-II flying-spot microscope, the experiments get boundary data of coupons, Using orthogonal design method analysis the experiment data, get optimum regression equation, then get optimum processing parameter. In electric spark forming multiple cutting may get higher roughness of surface, so the experiment cut several times using optimum processing parameter and get =80 m micro-axial and = 100 m micro-cutting, the roughness of axialsurface is Ra<0. 3 m.更多还原