基于切宽张量的非球头刀端铣自由曲面编程方法

发布时间：2018-02-05 04:43

本文关键词： 自由曲面端铣加工数控编程切宽张量加工区域划分　出处：《南京航空航天大学》2016年硕士论文　论文类型：学位论文

【摘要】：结合国家科技重大专项、江苏省杰出青年基金项目及企业的实际需求,针对飞机进气道鼓包、翼身融合曲面等自由曲面类零件几何特性复杂、加工精度要求苛刻导致数控端铣加工效率低下的问题,本文对自由曲面端铣加工编程方法进行了深入研究,主要成果如下:(1)提出了非球头刀端铣加工切宽张量。针对现有非球头刀切宽求取方法效率低的问题,定义了刀具有效切削曲面,将非球头刀在曲面上一点沿各进给方向运动时不断变化的二维刀具有效切削轮廓转换为一个在绝对坐标系中不变的三维连续曲面,通过分析刀具有效切削曲面与零件曲面的法向逼近距离,推导了非球头刀端铣加工切宽张量,实现了曲面上任一点处最大切宽进给方向的高效求解。(2)提出了基于非球头刀切宽张量的自由曲面加工区域划分方法。针对复杂自由曲面各离散点最大切宽进给方向存在区域化分布的情况,构建曲面切宽张量场,基于张量场退化点在曲面上构造一系列空间曲线,将曲面划分为不同加工区域,每个加工区域内的曲面离散点最大切宽进给方向连续分布。(3)研究了基于非球头刀切宽张量的自由曲面分区加工轨迹生成方法。对于曲面中包含的任一加工区域,以平均切宽最大为原则提取初始加工轨迹,以最大允许残留高度为约束,通过偏置初始轨迹线生成理论最优轨迹线为加工轨迹,并给出了偏置轨迹丢失、曲面边界残留等情况的处理方法,实现了切宽最大化的自由曲面分区加工轨迹生成。(4)根据以上研究内容,基于CATIA CAM平台,开发了基于非球头刀切宽张量的自由曲面数控编程系统,并选取了具体实例进行了应用验证,验证结果表明本文的研究成果可以有效提高自由曲面端铣精加工效率。
[Abstract]:Combined with the important national science and technology project, Jiangsu outstanding youth fund project and the actual demand of enterprises, the geometric characteristics of the free-form curved surface parts such as airplane inlet drum bag, wing body fusion surface and so on are complex. The problem of low efficiency of NC end milling due to harsh machining precision is discussed in this paper. The programming method of free-form surface end milling is deeply studied in this paper. The main results are as follows: 1) the cutting width Zhang Liang of non-ball cutter end milling is put forward. Aiming at the low efficiency of the existing non-ball cutter cutting width calculation method, the effective cutting surface of the tool is defined. The effective cutting profile of a 2-D cutter with a non-spherical cutter moving along each feed direction on the surface is transformed into a three-dimensional continuous surface which is invariant in the absolute coordinate system. Based on the analysis of the normal approaching distance between the effective cutting surface and the part surface, the cutting width Zhang Liang of the non-ball end milling tool is deduced. An efficient solution to the feed direction of the maximum tangent width at any point on the surface is realized. In this paper, a method of dividing the machining area of free form surface based on Zhang Liang with non-spherical cutter cutting width is proposed, and the regional distribution of the feed direction of the maximum tangent width of each discrete point of complex free form surface is discussed. A series of spatial curves are constructed on the surface based on the degraded point of the Zhang Liang field, and the surfaces are divided into different processing areas. Continuous distribution of the maximum tangential width feed direction of the discrete point of the curved surface in each machining area. In this paper, a method of generating free-form surface machining trajectory based on non-spherical cutter width Zhang Liang is studied. For any machining region included in the surface. The principle of maximum average cutting width is used to extract the initial machining trajectory, the maximum allowable residual height is taken as the constraint, the theoretical optimal trajectory is generated by the bias initial trajectory line, and the offset trajectory loss is given. According to the above research content, the processing method of surface boundary residue and other cases, realizing the maximum cutting width of free-form surface machining path generation. 4) based on CATIA CAM platform. A NC programming system of free-form surface based on non-spherical cutter width Zhang Liang is developed, and an example is selected to verify the application. The verification results show that the research results in this paper can effectively improve the efficiency of end-milling machining of free-form surfaces.
【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】：2016
【分类号】：V261.2

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