共查询到18条相似文献,搜索用时 828 毫秒
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提出了一种适用于五轴数控加工刀具干涉处理的特征投影法。该方法以刀具系为检测基准,以曲面特征点为检测对象,判断特征点是否落入刀具系表面内部来进行干涉检查;以干涉量最大的方向确定干涉消除平面,以此来计算旋转刀轴所需的消除角度。并将刀具系和曲面特征点投影到一个特定平面上,只对可能发生干涉的曲面特征点进行干涉检测,从而大大提高干涉处理效率。 相似文献
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数控加工中的刀位干涉检查 总被引:1,自引:1,他引:0
干涉检查是数控加工的关键问题之一,本文提供了一套可靠的干涉检查算法。介绍了研制CAX系统的基本原则;说明刀位计算方法;详细讨论曲面间、曲面自身及边界部位的干涉检查算法,其方法均是首先将曲面离散为三角小平面,然后计算球头刀球心至有界三角小平面的距离。该距离即作为判断干涉与否的依据。运行表明,算法可靠,效率较高。附有若干实例。 相似文献
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曲面间的干涉检查和间隙计算是计算机辅助布局设计、加工干涉,动态模拟的重要模块。本文提出了一种雕塑曲面间最小距离的计算方法,给出实例,并分析了算法的速度、可靠性及进一步需开发的工作等。 相似文献
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针对复杂曲面环形刀五轴数控加工中的局部干涉问题,提出了一种基于曲率匹配及网格点的干涉处理技术。首先,利用曲率匹配原则选出合理的刀具半径,以保证在切触点处沿任何方向上刀具与被加工曲面之间不会发生干涉,然后在各个切触点处通过比较刀具曲面最小主曲率与加工曲面最大主曲率确定出刀具的初始倾角。为了判断切触点邻近区域是否存在干涉问题,采用了网格点来快速自动生成检测区域及初始检测点。文中对有效检测点的筛选以及干涉的判断和处理技术分别进行了详细论述。最后,以非均匀有理B样条曲面为加工实例,对上述算法进行了测试和验证。 相似文献
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为减小非可展直纹面侧铣过程中产生的原理误差,提出一种新的刀具加工轨迹优化方法,将曲面匹配方法应用于初始刀具加工轨迹的优化过程,并使用序列二次规划算法求解曲面匹配问题。首先,采用现有的刀具加工轨迹生成方法得到刀轴轨迹曲面;其次,对刀轴轨迹曲面进行法向偏移得到对应的刀具加工包络面并进行原理误差计算,使用基于序列二次规划算法的曲面匹配方法对加工包络面与设计曲面进行曲面逼近,得到空间变换矩阵;再次,通过空间变换和法向偏移,得到优化后的刀轴轨迹曲面及其对应的刀具加工包络面,以及对应的优化刀具加工轨迹及加工误差分布数据;最后,使用MATLAB进行仿真,并与基于最小二乘法的曲面匹配方法进行对比验证。仿真结果表明该优化方法有效地减小了初始刀具加工轨迹产生的原理误差,这说明提出的方法能够用于减小非可展直纹面侧铣加工时产生的原理误差。研究成果为提高非可展直纹面侧铣的精度提供了新的技术支持。 相似文献
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自由曲面的CNC直接插补加工技术 总被引:5,自引:0,他引:5
在CNC系统上直接根据曲面几何定义与加工工艺参数对多轴贡面加工的连续运动轨迹进行实时插补控制,在CNC上直接在APT高级语言编程,极大地科化了零件程序,并可在线修改与补偿机床运动结构、刀具形状尺寸及加工作量等工艺参数,使曲在线曲面精加工经济而高效。在单CPU硬件环境下实现了从一般二次曲线到复杂的参数组合曲面,从两轴加工到复杂的五轴联动功能,可采用多种加工刀具与加工方式,可实时检测与处理刀具干涉,并 相似文献
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无氧铜超精加工表面微观形貌的分形维数表征 总被引:1,自引:0,他引:1
单点金刚石超精密加工能够获得纳米级的低粗糙度表面。进一步的实验表明,采用该工艺进行退火态无氧铜切削,已加工表面在刀痕基础上还会出现清晰的晶界浮凸现象。传统的粗糙度概念无法有效表征与区分含有晶界浮凸信息的超精加工表面微观形貌。引入分形维数概念,采用该理论中尺码法对无氧铜超精加工表面的微观形貌进行分形维数计算;为降低切削刀痕信号干扰、突出晶界浮凸信息,设计表面信号带阻滤波方法。计算结果表明,超精加工后的表面分形维数包含了加工刀痕与晶界浮凸信息,由于两者尺度相近,传统的粗糙度测量无法区分其差异;采用带阻滤波与尺码法耦合方式,能够有效识别晶界浮凸特点,定量地反映微观尺度下超精加工表面的形貌特征信息。 相似文献
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Detecting and removing gouges in the process of toolpath generation for machining free forms is an important phase. The modules of gouge removal are considered to be vital in any computer aided manufacturing (CAM) software. Instead of generating toolpaths and then searching interference positions, the process usually used, an approach is presented in which the surface is preprocessed in order to discard the zones of potential interference probability from the domain of definition of the surface. Afterwards, a simple sweeping process of the parametric space of the surface can generate interference-free toolpaths. This pre-processing approach has the advantage of eliminating interferences regardless of the orientation of the surface, and the chordal and scallop height tolerances for a given cutter. 相似文献
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Machining of free-form surfaces has an important role in industrial manufacturing, but conventional tool-path generation strategies for free-form surfaces machining have the drawbacks of serious flattening distortion and poor tool-path continuity. Therefore, a novel method is developed to generate a spiral tool path for the machining of free-form surfaces by improving surface-flattening distortion and tool-path continuity. First, physical shell mapping is presented to flatten a free-form surface into a plane, which takes stretching energy, bending energy, and global energy into account. Then, the spatial spiral polyline is rounded to generate a spiral path by proposing reverse-compensation optimisation. Therefore, the free-form surfaces can be quickly flattened with less distortion, remaining free of overlap, and can in addition be machined at high speed along a C2 continuous spiral tool path. Further, the flattening error, tool-path length, mean curvature, mean scallop-height error of the spiral path, machining time and surface roughness are obviously reduced. Finally, simulation results are given to show the effectiveness and feasibility of the presented strategy. 相似文献
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Electrochemical machining is a useful technique for characterizing the inner alloy structure of metallic coatings. In the
present study, hot-dip zinc galvanized coatings were fabricated and the microstructures were analyzed after exposing each
layer of the coatings by successive anodic machining steps. With this method, the surface after each successive machining
step would be free from any mechanical damage or segregation of the dissolution products over the machined surface. The characteristics
of the alloy layers and their influence on the behavior of the coatings were investigated under a specific exposure condition.
The corrosion performance of the iron-rich inner alloy layers was found to be better than that of the pure zinc top layer
as revealed during electrochemical characterization. This paper provides insight into the correlation between the protection
strength of the galvanic coating and the quantity of zinc in the coating. 相似文献
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设计了一种在精密加工操作中对操作人员及外界非正常颤抖信号进行检测并自动补偿的微型操作仪。仪器结构精巧,具有可拆卸及更换的加工探头,可满足不同精密加工的使用需求。基于经典PID闭环控制和边缘检测原理,采用激光干涉仪对精密加工位置信号进行检测,对干扰信号进行判断并做出相应补偿措施;采用压电陶瓷微电动机PM的逆向运动自动补偿颤抖产生的误差,保证精密加工的可靠性和精确度。实验表明,该微型仪器能自动补偿颤抖干扰信号,精度可达到1μm,对精密加工的精度提高及误差补偿研究有一定借鉴价值。 相似文献
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Process planning for the manufacture of free surfaces is mainly concerned with determination of machining configuration. In this paper, we investigate the machining configuration problem stated as: For a given surface model, find (1) The minimum number of control axes, (2) The minimum range of the rotational axes, and (3) The workpart setup orientation. In deriving the solution algorithm, we ensured implementability by casting the problem into an algebraic domain. Using a digitized visibility map, called the binary spherical map, the machining configuration problem can be solved in a unified fashion without falling into numerical complexity. The solution algorithms are implemented and validated via computer simulations, indicating they can be implemented on the CAD/CAM system as a process planner. 相似文献