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加工连杆过程中,对两孔轴线平行度的检验至关重要,它将直接影响连杆的装配精度和使用性能。为此,依据零件图样标注,应优先使用位置量规检验平行度,以迅速、准确地判断连杆小端孔的尺寸误差和位置误差综合作用的结果,保证连杆装配时的互换性。本文详细介绍连杆位置精度检验量规的设计。 相似文献
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6-SPS机构位姿矩阵采用四元数法描述,并将该矩阵和矢量坐标扩展为4维形式,推导出无间隙机构的运动方程,得到了机构运动的新型雅克比矩阵J_A和J_B;在此基础上,利用连续接触模型得到了两个含间隙S副共连杆和异杆时机构的运动系数矩阵。分别把各个运动系数的行列式展开,得到含间隙机构第一类奇异和第二类奇异的轨迹方程,利用MATLAB得到了机构在给定位置时的第一类位姿奇异轨迹和第二类位姿奇异三维轨迹曲面;通过将两类含间隙机构奇异轨迹曲面的比较,发现机构间隙对第二类奇异的影响大于对第一类奇异的影响;在两类奇异轨迹中,当S副异杆时,机构间隙的影响均大于S副共连杆时的影响。以无间隙机构奇异轨迹曲面上奇异点作为参考点,通过含间隙机构奇异轨迹曲面上与参考点相对应奇异点的相互比较,发现存在一个关于参考点的奇异域。 相似文献
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工序尺寸在标注时工序基准的选择及定位基准的选择一般要遵循与设计尺寸重合的原则;不过,有时为了便于测量或装夹稳妥等因素,也可以不遵循这样的原则。定位误差是工件装夹时由于定位方式的原因而产生的工件相对于机床或刀具的相对位置误差,工序尺寸的不同标注方式对定位误差会产生比较大的影响,从而影响到零件的加工精度。 相似文献
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针对双三角并联机器人的特点,采用位置反解直接求导的方法,建立了包括全部结构参数误差和主轴端位姿的精度综合模型.引入影响因子加权法完成了并联机器人位姿的精度综合.并结合实例给出了综合后所获得的各铰链点及杆长的公差值,为此类并联机器人结构的精度设计提供了一条有效的途径. 相似文献
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《中国新技术新产品》2017,(14)
本文主要介绍一种卧式加工中心机床的同步双驱双主轴结构,用于汽车发动机关键零部件连杆的大、小头孔半精镗,精镗的加工。汽车行业作为我国迅猛发展产业之一,其中汽车内燃机核心零部件的加工是汽车行业发展的重要课题,连杆作为内燃机核心零件之一,也是加工精度较高的零件之一。作为大批量生产的汽车连杆零件由于受到成本、效益的制约,如何在保证加工精度的同时又能极大地提高加工效率,创造更大的经济效益成为摆在汽车发动机连杆加工专用机床面前的难题。 相似文献
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机床的质量取决于机床关键部件的质量,而机床主轴部件是保证机床加工精度的核心,主轴回转误差是影响机床加工精度的重要因素之一,直接影响到加工零件的形状精度、表面的粗糙程度和质量,实验结果表明:由主轴回转误差引起的精密 相似文献
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零件面形精度满足要求是超精密装备实现其关键功能的重要保证.影响工件加工面形精度的因素很多,机床体误差是其中最关键的因素.通过构建机床误差元与加工面形误差之间的直接关系来进行面形误差预测研究.提出了一种基于机床体误差模型的频域多尺度面形误差预测方法,该方法可结合机床体误差模型、工艺参数、加工轨迹等进行频域多尺度面形误差预测,可为加工路径规划、机床设计等提供理论参考,从而提高加工精度.进行了低频PV面形误差预测的实例研究,采用的机床为一台五轴联动超精密机床,加工表面为凹形截圆锥台锥面.通过实验与理论分别获得PV面形误差,其相对误差为17.3%,证明基于机床体误差模型的低频PV面形误差预测是可行的. 相似文献
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Diamond turning technology has gained great importance in high-precision optical component fabrication. The quality of machined optical surfaces is mainly affected by the machine tool's accuracy, cutting tool's quality, and dynamic machining effects. This study investigated the effects of cutting tool conditions and tool set-up error on the surface distortion. Controlled cutting tests were performed on a two-axis diamond turning machine. Spherical mirrors with preset tool offset values and tool height values were turned. The relationship among machined form accuracy, tool offset, and tool height was investigated based on experimental and analytical results. The influence of tool wear on machined surface quality was studied. Factors governing uneven wear along the cutting edge in contour machining were analyzed. A spherical surface with a form accuracy better than λ/10 was produced. Methods for minimizing the effect of tool wear are also discussed. 相似文献
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为了实现非球面模具的超精密数控加工,研究了加工轨迹算法原理及整个软件系统的结构与实现.提出了基于表面粗糙度均匀化的工件进给速度控制法,分析了工具磨损误差和工件形状误差,重点提出了误差补偿方法,同时也讨论了采用砂轮平行磨削法时避免加工干涉的方法.软件能生成高精度的加工与补偿加工数控程序文件.最后,在一台镜面磨床上实验加工直径为6 mm的碳化钨透镜模具,经过多次补偿加工后,获得了谷峰值为0.123μm,误差均方根为0.021μm的表面形状精度. 相似文献
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Free-form surfaces are widely used in many applications in today’s industry. This paper presents a new approach to identify and compensate process-related errors in machining of free-form surfaces. The process-related errors are identified online by a newly developed in-process inspection technique. In this technique, the surface is first machined through an intermediate semi-finishing process that is specifically designed to machine different geometric shapes on the surface with different process parameters. An inspection method is developed to identify the process-related errors in the selected regions on the semi-finished surface. The relationship between the machining/surface parameters and process-related error is then achieved using a neural network. This relationship is used to predict the process-related errors in the finishing process. The process-related errors, together with the machine tool geometric errors identified using a method developed in our previous work, are compensated in the finishing tool paths through tool path re-planning. Experiment has been conducted to machine a part with a free-form surface to show the improvements in the machining accuracy. 相似文献
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超精密磨削大型光学非球面元件的研究 总被引:1,自引:0,他引:1
介绍了加工大型光学非球面的超精密数控磨削系统,给出了用来生成NC加工软件的加工非球面时砂轮的中心位置的求解模型,在此基础上讨论并给出了由砂轮安装产生的砂轮与工件主轴的偏心误差形成的加工工件面形误差的计算模型,并提出有效的工具路径补偿方法。通过计算机模拟验证了这种补偿方法的可靠性。 相似文献
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刀具对中误差对离轴抛物面镜慢刀伺服车削加工的影响 总被引:1,自引:0,他引:1
离轴抛物面镜单件高效加工是离轴三反消像散(TMA)结构光学系统的技术难点之一.单点金刚石慢刀伺服车削加工技术可用于离轴非球面加工,加工尺寸范围较大,加工精度较高.此工艺制造的离轴抛物面面型精度可达到亚微米级,粗糙度达到纳米级.因此,可直接用于红外光学应用,若经后续抛光则可用于空间望远镜等更高精度需求的场合.介绍了慢刀伺服车削加工离轴抛物面镜的在轴加工方法,理论推导了刀具对中误差所带来的面形误差的极值分布规律.仿真研究进一步揭示了工件中心区域面形误差的详细分布.实验数据与理论结果和仿真计算结果均吻合. 相似文献
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Dan Zhang Xiaoping Su Zhen Gao Jijie Qian 《International Journal of Mechanics and Materials in Design》2013,9(3):199-212
Most of the existing parallel robotic manipulators have coupled motion between the position and orientation of the end-effector. The complexity of the multi-axial manipulation produces the difficulty to control. This research deals with a lower mobility parallel manipulator with fully decoupled motions. The proposed parallel manipulator has three degrees of freedom and can be utilized for parts assembly and light machining tasks that require large workspace, high dexterity, high loading capacity, and considerable stiffness. The manipulator consists of a moving platform that is connected to a fixed base by three pairwise orthogonal legs which are comprised of one cylinder, one revolute and one universal joint respectively. The mobility of the manipulator and structure of the inactive joint are analyzed. Kinematics of the manipulator including inverse and forward kinematics, velocity equation, kinematic singularities, and stiffness are studied. The workspace of the parallel manipulator is examined. A design optimization is conducted with the prescribed workspace. It has been found that due to the special arrangement of the legs and joints, this parallel manipulator possesses fully isotropic. This advantage has great potential for machine tools and coordinate measuring machine. The experiment on the prototype verifies its feasibility as a portable parallel robotic machine tool. 相似文献