共查询到18条相似文献,搜索用时 140 毫秒
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夹具原始概念模型的创建方法研究 总被引:2,自引:1,他引:1
夹具概念设计是夹具设计自动化必不可少的一个阶段 ,是当前较少涉及的一个问题。对此 ,本文首先介绍了面向概念设计和创新的功能表面、广义定位原理和广义定位模式的概念 ,然后提出了夹具原始概念模型的概念。在其基础上 ,选择实现工件广义定位的定位模式 ,通过提取三维信息和生成相应的功能表面来创成夹具的原始概念模型。文中最后给了一个实例。该项工作是夹具结构进化设计的基础。 相似文献
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夹具定位原理在产品设计自动化中的应用 总被引:5,自引:0,他引:5
为了解决产品设计自动化的问题,在分析用于夹具设计的六点定位原理的基础上,提出了广义定位原理。基于广义定位原理及分解重构等理论,构造了产品自动化设计理论模型,并进行了软件系统的实现。 相似文献
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表面形状为自由曲面零件的装夹设计研究 总被引:5,自引:0,他引:5
表面形状为自由曲面零件的夹具设计是机械制造领域中的一个难点问题。但是,该类夹具的设计尚未引起广大夹具设计人员的充分注意,成功的设计范例也为数不多,这一现实已不能满足日益增长的自由曲面零件加工制造的要求。本文结合863/CIMS关键技术攻关项目“面向并行工程的计算机辅助夹具设计”的实践并加以扩展,重点讨论了该类夹具设计领域的零件装夹这一难点问题,并根据确定性定位理论与曲面理论给出了自由曲面零件上定位点的选取算法与夹紧点选取策略。 相似文献
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欧龙 《机械工人(冷加工)》2009,(2):40-41
我公司是一个OEM零件生产厂,产品以铝合金压铸件为主,开发流程从压铸模具的设计制造到压铸成形、机械加工、表面处理全过程。零件在加工中心加工过程中,常出现一批合格,一批不合格的现象,经过多方面分析,主要原因出现在机加夹具设计上,在机加夹具设计中,没有考虑到零件压铸成形的特点,定位基准选择不合理,从而造成加工尺寸不稳定。下面就以我公司加工中心使用夹具来探讨压铸件夹具设计方法。 相似文献
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陈启银 《机电产品开发与创新》2003,(6):47-49
针对集装箱箱角的生产现状,提出了以箱角内表面作粗基准的加工工艺,同时设计了铣削加工的气动夹具,为了提高内表面定位的稳定性和安装刚性,设计了结构新颖的四点联动夹紧的浮动支承。 相似文献
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刘玉春 《机械工人(冷加工)》2005,(12):71-72
定位误差的分析和计算一直是夹具设计人员感到厌烦而又不得不进行的一项工作。特别是在定位误差与相关变量的关系是非线性且为多元函数的情况下,误差计算公式的推导过程极为繁琐,有时会使设计人员感到束手无策。在工程实践中,也有因公式推导和计算出错而导致夹具制造出来后不能满足使用要求,造成极大浪费和损失的情况。为此,我们利用AutoCAD绘图软件的测量功能或编写简单AutoLISP程序,可以直接或间接地测量其定位误差,从而替代定位误差的手工计算,避免由此可能产生的错误。这里以双偏心轮式V形定位夹具为例,介绍在AutoCAD软件环境下直接或间接测量V形定位夹具定位误差的方法和技巧。 相似文献
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G.H. Qin W.H. Zhang M. Wan G.H. Qin 《The International Journal of Advanced Manufacturing Technology》2006,29(3-4):349-359
In manufacturing engineering, localization accuracy is a key concern in the design of a fixture to specify a locating scheme
and tolerance allocation. This paper presents a general analysis methodology that is able to characterize the effects of localization
source errors based on the position and orientation of the workpiece. From this methodology, a fixture model is formulated
by taking into account the overall errors among the system consisting of the workpiece and the fixture in the design of the
fixture locating scheme. With this model, the locating principle and a criterion of the robust optimal design are then proposed
to improve the localization quality of the fixture. Some examples are provided and allow for a detailed discussion about how
to carry out the optimal design of the locating scheme. A comparative study is also made between the optimal solution and
the empirical one. Finally, an experiment is made to validate the fixture locating scheme for a cylindrical workpiece. We
conclude that this robust design method effectively achieves stable machining precision in workpieces. 相似文献
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基于运动学方法的线性尺寸定位误差通用建模与分析 总被引:2,自引:0,他引:2
定位误差是评价夹具性能的重要指标 ,分析定位误差是夹具设计中的一个重要环节。由于定位元件与工件的制造误差 ,工件安装后将不可避免地产生位置偏移 ,定位误差就是由于工件上的工序基准点位置在加工方向上发生偏移而引起的。现有夹具定位方案误差分析方法 ,如合成法、极限位置法以及微分法所建立的定位误差计算模型仅适用于特定类型的定位方案 ,不具备通用性 ;而目前利用运动学方法所建立的夹具模型仅考虑了定位接触点位置的影响 ,没有考虑调刀基准点位置偏移的影响。为此 ,根据运动学方法 ,在完善夹具模型的基础上 ,本文提出线性尺寸定位误差的通用模型与分析技术。 相似文献
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Machining fixture layout design using ant colony algorithm based continuous optimization method 总被引:3,自引:2,他引:1
K. P. Padmanaban K. P. Arulshri G. Prabhakaran 《The International Journal of Advanced Manufacturing Technology》2009,45(9-10):922-934
In any machining fixture, the workpiece elastic deformation caused during machining influences the dimensional and form errors of the workpiece. Placing each locator and clamp in an optimal place can minimize the elastic deformation of the workpiece, which in turn minimizes the dimensional and form errors of the workpiece. Design of fixture configuration (layout) is a procedure to establish the workpiece–fixture contact through optimal positioning of clamping and locating elements. In this paper, an ant colony algorithm (ACA) based discrete and continuous optimization methods are applied for optimizing the machining fixture layout so that the workpiece elastic deformation is minimized. The finite element method (FEM) is used for determining the dynamic response of the workpiece caused due to machining and clamping forces. The dynamic response of the workpiece is simulated for all ACA runs. This paper proves that the ACA-based continuous fixture layout optimization method exhibits the better results than that of ACA-based discrete fixture layout optimization method. 相似文献
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Development of a finite element analysis tool for fixture design integrity verification and optimisation 总被引:2,自引:1,他引:2
Nicholas Amaral Joseph J. Rencis Yiming Rong 《The International Journal of Advanced Manufacturing Technology》2005,25(5-6):409-419
Machining fixtures are used to locate and constrain a workpiece during a machining operation. To ensure that the workpiece is manufactured according to specified dimensions and tolerances, it must be appropriately located and clamped. Minimising workpiece and fixture tooling deflections due to clamping and cutting forces in machining is critical to machining accuracy. An ideal fixture design maximises locating accuracy and workpiece stability, while minimising displacements.The purpose of this research is to develop a method for modelling workpiece boundary conditions and applied loads during a machining process, analyse modular fixture tool contact area deformation and optimise support locations, using finite element analysis (FEA). The workpiece boundary conditions are defined by locators and clamps. The locators are placed in a 3-2-1 fixture configuration, constraining all degrees of freedom of the workpiece and are modelled using linear spring-gap elements. The clamps are modelled as point loads. The workpiece is loaded to model cutting forces during drilling and milling machining operations. Fixture design integrity is verified. ANSYS parametric design language code is used to develop an algorithm to automatically optimise fixture support and clamp locations, and clamping forces, to minimise workpiece deformation, subsequently increasing machining accuracy. By implementing FEA in a computer-aided-fixture-design environment, unnecessary and uneconomical “trial and error” experimentation on the shop floor is eliminated. 相似文献
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基于ABAQUS的弱刚度结构件装夹布局优化技术 总被引:1,自引:0,他引:1
装夹布局是弱刚度结构件加工变形的重要影响因素。以减小工件装夹的最大弹性变形量为目标,利用ABAQUS建立了弱刚度结构件的铣削加工装夹布局模型,并对各装夹方案进行了模拟分析,得出了最终的优化布局方案,采用该方案在加工过程中可以得到更低的变形量,变形分布更均匀。所提方法可应用于类似工件的夹具设计。 相似文献