柔性夹具技术研究

为适应快速多变的市场需求,制造企业需要设计并应用柔性夹具。介绍了柔性夹具的发展及特点,给出了柔性夹具的设计依据,并从零件结构及工艺、组成元件确定、强度与精度保证等方面分析了柔性夹具的设计方法。     

汽车主模型ABS轻量化后地板检测模块的设计制造研究

后地板检测模块在燃油车与电动车内饰切换时拆卸频繁,为操作方便,需将后地板模块轻量化。而传统铝制模块密度大,质量易超标,因此,有必要采用轻量化材料如丙烯腈-丁二烯-苯乙烯共聚物(ABS)塑料来制备后地板检测模块。ABS材料密度小,成本低,但硬度低,强度弱,表面光洁度差。为解决这些问题,采用铝制骨架与ABS模块喷漆相结合的设计方式,通过设计阶段的强度计算,确定了质量轻、强度与表面质量均满足要求的后地板检测模块的设计方法。     

MTConnect compliant monitoring for finishing assembly interfaces of large-scale components: A vertical tail section application

Monitoring is a significant issue for finishing the assembly interfaces of large-scale components before final assembly. Acquisition and supervision of the pivotal data is essential to ensure the security and reliability for machining the large and complicated components with high-value. This process is generally cumbersome and time-consuming because there are various types of data coming from different components and sensors. The problem becomes more serious when considering the whole shop floor. Recently, MTConnect has been proven to be an effective method to realize standardized data collection and monitoring process. However, MTConnect is still under development and cannot cover the whole finishing process such as on-machining measuring (OMM) and fixturing. To address the issue, an MTConnect compliant method with extended data models is proposed in this paper to implement a standardized monitoring system. Firstly, a finishing system for the assembly interfaces is introduced, including the framework, workflow and key procedures and data. Then extended MTConnect data models are proposed to represent the finishing system including on-machine touch-trigger probe and sensor-based intelligent fixturing related information. Based on the extended MTConnect data models, a web-based monitoring system is developed for data collection and monitoring by combining an MTConnect agent and an OPC adapter. The proposed approach is validated by collecting and monitoring the key process data using an airplane vertical tail as an application. The advantages of using MTConnect would be more significant when extended to the entire factory and implemented in cloud manufacturing in the future.     

高速高精度连杆精镗机床的设计

摩托车连杆大端孔的精加工是连杆加工中的重要工序,通过对连杆加工前状况的分析和本序加工后要达到的各项精度进行分析,设计卧式双轴精镗床,保证了节拍28s/两件,圆度0.01 μm,孔的粗糙度达到Ra0.8,重点对机床的总体结构、机床的刀具、机床的镗头、工件在夹具上的定位、夹具上的让刀机构、机床的工作循环等进行分析,这对研制同类型的高精度的镗床具有一定的参考价值.     

钼炉耙臂装卸夹具的建模与应力分析

在SolidWorks软件平台上建立钼炉耙臂装卸夹具的三维模型,对夹具结构进行设计分析,检验其合理性。同时对所建零件模型进行虚拟装配,然后对装配模型进行三维动态检查。Solid-Works软件的使用提高了夹具的设计效率,也提高了其设计质量。     

基于UG的组合机床夹具智能设计系统的研究与应用

介绍了组合机床夹具设计的研究状况,分析了企业开发应用组合机床夹具智能设计系统的必要性及该系统实现存在的难点。在分析构建该智能设计系统的系统框架的基础之上,利用三维设计软件UG的OPEN二次开发功能及其WAVE技术的相结合,开发实现了该系统,并对实现该系统的关键技术进行了详细的阐述,主要包括夹具知识库的建立及夹具体等非标准灵活性零件的设计过程等。最后进行了工程应用,结果表明该系统能提高组合机床夹具设计的效率和质量。     

一种高压潜污水泵自动耦合系统设计

针对当前潜污水泵自动耦合安装系统大多只能实现50 m扬程以下使用场合的现状,提出并设计了一种高压潜污水泵自动耦合系统。根据系统安装的要求,确定了安装方式,设计了该系统的机械结构,完成了液压系统和液压夹具的设计。采用PLC触摸屏一体机,实现高压潜污水泵的自动耦合控制和相关数据采集及显示。通过试验,证明了该系统能够完成高压使用场合的潜污水泵自动耦合安装。     

A geometric approach to automated fixture layout design

Fixtures are used in many manufacturing processes to hold objects. Fixture layout design is to arrange fixturing elements (fixels) on the object surface such that the object can be held in form-closure and totally immobilized. It is well known that 4/7 fixels are sufficient for immobilizing a 2D/3D object without rotational symmetry and their locations satisfy form-closure if and only if the convex hull of their primitive wrenches forms a 3D/6D simplex in the wrench space containing the origin as an interior point. This paper presents a method for finding form-closure locations of 4/7 fixels with enhanced immobilization capability. First, the Gilbert-Johnson-Keerthi distance algorithm and the Gram-Schmidt process are used to yield the fixel locations such that the simplex with vertices at their primitive wrenches is 3D/6D and contains the origin. Then, an interchange algorithm is developed for altering the fixel locations to meet form-closure and increase an immobilization capability index of fixture layouts. The meanings of this index in fixture localization accuracy and force balance capability are elucidated as well. Its value is proved to be equal to the minimum distance from the wrench origin to the facets of the wrench simplex in terms of a unit-invariant norm for wrench vectors. Without using any general optimization techniques, this method determines an optimal fixture layout very efficiently, so that it can be tried with various initial conditions to attain a result approaching the global optimum or with other good performance qualities.     

面向并行工程的计算机辅助夹具设计系统研究

在传统的产品制造过程中，夹具设计与准备需要占用较长的时间，并且质量不能保证，导致返工，成为产品开发中的一个“瓶颈”。本文提出基于并行产品开发环境的计算机辅助夹具设计的系统结构模型，并且对该结构模型的实现方法作出了详尽的阐述。依据该结构模型，作者研究开发了ＣＥ－ＣＡＦＤ系统。应用验证表明，该系统能够较好地解决夹具设计这一“瓶颈”，有效缩短了产品开发周期，并且产生了一定的经济效益。     

Improvement of flatness error in milling plate-shaped workpiece by application of side-clamping force

To improve flatness error of plate-shaped workpieces in milling under side clamp holding mechanisms, appropriate magnitudes of clamping forces and method of application are studied in this paper. The effect of side-clamping force on workpiece deformation is investigated by experimental and computational analyses for the case where the workpiece is clamped at a position higher than the neutral plane of bending of the plate-shaped workpiece. It is found that the thermal deformation and elastic deformation caused by clamping force are in two opposite directions. Then, an appropriate method is proposed to compensate for the workpiece thermal deformation caused by cutting heat with the opposite elastic deformation caused by the side-clamping force, so as to keep the machined top surface of the workpiece flat as much as possible. The proposed method has been confirmed through computational analyses and experiments. © 2000 Elsevier Science Inc. All rights reserved.