Flexible Fixture Design for the Top and End Surface Processing of NP2_NP4 Cylinder Heads

This paper focuses on the design of fixtures for NP2 and NP4 cylinder heads on a horizontal machining center of flexible machining automatic lines.It began with an analysis of the diagrams of part processing and working procedure which formed the basis for the design of the processing technology scheme,a selection of suitable machine tools,and the setting of processing parameters.Fixtures tailored to the chosen machine tools were then designed to meet the processing requirements.Additional aspects of the project included the design of part drawings,calculation of working time quota,design of auxiliary guides,support clamping,and hydraulic circuits,all aimed at fulfilling practical production requirements.

Parametric Design of Modular Fixture Structure

Based on an example of its typical structure, the concept of modular fixture structure module is presented, and the structure module system of modular fixture is summarized. Then the parametric design of structure is discussed, and its advantages are also emphasized.Furthermore, some specific methods are provided, such as the selection of fixture components, the determination and input of parameters, drawing representative model,and the creation of drawing. Finally an applied example of strcture parametric design is presented.

Case-based Agile Fixture Design

In order to realize the agility of the fixture design, such as reconfigurability, rescalability and reusability, fixture structure is function unit based decomposed from a fire new point of view. Which makes it easy for agile fixture to be reconfigured and modified. Thereby, the base of case based agile fixture design system info is established.Whole case based agile fixture design model is presented. In which, three modules are added relative to the other models, including case matching of fixture planning module, conflict arbitration module and agile fixture case modify module. The three modules could solve the previous problem that the experience and result are difficult to be reused in the process of design.Two key techniques in the process of the agile fixture design, the evaluation of case similarity, and restriction based conflict arbitration, are listed. And some methods are presented to evaluate the similarity and clear up the conflict.

Modular Fixture Assembly Model for Virtual Assembly Design

To support modular fixture assembly design in virtual environment,a multi-view based modular fixture virtual assembly model is proposed.Instead of squeezing all assembly related information into a single model,three complementary views of assembly model,element information,function and structure,and assembly relationship are proposed to be used.The first view contains the detailed element information,while the other two explicitly capture the hierarchical function relationships and mating relationships respectively.These views are complementary in the sense that each view only contains a specific aspect of assembly related information while together they include required assembly related information.The proposed assembly model is specialized to accommodate the features of modular fixture virtual assembly design and applied in our developed prototype system.

Study on Case-Based Fixture Design

Fixture is an important manufacturing activity. A fixture design system based on case-based reasoning (CBR) is proposed in this paper. A new method of case representation on the basis of fixture function is presented, where the case representation is constituted of workpiece knowledge, processing feature knowledge, and fixture feature knowledge. Running the prototype system shows that the knowledge representation method, using cases, s a better way to transform and explain the design knowledge.

Development of the 3D-Designed Lathe Fixture of a Float Brake Caliper

According to the technique requests of the brake caliper in the process of production, a special fixture of float brake caliper has been developed based on 3 D design in this paper. The development process and verified data from 3D modeling and kinematics simulation for this special fixture show that this 3D-designed process can conveniently forecast the assembly interference of the fixture and accurately add the mass of lead brick before the prototype is made. In this way the flutter caused by the unbalanced lathe fixture can be eliminated and the precision of run-out tolerance in cylinder hole compared with machine tool spindle can be improved, thus the processing quality of the cylinder hole in a brake caliper can be greatly guaranteed.

Fixture Design to Supplement Machining and Fuel Cell Education

A vital part of enhancing the ability of students to learn about advanced fabrication techniques is identifying the barriers to the student’s entry and excelling in the manufacturing field. In the Manufacturing and Mechanical Technology fields, there exists an intimidating experience gap or barrier between professionals and novice students. The students’ participation in the design and fabrication of a fixture for manufacturing a mechanical part will aid in eliminating this barrier by making fuel cell’s bipolar plates production accessible to inexperienced technology students. The process of manufacturing a fixture for the production of hydrogen fuel cell and hydrogen purifier plates required a careful planning and step-by-step methodological implementation. Through the use of our designed fixture, it is now possible to teach students how to use a CNC milling machine with relative ease while also allowing for precision part machining. The setup of the fixture allows students to observe the necessary measures to properly machine a part while also teaching them the benefits of fixtures in the manufacturing industry. In summary, the purpose of this paper is to provide the students with applied learning experience through involving them in the design and fabrication of a multi-disciplinary mechanical fixture and the utilization of practice oriented teaching resources in a full scale learning environment.

Application of Genetic Algorithm in the Layout of Fixture Components

Automation in the layout of fixture components is important to achieve efficiency and flexibility in computer aided fixture design. Based on basic genetic algorithm and particulars of different fixture components, a method of layout space division is presented. Such techniques as suitable crossover rate, mutation rate and selection arithmetic element are adopted in the genetic operation. The results show that genetic algorithm can effectively be applied in the automatic layout of fixture components.

Research on CAD system of lever-hinge style welding fixture

A computer aided design system of welding fixture (called WFCAD system) is introduced in this paper. The microcomputer graphics software AutoCAD has been used as the supporting software of WFCAD system. By means of programming, 2-D and 3-D parameterized graphic libraries of components of welding fixture are established. With the aid of AutoCAD ' s advanced development system (ADS), menus and dialogs are constructed for convenient use of graphic library, and it also makes the system has a good man-machine interface.

Fixture Modifications for Effective Control of an Electrodynamic 3D-Shaker System

This work aims to improve the setup of an electrodynamic triaxial shaker prototype with respect to its usability for the automotive industry.Triaxial shakers being capable of meeting the corresponding requirements are not available as standard test equipment.Modifications on the fixture have to be conducted in order to ensure an effective control.The first part of the work is the qualitative description of the system behavior.Therefore,the shaker is treated as a black box.The second part is the modification of the test fixture in order to handle the resonances of the shaker,which is elementary for its usage.A setup is found,that improves testing within the desired frequency range.Thereby,acceleration levels are considered as well as excitation phases and coherences.The proposed setup is used for an exemplary specimen with two different control scenarios.Conclusions are then drawn about the usage of triaxial shakers.

Stability ofWorkpkce Setup in Feature-Based Fixture Planning System

Analyzed the issues of stability of workpiece during clamping and machining. Discussed classification of the stability problem according to the forces acting on the part in the commonly used machining processes; gave the methods of calculating clamping force and measures to guarantee the stability of workpiece in the feature-based fixture planning design system.

铝型材冷却初拉伸控制

针对铝型材加工过程中的拉伸夹具及冷却时间度量问题,设计适用于不同型号的拉伸夹具,确定了不同加工参数下的最佳冷却时间。通过优化拉伸夹具的设计和冷却时间的控制,能够提高铝型材的加工质量和生产效率。实验结果表明,该方法能够有效地改善铝型材的性能和形状,具有较高的应用价值。

基于模糊自适应PID控制器的夹具自适应控制研究

为提高夹具自适应控制的稳定性和响应速度,以电磁无心夹具为研究对象,提出一种基于模糊自适应比例-积分-微分(proportion integration differentiation, PID)控制器的控制方法。首先构建夹具数学模型,然后结合模糊控制和PID控制的优势,构建模糊自适应PID控制器对夹具进行自适应控制,最后通过在MATLAB软件上进行仿真。结果表明,该方法实现了阶跃信号、突加负载、正弦信号输入等不同条件下的夹具控制,且具有优异的控制性能。整个控制过程中,该方法超调量为2.11%,响应时间0.08 s。相较于PID控制器、模糊控制器、自抗扰控制器、模糊滑模控制器,该方法提高了夹具自适应控制的精度和响应速度,且可用于实际夹具自适应控制中,具有一定的实际应用价值。

车架纵梁焊接变形控制在生产线中运用

车架总成运用在皮卡、轻卡和非承载式乘用车上,是非常重要的底部骨架件。车架总成质量对整车安全、舒适性影响较大。车架总成中纵梁总成的焊接变形最难控制,传统的控制焊接变形方式已经很难保证纵梁总成变形量,使得车架整体尺寸控制和装配都难达到高品质要求,为了提升车架总成尺寸,降低车架纵梁总成焊接变形量,本文对车架纵梁总成焊后变形进行研究,从夹具设计和机器人焊接布局两方面来保证纵梁总成焊后变形控制在2.3-3.2mm,从而保证车架总成尺寸和生产效率。

数控加工机械零件中的专用夹具设计

科技快速发展背景下,数控技术以其诸多优势和特点,被广泛应用于机械零件生产中。不仅优化了传统机械零件设计精度和加工质量,也进一步推动了机械零件数控加工作业发展进程。专用夹具作为数控加工机械零件中的重要组成部分,合理设计专用夹具是实现精细加工的关键所在。主要围绕数控加工机械零件中专用夹具的设计问题进行了一系列讨论。先后概述了数控加工的概念、特点、基本流程以及基本原则,分析了数控加工机械零件中专用夹具设计要点和选择要点,进而以锁芯零件专用夹具设计为例进行了具体案例分析。

复合装甲剩余压缩强度测试夹具设计及仿真分析

为满足复合装甲测试的要求和考虑实验研究的成本问题,通过了解压缩试验的方法和测试剩余压缩强度的过程后建立夹具的结构形式,对夹具结构进行有限分析得到相关的仿真结果。分析结果说明,夹具可以用于测试剩余压缩强度的实验,并且满足成本低、加工方便、操作简单的设计要求。

箱盖加工工艺与钻孔专夹设计

根据钻箱盖零件6-Φ13.5通孔的特点及工厂的实际状况,该文设计了一种带分度装置、定位芯轴、能快速装拆工件的专用夹具。此夹具改变了以往采用传统分度装置或偏摆分度装置的装夹方式,可按照箱盖零件要求对其进行机械加工工艺设计,使其从铸造件成为合格的产品。其中,设计了第十道工艺步骤钻6-Φ13.5通孔,采用一圆一面定位,限制五个自由度,并利用弹簧压板、偏心手柄夹紧,然后利用弹簧对顶杆进行分度定位后进行加工。对比以往常用的此类夹具,该夹具能使钻孔所用的麻花钻刀长度有效减少,操作简单方便,节约了时间,提高了生产效率,可行性极高。

薄壁卷圆管自定心夹具结构优化设计

为满足不同直径、长度、厚度规格的圆筒类工件焊接过程中的装夹需要并减轻其夹具的质量。通过自定心夹具的结构设计及受力分析,建立夹具结构的有限元模型,并使用有限元分析获得夹具的静态特性。在此基础上利用尺寸优化的设计方法,对其进行了以减轻质量为目标的优化设计,最终完成了对V型夹具的轻量化设计。将优化后的V型夹具与优化前进行比较,结果显示:在夹具最大变形量小于0.5 mm且最大应力值小于156 MPa的情况下,单个V型块的质量由初始设计时的33.854 kg减小到了14.954 kg,减轻了55.83%。通过尺寸优化设计,减轻了夹具质量,提高了夹具的工作性能,该研究结果可对圆管直缝焊接设备的夹具相关研究提供参考。

一种可调节通用式板级振动夹具的设计与验证

本文设计了一种可调节通用式板级振动夹具,夹具能够以无损拆装的方式,对PCB样品的边孔或板内任意位置进行固定,从而使振动试验过程中,样品的安装固定方式能够更加贴近真实的装机状态,提高振动试验的有效性。同时,开展了对夹具的验证试验,结果显示本套通用夹具不仅自身具有良好的振动响应,而且能够对样品板内无预留安装孔的位置进行有效地固定,使样品上的振动响应接近振动台设置值。这说明本套通用夹具在兼容不同尺寸样品的同时,能够有效避免过试验或欠试验的发生,提高振动试验的准确性。

系外行星成像星冕仪振动夹具设计与试验分析

为设计满足巡天空间望远镜系外行星成像星冕仪振动试验要求的夹具,对初步设计的振动夹具进行模态仿真分析。根据分析结果,识别夹具薄弱环节,并对振动夹具进行改进设计。通过分析计算,改进后的夹具满足设计固有频率要求。并对其进行正弦振动和随机振动动力学分析。将夹具在振动台上进行正弦扫频试验,验证设计合理性。夹具的仿真一阶模态结果342.6Hz,其振动试验结果一阶模态为329Hz。振动夹具一阶固有频率的试验结果与仿真计算误差约为4%,误差合理。试验验证了仿真计算结果的正确性。实现了振动夹具的基频大于试验件3倍的目标,振动夹具设计合理。满足巡天空间望远镜系外行星成像星冕仪力学环境试验使用。