质量功能配置在车身检具设计中的应用

针对汽车车身制造装备中典型的检具设计,提出了一种产品设计过程的质量控制策略.通过某车型后保险杠的检具设计实例,阐述了质量功能配置在车身检具设计过程中的应用方法和主要步骤.最后,建立了检具产品规划、零部件配置及工艺和生产规划质量屋的基本模型.应用结果表明,质量功能配置能有效控制产品开发的进度、质量和成本,并为单件、小批量制造模式的产品设计质量控制提供参考.     

汽车车身整车主模型检具的研究与开发

汽车车身整车主模型检具是专门用来验证汽车车身制造精度的1种特殊检测装备,它既要匹配整个车身,又要匹配各个零部件,是主机厂用来控制车身质量不可或缺的工装,但是,它结构非常复杂,零部件繁多,其中有许多活动件需要经常装拆,制造精度要求也特别高,它是机械行业中的高端产品,开发难度相当大。以某轿车车身主模型检具为例,详细阐述它的设计难点、设计步骤和设计要点等,为同类产品开发提供一定的工程参考作用。     

汽车车身门盖检具构思图设计方法

以机盖总成检具为例,从门盖检具通用结构、定位设置、间隙面差检测设置、内板型面检测设置、孔位检测设置等方面介绍设计汽车车身门盖检具构思图时采用的一般方法,为门盖检具设计提供依据。     

多款混合动力轿车车身后地板总成模块化拓展

提出了在燃油动力三厢轿车白车身后地板总成基础上进行模块化拓展,拓展后可同时用于HEV,PHEV及REEV三种新能源混合动力车型。基于拓展后的成果,HEV,PHEV及REEV可以根据对后地板总成的不同需求,选择不同的模块与组合,从而使后地板总成实现通用化及模块化,大幅节约了开发周期及模、夹、检具成本。定义了通用化及模块化的总成和零件,以及在何种车型上使用何种模块。     

车身检具热变形的数值仿真与结构优化研究

汽车覆盖件制造中多采用专用检测夹具作为主要检测手段，用于控制工序间产品质量。覆盖件检具对精度要求高，受使用环境温度影响产生的热变形不能忽略。针对某车型后门总成检具设计，运用有限元方法对检具热变形进行数值仿真，并将其与优化技术相结合应用到结构优化中，有效地降低了检具热变形。     

用UG软件设计汽车检具及工件关键形面的处理

检具在大批量生产中，被广泛地用于零部件的工序间的测量和最终检查，尤其在汽车行业被广泛应用，国内重要的小型冲压件一般都采用专用的检具作为主要的检测手段，一些汽车工业高度自动化的发达国家，都已采用在线检测设备，高效快速地反应产品质量问题。由于在线检测设备的成本和技术要求很高，在我国很难普遍地应用于小型车身冲压件的检测。因此车身覆盖件检具在国内汽车行业的应用已相当广泛，制造检测精度高的专用检具，成为许多汽车生产厂家亟待解决的问题。     

TAC的形式作用及与零件检具的差异

整车尺寸匹配分析工具TAC(以下称为车身主模型),根据不同的使用要求、作用和制造成本,所制定的形式也不同。文中从质量问题前四钻分析方法对车身主模型和零件检具的作用进行剖析,以便对车身主模型、零件检具的使用性质和作用有新的共识。     

汽车冲压件检验夹具的计算机辅助制造

汽车冲压件检验夹具是对汽车冲压零件的形状、轮廓、孔位尺寸等进行准确和高效检测的专用综合检测工具,是提高冲压件、冲压组合焊装件及整体车身质量必不可少的最佳检测方法。汽车冲压件检验夹具的计算机辅助制造技术近年来大量采用,它打破了传统翻制检具的工艺方法,使检具在质量上有很大提高,缩短了制造的周期,降低了工人的劳动     

汽车车身冲压件检具的设计开发

阐述了检具的基本构成及其检测原理,结合应用实例提出了汽车车身冲压件检具设计开发的一般方案及各功能部件的设计方法和相关要求,为检具的设计开发提供了参考依据,对于其它零部件检具的设计也有一定的参考价值。     

机器人视觉系统在焊装车间自动上件应用

各大车企焊装车间内,车身零件分总成的上件主要还是采用效率低下的人工上件方式,为解决零件分总成外购件无法保证输送料框精度问题,通过视觉系统与机器人结合自动识别上件方式,直接从精度较差料框中自动抓取零件上线,分总成零件上件自动化率提升效果显著,为焊装车间智能制造水平提升探索提供了实践方向。     

基于NSGA-Ⅱ算法的车身薄板零件公差优化

在汽车制造工业产品开发过程中,需要同时考虑质量与成本之间的矛盾。盲目提高质量要求,将使产品制造成本增加;随意降低成本,则有可能影响质量,导致客户投诉和返修率上升。首先建立概念设计阶段的装配偏差分析模型,用来分析车身装配质量;并选取指数函数作为公差成本函数,以此为基础建立多目标优化模型,然后采用NSGA-II算法优化各个零件的公差。最后利用车身侧围框架案例阐述零件公差分配过程,获得了多目标函数的Pareto解集,取得了较好的优化效果。     

Multi-objective optimization for optimum tolerance synthesis with process and machine selection using a genetic algorithm

This paper presents a new approach to the tolerance synthesis of the component parts of assemblies by simultaneously optimizing three manufacturing parameters: manufacturing cost, including tolerance cost and quality loss cost; machining time; and machine overhead/idle time cost. A methodology has been developed using the genetic algorithm technique to solve this multi-objective optimization problem. The effectiveness of the proposed methodology has been demonstrated by solving a wheel mounting assembly problem consisting of five components, two subassemblies, two critical dimensions, two functional tolerances, and eight operations. Significant cost saving can be achieved by employing this methodology.     

粒子群算法在装配顺序规划中的应用

装配顺序规划是计算机辅助工艺设计的一个重要环节,影响着轿车车身的装配质量和效率.针对当前装配顺序规划易产生组合爆炸等问题,提出了基于粒子群算法的装配顺序规划算法.装配偏差是影响装配质量的重要因素,因此应用装配体的装配偏差评价装配顺序.在装配顺序规划过程中,首先将装配顺序编码为粒子,根据所建立的判断规则进行识别粒子的可行性,并通过装配偏差评估可行粒子的适应度值,然后根据粒子群算法过程规划装配顺序,最后采用前翼子板案例阐述装配顺序的生成和优化过程.     

Principle of elastic averaging for rapid precision design

Elastic averaging has worked well throughout history to help create precision machines. With the advent of rapid fabrication processes such as additive manufacturing, abrasive waterjet machining, and laser cutting etc., parts fabricated from these processes can be designed with special elastic features that “average out” the uncertainty in dimension tolerances and manufacturing errors as a collective system at very low cost. This paper presents the principle of elastic averaging and explores simple flexure design to create elastic averaging features within parts for precision alignment and assembly applications. A first-order analytical model and a quick estimation approach is introduced to predict the alignment errors and the repeatability of these parts. Experimental results show that a part with four elastic averaging features was capable of achieving precision assembly with another mating part even after huge errors were purposefully introduced to the mating features. Results also show that the part can achieve sub-micron level repeatability after more than 20 trials of removals and assemblies. Lastly, analytical simulations show that repeatability of the part can be further improved by increasing the number of elastic contacts. All these results suggest that the assemblies of rapid fabricated parts with elastic averaging features can be as precise as those made from conventional machine centers.     

车身装配虚拟样机建模研究

传统的车身装配设计需要多轮实物试制,增加了周期和费用,为此提出了支持虚拟样机技术的车身装配集成建模框架。该集成框架分为基于焊装特征的装配建模、偏差传递计算模型和装配环境仿真模型等三个子模型,并以产品数据管理为平台,通过接口方式实现了各子模型中装配数据和过程信息的协调管理。最后给出了一个某实际车身前地板装配设计的实例。初步实践认为,该集成框架可对缩短装配开发周期、降低车身试制费用提供有效支持。     

Optimum manufacturing tolerance to selective assembly technique for different assembly specifications by using genetic algorithm

Tolerance on parts dimension plays a vital role as the quality of the product depends on sub components tolerance. Thus, precision products that are manufactured reflect at high manufacturing cost. To overcome this situation, sub components of an assembly may be manufactured with wider tolerance, measured (using latest technologies like image processing) and grouped in partition and corresponding group components may be mated randomly. This present work is to obtain an optimum manufacturing tolerance to selective assembly technique using GA and to obtain maximum number of closer assembly specification products from wider tolerance sub components. A two components product (fan shaft assembly) is considered as an example problem, in which the subcomponents are manufactured with wide tolerance and partitioned into three to ten groups. A combination of best groups is obtained for the various assembly specifications with different manufacturing tolerances. The proposed method resulted nearly 965 assemblies produced out of one thousand parts with 15.86% of savings in manufacturing cost.     

Time-Based Competition in Multistage Manufacturing: Stream-of-Variation Analysis (SOVA) Methodology—Review

Frequency of model change and the vast amounts of time and cost required to make a changeover, also called time-based competition, has become a characteristic feature of modern manufacturing and new product development in automotive, aerospace, and other industries. This paper discusses the concept of time-based competition in manufacturing and design based on a review of on-going research related to stream-of-variation (SOVA or SoV) methodology. The SOVA methodology focuses on the development of modeling, analysis, and control of dimensional variation in complex multistage assembly processes (MAP) such as the automotive, aerospace, appliance, and electronics industries. The presented methodology can help in eliminating costly trial-and-error fine-tuning of new-product assembly processes attributable to unforeseen dimensional errors throughout the assembly process from design through ramp-up and production. Implemented during the product design phase, the method will produce math-based predictions of potential downstream assembly problems, based on evaluations of the design and a large array of process variables. By integrating product and process design in a pre-production simulation, SOVA can head off individual assembly errors that contribute to an accumulating set of dimensional variations, which ultimately result in out-of-tolerance parts and products. Once in the ramp-up stage of production, SOVA will be able to compare predicted misalignments with actual measurements to determine the degree of mismatch in the assemblies, diagnose the root causes of errors, isolate the sources from other assembly steps, and then, on the basis of the SOVA model and product measurements, recommend solutions.     

Optimal tolerance design of assembly for minimum quality loss and manufacturing cost using metaheuristic algorithms

Tolerance allocation is a design tool for reducing overall cost of manufacturing while meeting target levels for quality. An important consideration in product design is the assignment of design and manufacturing tolerances to individual component dimensions so that the product can be produced economically and functions properly. The allocation of tolerances among the components of a mechanical assembly can significantly affect the resulting manufacturing costs. In this work, the tolerance allocation problem is formulated as a non-linear integer model by considering both the manufacturing cost of each component by alternate processes and the quality loss of assemblies so as to minimise the manufacturing cost. Metaheuristics techniques such as genetic algorithm and particle swarm optimisation are used to solve the model and obtain the global optimal solution for tolerance design. An example for illustrating the optimisation model and the solution procedure is provided. Results are compared with conventional technique and the performances are analysed.     

An investigation into design and manufacturing of mechanical conveyors systems for food processing

This paper presents the results of a research investigation undertaken to develop methodologies and techniques that will reduce the cost and time of the design, manufacturing and assembly of mechanical conveyor systems used in the food and beverage industry. The improved methodology for design and production of conveyor components is based on the minimisation of materials, parts and costs, using the rules of design for manufacture and design for assembly. Results obtained on a test conveyor system verify the benefits of using the improved techniques. The overall material cost was reduced by 19% and the overall assembly cost was reduced by 20% compared to conventional methods.     

An automated assembly environment in feature-based design

In the integration of design and manufacturing, one of the primary techniques is to evaluate the parts in the assembly so that the labour cost can be reduced. In this paper, the mechanical parts within the design and assembly are examined, and an integrated architecture of an assembly model is proposed which includes a proper assembly environment, the interface between the assembly model and feature-based design, and a knowledge-based expert system for assembly analysis. In order to determine satisfactory plans for assembly and to achieve the required functions in the product model, explicit relational information between the major components is implemented. The evaluation of interference checking of the parts and the geometric tolerances (such as perpendicularity, parallelism, and angularity) of the parts in the assembly model are also studied.