基于多重相关特征质量损失函数的并行公差设计

基于多变量质量损失函数,推导了多重相关特征产品的质量损失与有关零件工序公差的函数关系,建立了基于制造成本-质量损失的并行公差设计的优化综合模型,其目的是寻求制造成本和质量损失之间的平衡,以实现相关特征产品的设计公差与工序公差并行优化分配,达到提高产品质量和降低成本的目的。圆锥齿轮装配的并行公差设计实例验证了所提方法的有效性。     

基于制造成本与质量损失的并行公差设计

研究产品质量损失与产品尺寸公差的关系 ,提出具有多个相关装配尺寸产品的质量损失 ,并把它表示成工序公差的函数。利用成本 -公差函数和产品的质量损失函数 ,给出基于产品最低制造成本和多个相关装配尺寸产品质量损失的并行公差设计优化模型 ,实现公差的并行设计 ,最后通过工程实例验证所提出的方法     

基于信噪比多元质量损失和制造成本的并行公差设计

质量损失是由于产品的功能波动所造成的,损失大小可由质量函数确定。在无量纲“标准化”多元质量损失函数的基础上,采用信噪比衡量各质量指标的波动,建立一般情形下的基于信噪比的多元质量损失模型,并把它表示成多个相关装配尺寸产品的工序公差函数。利用成本-公差函数和产品质量损失函数,给出基于产品最低制造成本和多个相关装配尺寸产品质量损失的并行公差设计优化模型,实现公差的并行设计,最后通过工程实例验证所提出的方法。     

多工序尺寸及公差优化

为提高产品制造质量、降低产品制造成本,提出了一种多工序尺寸及公差的优化方法.该方法综合考制造成本、质量损失和加工能力指数,以加工能力指数分别修正制造成本一公差函数和质量损失函数,在工序内建立总成本一公差函数模型.在此基础上,采用目标层解法优化特征内的各个工序基本尺寸和尺寸公差,最终达降低特征总成本的目的.最后以一个仿真实例验证了该方法的可行性.     

基于粒子群算法的公差分配优化方法

基于成本—公差模型和质量损失模型,以加工能力和装配尺寸链的功能约束条件为标准,以制造成本最低、质量损失最小为优化目标,建立兼顾产品成本和质量的公差分配的多目标函数优化模型。基于粒子群优化算法,按照从全局到局部的寻优策略,用线性调节方法来确定其参数的变化规律,进而应用MATLAB软件对建立的函数模型进行优化计算,得到产品的生产成本和质量损失之间的关系曲线,可为公差分配提供更多的解决方案和更可靠的理论依据。     

多工位装配过程夹具系统公差和维护综合优化设计

提出一种面向二维多工位装配过程、综合考虑装配夹具系统全寿命周期成本、产品零件孔制造成本和产品质量损失成本的公差和维护综合优化方法。分析多工位装配尺寸偏差传递关系,建立多工位装配过程产品质量损失模型。然后根据4-2-1夹具定位原则,构建考虑夹具磨损过程损失的夹具定位销副偏差统计数字特征模型。继而发展了以夹具系统全寿命周期成本、零件孔制造成本和和产品质量损失成本为装配总成本最小化的定位销公差、零件孔公差与更换周期优化模型。以汽车侧围装配过程为例,分别研究定位销公差、零件孔公差、定位销更换周期、配合间隙、平均磨损率和磨损率方差对装配总成本的影响,并优化设计定位销公差、零件孔公差和定位销更换周期。所提出的综合优化设计方法比采用定位销等公差设计、零件孔等公差设计、定位销与零件孔等公差设计和定周期更换设计的装配总成本分别减少了16.25%、11.31%、39.93%和13.54%。该方法为产品装配夹具系统高质量低成本设计提供了一种新的途径。     

一种新的公差高度数学模型的研究

本文提出了一种新的公差设计的多目标优化模型。该模型是以各组成零件的中工成本（即成本公差模型）和质量损失成本之和最小作为多目标函数。实验结果表明，这种方法所给出的公差较符合经济加工的要求。     

一种新的公差设计数学模型的研究

本文提出了一种新的公差设计的多目标优化模型。该模型是以各组成零件的加工成本（即成本公差模型）和质量损失成本之和最小作为多目标函数。实验结果表明，这种方法所给出的公差较符合经济加工的要求。     

CAPP中的工序公差设计及技术经济评价

研究CAPP系统的技术经济评价问题,提出将加工成本和质量损失成本总和最小作为CAPP系统的经济性质评价指标;给出一种能对CAPP系统进行定量技术经济评价的工序公差设计数学模型;该模型可用于工序公差优化设计和优选加工方法,给出了一个仿真实例。     

基于资金时间价值的并行公差优化设计

总结了经典的成本公差模型,基于资金的时间价值原理对经典成本公差模型进行优化,提出了多种优化后的成本公差模型计算方法。利用优化后的成本公差模型,将制造成本、质量损失成本同时考虑到并行公差设计的目标函数中,实现了并行公差的优化设计。通过工程实例证明了所提方法的有效性,结果表明,优化后的成本公差模型更贴近实际,计算得到的总成本更为合理,有效地反应了物价上涨、通货膨胀、资金的时间价值等现实因素。     

Optimal tolerance design for products with correlated characteristics by considering the present worth of quality loss

The quality loss function proposed by Taguchi provides a quantitative measurement of product quality when product’s quality characteristic value deviates from the ideal target at an arbitrary time. However, product use causes degradation on its quality characteristic, and since such a deviation can be changing over time, so can its quality loss. The quality loss caused by degradation on quality characteristic has not been considered in most research. In this paper, the time value of money for quality loss and product degradation over time is integrated into the total cost model, and a new optimization model for the tolerance design of products with correlated characteristics is established. The discussions focus on the multivariate quality loss function as an extension of the Taguchi loss function, which is used to model quality loss due to product degradation as a continuous cash flow function under continuous compounding. The optimal tolerance design is achieved by minimizing the total cost, which is the sum of manufacturing cost and the present worth of expected quality loss. An illustrative example is presented to demonstrate the effectiveness of the proposed model.     

公差稳健优化设计的研究

为了解决产品加工成本与质量稳健的协调性问题,提出了一种新的公差稳健优化设计数学模型.依据公差稳健设计的思想,考虑产品质量的模糊性,以封闭环误差分布概率密度函数的方差和优质品概率之比为设计目标,建立了公差优化设计产品质量稳健性损失成本目标函数,并研究了优质品率和封闭环误差分布方差的确定方法.以加工成本和产品质量稳健性损失成本为目标,以模糊装配可靠度、可取公差极限范围为约束条件,建立了公差多目标优化数学模型.举例说明了文中所述的公差稳健优化设计方法的应用,采用遗传算法实现了公差的多目标优化设计.实例表明,该方法能够协调零件的加工成本和产品质量的稳健性损失成本,使优化指标的综合性能最佳.     

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.     

轴一套类零件配合尺寸公差最优设计的研究

公差设计的优劣不仅直接影响产品零件装配精度的实现,而且对产品制造成本亦将产生重大影响。文章对轴－套类零件制造（加工与装配） 成本的各因素进行了分析,提出了达到装配精度要求的最优装配方法的判定准则,建立了生产成本最低的轴－套类零件最优公差设计的数学模型,并用实例验证了该模型在实际中的正确性与有效性。     

公差设计多目标模型及其粒子群优化算法研究

为解决成本一公差设计模型中忽视产品质量的问题，以新型的田口质量观和Pareto最优解集概念为基础，提出了一种公差设计多目标模型。该模型将加工成本和质量损失分别作为设计目标，并以统计法公差装配成功率为约束条件，获得了比极值公差法更加宽松的公差限。改进了传统的粒子群优化算法，利用Pareto最优性重新定义粒子，然后采用快速非支配排序技术进行粒子的适应度排序，使其能够有效地对多目标模型进行求解。该算法对具体工程实例求解时，一次运行就可求得令人满意的Pareto最优解集，设计者可以根据生产实际和市场需求从中进行选取。通过对求得的Pareto进行最优前沿的分析，可得到该类零件公差设计的特性，其结果验证了公差诒计的一船规徨．     

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。     

The study of cost-tolerance model by incorporating process capability index into product lifecycle cost

To reduce the cost of manufacturing systems, many studies of cost minimization have been performed. Since tolerance design significantly affects the manufacturers’ cost, the optimization of cost-tolerance allocation will be an important issue for reducing these costs. Costs incurred in a product life-cycle include manufacturing cost and quality loss. However, most cost-tolerance optimization models frequently ignore the concept of quality loss and may not lead to an accurate analysis of the tolerance. Until now, process capability analysis has been the tool used to evaluate the adequacy of a production tool in meeting a quality target. Hence, the concept of process capability analysis should be included into the cost-tolerance optimization model. In this study, a flexible cost-tolerance optimization model will be constructed by integrating the process capability index into the product life-cycle cost function. The constructed cost-tolerance optimization model simultaneously considers the manufacturing cost of the components, the process capability of the manufacturing operations, and the quality loss of products. The decision-maker can apply the proposed cost-tolerance optimization model to determine a reasonable tolerance with minimum total cost including consideration of the process capability .     

Process mean, process tolerance, and use time determination for product life application under deteriorating process

Robust design can significantly improve a producer’s competitive ability to deliver high-quality products with low development cycle time, quality loss, failure cost, and tolerance cost. However, during usage by a consumer, the functional performance of a product or some of its components may change as use time passes, leading to unexpected product failure that is usually costly in both time and money. The cost of these failures may influence the determination of optimal use time and optimal initial settings as compensation for the possible process mean changes during consumer usage. In addition to finding use time and initial settings for proper quality performance, the determination of process mean and tolerance also needs to be considered. As is known, changes in process means acquired quality loss and variability, while process tolerance has an effect on tolerance-related costs and quality loss. Because there exists a dependency among use time, initial setting of process mean, process mean, and process tolerance, these values must be determined simultaneously. Thus, in this paper, an optimization model with an acceptable reliability value is developed to minimize total cost, including quality loss, failure cost, and tolerance cost, by determining optimal use time, initial settings, process mean, and process tolerance, simultaneously. Applications of single and multiple components are presented to explain the proposed models. Finally, sensitivity analysis and model discussions on some decision variables are performed.     

基于广义装配原理的产品生长型设计

通过研究生物生长与产品设计之间的相似性,提出了基于广义装配原理的生长型设计过程,研究了广义装配原理的三个理论构成。首先,在产品生长阶段,为实现生长过程中的自然选择,提出了以复杂度理论为控制因素的设计推理策略;其次,提出了功能公差设计理论,通过加工成本以及基于多因素的模糊质量损失成本体现广义装配成本,在确保产品功能的同时,以较低的装配与制造成本为公差的分配策略;在产品进化阶段,为保证产品良好的装配性能,采用了虚实结合设计技术。将以装配质量因素为核心的产品复杂度、精度以及制造、装配成本等众多设计因素并行集成于生长型设计过程中,实现了以全生命周期装配质量保障为核心的产品生长型设计。