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公差分析和公差分配是公差设计的两个重要方面。本文介绍了绿色制造的概念和关键技术,研究了绿色制造在公差设计中的应用,提出了在绿色制造技术下的公差分配优化的目标函数,并且论述了基于绿色制造的公差优化的方法。 相似文献
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公差稳健优化设计的研究 总被引:2,自引:0,他引:2
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. 相似文献
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基于价值分析的装配尺寸链公差可靠性优化分配 总被引:1,自引:0,他引:1
讨论了公差与制造成本之间的关系,同时从概率设计的角度提出了装配尺寸链可靠度的概念及设计方法。建立了以总制造成本为目标函数,装配尺寸可靠度为约束条件的装配尺寸链优化 设计数学模型,实例设计结果表明这里提出的公差分配方法较传统方法更科学,准确。 相似文献
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尺寸公差与形位公差混合优化分配 总被引:1,自引:1,他引:0
为解决尺寸公差与形位公差混合优化分配问题,提出了一种公差优化分配方法.根据成本-公差函数和尺寸公差与形位公差的关系,建立了以最小制造总成本为目标的非线性公差混合优化分配模型.该模型的约束包括装配尺寸链的功能要求和加工能力.求解该模型能同时得到优化的尺寸公差和形位公差.最后,分别用公差混合优化分配法和传统方法对一个实例进行公差分配,结果表明所提方法比传统方法更优越. 相似文献
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Solid Edge的2D制图提供了全面的尺寸和标注工具,它能在数秒内快速创建完整详细的工程图,是易学、高效、易用的机械CAD系统。但在产品的设计中,零件和装配件的尺寸链计算与分配工作量仍然较大,而Solid EdgeV16以上版本提供了快速计算标注尺寸链公差的工具,实现了计算机完成尺寸链的计算与分配,增强了Solid Edge对机械产品的设计能力。 相似文献
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Dr B. K. A. Ngoi M. S. Seow 《The International Journal of Advanced Manufacturing Technology》1996,11(1):34-42
The development of tolerance charts has come a long way from the past manual methods to the current computer-aided models. As a result, many techniques have emerged over the years. However, the area of geometrical tolerance charting has not been given much attention. In view of this, this paper addresses both linear and geometrical tolerance control.The method proposed in this paper allows the user to construct a model directly from the process plan. The relevant process links between any two planes which are required to satisfy both the linear and geometrical requirements are easily obtained from the model. Having established all the appropriate constraints, the linear programming optimisation software is used for the determination of the unknown working dimensions and tolerances.In essence, this paper presents a new methodology for deriving the process links from the process plan and also highlights the significance of the use of linear programming in achieving the optimal tolerance mix or combination. 相似文献
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为解决复杂系统多学科可靠性设计优化过程中由于存在多源不确定性和多层嵌套而导致的计算效率低的问题,将近似灵敏度技术与两级集成系统综合策略(Bi-level integrated system synthesis,BLISS)和功能测度法集成,提出一种能同时处理随机和区间不确定性的序列化多学科可靠性设计优化方法。基于概率论和凸模型对混合不确定性进行量化,提出一种随机和区间不确定性下的混合可靠性评价指标,并基于功能测度法建立多学科可靠性设计优化模型。采用近似灵敏度信息替代实际灵敏度值,将近似灵敏度技术同时嵌入多级多学科设计优化策略和多学科可靠性分析方法中,避免每轮循环都进行全局灵敏度信息的分析与迭代,提高了计算效率。基于序列化思想同时将四层嵌套的多学科可靠性设计优化循环和三层嵌套的多学科可靠性分析过程进行解耦,形成一个单循环顺序执行的多学科可靠性设计优化过程,避免了每轮循环对整个可靠性分析模型进行迭代分析的过程,减少灵敏度分析和多学科分析次数。以汽车侧撞工程设计为例,验证了该法具有同时处理随机和区间不确定性的能力,并且计算效率较传统方法分别提高了10.98%和23.63%,表明该法具有一定工程实用价值。 相似文献
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Dr B. K. A. Ngoi O. J. Min 《The International Journal of Advanced Manufacturing Technology》1997,13(10):729-737
The interaction between components in an assembly plays a major role in the performance and reliability of the assembly. However, in conventional design, the dimensions and tolerances of components are usually assigned intuitively to satisfy design constraints. Tolerance analysis is then performed to determine the critical tolerance accumulation that results from the assembly. The tolerances are then modified so that the interaction requirements are satisfied. This approach relies on the experience of the designers and the results may not be an optimum.This paper presents a direct method to determine the working dimensions and tolerances of components that allows control of the assembly interaction. The model is easy to construct and it provides a clear picture of the entire process and assembly links. Using the model, a set of linear equations is formulated directly based on the design constraints and interaction requirements. With appropriate constraints derived in terms of the process capabilities, the desired working dimensions and tolerances can be determined using LINDO, software for solving the linear programming problem. This approach allows the working dimensions and tolerances of all components in an assembly to be determined concurrently. 相似文献
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Optimal Tolerance Allocation Based on Fuzzy Comprehensive Evaluation and Genetic Algorithm 总被引:11,自引:6,他引:5
S. Ji X. Li Y. Ma H. Cai 《The International Journal of Advanced Manufacturing Technology》2000,16(7):461-468
It is very important to know how to allocate tolerances economically for parts in a CAD/CAM system because this directly affects
the machining costs of the parts. A new approach based on fuzzy comprehensive evaluation (FCE) and a genetic algorithm (GA)
is presented to obtain a rational tolerance allocation for the parts. First, the current methods for tolerance allocation
are reviewed in detail. Then, FCE is used to evaluate the machinability of a part; a new optimal model, which can fully exploit
DFA (design for assembly) and DFM (design for manufacturing), is established by combining the functional sensitivity factors
and machinability factors of parts. A genetic algorithm (GA) is developed and used to verify the feasibility of the above
method; the computed result shows that the method can produce tolerance allocations economically and accurately. 相似文献
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An optimal approach for process tolerance balancing is presented. The new approach is based on process capabilities and is
to be used in the stage of process planning. A nonlinear programming model is used to simultaneously optimise process tolerances
of required operations. In the optimisation model, the objective function is to minimise the total manufacturing cost with
different weighting factors. Using the estimated standard deviations of the dimensions and the manufacturing cost-tolerance
functions, the constraint equations for the process tolerance chains and the manufacturing capability indices are established,
together with a model for the economical tolerance bounds of machine tools. A practical example was used to verify the usefulness
of the proposed approach. The results of the comparative study show that the proposed approach is more advantageous in relaxing
tolerance requirements and in reducing scrap rates generally, compared with the existing methods.
ID="A1"Correspondance and offprint requests to: Dr Y. Gao, Department of Mechanical Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon,
Hong Kong. E-mail: meygao@ust.hk 相似文献