Purpose

This paper aims to illustrate the tolerance optimization method based on the assembly accuracy constrain, precession constrain and the cost of production of the assembly product.

Design/methodology/approach

A tolerance optimization method is an excellent way to perform product assembly performance. The tolerance optimization method is adapted to the process analysis of the hatch and skin of an aircraft. In this paper, the tolerance optimization techniques are applied to the tolerance allocation for step difference analysis (example: step difference between aircraft cabin door and fuselage outer skin). First, a mathematical model is described to understand the relationship between manufacturing cost and tolerance cost. Second, the penalty function method is applied to form a new equation for tolerance optimization. Finally, MATLAB software is used to calculate 170 loops iteration to understand the efficiency of the new equation for tolerance optimization.

Findings

The tolerance optimization method is based on the assembly accuracy constrain, machinery constrain and the cost of production of the assembly product. The main finding of this paper is the lowest assembly and lowest production costs that met the product tolerance specification.

Research limitations/implications

This paper illustrated an efficient method of tolerance allocation for products assembly. After 170 loops iterations, it founds that the results very close to the original required tolerance. But it can easily say that the different number of loops iterations may have a different result. But optimization result must be approximate to the original tolerance requirements.

Practical implications

It is evident from Table 4 that the tolerance of the closed loop is 1.3999 after the tolerance distribution is completed, which is less than and very close to the original tolerance of 1.40; the machining precision constraint of the outer skin of the cabin door and the fuselage is satisfied, and the assembly precision constraint of the closed loop is satisfied.

Originality/value

The research may support further research studies to minimize cost tolerance allocation using tolerance cost optimization techniques, which must meet the given constrain accuracy for assembly products.

中文翻译：

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飞机产品装配最优公差分布方法的知识创建与应用

目的

本文旨在说明基于装配精度约束、进动约束和装配产品生产成本的公差优化方法。

设计/方法/方法

公差优化方法是执行产品装配性能的极好方法。公差优化方法适用于飞机舱口和蒙皮的工艺分析。在本文中，公差优化技术被应用到公差分配的阶梯差分析（例如：飞机客舱门和机身外壳之间的阶梯差）。首先，描述了一个数学模型来理解制造成本和公差成本之间的关系。其次，应用惩罚函数法形成公差优化的新方程。最后，利用MATLAB软件计算170次循环迭代，了解新方程对公差优化的效率。

发现

公差优化方法是基于装配精度约束、机械约束和装配产品的生产成本。本文的主要发现是满足产品公差规范的最低组装和最低生产成本。

研究限制/影响

本文阐述了一种有效的产品装配公差分配方法。经过 170 次循环迭代后，发现结果非常接近原始要求的公差。但可以很容易地说，不同的循环迭代次数可能会产生不同的结果。但优化结果必须接近原始公差要求。

实际影响

从表4可以看出，完成公差分布后闭环的公差为1.3999，小于且非常接近于原来的公差1.40；满足舱门外皮与机身的加工精度约束，满足闭环装配精度约束。

原创性/价值

该研究可能支持进一步的研究，以使用公差成本优化技术最小化成本公差分配，该技术必须满足装配产品的给定约束精度。