A numerical study on effect of temperature and inertia on tolerance design of mechanical assembly

Abstract

Purpose -Due to technological and financial limitations, nominal dimension may not be able achievable during manufacturing process. Therefore, tolerance allocation is of significant importance for assembly. Conventional tolerance analysis methods are limited by the assumption of the part rigidity. Every mechanical assembly consists of at least one or more flexible parts which undergo significant deformation due to gravity, temperature change, etc. The deformation has to be considered during tolerance design of the mechanical assembly, in order to ensure that the product can function as intended under a wide range of operating conditions for the duration of its life. The purpose of this paper is to determine the deformation of components under inertia effect and temperature effect. Design/methodology/approach -In this paper, finite element analysis of the assembly is carried out to determine the deformation of the components under inertia effect and temperature effect. Then the deformations are suitably incorporated in the assembly functions generated from vector loop models. Finally, the tolerance design problem is optimized with an evolutionary technique. Findings -With the presented approach, the component tolerance values found are the most robust to with stand temperature variation during the product's application. Due to this, the tolerance requirements of the given assembly are relaxed to certain extent for critical components, resulting in reduced manufacturing cost and high product reliability. These benefits make it possible to create a high-quality and cost-effective tolerance design, commencing at the earliest stages of product development. Originality/value -With the approach presented in the paper, the component tolerance values found were the most robust to withstand temperature variation during the product's application. Due to this, the tolerance requirements of the given assembly are relaxed to a certain extent for critical components, resulting in reduced manufacturing cost and high product reliability. These benefits make it possible to create a high-quality and cost-effective tolerance design, commencing at the earliest stages of product development. IntroductionIn the fiercely competitive global economy of today, product success is awarded to the company that can guarantee quality at a low cost. With such demands, the use of tolerance allocation has become a vital link between the product design and manufacture. Tool wear, fixture imperfections, chatter and countless other causes produce deviations from a part's ideal design. The designer must make an allowance for variations in the actual parts made. Such deviations are permitted, within limits, through the use of tolerances. However, the challenge is to permit as much as variation as possible, to minimize production costs, while still meeting critical functionality when components are assembled. Tolerance design takes the guesswork out of tolerance assignment by determining how sensitive the critical assembly dimensions are to part variatio...

3D tolerance modeling and geometric precision analysis of plane features for flexible parts

“…At present, tolerance analysis mainly includes the vector loop method (Gao et al , 1995), matrix method (Whitney et al , 1994), Jacobian-torsor method (Desrochers et al , 2003) and T-map method (Jian et al , 2007), all of which are based on rigid body assumption without considering the influence of parts deformation on tolerance analysis (Corrado and Polini, 2017; Jayaprakash et al , 2012; Polini and Corrado, 2016). With the further research, it is necessary to study the theory and geometric precision coupling mechanism for flexible parts based on the N-GPS.…”

A new method of rigid assemblies stochastic 3D tolerance analysis including thermal performance.

“…The paper considers only a 2D WC condition and does not make statistical considerations. Jayaprakash et al [2012] use the Bjorke [1989] classic gearbox example to consider thermal and inertia effects on functional tolerances using FEA. The vector loop method is used to represent the Björke tolerance chain.…”

“…A meshed model was calculated using FEM for thermal design. Jayaprakash et al [2012] used also Bjorke's gearbox example for tolerance and thermal design. A FEM simulation was used to calculate both the thermal dilatation and inertia loads of parts.…”