Tolerance analysis in machining using the model of manufactured part (MMP) – comparison and evaluation of three different approaches

Abstract

This article aims to compare three different approaches already proposed by the authors regarding the three-dimensional error stack-up analysis in machining. Although the developed error stack-up analysis method comprises of different manufacturing processes, this article is limited to machining operations. This article is built on the previous research of the authors namely the model of manufactured part (MMP) which models the different geometrical deviation 3D impacts on the geometrical and dimensional quality of part produced (error stack-up) in a multi-stage (MS) machining process. In this study, the MMP will be used for developing numerical solution techniques for the aim of tolerance analysis in a MS machining process. The developed solution techniques are classified in two main categories: worst case analysis (WCA) (worst part produced) and stochastic analysis (STA). This article provides an overview of the MMP model and the different solution techniques. The different strategies to simulate the deviation parameters of the model are then discussed. For each of the three proposed solution techniques, its advantages and disadvantages are explored in detail. The performance of the solution techniques is then compared from different points of view (i.e. rapidity, convergence to the global minimum and analysed case … ) through a 3D example, and finally some perspectives are presented.

Keywords:

• tolerance analysis
• process plan evaluation
• errors stack-up
• model of manufactured part

Notes

1. The LHP _s link values are determined by CHP algorithm (positioning function in line with NPC) thus for each instance of the defects parameters value, a unique set of LHP _s values can be calculated.

2. ltz _3G1 refers to the surface number 3 and gauge number 1.