A proposition of 3D inertial tolerancing to consider the statistical combination of the location and orientation deviations

TL;DR

This paper introduces a 3D statistical tolerancing method for assembly mechanisms, extending the 1D inertial criterion to include location, orientation, and form deviations, and compares it to traditional worst-case tolerancing.

Contribution

It proposes a novel 3D statistical tolerancing approach using modal characterization and an extended inertial acceptance criterion, enhancing accuracy over traditional methods.

Findings

The 3D statistical tolerancing method is effective for complex assemblies.

Comparison shows advantages over worst-case tolerancing in certain scenarios.

Application to a lever mechanism demonstrates practical utility.

Abstract

Tolerancing of assembly mechanisms is a major interest in the product life cycle. One can distinguish several models with growing complexity, from 1-dimensional (1D) to 3-dimensional (3D) (including form deviations), and two main tolerancing assumptions, the worst case and the statistical hypothesis. This paper presents an approach to 3D statistical tolerancing using a new acceptance criterion. Our approach is based on the 1D inertial acceptance criterion that is extended to 3D and form acceptance. The modal characterisation is used to describe the form deviation of a geometry as the combination of elementary deviations (location, orientation and form). The proposed 3D statistical tolerancing is applied on a simple mechanism with lever arm. It is also compared to the traditional worst-case tolerancing using a tolerance zone.