Three-Dimensional Synthesis of Manufacturing Tolerances Based on Analysis Using the Ascending Approach

Abstract

The present paper develops a new approach for manufacturing tolerances synthesis to allow the distribution of these tolerances over the different phases concerned in machining processes using relationships written in the tolerance analysis phase that have been well developed in our previous works. The novelty of the proposed approach is that the treatment of non-conventional surfaces does not pose a particular problem, since the toleranced surface is discretized. Thus, it is possible to study the feasibility of a single critical requirement as an example. During the present approach, we only look for variables that influence the requirements and the others are noted F (Free). These variables can be perfectly identified on the machine, which can be applied for known and unknown machining fixtures; this can be the base for proposing a normalized ISO specification used in the different machining phases of a mechanical part. The synthesis of machining tolerances takes place in three steps: (1) Analysis of the relationship’s terms, which include the influence of three main defects; the deviation on the machined surface, defects in the machining set-up, and the influence of positioning dispersions; then (2) optimization of machining tolerance through a precise evaluation of these effects; and finally (3) the optimization of the precision of the workpiece fixture, which will give the dimensioning of the machining assembly for the tooling and will allow the machining assembly to be qualified. The approach used proved its efficiency in the end by presenting the optimal machining process drawing that explains the ordered phases needed to process the workpiece object of the case study.

Modification and Optimization of Cycloidal Gear Tooth Profile Based on Machining Error Compensation

“…Although machining error is a critical factor affecting the actual cycloidal gear profile and theoretical profile, few related studies considered the machining error compensation. Ayadi et al [23] divided the synthesis of machining tolerances into three steps, finally obtaining the best machining process diagram. Guo Jingbin et al [24] measured the full tooth profile error of the cycloidal gear and converted it into the change in the modification amount through Fourier transformation, while not analyzing it from the perspective of the machining error principle.…”