기하공차에서 공차적층분석을 통한 공차의 조정

Abstract

One of the challenges facing precision manufacturers is the increasing feature complexity of tight tolerance parts. Tolerance is an essential part of design and manufacturing. For tolerance analysis, most common methods are worst case method, statistical method and Monte Carlo Simulation method. These methods do a good job for dimensioning and tolerancing of size and are still used in good capacity. But these methods do not cater precisely for geometrical tolerances. The main limitations of these methods are the following: they do not properly support the application of the envelope rule and of the independence rule to different dimensional tolerances on the same part as prescribed by the standards. A stack is a calculation which determines the maximum or minimum distance (clearance or interference) between two features on a part or in an assembly. Therefore we tried to propose for the development of a new method aimed at addressing such limitations. Tolerance stack of individual components and their assembly have been carried out using graphical approach. Based on the stack tolerance, it can be verified with the design tolerance of the assembly. Based on the comparison, designer has to reassign the appropriate tolerances to fulfil the functionality if required.