Locating Correctness Analysis and Modification for Fixture Design

In machining processes, geometric accuracy of a manufacturing workpiece mainly relies on the relative position of workpiece to the machining tool. Fixtures are needed to locate the workpiece relative to the machining tool in order to guarantee the manufacturing quality. Therefore, correct locating is the basic condition for designing a fixture. In addition, computer aided fixture design (CAFD) facilitates more cost effective and efficient fixture design. However, heuristic and case-based methods are still common. This paper firstly presents a general framework to verify the locating correctness so as to soundly determine locator number and positions. Secondly, within the scope of CAFD, a computing tool is developed within the Unigraph system for the correctness analysis of fixture locating schemes. Finally, a detailed discussion is made about the modeling process and its verification by means of practical examples. Analyzing results are consistent with practical ones.