The Prediction of Fixture Comprehensive Influence on the Machining Error of Features Pattern

Abstract

The position and orientation deviation of workpiece caused by the fixing errors of the fixture influences the machining accuracy of workpiece. This paper presents a method of predicting the fixture induced error and its influence on the machining accuracy of features pattern. Firstly, the mathematical model for predicting fixing error caused by locators and locating surface geometrical errors and caused by clamping force and machining force is formulated. Then, based on the 3-2-1 positioning fixture, the influence of fixing errors on the machining accuracy of features pattern is analyzed after introducing the definition, inspection and evaluation method for the composite position error of features pattern. Finally, taking 4-holes pattern in rectangular distribution as an example, the process of predicting the composite positional error of features pattern is detailed and a simulation experiment is conducted. The results show the rightness and validity of this method.