Study on Testing and Evaluation of Comprehensive Accuracy of GMC2550u Prototype Bridge-type Machining Centre

Abstract

The performances on accuracy, cutting ability and machining stability of NC machine tools are the three main indicators which user concerned. It is of great importance research on the integrated accuracy for the existing performance of machine tool, improving the prototype machine's performance. According to domestic and foreign standard, an evaluation system of testing item and evaluation indexes for bridge-type CNC machine tool is established. An accuracy testing for prototype of machining centre is carried on by experimental testing method, especially for static accuracy, dynamic accuracy and working accuracy. A series testing such as positional accuracy of machining centre, minimum setting unit error, circular error, dynamic spindle rotation accuracy, dynamic response performance of feed axis, as well as machining accuracy of three types typical acceptance test parts are promoted. Meanwhile, it is focus on the dynamic performance of machining centre such as spindle radial vibration, static stiffness and thermal performance. It is found that the static accuracy meet the requirements while the disparities on machine's acceleration and thermal accuracy somehow exist which have effect on machining accuracy. Synthesizes the testing result of each accuracy target, the machine tool performance and actual accuracy distribution are found. And it can evaluate accuracy problems of prototype machining centre in view of various accuracy items, which gives a direction for machine tool optimization and improvements later.