Abstract: The development of high precision molding equipment is the key for near-net shape technology in our country. Research and development of parallel driven mechanical press with multi-link becomes important trends. How to determine the key error sources which influence the precision of servo press, thus to distribute the accuracy of the main parts economically and reasonably, is important for the design of high precision servo press. Based on the available research results, the definition, index and affecting factors of servo press’s precision are discussed. Then the structural characteristics of symmetry multi-linkage mechanism are analyzed, and precision analysis models of kinematics output are developed based on loop incremental theory; through sensitivity analysis, the key error sources are identified; considering the manufacturing cost and the constraints of mechanism reliability, the accuracy of the main parts is distributed. A case study of 4-RRPaR&PRPa R servo press is presented by using Monte Carlo method for demonstration of the proposed approaches. The result shows that the error factors which have relatively important influence on the servo press’s precision can be identified effectively, and the requirement of mechanism reliability can be satisfied by adjusting these factors’ tolerance.

Key words: parallel driven multi-linkage press, precision modeling, sensitivity analysis, accuracy synthesis