To distribute the stiffness on a machine tool reasonably or find out the

optimization target of component stiffness,a way was proposed to identify the distortion sensitivity of the machine component during design.The first work was to build an error model of target machine tool by combining the multi-body system theory and homogeneous coordinate transform.Then,it was supposed that each component produced respectively the unit distortion of six freedoms,and their action value and direction on final execution component were calculated with aforesaid error model.To compare these results, the

influence degree of each component stiffness on the final export precision will be realized. 