Industrial robots have been wildly used in machining applications due to its high flexibility

high automationlevel and lowcost. However

the relatively low stiffness of robots seriously influences their machining accuracy and quality. This paper built a singularity measurement model of the robot posture under the constraint of joint-limits. Based on the robotic static stiffness model

a comprehensive robotic stiffness performance evaluation method was proposed. Finally

on the basis of redundant degree of freedom

an off-line machining configuration optimization method of six-revolute serial robots was addressed

which far away from singularity and joint-limits meanwhile achieved the optimum stiffness. Themethod could improve robotic kinematics performance and machining quality effectively through machining experiment.