A study of kinematic performance of the manipulator with six degrees of freedom KUKA KR5 ARC HW, used in welding arc is presented. The performance of this manipulator will be measured in terms of efficiency in the movement of its joints, making movement of the end-effector. The measure used is called manipulability index, which was proposed by Yoshikawa and will be the basis for calculating the manipulator performance. The manipulability index is one of the parameters to optimize of a multiobjective method of trajectory planning in serial manipulators used in welding. The index highlights among other measures because allows to quantify the proximity of the robot to a singularity, which is ideal for identifying paths welding with continuous and soft movements at the robot joints.