Practical application of the classical methods of in-terpolation, such as Lagrange’s, Bessel’s, Stirling’s, Newton’s and others, cannot always provide sufficient accuracy in the restoration of lines according to the requirements of modern technologies. In this paper, recommendations for the improve-ment of interpolation accuracy are given, including the transition to the method of cubic splines. The results of research are used to create a route for arc welding in order to increase the perfor-mance of industrial robot.