Formation of an energy-efficient cutting tool path in waterjet and laser cutting CNC machines

Abstract

The paper deals with generation of a cutting tool path taking into account the features of waterjet and laser machines. We present a problem model for the standard cutting technology, i.e., every contour contains only one incised point and the contour can be cut out along a single continuous line. The criterion is the duration of cutting tool idling, which has to be minimized. In this model problem, electric power is conserved due to reduction of idling time. It is pointed out that the problem is considered to be an NP-hard one. We describe both common and specific restrictions. The common restrictions do not depend on machine type. The specific restrictions for the waterjet and for the laser machines are different. Three primary stages of cutting tool path generation are distinguished. At the first stage, the sets of possible incised points for every contour are generated taking into account the features of the selected machine type. At the second stage, the initial permutation of contours and the only incised point for every contour are selected by a greedy algorithm. The third stage is optimization of the initial solution by two metaheuristics at the same time—Great Deluge Algorithm (GD) and Threshold Accepting (TA). The best solution of the two obtained is selected. The experiment is performed in the ITAS NESTING nesting system to show the efficiency of method. The obtained solution for both waterjet and laser machine satisfies all restrictions and features. The proposed method shows high performance. It takes the algorithm 3 s on average to find a solution for the waterjet machine and 2 s to find solution for the laser machine based on data on 152 contours.