Problems of Trajectory Building During Laser CNC Processing

The paper deals with the problems of trajectory building during laser computer numerical control (CNC) processing and presents a new approach to the optimization of the CNC tool trajectory during laser treatment of irregular shapes. The development of the firmware of the CNC machines encounters a number of problems, the most important of which is minimization of the processing time. Two main methods of time reduction are provided—by increasing speed of the treatment using smooth aliasing of acceleration/deceleration curves and reducing the number of auxiliary moves. The processing is represented as nodes, forming a terminating device trajectory. The CNC controller defines trajectory between the nodes, and the terminator is moved from node to node step-by-step. Decreasing the processing time is possible when the CNC tool is scanning paths to be processed and combine acceleration/deceleration curves to reach a maximum speed is considered. A genetic algorithm with crossover similar to the crossover used to solve the travelling salesman problem to reduce the number of auxiliary paths is proposed. The chromosomes formed by building blocks, each of them defining trajectory segments sequence and their orientation are compiling the used algorithm. To change the adjacent segments, heuristics is used so the path between ends of segment, hence the length of the auxiliary part, will be as short as possible.