Research And Development Of Non-contact Non-ferrous Metal Casting Ingot Laser Marking Equipment

According to the national label standard for non-ferrous metal products,the relevant production information must be carried on the non-ferrous metal casting ingots.The current practice is hand-bonded copper paper,manual lift coding and pneumatic marking,which have the disadvantages of low automation and high waste.Laser marking technology for non-ferrous metal ingots is a new type of marking technology developed in recent years.In the practical non-ferrous metal automatic production line,the application of laser marking is facing the problem of vertical focusing.In view of this problem,a non-contact laser marking equipment for non-ferrous metal ingots has been developed in this thesis.The main research contents are as follows:(1)In non-ferrous metal production enterprises,the position and posture errors of non-ferrous metal stacking in different directions on the actual production line are studied,and the specific error range is given.(2)Aiming at the problem that laser marking is difficult to focus vertically due to the position and attitude errors and errors of non-ferrous metal stacking,a five-axis linkage mechanical structure is designed,and a complete three-dimensional model of the overall mechanical structure and equipment is built.The key feeding system is calculated and analyzed in detail,and the finite element analysis is carried out on the ball screw,the oscillating table system and the upper and lower linear actuators,which have a great influence on the laser marking focal length.(3)According to the actual control function and accuracy requirements,the motion control card type control system is selected.The calculation and selection of servo motor system are carried out,and the specific model is given.According to the actual wiring,the electrical schematic diagram is drawn.According to the layout principle of the electrical cabinet,the electrical components of the control cabinet are arranged and the layout diagram of the components is drawn.(4)In plane fitting,an improved Random Sample Consensus algorithm(RANSAC)is proposed to solve the problem of noise on the marked surface of non-ferrous metal ingots.This algorithm is based on the RANSAC algorithm and uses the disc selection principle of genetic algorithm to overcome the shortcomings of random sampling in the Random Sample Consensus algorithm,which leads to greatly increased iteration times and calculation time.The experimental results show that the proposed algorithm not only retains the advantages of simplicity and noise elimination,but also overcomes the shortcomings of random sampling of RANSAC algorithm,reduces the plane fitting time and obtains reliable plane equation parameters.Finally,the normal vectors are calculated according to the plane equation,and the rotation angles or moving distances of each axis in the five-axis linkage mechanical structure are calculated by the normal vectors and coordinate transformation to achieve automatic vertical focusing calibration.At the end of this paper,five-axis mechanical mechanism,control system and alignment algorithm are tested on the surface of aluminium ingot.The results show that the content of laser marking has high clarity,and two-dimensional code can be effectively scanned.The validity of this method is proved and the design goal is achieved.