CO₂ Laser Power Feedback System For Precision Die-board Cutting

With the continuous development of social productivity,people pay more and more attention to the quality of finished products after the printing of commodity package,therefore,the demand for die-cutting boards used for preparing package is steadily on the increase.For non-metal processing industries such as die-board cutting,the production efficiency and processing accuracy of traditional sawing machine cutting technologies are gradually unable to meet the needs of modern industrial production;the efficient,high-precision and low-cost laser die cutting machines have become a new development direction.The fast axial flow CO2 laser is the preferred laser for precision die cutting due to its advantages of high electro-optic conversion efficiency,wide output power range,good power stability and high absorption rate of non-metallic materials.However,the die-cutting board processed by laser has the problems of "match end",non-uniform cutting seam width and insufficient power follow-up control.Therefore,this paper proposes a set of fast axial flow CO2 laser power feedback system based on STM32F103ZET6,and the main research work include:(1)A new type of high-speed laser power meter is designed.The response speed of the power meter is in the order of milliseconds.The real-time monitoring of kilowatt-level CO2 laser power can be achieved through tail mirror sampling,which is capable of solving the difficulty of high-speed detection of CO2 laser power.(2)Through the real-time detection of laser power by the high-speed CO2 laser power meter designed in the paper,the current power cascade PID control program is designed,and a method for real-time adjustment of laser power according to the detected cutting speed is proposed to avoid the cutting seam width changes caused by the acceleration and deceleration of machine tool.(3)A digital power feedback control system is designed with STM32F103ZET6 as the platform.The hardware design of the laser power feedback system is completed,including the chip minimum system,digital/analog sampling,detection,output circuit,PCB board layout and wiring as well as the overall anti-interference design,etc.of the hardware.The software design of the laser power feedback system is completed,including the main program design of mode control and the subprogram design of the function modules.The speed and power matching program is designed to meet the requirements of power follow-up control.(4)Through simulation analysis,the designed current power cascade PID control program can perfectly compensate for the power interference factors and improve the power stability.The experimental results show that the response speed of the high-speed CO2 laser power meter is less than 100 ms,which is lower than the second-level response speed of the current power meter,and the laser power stability of the feedback control system is better than ±0.5%.