Development Of CNC Cutting Machine Height Adjustment System

With the development of laser technology and automation technology,the application of laser cutting technology is more and more extensive.In the process of laser cutting,the surface of the object being cut is likely to have irregular fluctuation,which leads to the deviation of the laser focal point.This will cause significant influence on the cutting quality.Therefore,it is needed to adjust the height of cutting head in real time so as to keep the distance between the cutting head and the object being cut.At present,there are still some manufacturers in the domestic market who can only adjust the height of the cutting head manually.The others use automatic height adjustment systems which mostly have some defects in accuracy and speed.In this paper,a numerical control cutting machine height adjustment system is introduced,which realizes automatic height adjustment in high precision and high speed during the laser cutting process.The height adjustment system measures the distance between the cutting head and the object being cut by the non-contact capacitive displacement sensor on the cutting head,which convert the change of distance into the change of the capacitance.Micro capacitance measurement circuit measures the capacitance and converts it into the differential frequency signal which is convenient for the motion controller to read.The motion controller reads the frequency signal as the position feedback signal of the position loop,and outputs the analog voltage signal according to the calibration data and the setting of the following height.Servo driver drives the servo motor according to the analog voltage of the motion controller.The servo motor then drives the lifting body which moves the cutting head in the vertical direction,so as to achieve the purpose of height adjustment.In this paper,the overall structure of the system and the selection of each section are firstly introduced.Then the design of the two sets of micro capacitance measurement circuit,multi vibrator and LC oscillation are proposed.The following section focuses on the design and programming of calibration program and following program on the motion controller.The design of the linearization algorithm and PID algorithm are also discussed.The next part introduces the construction and connection of motion control system.Finally,the design and construction of the test platform are introduced,and the test data and results are analyzed.The numerical control cutting machine height adjustment system introduced in this paper has been tested on the test platform.The test results show that the system design is feasible and stable.It can achieve automatic height adjustment with high precision and speed.This system improves the quality of cutting products and the efficiency of cutting machine,meeting the requirements of the market.