Automatic Tool-setting Technology Of CNC Machine Tools Based On Machine Vision

Tool setting is an important technique and process during the NC machining. It influences the processing accuracy and efficiency of the CNC machine directly. Traditional tool setting method takes time and effort, and the stability of the accuracy is difficult to maintain. Besides, it has a high production cost and low production efficiency. As the difference of the length and the width of the tool can be calculated automatically by the tool auto-checking instrument and the difference can be stored in the system, so it only need to set the standard knife, thus it saves time greatly and improves the production efficiency. High precision sensor with its control circuit and the mechanical structure are used by the tool auto-checking instrument to operate the tool setting and record data. Then the tool direction recognition, operation, compensation and access will be conducted in the CNC system. As an integrated technology, the machine vision can finish the detection and the location of the target contactlessly, fast and reliably. Then the control operation is realized by utilizing the human-computer interaction interface and thus the tool setting will be completed. Based on this, this paper presents a new method of automatic tool adjustment based on machine vision technology and CNC control system.An automatic tool adjustment system of the CNC micro milling machine based on machine vision is primarily researched and developed in this paper. The rectangle and rounded parts detection methods is proposed and the high precision calibration of the industrial Camera is realized. In addition, a visual detection system is designed and the automatic tool adjustment experiment of the CNC micro milling machine is finished. This paper is organized as follows.(1) The selection, installation and debugging of the industrial cameras, industrial lens, image capture card and light is finished, an image acquisition system is designed and developed based on VS2010and FlyCapture2SDK.(2) The three-dimensional model of the machine vision experimental system is designed and the installation method of different angles and positions aimed at different camera usage are designed, also the processing and assembling of the3D model is finished. (3) The calibration of the industrial camera is finished and the camera model and calibration process are introduced. Furthermore, the parameter calibration of the industrial camera is finished according to ZHANG’S calibration method.(4) The parts inspection system based on machine vision technology is developed and the dimension measurement and orientation of the parts are realized. The rectangular detection method based on Harris corner is proposed and the performance comparison with the rectangular detection method based on Hough corner is conducted.(5) The automatic tool-setting system of the CNC Machine Tools based on machine vision is developed, the plane calibration method based on CNC system is proposed and the tool parts location arithmetic is designed. In addition, the range measurement in Z-axis direction between the tool nose and the machining part is realized, the automatic tool-setting experiment is finished and the result is analyzed.