Tool Thermal Deformation Measurement Research Based On Image Processing Technology

With the continuous popularization of informatization and intelligence of machining,and the continuous improvement of functions,in the manufacturing process of different industries,CNC machine tool processing technology is moving rapidly in the direction of high efficiency,high quality,high precision,high integration and high intelligence.development of.In my country's machinery manufacturing industry,CNC machine tools have become an important core equipment for precision and ultra-precision machining technology.The industry has also put forward higher requirements for its machining accuracy,and CNC machine tool errors are the primary obstacle that restricts machining accuracy.Therefore,reducing the error of CNC machine tools and improving the machining accuracy are not only topics that have been studied by the academic community,but also the problems that the industry needs to solve urgently.The high-speed,high-precision machining center has a high feed rate and spindle speed.During the working process of the machining center,a large amount of frictional heat will be generated at the main components such as the spindle,screw pair,bearing,guide pair,etc.,which will cause more Obvious temperature rise,temperature rise and uneven distribution of temperature field will cause uneven thermal deformation of the machine tool,resulting in changes in the relative position of the workpiece and the tool,and machining errors,which will lead to a decrease in the machining accuracy of the machine tool and the deformation of the tool system Accounted for a higher proportion of thermal error,Therefore,measuring the thermal deformation of the tool during processing and preheating,and adopting appropriate methods to predict the thermal deformation of the tool and thermal error compensation,is of great significance to improving the processing accuracy.The traditional tool thermal deformation measurement method is usually to estimate the amount of deformation through experience after the preheating is completed,and then use theoretical analysis to calculate a certain deformation value,to help the craftsman to accurately understand the deformation,and through a certain method Control and solve the problem of thermal deformation.This traditional measurement method seriously affects the processing efficiency.In order to quickly and easily measure the deformation of the tool during preheating,non-contact image processing technology is now used to measure the thermal deformation of the tool.The purpose of early digital image processing is to improve the quality of the image.It takes people as objects and improves people's visual effects.With the continuous expansion of the application scope of image processing technology,today with the rapid development of computer technology,a large number of complex and sophisticated image processing algorithms follow.At the same time,more and more attention is paid to the selection and improvement of image processing algorithm applications,therefore,this subject uses the camera to simulate the human eye to collect images,and the computer simulates the brain to perform mathematical calculations on the images to realize the machine's cognition of the three-dimensional world.Its practical significance lies in: on the one hand,the measurement of tool thermal deformation can shorten the warm-up time On the other hand,the measurement of tool thermal deformation will also be a key technology to improve the accuracy of precision high-speed CNC machine tools.Aiming at the problems of too long tool preheating time,which affects the processing efficiency and the reduction of processing accuracy caused by thermal errors,this paper takes the ball-end milling cutter as the research object,and proposes a scheme for calculating the thermal deformation of the tool based on image processing technology.The subject research content is as follows:1.The median filter method is selected to achieve image denoising,the histogram equalization method is used to achieve image enhancement,and the traditional edge detection Canny algorithm and the ant colony algorithm are used to extract the edge contour feature of the preprocessed image.Through the comparison of these two image processing algorithms,it is found that the Canny algorithm is more suitable for the tool edge extraction in this paper,so the Canny algorithm is selected to extract the edge contour of the tool.2.After the Canny algorithm rough positioning,the sub-pixel algorithm is used to accurately locate the edge.In this paper,the contour image of the arc of the tool tip is collected,and the least squares fitting method is used to process and calculate the thermal deformation of the tool during preheating.3.On the basis of the above research,a tool edge contour detection image GUI processing system based on Matlab is designed.The main functions of the system include image reading,preprocessing,edge detection,etc.After verification of examples,the functions of the system can be realized.