Design Of Optical Precision Tool Setting For Ultra-precision Lathe And Analysis Of The Effect Of Tool Setting Error

Precision optical components such as optical lenses have excellent performance and are widely used in various industries.The processing of precision optical parts and their molds requires sub-micron shape and dimensional accuracy,which belongs to the category of ultra-precision processing.In ultra-precision turning,tool wear,tool nose radius measurement error,and tool setting error will seriously affect the machining quality of the workpiece.The on-machine measurement optical tool setting device uses machine vision technology to accurately measure the tool tip radius,reduce tool setting errors,and observe tool wear from the tool image.In order to ensure the machining accuracy,after the tool setting device is used to perform tool setting in actual processing,a trial cutting method is also required to accurately center the tip of the tool,but the trial cutting method is complicated in operation and is not conducive to improving the efficiency of ultraprecision machining.In this paper,an optical tool setting device applied to ultra-precision lathes is designed,which can accurately detect the wear of the tool and the value of the arc radius of the tool tip to reduce the tool setting error.Then,simulation is used to predict the shape of the workpiece when there is a tool setting error,so as to use the optical tool setting device to reasonably control the tool setting error and improve the tool setting efficiency according to the surface accuracy requirements.The main research work is as follows:First of all,considering the requirements of detection accuracy and the size of the tool tip,a suitable industrial camera and monocular microscope were selected,and then different illumination methods were designed for image acquisition for wear detection and tool tip arc detection.experiment platform.In order to achieve precise focusing of the blade tip,a variety of image sharpness evaluation functions were studied,and the function with the best performance was selected through experiments.In view of the small field of view of the microscope,the camera was calibrated using a grating ruler,and the pixel equivalent of the system was obtained.Secondly,the research algorithm implements tool tip wear detection and tool tip arc measurement.Firstly,the image of the tool tip is filtered and noise-reduced.In the tool tip wear detection,the image acquired under the coaxial illumination is contrast-stretched,and then the threshold segmentation algorithm based on Gaussian smoothing and the connected domain labeling algorithm are used to obtain a decentralized image.The binarized image finally achieves accurate identification of the worn area according to the shape and position features.In the arc measurement of the tool tip,the image of the edge of the tool tip was obtained by using threshold segmentation and morphological processing on the image collected under backlight illumination,and then the edge detection algorithm was used to quickly extract the sub-pixel edge of the tool tip,and then through the edge segmentation and edge The fitting algorithm obtains the fitted tip arc,and the arc radius and center coordinates are measured.Finally,the software interface of the optical tool setting device is compiled to realize the real-time collection and processing of the tool tip image.Finally,in order to reasonably control the tooling error according to the accuracy requirements of the profile,turning simulation was carried out to realize the morphology prediction.The forming principle of non-rotation symmetrical surface is analyzed,and then the geometric precision of ultra-precision lathe is modeled using multi-body system theory.Based on the kinematic model of the machine tool,the tool tip trajectory is obtained.After that,a simulated turning surface was generated according to the principle of tool tip contour re-mapping,thereby predicting the effect of tool setting error on the accuracy of the workpiece profile.Finally,the interface of the simulation system is designed in Matlab to facilitate human-computer interaction.