Research On Surface Quality Detection And Analysis For A3Steel In High-speed Cutting

Abstract：The dissertation is supported by National Natural Science Fundation ofChina (No.50775210). The present work dedicates to the research on the mainfactors of influencing workpiece surface quality by quality tools. For themain influencing factors such as cutting force and cutting temperature, adetecting scheme of high-speed cutting dynamic temperature and cuttingforce was designed by thin-film thermocouple temperature sensor andpiezoelectric three-dynamometer, and the surface qualit y characteristic wasalso detected. The main factors of high-speed cutting workpiece surfacequality were analysed through experiments, and the basis for improvingproduct surface quality in high-speed cutting process was provided.High-speed cutting is a new technology in the manufacturing technology,and it has been widely used in machinery manufacturing industry. Becausethe cutting speed substantially increases, the most obvious benefit is toimprove the efficiency of cutting, and it also can achieve high-qualit yprocessing. Cutting temperature and cutting force are main factorsinfluencing cutting surface quality, and their change rule is the importantcontent for researching cutting principle and parameters. The main worksdedicate to:(1) The cause analysis of affecting surface quality. Quality tools wereused to determine the surface roughness as the main surface qualit ycharacteristics indicator. The main influencing factors of surface roughnesswere analysed. The cutting force and cutting temperature wer determined asthe main influencing factors.(2) Design the cutting temperature and cutting force detecting system.The detection system can monitor cutting temperature and cutting force whencutting the workpiece. The detection system included temperature and forcesensors, signal conditioning amplifier, signal display and storage. (3) A multi-layer thin-film NiCr-NiSi thermocouple sensor wasproduced. It included magnetron sputtering NiCr-NiSi film and chemicalvapor deposition Si3N4insulating film. The adhesion of thin-filmthermocouple was tested. Static and dynamic calibration for the filmthermocouple sensor was conducted.(4)The LC-1type of cold junction compensation and signal conditioningfor thin-film thermocouple was developed. It measured the ambienttemperature into a voltage to achieve the thermocouple cold junctioncompensation by AD590temperature sensor.(5) A3steel orthogonal cutting experiments, monitoring the cutting forceand cutting temperature, detecting the surface roughness of steel A3. Theexperiments showed that the impact of cutting speed on cutting temperaturewas maximum, cutting depth is the greatest impact on cutting force and thefeed had the greatest impact on the surface roughness.(6) High-speed cutting experiments, focusing on the analysis of theimpact on surface roughness. Cutting temperature and cutting force had amajor impact on surface roughness, and the choice of cutting parameter wasproposed.