Research On The Position Detection For Nose Waveness Of Diamond Cutting Tool Based On C_LVDT

Natural diamond cutting tools are widely used in ultra-precision machining,and have unique advantages in ultra-smooth surface processing.The machined surface roughness can reach several nanometers.In high precision surface machining,the nose waviness of the diamond cutting tool is one of the key factors to determine the surface quality.Therefore,it is necessary to strictly control the nose waviness of the diamond cutting tool tip.According to the current domestic and foreign research,there is no research on the position detection for nose waviness of diamond cutting tool.It is impossible to detect the nose waviness in machining process.Therefore,in this thesis,the position detection technology on the nose waviness of diamond cutting tool is discussed.Based on that,a system of a high-precision position detection for nose waviness of diamond cutting tool is established.First of all,the characteristic is utilized that the rotary of the pendulum shaft on the grinding machine is coincide with the center of diamond cutting tool circular arc,this thesis establishes a position detection system for the measurement of the nose arc of the diamond cutting tool,which is based on a C_LVDT capacitive displacement sensor,designs the hardware and software of the system,and analyzes the accuracy of the detection system preliminarily.On the basis of analyzing the limitation of the traditional least square circle method in short arc fitting,the optimization process of least square circle method is improved,and the least square circle method based on mathematical statistics is put forward.The new method based on mathematical statistics and the least square circle method could inhibit the eccentric phenomenon of short arc fitting effectively.The detection and evaluation software for the system is designed,which can realize the position detection and evaluation of the nose waviness of diamond cutting tool.Based on that,the workload of subsequent data processing is reduced.Secondly,how the angle,radius of the diamond tip and the roughness,waviness error influence the measuring accuracy of the nose waviness is analyzed by the method of theoretical modeling.A measurement and calculation model of diamond tip is established by using Mat lab.On the basis of the software above,the difference of the measuring result among different diamond tip measuring the surfaces modeled by sinusoidal with roughness and small scale waviness and the real profile of cross section measured by AFM is gained by simulation calculation.By analyzing the spectral of the simulated measurement data,the influences of the variables mentioned above on the measurement accuracy of nose waviness are investigated.A simulation software of diamond tip is designed,which provides a theoretical basis for the selection of the tip,which is used to measure the nose waviness of diamond cutting tool during the experiment below.In addition,through the analysis of characteristics of rotary motion pendulum shaft grinding machine and traditional method to separate rotating shaft error,a new separation model for pendulum shaft rotating is established,which is called ‘Multipoint bidirectional method'.The eccentric installation of the standard ball and misalignment of the sensor relative to the equator of the standard ball were analyzed quantitatively.It has been reviewed that the independence of the pendulum shaft error and the feasibility to separate the installing eccentric error by the first harmonic filter.A detection system for the pendulum shaft rotating error of a diamond tool grinding machine is built,and the software of the system is complied.Using the least square method evaluates the pendulum shaft rotating error and standard ball roundness error,separated by the ‘Reverse method' or the ‘Multipoint bidirectional method.Last but not least,position detection measuring experiments on the nose waviness of diamond cutting tool are done,including the design of diamond tip,the verification of the pendulum shaft rotating error of the grinding machine.Through the contrast experiment of profile meter and radius amplitude measuring instrument,the feasibility and accuracy level of the system built in this essay are verified.The experimental results show that the location detection technique of diamond tool nose waviness is practical and reliable.