Research On Key Techniques Of High Precision Form Measuring Instrument

With the development of the manufacturing technology, the requirement of the mechanicalindustry for the manufacturing precision increase gradually, as while the requirement for theprecision of the measuring instrument is higher. The form measuring instrument is a kind ofprecision instrument for measuring the form error(such as cylindricity, roundness, axisstraightness and generatrix) and some of the position error(such as co-axiality, verticality, etc.) ofcylindricity parts. This paper proposes the study of the key techniques of high-precision formmeasuring instrument, which includes the machine structure design of the instrument, themanufacturing and assembly process, the measurement method, data processing method and soon.According to the characteristics of the different structures of the instrument, the structure ofthe rotating turntable is selected. The measuring method adopts the contact measurement and themeasuring path selects the section method.Through analyzing and comparing the different structures of the turntable and guideway,the porous restriction aerostatic table and guideway are selected on the instrument, and theporous material adopt graphite.In this paper a kind of thrust bearing and radial bearing structure of table was designed forthe form measuring instrument, this kind of structure could reduce the eccentric distance andimprove the table’s running accuracy. The relation between its parameter and static performanceof this kind of aerostatic bearing is got through analyzing using the software FLUENT. The staticcharacteristics of the guideway of different structures were analyzed with the software based onthe finite element method, and then the optimum design was obtained by comparing thedeformation. The overall structure of the guideway adopts the closed-box structure, which hasgood global symmetry and high running precision. For the volume of the instrument in thispaper is small, a kind of small adjust workbench support suitable for application in themeasuring instrument was designed, this kind of workbench has the feature of compact structure and high adjustment precision.The manufacturing and assembly process of the key component were formulated in thispaper. It also analyzed the source of the error and the data processing method, and the guidewaywas calibrated by using standard cylindrical carpenter’s rule.