Development Of A Versatile Non-contact Roundness Detecting Instrument

Oilless bearing is an important industrial parts, and the roundness error of itsinternal&external surface will directly affect its performance of some aspects, such as:self-lubricating ability, working stability, service life and so on. However, because of itsspecial processing technology and smaller size, some traditional contact roundnesstesting equipment, for example, roundness measuring instrument and three coordinatemeasuring machine are not suitable for this task.This dissertation come from the project commissioned from enterprise, aim todevelop a versatile non-contact roundness detecting instrument. By integrating imagemethod and laser triangulation method, the instrument can realize accurate detection ofroundness error of oilless bearings as the enterprise’s requirement.Detailed researchcontents and results are as follows:1.According to measuring principle of image method and laser triangulationmethod, complete the overall structural design of the instrument’s hardware andsoftware, carry out error-source analysis of the measurement system.2.Due to measurement requirements and the results of error analysis, complete theselection of some key components and the design of mechanical structure.3.To automate the detecting instrument, develop a monitoring and control softwaresystem. Present a new algorithm of roundness error evaluation under numeroussampling points. Simulations prove that the optimal number of sampling points is about100~200when evaluation.4.Carry out the calibration experiments to achieve characteristic curve ofmagnification ratio in image measurement system, fitting a linear relationship betweenthe grating reading and magnification ratio. With the help of a standard ball,successfully isolate and correct the main system error caused by radial runout of the turntable. Compared with detecting results of Talyrond365roundness measuring instrument,the developed instrument’s measurement uncertainty meets the design requirements.This developed instrument isn’t the special detecting instrument just for oillessbearing, it is equally applicable to measure other workpieces’roundness error.