Study On The Methods Of Multiple Optical Fibers For Steel Ball Surface Defects Inspection

The steel ball is one of the important part of the rolling bearing, and its quality plays a keyrole on the service life, the motion accuracy and rotation performance, especially, which has anobvious influence on the bearing function characteristic. It affects the surface capacity of therotating part and fatigue strength, moreovers, it has very important requirements for thematching performance on the matched part, lubrication performance and abrasion resistanceand many other aspects. In the analysis of ball bearing defect factors, because of the failureforms caused by the steel ball surface defects up to70%. To test the steel ball surface defects isnot only the key factor of the ball bearing quality, but also the key factor to guarantee the goodquality of steel ball surface. A new kind of technology in our country, to develop the steel ballsurface quality testing instrument with the domestic independent intellectual property rights, isurgently required in improving the detection precision and accuracy, reducing equipmentpurchase cost and dependence on foreign equipment.In this paper, the steel ball surface defects of optical fiber detection method study iscarried out in a series of fund project funding. This topic is involved in Enterprises EntrustProject, Doctor Fund of Jinan University (XBS0854), the National College Students’Innovative Entrepreneurial Training Project (201210427022), the Colleges and Universities inShandong Province Project (J10LD22) as well as Shandong Scientific Research Foundationfor Excellent Young Scientists (BS2010ZZ001), etc. With steel ball surface defects as theresearch object, according to the rough surface scattering theory and double beam ratiomeasurement method, the optical fiber sensing technology is applied to the steel ball surfacedefects detection. In order to break the bottleneck of low efficiency and poor levels ofautomation, we want to develop a set of steel ball surface defects detection equipmentmoderate in price, fast and efficient.According to the standards of steel ball surface defects, analyzing the parameters andcharacteristics of the defects，which are classified as displacement defects and roughnessdefects, Optical fiber sensor is used to implement the defect characteristics.For the convenience of extracting the characteristics of steel ball surface defects, analyzing optical fiber arrangement of optical fiber sensor probe, determine the probe arraythat the center launch fiber surrounded by three laps receive fibers, using reflective lightintensity modulation optical fiber sensor to detect the defects of the steel ball. Based on thegaussian hypothesis, Spherical detection model of optical fiber sensor is established. Thefunction model derived from the geometric relationships. Using the matlab to simulate theinner/outer diameter of the fiber, the numerical aperture and the distance between transmittingand receiving fibers, according to the simulation curve determine the reasonable structureparameters of optical fiber sensor.Making an analysis and a design of ball surface defect detection signal processing systemincluding the modulated light source driver circuit, the photoelectric conversion circuit, thehead differential amplifier circuit, the infinite gain band-pass filter circuit and the windowfunction comparison circuit, which magnify the defect characteristics of the signal effectively,filter noise interference and improve the signal-to-noise ratio. Finally it completes defectcharacteristic signal acquisition and sents them to PC for processing.Making the sensor and the circuit board, Seting up the experimental platform, opticalfiber sensor can be used to make steel ball surface detection which verified by experiments.Studying the light intensity distribution of transmitting fiber, which is approximae for gaussiandistribution, demonstrate the correctness of the hypothesis and the accuracy of sphericaldetection model. Arranging roughness measuring experiments, which show that the opticalfiber sensor can be used to make roughness detection. Double beam comparison measuringdisplacement experiment shows that sensor can effectively separate roughness effect anddisplacement of the defects.Through the researches, initially set up a multiple fibers inspection system for steel ballsurface defects, lay the foundation for the development of the steel ball surface quality testingmachine.