Surface defect detection based on capacitive probe for bearing ball

According to the characteristics of the bearing ball surface defects, the capacitance probe detection system was adopted for measuring. Due to the sensitive measurement area of capacitance sensor is certain sizes of equivalent plane, the average effect eliminates the influence of microcosmic geometric feature. According to the standard of the ball bearing parameter changes, we put forward a dynamic threshold algorithm for defect detection. The algorithm combined the whole characteristic value with local one, by using differences between the normal surface measurements and defective surface detection to find defect. And to Φ 18.2562mm stainless steel bearing ball as an example, the normalization processing was done for data measured along the meridian, through the data distribution of probability density function, it intuitively shows the measurement value distribution characteristics of qualified bearing ball and defective one, so we can do effective separation for normal data and defect data.