基于菲涅耳衍射的钢珠直径及圆度误差的测量

Measurement of Steel Ball Diameter and Roundness Error Based on Fresnel Diffraction

针对目前钢珠类球形部件的直径和圆度测量系统较为复杂、测量仪器成本较高等问题,提出一种基于菲涅耳衍射测量钢珠直径和圆度误差的方法。利用圆点标定板校准圆球菲涅耳衍射的峰值点和投影边缘的关系,根据光强分布曲线测量钢珠直径及圆度误差。实验结果表明,在不考虑钢珠表面的漫反射及散射的情况下,对直径为毫米级别的钢珠进行测量时,其直径和圆度误差的测量不确定度分别在0.0031 mm(置信水平95%)和0.0046 mm(置信水平95%)以内。该测量系统的组成简单,无需额外的光学系统,且成本较低。

At present,measurement systems for measuring diameter and roundness of steel-ball-type spherical parts have significant drawbacks,such as complexity and high cost.To overcome these challenges,we propose a method based on the Fresnel diffraction.It is found that the diameter and roundness error of a steel ball can be measured according to the light intensity distribution curve,based on the relation between the peak point and projection edge of spherical Fresnel diffraction,which is calibrated using the dot calibration plate.Experimental results show that the measurement uncertainty of the diameter and roundness error of a millimeter steel ball is less than 0.0031 mm(confidence level is 95%)and 0.0046 mm(confidence level is 95%),respectively,without considering the diffuse reflection and scattering of the steel ball surface.Our proposed system is easy to realize,cost effective,and does not need an additional optical system.