Research On Influencing Factors Of Lapping Trace Uniformity On Rotated Dual-plates Lapping Mode

The accuracy of precision ball is the important guarantee for the structure and function of roundness measuring equipment,gyro,precision bearings,ball screws,ball guides and precision measuring instruments.Double rotation grinding method is used to grind high-precision balls which are put forward by the research center.The combination of internal and external wheel rotation speed can control ball's rotation angle,achieve full envelope of grinding track,ensure the lapping uniformity,and can be theoretically stable processing G5 level and above G5 level high precision balls.In order to further improve the double rotation grinding method to enhance the mechanical processing of dynamic control ability,give full play to machine ultra-precision balls.Guarantee of sphericity is more difficult in accuracy indicators,so this paper analyses factors which impact sphericity index deeply.Sphericity mainly reflects from the variation range and variation regularity of ball's spin angle,and presents by the uniform distribution of grinding track points.Therefore,This dissertation focused on firstly analyze several factors which impact rotated dual-plates uniformity as follows:balls slide at grinding process,uneven sliding goes against to the uniform distribution of grinding track points;reasonable ratio value of internal and external plate rotation speed in lower plate can ensure whole spherical envelope of the trajectory of grinding points in order to achieve uniform distribution of grinding track points;appropriate load can promote ball's full rotation which is conducive to grind evenly,however,overload will lower the ball's sphericity;in addition the beating,tilt and roundness error of lower plate are not conducive to grinding tracks evenly distributed;the analysis reveal that groove angle ranges in the 30°?60°is suitable to grinding and the best angle is 45°.In addition,It is important to establish a rotated dual-plates mechanism numerical simulation model in order to optimize the grinding parameters,the simulation research are as follows:the impact of the combination ratio of ball's diameter and grinding plate size which will affect the grinding uniformity,and find the best ratio range of reference parameters;lower plate's V-groove angle in rotated dual-plates mechanism impact the grinding uniformity and find the best angle of reference parameters;optimize the former speed curve of the internal and external plate in lower plate,and turn the curve from original triangular wave to a new speed curve gradually,so that the grinding track points will optimal and evenly distribute;furthermore create two evaluation methods to assess the spherical trajectory uniformity,one is triangle mesh method which using standard deviation as the evaluation index,another is ball appearance simulation method which using spherical deviation as the evaluation index.Removal of adverse effects,using the optimized processing parameters,rotated dual-plates can obtain expected results stably,verify the validity of theory and simulation analysis.