A novel lapping method for ultraprecision cylindrical rollers based on precision evolution

Abstract

The geometrical precision of cylindrical rollers is a crucial factor influencing the rotation accuracy of the cylindrical roller bearing and limits of the rotation speed, load bearing capacity and serving life of the bearings. A novel lapping method with a circulating system for batch machining of ultraprecision cylindrical rollers is presented based on the principle of precision evolution. The variations of roller diameter and roundness are improved due to the effect of selective material removal. That is, more material is removed at the convex position for a single roller, and also for the balls with larger diameters, because higher stress concentrated in these areas will lead to plastic deformation and failure. Self-rotation of the rollers was realized by the application of electromagnetic force. Batch lapping of cylindrical rollers was carried out on a newly developed lapping system for approximately 500 rollers. After lapping 90 cycles, the variation of roller diameter for the randomly selected ten rollers, roundness and surface roughness were 0.76 µm, 0.4 µm and 14.93 nm, respectively. Additionally, the variation of roller diameter of 100 randomly selected rollers was 0.97 µm. This geometrical accuracy is higher than that of the highest standard class G1. This method realized the machining of ultraprecision rollers without size sorting and provided a solution for machining rollers with higher diameter consistency than that of the normal industrial manufacturing method. Based on the principle of precision evolution, this work provides a novel machining approach for batch machining of high precision cylindrical rollers.