Miniature bearings are a category of rolling bearings with a nominal outer diameter less than 26 millimeters. Among them, miniature ball bearings with a metric outer diameter less than 9 millimeters are referred to as ultra-miniature bearings in China. The main materials include carbon steel, bearing steel, stainless steel, plastic, and ceramics. The inner diameter can be as small as 0.6 millimeters, and common specifications include metric 68, 69, 60 series and imperial R series miniature deep groove ball bearings. Derivative structures involve types such as those with ZZ steel plate dust covers, RS rubber seal rings, Teflon seal rings, and flange ribs [1] [3]. These bearings consist of inner and outer rings, bearing balls, cages, and other components. Domestic manufacturers often adopt an assembly production model with outsourced rings. They are mainly used in high-speed equipment such as micro motors, instruments, hard disk motors, and computer cooling fans, and are gradually expanding to fields such as medical devices, industrial robots, and autonomous driving [2-3]. Over 40% of failure cases are caused by contaminant intrusion, and proper installation and protection can reduce the risk of damage [2]. With the increasing demand for miniaturization in downstream fields, the industry is trending towards customized development and flexible production transformation [
