The bearing normally can be used up to the end of the rolling fatigue life if handled properly. If it fails earlier, it may caused by improper mounting, mishandling, poor lubrication, entry of foreign matter or abnormal heat generation. Considering possible causes of bearing failure and damages according to the condition of the machine on which the bearings failed and taking countermeasures is very important to prevent the recurrence of similar problems.

Following types of damage typically encountered are presented in the table below.

Damage type	Illustration of damage conditions	Possible Causes	Solutions
Flaking		● Over and excessive load ● Improper handling and    mounting ● Poor shaft or housing    accuracy etc. ● Unsuitable bearing clearance ● Installation error etc.	● Find out the cause of    the heavy load ● Examine operating    conditions ● Improve the mounting    method ● Check the precision of    shaft and housing ● Check the bearing    internal clearance
Speckles		● Ingress of foreign particles	● Improvement in sealing ● Improvement of the    operating environment    if possible ● Filtration of the oil or    grease
Cracking		● Excessive load ● Excessive impacts ● Rapid cooling ● Excessive interference ● Overheating by creeping ● Very loose fit ● Large flaking etc.	● Find out the cause of    very large load ● Improve the installation    process ● Correct the interference ● Prevent the creep
Rust and Corrosion		● Ingress of water or corrosive    material (such as acid) ● Condensation of moisture    contained in the air ● Poor packaging and storing    conditions ● Handling with bare hands etc.	● Do not use bad quality    varnish ● Dry the varnish properly     with sufficient time ● Improvement in sealing    effect ● Careful handling of    bearing
Mounting Flaws		● Inclination of inner and outer    rings during mounting or    dismounting. ● Shock load during mounting or    dismounting.	● Use appropriate jig and    tool ● Avoid a shock load by    use of a press machine ● Center the relative    mating parts during    mounting
Eletrical Corrosion		● Electrical potential difference    between inner and outer rings ● Electrical potential difference    of a high frequency that is    generated by instruments or    substrates when used near a    bearing	● Design electric circuits    which prevent current    flow through the bearings ● Insulation of the bearing
Seizure		● The grease’s maximum working    temperature is lower than    the actual temperature and    the grease get failure. ● Excessive rotational speed ● Dissipation of heat generated    by bearing is not enough. ● Clearance too small. ● Excessive load (or preload) ● Installation error etc.	● Selection of suitable     lubricant grease ● Improve dissipation of     heat from the bearing ● Improvement in clearance     and preload ● Improvement in operating     conditions
Fracture		● Impact during mounting ● Excessive load ● Poor handling such as dropping	● Improve the mounting    method (shrink fit, use    proper tools) ● Reconsider the load    conditions ● Provide enough back-    up and support for the    bearing rib.
Fretting		● Poor lubrication ● Vibration with a small amplitude ● Insufficient interference	● Use a proper lubricant ● Apply a preload ● Check the interference    fit ● Apply a film of lubricant    to the fitting surface
Cage Damage		● Poor mounting (Bearing    misalignment) ● Large moment load ● Shock and large vibration ● Excessive rotation speed,    sudden acceleration and    deceleration ● Poor lubrication ● Temperature rise	● Check the mounting    method ● Check the temperature,    rotation, and load    conditions ● Reduce the vibration ● Select a cage type ● Select a lubrication    method and lubricant