If the radial runout of the spindle is measured after the bearing has been installed in the mainframe, a certain variation in the measured value of each revolution can be found; when the measurement is carried out continuously, it can be found that after a certain number of revolutions, the variation will be approximately repeated. The number of revolutions required for the variation to recur approximately represents the "quasi-period" of cyclic rotational accuracy, and a large change in value within the quasi-period is considered poor cyclic rotational accuracy.

The cyclic accuracy of the spindle can be improved if the spindle is properly pre-loaded and the speed is gradually reduced to close to the obligatory speed in order to implement the "break-in" effect of the bearings.

The main factors used for adjustment are installation, use and maintenance, maintenance and repair, etc. in accordance with technical requirements. According to the technical requirements of bearing installation, use, maintenance and repair operation of the bearing contact load, speed, temperature, vibration, noise and lubrication status monitoring and inspection, found abnormal immediately to find the cause, adjustment, so that it returns to normal. Installation conditions are one of the factors that use the bearing is often caused by incorrect installation of the package between the various parts of the state changes in the gravity of the primary factors in the abnormal operating conditions and early termination of life

1, contact fatigue failure

Contact fatigue failure refers to the bearing working surface by the action of alternating stress and failure. Contact fatigue spalling occurs in the bearing working surface, often also accompanied by fatigue cracking, first from the contact surface below the larger alternating tangential stresses, and then expand to the surface to form different spalling shape, such as point-like for pitting or pockmark spalling, spalling into small pieces of said shallow spalling. Due to the gradual expansion of the spalling surface, and often to the deep expansion, the formation of deep spalling. Deep spalling is the fatigue source of contact fatigue failure.

2、Abrasion loss effect

Abrasion loss effect is the relative sliding friction between the surface leads to its work surface metal continuously wear and failure. Continuous wear will cause gradual damage to the bearing parts and eventually lead to loss of dimensional accuracy and other related problems. Wear may affect the shape change, with the gap increase and work surface shape change, may affect the lubricant or make its pollution to a certain extent and cause the lubrication function completely lost, thus making the bearing lose rotational accuracy and even can not be normal operation. Abrasion is one of the common failure modes of all types of bearings, according to the form of wear can usually be divided into the more common abrasive wear and adhesive wear.

1) Instrument detection　　

The use of instruments such as the iron spectrometer or SPM or the new VIB05 detector to determine the operating condition of the bearing to determine whether it should be maintained or replaced is just one of the more convenient and reliable methods.

For example, when using the VIBO5 tester, a new microprocessor-based machine condition tester with vibration detection, bearing condition analysis and infrared temperature measurement. It is easy to operate and automatically indicates status alarms, making it ideal for on-site equipment operation and maintenance personnel to check the condition of equipment, identify problems in time and ensure normal and reliable operation.

The use of such an instrument can make full use of the working potential of the bearing, timely will be bearing warranty, and can avoid failure, more suitable for young staff to make up for their lack of experience.

2) Manual inspection

In places where the above-mentioned instruments are not available, a listening tool similar to a medical stethoscope can be used to carry out the test. Experienced operators can also use tools such as round rods or spanners against parts of the machine housing that are closer to the bearing and use their ears to listen to the running sound of the bearing through the tool.

A normal bearing running sound should be uniform, smooth and not harsh, while an abnormal bearing running sound is intermittent, percussive or harsh.