The following lists “good manufacturing practices” for using adhesive to bond small bearings.

1. CLEAN MATING SURFACES

Mating surfaces must be cleaned and free from grease or oils. Since bearings will have been lubricated, it is particularly important to clean the outer surfaces of the rings. In some cases, bearings are available pre-cleaned at the factory (see Bearing Part Numbering System for applicable codes).

2. USE PRIMER IF NECESSARY

Anaerobic adhesives require at least one mating surface to have some porosity to oxygen. If coated or anodized materials are used, then a suitable primer will be necessary. The use of a primer may also improve bond strength when dissimilar materials are used in bearings and mating components. See adhesive manufacturers specifications on primer use.

3. CONTROL THE AMOUNT OF ADHESIVE APPLIED

If possible, use an electronic dispenser that delivers an accurately controlled amount of adhesive. This amount should be set to minimize excess adhesive outside the adhesive groove(s). Distribute the adhesive evenly around the circumference of the part.

4. SET-UP TIME

The bonded assembly needs to be left undisturbed for enough time that the adhesive “sets up” sufficiently to retain the components in place. This period is specified by the adhesive manufacturer and is different from the time to achieve full cure.

5. REMOVE EXCESS ADHESIVE

Anaerobic adhesive sets in the absence of air. Any excess adhesive left on the outside of the mating surfaces will not set properly and represents a hazard to the bearing as it may migrate into the raceways, causing damage. All visible excess adhesive should be wiped off after the part has setup. Alternatively, an ultraviolet curing adhesive can be used, where exposure to a strong UV source after set-up will cure any remaining adhesive.

For more detailed information contact SWC’s Application Engineering Department.