① If the base material is very soft, the surface of the base mother board material will be damaged during the process of screwing in the bolts or screws. By using washers, this squeezing force can be distributed in a larger area to avoid damage to the surface of the motherboard.

② If the base material is very soft, and the periphery of the hole where the fastener is installed has been damaged, the problem of pull-through failure may occur during the process of screwing in the fastener. This is because in most cases, the application of The force during the tightening process is sufficient to pull the fastener through the material mother board, and the presence of the gasket helps to generate a smaller build-up pressure.

③When the surface of the motherboard into which the bolts or screws are screwed is not smooth and flat, the heads of the fasteners are likely to be stuck. By using washers, the surface of the bolts or screws can be ensured to slide and make installation easier.

④ Some washers are designed with a special structure to prevent the nut from loosening. We commonly call this type of washer a lock washer, and there are many types of structures, such as open type, star type, wave type, and so on. This type of lock washer needs to be used in conjunction with a nut.