Compression limiters are a type of insert or bushing designed to protect plastic parts from damage by limiting the compressive force from assembly bolts. The tightening of bolts causes a load to be transferred to the plastic substrate, resulting in cracking and creeping, many times leading to part failure. Compression limiters are designed to be inserted into a hole before the bolt is inserted and tightened.
Compression limiters may be manufactured as solid or split down one side. They may also have knurled edges for the purpose of retaining the insert in the bolt hole. Selecting compression limiters requires analysis of the hole diameter, fastener diameter, and overall insert length.
An assortment of solid and split-seam compression limiters.
Image credit: DesignWorld/SPIROL