In applications where the components are plastic, a compression limiter is necessary to prevent creep or stress relaxation reducing the frictional load between the threaded joints.
Similar to inserts, compression limiters are used to ensure the integrity of the bolt union in a plastic assembly. As the bolt is screwed in to achieve the desired friction between the threads, the plastic is compressed.
The compression limiter absorbs the force generated during tightening of the bolt and insulates the plastic from excess compressive load. Without the compression limiter, plastic materials would soften causing loosening and seal failure. It therefore ensures that the union remains intact throughout the life of the product.