Assemblies and Tolerances

Dimensional tolerances are wider for porous plastics than for solid plastic parts. Fortunately, porous plastic parts are resilient, allowing for an interference fit. This eliminates the need for gaskets in many applications. Therefore, the inside diameter of a porous plastic part can be smaller than the mating diameter it fits over; a plug or disc may be force-fit into a smaller hole; and a porous plastic sheet may be compressed between two rigid surfaces.

The higher the void volume, the more resilient the structure. The level of resiliency in decreasing order, by polymer, is polyvinylidene fluoride (PVDF), polypropylene (PP) and polyethylene (PE).