Surface coatings optimise O-ring performance

Edited by the Engineeringtalk editorial team Apr 29, 2002

Freudenberg Seals and Vibration Control Simrit reckons it has the right process for optimising the surface characteristics of O-rings.

Functional boundary conditions and assembly-related requirements often make conflicting demands on O-ring seals.

This discrepancy can be minimised using modern surface treatment processes which allow basic elastomers and a separate surface coating to go hand in hand.

Together, they ensure an optimum set of profiles both in terms of economic assembly and reliable O-ring sealing.

The sealing effect of an O-ring is basically the result of an axial or radial deformation of its cross-section once it is installed.

This means that the correct layout of the housing and an optimum adaptation of the material to suit the medium to be sealed are of the utmost importance.

The smooth surface of the O-ring is advantageous for many static sealing problems.

It is closed homogeneously.

The selection of the right elastomer materials makes the O-ring resistant to chemical and mechanical corrosion.

In order to allow for automated seal assembly, the easy separation of O-rings is absolutely essential.

In other words, for ease of assembly, it is important that they do not stick together.

Operating conditions can also make demands on the O-rings: dynamic loads, start-up or emergency running properties or the lack of stick-slip are necessary for many applications.

This discrepancy between functional and assembly-related requirements can be eliminated using specific surface treatment.

Depending on the profile of requirements in question, which might, for example, include the following demands: improved assembly, prevention of slip-stick, improved emergency running properties, the ability to withstand brief dynamic loads or the ability to allow for high dynamic loads.

Freudenberg Seals and Vibration Control Simrit reckons it has the right process for optimising the surface characteristics of O-rings.

The surfaces of the O-rings can be treated with: powders, special greases and oils, emulsions and varnishes, or be chlorinated in aqueous solutions.

Thanks to these surface treatment processes, specific O-ring seal functions can be optimised.