High-pressure O-rings are among the most common and widely used forms of seal. As manufacturers and users are aware, they are used in a wide range of sectors to prevent fluid leaks in hydraulic and pneumatic systems.

These special ring-shaped gaskets are used to seal joints between two pipes or surfaces in electronics, mechanics, hydraulics, chemistry and even in the food industry.

O-rings play a crucial role in ensuring the correct functioning of the mechanism in which they are inserted. How can high-pressure O-rings be guaranteed to provide quality and durability?

At GBS we have been manufacturing O-ring moulds for over 30 years and have extensive knowledge of all types of high-pressure rings, the most suitable materials for each application and the most appropriate moulding techniques.

These are factors to consider when purchasing or manufacturing O-rings.

Sector and position of use; static or dynamic sealing?

The field of application of high-pressure rings is so wide that it is not possible – nor would it be professional – to claim that one type of O-ring is of better quality than another. Never more so than in this case is the position of use crucial.

In the case of static applications – those in which there is no relative movement between the surfaces to be sealed – rings can withstand higher pressure. In this case, however, it is essential to take into account the deformation that the O-ring undergoes – i.e., the crushing value – which depends above all on the material used.

Wear, and the condition of the surfaces with which the O-ring is in contact should also be assessed. If not properly prepared, these can damage the gasket and compromise the seal.

In dynamic sealing, the O-ring may be able to withstand lower levels of pressure. This is due to friction wear, rises in temperature and problems related to extrusion. High temperatures, in particular, may damage the ring material to such an extent that the seal it provides is impaired.

Choice of material; hardness and heat resistance

The production process for high-pressure rings is comprised of several steps; one of the most important is the choice of material.

 This varies depending on the requirements of application and the fluids or gases with which the seal will be in contact. In any case, the most common materials are EPDM rubber, nitrile rubber, fluorocarbon rubber and silicone.

Producing a material from scratch, designed exclusively for the particular application required, is another option. Some specialised companies offer this service in collaboration with industry R&D laboratories.

Choosing the right material is crucial in order to:

• reduce the risk of extrusion – materials with higher degrees of hardness are more suitable for high-pressure applications and less prone to extrusion.
• ensure a perfect seal – more elastic materials need to be pressed harder in order to maintain the seal.

It is also crucial to take into account the temperature – both maximum and minimum – to which the high-pressure O-rings will be subjected. High temperatures cause the material to expand, rendering it susceptible to deformation and extrusion. Low temperatures cause the material to contract, compromising the seal.

All these factors – and many others – must be considered and monitored throughout the design and production of O-rings.

When fully customised O-rings are required, we at GBS step in by designing and supplying customised moulds based on the technical characteristics of the items to be manufactured.

Design features and mould quality

Excellent O-rings are made from excellent moulds. The mould is an often underestimated factor, yet they are fundamental for creating high-performance products of perfect quality, as well as for optimising the use of resources.

In manufacturing a customised O-ring mould, it is important to assess the size of the products to be moulded and the number of products we want to obtain with each moulding cycle – also in terms of material handling capabilities. Extreme care must also be taken when defining the positioning of the mould closure lines.

In general, design and production are characterised by many factors, and these can only be properly overseen by experienced CAD designers and skilled workers.

GBS high-pressure ring moulds

 O-rings are among the most popular seals, but, as those in the industry know, this by no means renders them standard products.

At GBS, we have been designing moulds for high-pressure rings and for technical rubber and thermoplastic items since 1987, and we now have UNI EN ISO 9001 and ISO 45001 certification.

For our Clients, our technical specialists act not only as a supplier, but also as a partner on hand to assist them from design (based on drawing, sample or mathematical model) through to production.

We produce moulds up to 1400 mm x 1400 mm for both injection and compression moulding, with an optimised footprint layout to achieve the best balance of quality and production demands.

In addition to moulds for O-rings, our production line offers moulds for technical and rubber-metal articles, as well as thermoregulated injection moulds.

Do you have a question about our products, or would you like to develop a customised mould? Contact us for information or a quote.