The Perfect Custom Rubber Moulding: Manufacturing & Application

Rubber mouldings come in various shapes and sizes, and can be manufactured in a number of ways and from different materials. To obtain the right moulding for your job, you need to be aware of how they will be used and any challenges they will need to withstand.

What is Custom Rubber Moulding?

Rubber moulding produces a number of rubber products that can be of different shapes and sizes. For each one, the rubber is heated until it is malleable and then put into a mould that has the required shape and size. Once the rubber cools, it sets hard so it retains that shape.

Rubber mouldings can be obtained as standard products that have a set size and shape, and are made from a particular material. These products are available relatively cheaply but are only designed for generic products where precision may not be too critical.

Custom rubber mouldings are designed and manufactured specifically for a customer and product. A unique mould will be created for each one and these mouldings have to meet particular criteria. They are essential when absolute accuracy and reliability are needed and the product has to withstand certain conditions. They are intended to meet specific performance requirements and involve a manufacturing process that is largely bespoke.

The Manufacturing Process: From Design to Production

Since each custom rubber moulding has to satisfy particular needs, the manufacturing process has to follow defined steps:

• Design of the mould, which will determine the finished size, shape and characteristics of the moulding, therefore it is custom-made to meet the specification exactly. The mould may be made to produce one product or multiple products and is usually made from metal.
• Material selection, the chosen rubber compound has to be capable of withstanding operational conditions such as high pressure or extreme temperatures while retaining the necessary elasticity and having required durability.
• The moulding process, which will vary depending on the characteristics of the finished moulding, including its size and shape, and the number of mouldings to be manufactured.
• Finishing processes that can include trimming and polishing to achieve the required functionality and appearance.

Selecting the Right Rubber Material for Your Needs

Selection of the rubber material is a crucial step since it must have the necessary elasticity and durability for the process and must also be able to withstand operational conditions such as high pressure or temperature, or the presence of specific chemicals. Choose a suitable material based on its proposed use:

• Natural rubber has high tensile strength, is resistant to tearing and has excellent elasticity. It has a good compression recovery but can crack or degrade with exposure to natural light and can be more expensive than synthetic products.
• Nitrile is a synthetic rubber that can resist high temperatures and various oils and greases, and has good mechanical properties.
• EPDM is a versatile synthetic rubber that doesn’t deform when subjected to extreme heat and has excellent resistance to weathering and chemicals.
• Neoprene is a synthetic rubber that resists UV rays, chemicals and oil, and is durable.
• Silicone rubber can withstand extreme temperature ranges and can be any colour but has poor tensile strength and can tear.
• Viton has excellent chemical resistance and provides high quality sealing.
• PVC resists chemicals and is relatively inexpensive.
• Styrene-butadiene is cheaper than natural rubber, has high abrasion resistance but does not resist UV rays or chemicals well.

Many materials can be obtained in solid or sponge rubber format, depending on the application. Additives provide higher resistance to extreme temperature, pressure and chemicals.

Common Manufacturing Methods

Different rubber moulding processes are used and depend on the intended application:

• Compression moulding – Rubber goes into a heated mould, which is then closed and compressed so the rubber fully fills the mould. It is mainly used to produce relatively large and simple products made in small quantities.
• Injection moulding – Molten rubber is injected under high pressure into a mould cavity where it cools and solidifies. The process is highly automated and is used for complex shapes requiring high precision, which are produced in large volumes.
• Transfer moulding – Heated rubber is forced into a closed mould at high pressure. The process offers great control over material flow and accuracy of products, and is often used for small to medium production runs.

Diverse Applications Across Various Industries

The adaptability of custom rubber mouldings means they are used in a wide range of industries for a number of applications. These include:

• Bushings, O-rings, gaskets and seals for use in engines in the automotive industry where they prevent leaks and friction.
• Isolators to reduce vibration in aerospace equipment and seals and gaskets in aircraft engines and hydraulic systems.
• Seals for pipelines and other equipment, and packing rings in wellhead and drilling gear in the oil and gas industry.
• Seals for watertight enclosures in shipping.
• To provide airtight and watertight seals for medical equipment.

The list is long and growing because rubber mouldings are sufficiently versatile for a host of uses.

Quality Control and Assurance in Rubber Moulding

Many custom rubber mouldings are required to operate in extremely harsh environments and have to do this completely reliably. Industries such as aerospace cannot afford failure while food and pharmaceutical processing need to ensure complete hygiene at all times so there is no contamination.

To ensure reliability and durability, strict quality control procedures have to be followed in the manufacture of custom rubber mouldings. Crucial to this are the construction of the mould and the selection of suitable materials, since these are fundamental to the outcome of the rubber mouldings

Every step of the process has to be thoroughly checked and controlled to ensure the customer’s specification is precisely adhered to. This will ensure each moulding performs exactly as it should and that there are no failings in the customer’s equipment or processes.

Partnering with a Reputable Manufacturer

The chances of your rubber mouldings being as reliable as you wish and meeting your specification will be greatly increased by having a manufacturer that is experienced in their use in various industries and applications. At Gulf Rubber, we specialise in producing a variety of rubber products for a wide range of applications.

We work closely with our customers, listen to their needs and produce custom rubber products that exactly meet their specification. We survive and prosper based on our reputation for providing high-quality rubber products that are durable and reliable in all conditions. 

Check out what we do and get in touch to experience it yourself.