Both natural and synthetic rubbers can be manipulated into different forms, both simple and highly complex. Through a range of manufacturing processes, engineers within many sectors have turned to the durability and versatility of rubber to design and manufacture a range of industrial products for purposes including sealing, cushioning and impact reduction. One of the biggest benefits of rubber is its suitability for rubber moulding.
Nowadays, rubber mouldings and other rubber products are intrinsic to virtually every industrial sector, fulfilling a wide variety of different roles. A range of rubber materials can be used for rubber moulding, including commercial grade materials including EPDM, Natural rubber, Neoprene, Nitrile and Silicone, converted into rubber components such as gaskets, vibration isolation parts, mounts, washers, O-rings, and an extensive range of other products to suit different industrial applications.
Given that there are many uses for rubber mouldings, it’s important that designers and manufacturers choose the right rubber moulding process to suit their requirements.
Rubber Moulding Processes
It goes without saying that all rubber moulding processes require a mould in order for raw material to be converted to the desired shape. Moulds are manufactured from a design, produced using metals such as hardened steel that will maintain their shape to ensure the highest quality of finished product.
Two of the most common moulding processes for rubber compounds are compression moulding and injection moulding, both of which have their own advantages for different applications.
Compression Moulding
Compression moulding is a relatively simple rubber moulding process. Raw rubber compound is pre-weighed and the required amount is poured into the mould. The mould is then closed, and a combination of pressure and heat is applied in order to reshape the rubber. As the rubber is exposed to heat, it fills the mould cavity, and once it reaches the required temperature and pressure, it hardens (cures) to ensure that it will keep its shape when cooled.
As the compression moulding process is simpler than other moulding processes, one of the benefits is that the tooling is also simple and can be manufactured for a lower cost. This cheaper tooling is well suited for prototyping and short production runs, along with creating large, simple shaped and bulky rubber mouldings.
Injection Moulding
For applications where the highest level of precision and accuracy is needed, and intricate parts must be manufactured, injection moulding is often recommended. In this process, similarly to compression moulding, raw rubber compound is heated so that it takes a liquid form and effectively fills the mould cavity, however, rather than being pre-loaded into the mould as raw rubber, the molten rubber is injected into the mould through a nozzle.
Injection moulding ensures a continuous flow of rubber material into the mould cavity, ensuring that it packs tightly against all surfaces to achieve the desired shape, no matter how complicated the design is. Once the mould is filled, the rubber is then allowed to cool and set into the intended moulded shape.
This process is well suited to producing large volumes of simple or intricate, and small or large parts, with a high degree of precision. In addition to quality results, and a lower likelihood of waste as a result of quality inspection failure, a key benefit of injection moulding is that only the required amount of raw material is injected into the mould, so there is very little waste material associated.
Choosing Rubber Mouldings
Ultimately, the choice of moulding process depends on a range of factors, including the design of the moulded part, volume required and the time available. For guidance in choosing the right materials for rubber moulding, along with the ideal manufacturing process for your needs, you can visit cbfrost-rubber.com.