Properties such as durability, flexibility, and resistance to ageing make rubber an essential material in almost all household and industrial appliances and products. A large number of products, tools, and appliances that we use today are made from rubber or contain rubber components. However, to make the raw rubber suitable for use in commercial products it needs to undergo processing. A number of products and components are manufactured through the process of rubber moulding. If you are wondering ‘what is rubber moulding’, you are probably not the only one. Rubber moulding is a process of shaping the rubber under heat and pressure to ‘cure’ or ‘vulcanize’ it. In the first stage of processing, the raw rubber is mixed with additives and curing agents in the mixing stage giving rise to uncured rubber. It is difficult to model uncured rubber into a product due to its inability to resume its original shape, despite pressure. Moulding is the process by which an elastomer is cured (technically speaking forming ‘crosslinks’) and shaped into a product.
This process can be conducted using different methods, namely, rubber injection moulding, transfer moulding, and rubber compression moulding. The latter is a simple process used for producing components ranging from a few prototypes to large commercial quantities cost effectively
Rubber Compression Moulding Process
In the compression moulding process, a piece of uncured rubber is modelled into a pre-form which will roughly resemble the desired final product. A two (or multi)-part metal mould of the desired shape is acquired. Both the parts of the mould are heated to a specified temperature. The piece of uncured rubber is placed in the cavity of the heated mould, which is then sealed. Pressure is applied by using a high-power press so that the uncured rubber can blend into the shape of the mould.
Throughout the process, heat is continuously conducted through the two parts of the mould in order to obtain the exact desired pattern for the rubber. The process is carried on for a specific amount of time, after which the mould is opened to obtain the cured rubber product.
Advantages of Compression Moulding
- Simplicity
The simplicity of this process is a major advantage as it is quite easy to conduct. It involves a largely uncomplicated process and, therefore, does not require complex equipment or tools
- Cost-Effective
As the process does not require any specific sophisticated machinery, it tends to be quite affordable therefore considerably lowering the cost of production.
- Less Waste
Compared to other methods, like injection or transfer moulding, the amount of waste and scrap generated during compression is minimal.
- Widely Applicable
The process is applicable for most elastomers and, therefore, can be used for manufacturing different kinds of rubber products.
Compression moulding can be used to produce a variety of rubber products for both industrial and home use, from electrical parts and gaskets to buttons and knobs.
Learn more about our Custom Rubber Moulding and Extrusions.