Rubber moulding is a process of transforming uncured rubber or an elastomer into a usable product by transferring, compressing, or injecting raw rubber material into a metal mould cavity.

What is Rubber Moulding?

Rubber moulding is a process of transforming uncured rubber or an elastomer into a usable product by transferring, compressing, or injecting raw rubber material into a mould cavity. The applied heat and pressure create a chemical reaction, called curing or vulcanization, which causes the polymer chains in the material to crosslink and form a rigid structure in the shape of the cavity.

What are the different types of Rubber Moulding?

The most commonly used methods for rubber moulding are:

  • Rubber injection moulding
  • Rubber Compression moulding
  • Rubber Transfer moulding 

At Clifton Rubber we have a diverse mix of hydraulic presses. This means we can make components using any of the three primary moulding processes – compression, transfer and injection.

This capacity mix gives us the flexibility required to make a broad range of rubber products.  These can be small parts up to very large parts and one-off prototypes through to high volume continuous production runs.

What is Compression Moulding?

Compression moulding is the most widely used moulding technique due to its simplicity compared to transfer and injection moulding. 

The process involves placing a preformed blank of uncured rubber compound in the centre of a mould cavity. The mould is then closed before heat and pressure applied to the compound to induce the vulcanisation reaction. 

During this vulcanisation process the compound will take the form of the cavity resulting in a product which meets the specific shape required. Once the material has fully vulcanised the mould is opened and the product removed.

Compression moulding is generally suitable for low to medium production volumes where the shape of the product is relatively simple. It is also the most suitable method when the size of the product is large and requires a long cure time.


  • Simpler process 
  • Less wastage
  • Cost effective 
  • Lower cost of tooling
  • Ideal for small production runs
  • Good for larger components


  • Longer lead times
  • Less consistency of finish
  • Not suitable for complex designs

What is Transfer Moulding?

Transfer moulding uses similar equipment to compression moulding.  The major difference between the two processes is that the mould tool is more complex in design. The transfer moulding process requires a pre-formed blank of raw rubber compound to be inserted into a “pot” in the mould, when the mould is closed the piston will locate in the pot and force the rubber compound from through the transfer holes and into the closed cavity. Once in the cavity the compound will be heated to its specified cure temperature whilst taking the form of the cavity. Once vulcanised the mould is opened and the product removed.

Transfer moulding is used generally for low to medium volume production runs but is more suitable than compression moulding when moulding complex shapes. Also, the process is more suitable when over-moulding or bonding to other materials such as metals or fabrics.

Clifton Rubber’s vast experience of transfer moulding products means that when it comes to manufacturing a product for our customers, we can guarantee a high quality. Typically, we can transfer mould rubber to metal or rubber to fabric bonded items such as engine mounts, tipper blocks, pump diaphragms etc.


  • Increased accuracy
  • Shorter lead times
  • Lower tooling cost
  • Larger production rates
  • Lower maintenance costs


  • More material wastage
  • Labour intensive
  • More complex moulds

What is Injection Moulding?

The significant difference when comparing rubber injection moulding to transfer and compression moulding is its ability to be fully automated therefore reducing the requirement for skilled operatives to be present at all times in the process. The injection moulding process requires uncured rubber compound strips to be directly fed into the injection unit. 

The injection unit heats and plasticises the material which is then injected directly into the closed mould tool. Using gates and runners the material flows into the cavity (or multiple cavities) and once the material has fully vulcanised the mould opens and the parts are ejected.

Injection moulding is used generally for high volume production runs of both simple and complex shapes. The mould tools required are generally more complex in design than transfer or compression moulds, but the automation of the process and elimination of preformed blanks means that typically unit prices are lower.


  • Allows for large volumes of uniform, complex parts
  • Compatible with wide range of materials and colours
  • Fast turn around times
  • Repeatable and reliable process


  • Higher start up cost
  • Initial lead times are longer
  • Expensive design changes