The Difference Between HCR Silicone Compression and Extrusion Molding

Generally, HCR silicone rubber molding methods include compression compression and extrusion molding. Each molding process has its own advantages and disadvantages. The comparison of HCR silicone rubber compression and extrusion molding processes is listed below.

HCR silicone rubber

1. Molding Machine

The compression molding process is molded by vacuum vulcanizing machine, while the extrusion molding process is extruded by extrusion machine.

2. Vulcanizing Agent

The compression molding process is generally through the addition of odorless vulcanizing agent or double two five vulcanizing agent, the cut strips or sheets of HCR silicone rubber raw materials into the machine after high-temperature vulcanization molding.  Extrusion molding process is through the addition of double two four vulcanizing agent or platinum vulcanizing agent, and then directly the whole HCR silicone rubber raw materials into the container after extrusion vulcanization molding. It should be noted here that if the silicone rubber for compression molding is to reach the food-grade it must use odorless vulcanizing agent, and the extruded silicone rubber must use platinum vulcanizing agent to reach the food grade.

3. Molding Speed

The compression molding process time takes 60-180 seconds, and the extrusion molding process time only takes a few seconds.

4. Application

The compression molding process is applicable to the production of silicone products with certain size and shape and limited length. For example, silicone cell phone cases, silicone seals, baby pacifiers, etc. are all produced by the compression molding process.

Extrusion molding process is suitable for the production of silicone products in the form of tubes or strips without length limitation, such as silicone water pipes, silicone seals, etc. are produced by the extrusion molding process.

5. Storage Time

Silicone raw materials for compression molding can be stored for about one month after adding vulcanizing agent, while silicone raw materials for extrusion can only be stored for about 3 days after adding vulcanizing agent. If no vulcanizing agent is added, it can be stored for one year.

Comparison of advantages and disadvantages of molding and extrusion processes
  Compression Molding Extrusion Molding

1. It is not limited by shape, and can be customized according to requirements.

2. High precision, neat and beautiful product shape.

3. The colors are bright and can be adjusted at will.

1. Not limited by length, can be unlimited length.

2. Short production cycle and high capacity.

3. There are almost few waste products.

4. Low mold production cost and high speed.


1. Most of the machines can only produce specifications of 500mm in length and 500mm in width.

2. There will be a lot of burrs and scraps in the production process.

3. The tooling cost is relatively high, and the development cycle varies from 7 to 25 working days.

1. It can only be made into tubes or strips, and the shape can only be simple.

2. The precision is poor, and the error of product size over 10mm is relatively obvious.

Tagged: hcr silicone

Related FAQs