​Quality and safety in the manufacturing of completed goods is in the name of competitiveness and efficiency of the production process. With these creative and avant-garde proposals, PMI SRL is able to create technical rubber goods and methods for rubber casting. In this post, we want to inform you about the numerous ways that can be used in rubber casting and the different approaches that may be employed according to requirements in different processes.

What are the working process of rubber casting

The earliest technique of casting rubber, compression casting, started to take place about the ‘900; 40 years of effective expertise in injection casting have begun around the road to create a number of items; casting injection compression, a mixture of the two rubber processing methods mentioned above, but incorporates the processing of the material limits; Finally, but not least, the transfer technique is used for rubber casting.

Let us examine more closely at the different rubber processing techniques.

Casting of compressed rubber.

Let’s begin with the earliest rubber vulcanization process. In the 1930s and 1940s, the first press in Italy was launched by Terenzio Sa which could be compressed by about 25-30 tons. In the early 1950s, the firm developed a new raw material moulding method and product line that allowed greater pressures of up to 3,000 tons. Today, compression moulding is primarily used for the preparation of small and medium batches and is even more suited for sampling since it takes more time to vulcanize rubber than the injection moulding and needs more human interventions.

Injection rubber casting.

The most commonly utilized technique of mass manufacturing is rubber injection casting. This technique may enhance the quality and accuracy of the product as a whole and can simultaneously mass-produce products. Unlike compression casting, where the raw material is inserted at “room temperature”, heated and vulcanized in the mold, during the injection casting process, the rubber is injected at a higher temperature and pressure through the injection chamber in the closed mold. After the rubber has been vulcanized, the mold is opened and the connected product may be removed automatically. 98% of the material is injected into a closed mold (usually), and then 100% of the parts are completed in the “maintenance” phase or also known as the “compaction” phase, during which the material is kept under pressure until, in fact, it does not solidify Into the shape of the mold.

Compression injection casting.

The rubber casting process, as stated above, involves compression and injection. It is mainly used for small components that do not need to withstand high mechanical pressure and maintain high precision and quality of components (especially used in the process of manufacturing electronic, optical, and medical components). In this production process, the material is directly injected into a semi-closed mold at a high temperature, and then compressed to maintain the desired shape until it solidifies. This process is conducive to 100% filling of the mold after curing, which has already started at the first injection, to avoid the need to repeat the operation when the product shrinks after curing and leaves a blank space in the mold. Another advantage of the injection linked to compression is that the material is spread uniformly throughout the mold.

Methods of rubber casting and transfer.

This rubber processing method is used for rubber metal products with higher mold costs. The raw material can be inserted into a specific cavity in the mold at high temperature or solid temperature, and then a piston or press pushes the material into the cavity of the preheated mold.

The heated mold allows the casting material to fill all spaces, avoiding partial filling. Once the material fills the mold, vulcanization will be faster than the classic compression method.