Rubber manufacture as per client specification
Mapsa has been providing moulded and extruded tailor-made solutions for more than 50 years for electronics, transportation, packaging, agriculture, chemistry, construction and many other fields. Our experience in moulding and extrusion helps us to meet our clients’ most demanding requirements. Whether small or large series, simple or complex pieces, our team can help to find a solution that meets your needs. Our facilities are located in Catalonia, which allows us to offer versatility in supplying solutions that are profitable and of superior quality. From prototypes to small or large productions, Mapsa offers a unique solution for all of your rubber needs.
Mixtures (video available)
Mapsa produces mixtures with a great variety of materials, rigidity and colours to adapt to each client’s specific applications. When necessary, we can develop a composite meeting the client’s specific application.
Moulding (video available)
Mapsa’s capabilities in moulding include compression, transfer and injection. Each one of these methods has their advantages and disadvantages as opposed to the others. As follows, you will find a brief description of each one of these methods.
Compression moulding is the most extended moulding method. Its origins hearken back to approximately 1820. It is carried out by placing a non-vulcanised piece of rubber, with a pre-determined weight and size, in the cavities of an open mould. The mould is manually closed, insofar as is possible, and is placed in a hydraulic mould press. The press’ pressure makes the uncured rubber take on the shape of each mould cavity. The heat from the press plates causes a chemical reaction, known as reticulation, which vulcanises the rubber.
Our compression pressing capabilities range from 15 cm x 15 cm, the smallest, to 60 cm x 80 cm, the largest, with several press sizes in between
Advantages of compression moulding
- Economic moulds
- Less waste in mixture
- Good option for large pieces
- Good system for small series
- Good for highly rigid pieces
Disadvantages of compression moulding
- The loading and process times are longer
- The pieces need a greater finish
- The partition lines in the pieces are larger, which may create possible quality/tolerance problems
Transfer moulding is an extension of compression moulding, but with systems similar to injection moulding. It is used for applications needing greater production amounts than normal for compression moulding. The main difference between compression and transfer is that the uncured rubber is placed in a tray incorporated into the mould, and using the hydraulic press closure, the uncured rubber is forced to pass through small orifices (troughs) in the cavity.
Our moulding press capabilities for transfer moulding are the same as for the compression line. Please see compression moulding to find out information about the press’ capabilities.
Advantages of transfer moulding
- The production cycle is shorter than the compression method
- The preparation of the compound and the mould loading time is reduced, as the mould’s cavities need not be individually loaded with non-vulcanised rubber
- Product finish time is reduced. Since the mould closes before putting the uncured rubber inside, the partition line is thinner.
- Transfer moulds can work in conventional compression moulding presses without needing special equipment.
Disadvantages of transfer moulding
- The cost for the mould is greater than a compression mould
- More wasted material due to the excess remaining in the tray and the channels.
Injection moulding is carried out with a moulding press specifically designed to this end. The very press itself closes and blocks the mould. The uncured rubber is pre-heated in an injection chamber before being injected into the mould, which “plastifies” and allows easier flow through the injection system and the cavities. This, along with the closure and the injection force provided by the press, allows for high curing temperatures, shortening the production cycle. Our injection presses have capacities ranging from 45 cm x 45 cm to 60 cm x 80 cm, with tonnage (closure force) of 100 to 800 tons. The closing force of an injection press is what keeps the mould properly closed during injection and the curing time.
Advantages of injection moulding
- Shorter production cycle than the other two methods, due to greater holding/injection pressure and curing temperature
- The greater productivity than with the other methods translates to lower unitary price
- The high closing pressure makes the pieces have smaller partition lines in comparison with other methods
Disadvantages of injection moulding
- Requires large productions to be efficient.
- Mould cost considerably greater than other methods
- Not all compounds or levels of hardness are adequate for this process
Extrusion (video available)
Our extrusion lines are able to produce profiles as per client specifications, pipes, washers and cut seals, as well as vulcanised joint seals, seals with injected corners and moulded seals in a great variety of shapes and sizes. The extruded profiles may be supplied in bobbins or cut length. The profiles may be manufactured to have orifices, slots or special cut outs adapted to a specific application. The sizes of the extruded profiles we produce vary according to the configuration of the extruded profile. We can manufacture pipes and cords from 1.5 mm to 40 mm in diameter. On the other hand, the profiles may be up to 40 mm x 150 mm. The wall thickness of the extruded profiles, like pipes, may be 1.2 mm, but in any case, it will depend on the shape of the transversal section since the pipe and thin wall profiles tend to collapse during the curing process. To overcome this, we manufacture special tools that keep the shape of the profile during vulcanisation. In these cases, there is an additional cost since they are a bit laborious. However, the final result is most definitely worth it for applications when normal extrusion and the curing process is not enough.