Prototypes Parts of vacuum casting

What is vacuum casting?

Vacuum casting can be used to make small amounts of high-quality. Intricate parts in polyurethane quickly, with a lot of flexibility. A reasonable price. Most of the time, these pieces appear to have been hand-molded from technical plastics or thermoplastic elastomers (TPE). Vacuum casting is also a great way to make overmolding.

Silicone rubber moulds are used to make polyurethane (PU). A vacuum pulls out any air that is trapped inside the mould. After the item has hardened, it is pulled out of the mould and finished in a separate process.

Polyurethane comes in a wide range of grades. It can be used to make a wide range of things, from soft rubbers to hard plastics.

What is the vacuum casting process?

The first step is to create a master pattern, which is commonly done with SLA 3D printing. Then hand-finished to a high level of quality. The master pattern, in addition to the casting gate and risers, may be 3D printed. Include a casting gate and risers that are 3D printed independently and then attached.

With the help of a box made by someone else. The master pattern with the casting gate and risers is put inside. Liquid silicone rubber is then poured around it to make the mould. This is done in a vacuum chamber to get rid of the air in the silicone. Make sure there are no bubbles in the silicone that would make the surface of the mould look bad. After that, the silicone is cured by heating the mould. This is how the silicone is made.

After curing, the mould is carefully cut, the master pattern is removed. The mould is thoroughly inspected before being used again.

A funnel for pouring liquid polyurethane into the mould was added. The mould is then returned to the vacuum chamber.This is where the polyurethane will be injected. Thus all polyurethane characteristics are moulded and the surface quality is faultless. You can do this in a vacuum. It takes a while for the polyurethane to harden in the mould.The polyurethane is hardened by heating the mould..

It is necessary to open the mould once the polyurethane has hardened and cooled before removing the portion as well as cutting off the gate and risers. The item is next inspected and finished.Some parts may require placement on a curing fixture for an extended period of time (up to 7 days). In order to keep their shape or to meet tighter tolerance requirements.

When is vacuum casting used?

Vacuum casting is a process that can be used for both prototypes and finished items. For idea models, visual models, pre-production prototyping, functional test prototyping, thermal and air flow testing models, and assembly line trials. it is a versatile tool.

Adding elastomeric sealing characteristics to parts produced by other prototyping processes, as well as overmolding metal components, are two applications for vacuum casting. It is particularly well suited for functioning prototypes.

Polyurethane is sufficiently durable for end-use parts such as elastomeric seals, overmoulded ergonomic grips, and complex geometries, for example.

Vacuum casting is utilised in a wide range of industries, including medical, life science, automotive, aerospace, and general manufacturing, amongst others.

Casting capabilities in a vacuum

Electronic differential pressure control systems, as well as automatic silicone degassing, allow our vacuum casting chambers and ovens to produce parts of exceptional quality and consistent reproducibility.

There is a maximum weight limit of 1400g, and the maximum mould size is 450,470,400 millimetres.

Molds can be reused up to 25 times, depending on the geometry of the object and the polyurethane grade used.

For further details, please see our vacuum casting data sheet.

Characteristics of vacuum cast parts:

Vacuum casting produces high-quality replicas of the master with features such as snap fittings. Because the master patterns have a good surface finish, this one has a good one too.

The physical qualities of the material are directly related to the polyurethane grade that was employed. Some grades of polyurethane can even be fire retardant, depending on the grade. Polyurethane is non-porous and doesn’t get water or heat.

Vacuum cast pieces can be finished in a variety of ways:

Functional parts such as elastomeric seals are usually only cleaned. Using pigments in the basic material, parts for visual models or practical prototypes are likely to be self-colored.

We can construct vacuum cast parts utilising prototype parts or off-the-shelf components. When other parts need to be screwed together, we usually use cast-in threaded inserts.

Blackout/EMI/RFI coatings can be applied to internal surfaces, and parts can be vacuum metallised.

Materials that can be used in vacuum casting:

We have polyurethane resins that meet most of our customers’ needs. Whether they want rubber-like parts with Shore. A hardnesses from 25 to 95, or rigid parts that look like injection-molded engineering plastics.

We cast polyurethane in a range of colours and tints including water clear.