Industrial Products: the vacuum casting advantage for low volumes

Vacuum casting is a manufacturing process commonly used for producing industrial products, particularly in the field of rapid prototyping and small-scale production.

Involving the use of silicone moulds and polyurethane resins, vacuum casting offers several advantages for industrial product manufacturing, including the ability to produce complex and highly detailed parts; a wide range of material options; cost-effectiveness for low-volume production; and relatively short lead times compared to traditional manufacturing methods.

The Process:

It all starts with the creation of a master pattern. This is normally made through via 3D printing (Paragon offers SLA for very fine detailing, and SLS for a more cost-effective process); or through the subtractive process of CNC machining.

A silicone mould is then created from the master pattern. The master pattern is placed in a mould box, and liquid silicone rubber is poured over it. The silicone is allowed to cure, forming a flexible and precise mould around the master pattern.

Once the silicone mould has fully cured, it is carefully cut to create multiple parts. Simple parts may only require a two-part mould; more complex parts can require several cavities.

Depending upon the desired properties of the final product – whether it be transparency, flexibility or heat resistance, (generally) a thermoplastic, rubber or other polyurethane resin is selected. This is mixed with any required additives, such as pigments or reinforcing agents, to achieve the desired characteristics.

The silicone mould is then securely clamped (sometimes in a wooden box to hold its shape), and the prepared polyurethane resin is poured into the mould. This is then placed in a vacuum casting machine chamber, which is sealed. The ‘vacuum’ part comes when all the air is sucked from the chamber – removing any that has been trapped and promoting thorough resin penetration.

The mould is then transferred to a curing chamber (a special purpose oven, if you like). The resin is allowed to cure and solidify, typically at an elevated temperature for a specific period. After the part removal, the mould can be reused some 25 times before needing to be re-cast. Silicone moulds are relatively ‘cheap’, making the process far more cost-efficient, and considerably faster, than injection moulding. It’s absolutely ideal for small-scale production or rapid prototyping.

Vacuum casting can be carried out with a variety of materials, from hard, transparent thermoplastics to soft polyurethane rubbers.

Industrial Product Applications

Vacuum casting is ideal for the creation of parts for industrial products, such as in (but not limited to):

  • Filtration Systems: sealing bellows, water separator spinners, seals, end caps, perforated flasks, custom spigots, connectors
  • Safety Equipment: frame bumpers, sensor mounts, face masks and visors, audio equipment and ear defender components, respirator components, wearables, hose retainers, security equipment housing, packaging, monitoring equipment and handheld devices
  • Machinery and Appliances Manufacture: electronics housing, agricultural equipment components, knobs and keypads, remote control housing
  • Lighting: lenses, signage, handheld and mounted all weather cases, emergency lighting systems
  • Robotics: housing, rotors, connectors, joints


Paragon offers some 12 vacuum casting resins, from transparent to flame retardant to soft rubbers. Their profiles and short Technical Data Sheets (TDS) are available through our website. If you have a specific material in mind or feel that those shown on the website don’t quite match your desired properties, please do talk to us. The Paragon ethos is one of collaboration and we’ll work with you through design, development, and materials research until you have a perfect match.

To discuss your vacuum casting project, you can call us on 01325 333 141 or email

Alternatively, send us your CAD and requirements for a quote by clicking the orange button below.