From Prototype to Production with Vacuum Casting

Bringing a new product from an initial concept to a production-ready design often requires more than simply creating a prototype. For many products, there is a stage where designers and engineers need realistic, functional components in small quantities before committing to the high cost and lead time of injection mould tooling.

Cambridge Design Technology (CDT) uses vacuum casting as part of its approach to rapid tooling and low-volume manufacturing, helping clients move quickly and cost-effectively from CAD and prototype development to high-quality physical components.

The process is particularly valuable for products such as protective cases, bespoke enclosures and specialist equipment, as well as for replicating injection-moulded components before production tooling is commissioned.

The DustCanary units shown demonstrate how vacuum casting can produce professional-quality components in small batches, with the appearance, finish and material properties much closer to a final production product than many conventional 3D printing methods.

Bridging the Gap Between Prototype and Production

3D printing is an invaluable tool during product development, particularly when designs need to be tested and refined quickly. However, as a product moves closer to production, there can be limitations in terms of surface finish, material properties, appearance and the economics of producing multiple identical parts.

Vacuum casting provides an effective bridge between prototype and production.

Rather than investing immediately in expensive injection mould tooling, a master pattern can be produced from CAD using processes such as 3D printing or CNC machining. A flexible silicone mould is then created around the master, allowing multiple polyurethane components to be cast from the resulting tool.

This makes it possible to produce a small batch of realistic, functional parts before committing to production tooling — reducing development risk and allowing products to be evaluated in real-world conditions.

Creating a Silicone Tool Directly from CAD

The vacuum casting process begins with a master pattern representing the required component. This can be produced using 3D printing or CNC machining, depending on the required accuracy, surface finish and geometry.

The master is positioned within a moulding box, and liquid silicone rubber is poured around it. Once the silicone has cured, the mould is removed from the box and carefully split to extract the master.

The two halves of the silicone mould are then accurately reassembled and clamped together, creating a cavity that precisely replicates the original master.

Liquid polyurethane resin is injected into this cavity and placed under vacuum during curing to help remove air bubbles and ensure the finished component accurately reproduces the mould detail.

Once cured, the silicone mould is opened and the finished component removed.

Because the silicone is flexible, it can reproduce detailed features, complex geometries and certain undercuts that can be challenging to achieve through other manufacturing methods.

A Production-Like Finish Without Production Tooling

One of the major advantages of vacuum casting is the quality of the finished component.

Where many 3D-printed parts retain visible layer lines, vacuum-cast components can achieve a smooth, injection-moulded-like surface finish. The master tool can also be prepared to create different finishes, from high-gloss surfaces through to satin, matte or textured effects.

The polyurethane resin can be supplied in a range of colours, meaning components can often be produced in their required colour without the need for additional painting.

For customer-facing prototypes, demonstration units and pre-production samples, this can make a significant difference. Instead of presenting a prototype that visibly looks like a prototype, manufacturers can evaluate and demonstrate a component that much more closely represents the intended production product.

More Than Just an Improved Appearance

The benefits of vacuum casting extend beyond aesthetics.

Polyurethane resins are available with a range of material characteristics and can be selected to replicate properties associated with production materials such as ABS, polypropylene and rubber-like TPEs. Transparent resins can also be used where clear components are required.

Compared with many SLA and SLS 3D-printed components, vacuum-cast polyurethane parts can offer improved strength and more consistent mechanical properties, without the layer-based weaknesses associated with additive manufacturing.

This makes vacuum casting particularly useful where prototypes need to undergo functional testing, user trials or mechanical evaluation rather than simply demonstrating the overall form of a product.

A Cost-Effective Solution for Small-Batch Production

Injection moulding remains the right solution for many higher-volume products, but the cost of producing production tooling can make it difficult to justify during the development stage.

Vacuum casting provides an economical alternative when only a relatively small number of components are required.

Once the silicone mould has been produced, multiple parts can be manufactured from the same tool. Depending on the complexity of the component, vacuum casting is typically well suited to batches of around 10 to 50 units, and in some applications can be viable for quantities approaching 100.

This can provide an important opportunity to test a product, gather customer feedback, produce marketing samples or complete pre-production validation before making a significant investment in injection mould tooling.

Designing for Repeatability and Production

Successful vacuum casting is not simply about making a mould. The design of the original component, the choice of material, the master pattern and the mould construction all influence the quality and repeatability of the finished parts.

CDT’s experience in industrial and mechanical design allows these considerations to be incorporated early in the development process.

By understanding how a component needs to function, look and ultimately be manufactured, CDT can help develop designs that work effectively through prototyping and low-volume production, while also considering the requirements of eventual manufacturing at scale.

This joined-up approach helps avoid designing a prototype that works in isolation but becomes difficult or expensive to manufacture later.

From Concept to Production

Vacuum casting is a powerful tool for companies that need to move beyond a single prototype without immediately committing to full-scale production tooling.

From the initial CAD model and master pattern through to silicone tooling and finished polyurethane components, the process can provide realistic, repeatable parts for testing, demonstration and low-volume manufacture.

The approach used for products such as the DustCanary demonstrates the value of combining industrial design, rapid tooling and manufacturing expertise to create components that are not only representative of the final product, but suitable for practical evaluation and use.

For businesses developing new products, this can mean faster development cycles, lower upfront tooling costs and greater confidence before moving into full production.

Partner with CDT

Whether you are developing a new product from scratch, refining an existing design or need a small production run before investing in injection mould tooling, Cambridge Design Technology can support the journey from concept through to manufacture.

Explore CDT’s Industrial Design and Development and Mechanical Design capabilities to see how its multidisciplinary team can help turn your product ideas into manufacturable, production-ready solutions.