3D Printing and Additive Manufacturing are terms most often associated with being the latest processes to burst on to the scene of the manufacturing industry. However, at PI Castings we have been utilising this technology for over 30 years!

We adopted this technology when the first stereolithography machine arrived in Europe. We are one of only a few independent investment casting manufacturers in the UK that have their own 3D printing equipment. Why was it so important that we invested in this technology? The answer is simple… We wanted to be able to meet the demands of our clients who were requesting Rapid Prototype castings. Client satisfaction is our primary concern, and this equipment allows us to have greater control over the production of our rapid prototype castings. Our years of experience have allowed us to refine our manufacturing techniques and produce these castings in a time scale and at a cost that pleases our clients.

Aluminium Rapid Prototype Castings - Rapid Prototype Image 1


So, how do we do it?

Our clients often ask how we produce our rapid prototype castings, when we explain that we use the same casting techniques as we would for a production casting, the question “why are the lead times for rapid prototype castings shorter than those for production castings?” usually follows…

Production times can be reduced by up to 5 weeks due to the fact that are rapid prototype castings do not require tooling in order to be produced. This is where our 3D printing equipment becomes invaluable. We are able to produce the patterns that are required to produce castings using our wax thermojet printer, as opposed to using Aluminium tooling to create the patterns as we would for a production run. (For more information about how we produce production castings, be sure to take a look at our investment casting process page). This dramatically reduces production time and cost.


When manufacturing prototype castings we follow this process:

Pattern Creation

A wax pattern that is an exact replica of the desired casting is produced using our wax thermojet printer. In some instances, this pattern is created using another additive manufacturing technique; such as Stereolithography, Quickcast, Selective Laser Sintering (SLS).

Rapid Prototype Castings Pattern Creation Process
Rapid Prototype Castings Pattern Assembly Process


After the patterns have been cleaned, feeders are attached and the patterns are assembled on to a grid.


These assemblies are then dipped in a high grade ceramic slurry. Whilst still wet, the assemblies are then coated in larger particles of ceramic. This step is repeated until a ceramic shell has been built up around the rapid prototype casting patterns.

Rapid Prototype Castings Shelling Process
Rapid Prototype Castings Dewaxing Process


After the shell has been dried thoroughly, the wax patterns are melted out in a steam autoclave. At this stage patterns that have not been created in wax are ‘burnt out’ of the shells.


Whilst the ceramic shells are still hot, the required metal is poured in to these ‘moulds’ in order to form the rapid prototype castings.

Rapid Protype Castings Pouring Process
Rapid Prototype Castings Shell Removal Process

Shell Removal

Once the molten metal has cooled and set, the ceramic shells are removed from the castings.

The Last Steps

Once the rapid prototype castings have been revealed, they can be fettled, blasted and heat treated in accordance with our client’s requirements. Material testing, X-Ray, Dye Penetrant testing, mechanical testing and machining can then be carried out as required.

Rapid Prototype Castings Last Steps of the Process


It is the pattern creation stage, and the pattern creation stage only, that differs from the process that we use to manufacture our production investment castings. This allows us to manufacture rapid prototype castings that have the same properties as castings that would be produced in a production run.

For more information on how we can manufacture rapid prototype castings for you, contact our team now. If you would like more information on what we require to produce rapid prototype castings, take a look at our rapid prototype design page.


Get in touch

If you have any questions about our Investment Casting services, Machining services, Rapid Prototyping services or Low Cost Sourcing services, please make contact with one of our capable engineers and they will provide you with more information