FDM Digital Solutions, a UK leader in additive manufacturing, sought out Paragon RT’s help in developing suitable tools for a replica aircraft seal application.

The seal creation required a complex tool manufacture combining soluble additive manufactured tooling with Paragon’s RIM casting ability. The specific issue was that there was a need to create a long internal cavity within the replica aircraft seal.

This complex and challenging geometry within the design warranted a joint research and development process.

The processes

FDM had already recognised that a RIM-cast process for the rubber component was the most suitable for this application. Materials designed for RIM also offered up the most favourable properties.

However, discussions with the Paragon team also established that standard RIM tooling would be unable to produce the large cavity required in the end component.

As the team at FDM had access to a range of soluble materials, the suggestion was made to produce a soluble insert in order to create an internal cavity within the moulding.

Paragon CNC machined a rigid model board compression tool. The end section of the moulding was then formed around the soluble core. The moulding was removed with an air-line and the cores were dissolved to leave a cavity in the seal as required.


Both FDM and Paragon are very excited about the potential applications of this two-stage process, which could produce some extremely complicated cast components.

“Collaborating with Paragon’s experienced engineers we were able to design a solution which enabled us to create the complex seals using soluble additive manufactured cores. The customer was very satisfied with the results and we see there being many potential uses for this application.”

Replica aircraft seal