AMAP (The Institute for Automotive and Manufacturing Advanced Practice) recently turned its advanced engineering equipment and skills to help Northumberland Archives create a replica of its ‘Great Seal of the Realm’; a rare artefact that can’t be displayed publicly because of its delicate nature.
When Northumberland Archives decided they wanted an exact replica of the Great Seal of Queen Elizabeth II and its attached parchment to go on public display, they asked Durham County Record Office for expert conservation assistance.
Durham’s Archive Conservator concluded that the seal was potentially made of ‘cella mold’, an early plastic made of cellulose acetate. This plastic can become unstable in contact with certain chemicals which can trigger its auto degradation and unstoppable deterioration.
As traditional casting methods involve the application of various chemicals onto and near a seal, another method of replication had to be found. That’s when Durham County Record Office turned to the advanced manufacturing experts at AMAP, which is part of the University of Sunderland, after hearing of their reverse engineering and rapid prototyping capabilities.
The Great Seal of the Realm is the chief seal of the Crown, used to show the monarch’s approval of important State documents, in this case the document relates to the district of Castle Morpeth being given the status of a borough in 1974.
AMAP managing director Roger O’Brien said: “We’re really proud of the outcome of this project, which used engineering techniques to solve a non-engineering challenge.
“The project appears simple, but in reality shows the power of modern advanced manufacturing processes when applied in unexpected ways. It was a great experience for the AMAP team; we were able to apply our state-of-the-art 3D scanning, reverse engineering and 3D rapid prototyping technology to replicate these historical artefacts for Durham County Record Office.
“The historic wax royal seal was scanned using the latest Faro v6 Scan Arm, then reverse engineered through Geomagic and Solidworks to create a finely detailed 3D model, which was then printed on a high precision 3D printer. Finally the conservator spray-painted the replica to colour match the original and attached braided ribbon.”
County Archivist, Liz Bregazzi, commented: “We got in touch with AMAP at the University of Sunderland, who kindly agreed to work with us to produce a replica seal. The project has been an interesting and exciting one for all involved. Now the final task of colouring red the printed seal and producing a replica braid is complete I’m delighted to be able to receive it and for this very accurate replica – of what is an important artefact – to be accessible to the public to see and even handle.”
Roger concluded: “We’re very pleased with the impressive results and it’s great to see the replica on display to the public. We were able to produce a highly precise and robust replica that can be displayed and handled, as well as being unaffected by pollution, so can be enjoyed by people for many years to come.”