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4 April 2014

Replicas for the new Staffordshire Hoard Gallery – Phase Two

In collaboration with Birmingham Museums Trust the Jewellery Industry Innovation Centre (JIIC) have continued their work developing, adapting and refining the various digital technologies available to them to produce a batch of initial, trial, 3D prints of K270 for the museum to evaluate.

The next stage required JIIC team member Mark Watkins to add ‘support structures’ to the CAD file described in the previous blog: 3D scanning to create Staffordshire Hoard replicas. These support structures are an integral part of the particular 3D printing process being tested out for suitability here.

Image 1: CAD file of K270 with support structures added.

Next the CAD file was processed into the 3D printer which was left to run for the six hours the K270 print required. This printer works by using a photo-polymerisation process whereby exposing the liquid resin to precisely positioned ‘masks’ of light of varying wavelengths causes the light to instantly solidify the resin and the object is built up layer by layer. (More information on this process can be found here http://envisiontec.com/technology-overview/).

Image 2: K270 on the printer and rising out of the resin bath.

The support structures were then removed and carefully trimmed back smooth by JIIC team member Samantha Chilton leaving us with the finely detailed resin replica of K270 shown below.

Image 3: K270 in resin.

This resin ‘master’ pattern was then used to create a rubber mould, using a process known as vulcanisation, into which wax will be injected to create a sacrificial casting pattern used in the lost wax investment casting process.

Image 4: The K270 resin master pattern ensconced in its vulcanised rubber mould.

The resin master pattern is then carefully and precisely cut out from the mould using a very sharp scalpel blade (image 5).

Image 5: The resin master is cut from the mould.

Eventually the mould is completely split into two halves and the master resin removed (image 6).

Image 6: The two halves of the mould and the master.

The two halves are then placed back together to create the mould void into which liquid wax is injected under pressure to create the sacrificial wax pattern for the casting process. The wax is injected into the mould (image 7), creating sacrificial waxes from the mould (image 8).

Image 7: Wax is injected into the mould.

Image 8: Waxes from the mould.

In a later blog we will look in more detail at how these waxes will be used in lost wax investment casting process.

 

Frank Cooper

JIIC Manager