When Jet Cooper presented us with the first element of his vision of the future of prop and modelmaking, consolidated into the promised beauty of Aurora, he gave us 16 CAD files containing 20 parts. These would be assembled into her head.
The ultimate aim of Aurora is to demonstrate the versatility of 3D printing for prop and model making, and at the same time show that some of the older, tried and tested methods can be incorporated into the assembly without compromising integrity or effect. The 20 components of her head are designed to click together with magnets, coming apart for demonstration purposes.
With an array of 3D printing and more traditional rapid technologies at our fingertips, the questions revolved around which technologies should be used for which parts? And, more significantly, which materials would be given the main roles?
Our NEO 800 SL (stereolithography) printers are deemed the most advanced of their kind. We have three, and ours print in two hardy photopolymer resins that offer the smoothest of surface finishes and allow for intricate detail.
SOMOS® EvoLVe 128 is a durable stereolithography material that producing extremely accurate parts and supports intricate detailing. DSM designed the resin for easy finishing (a time-saver) and its smooth, shiny surface with a very slight flexibility is beloved of model makers everywhere. It requires priming when painting and texturing, but the end results are nothing short of spectacular.
SOMOS® WaterShed XC 11122 offers outstanding clarity and the same level of intricate detailing as EvoLVe 128. It’s a much harder resin when cured, making it a popular choice for creating cores and master patterns for use with other, more traditional processes such as vacuum casting. WaterShed is also highly water resistant and bonds well to other materials with just your regular range of modelling glues. That’s ideal if you would like to make some post-printing additions.
Aurora is a showcase for our 3D printing capabilities. She’s designed to come apart for closer inspection, and she’s also designed to be a functional android, eventually. She wouldn’t be able to do either if she didn’t include some SLS, or selective laser sintering, components. For these parts we chose the PA 615 – GS Nylon, a 50% glass filled thermoplastic with a reputation for its strength and durability.
Last but not least, we included some vacuum casting for rubber components. We have an ability to print in silicone rubber using our DLS technology. However, we felt that vacuum casting would allow us to vary shore hardness and colour to achieve the perfect results.
Scripting the parts
For the integral skull, jaw and parts representing metal components, our model making team opted to use SLS and the PA 615 – GS. The model needed a strong structural material that would not only withstand the continual handling during assembly and breakdown, but would also give a bit of weight to the piece.
SLS, in the words of another renowned model maker and animatronics designer, Josh Lee, is a great process. He says of the resultant print, “We use SLS for end-use parts because once polished up, you cannot see the layering. It’s easy to paint and bonds well with other parts. We’ve also found the slight porosity of the SLS is actually advantageous for us; it grabs our paint system really well and the paint never cracks or flakes off.”
We ran test prints of the outer shell components marked ‘opaque’ first in SLS, but opted for SLA printing using EvoLVe 128 ultimately because the definition is infinitely superior. EvoLVe has a nice, smooth plastic feel and we wanted these components to feel like a polymer. The smooth, shiny surface would also reflect light beautifully once finished.
EvoLVe is a slightly flexible material, and printed off our NEO 800s, can be pushed to the limits when it comes to wall thickness. This meant that we could incorporate holes into the B surface of the shells at strategic points without compromising the integrity of the piece.
The transparent components were also printed in SLA, as were the cores for our vacuum cast parts. WaterShed XC 11122 is beautifully transparent when polished up; and can be tinted. The resultant print is rigid and ultra smooth, and can include intricate detailing.
Last but not least, we incorporated an element of vacuum casting. We sought to create some definition and textured material for the eye mask and the chin, and a quick cast using a grey rubber would allow for this. Rubber is tough and pretty tear-resistant. Eventually, Aurora will be mechanised and the rubber of her chin and collar bones will provide greater flexibility and smoother movement when she talks and moves.
In Episode 3 we will explore finishing and painting, featuring a supporting cast of Paragon Model Makers.