R_Bibb_Medical_Modelling_The_Application_of_Adv.pdf

90 Medical modelling
5.22 InVision TM model of the mandible.
Unlike the other machines, that use large numbers of print heads to
accelerate building speed, the Solidscape machine utilises a single print
head. This makes these machines highly accurate, with very thin build
layers, and hence models show an excellent surface fi nish. However, this
makes them extremely slow and limited to a very small build envelope.
However, they are proving popular with the jewellery trade due to their
small size and suitable casting materials.
In medical terms, the wax materials are weak and diffi cult to sterilise due
to their low melting points. The materials are opaque, which may hide
internal detail, but the wax materials lend themselves well to casting processes.
However, the Solidscape machine is capable of producing very
accurate models of extremely small objects. The relative accuracy of the
Objet process and the transparency of the materials make them ideal for
medical modelling and comparable in most respects to SL models. In addition,
an Objet build material has recently been tested to an internationally
recognised standard for plastics (USP 23 Class 6) and may, therefore, be
sterilised and used in theatre. Recently softer, rubber-like, materials have