R_Bibb_Medical_Modelling_The_Application_of_Adv.pdf

84 Medical modelling
running. However, once correctly set up, the machines are relatively
reliable.
The materials, although reasonably accurate and tough, remain porous.
Although the materials themselves pose no inherent medical problems, the
porosity makes them particularly diffi cult to clean and sterilise effectively.
Like most RP models, LS models are opaque, which may hide internal
details. A typical LS medical model is shown in Fig. 5.18.
Also available is a sand-based material that can be used to make sand
moulds and cores for casting metals, allowing components planned for
manufacture by sand casting to be prototyped relatively quickly in the
production material by the production process. The direct forming of sand
moulds and cores could improve prototyping times for complex sand
castings.
Some LS machines are capable of producing metal objects using special
alloy powders or metal-polymer binder mixes. These materials are not
highly functional but are intended to produce mould inserts for injection
moulding in small volumes.
5.18 SLS ® model of the mandible.