Design Realization/Detailed Design - Medical Device Design: Innovation from Concept to Market - page 180

PC communicates with RP
machine using print protocols
over wire or over Internet

RP produces 3D solid in “hours” CAD produces 3D model (usually STL)

Figure 8.16
A typical rapid prototyping system.

8.6.9 Rapid Prototyping (RP)
Once again, the rapid growth of the PC has made this technology viable. It is just as easy,
nowadays, to print a solid object as it is to print text on a page. Even the machines look similar!

The basic principle (as illustrated in Figure 8.16 ) is the same as an inkjet printer, except that
in most cases instead of printing ink you are laying down layers of ABS. After numerous
layers a 3D solid emerges that is close to your design. The more expensive the RP machine
the more accurate the model. Do not think that only plastics are used; you can RP in ceramics
and metals. I have seen RP products in stainless steel and in titanium. I have even seen results
of tests that suggest that they are as strong as solid models. I have even seen RP solids in
hydroxyapatite. Now we really are opening the doors to bespoke human engineering. Figures
8.17-8.18 illustrate some typical commercial RP machines.

8.6.10 3D Visualization
Some of you may have seen 3D movies at the cinema. This technology is heavily used in the
design environment. Many modern CAD systems enable the user to produce 3D simulations
of the object concerned, just as in the cinema and as illustrated in Figure 8.19 . While the
designer may think this nonsense, for the nondesigner and the end-user this is highly valuable
to provide early feedback. The same issues apply as to 3D cinemas; you need specialist 3D
projection systems. But the rise of 3D television has made this more attractive to design
houses. At this moment in time not all CAD software has this ability and you may need
to export items to specialist visualization software. The time will come when this form of
visualization becomes commonplace, and even the designers will probably be working in
virtual-3D as the norm.