C4 – Rapid Prototype Manufacture

Option C: CAD/CAM
Wet Rapid Prototyping.
 A technique that uses a fluid support structure that
can be washed and drained away.
Stereo Lithography.
 Stereo lithography (SLA) is a 3D printing process
that uses a vat of photosensitive resin and a vertically
moving platform.
 It uses a laser beam, directed onto the surface of the
photosensitive resin, to print the pattern of the
current model layer by hardening the photosensitive
 The platform then moves down by a layer thickness
so the next layer can be printed.
Dry rapid prototyping.
 A technique that uses break-away supports.
Laminated Object Manufacture (LOM).
 LOM machines take the sliced CAD data from the 3D
model and cut out each layer from a roll of material,
using a laser or plotter cutter.
 These sliced layers are glued together to form the
model, which is either built on a movable platform
below the machine or on pins when using card.
Solid Object Printing.
 Solid object printing, in particular wax modelling,
employs inkjet deposition technology.
 A linear array of nozzles deposits molten wax on a
platform, layer by layer, to build up the 3D model.
Fuse Deposition Modelling
 An FDM machine is basically a CNC robot that holds
a small extrusion head.
 The extrusion head moves back and forth along a
platform, building up a 3D model by feeding heated
plastic wire through the extrusion head.
Select Laser Sintering (SLS).
 SLS is a 3D printing process based on sintering.
 A CO2 laser is used to sinter a thin layer of heat-
fusible powder that gradually builds up the 3D
Compare wet and dry rapid prototype
 Wet techniques can be used for more intricate
internal construction where it would be difficult to
break away supports.
 Dry techniques use a breakaway structure, which can
be difficult to remove from detailed areas.
Benefits of being able to rapid prototype a
product instead of using other CAM techniques.
 Consider…
 Product design
 Speed
 Time
 Costs
 Accuracy
 Waste.
Limitations of rapid prototyping
for volume-produced products.
 Consider the internal structure of a product, and
number of components.
Rapid prototyping (RP) benefits trials, testing
and final part manufacture
 Consider reduced development time and costs, and
user trials.
Compare SLS, LOM and FDM rapid
prototype processes.
 Consider…
 Speed
 Time
 Costs
 Accuracy
 Surface finish.
Describe different design contexts where SLS,
LOM and FDM would be applicable.
 Consider…
 Quality
 Cost
 Accuracy of outcome.

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