C 4 – R A P I D P R O T O T Y P E M A N U F A C T U R E

 A technique that uses a fluid support structure that can be washed and drained away.




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 resin.
The platform then moves down by a layer thickness so the next layer can be printed.

 A technique that uses break-away supports.



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, 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
(FDM).


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.



SLS is a 3D printing process based on sintering.
A CO2 laser is used to sinter a thin layer of heatfusible powder that gradually builds up the 3D model.

Compare wet and dry rapid prototype techniques.


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.