Abstract:
Rapid Prototyping is a recent CAD/CAM based manufacturing technique which
produces prototypes of components in a fraction of the time normally required. This
technique normally involves drawing the part as a 3 Dimensional solid model using a
CAD
program and then 'printing' it in 3 Dimensions. The raw material can be a
photopolymer or thermoplastic which solidifies when in contact with light. Other
materials are available
although producing the final parts a 100% metal is not very
usual.
Some disadvantages of these techniques are:
a) 100% metal prototypes cannot normally be made directly.
b) only prototypes can be produced instead of the final component.
c) machine size limits the size of the final component.
d) very thin layers are deposited. This makes the build up more time consuming and
mostly suitable to small components.
The main
objective of this work was to overcome these disadvantages by creating a new
Rapid Prototyping technique using Robot Fusion Welding.
In the
pre-production phase, it is important to make a prototype not only for
visualisation but also to test and assess it in its real function. Therefore, prototyping in
resin a component which is going to be made in metal has no use for assessing purposes.
This
technique, besides making the prototype in metal can also be used as a production
technique to make the real usable final component. It even allows the use of different
metals
along its structure in the welding filler wire is changed. This makes it possible to
have different structural characteristics in the same component a required.
None of the
slicing algorithms developed for other Rapid Prototyping processes were
applicable to this new technique and therefore a new slicing concept (and routine) was
created
specifically. I addition, an interface for off-line programming and quality
documentation was evolved. The technique developed has been tested by fabricating
several 'test'
components and both the dimensional accuracy and component integrity
have been evaluated and proved to be successful.
