Automated off-line programming for Rapid Prototyping using Gas Metal Arc Welding

Abstract

Rapid Prototyping is a recent CAD/CAM based manufacturing technique which
\nproduces prototypes of components in a fraction of the time normally required. This
\ntechnique normally involves drawing the part as a 3 Dimensional solid model using a
\nCAD
\nprogram and then 'printing' it in 3 Dimensions. The raw material can be a
\nphotopolymer or thermoplastic which solidifies when in contact with light. Other
\nmaterials are available
\nalthough producing the final parts a 100% metal is not very
\nusual.
\nSome disadvantages of these techniques are:
\na) 100% metal prototypes cannot normally be made directly.
\nb) only prototypes can be produced instead of the final component.
\nc) machine size limits the size of the final component.
\nd) very thin layers are deposited. This makes the build up more time consuming and
\nmostly suitable to small components.
\nThe main
\nobjective of this work was to overcome these disadvantages by creating a new
\nRapid Prototyping technique using Robot Fusion Welding.
\nIn the
\npre-production phase, it is important to make a prototype not only for
\nvisualisation but also to test and assess it in its real function. Therefore, prototyping in
\nresin a component which is going to be made in metal has no use for assessing purposes.
\nThis
\ntechnique, besides making the prototype in metal can also be used as a production
\ntechnique to make the real usable final component. It even allows the use of different
\nmetals
\nalong its structure in the welding filler wire is changed. This makes it possible to
\nhave different structural characteristics in the same component a required.
\nNone of the
\nslicing algorithms developed for other Rapid Prototyping processes were
\napplicable to this new technique and therefore a new slicing concept (and routine) was
\ncreated
\nspecifically. I addition, an interface for off-line programming and quality
\ndocumentation was evolved. The technique developed has been tested by fabricating
\nseveral 'test'
\ncomponents and both the dimensional accuracy and component integrity
\nhave been evaluated and proved to be successful.