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Information Sheets
Rapid Manufacture and Repair
Lasers are playing an increasingly important role in rapid manufacture, rapid tooling and component repair. The process involved is laser-assisted deposition, an example of which is laser cladding.
Building a cylinder using a laser deposition process
In the laser-assisted deposition process, a material is bonded to a substrate by introducing it into a laser-generated melt pool on the substrate. Methods of delivering the material include pre-placed powder, blown powder (either coaxially or side feed) and wire feed. The current most popular method is coaxially blown powder, which allows cladding in any orientation.
The process can be performed using pulsed and/or scanning continuous wave (CW) lasers. When the laser pulse ends (or the CW beam moves on) the melt pool quickly cools, resulting in a fusion bonded layer with superior bonding characteristics and reduced porosity compared to other thermal processes, and has the advantage of a reduction in overall heat input.
This part, consisting nested hexagons of edge length 1cm and 2cm high, was built in approximately 40 minutes. It is shown in ‘as built’ form before any post-processing
Adding layers of cladding on top of one another in pre-determined vector paths allows the build of three-dimensional parts. Since the layers are fusion bonded to each other, fully dense parts can thus be made. The manufacture of different part only requires changes to the CNC control equipment program rather than a change of tools or moulds; this is known as ‘soft tooling’. At present, most parts produced this way need some post-process machining to finish them to required tolerances.
This double-walled cylinder has been sectioned to show internal spacers between the walls incorporated as part of the building process. (Parts shown are 6cm high and 3cm OD)
Points of particular interest include the fact that building parts in this way allows the incorporation of defined voids (as in the part pictured left) and the ability to slowly change the type of powder being used as the part is built, resulting in a gradual change along the part from one material to another.