An ideal application for the HPDDL
is large surface area laser cladding. As shown
in Figure 1 the line of laser light along the
short axis is moved perpendicular to the long
axis. The biggest benefit of HPDDL laser cladding
is that the unique line source allows the user
to produce clads with a controllable width without
scanning. COŠ÷ and Nd: YAG lasers have a smaller
spot; thus the laser must be scanned over the
cladded area. The wavelength of the HPDDL is 808
nm, compared with 1.06 m m for a Nd: YAG laser
and 10.7 m m of the COŠ÷ laser. The shorter wavelength
of the HPDDL allows for higher absorption into
the material being cladded, therefore a higher
process speed can be achieved. Both COŠ÷ and Nd:
YAG lasers often require binders when using pre-placed
powders. The use of binders often leads to porosity
due to the evaporation of volatiles during the
cladding pass4. The HPDDL system does not necessitate
the use of binders to hold the powder together
before a cladding pass. Another advantage of the
HPDDL is that the thermal input can be precisely
controlled thus yielding minimal dilution and
a small heat affected zone.