Cladding

 
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.