Net shape Functional Parts Using Diode Laser

Abstract

Manufacturing processes, such as cutting, drilling, soldering, marking, forming 3Dsintered parts from metal powders and laser vapor deposition, are now well established practices using matured high power lasers like Nd:YAG, C02 and Excimer lasers(l). These lasers are bulky, inefficient and expensive. Semiconductor diode lasers, if wavelength is not a disadvantage, hold the potential of creating a major cost/convenience breakthrough in these and other new manufacturing processes such as growing integrated opto-electronics devices etc. They have the potential to initiate a mini industrial revolution because they are compact, have high wall-plug efficiency (50%) and above all, they can be mass produced (like computer chips). It is important to note that almost all laser material processing can be carried out ifthe intensity available can cover the range from 103 to 107 W/cm2 . Fortunately, microscopic as they may be, even low power diode lasers emit reliably at 106 W/cm2 . The hurdle that needs to be solved is coupling energy from a large number of diodes to obtain high total power without losing much oftheir inherent brightness and yet keep the system cost low. Price of high power laser diodes have already come down dramatically over the last five years; further reduction is expected as the volume market keeps increasing rapidly. Current commercial devices are mostly oftwo types: (1) fiber coupled arrays and (2) two-dimensional stacked arrays. We are using both types. We believe, the ultimate high brightness and high total power at low cost will be achieved by 2D array ofbroad area surface emitting lasers. We will present the results of our various activities using 30W (980 nm, spot size - 600 ~m), 10 W (860 nm, spot size - 50 ~m) and 60 W (810 nm, spot size - 700 ~m) fiber-coupled cw diode laser and 50 W (930 nm spot size -700 ~m) free space diode lasers on: (1) fabricating 3D SLS parts directly from metal/ceramic powders using CAD/CAM design, (2) laser assisted selective area vapor phase deposition of amorphous SiC and ShN4-rod, (3) Pb and Ag soldering ofsimple electronic parts, (4) surface hardening ofstainless steel ribbon. INTRODUCT