laser welds intrinsically tend to be work hardened, and sometimes a
bit brittle, and this seems especially so with the non-precious
metals, or various white metals other than platinum. Also, watch
out, while welding for those thin spiderweb like lines appearing on
the surfaces of the weld spots. Those are cracks, which can easily
extend deeper, or may already extend through the weld, meaning the
weld will fail if they’re not corrected.
A couple steps you can take to help.
Use argon sheild gas
Use lower power, but longer millisecond weld pulses. they tend to
be slightly more self annealing in my experience with some metals.
If your laser offers pulse shaping, play with those settings to
eliminate weld cracks.
Build up the weld to a thicker cross section than the metal you
repair. Don’t trim it totally flush afterwards. leave the weld a
bit of a lump.
Consider using a filler metal that’s as ductile as you can for the
welds, rather than necessarily an exact match. I usually use 18K
yellow gold for welding any yellow metal frame, even when the frame
is base metal. The welds crack less than with lower karats, or base
metals. And I’ve now and then used platinum filler wire to weld
plain white metals, or for a lower welding temp, palladium white gold
(not nickel white gold, which is quite prone to weld cracking)
Test your weld when done. Flex the thing a little and see if it
holds for you. If it’s gonna break, better it does it while you’re
still sitting there at the laser than later with the customer holding
Understand that some of the metals they make glasses frames from
simply aren’t good candidates for laser welding, and you may not be
able to tell before hand. Consider doing this work with a disclaimer
stating that some types of frames simply don’t weld very well, and
such repair work can be unpredictable…