Re: [CAD_CAM_EDM_DRO] Laser "route" Printed Circuit Boards

Yep, I was gonna say this. Copper is a near perfect IR laser reflector,
and also a great thermal conductor to remove heat from the cutting zone
which keeps it from getting cut.

That's not going to work because if the laser power were upped high
enough to cut copper, it would cut the FR4 material 100x faster once it
pierced the copper, making the Z-depth uncontrollable. A few
milliseconds too little and the copper isn't cut, a few milliseconds too
much and it blasts all the way through the FR4.

Also where would the metal go? It may not yield a clean cut, the molten
copper might ball up on the border and then SMD components won't lay
flat. Or the molten metal might spray onto the burned FR4 creating a
conductive surface.

Note that laser cutting is most often for 2D cutout applications. 3D is
much trickier, because unlike milling the Z-depth is not a directly
controlled parameter. For 3D apps milling is often preferred.

Danny

Jon Elson wrote:

> Michael Fagan wrote:
>
>> Yes, this is doable, but the issue is that "small" is about 50 watts.
>>
> 50 W is great for cutting plastic. I don't think it will do a DARN
> thing to any
> metal unless you just set it there for a minute. Applying a black
> coating to the
> metal may help it absorb energy, but shiny copper is just about the worst
> POSSIBLE surface to absorb IR. Also, copper is a GREAT heat conductor, and
> you want the heat to stay put for cutting. I think you need a MUCH
> more powerful
> laser, and possibly a much more difficult wavelength to burn away
> copper. Once
> you've pierced the surface, the burning epoxy behind it may help absorb
> the IR,
> so you can cut the power back a bit, or just up the feedrate.
>
> You should be able to do some web research on what you CAN cut with a 50W CW
> CO2 laser, there are a lot of outfits selling them. I think they all
> recommend them for
> plastic, paper, rubber stamps, and similar materials, which are probably
> something like
> 100 times easier to burn than copper.
>
> Jon
>
>
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