Re: [CAD_CAM_EDM_DRO] added laser cutter to my mill (pics)

skykotech wrote:

>CAD_CAM_EDM_DRO
> ^
> LASER :-)
>
>I just added an attachment to my cnc mill. It is a 10 watt Synrad
>CO2 laser (doing about 17 watts, go figure). I got it for free from
>a semiconductor marking machine that was tossed in the dump. The
>lens is a 1 inch dia. 3 inch F.L. ZnSe curtesy of ebay ($25). I am
>not really positive it was required to mount the lens as far from the
>co2 laser as I did (about 20 inches) but I read that the beam from a
>Synrad laser is square in profile at exit and becomes round and
>gaussian at about .6 meters from the laser output. Anyway, it seems
>to work O.K. In the pics I cut 1/8" basswood at 60IPM, black felt at
>120IPM, 1/8" acrylic at 40IPM, 1/8" spongy foam at 100IPM, and 1/4"
>acrylic in 2 passes at 30IPM. I am using dry shop air at about 20
>PSI into the lens/nozzle assembly I machined on the same mill. I
>used a ring of Indium wire to form a seal/cushion for the lens
>(overkill?). I tried using nitrogen, but didn't see much difference
>than air (and I saw my nice bottle of 2500 PSI 99.999% N2 dropping
>all too rapidly :-)
>
>

Obviously no need to use 5 nine's N2 to keep your lens free of spatter.
Air should work fine in all cases except where the material might burn.

>Right now I am just hitting a footswitch when I want the laser to
>come on (couldn't wait and just had to see it cut something). My
>mill runs EMC and I am going to get a second parallel port and use
>I/O from it to turn the laser on/off. What would be a good thing to
>use? Does coolant on/off have latency?
>
>

There was a big thread on this some time ago. One way to do it is to
have coolant or other aux I/O enable a velocity-controlled power regulator.
So, as the material accelerates, the laser intensity is turned up.
(Your laser
may not have variable intensity.)

Anyway, the thrust of the thread was that EMC's aux I/O would cause a
hitch in
the motion, I think.

Man, did you get LUCKY! Wow!

Jon