How align IR beam (co2) with visible beam (red dot laser) ?

[etienne delcuve]

Hi everybody,
I want to build a co2 laser +/- 40w for wood engraving.
Before I buy something, does anyone have pictures or good links who explain me how to align IR beam with red laser. the tube I'll buy is a sealed one with integred and aligned mirrors.
I want to align outgoing ir beam with red laser to see "where I'll shoot" and then align with the beam delivery.

here a little video of wood engraving I make with the 200mw red laser:

"http://fr.youtube.com/watch?v=7dyoL5W1pBY"]YouTube - laser cnc


I want a more powerfull laser (co2) to increase engraving speed.

best regards
(sorry for my english ;-) )

etienne

[zax15uk]

You'll need a ZnSe Beam Splitter/Combiner. The lens is AR coated for CO2 so the laser goes straight through, but the red pointer comes in at 45deg. and goes out along the CO2 beam path.

There are also options where the CO2 will be reflected at 45deg and the pointer goes straight. You could use this type instead of a mirror.

[etienne delcuve]

thank you !

etienne

[swarf-maker]

I'm curious where to find a 200mW laser device? I would also like to do some wood burning similar to this.

Is there more information available about your laser/cnc setup?

Thanks,
Swarf

[zax15uk]

You could remove one from a DVD burner, or buy the same diode new from ebay. If you want to do serious burning/cutting you'll need a CO2 laser.

[swarf-maker]

Do you think a diode removed from a DVD burner could do wood burning like the video? I assume it could and would like to try this with an existing CNC machine. I also assume the video was shown running at actual speed with the stated 200mW laser diode.

Swarf

[zax15uk]

I have several 160mW diodes which can be over-driven to 200mW+ with adequate cooling.

When focused correctly it will burn light wood, cut black plastic tape and melt expanded polystyrene but I soon upgraded to a CO2 laser.

I'm not sure what the material is in the video but it's certainly possible at the speed shown.

The video specifically says the laser was from dealextreme, but they no longer ship lasers to the U.S. due to customs restrictions. You can find them at several other vendors and on ebay.

You can get similar and perhaps better results using a hot iron to burn the wood - which could easilly be added to your CNC (I did it).

Zax.

Do you think a diode removed from a DVD burner could do wood burning like the video? I assume it could and would like to try this with an existing CNC machine. I also assume the video was shown running at actual speed with the stated 200mW laser diode.

Swarf

[MonoNeuron]

Hi Guys,
To get the red pointer aligned to the laser beam path is very simple.
Set up you laser how it will finally be on your table exactly parallel with the axis you have chosen then place a piece of wood about 2 meters away and in line with the laser path.
Fire a very low powered shot of the laser at the wood so it leaves a small round black/brown spot on the wood and don't move anything afterwards.
Then align the red pointer to the exact center of the spot.
Do this at about 500mm away as well to get the alignment exact.
If you set up the combiner mirror so that the laser beam passes right through the middle of it then the red pointer is aligned to the center of that, then it should go very well.
Then you know the red pointer will be spot on and you can then set up the rest of your mirrors knowing that it will be right on the mark when you turn it on and can burn the crap out of everything.
Easier done than said.
Rich.