Test laser system

[nokillzone]

Hi all,

I seen this video on youtube

http://www.youtube.com/watch?v=k-1vRb9XZTc

So what laser would work better

http://www.steminc.com/laser/SMM22808E1200.asp

or

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180343406074

is there any difference between them. If this works i might spend money and make a CO2 system.,
Thnaks!

[zax15uk]

You may be able to use the IR diodes in those listings (depending on your application) but make sure you have suitable eye protection.

I believe the laser in the youtube video is from a DVD burner, typically 100-150mW but with suitable cooling you can push them to 180-200mW or more for short periods. That is plenty to cut foam, thin dark plastic or burn wood.

Zax.

[nokillzone]

well i seen on ebay 1W laser diode for 60 buxs or so ..

I hope that can cut paper maybe? but mainly mark paper,

Maybe cut thin plastic that is used for barier insualtion for drywall.
One Wat laser should be better and more powerfull than DVD laser no??


i dont know what results i would get with mach3....


But i dont know what cooling / what lense to focus the beam i would need .. ???

[zax15uk]

Output power isn't the only variable, wavelength and beam profile are also important. You also need to consider the power supply / driver circuit. Optics would be cheaper on these diodes compared to a CO2 system.

I'm not sure what the barrier plastic is made of, but it could be PVC in which case I would not recommend cutting it with a laser due to chlorine content.

Mach3 would be a good choice.

Cooling could be as simple as a heatsink, or for higher power you can add a fan or TEC system.

Zax.

[nokillzone]

How would i find out this info(wavelength and beam profile)?
For power supply/ driver circuit i would buy all ready made 3 motor driver board from ebay to drive 2 motors x and y, and on the third i would hook up the laser?

Im in canada so geting this diode from usa wouldnt be a problem? Its not like a co2 tube? any one have any experience with this?



Thanks!

Also the laser diode on ebay says......
"This is a high power 808nm laser diode. I sold the first batch of these at 500 mw because I didn't have a power meter to get an exact reading, but several buyers have confirmed output of 1 watt. The diode will instantly start burning plastic at a close distance. The burn mark shown on the left took about 5 seconds and the burn mark on the right took about 10 seconds and it burned completely through the plastic. This testing was done with 2 D cell batteries and a 1 Ohm wire wound resistor. However, for peak performance, 2.2 volts at 1.2 or 1.3 amps is ideal"

[zax15uk]

Well the wavelength is easy, 808nm for these IR diodes. The beam profile is more difficult but usually an ellipse or line on diodes like this. It is very difficult to get a round dot from them with basic optics but you can focus the ellipse down to a pretty small 'dot' looking spot.

I'm not sure about your idea of powering the diode from the stepper motor driver, it could work if you connect it indirectly but think you'll just blow the diode and won't be able to get full output either.

The ebay listing states 2.6W input for 1W output, that sounds about right. Most laser diodes are between 25-35% efficient, with some high end ones approaching 75%.

Zax.

[nokillzone]

This video is my Ultimate goal.

http://www.youtube.com/watch?v=gnZ26ZAfo4c

Well as well as cut stuff.

The guys website dose not explain how to control the Laser and how to wire it all together

http://c4r0.skrzynka.org/_hv/index.php?page=lasers/cnc2

He uses a Diode from a DVD-RW 16 or 20x
But wouldn't the 1W laser work better???

Thanks allot zax15uk for your replies!

[zax15uk]

You would certainly be able to burn using these diodes, and cut thin dark plastics or melt foams. If you want better results a CO2 would be the answer, but of course more expensive.

A laser diode requires a stabilized voltage (no spikes) and a constant current source. A basic and cheap driver can be made using a variable voltage regulator like an LM317 in current mode. If you connect the control pot to a small motor it can be controlled indirectly from a stepper driver. A transistor switching circuit for pulse mode would be better but more complex to build.

A 16-20x DVD-R diode would typically be ~250mW or more at 650nm. That means you have a visible red dot, making it easier to align and focus compared to the IR diodes.

IR diodes are more dangerous - your eye doesn't have any blink response to the invisible beam. Eye protection is necessary for either laser.

Zax.