Good Buy? Paper Craft Laser Cutter

[2_many_hobbies]

Hey, I am trying to design a paper cutting machine, the goal is to cut card stock (~0.013" thick) and do it with as little burning as possible.

I found this on ebay, He is selling 1.6W,2.4W and 3.2W ones and their quite reasonably priced given they come with a housing, optics and a driver. EBay Laser I know its more expensive than a bare laser diode but even the 3-12W diodes are listed for $50 but the all jump to $100+ in the last few hours while this guy is buy it now with 10+ stock.

Will this suit my needs? Anybody know of a video or pictures of a <5W laser cutting paper to I can see my expectations?

My idea was to eventually make a new housing for this laser out of aluminum and put a peltier device or two on either side so I can up its output safely.

Thanks!

[zax15uk]

It depends on the spot size, which is one parameter they don't list.

It should be pretty small (perhaps 60um) for 808nm wavelength with good optics, which is over 6 times smaller than a typical CO2 spot size (150um).

This of course means the power density is 6 times also - sound good so far.

Well now for the bad news, 808nm wavelengh energy isn't absorbed as well by organic materials (paper) compared to the 10600nm from a CO2 laser, so this means you'll get more burning (charred edges). That being said, 4-8W of CO2 will easily cut the card stock at a reasonable speed (minimal charring) so 3.2W of 'red/ir' should do a reasonable job - but I don't know for sure.

I've used 1W 808nm for engraving wood, well it wasn't 'engraving' as such - more like pyrography. It would cut paper, but not with a very clean edge.

Zax.

[2_many_hobbies]

Hmm, The main reason I didn't want to use a co2 setup is their friggin expensive. You can easily get 20W+ tubes for $100 but add a power supply for $200 and then optics and your pretty much at $500. If I decided I liked laser cutting and wanted to upscale then I would defiantly go for it.

Right now the XY Table im going to re-purpose is only 4x6" so a co2 is quite overkill.

I did find this one used 20W co2 system with all components but with no documentation on how to control it im not sure..

Ill keep searching but its pretty hard to find diode lasers >5W and ones that do need liquid nitrogen not to melt down. Anyone here build a high wattage diode system?

[2_many_hobbies]

All right I waited on the $122 co2 setup and last 90s it jumped to $290 so yea I didn't buy that one... That and co2 tubes are very large, like 700mm long and I cant fit that on my table not to mention it would be overkill for my 4"x6" working envelope.

Now im gonna try to piece together my own setup. All the higher power lasers are DPSS multi-emitter setups and I have no idea what I would need to focus them. Can anyone tel me what all components I will need to focus these types of lasers?

20W DPSS 1 / 20W DPSS 2 / 20W DPSS 3

This is the only 'focusing' optic I could find for 808nm but I thought you needed some odd shaped ones for collimating a laser bar.

And the last thing is how to drive these suckers, I would assume you feed a PWM signal into a control to regulate either the duration the beam is on or the current applied to the diode. I can easily make high current controllable sources but is their any drawings or projects that someone has made one already?

[kling8]

If your not using CO2 to operate laser, what is the power source that your using? Electric? Is CO2 that expensive to buy? Do the CO2 lasers use a lot of gas?

[zax15uk]

2_many_hobbies, look for fiber coupled bar diodes and then you can use standard optics, if not you will need a special lens to collimate the output.

PWM at high current isn't easy (it sounds like you may have experience), any voltage spikes will result in a dead emitter. Most of these diodes can run at lower power in CW mode, which is obviously easier and would allow testing and possibly a shutter design beam control.

Zax.

[zax15uk]

kling8, laser diodes are just another type of laser that emit a different wavelength.

Nd:YAG or Nd:YVO4 (vanadate) are examples of these solid state lasers.

Low power CO2 lasers are typically sealed gas, so no the issue isn't cost of the gas.

They're all 'electric', CO2 isn't the power source just a medium. I would suggest http://www.repairfaq.org/sam/laserfaq.htm#faqtoc as a good place to learn more about the different technologies and their uses.

Zax.