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Hi! I'm gong to upgrade my small laser engraver so that I can cut 3-4 mm plywood. I don't mind if it's little slow cutting, but it have to run continuously for one hour or two. I have been in contact with dtr-lpf on eBay.com about this laser:
2W 445nm M140 Blue Laser Diode In Copper Module W/Leads
(http://cgi.ebay.com/ws/eBayISAPI.dll...:X:RTQ:US:1123)
TheIs it possible to cut plywood with this laser or do you have a better suggestion?
Best Regards / Jimmy Alenius
i use a 60W co2 laser to cut plywood. it works very very well.
i don't think you would be able to do that with a 445 diode.
http://youtu.be/3Ip-7TentM8
Quote:
Originally Posted by Jimmyalenius
Ok, so not even if I cut it very slow?
you can try it, but i would be surprised it it worked.
i recommend you use also use a jet of compressed air colinear to the laser beam to help blow smoke and junk away from your cut.
Quote:
Originally Posted by Jimmyalenius
You'd be better off with a soldering iron on a stick.Quote:
Originally Posted by Jimmyalenius
So the only option is a CO2 laser?
... the diodes with 445nm @2Watts are perfect for marking wood, but cutting is more problematic - I've cut 5mm Balsa-sheets with 4 passes, but cutting 3mm birch plywood stopped at the first glue-slice ...
Viktor
Ok! How about those 5w lasers that's on eBay. Is it still too less power to cut wood?
Another problem I got is about color of the material that's being cut. White wellpap is impossible to cut through with my tiny laser. Brown or black is much easier. Is white wellpap possible with a 2w laser?
Thanks for answering all my questions. I'm new to this, but wants to learn :)
Regards / Jimmy
... 5Watt @445nm would be much better or more usefull, but most ">3W-diodes" are simply overpowered above their safe limit, so with drastically reduced life-time expectation ... sometimes only some ten hours, until they'll dying for overheating!
You can cut white paper with >1W @445nm or >300mW @405nm ... for "wellpap" you'll have to run several passes and maybe adjust the Z-heights per pass too ...
Viktor
Yes, my machine is a cnc mill (x, y and z) so there is no problem to lower the laser for every pass. So the big challange is to find a 5w/445nm that is native 5w. Back to eBay...
that will be a challenge... 5W 445 diodes do not exist. you would have to combine multiple diodes.
Quote:
Originally Posted by Jimmyalenius
Contact this eBay seller and ask if it's possible with any of their three 808nm laser cutting setups. I use 445nm diodes for photo engraving and I'm not familiar with the 808nm diodes.
10W
http://www.ebay.com/itm/Industrial-8...item2a210aa2a6
15W
http://www.ebay.com/itm/Industrial-8...item2a210b4791
20W
http://www.ebay.com/itm/Industrial-8...item27db1d1295
... NIR-diodes need much more power than VIS-diodes to do the same job -- a 445nm@2Watt-diode is in terms of engraving and material capabilites more usefull than a 975@9Watt-diode ... and 808nm-diodes are not so much better than 975nm types ...
Here's an example for a 6x 445nm-module: http://www.photonlexicon.com/forums/...505#post282505
Viktor
you're rapidly approaching the cost of a cheap co2 tube and psu with that system and you have some extra alignment complexities.
Quote:
Originally Posted by VDX
... I won't suggest to DIY a multi-diode-head for engraving -- you'll loose much of the accuracy of a single diode (one focussed 445nm@2W-diode - spotsize = 0.05mm, 6x-head - spotsize = 0.3mm) ... this was only meant as example of an actual laser-module with >>2Watts of power ;-)
With the sampling/sourcing/refurbishing of lasers for my experiments at home over the last years I've got all sorts of lasers from diodes, pulsing NdYAG's, TAE-N2-lasers, fiber-leasers and CO2 with powers from some Watts to Kilowatts -- and awaiting two NdYAG's with 10Megawatts (300mJ and 800mJ @8ns pulses) at 1064nm and with frequency-doubling to 532nm for more 'serious' testing with material-processing ...
Viktor
Sometimes you can find Synrad 48-1 10W CO2 for as little as USD300 or so, just be creative whe searching because people mislabel them on ebay. Also call/email companies that do engraving and cutting, sometimes they have spare lasers for old machines, Synrads with RF transistor failure or underspec units that you can get for cheap! Some engraving types do not know/care anything about lasers or technology and are happy to get rid of old junk! :)
I agree that the CO2 is the way to go. We have a couple of old 40W CO2 lasers that were originally medical units that include an articulating hand piece that brings the beam to a convenient focus. Years ago my kids used one of these as a "high tech" wood burner to cut yard signs on clear pine. 40W is inexpensive for a sealed tube and driving these is pretty simple as well. Many will run with simple high voltage AC current of several tens of mA. The secret to a deep cut is removing the black char that protects the underlying wood from a subsequent pass. A high velocity air jet would probably perform this function fairly inexpensively.
Go with the Co2 Laser with an air assist gas feed. 40 Watts of CO2 is very nice, and more power is better in this application. Otherwise you will have a very low federate.
Make sure you have a Silicon, Germanium, or ZNSE lens for the Co2 Laser. It emits a far infrared light that does not pass through glass lenses. It will crack a glass lens.
Also, plan to vent the fumes. When I started with lasers, I tried using a 100 Watt medical CO2 laser hand piece to carve my name in a plank of pine. The fumes and tar given off were horrible, very toxic, and I found myself choking on them. Most cutting systems thus have a large blower pulling the fumes out of the room.
Blue and Green light basically bounces off wood. This is why blue light based engravers have to have a very tight focus. The tight, tiny focus is not good for burning through carbon char on the second pass, when cutting.
Steve
Here is someone that does fine cutting in wood using a 405nm & 445nm LD, but has air assist & long focal length lens on his setup. He is not cutting 3-4mm though, but with the air assist, it may with a couple of passes. I believe the air would blow that carbon char away for any extra passes.
There is another person cutting wood there with a 445nm also, but he cuts from both sides without air assist.
http://hobbycncart.com/forum/63-151-46
http://hobbycncart.com/forum/63-151-47
This machine cuts several types of materials with a 445nm, but the thickness and passes depends on the material. There is a chart in the "Updates" detailing this.
https://www.kickstarter.com/projects...utter-engraver
... cardboard is sometimes better than wood ;-)
Attached some samples of fine-cutting 0f 0.3mm thick 'golden' cardboard I've done to demonstrate the abilities of the 445nm-diodes:
Attachment 44169
Attachment 44168
Attachment 44167
I find that doing multiple laps while dropping the Z axis a wee bit tween, helps get it done. It also helps to cut on a grid or such, so the laser can cut through. Lightburn has some other options for cut through, where the path hangs a little at the start and end of each cut, so the laser has just a wee bit more time to dig a bit deeper. Have not played with the settings enough to determine the real value.
Attachment 56881Attachment 56882
This is 3mm Birch that I ran at 250mm/m@100% with 7 passes and a half mm of Z drop each pass.
Cheers
Anjin