GearHeads Corner

DanL wrote: guys what would be better a 445nm 1400mw laser or a 808nm 2000mw laser as I can get both for the same prices they both have TTL controllers with them and I have seen the 445nm working if a 808nm would be better than a 445 I would get one with what Tweakie said about them it sounds a safer laser to use sort off

Hi Dan,

I have absolutely no idea and I think that only you can decide which will be best for your application.

These are not mine just recent work by others as an example?

Analogue laser engraving using 455nm on birch ply by Jeff  http://kiskz.ucoz.hu/_fr/2/0424911.jpg
TTL laser engraving using 808nm on glass mirror by Dave http://kiskz.ucoz.hu/_fr/2/7431100.jpg

Tweakie.

thanks Tweakie

tweakie wrote: I have absolutely no idea and I think that only you can decide which will be best for your application.

If your application is general screwing around^^^^^^^^^^^^^^^^^^^^^^^self education then IR is somewhat safer and a better first attempt?  Most of my gasket paper is dark colored so either blue or IR has a good chance of working - or the auto parts store will have something else that might.

Kirk

art how do I add images to a post

DanL;

When you hit reply, click on " additional information" bottom left.. There you may add images..

Cheers
Bob

Thanks bob

This is how I think I will make the head and heat sink for my laser

After hemming and hawing (or perhaps we could call it deep introspective thinking and reviewing...) I just ordered one of those (claimed) 40W Chinese K40 Lasers from eBay, for not a lot more than the 2W solid state diode version I'd been looking at earlier.  It's supposed to ship out of California, so maybe in a week or so I'll see just how good a decision that was.

Kirk

good luck with that at lest you know if the controller is bad there is a good replacement

Yes, many choices for replacement controllers, from laserized Marlin on an arduino to smoothieboards to Mach3/4, with a lot of stops in-between.  From comments in the K40 G+ group and elsewhere even the Moshidraw controller and software might be getting better and be good enough for a while.  Remains to be seen, until then it's a project in a blue box.

First it has to get here without a lot of glass fragments rattling in the box.

Kirk

Kirk:

Ill keep my fingers crossed for you. :)

  Let us know how it works out. :)

Art

ArtF wrote: Ill keep my fingers crossed for you. :)

Thanks!  Mine are crossed too.   I've got a few celtic knot laser patterns ready for testing.

It'll help fill the wait time until I can balance my checkbook with Auggie :)   Well, if ignore the honeydo list, that is.

FedEx says it's coming tomorrow.  I'm taking a break from building a workbench to put it on (ignoring that honeydo list again...), simple steel frame with a 2x (as in 2x6/2x8, must be 50x for you metric guys) top.

I'm sure it won't be as good as tweakie's (the only laser I've ever seen working) but hopefully it won't become a new fish reef in the lake down the road.

Kirk

The laser has landed!  After unpacking, fixing a couple loose screws, a quick alignment test (almost, not quite, needed a bit of adjusting), and installing the included LaserDRW I fired it up and engraved a Celtic knot pattern on cardboard.  Not the best looking results, but it proved it's working!  No outside venting, the window I was planning to use was caulked shut so I need some driver vent hose to reach an unsealed one, so I didn't get very adventurous.  Still, it'll engrave or cut cardboard on very low power, and I did a little practice Plexiglas engraving with some of the kid's drawings.  I'll try Gearotic DXFs with the included sw next.

It came double boxed, almost 2" of foam sheet around it, and the tube had (synthetic) foam rubber pads to protect it.  Using about a 4 gallon drywall style bucket for the cooling water (no leaks), and our soft tap water.

Couple pics attached.  I took some unboxing pictures that I'll post somewhere, too.  I'll seek out some dryer vent hose, distilled water, some RV antifreeze, and a bigger water reservoir tomorrow.  Flow switch and other goodies ordered, need to 3D print an air assist nozzle.

Kirk

Thanks for pics  I had no idea how big a laser unit was - I probably can't afford it anyway but it looks pretty compact.  Lots of smoke?

John

Kirk:

Excellent. I see the software actually varies the power over the run based on greyscale, I wish mine did.
Ill be interested in comparing cut power and depths with you. Let me know when you figure out speed
at 100% power to cut say 4mm acrylic or so.. Id be interested in your results.

In my experience, with a 40 watt even running a lot, a buck of water is fine, even it will not heat up.
Id just feel the water occasionally to be sure. I find it a lot more forgiving that youd think. I added
a full litre of windshield antifreeze to my bucket...I found that worked great last season..didnt use water
at all. 

Art

John T wrote: Thanks for pics  I had no idea how big a laser unit was - I probably can't afford it anyway but it looks pretty compact.  Lots of smoke?

John

It's 32 x 20 x 10".

You'd be surprised (I was) at the price, $365 US delivered.  The eBay prices vary quite a bit, I ordered it on Friday with free shipping, and on Monday it was an additional $35 to ship.  There's a large number of sellers that ship from a US warehouse, but I hear they are mostly the same two Hong Kong based companies.  The machine was made by the Liaocheng Shenhui Laser Equipment Co., Ltd., which I read makes most of the K40s.

Wife complained about how smoky the basement was.  I really need to get some dryer vent hose, rather buy some more than unseal the formerly leaky window.  It's now under a porch and doesn't let any light in.

Art, the software docs are essentially non-existent, can't even find any in Chinese to translate.  There's a dpi setting, so maybe they control grayscale that way.  It could be interesting to set it to something like 10 dpi (default is 1000, not sure why they have dpi when everything else is in mm) and see if I can see the individual dots.

LaserDRW won't import DXFs, but they also include a copy of CorelDraw 12 (from 2003) with a plugin.  I did a quick eccentric gear and it did the top half of the gear; didn't get a big enough piece of scrap cardboard to fit the whole thing.  It was very slow doing so, but there were different board numbers configured.  With the Moshidraw board/driver it'll do that if the board type is wrong, so I'll be trying it with the same board number as the non-plug in version.

The software includes a run-in test that will run it back and forth over the same axis.  I get 310mm X and 210 Y (300x200 was the claim) without hitting the stops.  I'm going to lube it with the "dry" bike lube I use on the 3D printer and if that makes any difference.  Max speed is 500mm/sec, set it any higher and the software sets it back.

There's a spring loaded clamp for smaller pieces, not quite sure what to do with bigger stuff yet.  Lots to experiment with and learn about.

I'll try some squirter juice instead of antifreeze/distilled water.  Is the cheap blue stuff is good enough, or do I need to go with the premium RainX premix?

Kirk