I changed the burn power to 90% on the 1st burn & it worked this time. I was probably moving too fast for it to burn. Still not sure why I can’t focus with $32=1. Thanks for the focus script, but I had seen that before & since I am not currently using a Z-axis it does not help me. Maybe I should post a message to the lightburn forum. Here is the test burn I did in a 2x4. The 1st little burn at bottom was previous test before I stopped it.
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It turns out my eleksmaker board is ok & probably the other boards as well. That $32=1 setting got me. Can’t believe I have not found that with a google search. I can’t be the only one with this problem. I will have to post this question to lightburn forum when I get my data in a row. Here is my 2nd test burn for today. I set the size to fit on a 2x4. I used 2 dxf files from this free resource. I took the bear off one file & swapped it with the elk on the oval as I wanted an oval boundary. Wildlife Landscape Scenes | Free DXF Files | Maker Union
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Dave, When turning on the laser for focusing use the full G1F2000S10M3… it should work. Sometimes the F setting is missing and it wont turn on without it. Also with laser mode on all G0 rapid moves will be executed with the laser turned off, so use G1. with M4 the machine uses dynamic power - the laser should only be on if the head is moving, so use M3.
‘Dynamic laser power mode will automatically adjust laser power based on the current speed relative to the programmed rate’ - so if you are not getting 100% power then the programmed rate is set too high for the speed you are attaining, try reducing the mm/min. Your 10000 looks way too high to me.
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Thanks, that fixed it. I changed that 10000 after seeing @dkj4linux grbl settings. I now have:
$110=3000.000 (X-axis maximum rate, mm/min)
$111=3000.000 (Y-axis maximum rate, mm/min)
$112=250.000 (Z-axis maximum rate, mm/min) (not used by me yet)
$120=100.000 (X-axis acceleration, mm/sec^2)
$121=100.000 (Y-axis acceleration, mm/sec^2)
$122=50.000 (Z-axis acceleration, mm/sec^2) (not used by me yet)
Now that my current problems with the laser engraver are solved do mostly to the help from the folks in this forum, thought I would add air assist to this. I have an old air mattress pump, but that thing is pretty loud that I could try, but I wanted something that is adjustable speed & quiet. Aquarium pumps seem to be what I am leaning to. Here is one that has 6193 reviews & one of the reviewers is using it for 40 laser air assist. It also comes with the hose. Does this look like it would work well? Amazon.com : Uniclife Aquarium Air Pump 4 Watt 4-LPM 2 Outlets with Accessories, Adjustable Oxygen Pump for 20-100 Gallon Fish Tank : Pet Supplies
If you’re interested I can chase down a few links but here’s what I did a couple of months ago for my diode laser.
Taking a page from the Omtech 50W CO2 laser I purchased a few months ago…
I devised a similar air-assist setup for my diode laser. Using Onshape I created a nozzle that simply friction-fits the screw-adjustable lens assembly of my diode laser module and accepts a length of 6mm air hose…
which loops around to a quick-disconnect ball-valve…
strapped onto the back of the Z-axis mount…
and then connects to an aquarium pump similar (though smaller capacity) to what’s provided with the Omtech laser machine…
The Onshape design file can be easily adjusted to accept a different diameter lens assembly and/or nozzle length and exit diameter…
and can be found here.
In use, the ball-valve can be used to adjust the strength of the air stream. For engraving, it’s best to use very minimal air-assist (just enough pressure to keep smoke from the lens) and open the valve fully to cut through materials. Russ ( SarbarMultimedia has a zillion videos (mostly CO2 but same air-assist setup) that talk about “everything lasers” and this one might help…
Have fun.
– David
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That looks like a great solution. I have a 2.5W cheapo laser that I hooked up, tested PWM and then I got thinking too hard about air assist. I should really just print this and move on. I have a few aquarium pumps that would work. Thanks for sharing. Very clever and simple design.
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If you want to duplicate what I did, here are the components I used…
the ball-valve…
hose and assorted fittings…
and the air pump…
– David
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I will take a look at those tomorrow. How quiet is that air pump? I got a little carried away today with drawing up a design. I took 2 designs on thingiverse & combined and modified them some. Here is what I have so far. The focusing ring works really well by itself. probably need to simplify it to more like your design.
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I don’t find the air pump objectionable at all. It’s not silent but not loud either… not that I’d notice however – I’m also hard of hearing 
I always set the focus to about 55mm or so from the bottom of the lens assembly… and leave it there. Then I fit my nozzle (about 50mm long) to the lens assembly with the air inlet oriented where I want it… leaving focus about 5mm beyond the nozzle. I cut and use a 5mm step-gauge to then adjust the distance, nozzle to material, on my CO2 laser (no Z-axis)… or use Ryan’s focus script to fine tune using my diode laser’s fully-implemented Z-axis.
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I opted to order the aquarium pump I linked in a previous message & have started working on a mount for it. Since I currently do not have a Z-axis (which I may make a manual one similar to my rolling plotter mount), think I worked out a way to use a modified version of this wheel adjuster with the air assist. Laser focus adjustment wheel by Pawpawpaw85 - Thingiverse . I redrew this in fusion 360 so I could modify it. I mostly just shortened the outside diameter to fit within my air assist mount. I left 22mm wide openings to get my finger in between to adjust. I have to print this air assist with supports, but only in the center. I have 2 screw mounts on the laser but also added a bracket squeeze mount in front as I am not sure the 2 screws are enough to support it. I looked at putting a flat brim at bottom of nozzle & printing from that end, but then I have the overhangs of the rectangle collar which do not have enough room to really taper up because of the screw mounts on the laser. Here is what it currently looks like.
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I adjusted the design a little. I noticed there was less than 45 degree angle on part of the nozzle on 1st print & made the air input angle up to the top of square adapter so only part that needs supports is in the middle. I have plenty of room to get my finger in to adjust the focus and should easily mount to laser on the machine without taking anything off. Pump should come in today. Here is what it looks like attached to my spare laser.
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Some of the air assist nozzles I’ve seen designed for 3D printing actually close over the end of the cone with a very thin layer so that the laser punches through on the first use, keeping the aperture as small as possible. This ensures positive pressure inside the cone, preventing smoke from eddying up against the lens.
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Does enough air get through that tiny hole to clean the burn? Seems like that would be a pretty high pressure of air coming through that might cause other problems.
I’m only reporting what I’ve seen in other designs similar to what was posted above. I guess it would depend on the laser’s focal length and the volume of air you were pumping. These seem to me to have to do 2 things at once:
- Prevent smoke, etc. from degrading the laser lens
- Air Assist which clears products of combustion from the laser impact site and prevents flare-ups
One design I saw had 2 conic sections, one that pointed down close to the workpiece in order to focus the main blown volume for “air assist” and a shorter, blunter cone protecting the lens that got a smaller amount of air from an internal baffle.
Currently my laser engraver is sitting under about 1/4" of dust as it’s been a while since I’ve used it. My personal DIY’d solution was a .035’ welding tip screwed into aquarium tubing and heat-shrunk to a piece of 12 gauge copper wire which was in turn attached to one of the existing laseer head screws. This let me “aim” at the focal dot for air assist, but didn’t provide any lens protection.
Thanks for the clarification and the idea. Now that I have dry fitted this hose with the pump, I can see the volume of air will not be very much. Think I will redesign this nozzle some to make it thinner & maybe a smaller opening in the bottom. Putting this on my laser engraver, I also noticed I need the mounting holes & collar on opposite side so the hose is on the supported side.
This morning I realized a bowden tube might work for this air tube & was happy to see it fit tightly inside the aquarium pump tube. The volume of air coming out of it felt stronger. I changed the design to accommodate it & made the nozzle smaller. The volume of the inside of the nozzle went from 10.52cm3 to mere 2.12cm3. I plan to put a slit in the 1st part of tube connection to wire tie it tight on there. It is currently a 3mm opening at bottom of nozzle and input. I might test printing a smaller hole to see if I can go much smaller than that.
For a quick test, slap a piece of tape over the end and let the laser make the opening.
I might try that tomorrow. I has some little orange dots stickons that might be good, but will try painters tape if I can’t find them. First test fit today looks like I do not have the bracket quite square and laser is missing 3mm opening partially. I changed it to 4mm & added some bumps on corners to make sure it square when tightening bracket. I was right about those 2 screws mounting it to laser not being enough to keep it square. I also shortened the end of it by 5mm as it was hitting a 2x4 I had under it.
Here is closeup of the shot thru the tape. Looks like the laser might be a little out of focus, but is about 5mm higher that surface I focused on.
Think I have printed my final version of this air assist bracket. On the latest version I added corner stops for the laser to make sure it was squared up & changed the bottom opening from 3mm to 4mm diameter.
