I don’t have a TFT, so I don’t know if/how to edit the g-code attached to the buttons. I’m not sure of your software pipeline, but since you mentioned Repetier-Host, you can attach code to the five custom buttons as an alternate to using the TFT to turn the laser on/off. I don’t have a laser yet. Keep saying I’ll get one, but other projects get in the way. But I’ve following laser information on the forum to prepare. So far no one as indicated a benefit of one method (fan control) vs another (laser pin) for controlling the laser, so if you have it working…
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@DougJoseph is exploring the possibility to add a diode laser to an SKR Pro 1.2.
His future tutorial could be your solution, I’m waiting for it as well 
A lot has changed since this two-year-old post. For many laser modules, it is plug-and-play to get them up and running. The latest V1 maintained Marlin firmware has laser support enabled by default. If you know what laser module you will be using, there are several people on this forum that are willing to help you walk through the process.
I purchased my laser module in September of 2021, and have hundreds of hours of use.
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Which laser do you use? Do you have the concrete model?
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And the one I’m getting is from the same place, but costs less, and is not as powerful as that one. Here’s the link:
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In terms of laser modules, I have a 5.5W Genmitsu laser on my CoreXY laser engraver and I really like it for engraving, but it’s not a good cutter.
I have a NEJE A40640 that I had set up for the LR3, which I plan to replace with an E40 module, maybe make another CoreXY machine for the A40640. I’ll need to make some edits for the larger heat sink, but it should make a nice all-purpose laser.
Neither is running on an SKR Pro though, so I can’t help much there
When i had my laser connected to my lr2 using the original skr pro 1.2 board i used this one: Link to post
Thats for a neje module to be installed with the skr pro (i didn’t used the key) you could even use it directly with light burn (wired to usb obviously)
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Of Late I hear good things about XTool’s laser modules (between $500 and $1,500) being actually worth the $$. My Diode Laser is definitely less powerful than it was back in 2020…
Lol, a cheap k40 can be modded and still be under that price.
Do you clean your diode regularly, just clean the lens regularly
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Would you expound on differences between A40640 and E40 and why you plan to switch?
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It would be awesome if you could pair it with air assist for cleaner etching, deeper cuts, and to save your lens/extend the life span of the laser, like Ryan recommends at Main - V1 Engineering Documentation
I already have one that I’ve not ever used yet. This could be a good initiation for it.
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So far as I can see, the E40 just has a metal provision for air assist. It also seems to be a bit longer focal length, which is probably the biggest advantage. I’ve melted a few plastic air assist pieces now because of inadequate air flow when a hose gets pinched. I have some ideas for the A40640 that I want to try.
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Cool, thanks for the explanation!
Are you sure? From my research, the E40 has a much shorter focal length resulting in a very minimal distance between the module and the stock. You can adjust the focus on the A409640 for a short focal distance, but most of them come with the lens screwed in which gives about 20mm of distance between the cowling and the stock. The air assist solution may take part of this distance depending on the solution.
The E40 is a fixed focus, they say 5mm from the heat sink. The A40640 is variable focus, they say 30-70mm from the lens but 30mm seems to still be inside the heat sink, and I’ve never managed to get an acceptable focus where there is more than a couple of mm from the heat sink. The E40 laser looks like it is higher up in the mechanism as well, as the heat sink is taller. This implies a tighter cone from the focus more suitable to cutting. Also at longer focal lengths, the A40640 starts to distort the beam pattern and you don’t get as tight a spot. (NEJE recommends focusing 2-3mm from the heat sink.)
Am I sure? Well, no. These are my impressions from the 2 modules side-by-side.
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I’ve always used my A40640 with the lens screwed all the way down (longest focal distance). With the lens in this position, I’ve tried a number of focus tests in order to figure out the distance. For engraving, my spacer (used from the heat sink) is 19.8mm. For cutting, my spacer is 18.2mm (places the focus point in the material). My kerf adjustment for boxes is 0.09mm, so the kerf is about twice that number at 0.18mm. My resolution for engraving is about 300lpi. I get banding if I go in tighter.
From the videos I’ve watched (like this one) , it looks like the E40 is much closer than 20mm. Visually it looks like the focus distance from the heat sink is about 5mm, and the presenter of the above video complains about the close focus distance not leaving any room for hold downs.
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Seems like I may need to play with the focus on mine more.
Like I said, NEJE recommends setting the focus 2-3mm from the heat sink, and that’s where mine is currently. I see the laser spot getting larger at the further distance with it (I thought) appropriately focused, and notably less square.
Honestly I use my 5.5W Genmitsu laser a lot more than the NEJE modules, because it’s permanently emplaced in a machine, and I don’t have to change anything out. The A40640 will probably get its own machine, and the E40 will take the LR3 spot.
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I purchased three Neje A40640’s (pre-E40)… and designed an air-assist nozzle that extends 15mm below the bottom edge of the housing. All three of my Neje A40640, as delivered and never adjusted, focused 20mm - 22mm from the bottom edge… leaving 5mm - 7mm from the nozzle tip to material surface. Here, I’m engraving and cutting 3mm plywood in one pass…
– David
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