Hello,
My K40 already has a red dot guidance system that utilizes a drag chain and no room for adding air assist to this existing chain. See photos of my K40 as explanation. Would appreciate any suggestions you have .
Thanks !
Russa4920
How about a wider drag train? You dont have many options.
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Do you mean to purchase a wider drag chain and reinstall all in this new unit? Thought about that but chains I have seen are all about same internal space.
Looks like plenty of room in there for some 4mm tubing. What size were you planning to use ? Your laser dot wiring looks VERY substantial and maybe could be reduced but if the grey is for the dot laser, what is the red for ?
Alternatively, if you use the stiff blue nylon tubing, I would have thought an S shape would drape across the machine supported by crossing the existing drag chain and tapering into the lens assembly near the dot laser.
Well the existing drag chain is less than 10 mm wide and the dot guidance wiring which has a 5/16" protective poly sleeve over the wiring makes it very tight. Considered upsizing and replacing existing drag chain but then I would have to change a laser head bracket which supports the drag chain on the gantry rail. I planned to run 6 mm blue poly but it’s much stiffer than I predicted so I will most likely be switching to a more flexible clear poly at least through an additional drag chain to be installed.
So this is a work in progress but I was able to modify purchased drag chain. …see photo.
Thanks for feedback.
Russa4920
Very simple!! I like it. Think I will do the same. Thanks much Doug!!
Have a great evening.
Russa4920
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By 5/16" do you mean that spiral wrap? It doesn’t look like that goes clear through the chain, just an inch into it. I’d probably cut it a little short so it stops outside the chain then add a hose alongside the wire in the existing chain. You don’t need a very large diameter.
Good idea Mark and your correct. Actually looking at two options now :
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I can fit a 4mm OD flexible poly line into the existing drag chain but would be a little more pressure drop and then less flow. My injection nozzle allows for flow adjustment but this less flow to the nozzle may limit my ability to control flow . The nozzle manufacturer says it’s made for adjustable flow specifically to improve engraving which is what I do mostly.
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Run 6 mm flexible poly line in my additional drag chain shown in photo . This would give me more flow because it’s slightly less pressure drop, realizing that it may only be ounces more .
Your say you don’t need much flow so maybe option #1 may work and each much cleaner , less use of cabinet space I may run both and then test each during my next engrave run. If option #2 works better, I may option to replace the existing drag chain with a slightly wider size which allows the 6 mm tubing run. This would require me to disconnect the red guidance line from control board and rerun in new drag chain along with 6 mm tubing. I eventually plan to replace my control motherboard with a Lightburn capable one so I would do this at same time.
Overall it’s nice to be able to consider all available modifications on the K40. Thanks for feedback!
Russa4920
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The arrangement I’ve put in my monocle laser cutter that I haven’t yet finished or fired up (sigh) is like @dougl’s and I used silicone tube in the drag chain, and then I just stretched the end of it over a piece of vinyl tube right at the laser head. Because my lens can move up and down a few inches (Cloudray C head), I spiraled the vinyl around the laser head so that it stays out of the way through the full range of travel.
Ignore the drag chain location in this picture; I hadn’t worked out yet how to route it when I took the picture. But this shows what I did at the laser head, both fully extended:
and fully retracted:
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Thanks Michael. Helps me understand tubing material options. I ended up running vinyl combined with blue poly tube( more Ridgid) but ordered some 6 mm silicone tubing that I plan to use in future changes.
I really like making K40 modifications and in the process of planning my upgrades , I ran into some laser build kits and thought this may be my future goal after I gain experience with my K40. Can you turn me into some forum links that show me laser build options?
Thank you
Russa4920
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I don’t use a drag chain for the air assist. I actually don’t have a drag chain on the X axes…
This tubing is super flexible. The air line is held to the Y gantry up to it’s center and the tube just flexes as the machine runs…
It’s been this way for quite a while … no issues…
What I’m suggesting is to run the air line external of the drag chain and let the hose follow the head along, similar to mine…
Here is a video link, you can see how it operates on my machine…
Good luck
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Got it now. Thanks for the suggestion. I may end up here.
Russa4920
I think you’re already here… 
Let us know what you worked out.
Good luck
Missed your video link the first time I viewed your email Jack. Looks like most folks are using laser heads that combine the air injection nozzle rather than separate lines like mine . Am I correct here and why is this possibly better? In addition to air line routing options, I’m considering changing out my laser head to one that includes an air nozzle .
Thanks for all feedback folks!
Russa4920
Air assist through the nozzle helps keep the lens clean, blows the char away from the laser path no matter which way the head is moving, and makes the cut edges more even.
https://makerfreedom.com/air-assist-for-beginners-laser-cutting/
Thoughts on the best method to inject air ? Combined laser head /air assist nozzle or separate nozzle? The attached article recommends a separate nozzle like I currently have but I’ve also read articles that say the opposite, recommending a combined nozzle as long as you have a strong enough air compressor ie 800 L/min or better?
Would appreciate your feedback as I see most who have commented to my original post on air line routing have the laser head with air line nozzle combined.
Thanks for your time
Russa4920
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Thanks Michael! Thought this was the case and like I said read some recent articles that stated this. The separate nozzle I have is nice in that it allows me to change the air path but not sure of the real value added here and like you said it doesn’t protect the lens.
Russa4920
I can’t see yours exactly, but it looks like it just blows across the surface.
The main reason for air assist is lens protection. The other is for cutting.
One for cutting (longer lenses, longer nozzle), one for engraving (shorter lenses, shorter nozzle). First photo on left, the drag chain is still on the machine.
Good luck