I’m seriously debating retrofitting my K40 to use a 5w+ diode laser instead of a C02 tube. This is because the K40’s chassis, shoddy optics hardware and gantry just make mirror alignment a total nightmare. That, and I just don’t usually need the power that C02 provides. I’m cutting chipboard, paper and 3mm ply at a maximum. From what I’ve read so far, a sufficiently powerful diode can handle all of that fine with enough passes.
Question: Has anyone done this before? If you have, would you be willing to share your experiences, which laser module you ended up going with and why, etc?
@Bob_Buechler yes. I had a 3.8w diode attached to my CNC router. I was able to cut 3mm ply and acrylic with multiple passes with multiple Z increments. If you don’t then most likely the heat can deform or burn what you are trying to cut.
@Ariel_Yahni_UniKpty Good to know! and that makes sense. I imagine a motorized Z table is really the only way to handle that sanely, otherwise you’re adjusting Z by hand for almost every pass which would get prohibitive in a hurry.
You’ll be more limited in what you can cut as well - anything that diffuses or transmits visible light won’t be touched by a diode, so no cutting acrylic. I know that’s not on your list, but something to consider. You’ll find the power awfully underwhelming. Using a diode for cutting is painful compared to a CO2 laser - personal suggestion is to spend a little effort tightening and aligning the K40 - it’s really not that bad, and will be far superior to a diode for everything but image engraving.
If you’re still using the stock board you might consider a C3D Mini as well - much smoother, so easier on the alignment, and has software power control.
@LightBurn_Software I have spent hours trying to align the mirrors on my K40. Some people get lucky and theirs aren’t bad… not in my case though. I’ve torn my optics down to try and rig something easier, but it’s not going well. I’ve given up entirely on it. I’d pay someone to do it for me if I could find someone local to me. (Seattle area)
I think +Hakkan HP persson has a good guide on doing it. It takes a bit of time and patience, but I found mine similar to aligning the mirrors on my big laser, and worth it. If I was in the area I’d offer to help. I just think you’ll find a diode really limiting - I started with a 6.5w and gave up quickly. It burns a lot more than it cuts because it’s slow, and the heat builds up before material vaporizes. You get a lot of charred edges.
@LightBurn_Software Good to know. The fact that you started with a 6.5 and gave up on it gives me pause. I have Persson’s guide, and it’s great, but I don’t visualize angle adjustments well, despite hours of banging my head against it. I learn better through hands-on instruction… sadly, that’s not too available for in-home cutters yet, it seems.
I have a mirror height issue too, which is making it worse. The second stage mirror is on the stock K40 sheet metal bracket, and that is too flexible, and not perfectly square. So the mirror is too low I think, and I’m pretty sure it isn’t standing up straight either.
That can be bent up a little if necessary. Don’t be afraid to bang it up a little if needed. They don’t have to be super strong, because they carry very little weight.
I don’t think you are going to be happy with the power on a laser diode and its material sensitivity.
Is your alignment problems stability? i.e. why do you need continual adjustment?
I have thought about new mirror mounts and alignment gauges perhaps now is the time?
@donkjr I’ve never been able to get it aligned, if I’m honest. The K40 arrived with the second stage mirror just barely able to reflect to the laser head. They basically got just part of the beam to barely bounce off the very top corner edge of the mirror (most hitting the frame around the mirror) and that was enough to land a partial-strength beam on about 25% of the bed. When I added air assist, I needed perfect alignment to even make it through the laser head, and that’s when it all stopped.
What I need is a hands-on instructor to teach me how to align, because even with the great manuals I’ve found online, I could never solve the second stage problem. The hardware involved is just too cheap, fine tuned adjustments aren’t possible, especially if you need to fix a height issue.
I’ve raised and lowered the tube, raised and lowered the first mirror, raised and lowered the second mirror, and I could never get all three mirrors aligned (in all three dimensions).
It’s irritating because I know that if the chassis were square, and the hardware the mirrors are mounted to are level and at the same heights, then I wouldn’t even need the thumbscrews. And in my case, the fact that even with the thumbscrews, I still can’t manage a shot square enough to make it through my air assist nozzle is deeply frustrating.
After many hours of fighting with it, I eventually just gave up and let it sit in my garage.
I assume you mean this, when you say second stage? How badly off is yours? It’s not strong metal, so you could easily un-mount it, bend it as close to 90 as you can by hand / pliers, then re-mount and try aligning again.
I’ll toss you a DM to schedule something. Thank you.