I have searched and read and watched an ungodly amount of media in regards to the aiming of CO2 lasers. I believe I am heading down the right path.
I fear I have a twisted gantry or frame causing low power cut through issues.
Why I believe this is that I can cut a materials card test card out of 3 mm baltic birch in the upper right section of the bed and get items the results I’m expecting.
I can cut super tight lines (1 mm wide left after cut) through with complete drop out and no pieces hanging on, just lift the sheet and everything is left on the bed.
But only on 3/4’s of the bed. My front right corner will not cut through at the same settings as the top left corner.
I have spent close to four days @ 6-8 hours learning and adjusting and reading and adjusting and watching and adjusting and nothing seems to cure it except raising power or lowering speed, of course this leaves me with differing results from one corner to the other on the diagonal.
When performing the alignment I can get what I would call 95% perfect overlay on my marks on the 2 -3 mirror setup when traversing the x axis from left to right at the rear of the bed and also at the fore of the bed.
When I check the marking at rear left to front right the are only 75 to 80% overlay.
Photos, hopefully, below.
The wisdom of the giants would be appreciated so I can stand on your shoulders…
Good morning, until the “giants” have come up from their beds, I will prepare a little for them.
First, make sure your tube is OK, with the appearance of the picture of your M1 it can’t be judged, try with less power and or short pulse time to get a light brown marking of your laser beam.
Without wanting to make you sad, but M2 is not in center. I know it can be hard to hit the middle perfect some time and that some giants (?) think it’s not the most important thing, just near and far hit each other … I want them in center on M2 and that of course, also applies to M1 and M3.
You also need to remember to check if your nozzle is perpendicular, there are many who forget this step.
Last, but you’ve probably already checked it is whether your machine bed has the same distance from the nozzle over the entire machine bed.
Agreed, except for m3. It may not be centered on m3 as head Z movement determine X axes alignment down the tube and Y adjustment (from m2) determines Y axes position of the beam in the tube. If it doesn’t go down the center of the tube, the beam will not be vertical after it comes out of the lens.
Lighten up on the burn time so we can see the power across the spot.
You may not have adjustments on the head or m2, so you’ll have to do the best you can.
The head that came with my machine, as you can see, the hole isn’t centered over it’s own mirror or the down tube where the lens is mounted.
Sometimes you can correct the 4th corner anomaly by adjusting m1. It’s very touchy and you don’t want to disturb the alignment with the other mirrors, so a very, very, very slight adjustment is all that’s required.
@bernd.dk - Definitely agree that my points are not centered but after reviewing all the various guides it wasn’t totally clear whether that was a necessity or a nice to have. Will now try to center everything as well.
I should have assumed otherwise but the drive to make things versus fiddle with trying to achieve perfection got the better of me.
@jkwilborn - Thanks, I believe I read through one of your other posts to another poor soul that ended up finding the issue to be that the laser head itself was cattywampus on the Y axis.
I sincerely appreciate the assistance and will be puttering away at it again today and should be able to update in a while.
When we suggest things, we have to make assumptions and you know how that goes.
With any engraver like these, they need to be square in all 3 dimensions. Since most of the rails or internal frame is built using jigs to ensure they are square, it’s unlikely that the frame is bent, although it happens. How I can’t imagine.
When it comes to the head there is lots of ways it can be off, but we usually consider other adjustments first. Head being square should have been brought up in one or more of the videos you’ve watched.
Also as recommended by another and it makes sense to me, request was to check and set alignment on LH front and Rear and then see is RH front and rear align.
Results were that LH F and R can be aligned and that makes RH Front and Rear align but LH and RH are different by, you guessed it, 3mm.
I’m a little surprised that you can get the relatively nice result that you see in the last picture (if I understand it correctly). It shouldn’t be possible with a 3mm deviation from the squareness.
I would still like to see a clearer picture of your laser beam on M1, not as a burned-out black spot but as a brown round filled circle.
It will be interesting what OMT servis can do about your problem.
I got the majority of my issues resolved. I’m a bit slow sometimes and once I understood what Omtech was asking me to do to adjust the gantry, I started making progress. I now have the gantry squared. This allowed me to correctly align my mirrors.
It is working ok now, I’m still testing theories but it seems that the laser is low on power compared to other test cards from 40 w units I’ve seen. I then found that my focal lens was odd in appearance and there’s some material I can’t clean off or the coating was/is damaged. New one is on its way.
It also appears, maybe due to the lens issue, that I need to put the focal distance a mil closer than the gauge that Omtech provided. The bed itself is to low as well as when the nozzle is set to the “proper” depth, the tube is just barely in the body anymore and a whisper of a touch will cause it to move. The bed has been shimmed to remove this issue.
I like to consider myself slightly above a nincompoop, but either that’s not as true as I think or I might have gotten a machine built on the friday before the long weekend by the new guy.
Anyways, Thanks again!
And I might even update further if it doesn’t shine any more light on my inadequacies, HAHA!
Happy New Year, and I wish you a speedy recovery.
Monday machine… - it’s always a risk, no matter where the machines come from.
When your tube is now square and that also applies to your machine bed and your nozzle, you should be able to “synchronize” the optics, as long as you don’t compromise on the result.
Good luck, we’re excited about the final result.
Well it looks like I’m getting pretty well sorted on the machine. Thanks again for all your help.
I feel like I’m really getting a handle on lightburn too.
Here’s what I designed and made from scratch, other than the graphics which the evil AI helped me with.
Top plate had about ten to fourteen layers depending on whether you count the masking layers.
I am happy for your feedback. There is always a point to overcome, then progress will come and it is very important not to give up.
In addition, you should not compromise on quality that could be avoided. There are only 2 states of a laser, in focus or not in focus
As I said before, this is a process that requires perseverance and a willingness to learn, then such fine results will come as your very fine box, congratulations.
