So I encounter something new for me tonight when I started a laser job. It started out cutting fine and then things got interesting. I have a Monport Reno Pro 45w co2 laser. I’ve had it for about 6 months. It’s been working great until today.
I ran the laser for about an hour last night. Worked great as it always does. Tonight, I flipped on the power and my Y axis limit switch didn’t trigger properly and the steppers skipped until I hit the power switch to stop it. Before I turned it back on I triggered the limit switch with my finger a few times. Flipped the power back on and then it homed properly without issue.
So, I put some material in the laser, fired up Lightburn and sent a job over to the machine. The job started in the upper right corner. I glanced at it to make sure it was burning and then sat back down to my computer to do other things while it was cutting. When finished, I saw that it cut a bunch of jagged lines.
I checked the belts. They seem fine. No missing teeth. Gears seem tight. Mirrors seem clean but I’m not sure how to take them apart and inspect. I took the mirror off at the top of the head and inspected. It’s clean. I’m not sure how to get to the nozzle mirror. The gantry seems tight. Nothing is wobbling. Not sure if it’s the tube. Don’t know how to check it anyway.
What do you think? In my 7 years of laser cutting this is a first for me.
I thought I would try pulsing the laser. It’s not burning the material. I stuck paper in front of the first mirror. It burned. Good! I papered the second mirror. It burned. Good! I papered the third mirror. It burned. Good! But nothing out of the nozzle. Perhaps there is an obstruction in there. I’m not sure how to get this thing apart. No instructions anywhere. Researching now.
I figured out how to get to the nozzle lens. The nut was definitely loose. Lens was clean. It pulses now. However, it’s very week. I can’t even cut a small hole. It’s like I lost power. I think I have tube problem. I’ll get with Monport and see if I can get a replacement…unless it’s something else.
Does the beam exit the air nozzle cleanly? The laser beam may be clipping the edge of the nozzle on exit.
Put a piece of tap over the air nozzle and pulse the laser. Usually I will put a small mirror the bed under the laser after the pulse and shine a light down through the laser head mirror to see how the hole in the tape is centered. Or just press the tape over the nozzle tightly so you get an imprint of the nozzle opening.
@NedMan The beam seems to exit the nozzle now. Perhaps it wasn’t before I removed it and tightened the the mirror retaining screw. I did put a piece of paper under the nozzle and pulsed. It cuts a clean hole but still at a loss of power.
I wish I could figure out how to get my mirrors out of the #1 and #2 holder.
if you are burning a hole in paper in front of the first mirror, in front of the 2nd mirror AND in front of the 3rd mirror(as it enters the laser head) then the problem is inside the head. either the mirror has cracked, pitted, burned, etc or the same happened to the lens or the beam isn’t coming out the cone if you have an air asssist cone on the bottom of your laser head.
@dougl I agree with that and I have already verified that. There are two set screws that keep the focal tube in place. Once I took that apart I saw that my focal lens retaining screw was loose. Way loose. I bet the air assist was moving that lens all over the place. I cleaned the lens and tightened it back down carefully and tried a test cut. I’ve lost power now. Maybe I don’t have the lens centered. I’ll check that this evening. I tried cutting a circle and the jagged lines are gone. I just can’t cut through the stock now. It’s barely etching.
@NedMan Roger that! I’m aware that the curved side goes upward but these 12mm lenses are tough to tell which side is curved, even when using a magnifying glass. Let me ask this…the lens is 12mm in diameter. The tube it sits in is 13mm in diameter. That means the lens doesn’t sit perfectly in the center. If the lens is pushed to one side, which is .5mm off center and it’s tightened down, does that affect the laser beam?
So, last night I had some time to fool around with things. I was able to get my lens tightened and centered in the tube the best I could and I can report that I no longer have jagged lines when cutting. But I have a new problem. I cannot cut through my material now. I get a nice crisp line when cutting but I have a major loss of power. I have been talking with Monport. They think my mirrors are misaligned. I’m going to try and realign everything tonight and see if that helps. If not then I suppose it’s the laser tube. Don’t now what else it could be.
Alright. Back in business! I was able to fix all of my problems. Issue #1 was a loose lens causing the jittery mess. Issue #2 was misaligned mirrors, mainly mirror #3. Monport helped me with the latter. I was sure it was a blown laser tube. Anyway, I’m cutting great again and couldn’t be more thrilled. I have stacks of acrylic to cut so hopefully no more issues.
As for the 12mm lens sliding around in the 13mm tube, I cut a small ring out of ABS today on my lathe. The lens fits inside of the ring. This keeps the lens dead center in the tube.
