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View Full Version : At my wits end



Brent Ramsay-Boyd
03-08-2017, 5:49 AM
I am hoping someone can help me, because my laser cutter is driving me insane.

I have spent days leveling the machine, aligning optics. I have replaced, my tube, my power supply and my optics, and still I cannot get my machine to work right.

My main problem at the moment. I am cutting pieces 830 x 350 out of 5mm clear cast perspex on my 1300 x 900 bed. I am cutting along the 900mm length to minimize the number of points the laser crosses the supports as it create flash points in the material. The laser seems to be cutting the top 70 - 80% of the piece fine, but the bottom 30% is not cutting all the way through. I am then having to re-cut that section and it is ruining my edges. Its for a display case.

I have checked the alignment at the 4 corners of the bed and all seems to be spot on. I have checked the distance from the cone to the bed and there is virtually no difference in distance across the whole bed. I am running the cut at 7mm per second, which is far slower than what I was getting when I first purchased the machine. (It worked ok for a few hours I would guess.)

I can run a 20 x 20mm test cut in that corner and it will cut through, then when I run the full piece it doesn't cut through.

I just don't know what more to do. At the moment, with the way I am feeling I just want to finish this job and get rid of the machine as soon as possible. I have not been able to run a single job on this machine without having to redo work since I got it three years ago.

Erik Goetheer
03-08-2017, 7:01 AM
So, if your laserbed is level and small pieces will cut through, it might be a problem with your laser (power supply). What does yout miniamp meter tell you when the machine is down to the final 30% of your workpiece? Is it at the same level as when you start your job?

And have you tried and see what happened when you start your job in that notorious corner?

Jerome Stanek
03-08-2017, 7:07 AM
Level isn't just that. measure from the tip of your cone to the table grid and see if all corners are the same. As for the flash back try a pin table or if you are cutting the same shape put a few standoffs under your material

Doug Fisher
03-08-2017, 9:56 PM
You haven't bee running your machine at 100% power have you? If so, you may have damaged your tube by overdriving it and thus it is now losing power.

You might want to watch Russ Sadler's Youtube videos at Sarbar Media to see how he tested and solved problems with different levels of power at different corners of the machine.

Kev Williams
03-08-2017, 10:50 PM
My Triumph started doing that awhile back, everything on the right end of the table wasn't getting the power the left end was. And I knew for a fact my optics were lined up, and the table was level- and by level, I mean level to the gantry, whereas my focus stub would fit anywhere from a perfect fit between the lens tube and the table, to a tiny bit it free play. And the thing arrived from China astoundingly perfect in the mirror alignment department.

But I found the problem- the perfect mirror alignment, wasn't.

In doing burn tests I noticed that lens mirror was getting hit just above center when closest the 2nd mirror (far left), and the farther right the head got, the farther up the lens mirror the burn got. I was thinking part of the beam may be hitting the top of the mirror hole. Left to right, the burn mark barely moved. A climbing beam meant I probably needed a full-on adjustment, starting at the tube and adjusting its mirror or even raising the tube... Didn't have time for that, so the next best thing was to adjust the second mirror so the beam started slightly below center on the 3rd mirror and ended up only slightly above center at the far right end of the table.

Thats what I did, and it's been engraving and cutting the same everywhere on the table ever since. So I'm pretty sure part of the beam was hitting the mirror hole.

another thing you might try just for fun- If you're using the nose cone, remove it and give it a test run. If your 'cold side' picks up, you're beam is hitting the cone due to misalignment-- I took my cone off the minute I got the machine...