Colab COVID-19 Update


CoLab is (and has been for a while) available for single-user access and small groups from the same household for machine use by appointment only. Go to the Schedule page and request access as usual if you want to use the laser on these terms, or email if you have questions about the policy.

Indoor classes, including our laser safety classes, are still considered unsafe. Classes will resume as soon as conditions permit.

Avoid Fast Z motion

Yesterday I took the laser partway apart, looking for reasons why the Z-axis table keeps getting out of alignment. I think I know more than I did before, but I still don’t fully understand what’s happening. The problem seems to be in the acme threaded nut that rides up and down on the right rear acme threaded rod. You can hear the mechanism going “clunk clunk clunk” when that corner is slipping out of alignment.

This mainly seems to happen when the table is going UP in the FAST Z mode. That makes sense, because that’s when the mechanism is working hardest to lift the weight on the table, the honeycomb mesh, and your workpiece.

So, I am asking all laser users to please avoid using FAST Z motion until I’m able to isolate and fix the problem. It may take you a few extra seconds to focus using SLOW Z only, but it will help keep the table aligned and the laser working well. Thanks for your cooperation.

Update: problem has been fixed. You may use FAST Z motion normally unless you encounter that “clunk clunk clunk” sound again.

You Must Stay In The Room

I’ve heard that some users have been leaving the room unattended while the laser is running. This is NOT PERMITTED. No matter how safe you think the job is, Colaser safety policy requires you to remain in the room whenever the laser is running. If you are forced to leave the room for any reason, you must pause or cancel the job before you do.

If you feel unable to comply with this safety policy, please don’t use the laser.

Log Books Scanned

You may have noticed that Volume 2 of the paper log book has been losing its pages. My mistake for buying a notebook with tear-out pages! I’ve gathered up all the loose pages and sorted them into chronological order as best I could, and scanned both volumes into PDF files. Those files are now available for reference here in the Download section of the web site.

There is a third paper volume (hardcover, with pages that don’t tear out) in the laser room now. Please continue to log your work in the paper log book.

Red Dot laser fixed

The red dot spotting laser is working again, as of Thursday, October 5.

Sorry it took so long. The first attempt to order a replacement beam combiner got lost in the international mail. The second attempt succeeded, but the part arrived right before a busy couple of weeks for me. Then when I installed it, I discovered the red laser itself was damaged, so I had to wait for the replacement laser to come in.

Red dot laser (still) not working

On June 23, I had to remove the beam combiner that routes the red dot spotting laser through the same optics as the cutting laser, because the cumulative damage had pretty much destroyed it. Until the beam combiner is replaced, there will be no red dot to help you see where the laser will hit your material. I have ordered a new beam combiner, and a spare.

Update (August 4): In order to get a reasonable price on this specialized optical beam combiner, I ordered direct from a supplier in China. They quote a usual shipping time of 12-20 days. It has now been 41 days. Overdue, but I can’t open a dispute until 60 days have passed. If the slow boat doesn’t eventually arrive, I’ll have to re-order.

Until then, I hope you’re not having too much trouble using the laser without the red dot.

Power Back To Normal?

Today I went in to try and diagnose the problem with reduced power. Well, the problem is gone, but I didn’t do anything to fix it.

My hopeful theory was that the surge suppressors inside the high voltage power supply were starting to fail again. That’d be a cheap and easy repair. I opened up the high voltage power supply and found no visible damage to the surge suppressors, and they tested good with a multimeter (now in the toolbox for future use).

The power faded out during a class session, where we were running small jobs with longish pauses in between. It was a warm day, but far from the warmest we’ve had to deal with this year. Today I tried running several longish jobs at high power to stress the system, but couldn’t get it to misbehave.

Terry ran some quarter-inch acrylic cuts last night and also got normal performance (60 speed and 100 power to cut through).

So, I don’t know what was wrong, or whether it will be wrong again anytime soon.

Reduced Power Output

Toward the end of class yesterday we noted that the laser output power wasn’t up to par. Material that can usually be cut at 20% power was requiring 70%. Alignment test pulses were weaker than usual, even before passing through any optics.

That leaves the laser tube itself and the electronics. I’m hoping this is the same problem we had before, which turned out to be failing surge suppressors inside the high voltage power supply. If so, that’s a cheap and easy fix. If not, we may have an expensive repair to do.

In the meantime, as far as I know it’s OK to use the laser by just cranking up the power settings (or reducing speed). Be aware, though, that it’s likely to get worse or fail entirely.