Big Laser Problems

Something is definitely wrong with the big laser… There was a note on it when I arrived that it was skipping or had issues with vertical movement, plus when I tried it I noticed that the laser power seems greatly reduced and seems to get worse over time…

Can someone please take a look into it?

It appears that there are two problems with the big laser:

Low/decreasing power

Sean and I were at the Hive this afternoon and he showed me how the power level decreases as a cut is made. The cut barely makes it through thin wood and then as the cut continues it gets lighter and lighter.

After Sean left I tried to look into the laser for anything obviously wrong. The first thing I noticed was that the chiller was almost out of water. I added at least five of the pyrex measuring cups of tap water until it read full on the side sight gauge.

I turned on the laser and placed a small piece of wood under the optics and pressed the “laser” button. It did punch through the wood but the current spiked beyond 30ma. (On the small yellow sticker it mentions that the laser should not draw more than 27mA) I decreased the power level down to 50/50% and it hovered around 20mA.

I’m thinking the coolant water should not be generic tap water so we should drain it and fill it with distilled water.

Skipping/jerking while moving.

When Chris was working with it yesterday it lurched periodically when traversing forward or away from the front (Y?). You could feel the whole frame jerk a bit. I was thinking the belt was skipping but we should do some more troubleshooting. It seemed to do it while traversing (not cutting). After the “thump” it would continue to cut but everything was offset by a few millimeters.

I opened the back panel and looked at the drive but nothing seemed out of place. The drive belt was not loose or damaged.

I left the note Chris wrote about the skipping.

Could someone more familiar with the laser dig into the skipping problem and maybe do a test cut to see if the laser needs alignment or see if the tube is dying/dead? I’m thinking we could run with the back door open and no laser beam (while wearing the laser safety glasses) and see if we can identify the skipping.

I also checked out the baby laser and the coolant bucket was almost empty. I cleaned it out and filled it with tap water about 80%. I turned on the power strip and the water seemed to be flowing. I did a quick laser pulse and it did punch through the thin wood.

I hope to be at the meeting Tuesday night.

I was able to go to the Hive Monday after work and we tested the big laser out.
It seems to be cutting the material test piece OK.
I think the low coolant in the chiller was causing the laser tube to overheat. (Which is not a good thing).
The system does seem to be drawing more mA then the sticker says is OK. Does anyone have experience on what is “normal”?

We didn’t have time to do the traverse testing for the skipping/jumping before I left.
I think Tim was playing with it when I had to leave (any update?).

I should be able to come down before the meeting so we can dig a bit more into things.
Please be careful if you do any work with the guards open. Wear the laser goggles just in case. :sunglasses:

In regards to jumping and skipping, I tried multiple times last night to see if I could get it to happen again (I observed it happen once) but everything ran fine for my tests. I was helping someone out with laser engraving for a few hours and everything ran smooth.

Today Sven/Sean had the same skipping problem.

It seems to occur when the armature was down near the front of the laser bed approximately under the D in the danger warning sign on the top of the lid.

Brett P just showed up and he reported that it may be related to speed.


Interesting, maybe we should keep a log sheet near the laser to record when it skips. It could be due to location or speed. Important thing is to duplicate it so we can troubleshoot.

Stay safe