Our 1390LC Laser Cutter
Can we leave the laser available for tours and demos weds night and do the calibration another time?
When the laser arrived, to my surprize the beam was perfectly aligned. The method described on the manual was not ideal though, it makes a lot of smoke and can get the mirrors dirty. I really like this guys technique and I think this is what we should do:
However, aligning mirrors should be the very last step of maintenance, after we have done all the other tasks. We should first do all the other choires like cleaning the bed to adjusting the belt and cleaning mirrors. Before attempting to align the beam, we should also make sure the nozzle is straight. I have noticed a couple of times, the nozzle has been sitting on an angle and the beam hits the edge of the nozzle which causes the beam to reflect and hit the material in a C shape.
Some important point to reiterate from the manual and the video: it is not important that the beam hit the center of the mirror – as long as the beam is aligned. This means hitting the mirror in the same location at the minimum and maximum location of each axis. We would also check that the beam is relatively round.
I will start a google document and share it with you guys, so hopefully we can write a complete maintenance manual in the next few days and build a solid maintenace team.
@arasbm I am interested in at least basic maintenance, as I see much laser in my future…
I added the hour meter to the machine tonight. It is inside the electronics compartment on the side.
I was talking to Crystal, and realized that I had not looked at the hour meter since I put it in there… 56.4 hours of lasering in the last 30 days.
Who’d have thunk it?
Maybe we clean lenses and check out the filters next monday?
I’d like to learn the laser maintenance as well
So, we have 65 hours on the laser since I installed the meter.
@Vaughn told me he cleaned the lenses in the last couple of days, so I got Jerid to swap out the furnace filter and vacuum out the filter enclosure.
I tried to fix the x-axis belt alignment issue, to no avail. It looks like the holes were drilled slightly off at the factory and it just took us a while to notice the wear on the belt. In order to compensate, we are going to have to make a mounting plate that gives us control of the pulley angle. Either that or resign ourselves to replacing the belt occasionally, and having spares in stock.
I confirmed that when you move the Z-axis, the laser dot still drifts down and to the left. Alignment is better than it was at its worst, but is still off. Also the laser, when in focus is not round at all:
I dropped the bed about an inch and a half between shots. The two hits should have nearly co-witnessed but the beam drifts as it moves down. Also, the close hit beam should have been perfectly circular. Initially I thought maybe the beam was hitting the inside of the lens tube. But this shot makes it clear that it is not hitting near the center of the mirror at all:
That circle is me rubbing my greasy thumb on the paper and outlining where the hole that goes into the lenses is. Documentation I’m seeing online indicates that we need to hit within 2mm of the center of that circle everywhere on the bed. As it is, we are just clipping the edge of the circle, losing some of our beam, and getting the strongest part of the beam to hit the edge of the lens, which is likely curving it off center.
About 8 minutes 20 seconds into this video is a pretty good description of how to systematically remove the error from your laser alignment.
Also, I’ve created a very simple form for logging laser cutter maintenance:
It just saves info to a spreadsheet in google drive for now. I’d like to capture how many hours before various things need doing so we can start to predict issues. I’ll eventually build it out into `a proper maintenance application with a database backend, but this will do for now. If you do work on the laser, or replace any bits, please use the form to make it easy to track. I’ll try to put it on the desktop on the laser-cutting machine.
I did some cutting yesterday afternoon. 3 things:
- it’s generally cutting more vertically than when I used it a few weeks ago, eg, my cuts didn’t have a slope to them.
- before I started, the bed was not nearly high enough, and the bed was bowed upwards, eg “concave”. It seems the back of the bed was caught on the frame, so I lowered it down and pulled the bed forward, at which point it moved freely, and came up high enough to focus properly.
- it looks like the laser is out of alignment when cutting on the forward right corner (towards the control panel) like the laser is diffracted inside the tube and cutting two lines. I noticed this on a few pieces. I’ll see if I can find a sample to get a picture of.
I also noticed today, the laser doesn’t look like it’s coming out of the center of the tube at all
I am concerned the laser is hitting the inner housing of the lens enclosure and may be damaging the part!
One thing to note: when the honey comb is taken out and replaced for cutting on the rails, the honey comb has to be properly aligned on the rails or it can catch under the blue surround! That may even be the cause of the bad being out of alignment with the gantry/laser.
I will be there on Thursday for the first aid workshop, after I will inspect the laser and report back.
I’m interested in learning as well. Happy to learn the procedures and document maintenance done in the log.
Watching this today. Will not attempt the procedure without the assistance of someone who has done it before.
@Vaughn The laser has not got nearly the power to damage the aluminum tube. Not by several orders of magnitude. I wish we had that problem, because then we’d be able to cut and engrave metal.
It’ll mark the anodized coating if it is in focus when it hits it though, which might tell us if we are hitting the edge of the tube after we exit the last lens.
Beam is about 8mm in diameter before it hits the last mirror so the energy concentration is considerably lower than it is after the lenses. It barely sets paper on fire on a full power pulse. If I could get a decent filter that gave me about 10% IR transmission, we could probably see interesting things by burning paper with the unfocused beam.
so @pierre and I did a quick inspection today after the workshop. The laser is out of alignment. It also not hitting in a round circle shape as you would expect. This may be due to damages mirror or lens, or hitting side of one of the mirrors on the way. We need to set a few hours aside and do a full inspection and realignment of the mirrors.
I do not think it is unsafe to continue to use the laser for now, however you may notice reduce cut quality.
Laser is down again. Tube is broken this time. As you can see here in glorious potato-vision (trying to get my phone to focus on the inner tube instead of reflections off the outer was not cool. Somebody needs to design a manual-focus cell-phone.
The metal terminal (Not sure if it is cathode or anode, but I suspect cathode, because it is serviced by a tiny-uninsulated black wire… the other end has high-voltage insulation) at the business end of the laser has broken off the inner glass tube (The spring noise that @Krankin heard) and there is now water in what was the sealed CO2 chamber.
My reading indicates that you get about 1000-2000 hours of cutting time out of such a tube, and I need to check the hour meter again, but I think it has put in over 300 hours in the last 4 months. So we likely just used it up. Next time we’ll hopefully have warning well before the tube hits end of life and have a replacement in hand when the time comes.
I’m shopping around for a replacement 120w CO2 laser tube now. We’ll fund-raise for it when we have a good idea of the shipped cost. It’ll likely take at least a week to get the new tube, so I was talking to @Grant-Fraser about rebuilding the chiller with easier water changes and better filtration while it is down. @Vaughn was bending my ear about setting up an interlock so you cannot fire the laser with the chiller offline too. Ideally such a system would measure flow and temperature of the supply-side water, rather than just “make sure it is turned on” so that it will throw an error and refuse to fire when the pump fails.
@pierre RIP laser tube. You served us well
We should have over 100$ credit with G-Weike toward the purchase of a new laser tube. I strongly recommend going with the manufacturer because so far they have given us stuff that works really well for very cheap and their support has been decent too. @kile was last in touch with them over the firstname.lastname@example.org email before I hand over the email to makerspace. Please look at last conversation in there with G-Weike about ordering a laser tube.
The danger with ordering a cheap tube from some random supplier is that we have no assurance that it was not sitting on a shelf for the last 5 years. The laser tubes have limitted shelf life and they would fail much faster if they have been stored for too long. At least G-Weike seems interested in us referring them to other potential customers, so chances are they will act in our best interest.
Regarding the flow sensor, there is a flow sensor in line with the water tube. I do not know how it works and if it does work, but I would look at that first before implementing additional security for monitoring water flow. It might be working perfectly fine.
Good luck with finding a new tube. I will wait for someone to start a fundraising thread, but I will chip in 100$ toward a new tube, whichever you decide on.
The offer to info was $100 credit IF the guy I talked to about our laser ended up buying a laser from them. I am not sure if he did or not, but either way I agree with @arasbm, the manufacturer is probably the way to go. From the sounds of it our tube performed to (or above) spec in terms of hours. It will be nice to track the hours on the new one from the start.
I’ll chip in $100.
Does G-Weike carry the rotary tool for the laser? If so, how much is that?
The Clay Space grant does include that tool as a line item. We need to have the capability in place for the Clay Space programme launch Sept 1.
@pierre mentioned he could make one, but with all he has to do I think researching an off the shelf model is a good idea.