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View Full Version : ULS 25 ER Y-axis reproducibilty problem



Kay Bengtson
07-20-2010, 3:37 PM
I am having trouble with our ULS 25ER laser cutter. I have only been operating it for a month.

Mostly the laser is operating very well except for y axis reproducibility. I cut parts that have tabs in them so they don't fall out of the balsa wood sheet. When the laser returns to a gap in a horizontal line after cutting elsewhere on the sheet, it sometimes shoots high or low by about 1/64" to 1/32" making the cutting lines look misaligned. It does it reproducibly in that if I cut the part over and over again, the misalignment is the same. I am cutting at 1.2% speed but the effect happens at every speed by just about the same degree.

If I move the image to another place in the cutting field, the result is the same.

I optimize in CAD every part on every sheet now to try to avoid this problem. I have checked the rubber bearings to see that they don't slip and adjusted them according to the manual. I was told by the fellow I bought it from that this machine was totally refurbished just a few months ago with all new bearings and belts.

The carriage isn't twisted as it bottoms on both sides with the frame. Also, when I first turn on the machine sometimes the x position gets messed up and the laser cuts everything shifted left by up to two inches. Sometimes less. If I turn off the power a few times or move the carriage about, it settles in and seems to know where the correct cutting area is.

Also, The carriage does seem to have more resistance to hand movement in the last six inches of the Y direction. If I move it back and forth, it loosens up.

How can I correct these issues? Will I need to call someone to come for a repair?

Many Thanks,
Kay

Terry Swift
07-20-2010, 3:59 PM
Kay,

Have you tried Universal Laser Support? Awesome bunch of people and they may have an easy answer for you.

I've used them a few times and they give good advice.

Kay Bengtson
07-20-2010, 4:03 PM
Terry,
Not ULS directly. I was given the impression that they do not support the ULS 25 series anymore. I am contacting local firms to see if they can help.

Kay

Scott Shepherd
07-20-2010, 4:14 PM
Kay, I'd call ULS directly. I'm not aware that they won't help trouble shoot on any older machines. I doubt that. It's free to call them, and if they can help, they will. They have all the manuals from the older machines, so I'm sure they can help troubleshoot it. They didn't stop making it and throw all their stuff away :) Give them a call, they will help.

There are many questions we'd need to know, like when was the last time the belts and bearings in the X and Y axis changed? When the machine doesn't come back to the same place, it's been my experience that it's a worn belt/bearing issue. I had that issue, replaced the belts and bearings, it went away.

However, I can't comment on the other startup issues you mention.

Give ULS a call. It's free, only takes a minute and you'll be on your way to getting it fixed. They can send parts and then walk you through fixing it yourself. It's not complicated.

Kay Bengtson
07-20-2010, 4:23 PM
Here is a photo of what is happening.

Kay

Kay Bengtson
07-20-2010, 4:26 PM
Kay, I'd call ULS directly. I'm not aware that they won't help trouble shoot on any older machines. I doubt that. It's free to call them, and if they can help, they will. They have all the manuals from the older machines, so I'm sure they can help troubleshoot it. They didn't stop making it and throw all their stuff away :) Give them a call, they will help.

There are many questions we'd need to know, like when was the last time the belts and bearings in the X and Y axis changed? When the machine doesn't come back to the same place, it's been my experience that it's a worn belt/bearing issue. I had that issue, replaced the belts and bearings, it went away.

However, I can't comment on the other startup issues you mention.

Give ULS a call. It's free, only takes a minute and you'll be on your way to getting it fixed. They can send parts and then walk you through fixing it yourself. It's not complicated.


Thanks, Scott. I was told that the belts and bearings were replaced just a few months ago. I was shown the invoice and the old parts that came out. The belts seem to be shiny and new too.

I will contact ULS.

Kay

Terry Swift
07-20-2010, 5:51 PM
Kay,

I have an older M300 and they have never questioned me about it being old or out-of-date. I've called numerous times with issues; as my local ULS Firm has it's hands full and it's hard to get in contact with them. If you bought it local - then they should be helping you, especially if they refurbished it.

ULS can and will help though.

Kay Bengtson
07-20-2010, 5:56 PM
Kay,

I have an older M300 and they have never questioned me about it being old or out-of-date. I've called numerous times with issues; as my local ULS Firm has it's hands full and it's hard to get in contact with them. If you bought it local - then they should be helping you, especially if they refurbished it.

ULS can and will help though.


I did buy it locally but not from ULS or a vendor. The person who did the work was not trained in repair but he did seem to understand the requirements.

Kay

Scott Shepherd
07-20-2010, 6:15 PM
To me, looks like it could be something simple. I've not seen that model, so I'm not sure how it's built, but first, I'd make triple sure that when the power is off, and you slide the y-axis all the way to the front of the machine, it hits the stops on both sides at the same time.

If that's correct, then to me, it looks like a belt tension issue. There's a specific tension that has to be on them and it might be too loose.

That's all just a guess.

ULS is free, even if you didn't buy it from them, so it's easy. You can just email them the photo and they'll respond as well.

Kay Bengtson
07-20-2010, 6:20 PM
To me, looks like it could be something simple. I've not seen that model, so I'm not sure how it's built, but first, I'd make triple sure that when the power is off, and you slide the y-axis all the way to the front of the machine, it hits the stops on both sides at the same time.

If that's correct, then to me, it looks like a belt tension issue. There's a specific tension that has to be on them and it might be too loose.

That's all just a guess.

ULS is free, even if you didn't buy it from them, so it's easy. You can just email them the photo and they'll respond as well.


I did contact ULS with the photo and they just responded saying that a tech should come and work on it. They think it could be the stepper motors or an idler or even the CPU.

The carriage does hit both sides when moved by hand.

As for belt tension, that could be an issue, I have adjusted it a little but it didn't affect the problem at all. The service manual that I have shows how to do that and I followed it.

Kay

Bruce Volden
07-20-2010, 8:52 PM
I agree with Scott-----it does seem totally like a mechanical issue. I have had "wierd" things happen that seem realted to file transfer, computer, laser failure,etc. But in the end it was always something simple and mechanical, my advice to you would be to keep "digging", this will allow you to become more intimate with your machine. And, as a side note, contact ULS and I'm sure they will help you. Things like this are ALWAYS a nuisance as they always happen at the most inopportune times and get us second guessing ourselves :eek: DON"T give up and please do report back to us as we all follow what's posted here.

Bruce

Kay Bengtson
07-20-2010, 9:13 PM
I agree with Scott-----it does seem totally like a mechanical issue. I have had "wierd" things happen that seem realted to file transfer, computer, laser failure,etc. But in the end it was always something simple and mechanical, my advice to you would be to keep "digging", this will allow you to become more intimate with your machine. And, as a side note, contact ULS and I'm sure they will help you. Things like this are ALWAYS a nuisance as they always happen at the most inopportune times and get us second guessing ourselves :eek: DON"T give up and please do report back to us as we all follow what's posted here.

Bruce

I have been through the service manual a lot and it is really not that difficult to understand. This afternoon I checked again and found that the tension on the right belt was loose, so loose that the tightening screw mechanism was loose. Sadly, though when I tightened it up so that the tension matched the left belt, the problem didn't go away. In fact, no change at all in the problem. :confused:

ULS service got back to me as I mentioned and they said the unit should be serviced. I have calls or emails into three different firms to see if any can come but so far none have responded. Since none are really local, this is probably going to be an expensive repair.

You are so right that these things happen at the worst times. I was really getting into cutting and cut quite a few kits when this happened. I feel like a friend is sick. :(

Kay

paul mott
07-21-2010, 3:01 AM
Hi Kay,

This is probably not much help to you because it is really the job for a technician but the problem looks to me like it could be caused by electrical noise. It appears that, as the laser fires (after a tab) a false step pulse is being generated thus moving that one axis.


It perhaps would not hurt to visually check all the wiring and especially the routing of the HT cable (careful with this as the HT will retain a charge for some time after the machine has been powered down) to make sure it is neat and tidy and looks like original (not bodged or tampered with).
Or perhaps get a local technician to check for you the tightness of all connectors and other electrical connections.



Paul.

Rodne Gold
07-21-2010, 4:35 AM
Looks to me as if a stepper motor is losing steps or stalling - could be the motor or the stepper motor drivers on the motherboard.
If you rotate the drawing 90 degrees, does it make the same error or does the error appear somewhere else?

Mike Ross
07-21-2010, 10:25 AM
Hi Kay,

I have the same machine. It is a dinosaur but still cuts :)

If you want to send me the file, I can cut it on my machine to see if the same thing is happening. If both machines make the same error, I would suspect the problem is in the file, not the machine.

My machine sometimes offsets by two inches as well, have not figured that one out yet, but am able to work around it by restarting as you do.

Shoot me an email at mike@nwplank.com if you want.

Mike Ross

Chris J Drew
07-21-2010, 11:15 AM
If there are grub-screws on any Y-axis drive pulleys make sure they are all tight.

Richard Coers
07-21-2010, 12:34 PM
You might also check that the bearings are not too tight on the extrusions. They can easily be preloaded too much. The stepper motors are really small and don't have much torque. I thought the head moved very easily on mine, but still had trouble. I added some bearing lube, everything moved easier, and no problems after that.

Kay Bengtson
07-21-2010, 12:51 PM
Robert Bosworth is helping me now and he suggested that I clean the proximity sensors with Qtip and alcohol. They were really dusty. I cleaned them and the initial losing the X position problem went away. I also sent him a batch of photos of the belts and bearings etc. Keeping my fingers crossed.

I'll check those bearings.

Kay

Kay Bengtson
07-21-2010, 2:42 PM
Well, things are not getting better. I tried a new cutting file and now the laser can't seem to hold vertical cuts anymore. Now they lean badly in different directions and the ability of the laser to return to a spot is also not working. This is odd too because, I have not adjusted anything on the x axis carriage. So what was happening on the Y axis now happens on the X axis too. Before at least the vertical cuts were always perfect.

Could this be the stepper motor controller/power supply failing?

Kay

Kay Bengtson
07-22-2010, 4:14 PM
Great news! My laser is up and running! It turned out to be a loose lens. There was a slight issue of belt tension which got better in the myriad of adjustments but during that time I must have bumped the lens and knocked it loose resulting in a huge problem. Robert Bosworth was so helpful and while I began to think the worst, he kept suggesting things to look at and bingo one worked! A huge thanks is owed to Robert!

Kay

Bruce Volden
07-22-2010, 7:03 PM
Ain't it great when you can fix something for virtually nothing?....'cept perhaps lotsa worries and frustrations. Glad to hear you're a go now! Always double, triple or more the mechanical aspects of the machine until you're certain that it "can't be at my end". Good for you!

Bruce

Kay Bengtson
07-22-2010, 7:32 PM
Ain't it great when you can fix something for virtually nothing?....'cept perhaps lotsa worries and frustrations. Glad to hear you're a go now! Always double, triple or more the mechanical aspects of the machine until you're certain that it "can't be at my end". Good for you!

Bruce
It was a roller coaster ride for sure. One minute I was expecting to have a $2000 + repair bill then the next it was fixed. I can imagine what I would have felt like if the repair person came and found a loose lens for the $400 minimum fee. So I am all the more grateful to Robert at usedlasers.com He will be on my list to buy from as I am sure I will eventually get a second machine.


And as it was as you said, the process taught me even more about the inner workings of this really fine laser cutter.

Kay