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    Default Re: Rebuild log Universal Laser Systems 25PS

    Hi, I've found this thread very interesting. I have a very similar laser cutter, works well, except for either the laser itself, the power supply or both. Where would you suggest I begin getting it up to full power again? I've seen the laser intensity vary in the middle of a cut, which makes me think power supply, but I don't have much experience with laser tubes at all.



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    Default Re: Rebuild log Universal Laser Systems 25PS

    Is your laser air or water cooled? (since you said it was similar want to make sure it has a air cooled RF laser on it)

    If so have you checked the fans / airflow?

    Since the laser is working but the power changes mid cut it sounds like the tube is heating up and dropping it's output.

    Another easy thing to check that would cause similar issues is the mirrors. As the head travels along the mirrors will shift slightly and the beam may be riding in and out of a bad spot on the mirror.

    Both of those things are easy to check so would be my first suggestion. If those both look good (or if your laser is water cooled) post back with the brand laser so I can do some searching on what setup it uses. (some the laser and tube are integrated others they are separate and even in the separate category there is LV and HV supplies. )



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    Default Re: Rebuild log Universal Laser Systems 25PS

    My ULS25PS was recently performing similar to what you are experiencing. It was manufactured in 1995, and was running on the original RF laser. Just the fact that it was still engraving after almost 20 years on the original laser was a miracle of its own. I changed it out to a liquid cooled glass tube this past year and it has been working great since. So, to this point of interest, what is the history of the Laser in your machine? If it is the original tube of similar age, it is time for replacement. If not, we'll talk more...



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    Default Re: Rebuild log Universal Laser Systems 25PS

    Yea the RF tubes are great for longevity and are regularly re-gassed and put back in service. Downside is they are 10x the cost of a HVDC (exposed glass) tubes new. My setup came without the laser head so have to start from scratch here. Wish I could find a good deal on a RF head for it but more than likely will go HVDC just due to cost and the fact it will be used infrequently (compared to what a business would do)



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    Default Re: Rebuild log Universal Laser Systems 25PS

    Quote Originally Posted by wireb View Post
    Is your laser air or water cooled? (since you said it was similar want to make sure it has a air cooled RF laser on it)

    If so have you checked the fans / airflow?

    Since the laser is working but the power changes mid cut it sounds like the tube is heating up and dropping it's output.

    Another easy thing to check that would cause similar issues is the mirrors. As the head travels along the mirrors will shift slightly and the beam may be riding in and out of a bad spot on the mirror.

    Both of those things are easy to check so would be my first suggestion. If those both look good (or if your laser is water cooled) post back with the brand laser so I can do some searching on what setup it uses. (some the laser and tube are integrated others they are separate and even in the separate category there is LV and HV supplies. )
    Air cooled, fans work, airflow is good. I'm sure the mirrors and lenses aren't in great shape either. I haven't yet had a chance to open it up and get way into it. I'm fairly sure it is all original parts

    Quote Originally Posted by cgerber
    My ULS25PS was recently performing similar to what you are experiencing. It was manufactured in 1995, and was running on the original RF laser. Just the fact that it was still engraving after almost 20 years on the original laser was a miracle of its own. I changed it out to a liquid cooled glass tube this past year and it has been working great since. So, to this point of interest, what is the history of the Laser in your machine? If it is the original tube of similar age, it is time for replacement. If not, we'll talk more...
    As far as I know, it is all original. I'm curious about your tube though, how difficult was it to change? What all is involved? How much is the cost? X and Y work perfectly, It seems like a huge waste to let the machine die just because of the laser itself. I want to revive this, make it better than it was before. Any information would be greatly appreciated. Thanks.



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    Default Re: Rebuild log Universal Laser Systems 25PS

    The lenses and mirrors you want to look at are the "flying" one on the moving arms of the machine. Just take a flashlight and look at them. If there are spots and pitting they are bad. If they look like a clean mirror maybe with a yellow hue then all is well. The other part to check is the final focus lens where the beam exits the flying arm just before cutting the work piece. Again should be clear with maybe a yellow hue any pits or spots = bad.

    On the ULS 25PS replacing the original laser is a matter of removing a cover and 4 screws to remove the head. When putting the new one in you need to realign it but not too bad. They are VERY expensive to replace since it is RF tube and the driver electronics are included in it. They CAN be refilled / rebuilt for much less and typically work almost as good as new once done.



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    Default Re: Rebuild log Universal Laser Systems 25PS

    Quote Originally Posted by wireb View Post
    The lenses and mirrors you want to look at are the "flying" one on the moving arms of the machine. Just take a flashlight and look at them. If there are spots and pitting they are bad. If they look like a clean mirror maybe with a yellow hue then all is well. The other part to check is the final focus lens where the beam exits the flying arm just before cutting the work piece. Again should be clear with maybe a yellow hue any pits or spots = bad.

    On the ULS 25PS replacing the original laser is a matter of removing a cover and 4 screws to remove the head. When putting the new one in you need to realign it but not too bad. They are VERY expensive to replace since it is RF tube and the driver electronics are included in it. They CAN be refilled / rebuilt for much less and typically work almost as good as new once done.
    Would it be worth it to try to fix the tube? Should I start with the lens and mirror? Is Cgerber's method of replacing it with a liquid cooled tube easier/better/cheaper? Sorry for the flood of questions, this is my first foray into laser stuff. I know this could be an awesome machine with a bit of repair. I'll definitely give the lens(es) and mirror(s) a check next time I'm at the space.



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    Default Re: Rebuild log Universal Laser Systems 25PS

    In my case with my ULS25PS, I chose not to fix the tube, for several reasons. But, several decisions hinge upon one another.

    The old ULS electronic controls do not have the signal or power supply for a glass tube laser. In other words, you could remove the RF laser, install a glass tube laser and power supply, but the controls are not designed to drive it. In my case, I upgraded my controls first to DSP (some photos are shown earlier in this thread) which could drive an RF or Glass Tube Laser. Ran that for a little while, then changed out the RF laser to glass tube and new PS. I am very happy I did that for a couple reasons. 1. It confirmed that the laser was the bulk of my problems. 2. I now have current electronics with modern features and capabilities rather than 20 year old controls. So at this point it was easy to convert to a glass tube laser, but leaves me with the option to go back to the RF tube if I decide to invest in that again later. Don't get me wrong, RF Lasers are the Cadillac, but at this point, I am not noticing any shortfalls with having my glass tube laser, but this is just a hobby for me, I am not a business or doing production runs.

    When I priced things out, the recharge of the RF tube was going to be $1800 to $2500 (which involves more than just re-gassing, electronics in the laser need to be updated too.) I upgraded my entire controls, installed a new 40W glass tube laser and power supply (sized for higher wattage laser if I want to do that later), for much less than the $1800. I am a controls guy with a strong mechanical background, so I did all the modifications myself which made this an affordable option. My glass tube is mounted right where the RF laser was, with the original fan shroud over it to protect it. It was a fair amount of work to design and fabricate the mounting of it, but I designed it in a way that I can covert back to the RF tube very easily if I decide to do so later. I can tell you that the water cooling is much quieter than all those fans running for the RF laser which is a small added bonus.

    The ULS25PS, mechanically, is an awesome machine to start, and with an 18X24 inch bed. One other side note on a controls upgrade, I installed more powerful stepper drivers that drive my Z axis (table height) effortlessly. The original controls for the Z were unable to drive it in the upward direction without reaching in and helping it up by hand. You have a good base machine to start with, but quite a bit of work ahead of you... It's worth it though!!



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    Default Re: Rebuild log Universal Laser Systems 25PS

    Quote Originally Posted by Corrupted View Post
    Would it be worth it to try to fix the tube? Should I start with the lens and mirror? Is Cgerber's method of replacing it with a liquid cooled tube easier/better/cheaper? Sorry for the flood of questions, this is my first foray into laser stuff. I know this could be an awesome machine with a bit of repair. I'll definitely give the lens(es) and mirror(s) a check next time I'm at the space.
    1.) Check your mirrors and lenses. They by far are the most common thing to go bad and the cheapest to repair.

    2.) If not that tube is the next thing up to look at. cgerber post is a great on that topic. HVDC is cheaper in the short term (depending on how much of the other stuff you have to upgrade) than a rebuild (call on the rebuilds with your model and sn laser head and they can tell you if they can do just a regas or if electronics are needed). But depending on use RF is cheaper since you will only get a few 100 hours off a HVDC tube before it has to be replaced (typically no way to rebuild or refill)

    P.S. if you do decide to go the HVDC tube path let me know what your asking for the old RF tube. I am still debating what I want to do and if I could get a RF core for cheap enough I would give it a try.



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    Default Re: Rebuild log Universal Laser Systems 25PS

    Quote Originally Posted by wireb View Post
    But depending on use RF is cheaper since you will only get a few 100 hours off a HVDC tube before it has to be replaced (typically no way to rebuild or refill)

    If you're trying to help a guy, give him advice, not bull****.

    Sure, some bad / cheap glass tube only last hundreds of hours, but good (still cheap for what they are) looked after tubes last thousands of hours.

    a thousand bucks for 250 hours is 4 bucks an hour, a thousand bucks for 10,000 hours is 10 cents and hour, and at that rate tube cost per hour is less than electricity consumed per hour.



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    Default Re: Rebuild log Universal Laser Systems 25PS

    All of the reading I have done on DC tubes have stated their run life is much shorter than a RF tube for engraving. Agree the cheap china tubes are the shortest of the bunch. But even on the US made tubes the longest life I have seen advertised is 5k hours. On the other hand the RF tubes are rated for 45K+ hours. Example RF head: 25W CO2 laser with proven operating lifetimes of more than 45,000 hours, only from Synrad the worlds leading manufacturer of sealed CO2 lasers So based on mfg data no BS there. Now like I said if your not doing daily heavy use the cost advantages of a DC tube may well outweigh the operating hours of a RF. Both types of tubes degas over time so even if it just sits on a shelf and is not being used the clock is ticking and more than likely will not work after 5 to 10 years.

    If you have a link to a 10K+ HVDC tube please pass it along getting close to the point were I need to start thinking about buying the laser head.



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    Default Re: Rebuild log Universal Laser Systems 25PS

    Quote Originally Posted by wireb View Post
    All of the reading I have done on DC tubes have stated their run life is much shorter than a RF tube for engraving. Agree the cheap china tubes are the shortest of the bunch. But even on the US made tubes the longest life I have seen advertised is 5k hours. On the other hand the RF tubes are rated for 45K+ hours. Example RF head: 25W CO2 laser with proven operating lifetimes of more than 45,000 hours, only from Synrad the worlds leading manufacturer of sealed CO2 lasers So based on mfg data no BS there. Now like I said if your not doing daily heavy use the cost advantages of a DC tube may well outweigh the operating hours of a RF. Both types of tubes degas over time so even if it just sits on a shelf and is not being used the clock is ticking and more than likely will not work after 5 to 10 years.

    If you have a link to a 10K+ HVDC tube please pass it along getting close to the point were I need to start thinking about buying the laser head.


    Make 100,000 units, have just one that is babied in lab conditions and only ever runs at 5% rated power, wait till clock ticks enough operating hours, check tube is still able to output 5% power (by driving it at 100% now, not at 5% as at the beginning) make claim about 45k hours.

    Parallax, a USA company, give a standard FOUR YEAR warranty on all their glass tube lasers......, lemme see, 365 x 24 = 8,760 so 8,760 x 4 = 35k hours.

    That's not "We have a MONSTER advertising budget and we once made a cavity that did 45k hours" that's "Everything we sell has a 4 year warranty"



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    Default Re: Rebuild log Universal Laser Systems 25PS

    I have a ULS-25 with a bad controller. I've used it for years and am happy with its RF laser. I want to upgrade it to a DSP controller.

    How do I control my laser, since it just has a coaxial cable controlling it???

    I would really appreciate any help with this. I have the rest of the project under control, I believe.






    Nicholas



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    Default Re: Rebuild log Universal Laser Systems 25PS

    Hi Nicholas, I ran my ULS25PS with DSP Control and the original RF Laser for a while. The two connections of the coax (shield and center conductor) were wired to the Laser output on my DSP control to the terminals marked GND (shield) and PWM (center conductor). The software parameters will require the the Laser type to be RF. Worked very well for me.

    I am curious on your project, what DSP control are you planning to use, and I would be very interested in some installation photos when you are done, curious to see how you use the existing space in the control area for your conversion.

    Thanks. Chris...



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    Default Re: Rebuild log Universal Laser Systems 25PS

    Hi All
    Very interesting threads and also very useful.

    I managed to find an old ULS25PS very cheap / sold as spares. After having a quick play it was clear the 24V power supply / motor driver module was blown and so decided to replace the electronics..
    I went for the Wantai stepper drivers after reading the bad press on the ones here and I bought a Chinese DSP laser controller - LC980B. I am still in the middle of wiring but it seems to fit quite nicely.
    The plan is to use the existing RF laser (if it works) and then swap to a 50W CO2 when I have some more money.

    I have a couple of questions :
    a. Is there a way to move the table up / down manually (Z Axis) ?
    b. Regarding the X / Y limit switches - what voltage do they need 24V? and do they need any current limiters (in line resistors?)
    c. To set the Wantai drivers I need to know the number of steps per rev ? any ideas ? or what setting would be best ?

    heres the table

    Rebuild log Universal Laser Systems 25PS-497395351_083-jpg

    Thanks
    Adrian



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    Default Re: Rebuild log Universal Laser Systems 25PS

    Hi Adrian,

    That is awesome that you have found a ULS25PS and are planning to bring it back to life. It is an older machine, but a real workhorse, and built heavy duty. I will try to answer your questions based on experience with my machine upgrades.

    a. Is there a way to move the table up / down manually (Z Axis) ?
    Not that I am aware of because the Z motor is coupled directly to the Z axis lead screw shaft, and no manual override is available. If the stepper is unpowered, you may be able to rotate the coupler a little by hand just to get the table out of the way for working on things, but no manual option for normal use.


    b. Regarding the X / Y limit switches - what voltage do they need 24V? and do they need any current limiters (in line resistors?)
    These are photo detectors; Omron EE-SH3
    Image below of spec details

    Rebuild log Universal Laser Systems 25PS-omron-ee-sh3-jpg

    c. To set the Wantai drivers I need to know the number of steps per rev ? any ideas ? or what setting would be best ?
    Here is how I connected my stepper drivers, steps per rev is also shown (see attached image)
    Rebuild log Universal Laser Systems 25PS-stepper-drivers-jpg

    I am anxious to see photos of your project as you go along. Please provide updates.
    Good luck! Chris...



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    Default Re: Rebuild log Universal Laser Systems 25PS

    Quote Originally Posted by cgerber View Post
    b. Regarding the X / Y limit switches - what voltage do they need 24V? and do they need any current limiters (in line resistors?)
    These are photo detectors; Omron EE-SH3
    .
    Thanks Chris
    If I had taken one off to investigate I might have spotted this sooner !! In the end I had to remove it to figure out the wiring
    and I discovered the Anode/Cathode Emitter/Collector were clearly marked (with a magnifying glass) on the underside of the photo detector.
    I built a little resistor array circuit to control them using the 5V off the DSP and it seemed to work OK.

    I have a small issue now in that the Y limit is reached first and the X limit isnt tripped because its too far away.
    Im hoping that I can tell it that the Y limit is -25 mm back so the X can trigger too. If you set it manually ie push the Y
    all the way home - the X does stop correctly. The DSP instructions arent very helpful.

    I note you changed the Y motor for one that does 0.9 degree steps instead of the 1.8 degree one it comes with.
    Did that improve the accuracy or speed etc. I dont want to spend money unless there is some gain :-)

    regards
    Adrian



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    Default Re: Rebuild log Universal Laser Systems 25PS

    Hi Adrian,

    I am not familiar with the controller you have, so I am not sure that I understand the homing problem you are having.

    Regarding my Y motor, I think this is the original Y motor that came on the machine. I bought my machine second hand, but I don't think the Y motor was ever changed. I am pretty sure it is needed at 0.9 degree steps for accuracy and resolution. Is your Y motor 1.8 degree?

    Thanks. Chris...



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    Default Re: Rebuild log Universal Laser Systems 25PS

    Hi Chris
    On closer inspection my motors are the same as yours - both X and Y steppers 0.9 degree.
    Im impressed that these were already fitted 15years ago - a very nice starting machine indeed. I have upped my micro stepping to 3600 to match.

    The homing problem is because the Y sensor beam gets broken whilst the carriage is about 30mm off the back wall and stops
    and so the X sensor beam never gets broken because its too far away. So I sort of need to tell it the true Y origin is - 30mm so it travels a bit further.

    Heres a crude drawing
    Rebuild log Universal Laser Systems 25PS-datumproblem-png

    regards
    Adrian



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    Default Re: Rebuild log Universal Laser Systems 25PS

    Hi Adrian,
    I see, the homing you are describing makes sense to me now. I ran into this same problem when I upgraded to DSP control. I am not sure exactly why, as this was a couple years ago for me, but I wonder if the original control had some sort of delay, or traveled extra steps after first seeing the flag. I fixed it on my machine by drilling and tapping new mounting holes and relocating the photo eyes. It is interesting in that I had to relocated both the X and Y home photoeyes, about the same distance for both if I remember correctly.

    Chris..



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