Laser burning a hole in the back of my case.

[Ted Hunter]

I purchased a new 150 Watt laser 3 months ago. (Chinese 37 X 48" bed, purchased through a U.S. Company. Tube says 160 watt) I have been very pleased with this machine (and the company I bought it from) as it did all that I had expected.
I really like this machine for what I bought it for (Cutting shapes into 1/16" rotary cut maple veneer) and all the other projects I have been thinking up. Amazing machine!

From day one the machine has reflected some of the tube energy off the splitter mirror, onto the back case when running. This easily burns through masking tape placed on the case. Company said this was OK.
Two weeks ago it stopped cutting properly at the speed and power I normally run it at, speed 80 and a power of 100. After testing I would say it is almost half as strong as when I bought the unit.

What I have done to try to solve the problems:

- Leveled the bed of the table. It was slightly out and now has a consistent level over its entire surface.
- Changed the lens at the cutter nozzle and made sure they were clean.
-Removed, tested and changed the splitter lens at the ruby red laser, just in front of the laser. (did not help the burning on the case)
-Aligned all the mirrors correctly and cleaned.
-Tested the power supply with the equipment and instructions provided when purchased. (big resistor n such) Lots of power.

The unit has a mA meter built into it. When I first bought the unit when running at 100% power it would read around 40 mA now it will not go over 10mA when running at the same settings but the power supply test seemed OK.

This week the tech told me I should never run the laser at 100%. This was news to me as it is not in any literature I have gotten from them and when I first was setting up the machine tech support said nothing about this. We have a similar sized machine where I teach and they always run their machine at 100% without ant problems.
I am confused by this.

My questions are;

Where did the mAmps go when the power supply test says it is OK?

Is it normal to have reflected energy from the beam splitter hitting the back of the unit?

Is it wrong to run it at 100% power? It does not run continuous during the day when in use.

Any insight on my next step from the form would be great as I am running out of Ideas.

Thanks for listening.
Ted

[Dan Hintz]

My questions are;

Where did the mAmps go when the power supply test says it is OK?

Is it normal to have reflected energy from the beam splitter hitting the back of the unit?

Is it wrong to run it at 100% power? It does not run continuous during the day when in use.

I'm sure Dave will kick in here with the proper current rating for a 150W tube... I'm not familiar with units that crank that high, so he'll be the authority on it. 100% is fine if that value does not exceed the "comfortable max" rating of the tube... 100% at 30mA is vastly different than 100% at 40mA, so it's a loaded question in that regard.

It is never normal to have some beam split off into random areas of the machine. Everything should come out of the partially-silvered end and hit the first mirror with no stray radiation. If they told you that was acceptable, it was a bold-faced lie and they should be screamed at for it (literally, I would be screaming into the phone for such stupidity).

[Dave Sheldrake]

Max Q on a genuine 150 is 32mA (and that is real max) 28 - 30 is much safer for tube life.

40mA will kill even a 220 watt DC tube :(


EFR ZN & ZX series


ZN-1250:
Length: 1250mm +/- 20mm
Diameter: 80mm +/- 2mm
Rated Power Output: 80 Watts
Maximum Power Output: 95 Watts
Working Current: 26 Ma

ZN-1450:
Length: 1450mm +/- 20mm
Diameter: 80mm +/- 2mm
Rated Power Output: 100 Watts
Maximum Power Output: 120 Watts
Working Current: 28 Ma

ZN-1650:
Length: 1650mm +/- 20mm
Diameter: 80mm +/- 2mm
Rated Power Output: 130 Watts
Maximum Power Output: 150 Watts
Working Current: 30 Ma

ZN-1850:
Length: 1850mm +/- 20mm
Diameter: 80mm +/- 2mm
Rated Power Output: 150 Watts
Maximum Power Output: 180 Watts
Working Current: 30 Ma


F Series:

F2:
Length: 1250mm +/- 20mm
Diameter: 80mm +/- 2mm
Rated Power Output: 80 Watts
Maximum Power Output: 95 Watts
Working Current: 28 Ma

F4:
Length: 1450mm +/- 20mm
Diameter: 80mm +/- 2mm
Rated Power Output: 100 Watts
Maximum Power Output: 120 Watts
Working Current: 30 Ma

F6:
Length: 1650mm +/- 20mm
Diameter: 80mm +/- 2mm
Rated Power Output: 130 Watts
Maximum Power Output: 150 Watts
Working Current: 30 Ma

F8:
Length: 1850mm +/- 20mm
Diameter: 80mm +/- 2mm
Rated Power Output: 150 Watts
Maximum Power Output: 170 Watts
Working Current: 30 Ma

F10:
Length: 2050mm +/- 20mm
Diameter: 80mm +/- 2mm
Rated Power Output: 180 Watts
Maximum Power Output: 195 Watts
Working Current: 30 Ma

RECI

W Series:

W2:
Length: 1120mm +/- 20mm
Diameter: 80mm +/- 2mm
Rated Power Output: 80 Watts
Maximum Power Output: 85 Watts
Working Current: 27 Ma

W4:
Length: 1400mm +/- 20mm
Diameter: 80mm +/- 2mm
Rated Power Output: 100 Watts
Maximum Power Output: 120 Watts
Working Current: 28 Ma

W6:
Length: 1650mm +/- 20mm
Diameter: 80mm +/- 2mm
Rated Power Output: 130 Watts
Maximum Power Output: 150 Watts
Working Current: 30 Ma

W8:
Length: 1850mm +/- 20mm
Diameter: 80mm +/- 2mm
Rated Power Output: 150 Watts
Maximum Power Output: 180 Watts
Working Current: <30 Ma

[Rich Harman]

It might be helpful to know what US company you purchased the laser from, so that others may steer clear of them. They clearly did not inform you properly.

The mA meter is what tells you the power going in to the laser, not the setting. The power supplies are adjustable so that 100% is just a number. You need to correlate the power setting with the reading on the ammeter to determine what settings are appropriate. The company you bought it from should've adjusted it for you. Apparently they didn't.

It sounds like the beam is bouncing off the beam splitter for your red dot laser. Many people remove those things as they are not worth the trouble. Instead use a laser that is mounted along side the laser head.

[Ray Scott]

Glad to see you are asking for help here on SawMillCreek... Sounds like the company and technicians at that other company have led you into damaging your laser machine.

We can try to help you here. Could you please post your results from testing the laser power supply? You connect the big resistor and the power meter. What milliAmps did you get at 50% output? 75% output? 100% output?

My advice... use your laser between 15% and 85% .. Using your laser at over 85% is like driving your car beyond the red line.... all day long. That's great .. If you drive in a NASCAR race. But those guys only expect the engine to last one race.

Get rid of the red-dot pointer injection. The beam splitter (prior to the first mirror) often reflects too much light.. It costs you about 8 to 15 percent of your laser power. It isn't worth the power loss .. or damage it causes.


I just want to clarify... Ted Hunter did not purchase that laser from Rabbit Laser USA. As of current knowledge, Rabbit Laser USA does not sell glass laser systems over 80 watts. If not taken care of with the utmost attention, the high-output laser power glass tubes have been known to melt the interior glass walls, distort the glass tubes, degrade the output coupler lens, thermal distortion of the internal rear mirror. Once the gas and/or glass is damaged, the High Voltage DC electricity looks for somewhere else to go. That HVDC electricity will likely arc to the frame or arc through the glass and/or epoxy to travel through the coolant.

[Ted Hunter]

Glad to see you are asking for help here on SawMillCreek... Sounds like the company and technicians at that other company have led you into damaging your laser machine.

We can try to help you here. Could you please post your results from testing the laser power supply? You connect the big resistor and the power meter. What milliAmps did you get at 50% output? 75% output? 100% output?

My advice... use your laser between 15% and 85% .. Using your laser at over 85% is like driving your car beyond the red line.... all day long. That's great .. If you drive in a NASCAR race. But those guys only expect the engine to last one race.

Get rid of the red-dot pointer injection. The beam splitter (prior to the first mirror) often reflects too much light.. It costs you about 8 to 15 percent of your laser power. It isn't worth the power loss .. or damage it causes.


I just want to clarify... Ted Hunter did not purchase that laser from Rabbit Laser USA. As of current knowledge, Rabbit Laser USA does not sell glass laser systems over 80 watts. If not taken care of with the utmost attention, the high-output laser power glass tubes have been known to melt the interior glass walls, distort the glass tubes, degrade the output coupler lens, thermal distortion of the internal rear mirror. Once the gas and/or glass is damaged, the High Voltage DC electricity looks for somewhere else to go. That HVDC electricity will likely arc to the frame or arc through the glass and/or epoxy to travel through the coolant.

I have to thank everyone for the replies and all the information.

Right, it is not a Rabbit Laser product. It is a glass tube. I really do not want to bad mouth online, a company I still have to deal with. Up until now they have been available, even on a Saturday for me and they have been willing to send me lenses ASAP in the hopes of resolving the problem. They I think are as frustrated as I and do want to resolve the problem. However it has been all about adjusting and cleaning lenses and other than an email to them suggesting we look at the tube and power supply(did not respond) we have not talked about what else it could be. (miffed however about not telling me about the power setting)

When the problem first started (almost 3 weeks ago) the mA meter was up around 40% when the machine was cutting and the power at 100%. Took a picture of it firing for them.
309193

Then last week, on Tuesday after a lot of fiddling and talking with the tech online they informed me that the laser should be run at 80%. First I had heard. That day we were able to cut veneer but it was obvious it had lost power. During the week while running the machine my operator noticed the meter had dropped to around 10% at 80% power. (I tried 100% power and it was similar) I took another picture of the meter then. This is when I decided to do the test with the big resistor. I have not talked with them about the lack of power at the meter or the test I did yet.

When I did the resistor test I did not test it at different power levels. There is a small plugin that came with the machine. During the test I disconnected the plugin to the power supply that I think controls the power from the panel or computer and replaced it with the provide plugin dongle thing. I did my test with this installed. The meter bounced up to 50ish mA when I pushed the test button on the power supply.

I can do the resistor test again at the levels you asked but do I set the power at the machine panel and do I install the little plug into the power supply? I think so.
I will not do anything until you get back to me.
I will only run the laser at 85%.
I will also remove the splitter lens and not use it.


I just want to clarify... Ted Hunter did not purchase that laser from Rabbit Laser USA. As of current knowledge, Rabbit Laser USA does not sell glass laser systems over 80 watts. If not taken care of with the utmost attention, the high-output laser power glass tubes have been known to melt the interior glass walls, distort the glass tubes, degrade the output coupler lens, thermal distortion of the internal rear mirror. Once the gas and/or glass is damaged, the High Voltage DC electricity looks for somewhere else to go. That HVDC electricity will likely arc to the frame or arc through the glass and/or epoxy to travel through the coolant.

That sounds scary.
I have had a good look at the tube and there are no cracks that I can see. One thing I did notice was at the beam exit hole just inside the tube there is a inch..ish metal tube that the beam passes through just before it exits the tube. There is a small amount of energy hitting the metal and flowing over it when it is firing. I do not know if this is normal.

I will keep an eye on the tube for any of the symptoms you have mentioned. Thank you.
I want to have some solid info before talking with the tech again in the case it is the tube that is at fault.

Thanks again for spending time with me on this.
Ted

[Ray Scott]

I have read all the info that you have put forth here... I believe it is a damaged laser tube... The best case would be a damaged laser power supply. I would expect that the company that sold you the laser machine is not so willing to just send you the laser power supply or laser tube... At least not based on a quick test. You should conduct some detailed tests and prove to that company that you have really worked on this problem as far as you technically can go. You need to do the testing quickly and provide detailed results.. photos, videos, documented results. As with any product and service agreement... If you don't get the warranty results that you expect (and what you paid for).. advise that company that you are willing to go forth with a lawyer.

[Dan Hintz]

Just a side note Ted... the meter is showing you mA, not %. When you post your meter reading with a percentage sign it confuses the issue. Your meter is showing 38mA, not 38%.

[Ted Hunter]

Just a side note Ted... the meter is showing you mA, not %. When you post your meter reading with a percentage sign it confuses the issue. Your meter is showing 38mA, not 38%.

Thanks Dan for all the info and above.
Can you answer this question.
I can do the resistor test again at the levels you asked but do I set the power at the machine panel and do I install the little plug into the power supply? I think so.
Thanks again for your insights.
Ted

[Dan Hintz]

I can do the resistor test again at the levels you asked but do I set the power at the machine panel and do I install the little plug into the power supply? I think so.

You want the meter to max out at 30mA when you engrave at 100%... this will require tweaking a small pot on the power supply. Once that value is set, you can engrave to your heart's content without worrying about overpowering the tube. Though that doesn't do you much good if the current tube is already stuffed.

[Ted Hunter]

You want the meter to max out at 30mA when you engrave at 100%... this will require tweaking a small pot on the power supply. Once that value is set, you can engrave to your heart's content without worrying about overpowering the tube. Though that doesn't do you much good if the current tube is already stuffed.
Thanks for all.
Ted

[Dave Sheldrake]

When the problem first started (almost 3 weeks ago) the mA meter was up around 40% when the machine was cutting and the power at 100%. Took a picture of it firing for them.

That's the reason they are telling you to try running at no more than 80% as at 38mA 80% is 30.4mA and within safe margins for the tube. What it also tells me is that if they know anything about lasers they will suspect the tube or the psu or both are damaged by the over-current situation.


I want to have some solid info before talking with the tech again in the case it is the tube that is at fault.

Hows this for solid?

The machine has been set up to run at 20 - 25% OVER the maximum safe rating for that tube, there are two possible causes 1: it has not been checked before it was sent out or 2: it was checked but the high output is what puts it in the 150 watt range.

How long is the tube? (I'm checking to see if it is a real 150 or an over - run 120 that's being forced to output 150, a common practice on Chinese machines from some sources)

DON'T run the machine until the problem is solved, or at least the cause is ascertained, as Ray said, the things that can happen can be dangerous and happen way faster than you will be able to react to. At best you run the risk of causing a lot more damage to both the tube and PSU if they aren't already cooked.

I can understand you wanting support from your supplier Ted but being blunt the kind of advice and support you have had so far I could happily live without. This is the result of people who know little about DC lasers getting involved with selling them!

cheers

Dave

[Ted Hunter]

That's the reason they are telling you to try running at no more than 80% as at 38mA 80% is 30.4mA and within safe margins for the tube. What it also tells me is that if they know anything about lasers they will suspect the tube or the psu or both are damaged by the over-current situation.



Hows this for solid?

The machine has been set up to run at 20 - 25% OVER the maximum safe rating for that tube, there are two possible causes 1: it has not been checked before it was sent out or 2: it was checked but the high output is what puts it in the 150 watt range.

How long is the tube? (I'm checking to see if it is a real 150 or an over - run 120 that's being forced to output 150, a common practice on Chinese machines from some sources)


79" long
3" across its width.

This is the sticker on it. the wattage rating has been rewritten. It was like this when I got the machine.
309257

Power supply
309258

[Ted Hunter]

Just talked to the company and they are sending me out a new tube without any questions asked. Tech was very supportive.
It is not the same brand tube as what I have and said the new one is a better brand. Forgot to ask what it is.
Now I wait.
Keep you posted.
Thanks
Ted

[Dave Sheldrake]

That's a PRC 2000 tube, rated at 180 watts max with a 35 mA current max Q.

The MYJG150 supply has an absolute MAX output of 38mA so it seems it hasn't been adjusted since installation. In effect a budget tube has been fitted with a budget PSU to keep costs down, if a new tube is fitted without the current being adjusted on that supply it will kill the new tube pretty quickly and is very likely the reason behind the first tube dying too :( higher grade tubes like EFR and RECI don't like to be run over-current, more so than cheaper tubes so probably good to check what make the new one is when it arrives and get their tech out to adjust the working current or you will be back here in a few weeks with the same problem.
It's also possible being run at the PSU's maximum available output may have damaged that as well so handle with care when you fit the new tube ;)

cheers

Dave