Problem with a GCC Mercury LaserPro

[Lars Karlsson]

I´m using a GCC Mercury LaserPro system that have a Synrad 48-5 laser.
Overall the system works well but I have a question, there is one thing I don´t understand...
The Synrad 48-5 laser is a dual head laser aplication 25+25 W. I´m reading between 20-23 W on the output of each of the the two lasers, which I think is ok.
But when I run the two laser together ( normal mode ) I don´t get more than about 25 W total, and I don´t understand why !?
I have lined up the to lasers, direct from the laser output and at a distance of 4 meters (about 13 feet) they line up well.
Is there anyone out there who can help me understand what´s going on...???
Regards
Lars

[Richard Rumancik]

Hi Lars and welcome . . .

I am confused as to what you are saying. Dual-head as far as I know means two carriages, not two laser sources. The 48-5 is designed to combine two Synrad 25 watt sources optically in one package so it looks like a 50 watt source. I don't understand how you are able to operate each one separately as they are a combined unit with a single output beam. The optical alignment should be all done internally so I don't know what you are actually doing when you say you aligned the two beams. Are you able to activate one souce at a time using the test routines?

Please clarify and maybe someone can help - it almost looks to me like you have a 50 watt laser tube which is operating at 25 watts which is not unexpected if the tube is several years old. What is the date code on the tube?

If you are truly getting 25 watts out of each section independently then it would seem that you have somehow not turned on the full laser power. Is there a driver setting or firmware setting for doing that? I am not familar with this tube - I would have thought that if you asked for say 30 watts each sub-unit would output about 15 watts, and if you ask for 100% power you should be getting the full 50 watts - if the tube can deliver it.

[Lars Karlsson]

Hello and thank you very much!

Ok, well then I don´t have a dual-head laser :)... (english isn´t my first language as you may have figured out :rolleyes:)
It has got two laser sources and as you wrote combines two Synrad lasers. Operating them separately isn´t that hard, each laser is conected to the circuit board using a common RCA cable (like you use to connect audio gear). I just unplugged one of them and then you operate one of the lasers.
The alignment is done in the housing of the two lasers using mirrors and a lens (it´s not just a lens but I don´t even know the swedish word for it). When I bought it the two beams where missaligned, so I opened the housing and corrected the allignment of the two beams, using these mirrors. In the beginning this worked out pretty good, when I meassured the output I got around 60W, which would suggest that I had my 50W.
But now after like 3 or 4 months I down to 25W but this time the beams are not missaligned.

The two laser sources should be ok, they have been refilled and checked for errors by a company in GB and the output from each of them is about 20-25W.
Could this be a software problem? If the lasers aren´t triggered at the exact same time could this lead to some sort of interference?

I don´t know if you understand what I mean now...it is hard to describe the problem in swedish, even worse in english! :D

regards
Lars

[Robert Walters]

Lars,

The manual and other documents are available for download from here:
http://www.synrad.com/48series/48_50.htm


You said "RCA", are you sure you didn't mean "BNC" (do you HAVE to twist it to remove it)?

Can you check/confirm you are getting the proper signals to those connectors?
Are they using a "Y" or "T" cable/connector to combine the signals?
You could have poor/bad wiring somewhere.

It sounds like you have a laser power meter,
Can the measure the output of each laser individually?
Are they both firing at the same time?

[Richard Rumancik]

. . . Ok, well then I don´t have a dual-head laser :)... (english isn´t my first language as you may have figured out)

Your English is very good - no worries there.


. . The alignment is done in the housing of the two lasers using mirrors and a lens (it´s not just a lens but I don´t even know the swedish word for it). When I bought it the two beams where missaligned, so I opened the housing and corrected the allignment of the two beams, using these mirrors.

Did you have technical documentation to help you do this? You were brave to open it up - it sounds like you were succesful. Was this done before the tubes were refilled? I would have thought that if a company was re-gassing the laser assembly that they would be expected to realign the beams if needed.


Could this be a software problem? If the lasers aren´t triggered at the exact same time could this lead to some sort of interference?

Since it has gone down to approximately half power it would seem to me that one of the lasers isn't firing at all. How are doing the measurement for each source? Are you in diagnostic mode, using a power meter at the table? How are you enabling one laser source at a time for your test? Is there a switch or is it enabled in firmware?

The two internal lasers are numbered 1 & 2. (The panel is marked Fuse 1, Fuse 2 and CTRL 1 and CTRL 2). So you should be able to determine if LAser 1 or Laser 2 is dead. For example if you remove Fuse 1, do you get 25 watts at the table? If yes, that would imply that Laser 1 is causing the problem and Laser 2 is good. That could also be caused by a failed input to Laser 1, not necessarily the Laser 1 itself. (Possibly cables, as Robert suggested.) Perhaps switching CTRL 1 and CTRL 2 cables would tell you if the main board is outputting the proper signals and if both "channels" are working? (ie. if switching the CTRL cables causes the opposite laser to fire then, you know both lasers are okay and the problem is upstream from the lasers.) I would contact Synrad and get some advice before doing this as I am not entirely familiar with the 48-5. Synrad has provided very good assistance to me in the past even though the laser system is made by GCC.

Keep us posted on your progress . . .

[Lars Karlsson]

Ok, so right now everything seems to be working as it should and I think I´m the one to blame!!!
I´ve been using only one laser for 2-3 months when engraving on a really soft plastic material. Figured I only needed 25W and this could be what caused the problem. I the manual for this Synrad laser it says you can use only one laser for a while if one breaks down. And well 2-3 months is a while...the manual doesen´t tell you what happens "after a while" but loss of power maybe is one the things that can happen.
I discovered the problem last week when I needed all the power I could get to cut a thicker material.
So I think the problem solved itself. These last 4-5 days I´ve been testing and meassuring the power with both lasers on and suddenly yesterday I got about 60W...and a day later still has 60W!

You guys asked some questions, don´t know if you´re still intressted, but I´ll try to answer them anyway;

- Robert

* The lasers has BNC connections, A T-connector with 2 BNCs in one end and a RCA in the other end. The RCA is then connected to the circuit board.
* I think the wiring is ok, I got good readings from an oscilloscope.
* I can meassure each laser individually. But the problem is that I still don´t know if they are firing at the same time. I think so but not sure.

- Richard

* I didn´t have a technical documentation, but I got the machine really cheap and it´s really hard to find someone here who knows how
these lasers work in sweden, so it was trial and error. I did this after the tubes were re-gassed. The company in GB had realigned the lasers,
but I think something happened when it was shipped back to sweden. Not everyone knows what "fragile" means apparantly :-).

Here is a picture showing the inside of the laser. The two lasers I and II and the mirrors/optics.
291059


regards
Lars

[Richard Rumancik]

Glad to hear it is working again but I still don't understand why the tube stopped working and then came back up suddenly.


. . . the manual for this Synrad laser it says you can use only one laser for a while if one breaks down.

So they mean that in a failure situation you can still run with one tube - but it was not intended to run permanently like that? I take it that you manually overrode the system software somehow to allow only one laser operate. (Did you unplug one tube?) I would guess that if you need say 40 watts total, each laser would normally put out 20 watts, and if you need 25 watts each laser would normally put out 12.5 watts. Is this correct? Why did you decide to override the normal mode of operation? Were you trying to reduce wear on the one tube? It sounds like the design was not intended to be used this way - although I don't know what would be wrong with it.

I don't know why there would be a "time limit" on using a single active tube - I assume there must be some kind of thermal effect.

Good that you are back operating but I don't think we really know exactly why it stopped and why it recovered.

[Robert Walters]

* I can meassure each laser individually. But the problem is that I still don´t know if they are firing at the same time. I think so but not sure.


Lars,

You could just put a piece of masking tape over the optics and fire a single pulse.
If you see burnt spots on both, you know they are both firing at the same time.


The whole "one laser for a while" thing may be related to a duty cycle.

If you need 30W total, that's 15W each, so you are not pushing each laser to it's limits.
Heat generated internally is distributed between both lasers;
Less heat per laser, more thermal mass per laser to distribute that heat.
Less overall wear and tear (so to speak would be my guess).

[Lars Karlsson]

I´m not sure what happened. Right now everything seems to be working and has done so for about a week...whoho!!!
Yes, I just unplugged one tube because I didn't need much power at all. I was engraving on a very soft plastic material. Only needed to use 50% power on one laser. Didn´t think this would cause a malfunction.

From what I understand, in my case I have two 25W lasers and they allways put out 25 Watts, in total 50 Watts. If you don't need all that power, let's say you only need 50%, the laser still fires on full power but for a shorter time period. Half the time (50%) compared to full power. The signal to the laser is a square wave with a period of 200 microseconds. So full power means that the laser will fire for the whole period. 50% power means that the laser will fire for 100 microseconds and then rest for 100 ms and so on.
I only needed 50% power from one laser to engrave.
Don't know if this answered your question about the output of the laser. If not feel free to ask again and I will try to explain again :-)

Regards Lars

[Lars Karlsson]

A clever!
Well it seems they are firing at the same time and right now everything works fine. Must be a wiring problem as you wrote earlier :-).
And now the damn thing has been working fine for a week...
Heat shouldn´t be a problem in my case beacause my lasers are liquid(water) cooled. The cooler is allmost as big as the mercury engraver itself :-). I monitored the temp. and it never got higher than 20 degrees celcius (68 degrees fahrenheit)

Regards
Lars

[Robert Walters]

Lars,

Good to hear it's working as it should.

Now, just keep your hands off all the wires =)

[Allen Rawley]

Ok, so right now everything seems to be working as it should and I think I´m the one to blame!!!

* I didn´t have a technical documentation, but I got the machine really cheap and it´s really hard to find someone here who knows how
these lasers work in sweden, so it was trial and error. I did this after the tubes were re-gassed. The company in GB had realigned the lasers,
but I think something happened when it was shipped back to sweden. Not everyone knows what "fragile" means apparantly :-).

Here is a picture showing the inside of the laser. The two lasers I and II and the mirrors/optics.
291059


regards


Lars

Hello Lars,

Wondering if you could do me a favor and post a few additional photos of your laser mounted in your Mercury?

I am upgrading a Mercury 1, Synrad 25 to a Synrad 50 water cooled, and would like to understand the mounting and water cooling configuration.

Thanks!
Allen

[Chuck Stone]

I am upgrading a Mercury 1, Synrad 25 to a Synrad 50 water cooled,

I didn't know you could do that. GCC told me it wasn't an option.

[Killor Perez]

Hi Lars

Would you know tell me that uses mirrors or lenses DOUBLE laser tube Synrad?

Thank's