Sparks at the mirror

[Jeff Body]

Why does this keep happening to me? I'm just starting to actually get some business and now this.
I purchased the tube exactly 1 year ago from lightobject. It's been used very sparingly and I always keep the distilled water at around 20*C.
I was about 7 cups into a 60 cup order and now this.

Does this mean I need a new tube?


https://youtu.be/7BtGqGVA394

[Dave Sheldrake]

Yup, sadly that tube is knackered. The arc doesn't want to go down the tube on a good day so in this case is arcing to the path of least resistance...in your case that's the water supply at the full reflector end. So either the water is very conductive (you have additives in it) there is a bad connection on the tube (possible) or the tube is plain duff (likely)

Sooner or later that arc will loosen the glue at that end and the water jacket will fall off (seen it happen quite a few times)

[Jeff Body]

Thanks Dave.

I don't add anything to my water and It was changed out a few months ago.
I just wish I knew how this is happening. The original tube did a similar thing a year ago. I've only used this tube 20-30 hours over the last year.
I always check for air bubbles and I don't use the laser till I remove them. Right now it still fires a beam it just happens to spark at the same time.

I'm just tired of dropping $400-500 dollars a year on this.

[AL Ursich]

I would change the water and see if it makes a difference.

Just a WAG... Wild AL guess....

AL

[Jerome Stanek]

try distilled water

[Matt McCoy]

Your power supply is probably set too high, which is leading to short tube lifespan.

[Keith Winter]

How often do you run the tube Dave? Are you buying a generic or a brand name tube, if so what brand name?


Thanks Dave.

I don't add anything to my water and It was changed out a few months ago.
I just wish I knew how this is happening. The original tube did a similar thing a year ago. I've only used this tube 20-30 hours over the last year.
I always check for air bubbles and I don't use the laser till I remove them. Right now it still fires a beam it just happens to spark at the same time.

I'm just tired of dropping $400-500 dollars a year on this.

[Jeff Body]

I would change the water and see if it makes a difference.

Just a WAG... Wild AL guess....

AL

I'm going to try that tonight. I was too disgusted to troubleshoot it last night.


try distilled water

That's all I've ever used in the laser is distilled water


Your power supply is probably set too high, which is leading to short tube lifespan.

I've never gone over 20mA. The tube is rated at 22mA but I've never gone that high.


How often do you run the tube Dave? Are you buying a generic or a brand name tube, if so what brand name?

I'm assuming I'm getting a quality 60w tube from Lightobject.
It's made by SPT

[Clark Pace]

So I worked with a gweike mahchine and it would arc tubes. Gweike said I was supposed to have installed a rubber shieth around it. They sent me one and it solved the problem. It is made of insulating rubber

[Kev Williams]

I'm just tired of dropping $400-500 dollars a year on this.
I would be too, but if it's any consolation, I'm pretty sure service plans for western machines are around 3x that much, and usually only cover labor costs...

Last one offered to me by NH was over $1300 a year...

[Adam Herman]

you may want to look for de-ionized water, different from distilled and has a higher resistance, usually above 18 Mohm. distilled may be quite conductive as there is not a standard for the minerals in it.

[Keith Winter]

I'm going to try that tonight. I was too disgusted to troubleshoot it last night.



That's all I've ever used in the laser is distilled water



I've never gone over 20mA. The tube is rated at 22mA but I've never gone that high.



I'm assuming I'm getting a quality 60w tube from Lightobject.
It's made by SPT

Spt is at the cheap end of the scale... I didn't see how often you use it? If you go weeks at a time without using it this is going to happen to any tube. If you are using it regularly it can be a whole host of issues.

[Doug Fisher]

>>Gweike said I was supposed to have installed a rubber shieth around it.<<

Clark, what does this sheath cover? Just the end of the tube?

Thanks.

[Keith Winter]

Doug Google laser tube install

https://www.youtube.com/watch?v=Npg05rMQH1M
https://www.youtube.com/watch?v=eXk5wQ0Iq94

[Doug Fisher]

Ah, ok. He was talking about the sheath, usually cut from the silicon water tube, that goes over the electrical connection that most people fill with the white caulk-ish stuff? Sorry, I thought he was talking about sort of sheath that went over the tube or the whole end of the tube. Thanks for the clarification.

[Matt McCoy]

Ah, ok. He was talking about the sheath, usually cut from the silicon water tube, that goes over the electrical connection that most people fill with the white caulk-ish stuff? Sorry, I thought he was talking about sort of sheath that went over the tube or the whole end of the tube. Thanks for the clarification.

RTV silicone is used to fill the tubing over the electrical connection on the hot end. There is also a silicone sleeve on some tubes that is used in conjunction to cover a portion of the tube.

[Dave Sheldrake]

you may want to look for de-ionized water, different from distilled and has a higher resistance, usually above 18 Mohm. distilled may be quite conductive as there is not a standard for the minerals in it.

Nope...if you have a tube with an output coupler made of aluminium DW will turn it into swiss cheese very quickly

[Dave Sheldrake]

Sheathing it won't help and may mask the problem. Sheathing is to prevent tracking to the machine chassis (earth) that tube is tracking to the waater supply

[Jeff Body]

Well here's an update.

I have good news and I have bad news.

The Good news is my old laser tube is still working
The bad use is I bought a 60W laser tube for nothing.


Before I dove into replacing the tube I tested the current tube and it worked. I've since engraved the rest of this cup order (23 more cups without a problem). After looking REALLY closely at the tube it appears as though the sparks where on the outside of the tube. I suspect it built up enough condensation that it arched from the outside through the condensation, ran down the cooling hose and to the grounding plate I have below the tube in the extension.

I feel like I'm going to have to really monitor my water temps better and adjust it more often. The problem is I work in my garage which doesn't have AC. I'm at the mercy of the local dewpoint. After looking at some history the dewpoint has been between 68-75*F. This means I'm just going to have to run my chiller at the top of the operating range for the tube. Tonight I had the temp at 24*C without forming any condensation. That's the coldest I'm going to get til the humility goes down around here.
I've already ordered a meter to measure dewpoint in the garage. This way I can adjust the temp to prevent condensation.

Living in FL is GREAT!!!!!!!!

http://i52.photobucket.com/albums/g2/body80/Photo%20Oct%2002%2012%2039%2043%20AM.jpg (http://s52.photobucket.com/user/body80/media/Photo%20Oct%2002%2012%2039%2043%20AM.jpg.html)

[Tony Lenkic]

Nice work Jeff.

The marking is really rich black.

[Bert Kemp]

Thanks for the update glad your running again cups look good:)


Well here's an update.

I have good news and I have bad news.

The Good news is my old laser tube is still working
The bad use is I bought a 60W laser tube for nothing.


Before I dove into replacing the tube I tested the current tube and it worked. I've since engraved the rest of this cup order (23 more cups without a problem). After looking REALLY closely at the tube it appears as though the sparks where on the outside of the tube. I suspect it built up enough condensation that it arched from the outside through the condensation, ran down the cooling hose and to the grounding plate I have below the tube in the extension.

I feel like I'm going to have to really monitor my water temps better and adjust it more often. The problem is I work in my garage which doesn't have AC. I'm at the mercy of the local dewpoint. After looking at some history the dewpoint has been between 68-75*F. This means I'm just going to have to run my chiller at the top of the operating range for the tube. Tonight I had the temp at 24*C without forming any condensation. That's the coldest I'm going to get til the humility goes down around here.
I've already ordered a meter to measure dewpoint in the garage. This way I can adjust the temp to prevent condensation.

Living in FL is GREAT!!!!!!!!

http://i52.photobucket.com/albums/g2/body80/Photo%20Oct%2002%2012%2039%2043%20AM.jpg (http://s52.photobucket.com/user/body80/media/Photo%20Oct%2002%2012%2039%2043%20AM.jpg.html)

[Clark Pace]

Ah, ok. He was talking about the sheath, usually cut from the silicon water tube, that goes over the electrical connection that most people fill with the white caulk-ish stuff? Sorry, I thought he was talking about sort of sheath that went over the tube or the whole end of the tube. Thanks for the clarification.


I was talking about a sheath that covers the entire back of the tub. It's a few inches in diameter. So you were correct in your 1st thought. I got it from Gweike.

[Jeff Body]

Thanks for the update glad your running again cups look good:)


No problem
I always try and remember to update my post with the solution. One day someone's going to actually do a search and they'll find this post and it'll help them fix their own problem.

[Jeff Body]

Well...................
It died last night. I was going to work on some cups. I fired up the chiller and came back later to do some work. I decided before I setup the rotary I'd cut myself a few more focus measuring tools.
I loaded the file and hit start. The laser head moved but I had 0 output from the laser tube. About 10 sec in I got a huge arch from the tube to the chassis.

Good thing I have another tube.


So this started out as a ebay 50w blue and white laser. I've upgraded the mirrors, lenses, 1250mm 60W tube and 60W psu.
I've been thinking about maybe importing a china laser. Would the overall quality be better then what I have?
I working on and repair medical equipment for a living so repairing a laser isn't a problem
I'm just tired of how unreliable this ebay laser has been.
unfortunately I'm not able to afford a western laser.

So the question is? Is an imported laser from a recommended company found here > my modified ebay laser?

[John Lifer]

Well I really can't answer YET, but there are at least three of us here in the past 60 days that have ordered lasers from Dave Sheldrake's Woman In China :cool:

Blanca Yan at Ray Fine Lasers.

One should be arriving in the US about now, (Jason Hakki - Got it yet Guy?),
Mine is being tested this week, hopefully shipping in the next day or so. (a 1300mmx900mm)
And Ryan Matthews has an almost identical machine a few days behind mine.

I'm hoping mine will make it by mid November, give us till Christmas and we should all three be able to give you a solid opinion of Ray Fine Lasers.
I've been happy with the communication so far. Questions answers promptly by Blanca, decent price as compared to other Chinese manufacturers.
NO movement on price, If you desire close quotes on 500x700, 600 x400 or 1300x900, let me know and I'll shoot them to you.

Now the machine looks like the eBay machines, one thing they have added is std amp meter. And they will alter it if you need something special. I expect a much better build than a generic eBay machine. And I did upgrade tube very easily. We'll see soon :) One thing is for sure, it isn't a $30K Epilog....... But I can buy a basement full of Chinese lasers for that price.

[Jeff Body]

Just sent you a PM John

Definitely keep me update on your laser purchase.

[Joseph Shawa]

SPT make some great tubes as well and their power supply is better than EFR.
Anyone one a 150-180 Watt EFR Power Supply?

How do you figure that not using it causes it to go bad? Really would like an explanation of that one as obviously they don't get used after testing at the factory. Then they only are usually rated for less that 10K hours but usually last longer.

It is usually too high of current that kills them early.

[Joseph Shawa]

My 150- 180 Watt Tube was powered by the matching power supply from EFR and using their "Rated Power" the tube was getting 34-36mA. 100% was putting out 38 mA!

I set the power Max on the machine itself to about 75% to get 28mA
Turn the power down and extend the life of your tube.