LaserUser.com Forum (formerly RDWorksLab)

Post by Gene Uselman » Sun Aug 28, 2016 8:15 am

#1. Glass tubes are very inexpensive compared to domestic [USA] tubes- so... there will be trade-offs

#2. It is important to know what your max current should be. This may be exceeded but there will be a trade-off on the life span. If you can find the mfrs site- it should be called out. The max current allowed may be limited on the High Voltage power supply- at power settings above the limitations power will be flat. If your machine does not have a Milli-amp meter, you should consider adding one. Here is a link to Hytech2K's nice article on adding one to his machine- it is not difficult electrically BTW:
http://rdworkslab.com/viewtopic.php?p=1654

#3. Glass tubes are usually rated at the max power it can produce- safe max power will be less. Make allowances for this fact of life in the Chinese laser world.

#4. These tubes are sensitive to heat- if they are not cooled properly, life will be short. They can be cooled in a variety of ways- from a 5000 (and up) series chiller which is actually a refrigeration unit, to a 3000 series cooler which is a tank with a radiator and fan, to a fish tank circulation pump in a tub of water. What you need will be determined by the ambient temp, the duty cycle you expect and the life you expect. What ever you use the cooling water must be kept clean and I would not use tap water. You should have some way of monitoring the temp, of course.


#5. Shelf life of a Glass Laser tube is approximately 12000 hours. Much like a carbon battery, they deteriorate over time.

#6. Actual Wattage will vary as the beam encounters mirrors [3] and the lens and can be measured at each place with a [fairly expensive] power meter or with Russ' Dandy Lollypop [forget what he calls it] at a more reasonable price. A combining lens to add a visible dot to the laser path will also cost a bit of power.

Some of the more respected Chinese tube makers have important details on their sites:

EFR- [tubes, power-supplies and lenses] http://en.bjefr.com/
Reci- [tubes, power-supplies and mirrors] http://www.recilaser.com/en/index.htm
If you see errors or would like to submit additions, please PM me. Thanks Gene

A shelf life of 12,000 hours is 16.5 months.

I’ve unpacked an 8 year old new-in-box screw-adjust CO2 tube and it worked fine - still is, 5 years on.

That’s 113,000 hours so far and the last time I measured it (3 years ago) it was still putting out in excess of 90W.

So 70,000 hours on the shelf and about 10,000 operating hours with 33,000 ‘shelf’ hours and still going strong says to me your calculation is missing some digits.

Shelf life here is based upon the manufacturers spec. 8 hr/ day use , 52 weeks a year, for 5 years.
Glass tube loose their gas charge over time due the permeability of the sealant used. Toward end of life it takes more and more power to create the same output and eventually there is not enough gas to create the output.

There is a difference in the quality of tubes too. A five year old Reci tube may still have life in it while a No-Name, maybe, maybe not. Tubes are one of the few things in the Chicom laser world where a brand name can rise above the average. Of course, they are then counterfeited.

Quality manufacturers and resellers will usually rate the laser power at the max safe power, IE 80 or 90Watts instead of the Max max that the tube will put out. For instance, Automation Tech Laser sells Shenhui lasers and in the spec sheet for their 90W Reci tube they state: Laser Power: 90W, Min 80W, Max 100W That is honest advertising and I found it impressive. People trying to get a fast buck from their machines would normally advertise as 100W. I measured the power at just over 100W BTW

Another overview of laser power vs. length and diameter and working current.

I got an EFR F2 80 watt, now..their site gives details and usage recommendations, 80watts- max 95, mA to run at max and under etc.. and as said above, using it under recommended and keeping it cool to a degree does prolong life for sure, my first machine was a k40, no name brand everything, and I installed a flow meter/temp has days used showing not hours, but i have 98 days on the meter running, over 2 year period and installed a little while after getting the machine,never ran it hard, 18mA max in beginning, kept below 15-16mA and below most of the time, ,and the tube is getting weak but actually still runs today..so care and cool ( 18C)does work..ordered my new machine and now ordered another flow/temp meter and will be first mod I do..was $22.00 2 years ago now $41.00 , cheap protection in my mind,,was worth it for a cheap no name k40,,so any new decent machine is alot more than one of those...lol...so worth the time to install and its cost..(installed on water return, so water leaving machine temp not into machine ..)and a mA if one not on your machine..both a must have for me..