For the curious, occasionally, the question of tube life for these low cost Lasers comes up.
The tube in mine was down to about half strength so I replaced it today after 350 (give or take a few) hours of cutting time.
It lost about 10% power a month ago and steadily dropped after that.
Almost all my use of the machine has been cutting 1/8 and 1/4 inch acrylic and some 1/4 inch poplar.
I doubt that there is 10 hours of engraving time on it.
I ordered a new 35 watt tube from Light Object for $236 including FedEx shipping.
It arrived in three days.
Replacing the tube took about 30 minutes and half that time was spent looking for my wire stripper and dragging the soldering station out to the shop.
Plugged the water tubes back on and tested the unit for alignment.
Oddly, the alignment was perfect.
This is probably the first time that I have ever moved the machine without having to tweak the mirrors a bit.
So now the laser cuts just like it did when new, about one inch every 7 seconds through 1/4 inch acrylic.
In the specifications that came with the tube is the recommendation that the amperage be kept to 18 milliwatts.
I have been running mine at 22 because that was what FSE had originally speced so I may have cut some time off the tube life.
They have backed down a bit since then.
The cutting speed at 18 mw seems to be about the same as at 22mw.
$235.00 divided by 350 hours comes out to 67 cents and hour.
So far, I have had no other maintenance expenses.