After about 150 hours of cutting my tube is going die, 18mA,

After about 150 hours of cutting my tube is going die, 18mA, (100mm/min) on meter and I`m not able to cut any ply wood any more. i can only cut acrylic sheet 3mm with 150mm/min.
Done all alignment, clean up mirrors, lens and no succes
I notice discharge is not strong like was before.
Any one have simmilar problem?

How old is the tube

At 18mA you’re overdriving the tube and shortening its lifespan. 16mA max. Personally I never go past 13-14mA. I cut 1/8" wood at 10-11mA 300mm/min easy.

Two years now

Laser tubes have a limited shelf life and Leak their gasses out with time,my last tube made it to 600 hours and 18 months before losing power over 3 days,somebody needs to collect data on life spans of China tubes to see the average time etc that they die at

This is what i suspect,gas just gone