Question on loss of laser power with K40

[clmartin0721]

Hello,

My K40 laser seems to be losing power as my cutting session progresses. I am running at about 90% power, but even at a speed of 3 in moshi, I can't cut 1/8" Plexiglas (clear). Also, the longer I cut, the lower the laser output goes, eventually just barely etching the surface.

No strange sounds, and the motion control is fine, laser is firing, ect. Wondering if this is the tube and / or the power supply. I don't think this is a mirror or alignment issue since it degrades over time....if it was alignment or mirrors, the output would be low from the start.

I have quite a few commercial / lab power supplies around, and I was wondering if I could use one of those to test the PS. If so, what are the required specs of the power supply for the 40W laser?

Also, can the tubes be refilled, or do I just need to get a new one?

I would like to trouble shoot this BEFORE I start ordering parts...

Thanks for the assistance.

Craig

[Tech_Marco]

Craig:

When you do mirror/lens alignment setup, make sure you do it on four corners but not just on a specified location. You may do a simple test by doing a cutting on four different corners see if laser power is losing. That's the only way to test whether this is a test issue or alignment issue.
In most case, it is either the tube leaking gas or mirror alignment was not installed properly (the laser mirror, not the machine mirror). We have two similiar issue reported by two customers. So, we're going to test all our small tubes imported recently.

How old is the laser tube?

FYI, I found one of the best tube manufacturer in China for making small tube 700mm to 1000mm. I've just ordered 50x of those for next ocean shipment. It is a company famous for many laser manufacturer and price is just about $25 more. I think it is worth it. Forget about those tube on eBay as tube quality is a problem


Marco

[waltfl]

hi there
did you check the cooling water temperature? it should never go above 28 C (84F) and the current should never go above 18mA.
it sounds to me that your cooling water getting hot. you need to measure this with a digital thermometer right on the hose where it enters the machine housing. you also need to measure the current with a mA meter.
like marco said how old is your tube if it is more then 1 year old and you have used lots of 90% power it is probably the tube, it would not be the power supply.
greetings
waltfl

Hello,

My K40 laser seems to be losing power as my cutting session progresses. I am running at about 90% power, but even at a speed of 3 in moshi, I can't cut 1/8" Plexiglas (clear). Also, the longer I cut, the lower the laser output goes, eventually just barely etching the surface.

No strange sounds, and the motion control is fine, laser is firing, ect. Wondering if this is the tube and / or the power supply. I don't think this is a mirror or alignment issue since it degrades over time....if it was alignment or mirrors, the output would be low from the start.

I have quite a few commercial / lab power supplies around, and I was wondering if I could use one of those to test the PS. If so, what are the required specs of the power supply for the 40W laser?

Also, can the tubes be refilled, or do I just need to get a new one?

I would like to trouble shoot this BEFORE I start ordering parts...

Thanks for the assistance.

Craig

[clmartin0721]

Hello everyone

OK. The tube is about 14 months old, but it has been used very little, less than 8 hours total cutting (at least by me).

Also, the cooling water isn't getting too warm, but I don't have a thermometer on it and I will add that. The room ambient is about 73.

I will recheck alignment and post the results.

Cheers,

Craig

[Tech_Marco]

Usually a tube gained 3 months warranty from a manufacturer. Even the best seller "RECI" offer 6 months warranty only. In general, a regular tube won't laser longer than 2 yrs but some may do but will power lost. Just let you know that laser tube is not just usage dependence but affected by time as well. But there are tubes we have in stock for 3 yrs and still functioning good. So, I'm not saying that all tube 'must' die within 2 yrs.

Because of this, I don't stock tube for long but need to refill the inventory very often as I want to sell 'fresh' tube.

Marco

[clmartin0721]

Marco,

Yeah this tube is probably two years old if I factor in travel time and shelf time in china. When will the new tubes be in?

Craig

[Tech_Marco]

It will take about 2months as I need to get it consolidated with other product to ship through ocean shipment. But if you need one, I can ship it from China to you direct but the shipping cost is more expensive than the tube itself. I may consider to ship 5+5 through DHL though.

I still have other tube left and I decided to test each tube before ship to make sure no 'doa' when arrival.

Marco

[Tech_Marco]

Marco,

Yeah this tube is probably two years old if I factor in travel time and shelf time in china. When will the new tubes be in?

Craig

Craig:

Just let you know that I have 4 tube in stock (received through DHL).

Marco