amada fom2 mode shot

[Co2_Marcus]

hi.
can anyone say what mirror in resonator cause the sharp peak in the center.
Fanuc C4000i-B resonator.
beam mode taken at 5 meter mark.

hot mode looks good but has a sharp peak in the center. maybe 6-7mm long.
cold mode does not have this long peak.

the problem that started is that cutting with some conditions that uses full 4000watt
doesnt seem to cut trough anymore. same conditions was great a few months back on same steel.
but if cutting on lower power (3000) and slower it works.

 

[LASERNINJA]

The quick answer is output coupler ( mostly).

I agree though, That does look pretty good. I shoot them a little different. I take out mirror #5 and put the block about 2 meters from the #5 mount.

Do you know what your calibration coefficient is?

 

[Co2_Marcus]

calibration coefficient varies between 1025-1050.

found a reference shot that came with the machine dated "fanuc 2011". and it also has a small peak in center, so I'm not sure if its allowed.
some fanuc documentation says it should be flat.

bought the machine 4 months ago.
machine is 2012 model and has 31000 hours. turbo was changed at around 25000 without changing mirrors.
not sure if mirrors have been changed at all between 6400h to 31000h.
and no information on how often they cleaned mirrors, for sure no cleaning has been made after turbo replacement.

trying to figure out if that could be the reason for the cuts using full power isn't working so well.
and if i should change mirrors or just try to clean them.
and at some point i was wondering if i will be needing a power meter before i start messing around with the mirrors.

 

[LASERNINJA]

The most time I'd put on a set of internal mirrors is 12,000 hours. I usually clean them at 6,000.

It think it's a good idea to replace the mirrors.

 

[LASERNINJA]

I think what you are seeing with high power cuts is caused by a contamination of some kind on the internal mirrors.

From my experience, if there is a oil haze or dust on the output coupler, The more power you put through the mirror, the more heat it absorbs instead of transmitting the energy. My theory is that the optic expands or distorts from the heat and changes the focus. That's why we do a hot and cold mode.

You can compensate for this by reducing power, like you did, but also my moving the focus in the cut condition.

 

[Co2_Marcus]

Now I am preparing for resonator service.
ordered and received all internal mirrors, output coupler and rear mirror for the resonator
and power meter probe for the calibration after.

now trying to figure out how to change mirrors.
Fanuc manual says.
leak check, discharge aging, alignment.

but I have some Amada instructions mentioning low power aging and high power aging.
low power probably the normal manual aging.

my questions maybe then.
1. how many aging cycles to perform.
2. do I have to do high power aging. and how many cycles.
3. should I perform temporary alignment of FM4 between low and high power aging.
4. can I change all mirrors at once and thereby skip multiple purge/aging/leak tests. or should I change 2-3 at a time and repeat.


what procedure do you recommend when changing all mirrors?