Diode Damage from burned glass? PLE 3.5

[Frozenferrari]

Over the last two days I perhaps ran my 3.5W PLE Pro a little too hard. We were trying to cut some thicker stuff and engrave, and take some cool pictures. I kept a close eye on duty cycle and the laser never got uncomfortably hot to the touch. But I admit there were a few times where it was ran for maybe up to 3 minutes. I think I didnt allow it enough cool down between runs.
I even checked the surface of the unit near the apeture with an infared temp gun during the sessions, and never saw temps above 130F.

Anyway, I managed to scorch a rectangle into the dust window. Inside the laser looks good but hard to see. I was able to clean it off with a touch of rubbing alcohol and lens cloth... But even after, the shadow of the spot remains *actually a little clearer than the rest of the window* ..Is that bad?
I dont know what exact lens the unit has, or if this caused issues with anything from back reflection or would later if left as is. A few quick test runs including a 20 second run, everything checks out fine. Just not sure if maybe I handicapped the diode now :/ no LPM.

I reached out to Jet Lasers to see about the costs of repair. Im not very well off. But Im wondering if it's even worth getting repaired. Laser seems fine but I would be bummed to find out my diode fails sooner in life, or outputs less than it could be...


Thoughts? Perhaps JL used a window which would pail in durability to the rest of the unit? I deserve what I got..But I swear I dont think the laser reached temps that should do that by design... ?

Before Alcohol cleaning



After alcohol cleaning.

 

[AMooMooCow]

I'm not a doctor, at least not anymore, but it seems to me like the dirt was very basic and dissolved the coating off of the lens. In medieval times, you might use ash to wash your hands because it's a source of basic material, so it's good at dissolving things.

My guess is your lens was so close to burning wood that a super-heated gas of basic material deposited a thin film, mixing with your AR coating, dissolving into it, and was able to be washed away after

 

[ChrisWhit]

I have that same laser. That lens on yours doesn't look quite right to me. It looks kind of rough. Maybe that's from the cleaning ..? But the outer lens on mine has a smoother, thinner shape. And the glue work around the edges in those pics doesn't look like typical Jet Lasers build standards. Maybe that builder was having an off day....? I dunno

 

[hakzaw1]

Certainly worth trying to replace lens THEN read the power on a LPM..
I have posted this a dozen times..
Err on the side of harming by any means.
Cool down cycle needs to be as long as the duty and then some.
Stands to reason--
1)Cool to touch outside--inside cool
2)Warmish on outside--very warm inside.
3)Hot outside... overheating hot inside...
Ambient plays role-- JL tries to make best heat sink.risk
Going past #2 can be a risky thing for little purpose.

Mic the lens size
cheapie soldering pin w/ very sharp point and gently
chip away at the bits of glue you can see in your (great btw) pics

until you are sure you dont need other new parts.... just remove old lens (&n keep it BTW)
Contact at JL.org /Gray/laserforum member-- needs lens for Pro Pl-E 3.5W 465nm <is that correct??

invest in First Contact lens cleaning kit --spendy BUT once clean /keep it clean--I'd be carerful to protect w/ a clear AR lens in the very front. OR --I make my own lens caps w/ 1/4 inch hole covered w/ a glass diffraction grating from Gray. Forgetting to remove a black lens cover is not we want-- 3.5W-- in seconds a lens &/or cover will get smoked-- I can see if my laser is on but in 20 some beams-- the grate is glass--

We do have a few members here that are pros at getting lasers apart.
AFAIK-- He likes USPS/EMS for returns but DHL or other EXpress w/ insurance for stuff broken
going back to owner-- he may allow a split in ship cost-- you pay here JL pays DHL
you wont need to insure$$ a broken laser-- value is $20 on the forms- item is 'broken light for repair'
hopefully it wont come to that but no harm asking Gray for help--I cannot do as much these days as I would like-

I may be forced to sell some of my gently /hardly used JLs
PM me and keep this thread going...

get back w/ me before you send it to anyone at LPF to fix.

Hak

 

[Encap]

Wait for JetLAsers to reply about it---looks like you touched something rectangular with small inverted u shapes on the left and right in the center when using the laser and also less apparentlyat the 8 o'clock position on to the window that you were able to clean off along with the coating on the glass.

It is not a lens ---just a window of flat glass with an anti-reflective coating. Easy to replace.
Am certain JetLasers will send you a replacement you can attach/glue after removing the bad one.
If you don't want to do it yourself send it to JetLasers and they will do at no charge except shipping.

 

[hakzaw1]

yep thanks

encap
PMs from me blocked?

 

[Frozenferrari]

Thanks for the replies!

Yeah the laser is original from purchase and Ive been careful not to get anything closer than about 4” to the aperture. Those little specks in the photo are tiny specks of dust that fell from the lens cloth during cleaning. The window is pristine other than the remaining shadow of the rectangle and the odd semicircular imperfection to the 12oclock position in the second photo.

The glue job was actually like that fresh from the box from JL, surprisingly. I remember noting that at the time...

Agreed Hak on surface temp rule of thumb. Bad idea to go for another round if the laser is already warm. Mine never got hot, really, but very very warm would describe it well.

I think at this time Id just pay the shipping to get it repaired by JL themselves, since they know minutia I dont yet. Seems like an easy job, but if some sort of gas in the air threatened to ruin my laser, ill do my learning with a homebuild rather than a professionally made gem like the PLE.

Gray has already responded to me and acknowledged my request to organize repair.

Thanks all. Would love to read more of your thoughts on overheating AR coated glass and the resulting effects on the system.

Ive seen a few scientific studies of it but those seemed to focus more on the glass itself.