Hello every body, sorry for bothering you again.

Hello every body, sorry for bothering you again.
My K40 suddenly has what I believe is a loss of power, i used to cut my wood veneer at 14-20% of the power but ‘til few days, it’s not enough anymore …
I didn’t touch anything that would explain this sudden change but 1 week ago i noticed that sometimes the laser didn’t cut the same power all over my drawin’ (not sure to be really clear sorry)
I mean that it cuts some parts but not every, just like if the power was lower…

If I want to cut out my dedsigns, i have to increase the power from 14% to at least 20% but then the cut isn’t neat anymore.

I saw that a power loss could be caused by an old water so i changed it but it still doesn’t cut with the usual power …

Do you have any idea ?
Sorry for my potentially bad english
Thank you :3

Clean the mirrors and check alignment.

How old is your tube and how hard do you run it?
Do you have digital panel? i.e. can you read tube current?

I already clean the mirrors and the alignment is almost correct (could be a gap of 1-2mm between the top right and bottom right corner… maybe that’s enough to create the loss ?)
Bought my K40 in September so it’s not that old, what do you mean by ‘how hard do i run it ?’
I choose my power with a +10 +1 +0.1 or -10 etc button, is that what you call digital panel ? I’m not really informed about the machine :slight_smile:

When you do your alignment do you check all three mirrors? Do you have an air assist nozzle and if so is the beam exiting head in the center of the nozzle? When you check the alignment on the first mirror do you get a single spot or a doughnut shape?

Do not forget to clean focal lens ,and bump goes up

Just checked, the alignment is almost perfect, all mirror are clean, cleaned lense yesterday, changed the water too but i still have this problem, i dont understand why i need 2-3% power more than usual :slight_smile: i have no air assist, the dot made during the alignment are round but i need to press the laser test button longer than i used to

Check fan is spinning on laser pwr supply

@Phillip_Conroy How do i check that ? I’m a noob xD

Differences in material can cause changes in settings.

@HalfNormal Yeah I know, but it’s been like 6 mounths since I cut my veneer with the laser and I’m now used to select the best cutting power for each wood/veneer, but since 1 week, those parameters seems not to be enough anymore

Trying all the easy solutions before the ones that cost money! :wink:

@Manon_Joliton from all indications it goes without saying that the power available at the surface is less than it used to be:

These are potential and typical causes of weak power assuming you are using the same materials as previous jobs that worked:

  1. Changes in power settings from panel or software
  2. Poor alignment
  3. Improper focus
  4. The tube is wearing out (tubes power decrease with time and use)
  5. The LPS is going bad

Seems you have eliminated 1 & 2.
Do a ramp test for #3.
Since your machine does not have a laser current meter its not possible to know how much current is being used.
If the current is low then I would suspect the LPS.
If the current was high but still lower in power I would suspect the tube.

Kinda flying in the blind without a laser current meter.

Thanks for all these informations, how do I check the focuse ?
I also just noticed that while cutting at a higher power (30-40%), a 5mm strip is burnt above the cutting line (see the pic) it’s not caused by a litlle flame maybe this coud help finding whats going on :slight_smile:
Do you think i sholdn’t use my laser 'til we find out where the problem is from ?

Do a “ramp” test. Search forum for instructions.
Looks like you have a reflection likely in the head. See @Nedman question as to alignment through the head.
Post pictures of beam spots on mirrors and through the head. By beam spots I mean whatever you use to see spot position on mirror and bed.

@Manon_Joliton Hi, if you are getting a double line at high power surely you have a reflection, double check mirror aligment, and get sure the beam is centered when reach the head hole. I had same problem some time ago, and a good aligment solves it.

@syknarf ok i’m gonna check again. Do all the dots need to be in the center of each mirror or is it just for the hole of the laser head ?
(Yesterday i just made sure that the dots ‘stacked’ when the mirror is close and when it’s further)

@Manon_Joliton align the dots as close to the center as you can. Especially on the head and the lens. If beam reaches the head close to the borders, the risk of a reflection on the interior of the head is increased, and double beams can be created, also this decreases the cut power.

Thank y’all guys, did the alignement again and cleaned the inside of the laser head and the lense and it seems to work back, thank you all for your help :raised_hand:

I’m having this same problem. I’ve replaced the pot, the LSU, and just now the tube. I’ve spent hours aligning and cleaning all the mirrors and focus lens.

I’m at a loss