K40 laser issue: two dots instead of one at every mirror

Hello, does anyone know why I am not getting a clean marking on my laser when aligning?
I cleaned already the 3 mirrors.

Sadly, your tube has probably shifted into TEM01

See other posts tagged #tem01 for more examples.

I read a few about that, so I can start to think that the tube is dead.
In the meantime I get a new one, can I still use it?

Yes you can still use your tube in a TEM01 mode, it’s just going to have a lower effective power output.

Ok, thanks
The quality of the engraving is compromised?
Do you know where I can buy a new one either in USA or Mexico?

From the K40 Intro at the top, you will find:

You’ll see several sources there. :slight_smile:


Do you recommend the Ten-high tube?

Do you recommend the Ten-high tube?

I’d go with the SPT if I had a K40. It’s generally considered a well-known and high-quality brand, and it costs less than the Ten-high.

I see that @NedMan opted for the SPT for his K40:

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Yes, I highly recommend the SPT tubes. I’ve been very happy with mine.

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Hello, with my brand new tube I am getting also this shape in the second mirror
What could it be?

I got the Ten-high because of the lead time and urgency I have. I am having the same shape out of the new tube. What could it be?

That’s crazy. What does it look like on the first mirror?

That was the first mirror.
It’s crazy. I decided to give it a try and WOW… cuts way way better that the original one.
Less power and passes needed. Actually it cuts at one pass and less power.
The original one needed 4 passes and more power to cut

If that’s the shape of the beam coming out of the tube then there is a problem with the tube. Sould be a solid dot. Unless the beam is hitting something else before it gets to the first mirror. Can you give us a picture first mirror and tube end in the tube enclosure?

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Reminds me to point something out: If you don’t yet have an analog ammeter, strongly suggest adding one. That’s what measures actual power flowing through the tube.

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