K40 internal mirror problem?

Can you show us a picture of what you are describing?

How are you safely looking at the internal mirror when it’s firing??

top is 10% power for 1 sec
bottom is 99% 1 sec
right out of the tube, beam hasn’t hit the mirror yet

internal mirror not firing

internal mirror while firing

With the tube compartment opened and ppe using an iPhone XR

Hello. I think you have the same problem as i have. The tube. When the power is at around 13% it does an oval mark. If i rase at around 40% it split the beam.

I see what you mean when you say your beam is split. Mine is coming out hollow for the most part. Slightly different issue but maybe they have some of the same root causes. Have you found a solution to it yet or still looking?

Solution is a new tube. This one dont have more that 50 hours but because of covid i didnt use the laser for more than 2 months so i cannot ask about any warranty. The problem in my case i think are the inside mirrors from laser. In your case i think the tube has gone TEM01 mode. Something like this:


You can find other examples of discussion here about TEM01 mode that might be helpful for confirming the diagnosis:


Here’s a recent example:

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Thank you all for the assistance and helping to diagnose the issue. I went ahead and ordered a new 45W from lightobject last night out of frustration.
Glad I did.
Are there any other reputable sellers out there who you like to purchase from that don’t sell cheap tubes such as the one I previously purchased.
This tube had under 10 hours on it before it went all squirrely on me.

You might already know all this, but just in case, or for the next visitor who finds this page while searching for more information, a laser tube can be destroyed very quickly by insufficient cooling.

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Did the tube get overtemped?

absolutely great information. I am incredibly attention driven keeping the water temp within its safe workable range each and every time I operate the machine.

the new light object tube is a dream compared to what I was warring with on that TEM01 business. Thank you again for all of the insight and being a huge help in getting my system back up and running. Keeping an even more(if that possible) critical eye on temperature just to be safe and make sure this tube last a very long time.


Dont “keep and eye on it” rather add a water sensor interlock so there is no possibly of damage.

You are lucky because in US you have a lot of options for spare parts. In eastern Europe i stick to Cloudray from Aliexpress. I already ordered from them. The option from Lightobject would cost me the shipping more than the tube itself.

I’m positive the tube was bad on arrival, however the new CW-5200 should nip all heat issues right in the butt and keep me cutting at a steady temp :slight_smile:
Gents thank you for the assistance.

How will the CW-5200 shut down the laser in the case of an overtemp?

I don’t leave my laser when cutting so I am continuously monitoring the temps as well as water flow and the job in process, so that shouldn’t be a problem. However a flow alarm and over temp alarm will assist in making sure all is working within safe limits.

Doesn’t sound like it would be quite worth it to pay that much in shipping. But at least you’ve found a solution that works for you.