Doesn’t hurt to ask again but I’d already asked about making sure to check the lens. Wouldn’t be the first time recommendations were ignored and days passed only to find out steps were skipped because ‘it didn’t seem important’.
The strange thing about this issue is the OP says nothing in the software or design changed since a few months ago it would cut fine with 3 passes but now it blasts through the same plywood in 1 pass with charring. Even odder is there seems to be laser power control.
Something is not right in Denmark…
The bed has been modified so the height is adjustable and I use a stepped tool to measure from work to bottom of lens to focus depending on thickness of material
Laser hood has extractor mounted on it for extra extraction
You might get less charring if you focus to the middle of the material instead of on the top surface. On second thought, with a top surface focus, the out of focus beam would be below the top surface so more of the charring would be on the backside.
How did you measure the TEM and can you post a pic of what you saw?
BTW, you never did tell us that you saw the power output changing with the changing voltage on LPS-IN. You should be able to raise the power level from 0% until it starts marking, raise it .5V draw another mark, +.5V mark, etc upto max power. You should not need the software for that as it can all be done manually.
Please write the display power percentage setting for each mark.
You can not determine the TEM when you burn a hole. And I’m wondering if you are reading what we are saying in the messages because your pictures show you are seriously over driving your tube at anything over 40% on the display and we’ve shown, told and pointed you to material which states this. It looks like your marks are nearly all the same around 30% power, does it not? And that was a really poor choice of material to see/show variations in power levels. A wood with a consistent color and texture would have been an appropriate choice for that test.
To display the TEM you need to turn the tube power down so you are marking the paper, not burning it. And look at the chart @jkwilborn posted showing that a ~700mm long CO2 tube’s max current setting should be roughly 15mA and never over 20mA(40W 800mm tube ).
I’m just really surprised that you never questioned or mentioned the things posted which went counter to what you were seeing and doing.
I do not know what you’d changed or what has changed but you are asking the laser to put out full power, or nearly full power, at 30% on the digital display so if it cuts in one pass cool. If it’s burning the edges then turn down the power, increase the speed and cut in multiple passes.
Clearly I am not the only one who either does not read or does not understand what has previously been said, as you can see from my original post I was cutting on 30% with 2 passes now without changing the settings it cuts on the first pass and burns and even if I change the power anywhere 10-80% it’s the same
Like testing tem , under 10% doesn’t fire and anything else burns
You may of not taken into account that I may not be as intellectual as you and that’s why I was asking for assistance
Your LPS has failed, replace it.
Going forward, when you’re asked to do something and something in the process of following the instructions does not work as required say something.
TEM instructions don’t say to burn a hole… You should have said your machine wouldn’t let you lightly mark the paper.
You also left out the fact that not only does the machine now burn at full power in one pass when set to 30% it also burns at full power at all settings.
You bought a cheap laser cutter, for your own safety and enjoyment of the machine, read all the FAQs you can find on how the K40 operates, are made safer and how they will last longer. It is NOT anything like a toaster oven, it requires knowledge and understanding of CO2 laser operations.
I think you clearly didn’t read the original post , please read the above and tell me where I missed out saying it burnt on ANY power , yes that includes 30% And yes that means it will burn on a TEM test
I clearly did misunderstand one thing and that was that you would be helpful and not condescending
