Fine tuning engraving

Hi again!

I used to have a 40w Diode Laser, and yesterday received the K40.

On my first test, engraving MDF 3mm, I did at 20 mm/s at 10% power.

But the Diode one was much nicer:

This the diode one.

And this the K40 one.

ANy idea how to improve it?


Was the one done on the K40 raster engraved or vector engraved?

The K40 will need a lot faster travel speed than your diode. It has a lot more power and therefore can engrave or cut faster than you’re used to.


It is vector engraved.

I changed to 5% power and 20mm/s speed and it has improved. But not as clear and fine as the diode onem, but enough for now.

I have ordered a HoneyBee bed, so I will wait to it to arrive before fine tuning it even more.

Are doing raster or vector engraving?

Edit: neverminded

Yeah because of the higher power of the CO2 laser it’s harder to get a lighter vector engraved. Do you have the work piece at the focal point of the laser?

Yes, I think so. I could fine tune it a bit more, but until the new comes, I will not do more test. I have works pending!

Do you know about doing a ramp test for checking focus?

Yes, I did, thank you.


Diode lasers can genrally be focussed to a much smaller point than CO2 lasers. This is caused by the wavelength. Therefore you will probably not get as sharp engravings with the CO2 as you can get from the diode laser, but still pretty good.


For engraving (using an 80 W tube), I generally use speeds in the 2000-5000 mm/min range (i.e. 33-83 mms/sec). Note that a CO2 laser (especially DC-excitation types) does not perform very well at very low power levels, so you should generally go for as high speed as possible.


Excuse my ignorance, but how long of a lens is in the K40 types?

As a general rule you want the smallest dot size. I agree with most, move faster… For these to perform best all parts must work together including the dot size.

There is quite a difference going to a CO2. I suggest a few videos to assist. Check out RDWorks Learning Lab videos. I just picked one that was interesting. I have found them very informative.

Good luck, take care be happy…

Typically a 50mm focal length in the K40, but sometimes they come with something else if that’s what the manufacturer had on hand.

Yes the typical stock lens in a K40 has a focal length of 50.8mm. You can do a ramp test to determine the exact focal length of your lens.

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I believe mine’s coming with a 1.5". It’s not a K40. I’ve watched this board, but never have seen it discussed that I remember. Thanks…