I need your knowledge concerning lenses, …
I’m making engraving laser on granite stone. My first laser broke down and was really hold so no more motherboard pieces was able and i had to change it. The laser was from vytek and i used a 18mm dia. lense with a F38.1mm and i got great and detailed result.
The new laser i bought use a Dia.25 F38.1mm. and the result is not that good as the previous laser. It’s lacking of detailed and the spot size seems bigger than the previous laser head.
All of this for this question: Is the diameter of the lense affect the spot size and the precision of the engraving ?
PS: the laser machine seems really precise as i make a second engraving on the same stone there is no gap. It engraves at the exact same position. So i guess the mecanism is really precise.
I haven’t tried granite but slate, I assume granite is harder. Glass should be roughly comparable. Here, my experience is that the laser beam almost explodes the surface with a slightly larger dot as with softer materials, as a result. I use a 50.8 (2") lens on my CO2 laser.
If you have been able to produce smaller dots with the same lens type, you should be able to do it with the new machine as well, unless your new laser tube produces a larger output spot or the focus is not 100% ok.
On my diode laser, engraving in stone from the beach has destroyed a lens, small fragments simply spray from the stone in all directions and I did not use enough compressed air.
Yes granite is harder and laser beam explodes the surface. That’s why i think the smaller spot we get the better result we get cause it explodes less surfaces.
I’ve tried many focus lenght and the best result i can get is way far from our previous laser. The laser tubes can produce a larger output spot ? It doesnt only the lense that matter for the spot beam size ?
The output beam from laser tubes varies in diameter, depending on the physical size of the tube and the energy effect, this is also one of the reasons that the lens diameter varies with the different sizes of laser machines. Roughly speaking, more power - bigger spot.
Why it is not possible to get the laser beam to focus to zero with optical lenses is something Russ Sadler has a nice explanation for. But in which of the many lovely videos he has made, I can’t remember unfortunately.
It is difficult to see how much difference there is in the dot size and or it is due to different contrasts.
What does it look like when you do a line spacing test?