LASER FOCUS

[CNCMANIAC]

Hi,
I try to get a very thin focus point and even at 55mm. I can't get better than 0.5mm wide line.
I mean when I move the machine with the laser on...

I did test from 50mm to 60mm making line every 0.1mm so I did 100 lines
I also test with different power and speed and the line still stay
from 0.5 to 1mm wide...

Do you know how to get better than this?
J-P

[Tech_Marco]

Let me get some help from "MASTER Rick". If possible, please send me some pictures and I'll forward to the Master

[rick737]

Hi,
I try to get a very thin focus point and even at 55mm. I can't get better than 0.5mm wide line.
I mean when I move the machine with the laser on...
J-P

Hi, the usual lens is plano-convex it can give a 0,3 to 0,5mm spot, it may vary depending on several factors: tube, mirrors alignment ( a smal portion of the beam may be reaching the inner wall of the lens head and being reflected at an angle, this can cause a double spot ) so, check it carefuly.

If you want thinner than that you must get a :
Meniscus Lenses
Meniscus lenses are designed to minimize spherical aberration producing a minimum focal spot size for incoming collimated light.
or a
Aspheric lenses
Aspheric lenses are designed to be diffraction limited. They usually achieve a smaller spot size than both the plano-convex and positive meniscus lens. This provides the highest power density at the lens workpiece with equivalent focal length.

Rick

[CNCMANIAC]

Thank you for the reply,
As you suggest other lens to get a thinner focus can you point me somes places to get it?

Thanks again,
J-P