[Miron.Costin]

Dear friends ,

Can you tell me wich is the diference between a lens with the focal lengh 63.5 and a lens with FL 127

Why are different FL ?
Does FL determin the best choice in cutting a specific material ??

Please help me undestand this difference between lenses

Regards ,

Costin

[abyss]

Lens with FL 63.5mm on 60W CO2 Chinese laser: engraving most popular materials, moderate "hot spot" size, moderate energy density, moderate DOF (depth of focus). Cutting some materials as thin acrylic, wood etc 2-5mm.
Lens with FL 127mm on 60W CO2 Chinese laser: probably not really usable due relative low energy density. Very wide DOF, but will have limited effect on most materials. Maybe can be used to engrave on extremely uneven surfaces - as for example bark/cork with strong texture. You can try to cut thicker (2-3cm?) some foam-type materials, but can't guarantee effect - as depend strongly from material itself and setup. I suppose will work well on 100-150W laser - for cutting effectively very thick materials as few centimeters foams. Maybe other thicker materials as well.