G.Weike Laser
Profession Laser Manufacturer more than 15 Years.
44
Picture 5-22: Adjusting laser focus3
E) Focus setting principle: distance between cutting month and material
surface is A, it is called nozzle cutting height or punch height. Focus
position definition: distance between focus to material above surface, see
picture 5-23,B is the focus height. Focus position is above the surface
called positive focus, focus position is below the surface called negative
focus.
Picture 5-23: Adjusting laser focus4
5.6.2.2 Relationship illustration of focus position and cutting material and
cutting section
As shown in below form 5-2, when cutting different materials, the laser
cutting focus is at different position, it has effect on plate punching and cutting
section and focus position when cutting different material with differentthickness.
Name and focus position
Cutting material and cutting section features
Zero position: laser
focus position is on
above material surface
Used for cutting thin metal
Focus on the work piece above surface, above
cutting edge is smooth, below cutting edge is
not smooth
Positive focus:
laser focus is on
material surface
Used for cutting carbon steel and other
material
Focus on the work piece surface, so smooth
surface scope is bigger. Kerf is big than that on
zero focus. Gas flow is larger during cutting.
Punching time is longer than that on zero focus.
Negative focus: laser
focus is in material or on
below material surface
Used for cutting stainless steel, aluminum and
other material
When cutting stainless steel, it needs
HP
Nitrogen to protec
t cutting section. Kerf is
widened with the increase of the thickness of the
work piece
