Process Date: October 2002

A Firestar f100 laser with a linearly polarized beam was used to cut these 0.025” mild steel samples.  The cuts were optimized in the direction of polarization at 130ipm using 100W and 40psi O2 assist gas (upper picture).  A positive meniscus focusing lens generating a 0.004” spot was used for beam delivery.  These cutting conditions were then applied to make the circular cut in the bottom picture.  Cuts in the direction of polarization (horizontally) provided clean burr free cuts, cuts away from the polarization direction (vertically) provided cuts with a burr.  Heat affected zones, on right and left sides of the circle, corresponds to the amount of burr adhesion on the back of the cut edge.  Using a quarter-wave plate or phase retardation reflector, the linearly polarized beam can be changed to a circularly polarized beam.  This beam delivery setup allows for even cutting characteristics in all directions.

Edge  view of 0.025" mild steel cut using a Firestar f100 laser at a speed of 130ipm with 40psi O2 assist gas.