Process Date: December 1999


Cut with a Synrad 200 watt laser at a speed of 2"/minute.

8"-thick foam was cut with a Synrad 200 watt laser. The cut edges on this depth of cut are remarkably square, considering that a lens with an 8" depth of focus was not used to cut the material! The foam appears to offer some self-regulation of the beam focus profile. Rather than producing an angled cut edge that mirrors the convergence and divergence of the beam profile, the resulting cut is narrow and almost parallel throughout its depth. The edge quality, in this case, appears to be somewhat independent of the position of focus, possibly due to the waveguiding effect, which occurs when the beam is reflected at the side of the cut walls, rather than being absorbed. A diffuse gas assist was used to prevent discoloration of the edge.

A sealed CO₂ laser cuts styrofoam equally well. The low-density nature of this material allows thick sections to be cut with only tens of watts. To achieve the best possible edge quality, little to no gas assist pressure should be used during the cutting process.

For most foam materials, a large thickness can be cut with a relatively short focal length optic.