Onomy's Giant Lasercutter
When embarking on the Liberty Science Center work, we discovered that our projects' need for large pieces of precisely-cut sheet plastic put us outside the sweet spot for commercially available lasercutting machinery. Low-power laser cutters tend to use CO2 lasers under 100W and limit the bed size to 2' x 3' in order to accommodate the CO2 laser beam's dissipation behavior. Larger laser cutters are available, but they tend to have much higher power lasers for doing, say, sheet metal fabrication. It was going to be financially implausible for Onomy to get enough beam time on a laser cutter of this larger sort.
Onomy constructed its own low-power, large bed lasercutter. We purchased many of the components from Emissions Technology, including the 75W laser and an initial optical component where we substituted a long focal-length mirror/lens for the typical planar mirror to achieve an adequate form of collimnation of the laser's beam over the entire bed of our machine. Localized smoke extraction with a carriage-borne suction system serves well to vent the fumes from cutting.