I am cutting some 3/8" acrylic with beautiful results until the very last second. I have the acrylic standing off the bed by about an inch to prevent flash back on the backside from my honeycomb bed. When the cut finishes, the acrylic drops. The problem is the laser is still on for a split second after it stops moving (charging down I assume), when the part drops it falls out of focus and a large blister is left on the surface of the acrylic that dropped where the out of focus beam has hit the surface. I need to stop this from happening. Surely I'm not the only one that has seen this. Ideas?