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Another useful glossary is the CAD CAM and Nesting glossary.
Fly cutting, also known as grid cutting is a process used with laser machines. Traditionally, an array of holes would be cut one at a time e.g. top, right side, bottom and then left, before moving onto the next hole. This is a slow process, as the laser has to stop when changing axes. Fly cutting will 'snake' across the array of holes, firstly cutting all of the top areas before moving onto the bottom areas of the first holes in the array.