Patent ID: 8212177

Claim:
A variable focus laser machining system configured to ablate a surface of a work piece, comprising: a laser emitter configured to emit a laser beam; a focusing element configured to focus the laser beam; and a controller configured to: focus the laser beam at a first focal point on the surface to ablate material from a first machining surface to a second machining surface, the ablation of material resulting in partially ablated material being retained on the work piece, the first focal point being approximately positioned on the first machining surface; determine that the first machining surface has moved relative to the first focal point; determine a location of a second focal point based on the location of the first machining surface and the second machining surface; re-focus the laser beam at a second focal point to ablate the partially ablated material; and re-focus the laser beam at a third focal point approximately positioned on the second machining surface.