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Abstract

A direct in-process measurement of the bottom kerf width uses a hardware, vision, and software system which captures a direct image of this kerf, computes its average width over a prescribed length and presents the data for visual observation, automatic control, and/or recordkeeping. In addition, by expanding the system to a measurement of the width of the top of the kerf, the verticality of the kerf may also be determined. In the preferred embodiment, a laser-cutting head produces controlled width kerfs in a sheet of plywood according to a preprogrammed pattern. A video camera is mounted relative to the cutting head and is held by a positioning system that is programmed to follow behind the cutting process and directly over the kerf. The optics of the camera are adjusted to view through the kerf and are focused on the bottom of the kerf which is backlit by a subsurface lighting system mounted in the corners of the tub on which the dieboard is mounted. The camera sends a video signal to a monitor that shows a reverse shadow of the bottom of the open kerf. This video signal is also monitored by a data acquisition and analysis system that is programmed to capture an image at some specific locations or times. These images are then analyzed for average width, root mean square (rms) variation, location, and orientation and the system parameters are adjusted accordingly to correct any deficiencies found in the kerf width.

First Claim