Abstract: A self-limiting method and apparatus for deburring or rounding sharp edges. Structures which basically comprise a skin which is a surface of revolution with a plurality of upstanding ribs in a pattern forming pockets often have sharp edges on the sides of the ribs, formed by chemical milling or machining operations, with the edges lying along lines substantially parallel to the skin. It is necessary to deburr or round over these sharp edges without damaging or deforming the ribs or skin. To accomplish this, the structure is mounted on a fixture which permits the structure to be rotated around its axis of rotation while the axis is tilted at selected angles. The fixture is positioned above a hopper containing hard, small balls (usually steel). An elevator mechanism lifts the balls to a dispenser above the fixture which has appropriately located slots above the sharp edges to be rounded. Balls are allowed to fall through the slots onto the sharp edges and adjacent areas.

Abstract: The invention is directed to the power control of a gas laser being moved by a prime mover along at least two different axes at various speeds to provide effectively constant output power to the workpiece surface. Signals from the prime mover axis representative of the speed of movement of each axis are separately rectified then summed and modulated with a positively offset triangular wave signal. The resulting output signal is a composite width modulated square wave pulse representative of the instantaneous laser output power required to maintain an effective constant power to the workpiece at various speeds and directions of movement of the laser.

Abstract: A method for etching patterns on the interior surface of narrow metal tubes. A thin tube having a narrow internal diameter is dipped into a maskant solution to a depth equal to the distance from the tube end etching is to be stopped. A thixotropic maskant having high edge thickness along the dipped edge is required. The shaft is removed from the maskant and dried. Plural dips to increase maskant thickness may be used, if desired. Both ends of the tube may be dipped to localize the area to be etched away from both ends. The tube is placed in an etching solution which is agitated and replenished as desired. After a suitable period, the tube is removed from the etchant, rinsed, dried and the maskant peeled away. A sharp, even, etched edge results, with a smooth fillet and no leaks of etchant through the maskant.

Abstract: A structural panel having superior insulating properties which comprises a sheet of polyimide foam material having a metal layer on at least one surface, the metal layer being diffused into the foam structure, providing a superior metal-to-foam bond. The polyimide foam has excellent insulating and structural properties and is highly resistant to high temperatures and open flames. The metal layer adds considerable structural strength, since the diffusion of metal into the foam produces a three-dimensional metal structure rather than the usual planar surface film. The metal layer is applied to the foam sheet by chemical vapor deposition under conditions which improve the diffusion of the metal into the foam.