Metal honeycomb welding apparatus and method

Abstract

Welding apparatus for making metal honeycomb core panels by welding together preformed corrugated metal strips is disclosed. The assembled portion of the core panel is positioned by vertical finger electrodes on a horizontal base with the core panel workpiece end located along the line of a welding station extending across the base. The finger electrodes are arranged in two rows extending parallel to the welding station line, one row being insertable into the honeycomb core from above and the other being insertable into the core from below, each row also being movable from a first workpiece engaging position to a second welding position with one edge thereof along a welding station line. Welding heads, each including a welding element, are movable to and from the welding station. A corrugated metal strip is detachably held onto and carried to the welding station by the welding heads. The strip is positioned at the welding station with its outer apices and those apices on the workpiece end of the core panel engaging each other at nodes along the welding station line. The welding elements are elongated members having edge faces, the profiles of which register with the strip inner apices when advanced to the welding station. The welding elements are particularly useful with strips formed with tit-like projection arrays on their edge faces. These projection arrays make up the points of engagement between the welding elements and the finger electrodes, across the honeycomb nodes. The welding element longitudinal edge faces force the rearwardly-directed apices of the strip into contact with the forwardly-directed apices of the assembled honeycomb core forming a node so that welding current passes between each welding element and finger electrode through all the projections of one array. A weld joint made up of multiple spot welds, each of which is formed about one projection, is formed simultaneously between each mutually engaging pair of core panel and strip apices. One, two, or more such weld joints may be formed simultaneously, depending upon the number of welding elements. The welding elements thereafter can be retracted, moved parallel to the welding station line, and advanced to form welds at other nodes along the welding station line. When all desired welds are completed along the welding station line, the welding station positioned row of finger electrodes is withdrawn from the honeycomb core, the core advanced by moving the workpiece engaging positioned row of finger electrodes into the welding station position and emplacing the other row into the workpiece engaging position. The welding cycle is then repeated.