Method and apparatus for precision spin-welding

摘要

A spin-welding apparatus utilizing a servo motor assembly has a closed-loop control circuit for rotating one part of the workpiece being welded relative to the other. In use, the servo motor immediately rotates the first part up to a set speed at which welding will occur, and a power cylinder moves the first part into frictional contact with the second part. Contact between the two parts is observed by a microprocessor interrogating a signal from the servo output corresponding to an increase in the load on the servo motor due to frictional drag between the parts, with "contact" being identified as surpassing a predetermined threshold error or variance value between the closed-loop system's input and output values. The microprocessor then counts a predetermined number of revolutions, and terminates rotation of the servo motor and first part. For accurate radial alignment between the parts, rotation may continue past the predetermined number of revolutions that fraction of a revolution necessary to achieve proper alignment or orientation.