The Boeing Company

Larry E Dolan

Gary E Georgeson

Stephen Christensen

David S Nansen

Donald K Dabelstein

John Lars Eickelberg

Blake E Reed

Kirk A Reinkens

Ron N Scarborough

John L Eickelberg

Thermoplastic welding is an emerging technology targeted at significantly reducing the manufacturing cost of aerospace structure by eliminating fasteners and the touch labor associated with fasteners to prepare, install, and inspect the assemblies. Quality welds are highly dependent upon achieving appropriate temperatures everywhere along the bond line. The present invention is a system that evaluates the quality of the welds involving inputting an EM pulse to the embedded susceptor and listening to the acoustic response that the pulse generates to determine weld quality from the sound.

Thermoplastic rewelding process

A static coil induction welding apparatus and method for induction welding thermoplastic composite structures. The apparatus includes a plurality of independent coil segments disposed adjacent one another in side-by-side fashion to form a coil pack. A plurality of such coil packs are disposed in side-by-side fashion to form a coil assembly which covers the entire area of the weld zone. An AC power supply associated with each coil pack applies an AC signal through a switching network to electrically energize its associated coil segments such that the AC signals are in predetermined phase relationships relative to one another, thus generating a plurality of eddy current loops in a susceptor placed between the components being welded. The switching network alternately switches the coil segments such that the AC signals applied to the coil segments are shifted back and forth between adjacently disposed coil segments repeatedly approximately every 0.5 seconds. This produces a back and forth lateral shifting of the induced eddy current loops by about one-half the width of one current loop to provide uniform heating of the susceptor. It also eliminates various drawbacks associated with dynamic coil induction welding systems, allows feedback control over the power applied to each coil pack, and produces welds of even more consistent and higher quality than can be achieved with previously developed dynamic coil systems.

Static coil apparatus and method for welding thermoplastic composite structures

Tube forming on an end fitting

An electromagnetic coil configuration used for swaging small tubing. The coil consists of a coaxial arrangement of an inner helical coil and an outer coil shaped as a hollow cylinder with one end open and the other end closed and connected by direct electrical contact to one end of the inner coil.

Coaxial electromagnetic swage coil

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Renton, WA, United States of America

Larry E Dolan