Thermoplastic rewelding process

• US 6,613,169 B2
• Filed: 04/28/1998
• Issued: 09/02/2003
• Est. Priority Date: 09/03/1996
• Status: Expired due to Term

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Dolan, Larry E., Georgeson, Gary E.
• Primary Examiner(s): Ball, Michael W.
• Assistant Examiner(s): Haran, John T.
• Application Number:
  US09/069,002
• Publication Number:
  US 20030127172A1
• Time in Patent Office: 1,953 Days
• Field of Search: 156/272.4, 156/273.7, 156/273.9, 156/274.8, 156/275.7, 156/309.6, 156/308.2, 156/324.4, 156/378, 156/379, 156/64, 735/79, 735/82, 735/83, 735/87, 735/88, 736/43
• US Class Current: 156/64
• CPC Class Codes: B29C 65/364 being a woven or non-woven fabric or being a mesh
• CPC Class Codes: B29C 65/3648 said strip being perforated
• CPC Class Codes: B29C 65/3676 being metallic
• CPC Class Codes: B29C 65/368 with a polymer coating
• CPC Class Codes: B29C 65/4815 Hot melt adhesives, e.g. thermoplastic adhesives
• CPC Class Codes: B29C 65/5057 positioned between the surfaces to be joined B29C65/5035 takes precedence
• CPC Class Codes: B29C 65/8292 by the use of ultrasonic, sonic or infrasonic waves
• CPC Class Codes: B29C 66/1122 Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/532 Joining single elements to the wall of tubular articles, hollow articles or bars
• CPC Class Codes: B29C 66/71 characterised by the composition of the plastics material of the parts to be joined welding bar compositions B29C65/125
• CPC Class Codes: B29C 66/721 Fibre-reinforced materials B29C66/729 takes precedence
• CPC Class Codes: B29C 66/7212 characterised by the composition of the fibres
• CPC Class Codes: B29C 66/72141 Fibres of continuous length
• CPC Class Codes: B29C 66/72143 Fibres of discontinuous lengths
• CPC Class Codes: B29C 66/73921 characterised by the materials of both parts being thermoplastics
• CPC Class Codes: B29C 66/836 Moving relative to and tangentially to the parts to be joined, e.g. transversely to the displacement of the parts to be joined, e.g. using a X-Y table B29C66/65 takes precedence
• CPC Class Codes: B29K 2071/00 Use of polyethers , e.g. PEEK, i.e. polyether-etherketone or PEK, i.e. polyetherketone or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2079/085 Thermoplastic polyimides, e.g. polyesterimides, PEI, i.e. polyetherimides, or polyamideimides; Derivatives thereof
• CPC Class Codes: B29K 2307/04 Carbon
• CPC Class Codes: B29K 2309/08 Glass
• CPC Class Codes: B29L 2031/3085 : Wings
• CPC Class Codes: G01N 2291/0231 : Composite or layered materials
• CPC Class Codes: G01N 2291/0251 : Solidification, icing, curing composites, polymerisation
• CPC Class Codes: G01N 29/2412 : using the magnetostrictive properties of the material to be examined, e.g. electromagnetic acoustic transducers [EMAT]; investigating the presence of flaws using eddy currents G01N27/90, magnetostrictive transducers B06B1/08, measuring magnetostrictive properties G01R33/18
• CPC Class Codes: G01N 29/46 : by spectral analysis, e.g. Fourier analysis or wavelet analysis spectral signal processing per se G06F17/14

Abstract

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.

Claims

1. A thermoplastic rewelding method for forming a thermoplastic weld between at least two, fiber-reinforced composite laminates containing thermoplastic resin and repairing welded areas of inadequate strength, comprising the steps of:

(a) assembling at least two, fiber-reinforced, composite laminates containing thermoplastic resin to define a bond line along faying surfaces of the laminates;

(b) positioning a metal mesh susceptor along the bond line;

(c) heating the laminates along the bond line to form a thermoplastic weld between the laminates by inductively heating the metal mesh susceptor to melt, intermix, and fuse the resin around the metal mesh susceptor to weld the laminates together;

(d) nondestructively evaluating the thermoplastic weld quality by analyzing acoustic signals generated by electromagnetic pulses absorbed in the metal mesh susceptor; and

(e) rewelding in at least those regions of the thermoplastic weld found to have inadequate strength by reheating the metal mesh susceptor.