EP-4739487-A2 - NEEDLING AND WELDING SYSTEMS, METHODS, AND DEVICES

Abstract

A method for joining thermoplastic structures is disclosed. The method includes arranging a plurality of thermoplastic structures to form a joint, where the joint has a first side and a second side opposite the first side. The method also includes positioning a charge over a portion of the joint, where the charge comprises a plurality of needles. The method further includes welding the portion of the joint such that the thermoplastic structures are coupled. The welding includes applying a load to at least the first side of the joint or second side of the joint. The welding also includes heating the portion of the joint. The method additionally includes inserting the plurality of needles into the portion of the joint.

Inventors

• JACKSON, Robert, Lee
• SPAIN, David Simon, Wilhelm

Assignees

• Supernal, LLC

Dates

Publication Date

20260513

Application Date

20240705

Claims (20)

1. 1. A method for joining thermoplastic structures, the method comprising: arranging a plurality of thermoplastic structures to form a joint, wherein the joint has a first side and a second side opposite the first side; positioning a charge over a portion of the joint, wherein the charge comprises a plurality of needles; welding the portion of the joint such that the thermoplastic structures are coupled, wherein the welding comprises: applying a load to at least the first side of the joint or second side of the joint, and heating the portion of the joint; and inserting the plurality of needles into the portion of the joint.
2. 2. The method of claim 1, further comprising cooling the portion of the joint.
3. 3. The method of claim 1, further comprising determining a set process time, a set temperature, and a set impact frequency, wherein the portion of the joint is heated to the set temperature at a rate of heating defined by the set process time and set temperature, and wherein the plurality of needles are inserted at a rate of insertion defined by the set process time and set impact frequency.
4. 4. The method of claim 3, wherein the set process time, the set temperature, and the set impact frequency are based on a material property of at least one thermoplastic structure of the plurality of thermoplastic structures in the joint.
5. 5. The method of claim 4, wherein the material property is a glass transition temperature.
6. 6. The method of claim 3, wherein the set process time is based on a thickness of the joint and a material property of at least one of the plurality of thermoplastic structures.
7. 7. The method of claim 1, wherein heating the portion of the joint comprises heating the portion of the joint via inductive heating.
8. 8. The method of claim 1, wherein inserting the plurality of needles into the portion of the joint further comprises: determining an impact frequency, wherein an insertion rate for the plurality of needles is based on the impact frequency; and applying, at the determined impact frequency, an ultrasonic impact to the charge.
9. 9. The method of claim 1, wherein the charge further comprises a retaining piece for housing the plurality of needles.
10. 10. The method of claim 9, wherein inserting the plurality of needles into the portion of the joint comprises applying ultrasonic impact to the charge such that as the charge is compressed the plurality of needles transfer from the retaining piece into the portion of the joint, and wherein after the plurality of needles are inserted the retaining piece resides on the first surface.
11. 11. The method of claim 1, wherein a thermoplastic polymer used in each of the plurality of thermoplastic structures in the joint is the same.
12. 12. The method of claim 1, wherein a thermoplastic polymer of the plurality of needles is the same as a thermoplastic polymer of at least one of the plurality of thermoplastic structures in the joint.
13. 13. The method of claim 1, wherein subsequent to inserting the plurality of needles into the portion of the joint, the method further comprises welding, using inductive heating, the plurality of needles with the portion of the joint, wherein a thermoplastic polymer in the plurality of needles is melted to fuse with a thermoplastic polymer in the portion of the joint.
14. 14. The method of claim 1, wherein prior to inserting the plurality of needles into the portion of the joint, the method further comprises providing continuous cooling to the plurality of needles such that the plurality of needles is below a predetermined temperature, wherein the maximum temperature is based on a material property of the plurality of needles.
15. 15. The method of claim 1, wherein the plurality of needles are inserted into the portion of the joint at a substantially orthogonal angle to the first side.
16. 16. A device for joining a thermoplastic structure, the device comprising: a frame; an actuator coupled to the frame and configured to apply a load; a heating unit coupled to the frame; an impact driver coupled at a first end to the frame and at a second end to an impact plate, wherein the impact plate drivingly engages a charge, wherein the charge comprises a retaining piece and a plurality of needles disposed within the retaining piece; and a controller coupled to the frame and configured to: weld a portion of the thermoplastic structure, wherein the welding comprises: apply a load to a side of the portion of the thermoplastic structure, and heat the portion of the thermoplastic structure; and insert, using the impact driver, the charge into the portion of the thermoplastic structure.
17. 17. The device of claim 16, further comprising a cooling unit coupled to the frame and configured to provide below ambient temperature air to the charge, such that the plurality of needles are below a maximum temperature in the retaining piece.
18. 18. The device of claim 16, wherein the controller comprises a control panel configured to input: a set process time; a set temperature; and a set impact frequency.
19. 19. The device of claim 18, wherein at least one of the set process time, the set temperature, and the set impact frequency is based on a material property of the thermoplastic structure.
20. 20. The device of claim 16, wherein a material property of the plurality of needles is the same as a material property of the thermoplastic structure.

Description

Needling and Welding Systems, Methods, and Devices CROSS REFERENCE TO RELATED APPLICATION [0001] The present application claims priority to U.S. Provisional Application No. 63/525,651, filed on July 7, 2023, the entire contents of which are herein incorporated by reference as if fully set forth in this description. BACKGROUND [0002] Composite laminate structures, including parts and/or panels, may be used in a variety of industries, such as the aerospace industry, and may be favored for their high strength to weight ratio. It may be desirable to join together one or more composite laminate structures. Currently, adhesives may be used to bond the parts and/or structures together. In addition to adhesives, metal fasteners may be employed to better resist shear and/or peel loading on the joint and to help in transferring loading, and suppressing damage to and/or between the structures. To facilitate installation of the metal fasteners, holes may be drilled into the structures. This may break the fibers of the composite laminate and/or remove material, which may adversely affect the mechanical properties of the structure. Further, load transfer from the fasteners to the structure may create high localized stresses around the fastener holes which may result in various failure modes and/or damage to the composite laminate structure, such as delamination. [0003] Fastener holes may also allow moisture intrusion into a substructure posing corrosion concerns and/or affecting electronic components housed within the substructure. To mitigate such ingress sealants may be used, adding weight, cost and complexity. Additionally, metal fasteners and composite laminate structures may have differing coefficients of thermal expansion leading to large stresses that must be mitigated. When a vehicle structure, such as an aircraft structure, experiences large temperature ranges, differing coefficients of thermal expansion may result in conditions where the metal fastener does not properly fill the fastener hole (e.g., an over-expanded condition or an under-expanded condition). This may ultimately affect how load transfers throughout the structure and may require added structural weight to account for these conditions. [0004] Accordingly, the present invention seeks to improve structures in a way that effectively transfers loading through the structure. SUMMARY [0005] Embodiments described herein relate to welding and needling of parts and/or structures, such as fiber reinforced needling with both conductive and non-conductive fibers, as well as unreinforced needles and welding, and, more particularly, to systems, methods, and devices for needling and welding of thermoplastic structures. [0006] In a first example embodiment, a method for joining thermoplastic structures is provided. The method includes arranging a plurality of thermoplastic structures to form a joint, where the joint has a first side and a second side opposite the first side. The method also includes positioning a charge over a portion of the joint, where the charge includes a plurality of needles. The method further includes welding the portion of the joint such that the thermoplastic structures are coupled. The welding includes applying a load to at least the first side of the joint or second side of the joint. The welding also includes heating the portion of the joint. The method additionally includes inserting the plurality of needles into the portion of the joint. [0007] In an embodiment, the method further includes cooling the portion of the joint. [0008] In an embodiment, the method further includes determining a set process time, a set temperature, and a set impact frequency, where the portion of the joint is heated to the set temperature at a rate of heating defined by the set process time and set temperature, and where the plurality of needles are inserted at a rate of insertion defined by the set process time and set impact frequency. [0009] In such an embodiment, the set process time, the set temperature, and the set impact frequency are based on a material property of at least one thermoplastic structure of the plurality of thermoplastic structures in the joint. [0010] In such an embodiment, the material property is a glass transition temperature. [0011] In such an embodiment, the set process time is based on a thickness of the joint and a material property of at least one of the plurality of thermoplastic structures. [0012] In an embodiment, heating the portion of the joint includes heating the portion of the joint via inductive heating. [0013] In an embodiment, inserting the plurality of needles into the portion of the joint further includes determining an impact frequency, where an insertion rate for the plurality of needles is based on the impact frequency, and inserting the plurality of needles into the portion of the joint also includes applying, at the determined impact frequency, an ultrasonic impact to the charge. [0014] In an embodiment,