Extruded deposition of polymers having continuous carbon nanotube reinforcements

• US 10,118,375 B2
• Filed: 01/22/2015
• Issued: 11/06/2018
• Est. Priority Date: 09/18/2014
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Hickman, Gregory James Schoepen, Bogucki, Gregg Robert
• Primary Examiner(s): Leong, Nathan T
• Application Number:
  US14/602,964
• Publication Number:
  US 20160082659A1
• Time in Patent Office: 1,384 Days
• Field of Search: None
• CPC Class Codes: B05D 1/265 Extrusion coatings
• CPC Class Codes: B29B 15/122 with a matrix in liquid form, e.g. as melt, solution or latex
• CPC Class Codes: B29C 64/106 using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
• CPC Class Codes: B29C 70/24 oriented in at least three directions forming a three dimensional structure
• CPC Class Codes: B29K 2105/12 of short lengths, e.g. chopped filaments, staple fibres or bristles
• CPC Class Codes: B29K 2307/04 Carbon
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: C08J 2300/00 Characterised by the use of unspecified polymers
• CPC Class Codes: C08J 5/005 Reinforced macromolecular compounds with nanosized materials, e.g. nanoparticles, nanofibres, nanotubes, nanowires, nanorods or nanolayered materials

Abstract

A composite part is fabricated by rastering a deposition head over a substrate, and additively forming part features by extruding a polymer having an entrained continuous nanotube reinforcement from the deposition head onto a substrate.

Claims

1. A deposition fabrication method, comprising:

establishing a pressurized stream of a first polymer through a tube, wherein the first polymer has a first melt temperature;

entraining a carbon nanotube reinforcement within the pressurized stream, wherein the carbon nanotube reinforcement is pre-impregnated with a second polymer that has a second melt temperature, wherein the second melt temperature is higher than the first melt temperature, and wherein entraining is performed above the first melt temperature but below the second melt temperature, wherein as a result of entraining a combined polymer is formed;

maintaining a third temperature at a material supply end of an entrainment barrel that contains the tube at a higher temperature than a fourth temperature at a material deposition end of the entrainment barrel; and

depositing a bead of the combined polymer from the tube onto a substrate.

2. The deposition fabrication method of claim 1, wherein entraining the carbon nanotube reinforcement includes feeding a carbon nanotube yarn into the tube.

3. The deposition fabrication method of claim 1, wherein entraining the carbon nanotube reinforcement includes feeding aligned carbon nanotubes into the tube.

4. The deposition fabrication method of claim 1, wherein entraining the carbon nanotube reinforcement includes feeding a continuous length of mechanically interlocked carbon nanotubes into the pressurized stream.

5. The deposition fabrication method of claim 1, further comprising:

drawing the carbon nanotube reinforcement through the tube using the pressurized stream and capillary action.

6. The deposition fabrication method of claim 1, further comprising:

pre-impregnating the carbon nanotube reinforcement with a polymer, and

wherein entraining the carbon nanotube reinforcement includes continuously feeding the carbon nanotube reinforcement into the pressurized stream.

7. The deposition fabrication method of claim 1, further comprising:

heating the carbon nanotube reinforcement to a glass transition of the first polymer.

8. The method of claim 1, wherein the first polymer is different than the second polymer.

9. A method of fabricating a composite part, comprising:

providing a length of a carbon nanotube yarn;

providing a liquefied polymer;

feeding the carbon nanotube yarn and the liquefied polymer into a deposition head, including entraining, through an entrainment barrel, the carbon nanotube yarn within the liquified polymer, and wherein feeding and entraining further comprises;

feeding the carbon nanotube yarn into a guide tube disposed inside an annular inlet of the entrainment barrel, wherein the guide tube ends at an entrance to a capillary tube disposed inside the entrainment barrel;

flowing the liquified polymer into the annular inlet and around the guide tube, including flowing the liquified polymer past the guide tube and into the capillary tube via a convergence region in which the liquified polymer is allowed to flow onto the carbon nanotube yarn just as the carbon nanotube yarn enters the capillary tube;

rastering the deposition head over a substrate; and

additively forming features of the composite part by extruding the liquefied polymer having the carbon nanotube yarn entrained therein from the deposition head onto the substrate, wherein extruding includes extruding from the capillary tube that extends past an end of the entrainment barrel.

10. The method of claim 9, wherein the extruding includes forcing the liquefied polymer having the carbon nanotube yarn entrained therein through a tube and a die.

11. The method of claim 9, further comprising:

cutting the liquefied polymer having the carbon nanotube yarn entrained therein during rastering of the deposition head.

12. The method of claim 9, wherein extruding the liquefied polymer and the carbon nanotube yarn includes:

introducing the liquefied polymer and the carbon nanotube yarn into an upstream end of a tube,

forcing the liquefied polymer to flow through the tube to a downstream end of the tube, and

drawing the carbon nanotube yarn through the tube to the downstream end of the tube by using the flow through the tube to drag the carbon nanotube yarn along with the flow through the tube.

13. The method of claim 12, further comprising:

using capillary action to assist in drawing the carbon nanotube yarn through the tube.

14. The method of claim 12, wherein introducing the liquefied polymer and the carbon nanotube yarn includes injecting the liquefied polymer under pressure around the carbon nanotube yarn.

15. The method of claim 9, wherein providing a length of carbon nanotube yarn includes:

producing a plurality of carbon nanotube threads, and

mechanically interlocking the carbon nanotube threads.

16. The method of claim 15, wherein mechanically interlocking the carbon nanotube threads is performed by spinning the carbon nanotube threads together.

17. The method of claim 16, wherein producing the plurality of carbon nanotube threads includes aligning and coupling together a plurality of carbon nanotubes.

18. The method of claim 17, wherein producing the plurality of carbon nanotube threads includes impregnating the carbon nanotubes with a polymer.