Cutting mechanism for carbon nanotube yarns, tapes, sheets and polymer composites thereof

Patent metadata

Field	Value
Publication number	US-11097440-B2
Application number	US-201615530055-A
Country	US
Kind code	B2
Filing date	Nov 7, 2016
Priority date	Nov 5, 2015
Publication date	Aug 24, 2021
Grant date	Aug 24, 2021

Abstract

A cutting mechanism includes electrodes that are utilized to cut or score a non-conductive outer material of a filament or sheet. The electrodes contact a conductive reinforcing material of the filament or sheet to complete an electric circuit. Electric current flows through and heats the conductive material to oxidize or otherwise separate/cut the conductive material and any remaining non-conductive material.

First claim

What is claimed is:

1. A method of cutting filaments comprising a conductive inner portion and outer portion disposed around the conductive inner portion, the method comprising:
providing first and second conductive electrodes, wherein both the first and second conductive electrodes comprise a blade having an edge configured to mechanically cut into the outer portion;
providing a voltage difference across the first and second conductive electrodes;
bringing the first and second conductive electrodes into contact with the outer portion;
applying force to the first and second conductive electrodes to thereby cause the first and second conductive electrodes to penetrate the outer portion and contact the conductive inner portion without mechanically cutting through the conductive inner portion, wherein the first and second conductive electrodes contact the conductive inner portion such that an electrical current flows through a local region of the conductive inner portion between the first and second conductive electrodes and degrades the conductive inner portion at the local region by oxidation to thereby cut the filament and stop the electrical current flow,
wherein the conductive inner portion comprises carbon.

2. The method of claim 1 , wherein:
the conductive inner portion has electrical resistance and the electrical current heats the local region of the conductive inner portion.

3. The method of claim 1 , wherein:
the filament comprises a carbon nanotube reinforced composite filament.

4. The method of claim 1 , including: utilizing a powered actuator to apply a force to move a support block to thereby move the filament toward the first and second conductive electrodes and apply the force to penetrate the outer portion and contact the conductive inner portion without mechanically cutting through the conductive inner portion.

5. The method of claim 1 , including:
manually applying a force to a support block to thereby move the filament toward the first and second conductive electrodes and apply the force to penetrate the outer portion and contact the conductive inner portion without mechanically cutting through the conductive inner portion.

6. The method of claim 1 , wherein:
the first and second conductive electrodes comprise spaced-apart blades that contact the filament at spaced-apart locations along the length of the filament.

7. The method of claim 1 , wherein:
the first and second conductive electrodes comprise blades having edges that are initially positioned on opposite sides of the filament and move toward each other during the cutting process.

8. The method of claim 1 , wherein:
the first electrode comprises an electrically conductive print nozzle of a 3D printing mechanism;
the second electrode comprises an electrically conductive member that is spaced-apart from the print nozzle; and
the method further comprises:
feeding the filament from the print nozzle and depositing a portion of the filament onto a substrate through the electrically conductive member; and
compacting the filament onto the substrate using the electrically conductive member, wherein applying force to the first and second conductive electrodes to thereby cause the first and second conductive electrodes to penetrate the outer portion and contact the conductive inner portion without mechanically cutting through the conductive inner portion comprises pulling the filament taut between the print nozzle and the electrically conductive member after compacting the filament such that the print nozzle and the electrically conductive member penetrate the outer portion and contact the conductive inner portion without mechanically cutting through the conductive inner portion; and
causing electrical current to flow through the print nozzle and the electrically conductive member to thereby cut the filament between the print nozzle and the electrically conductive member after pulling the filament taut.

9. The method of claim 1 , including:
monitoring the current flowing through the filament and/or the voltage across the filament to generate data; and
utilizing the data to provide control of the cutting process.

10. The method of claim 1 , wherein the electrical current is less than 3 amps and flows for less than 750 milliseconds.

11. A method of cutting composite material comprising at least one conductive carbon material in contact with a non-conductive material along a length of the composite material, the method comprising:
bringing first and second conductive electrodes into contact with the non-conductive material of the composite material wherein the first and second conductive electrodes include scoring blades;
applying a force to the first and second conductive electrodes to mechanically cut into the non-conductive material until the first and second electrodes contact the conductive carbon material without mechanically cutting through the conductive carbon material;
providing a voltage difference across the first and second electrodes to cause electrical current to flow through and oxidize the conductive carbon material to thereby degrade and cut the composite material and stop the flow of electrical current.

12. The method of claim 11 , wherein:
the composite material is formed as a sheet comprising at least one layer that is conductive and at least one layer of material that is non-conductive.

13. The method of claim 11 , wherein:
the composite material includes layers of non-conductive material on opposite sides of the conductive carbon material; and
wherein the first and second electrodes contacting the conductive carbon material includes the first and second electrodes contacting opposite sides of the conductive carbon material.

14. The method of claim 11 , including:
moving the first and second conductive electrodes relative to the composite material to thereby form an elongated kerf in the composite material.

15. The method of claim 11 , wherein:
the conductive carbon material comprises carbon nanotubes and/or carbon fibers; and
the composite material is formed as a sheet.

16. The method of claim 11 , wherein the electrical current is less than 3 amps and flows for less than 750 milliseconds.

17. The method of claim 11 , wherein the blades are rotatable and circular.

Assignees

• Nasa

Inventors

• Sauti Godfrey
• Kim Jae-Woo
• Siochi Emilie J
• Gardner John M

Classifications

• B29C64/209

  Heads; Nozzles · CPC title

• B29K2995/0005

  Conductive · CPC title

• B26F3/08 Primary

  with heated members · CPC title

• B29C64/118

  using filamentary material being melted, e.g. fused deposition modelling [FDM] · CPC title

• B29C64/30

  Auxiliary operations or equipment · CPC title