Methods and apparatus associated with narrow tows fabricated from large-tow preforms

Patent metadata

Field	Value
Publication number	US-9707724-B2
Application number	US-16577508-A
Country	US
Kind code	B2
Filing date	Jul 1, 2008
Priority date	Jul 1, 2008
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

A method for using a tow incorporating a large number of fibers to form a composite part that has the quality of parts made with tows incorporating a small number of fibers is described. The method includes spreading the tows incorporating a large number of fibers to form a relatively wide, flat, and continuous, unidirectional fabric, holding the fabric under tension to maintain the orientation and flatness, subjecting the flattened fabric to melt-bonding while held under tension to maintain the flattened configuration, and slicing the melt-bonded, unidirectional fabric into a plurality of narrow fiber tows and subsequently using these to produce braided, woven, and other fabric forms.

First claim

What is claimed is:

1. A method for using tows incorporating a large number of fibers to form a composite part that has the quality of parts made with tows incorporating a small number of fibers, said method comprising:
spreading the tows incorporating a large number of fibers to form a relatively flat and continuous unidirectional fabric;
holding the continuous unidirectional fabric under tension to maintain the orientation and flatness;
applying a melt-bondable fabric to both a bottom and a top of the continuous unidirectional fabric;
passing the continuous unidirectional fabric including the melt-bondable fabric on the bottom and top of the continuous unidirectional fabric through an oven;
consolidating the melt-bondable fabric and the continuous unidirectional fabric in the oven while under tension;
slicing the melt-bonded, unidirectional fabric into a plurality of narrow fiber tows;
forming at least one of weaves and braids from at least some of the plurality of narrow fiber tows produced from slicing the melt-bonded, unidirectional fabric, thereby forming a woven or braided preform, wherein the woven or braided preform is dry and configured for subsequent infusion with a matrix resin.

2. A method according to claim 1 further comprising collecting melt-bonded fabric on a take-up roll in the form of a continuous, unidirectional fabric prior to slicing.

3. A method according to claim 1 further comprising collecting the narrow fiber tows on to individual spools suitable for subsequent processing.

4. A method according to claim 1 further comprising positioning multiple narrow fiber tows relative to one another to create a fabric.

5. A method according to claim 4 wherein positioning multiple narrow fiber tows relative to one another to create a fabric comprises arranging the narrow tows into at least one of a woven fabric and a braided fabric.

6. A method according to claim 1 wherein applying a melt-bondable fabric comprises applying a thermoplastic to the flattened fabric.

7. A method according to claim 6 wherein applying a thermoplastic to the flattened fabric comprises applying at least one of polyamide, polyimide, polyamide-imide, polyester, polybutadiene, polyurethane, polypropylene, polyetherimide, polysulfone, polyethersulfone, polyphenylsulfone, polyphenylene sulfide, polyetherketone, polyethertherketone, polyarylamide, polyketone, polyphthalamide, polyphenylenether, polybutylene terephthalate, and polyethylene terephthalate to the flattened fabric.

8. A method according to claim 1 wherein applying a melt-bondable fabric comprises applying a thermoplastic that is compatible with a matrix resin to the flattened fabric.

9. A method according to claim 6 wherein applying a thermoplastic to the flattened fabric comprises applying a thermoplastic material that has an area density of between about one and about 50 grams/square meter.

10. A method according to claim 1 wherein slicing the melt-bonded, unidirectional fabric into a plurality of narrow fiber tows comprises slicing the flattened sheet into tows that are substantially equivalent to a width associated with 1000 individual fibers.

11. A method according to claim 1 wherein slicing the melt-bonded, unidirectional fabric into a plurality of narrow fiber tows comprises slicing the flattened sheet into tows that have a width of approximately ⅛-inch in width.

12. A method according to claim 1 further comprising:
removing melt-bonded thermoplastic from the at least one of weaves and braids.

13. A method according to claim 12 further comprising applying fiber finishes to reconstitute a desired sizing for the narrow fiber tows.

14. A method for reducing an interstitial spacing between tows in a composite structure, said method comprising:
applying a melt-bondable fabric to both a bottom and a top of a continuous unidirectional fabric formed from a plurality of tows incorporating a large number of fibers;
passing the continuous unidirectional fabric including the melt-bondable fabric on the bottom and top of the continuous unidirectional fabric through an oven;
consolidating the melt-bondable fabric and the continuous unidirectional fabric in the oven;
fabricating a plurality of narrow fiber tows from the consolidated melt-bondable fabric and continuous unidirectional fabric by slicing the consolidated melt-bondable fabric and continuous unidirectional fabric; and
forming at least one of weaves and braids utilizing at least some of the narrow fiber tows produced from slicing the consolidated melt-bondable fabric and continuous unidirectional fabric, thereby forming a woven or braided preform, wherein the woven or braided preform is dry and configured for subsequent infusion with a matrix resin.

15. A method according to claim 14 further comprising spreading out the plurality of tows incorporating a large number of fibers to a substantially flat configuration to form the continuous unidirectional fabric.

Assignees

• Tsotsis Thomas K
• Boeing Co

Inventors

• Tsotsis Thomas K

Classifications

• Y10T442/60

  Nonwoven fabric [i.e., nonwoven strand or fiber material] · CPC title

• B29B15/12

  of reinforcements of indefinite length · CPC title

• D02J1/18

  Separating or spreading · CPC title

• B29C70/20 Primary

  oriented in a single direction, e.g. roofing or other parallel fibres {(B29C70/083, B29C70/226 take precedence)} · CPC title

• D04H1/54

  by welding together the fibres, e.g. by partially melting or dissolving (in combination with needling D04H1/485) · CPC title