Apparatus and Method for Preform Relaxation and Flow Control in Liquid Composite Molding Processes

• US 20100072677A1
• Filed: 08/13/2009
• Published: 03/25/2010
• Est. Priority Date: 08/13/2008
• Status: Active Grant

• Current Assignee: University of Delaware
• Original Assignee: University of Delaware
• Inventors: Glancey, James L., Advani, Suresh G., Alms, Justin B.
• Granted Patent: US 8,210,841 B2
• Time in Patent Office: Days
• US Class Current: 264/511
• CPC Class Codes: B29C 70/443 and impregnating by vacuum or injection

Abstract

A vacuum-induced injection molding apparatus is disclosed. The apparatus includes a tool surface having an injection port extending therethrough. A flexible film extends over and is sealingly coupled to the tool surface. The flexible film comprises an outer surface and an inner surface such that the flexible film inner surface and the tool surface define a volume. A vacuum chamber is sealingly coupled to the outer surface of the flexible film. A vacuum port is in fluid communication with the volume. A method of injection molding a polymer matrix composite is also disclosed.

Claims

1. A vacuum-induced injection molding apparatus comprising:

a tool surface having an injection port extending therethrough;

a flexible film extending over a preform and sealingly coupled to the tool surface, wherein the flexible film comprises an outer surface and an inner surface such that the flexible film inner surface and the tool surface define a volume;

a vacuum chamber sealingly coupled to the outer surface of the flexible film; and

a vacuum port in fluid communication with the volume.

2. The vacuum-induced injection molding apparatus according to claim 1, wherein the vacuum chamber is releasably coupled to the outer surface of the flexible film.

3. The vacuum-induced injection molding apparatus according to claim 1, further comprising a resin supply coupled to the injection port.

4. The vacuum-induced injection molding apparatus according to claim 1, wherein the vacuum chamber comprises a rigid chamber.

5. The vacuum-induced injection molding apparatus according to claim 1, further comprising at least one stiffening bar extending between the flexible film and the vacuum chamber.

6. The vacuum-induced injection molding apparatus according to claim 1, wherein the vacuum chamber is sealing coupled to only a portion of the outer surface of the flexible film.

7. The vacuum-induced injection molding apparatus according to claim 1, further comprising an optional distribution media disposed between the flexible film and the tool surface.

8. A method of injection molding a polymer matrix composite comprising the steps of:

(a) providing a tool surface having an injection port extending therethrough;

(b) extending a flexible film over and sealingly coupling the flexible film to the tool surface, forming a volume;

(c) layering a plurality of fabric preforms within the volume;

(d) sealing an external vacuum chamber to the flexible film proximate to the injection port, wherein the external vacuum chamber includes a vacuum port;

(e) drawing a vacuum through the vacuum port, wherein the vacuum drawing draws the flexible film and the plurality of fabric preforms toward the vacuum port; and

(f) injecting a polymer resin through the injection port and between the plurality of fabric preforms.

9. The method according to claim 8, further comprising the steps of:

(g) removing the vacuum;

(h) unsealing the vacuum chamber from the flexible film;

(i) moving the vacuum chamber to a new location; and

(j) repeating steps (d)-(f).

10. The method according to claim 8, further comprising the step of applying a vacuum to the volume.

11. The method according to claim 10, wherein the step of applying a vacuum to the volume comprises drawing the polymer resin away from the injection port.

12. The method according to claim 8, further comprising disposing an optional distribution media between the flexible film and the fabric preforms.

13. The method according to claim 8, further comprising adding stiffening bars to the external vacuum chamber.