METHOD OF CONSOLIDATING PRE-PREG MATERIAL PLY LAYERS
An induction heating compaction system is provided. The system includes an induction heating member and a compaction member. The induction heating member is configured to generate an electromagnetic field at a select frequency. The select frequency causes at least one of the fibers and matrix in pre-preg material to heat up. The compaction member has at least a portion that is made from a material that is transparent to the select frequency of the electromagnetic field generated by the induction heating member. The compaction member includes a cooling assembly that is configured and arranged to extract heat from the pre-preg material, while compacting the pre-preg material.
This application is a divisional of U.S. patent application Ser. No. 13/734,661, filed Jan. 4, 2013, pending, the disclosure of which is hereby incorporated herein in its entirety by this reference.
BACKGROUNDComposite products can be made from plies of pre-impregnated (pre-preg) material. Pre-preg material includes fibers surrounded by a matrix material, such as a thermosetting or thermoplastic resin or a ceramic matrix. Consolidation of individual ply layers together to form a composite laminate in a buildup is often critical to the quality of the finished composite product. Lack of compaction within the laminate during lamination, before it sees additional consolidation, such as a cure process, press, or other means, can result in wrinkling of the fibers in the laminate, reducing mechanical performance and affecting dimensional characteristics of the finished product. During consolidation it is common to apply heat to the plies of pre-preg material to heat up the matrix material to make the plies more compliant during consolidation. Typical methods of heating and consolidating composites including using hot gas to flood an area in front of a compaction member, using infrared heat to warm the material in front of a compaction member, and using a laser beam to heat material before it is rolled and compacted. Each of these methods requires space allocation for its heating source and space allocation for its compaction member. Many of these systems are energy and time intensive, or have inherent safety issues when an operator is in close proximity.
For the reasons stated above and for other reasons stated below that will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for a safe, effective and efficient system to consolidate plies of pre-preg material.
SUMMARYThe above-mentioned problems of current systems are addressed by embodiments of the present invention and will be understood by reading and studying the following specification. The following summary is made by way of example and not by way of limitation. It is merely provided to aid the reader in understanding some of the aspects of the invention.
In one embodiment, an induction heating compaction system is provided that includes an induction system or heating member and a compaction member. The induction heating member is configured to generate an electromagnetic field at a select frequency. The select frequency causes at least one of the fibers and matrix in pre-preg material to heat up. The compaction member is configured and arranged to extract heat from the pre-preg material, while compacting the pre-preg material.
In another embodiment, another induction heating compaction system is provided. The system includes a compaction member or device, an induction heating member, and a cooling assembly. The compaction member is configured and arranged to compact ply layers of pre-preg material. The induction heating member is received within the compaction member. The induction heating member is configured to generate an electromagnetic field at a select frequency. The select frequency causes at least one of the fibers and matrix in pre-preg material to heat up. The compaction member has at least a portion that is made from a material that is transparent to the select frequency of the electromagnetic field generated by the induction heating member, such that the induction field can be directed at a composite pre-preg material to be consolidated, while not heating up the compaction member. The cooling assembly is configured and arranged to extract heat from the pre-preg material to solidify the ply layers of pre-preg material in a compact configuration during an in-situ compaction buildup process.
In yet another embodiment, a method of consolidating pre-preg material ply layers is provided. The method includes: inductively heating an area of at least one of fibers and matrix in at least one first pre-preg material ply layer to soften the matrix in the heated area; and compacting the heated area of the at least one first pre-preg material ply layer during lay-up of the at least one first pre-preg material ply layer over a second pre-preg material ply layer.
The present invention can be more easily understood and further advantages and uses thereof will be more readily apparent, when considered in view of the detailed description and the following figures in which:
In accordance with common practice, the various described features are not drawn to scale but are drawn to emphasize specific features relevant to the present invention. Reference characters denote like elements throughout the figures and the specification.
DETAILED DESCRIPTIONIn the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the inventions may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the claims and equivalents thereof
One benefit of some embodiments of the present invention is that they provide an induction heating compaction system that is relatively compact to save space and make packaging easier. A tighter package allows more contour capability within automation systems. In an embodiment of the present invention, induction heating is used to heat conductive fibers in pre-preg material that, in turn, melts or softens the surrounding matrix to allow tight nesting or consolidation of one ply to a previous laid ply or plies, generally known as an “on-the-fly” or “in-situ” process. An example type of conductive fiber used in the pre-preg material is carbon fiber. Since carbon fiber is conductive, it will heat up when subjected to an alternating electromagnetic field of a given frequency, provided by an induction heater assembly. Besides conductive fibers, non-conductive fibers that are metallically coated could be used. In other embodiments, the matrix is formulated to react directly to the induction heating. In these embodiments, the matrix may be loaded with conductive particles. The conductive particles could be metallic, carbon nanofibers, nanofillers, etc. The conductivity components of the matrix would absorb the induction heating and soften the pre-preg. In yet another embodiment, both the fiber and matrix may react to the induction heating.
A compaction member is then used to compact the plies while still warm\hot as part of the in-situ compaction buildup process. The compaction member, of embodiments, extracts heat from the pre-preg material while compacting the lamina or laminate in a consolidated or cured state. In some embodiments, the compaction member is actively cooled for higher temperature materials or to allow faster process speeds. In embodiments, portions of a compaction member, particularly in the “field of view,” so to speak, of the induction field directed toward the composite material, are made from a material that is not affected by the select frequency of the electromagnetic field used to heat up the composite pre-preg material. Hence, in some embodiments, at least a portion of the compaction member is made from material that is transparent to the frequency of the electromagnetic field created by the induction heating member. Moreover, in some embodiments, at least some portions of the compaction member that are not transparent to the frequency of the electromagnetic field are shielded from the induction field.
Referring to
An example of an induction heating compaction system 400, of an embodiment, is illustrated in
Another example embodiment of an induction heater compaction system 500 is illustrated in
The compaction roller 450 is further illustrated in
An embodiment that uses a compaction foot (or shoe) 502 is illustrated in the assembled side perspective view of
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement, which is calculated to achieve the same purpose, may be substituted for the specific embodiments shown. This application is intended to cover any adaptations or variations of the present invention. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof.
Claims
1. A method of consolidating pre-preg material ply layers, the method comprising:
- laying-up at least one first pre-preg material ply layer over at least one second pre-preg material ply layer on a contoured surface of a forming tool;
- inductively heating an area of at least one of fibers or matrix in the at least one first pre-preg material ply layer to soften the matrix in the heated area with an induction heater of a compaction member;
- compacting the heated area of the at least one first pre-preg material ply layer during the lay-up of the at least one first pre-preg material ply layer over the at least one second pre-preg material ply layer;
- while compacting the heated area, extracting heat energy from the at least one first pre-preg material ply layer and the at least one second pre-preg material ply layer with a cooling member within the compaction member; and
- joining the at least one first pre-preg material ply layer and the at least one second pre-preg material ply layer in a compact state.
2. The method of claim 1, further comprising solidifying the at least one first pre-preg material layer and the at least one second pre-preg material ply layer in the compact state.
3. The method of claim 1, further comprising
- automatically laying up at least a portion of the at least one first pre-preg material ply layer over the at least one second pre-preg material ply layer.
4. The method of claim 1, further comprising generating induction heat of a given frequency to apply heat energy to the at least one of the fibers or matrix in the at least one first pre-preg material ply layer with the induction heater.
5. The method of claim 1, further comprising shielding at least some elements of the compaction member from heating effects of the induction heating.
6. The method of claim 1, further comprising actively cooling the compaction member that compacts the heated area to extract the heat energy from the at least one first pre-preg material ply layer and the at least one second pre-preg material ply layer.
7. The method of claim 1, wherein compacting the heated area of the at least one first pre-preg material ply layer comprises applying a force to the at least one first pre-preg material ply layer with a compaction roller of the compaction member.
8. The method of claim 1, wherein compacting the heated area of the at least one first pre-preg material ply layer comprises applying a force to the at least one first pre-preg material ply layer with a compaction foot of the compaction member.
9. The method of claim 1, wherein extracting heat from the at least one first pre-preg material ply layer and the at least one second pre-preg material ply layer comprises cooling the at least one first pre-preg material ply layer and the at least one second pre-preg material ply layer with at least one of cooling passages or heat sink material of the compaction member.
10. The method of claim 9, further comprising flowing at least one of a gas or a liquid through a flow path of the cooling passages.
11. A method of consolidating pre-preg material, the method comprising:
- laying-up at least one first pre-preg material over a surface of a forming tool;
- laying-up at least one second pre-preg material over the at least one first pre-preg material and the forming tool;
- inductively heating a portion of the at least one second pre-preg material with an induction heater of a compaction member;
- compacting the portion of the at least one second pre-preg material over the at least one first pre-preg material;
- while compacting the portion of the at least one second pre-preg material, extracting heat energy from the portion of the at least one second pre-preg material with a cooling member of the compaction member.
12. The method of claim 11, further comprising at least one of joining or solidifying the at least one first pre-preg material and the at least one second pre-preg material in a compact state.
13. The method of claim 11, wherein compacting the portion of the at least one second pre-preg material comprises applying a force to the at least one second pre-preg material with one of a compaction roller or a compaction foot of the compaction member.
14. The method of claim 11, wherein extracting heat from the at least one second pre-preg material comprises cooling the at least one second pre-preg material with cooling passages defined within the compaction member.
15. The method of claim 11, further comprising directing an electromagnetic field at a select frequency at the portion of the at least one second pre-preg material from the induction heater positioned within compaction member.
16. The method of claim 11, wherein extracting heat energy from the at least one second pre-preg material comprises transferring the heat energy from the at least one second pre-preg material to a portion of the cooling member within the compaction member.
17. The method of claim 11, further comprising inductive heating and extracting heat energy from the portion of the at least one second pre-preg material with the same component of the compaction member.
18. A method of consolidating material, the method comprising:
- laying-up a material over a surface of a forming tool;
- laying-up another material comprising fibers and matrix over the material and the forming tool;
- inductively heating a portion of the another material with an induction heater of a compaction member; and
- compacting the heated area of the another material solely with the compaction member while extracting heat from the another material with a cooling member within the compaction member.
19. The method of claim 18, further comprising directing an electromagnetic field at a select frequency at the portion of the another material from the induction heater positioned within compaction member.
20. The method of claim 18, further comprising actively cooling the another material with the cooling member.
Type: Application
Filed: Nov 3, 2016
Publication Date: Mar 23, 2017
Inventors: Vernon M. Benson (Morgan, UT), David R. Machac (Ogden, UT), Bryan J. Loveless (Perry, UT)
Application Number: 15/342,998