This disclosure generally relates to methods and equipment for curing up composite parts, and deals more particularly with a cure tool having an integrated edge breather and a method of making the tool.
Composite parts may be manufactured by laying up fiber reinforced composite plies on a tool either by hand or using automated fiber placement equipment. A vacuum bag may be placed over the layup and sealed to the tool. The part may then be cured, often by placing the layup in an autoclave where it is subjected to heat and pressure. During curing, a vacuum in the bag may help remove entrapped air and volatiles from the layup.
During the vacuum bagging process, edge breather materials may be placed adjacent or over the edges of the layup which allow the edges to “breathe” before and during curing. The breather materials maintain a volume of space around the edges of the layup so that the entrapped air and volatiles may escape the layup and be drawn away from the bag by the applied vacuum.
The breather materials may comprise, without limitation, non-woven nylon and polyester mats, woven fiberglass, as well as metal chains, braids and meshes. These types of breather materials may not be suited for re-use, and therefore may require replacement each time a layup is cured. The consumable nature of such breathers may render them costly to use in terms of both materials and the labor required to replace them after each cure cycle. Also, consumable types of breather materials may sometimes partially compress or collapse under the force applied by the bag, thereby reducing the volume of space around the edges of the layup which may in turn reduce the ability of the edges to breathe.
Accordingly, there is a need for an edge breather that eliminates the need for consumable breather materials while providing a relatively large and consistent volume of space around the edges of the layup that may aid in evacuating air and volatiles from the layup during curing.
The disclosed embodiments provide an edge breather for use in curing composite layups that is integrated into a cure tool used in curing the layup, such as that used during autoclave curing. The breather is produced by forming permanent breathing features directly into the surface of the tool, thus eliminating the need for the repeated installation of consumable breather materials. Because the breather is integrated into the tool, the volume over which the edges of the layup are allowed to breathe may be controlled and remains constant to provide a substantially continuous breathing volume during the cure cycle. The disclosed edge breather may be particularly effective at higher curing pressures where prior consumable edge breathing materials may tend to “pinch-off” and thereby restrict air flow around the edges of the layup.
According to one disclosed embodiment, a tool is provided for curing a composite layup. The tool includes a tool body having a surface adapted to support a composite part layup thereon. The tool body includes a breather for allowing removal of the air from the layup during curling. The breather is formed in the tool body surface as a network of recessed channels that extend substantially around a layup, placed on the tool body surface. The network of channels includes a first set of channels extending generally parallel to each other, and a second set of channels extending transverse to the channels in the first set. The breather may further include at least one passageway in the tool body that is coupled with the network of channels and is adapted to be connected with a vacuum source for drawing air away from the edges of the layup through the channels.
According to another disclosed embodiment, a tool is provided for curing a composite layup that includes a tool body having an upper surface adapted to support a composite layup thereon. The tool body includes a plurality of channels in the upper surface that generally surround the layup. The channels are adapted to be coupled with a vacuum source for allowing the edges of the layup to breathe during curing of the layup. The channels may include first and second sets of channels that extend transverse to each other. At least one internal passageway in the tool body couples the channels with the vacuum source. The passageway may be coupled with the channels at the intersection of the two sets of channels, or within one of the channels. The channels may be laterally spaced apart from each other and may each have a cross section that is either generally U-shaped or V-shaped.
According to another embodiment a method is provided of making a tool for curing a composite layup. The method includes fabricating a tool body having a surface for supporting a layup thereon. The method further includes forming a breather in the tool body for allowing air to be drawn from the layup during curing. Forming the breather may include forming a breather area in the supporting surface of the tool body by forming channels in the supporting surface. Forming the breather may further include forming an air passageway in the tool body connected with the channels and adapted to be coupled with a vacuum source. The channels may be formed by machining or molding.
According to still another embodiment, a method is provided for removing air and volatiles from a composite layup during curing. The method includes placing the layup on a cure tool and vacuum bagging the layup. Channels in the cure tool are used to draw air and volatiles from edges of the layup by applying a vacuum to the channels.
The disclosed embodiments satisfy the need for an edge breather that may reduce or eliminate the need for consumable breather materials and which provides a relatively large, consistent volume around the edges of a layup to facilitate edge breathing.
Referring first to
The part layup 22 is supported on the upper surface 20a of the cure tool body 25, within a central region 20c. A vacuum bag 32 covers the part layup 22 and is sealed to the upper surface 20a of the body 25 by means of sealer tape 34 which extends around the entire perimeter of the part layup 22 to form a vacuum tight seal between the bag 32 and the tool 20. The vacuum bag 32 may comprise any of a variety of materials, including but not limited to a flexible polymer film, such as Nylon®, Kapton® or PVA (polyvinyl alcohol). The part layup 22 may be optionally covered by a caul plate 26 used to control the distribution of pressure applied to the part layup 22 during the cure cycle. A parting film 28 covers the caul plate 26 and aids in removing the bag 32 following the cure cycle. A surface breather 30 is sandwiched between the parting film 28 and the vacuum bag 32. A mold release film 24 may be applied to the upper surface 20a of the cure tool 20 in order to facilitate release of the part layup 22, as well as the parting film 28 and surface breather 30, following completion of a cure cycle. It should be noted here that
An edge breather 35 is formed in the cure tool 20 along its periphery 36, between the outer edges 22a of the part layup 22 and the sealer tape 34. The edge breather 35 comprises a network 37 of channels that includes channels 38 formed in the upper surface 20a of the tool body 25. As used herein, the term “channel” or “channels” is used in its broadest sense, and is intended to include, without limitation, openings, recesses, grooves, slots, crevices and depressions formed in the surface 20a of the tool body 25 which have a size and/or a configuration sufficient to receive and collect air and volatiles drawn from the part layup 22 through the edges 22a the during the cure process. The channels 38 may have cross sections that are constant or which vary over their lengths. As best illustrated in
The body 25 of the cure tool 20 may be fabricated from various types of materials, depending upon the application, such as, for example and without limitation, metal, rubber and composites such as carbon fiber. The channels 38 may be formed in the cure tool 20 using any of various techniques, depending upon the application and the type of material from which the cure tool 20 is made. For example and without limitation, the channels 38 may be formed by machining or molding.
Attention is now directed to
Referring now to
Attention is now directed to
Next at 54, a breather 35 is formed in the body 25 of the tool 20 manufactured in step 52. Forming the breather 54 includes forming a first set of channels 38 in the tool surface 20a, as shown at step 56. At step 58, a second set of channels 48 is formed in the tool surface 20a which extend transverse to and intersect the first set of channels 38, 48 formed in steps 56 and 58 may be produced by machining molding or other known forms of material removal and/or production processes. At step 60, one or more passageways 40 are formed in the body 25 of the tool 20, also by machining, drilling, molding or similar types of production processes.
Referring now to
Embodiments of the disclosure may find use in a variety of potential applications, particularly in the transportation industry, including for example, aerospace, marine and automotive applications. Thus, referring now to
Each of the processes of method 72 may be performed or carried out by a system integrator, a third party, and/or an operator (e.g., a customer). For the purposes of this description, a system integrator may include without limitation any number of aircraft manufacturers and major-system subcontractors; a third party may include without limitation any number of vendors, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, and so on.
As shown in
The cure tool and method of making the same may be employed to cure composite parts during any one or more of the stages of the production and service method 72. For example, components or subassemblies corresponding to production process 80 may incorporate composite parts that are cured using the disclosed cure tool. Also, one or more method embodiments, or a combination thereof may be utilized during the production stages 80 and 82, for example, by substantially expediting assembly of or reducing the cost of an aircraft 74. Similarly, the disclosed cure tool may be used to cure composite parts that are utilized while the aircraft 74 is in service.
Although the embodiments of this disclosure have been described with respect to certain exemplary embodiments, it is to be understood that the specific embodiments are for purposes of illustration and not limitation, as other variations will occur to those of skill in the art.
Number | Name | Date | Kind |
---|---|---|---|
3146148 | Mitchella et al. | Aug 1964 | A |
4216047 | Hilliard et al. | Aug 1980 | A |
4548859 | Kline et al. | Oct 1985 | A |
4622091 | Letterman | Nov 1986 | A |
4869770 | Christensen et al. | Sep 1989 | A |
4902215 | Seemann, III | Feb 1990 | A |
4942013 | Palmer et al. | Jul 1990 | A |
5052906 | Seemann | Oct 1991 | A |
5242651 | Brayden et al. | Sep 1993 | A |
5316462 | Seemann | May 1994 | A |
5403537 | Seal et al. | Apr 1995 | A |
5439631 | Schneider et al. | Aug 1995 | A |
5439635 | Seemann | Aug 1995 | A |
5443778 | Schlingman | Aug 1995 | A |
5464337 | Bernardon et al. | Nov 1995 | A |
5589016 | Hoopingarner et al. | Dec 1996 | A |
5601852 | Seemann | Feb 1997 | A |
5665301 | Alanko | Sep 1997 | A |
5686039 | Merry | Nov 1997 | A |
5702663 | Seemann | Dec 1997 | A |
5709893 | McCarville et al. | Jan 1998 | A |
5714179 | Goodridge et al. | Feb 1998 | A |
5939013 | Han et al. | Aug 1999 | A |
6024555 | Goodridge et al. | Feb 2000 | A |
6555045 | McClure et al. | Apr 2003 | B2 |
6656411 | McClure et al. | Dec 2003 | B1 |
6861017 | McCarville et al. | Mar 2005 | B1 |
6964561 | Louderback et al. | Nov 2005 | B2 |
7029267 | Caron | Apr 2006 | B2 |
7681835 | Simpson et al. | Mar 2010 | B2 |
7931852 | Kieffer | Apr 2011 | B2 |
20070182071 | Sekido et al. | Aug 2007 | A1 |
Number | Date | Country | |
---|---|---|---|
20100291258 A1 | Nov 2010 | US |