GB2268704A

GB2268704A - Layup preparation for fibre reinforced composites

Info

Publication number: GB2268704A
Application number: GB9215148A
Authority: GB
Inventors: Andrew Mills; Graham John Burley; Andrew Paul Godbehere
Original assignee: British Aerospace PLC
Current assignee: BAE Systems PLC
Priority date: 1992-07-16
Filing date: 1992-07-16
Publication date: 1994-01-19
Anticipated expiration: 2012-07-16
Also published as: GB2268705A; GB2268704B; GB2268705B; GB9314757D0; GB9215148D0

Abstract

In preparing a layup (21) of piles of fibrous material (16) for the manufacture of a fibre reinforced plastics composite a cutting table (1) is used, which has a frame (2) defining an open central cutting area (3), rollers (4, 5, 7, 8, 8, 10) to draw a length of the material (16, 17) thereacross and cutting means (15) to cut the piles (32) from the length of material (16), (17) to allow a cut ply (32) to fall through the open area (3) in the frame (2) onto a layup surface (12) whereby to avoid handling of the cut plies (32). <IMAGE>

Description

LAYUP PREPARATION FOR FIBRE REINFORCED COMPOSITES This invention relates to layup preparation for fibre reinforced composites.

It is known to prepare a fibre reinforced composite part by hand layup onto a curved mould tool. Hand layup may be assisted by automated ply profiling to profile individual plies at high speed. Layup of the plies still needs to be carried out by hand however, which is extremely time consuming and labour and skill intensive.

It is an object of the invention to provide apparatus and a method for laying up a fibre reinforced composites part which is faster and cheaper than at present possible.

According to one aspect of the invention there is provided a cutting table for preparing a layup of plies of fibrous material for the manufacture of a fibre reinforced plastics composite, the table having a frame defining an open central cutting area, means to draw a length of the material thereacross and cutting means to cut the plies from the length of material whereby to allow a cut ply to fall through the open area in the frame onto a layup surface.

The invention thus provides a means of laying up a composite part simply and without manual handling of the plies.

The cutting table may include at least one retractable support means extendable across the cutting area to support the fibrous material during cutting. The support means can then be drawn across the cutting area during cutting of the plies and subsequently withdrawn to allow the cut plies to fall onto the layup surface.

The at least one retractable support means may comprise a series of elongate members flexibly mounted adjacent one another and wound on a roller for drawing across the cutting area. A simple means of moving the support means across the cutting area which takes up minimal room when retracted is thus provided.

The at least one retractable support means may comprise a first fixed axis roller, a slatted portion wound thereon and a second travelling roller, the first roller and a free end of the slatted portion being located at one end of the open cutting area with the travelling roller engaging the slatted portion between the first roller and free end whereby to draw the slatted portion across the open cutting area when travelling in a first direction and to allow withdrawal of the slatted portion across the cutting area when travelling in a second direction.

This design of retractable support means avoids relative sliding motion between support means and cut plies during retraction.

The cutting table may include two retractable support means, one being positioned at either end of the cutting table.

The or each retractable support means may be adapted to apply a suction to the fibrous material supported thereby during cutting.

The retractable support means may also be adapted selectively to expel air under pressure to urge the fibrous material therefrom during retraction of the support means.

The cutting table may include clamping means to grip and support edges of the fibrous material adjacent the open cutting area to provide support during the cutting operation.

The cutting table may include means, eg a roller to draw the length of fibrous material and a length of resin film across the open cutting area together and may include means, eg opposed rollers to compress the fibrous material and resin film together to adhere one to the other. At least one of the rollers may be heated to assist mingling of the resin film and fibrous material together.

The cutting table may include means to consolidate the layup on the layup surface, for example one or more rollers or a vacuum bag.

The cutting table may include a layup table having a resiliently deformable sheet of material defining a said layup surface, the sheet of material preferably being supported by a series of spaced jacks adjustable for height in a programmed sequence. In this way cut plies, having fallen onto the flat layup surface may be formed to shape by deformation of the resiliently deformable sheet of material, thus automating the layup and forming sequence.

According to a second aspect of the invention there is provided a method of forming a layup of plies of fibrous material for the manufacture of a fibre reinforced plastics composite including the steps of drawing a length of the material across an open cutting area of a cutting table, cutting at least one piece of material from the length to form at least one ply and allowing same to fall through the open cutting area onto a layup surface beneath the table and repeating the above steps until a layup of the required thickness is formed.

The method may include the steps of extending support means beneath the length of material prior to cutting in order to support the material during cutting and subsequently progressively withdrawing the support means to allow the at least one cut ply progressively to drape onto the layup surface. Extending such support means beneath the material during cutting is carried out to react cutting forces if a cutting process such as laser cutting is not being used.

The method may include the step of combining the length of fibrous material with a length of resin film immediately prior to drawing the material across the open cutting area.

The invention will now be described by way of example with reference to the accompanying drawings of which: Figure 1 shows in perspective a cutting table according to one aspect of the invention, Figure 2 diagrammatically shows a layup sequence, Figure 3 shows in perspective a cutting table according to another aspect of the invention, Figure 4 is a side view showing a cutting table similar to figure 3 in operation, and Figure 5 shows in perspective a layup table comprised in the cutting table of figure 1.

Referring to figures 1 and 3, cutting tables 1 according to slightly different aspects of the invention are shown having a frame 2 defining an open central cutting area 3 and means to draw a length of material, eg multilayer non crimp carbon fibre fabric across the open cutting area in the form of rollers 4 and 5 at one end 6 of the table supplemented by rollers 7, 8, 9 and 10 at a second end 11 of the table (see figure 1). Rollers 4,7 and 8 are powered.

A layup surface 12 is provided which constitutes an upper surface of a deformable sheet of material 13 supported by a series of spaced jacks 14 (see figure 53 The cutting table includes cutting means in the form of an ultrasonic cutting knife 15 which is adapted to cut non crimp fabric fibrous material 16 combined with resin film 17 (see figure 1, figure 4) against retractable support means in the form of a retractable support table 18.

The cutting table further comprises a clamping means 19 on either side of the table to grip edges of the fibrous material 16 during cutting.

The cutting table includes a consolidation roller 20 (see figures 1 and 4) to roll across the layup surface 12 and consolidate a layup 21 (see figures 1 and 5).

Referring to figures 1 and 4, feed roller 7 carries a length of fibrous material 16 and feed roller 8 carries a length of resin film 17 mounted on a backing layer (not shown). The fibrous material 16 and resin film 17 are fed between two pressure rollers 9 and 10, both being heated, where the fibrous material 16 and resin film 17 are combined thence to proceed across the open cutting area 3 for cutting by the ultrasonic knife 15.

Referring to figure 1, the retractable support table 18 comprises a first roller 22 having a fixed axis, a second travelling roller 23 and a slatted portion 24 wound on the first roller 22. The slatted portion 24 has one end fixed at the first end of the table 6 at a level to support the fibrous material 16 as it passes over the open cutting area 3. The travelling roller 23 has its axis moveable in a horizontal plane along a slide 25 so as to pass across the open cutting ifeå 3. Bkd eenge ation roller 20 is also moveable along the slide 25 for rolling across the layup surface 12 during consolidation. Each slat of the slatted portion 24 is hollow and connectible to either a pressure source or a vacuum source.

The layup surface 12 forms the top surface of a layup table 26 which is adjustable in height (see figures 1, 3 and 5). The layup table 26 runs on rails 27 between work-stations of a flexible manufacturing centre (not shown).

Referring to figures 3 and 4, an alternative version of a retractable support table is shown having a first fixed storage roller 28 and an end roller 29 having a sacrificial layer thereon to form a support moveable underneath the ultrasonic cutting knife 15 during cutting. The retractable support table also includes a series of spaced intermediate rollers 30 joined by flexible connections 31 so as to be wound on the storage roller 28 when the table is retracted.

The version of figure 4 uses two cutting means moveable in unison to cut the fibrous material 16 against the end roller 29 simultaneously to form either side of a cut ply 32.

Figure 2 shows one method of laying up whole or part of a wing skin using an apparatus and method according to the invention. A first lay 33 extends between positions 34 and 35 and second to fifth lays, 36 to 39 extend for different distances between positions 34 and 35 to create a layup 21 of thickness tapering along its length. The layup as shown can be laid up in the flat on the deformable sheet of material 13 on the layup table 26 and thus can be fully automated using the cutting table of the invention. The layup table 26 is then lowered to clear the frame 2 of the cutting table and moved along the rails 27 to a workstation where the deformable sheet of material is slowly deformed by the jacks 14 into the desired shape, heat and pressure optionally being applied at this stage to ensure that the layup is consolidated and that no wrinkling of the material occurs.When formed in this way the part formed from the layup can be moved, either on the layup table or lifted from the layup table into an autoclave for final application of pressure and heat to cure if necessary.

In use, the cutting table 1 operates the roller system 4,5,7,8,9,10 to feed fibrous material 16 and resin film 17 through the pressure rollers 9,10 to combine them together and thence across the open cutting area 3. The rollers are then stopped. The layup table 26 is raised to its upper position so that the layup surface 12 sits just underneath the retractable support table 18. In figure 1 the retractable support table is extended across the open cutting area 3 by moving the travelling roller 23 underneath the open cutting area 3 to draw the slatted portion 24 thereacross thus unwinding the slatted portion 24 from the first roller 22. In figure 3 and figure 4 the rollers 29,30 are unwound from the storage roller 28 and moved across the open cutting area 3 to a position underneath the fibrous material 16 and resin film 17 where cutting is to begin.Cutting then takes place without movement of the retractable support table in the version shown in figure 1 and with corresponding movement along the cutting table 1 of the ultrasonic cutting knives 15 and end roller 29 in the version shown in figure 4.

In figure 4 as cutting takes place the cut ply 32 is allowed to drape down onto the layup surface 12 where it is immediately consolidated into the layup by the consolidation roller 20. In figure 1 it is optional whether the retractable support table 18 retracts during cutting or only after cutting has been completed. Indeed, if a small vertical gap is designed to be left between the retractable support table 18 and the path of the uncut fibrous material and resin film, then a complete layup can be formed on the retractable support table 18 before the same is retracted to allow the complete layup to drape onto the layup surface 12. It will be appreciated that movement of the rollers to feed further fibrous material and resin film across the open cutting area 3 between cutting operations is necessary. Unused material and resin is wound onto the roller 4 for subsequent use on smaller parts if necessary. After either each cut ply 32 or complete layup 21 has been draped onto the layup table 26, the consolidation roller 20 can be operated across the layup surface 12 to consolidate the layup.

The cutting table according to the invention can be as wide as is desired to allow extremely large components to be laid up in a single operation and in the flat. Great speed of layup may thus be achieved, also automation.

Claims

1. A cutting table for preparing a layup of plies of fibrous material for the manufacture of a fibre reinforced plastics composite, the table having a frame defining an open central cutting area, means to draw a length of the material thereacross and cutting means to cut the plies from the length of material whereby to allow a cut ply to fall through the open area in the frame onto a layup surface.

2. A cutting table as in claim 1 including at least one retractable support means extendable across the cutting area to support the fibrous material during cutting.

3. A cutting table as in claim 2 in which the at least one retractable support means comprises a series of elongate members flexibly mounted adjacent one another and wound on a roller for drawing across the cutting area.

4. A cutting table as in claim 3 in which the at least one retractable support means comprises a first fixed axis roller, a slatted portion wound thereon and a second travelling roller, the first roller and a free end of the slatted portion being located at one end of the open cutting area with the travelling roller engaging the slatted portion between the first roller and free end whereby to draw the slatted portion across the open cutting area when travelling in a first direction and to allow withdrawal of the slatted portion across the cutting area when travelling in a second direction.

5. A cutting table as in claim 3 or 4 including two retractable support means, one being positioned at either end of the cutting table.

6. A cutting table as in claim 2, 3, 4 or 5 in which the or each retractable support means is adapted to apply a suction to the fibrous material supported thereby during cutting.

7. A cutting table as in claim 6 in which the at least one retractable support means is adapted selectively to expel air under pressure to urge the fibrous material therefrom during retraction.

8. A cutting table as in any preceding claim including clamping means to grip and support edges of the fibrous material adjacent the open cutting area.

9. A cutting table as in any preceding claim including means to draw the length of fibrous material and a length of resin film across the open cutting area together and including means to compress the fibrous material and resin film together to adhere one to the other.

10. A cutting table as in claim 9 in which the means to compress the fibrous material and resin film together comprises opposed rollers at least one of which is heated.

11. A cutting table as in any preceding claim including means to consolidate the layup on the layup surface.

12. A cutting table as in claim 11 in which the means to consolidate the layup comprises a roller for rolling across the surface.

13. A cutting table as in any preceding claim including a layup table having a resiliently deformable sheet of material defining a said layup surface, the sheet of material being supported by a series of spaced jacks adjustable for height in a programmed sequence.

14. A method of forming a layup of plies of fibrous material for the manufacture of a fibre reinforced plastics composite including the steps of drawing a length of the material across an open cutting area of a cutting table, cutting at least one piece of material from the length to form at least one cut ply and allowing same to fall through the open cutting area onto a layup surface beneath the table and repeating the above steps as necessary until a layup of the required thickness is formed.

15. A method as in claim 14 including the steps of extending support means beneath the length of material prior to cutting in order to support the material during cutting and subsequently progressively withdrawing the support means to allow the at least one cut ply progressively to drape onto the layup surface.

16. A method as in claim 14 or 15 including the step of combining the length of fibrous material with a length of resin film immediately prior to drawing the material across the open cutting area.

17. A cutting table for preparing a layup of plies of fibrous material for the manufacture of a fibre reinforced composite substantially as described herein with reference to the accompanying drawings.

18. A method of forming a layup of plies of fibrous material for the manufacture of a fibre reinforced plastics composite substantially as herein described.