GB2492221A

GB2492221A - Preformer apparatus

Info

Publication number: GB2492221A
Application number: GB1210874.2A
Authority: GB
Inventors: Elwyn Agnew
Original assignee: WILLIAMS IND SERVICES Ltd
Current assignee: WILLIAMS IND SERVICES Ltd
Priority date: 2011-06-20
Filing date: 2012-06-20
Publication date: 2012-12-26
Anticipated expiration: 2032-06-20
Also published as: GB201210874D0; GB201110400D0; GB2492221B

Abstract

A first inter-related product is provided in the form of a preformer apparatus 2 comprising one or more ground engaging supports 4, a hood 6, and a diaphragm frame 8 that is adapted to receive and hold a diaphragm, wherein the hood is movably mounted to the ground engaging supports between which it extends, and wherein the diaphragm frame is mounted to the hood from which it is independently movable. A second inter-related product is provided in the form of table which is adapted to support a forming tool and which is adapted for location in use generally below the hood. Preferably, the diaphragm frame is mounted to the hood via a plurality of shafts; downward motion of the hood lowers the diaphragm frame into place on the table, the weight of the diaphragm frame providing a seal around the table. The preformer apparatus is suitable for use with dry carbon fibre fabric, pre-preg and other woven materials and particularly, but not exclusively, for use in the manufacture of large scale composite items, for example, aircraft wing and fuselage components.

Description

Preformer Apparatus The present invention relates to an improved preformer apparatus suitable for use with dry carbon fibre fabric, pre-preg and other woven materials and particularly, but not exclusively, for use in the manufacture of large scale composite items, for example, aircraft wing and fuselage components.

As manufacturers strive to reduce weight and to improve strength and fatigue properties, the use of composite materials in aerospace and other industries is becoming increasingly commonplace with many components previously manufactured from metals now being produced or formed from composites. Various composite production techniques are employed including compression moulding and vacuum moulding, the preformer apparatuses used typically comprising a movable hood which is lowered over a table which is positioned below said hood, the table being adapted to support a forming tool over which a composite layup or pre-preg (often referred to as a preform') is placed for forming. ln use, a flexible covering or sheet, commonly known as a diaphragm or a membrane, is draped over the composite layup or pre-preg with vacuum being applied between the diaphragm and the table to cause the composite material to conform to or take up the shape of the tool below. When the hood is lowered into position over the table to generally encase or surround the tool, heat is applied by heating elements located within the hood and the composite layup or pre-preg is cured over the tool. Once cured, vacuum is pressure is reduced, the hood is raised, the diaphragm lifted off and the formed composite part is removed from the tool.

Generally, such apparatuses are based around equipment which is primarily designed for small-scale production in research and development environments where control, output quality, cycle times, robustness, ease of use, repeatability even safety is not given adequate consideration. Nevertheless, whilst not entirely suited to large scale manufacturing, such preformers have found use in production environments where their limitations and drawbacks are readily apparent.

According to a first aspect of the invention a first inter-related product is provided in the form of a preformer apparatus comprising one or more ground engaging supports, a hood, and a diaphragm frame that is adapted to receive and hold a diaphragm, wherein the hood is movably mounted to the ground engaging supports between which it extends, and wherein the diaphragm frame is mounted to the hood from which it is independently movable, and according to a second aspect of the invention a second inter-related product is provided in the form of table which is adapted to support a forming tool and which is adapted for location in use generally below the hood.

Advantageously, the diaphragm frame is mounted to the hood via a plurality of shafts.

In one embodiment of the invention, the diaphragm frame is suspended from the hood by the shafts which are mounted to the hood via bushings.

When the hood is fully raised, the diaphragm frame is suspended below the hood with the shafts extended from the hood. In this way, the diaphragm frame is extensible from and to the hood.

Conveniently, downward motion of the hood lowers the diaphragm frame into place onto a table which is adapted to support a forming tool and which is situated in use in the space between the ground engaging supports and generally below the hood. In this way, the weight of the diaphragm frame provides a seal around the table which it contacts in use.

This sealing contact may be augmented by the force of the hood when it is further lowered onto a diaphragm frame seated on the table, whereby the shafts will have generally retracted upwardly into the hood. In this way, the hood is pressed downwardly onto the diaphragm frame while said frame is seated on the table in use. Subsequent raising of the hood causes the shafts to extend from the hood thus allowing the diaphragm frame to remain on the table. The diaphragm frame will remain on the table until the shafts are extended once again from the hood i.e. reach their full downward stroke, after which further raising of the hood causes the shafts to lift the diaphragm frame from the table surface. In this way, the hood and diaphragm frame can be raised and lowered with respect to the table.

In an alternative embodiment of the invention, at least one shaft is motor driven so that the diaphragm frame is independently movable relative to the hood.

Conveniently, the diaphragm frame can therefore be driven into place onto a table which is adapted to support a forming tool and which is situated in use in the space between the ground engaging supports and generally below the hood. In this way, the downwards forces exerted by the at least one motor driven shaft upon the diaphragm frame enable the frame to provide a seal around the table which it contacts in use. in this way, the hood and diaphragm frame can be raised and lowered with respect to the table.

Conveniently, the ability of the hood to be raised from, or lowered proximate to, the diaphragm frame and the diaphragm when said diaphragm frame and diaphragm are in sealing engagement with the table and/or a tool or tools located thereon, enables a vacuum seal to be established and maintained between the diaphragm and the tool or tools while allowing the hood the hood to be raised to facilitate visual inspection of the tool(s), table and the composite part(s) being formed throughout the forming process. This obviates the need to provide windows in the hood for visibility into the apparatus and provides an operator with both visual and physical access to inspect parts being formed.

Advantageously, the ability of the hood to be raised from, or lowered proximate to, the diaphragm frame and the diaphragm when said diaphragm frame and diaphragm are in sealing engagement with the table and/or a tool or tools located thereon allows variable table heights to be used with the preformer apparatus.

Whilst it is envisaged that the apparatus of the present invention can readily accommodate tables in the height range of 300 mm to 1400 mm, the apparatus is not limited in size for it can readily be scaled up or down. The capability of the preformer apparatus to accommodate a range of table heights in turn allows tools of significant height profile to be used and large parts [e.g. aircraft fuselage sections, wing spars, nacelles, cowlings) or curved or stepped parts to be formed.

Advantageously, the ground engaging supports are counterbalanced. This allows the preformer apparatus to be free-standing without any requirement to be affixed to a floor.

Conveniently, the hood is mounted to the ground engaging supports by guide means comprising a plurality of shafts along which the hood is vertically movable.

In a preferred embodiment, the hood is vertically translated along the shafts by means of one or more ballscrews. Ideally, the or each baliscrew is servo motor controlled. Where more than one ballscrew is provided, ballscrew servo motors are synchronised by a controller. In this way, the hood can be quickly and accurately positioned and can be maintained in correct horizontal alignment throughout its vertical upward and downward travel.

Ideally, the or each ballscrew comprises a dual row ballscrew. Preferably, the or each dual row ballscrew comprises a 20 to 1 gearing ratio which advantageously prevents the hood from downwards creep'.

In a preferred embodiment, the or each ballscrew servo motor is provided with motion control means which prevents hood travel overshoot and applies braking if overrun is detected.

In a preferred embodiment, the hood is provided with a mechanical brake which is operable to stop and maintain the hood in position when power to the prefromer apparatus is interrupted.

In a preferred embodiment the hood and/or guide means is further provided with a part detection system which is operable to detect the presence of an obstacle as the hood is being lowered, the detection system preferably comprising a limit switch which operates on a floating plate which carries the weight of the hood. In this way, if the hood is lowered onto a part or object, the floating plate will detect the contact with the obstruction and further lowering of the hood will be stopped. This protects tools on the table and the hood from being damaged.

Advantageously, the hood comprises a latticed superstructure adapted to support the weight of the hood, to provide rigidity and to mitigate bending or twisting moments. Conveniently, the superstructure further provides means to house and support heating means and air extraction means as well as the diaphragm frame.

In one embodiment, the diaphragm frame comprises an integrated seal on its underside (i.e. table engaging surface) which is adapted to make sealing contact with the table which it abuts in use.

Ideally, the integrated seal is a high profile seal.

Ideally, the integrated seal is an elongate seal comprising at least a first and second limb, the first limb being affixable to the underside of the diaphragm frame, the second limb being a free limb extending from the first limb such that the seal is compressible. In this way, when vacuum is applied, the diaphragm frame may be drawn more tightly against the table.

In a preferred embodiment, the angle defined between the first and second limbs of the integrated seal is less than 900. In this way, the integrated seal substantially resembles a 7' shape in section.

The provision of the integrated seal ensures vacuum integrity of the diaphragm frame and diaphragm with the table top thereby obviating the need to provide specially adapted machined surfaces and/or the use of seal compounds on the table and/or diaphragm frame to achieve an effective seal therebetween. In use, the seal strength increases in proportion with vacuum strength.

Advantageously, the provision of the integrated seal on the diaphragm frame obviates the need for further clamping means to hold the diaphragm frame to the table to create a vacuum seal as would otherwise be the case with prior art preformers.

In one embodiment, the diaphragm frame comprises upper and lower in use sections, the lower section being separably demountable from the upper section so that the frame may clamp a diaphragm which it receives and holds.

Ideally, the respective upper and lower in use sections are each provided with complementary formations which engage with the margins of a diaphragm to be clamped when said respective sections of the frame are fastened together by suitable releasable fastening means. Conveniently, a deformable bead may be inserted in a space defined between the upper and lower in use sections of the diaphragm frame to augment the clamping of the diaphragm to the diaphragm frame.

Advantageously, the provision of such a clamping system enables up to 20m of diaphragm material to be replaced by two operators within 30 minutes.

Advantageously, the diaphragm clamping system enables diaphragm tension to be readily adjusted.

In one embodiment of the invention, at least one of the ground engaging supports is provided with means to receive and store a supply of diaphragm material which can be dispensed to the diaphragm frame, the diaphragm material generally being delivered to the apparatus in the form of a roll.

In a further aspect of the invention, the preformer apparatus further comprises trolley guide means to ensure that tables in the form of movable trolleys are accurately locatable within the space between the ground engaging supports and generally below the hood.

In a preferred arrangement, the trolley guide means, comprises a pair of spaced apart rollers which are mounted to at least one ground engaging support It is envisaged that rollers may be mounted directly to the supports or via a suitable intermediate structure which provides additional clearance between the trolley and the support In use, the rollers act as a receiving means which guide a trolley, by means of a complementary member provided on said trolley, into a correctly aligned position within the apparatus.

Ideally, the complementary member comprises a generally triangular shape having convergent sides which enable the member to generally move towards, and subsequently into, the gap between the spaced apart rollers during initial positioning. In this way, when correctly and fully seated, the respective convergent sides of the complementary member will each be in contact with a roller.

Advantageously, when correct seating is attained, the trolley, and thus table, will be in accurate longitudinal and transverse alignment with the preformer apparatus.

According to one embodiment of the invention, the hood further comprises heat sources in the form of a plurality of fast response medium wave infrared emitters.

Conveniently, the fast response medium wave infrared emitters are tuneable to their frequency of the carbon fibre of the layup or pre-preg being formed.

Advantageously, this ensures that maximum energy is absorbed by the layup or pre-preg to be formed. Such infrared emitters enable the carbon surface temperature of the part to be formed to 115°C within 15 minutes of operation. In addition, the infrared emitters have capability to penetrate through a 10mm depth of carbon fibre within 10 minutes of operation, thereby improving heating rates and reducing energy consumption costs.

Advantageously, the infrared emitters are mounted on electrically actuated adjustable mountings to provide optimum angle and position relative to specific parts being formed.

In a further aspect of the invention, the preformer apparatus is provided with a multizone control system for control over the infrared emitters such that complex tool shapes can be maintained within the apparatus at uniform temperature.

Advantageously, the provision of a multi zone control system for control over the infrared emitters also enables the apparatus to be operated at full capacity whereby a plurality of tools can occupy the table so that all available space is used, the multizone control system enabling specifically tailored heat profiles or energy emission to be applied simultaneously to specific parts being formed on the separate tools, Le. each part on the table occupying a defined zone that is separately heated according to its own specific requirements.

Ideally, the infrared emitters are arranged in banks, each bank being adjustable about two planes to enable heat to be directed evenly across multiple zones and which ensures minimal cross-over of heat between said zones as well as uniform heating across complex shaped parts being formed.

According to one embodiment of the present invention, the hood further comprises a plurality of high temperature pyrometers which enable non-contact temperature control. In conjunction with the multizone control system, the provision of high temperature pyrometers ensures that the infrared heating elements in each zone are accurately controlled so as to apply correct heat profiles to any one of the variety of shapes and sizes of component which may be formed on the table simultaneously, with each zone being separately temperature controlled.

Advantageously, the provision of high temperature pyrometers provides precision non-contact temperature control means which obviates the need for control thermocouples to be positioned by an operator.

Conveniently, the pyrometers are provided on adjustable mountings to enable them to be operative at a multitude of angles thereby ensuring their placement is generally central relative to the parts being monitored. In this way, optimum temperature control is possible. Ideally, the adjustable mountings comprise an adjustable ring provided under the pyrometers which enables an operator to direct the pyrometer without moving any covers on the part being formed or without the breaking the vacuum seal.

In a further embodiment of the invention, a laser provided on each pyrometer enables positioning of each pyrometer to be more readily achieved. In this way, a blue print' of the machine configuration can be recorded for a specific tool or part to be formed.

In a further aspect of the invention, the preformer is provided with embedded tool thermocouples which can be monitored to ensure that the carbon materials being formed are maintained within correct temperature specifications. This prevents carbon scorching or drying out of binder or matrix materials.

In a further aspect of the invention, the preformer is provided with means to dispense an insulation material adapted to augment the heating of composite layups or pre-pregs during forming while preventing overheating of the base of the forming tools. Conveniently, the means dispense the insulation material comprises a motorized winch assembly provided at one end of the hood, the winch assembly further comprising a cable adapted to draw the insulation material from a suitable dispenser arranged at the opposing end of the hood, so that the insulation material is drawn at least partially across the width of the hood in use. In a preferred embodiment, the insulation material dispenser is adapted to retract the insulation material away from the winch assembly and return it to said dispenser.

The invention will now be described in relation to the accompanying drawings, which show, by way of example only, embodiments of a p reformer apparatus: Figure 1 is a schematic perspective view of a preformer apparatus in accordance with the present invention; Figure 2 is a schematic illustration of the preformer apparatus shown with a hood outer covering removed; Figure 3 is a schematic illustration of a hood guide means; Figure 4 is a detailed schematic illustration showing an obstacle detection means in accordance with the invention; Figure 5 is a detailed schematic illustration showing sealing means provided on a diaphragm frame in accordance with the invention; Figures 6 and 7 are schematic illustrations showing a diaphragm material storage and dispensing system in accordance with the invention; Figures 8 and 9 are schematic illustrations showing a trolley guide means in accordance with the invention; and Figures lOa -lOc are schematic cut-away illustrations showing an exemplary insulation material dispensing means in accordance with the invention.

Referring to the drawings, Figure 1 shows a preformer apparatus 2 comprising ground engaging supports 4, a hood 6 which extends between the ground engaging supports 4 to which it is movably mounted, and a diaphragm frame 8 that is adapted to receive and hold a diaphragm (not shown) which spans across the interior space defined by the diaphragm frame 8.

Ground engaging supports 4 are counterbalanced. This allows the preformer apparatus to be free-standing without any requirement to be affixed to a floor.

Diaphragm frame 8 is mountable to hood 6 by a plurality of shafts 12.

In one embodiment of the invention, the diaphragm frame is suspended from hood 6 by shafts 12 which are connected to the hood via bushings (not shown). In this embodiment, when hood 6 is fully raised, diaphragm frame 8 is suspended below the hood with shafts 12 fully extended from the hood. In this way, the diaphragm frame is extensible from and to the hood. ln operation, downward motion of hood 6 lowers diaphragm frame 8 into place onto a table 14 which is adapted to support a forming tool 90 and which is situated in use in the space between the ground engaging supports 4 and generally below the hood 6. In this way, the weight of the diaphragm frame 8 provides a seal around the table 14 which it contacts in use. This sealing contact may be augmented by the force of the hood 6 when it is further lowered (as described below) onto the diaphragm frame already seated on the table, whereby the shafts will have generally retracted upwardly into the hood 6. Subsequent raising of hood 6 causes the shafts 12 to extend from the hood which enables the diaphragm frame 8 to remain on the table. The diaphragm frame 8 will remain on table 14 until the shafts 12 reach their full downward stroke, after which further raising of the hood 6 causes the shafts 12 to lift the diaphragm frame 8 from the table surface. in this way, the hood and diaphragm frame can be raised and lowered with respect to the table.

In an alternative embodiment, at least one shaft 12 is motor driven so that diaphragm frame 8 is independently movable relative to the hood. Actuation of the at least one motor driven shaft or shafts 12 causes the diaphragm 8 to extend from or retract towards hood. Conveniently, the diaphragm frame is thereby driven into place onto a table 14 which is situated in use in the space between the ground engaging supports 4 and generally below hood 6. In this way, the downwards forces exerted by the at least one motor driven shaft or shafts 12 upon diaphragm frame 8 force the frame tightly against table 14 which it contacts in use.

Referring to Figure 3, hood 6 is mounted to ground engaging supports 4 by guide means comprising a plurality of shafts 16 along which the hood 6 is vertically movable. Hood 6 is vertically translated along the shafts by means of one or more ballscrews 18. Ideally, the or each ballscrew 18 is servo motor controlled (not shown). Where more than one ballscrew is provided, the respective ballscrew motors are synchronised by a controller [not shown). In this way, the hood can be quickly and accurately positioned and is maintained in correct horizontal alignment throughout vertical upward and downward travel. The or each ballscrew may comprise a dual row ballscrew, comprising a 20 to 1 gearing ratio gear box 22 which has advantageously been found to prevent the hood 6 from creeping' downwards.

As shown in Figures 1 and 2, a covering 19 to conceal and protect shafts 16 and ballscrews 18 is provided.

In a preferred embodiment, the or each ballscrew servo motor is provided with motion control means 24 which prevents hood 6 travel overshoot and applies braking if overrun is detected.

Hood 6 is further provided with a mechanical brake 26 (Figure 3) which is operable to stop and maintain the hood in position when power to the prefromer apparatus is interrupted.

Referring to Figure 4, hood 6 and/or its guide means is further provided with a part detection system 28 which is operable to detect the presence of an obstacle as hood 6 is being lowered, the detection system preferably comprising a limit switch 30 which operates on a floating plate 32 which carries the weight of hood 6. In this way, if the hood is lowered onto a part or object, the floating plate 32 will detect the contact with the obstruction and the travel of the hood 6 will be stopped.

Conveniently, this protects tools and the hood from being damaged.

As shown in Figure 2, in which the hood is shown without its outer covering, hood 6 1 0 comprises a latticed superstructure 61 that is adapted to support the weight of the hood, to provide rigidity and to mitigate bending or twisting moments. Conveniently, superstructure 61 further provides means to house and support heating means (not shown) and an air extraction system 70 as well as the diaphragm frame 8.

Referring to Figure 5, diaphragm frame 8 comprises an integrated seal 82 on its underside (i.e. table engaging surface) which is adopted to form a sealing contact with the table 14 which it abuts in use. Ideally, integrated seal 82 is a high profile seal. Integrated seal 82 is an elongate seal comprising at least first and second limbs, 83, 84 respectively. The first limb 83 is affixable to the underside of the diaphragm frame 8, the second limb 82 being a free limb extending from the first limb such that the seal is compressible. In this way, when vacuum is applied, the diaphragm frame 8 may be drawn more tightly against the table 14. The angle defined between the first 83 and second limbs 84 of the integrated seal 82 is less than 900. In this way, the integrated seal 82 substantially resembles a 7' shape in section.

The provision of integrated seal 82 ensures vacuum integrity with the surface of table 14 thereby obviating the need for providing specially adapted machined surfaces and/or the use of seal compounds on the table 14 and/or diaphragm frame 8 to achieve an effective seal therebetween. In use, the seal strength increases in proportion with vacuum strength. The provision of integrated seal 82 and the motor driven diaphragm frame 8 obviates the need for separate or further clamping means to be used to hold the hood to the table to create a vacuum seal as would otherwise

be the case with prior art preformers.

The ability of the hood 6 to be raised from, or lowered proximate to, diaphragm frames and the diaphragm (not shown in the Figures) when they are in sealing engagement with a table 14 and a tool 90 (Figure 1), or tools thereon, respectively, enables a vacuum seal to be established and maintained between the diaphragm and the tool or tools 90 while allowing visual inspection of the tool(s), table 6 and the composite part(s) being formed throughout the forming process. This obviates the need to provide windows in the hood for visibility into the apparatus and provides an operator with both visual and physical access to inspect parts being formed.

The independently movable diaphragm frame 8 allows variable table 14 heights to be used with the preformer apparatus. Whilst it is envisaged that the present preformer can readily accommodate tables in the height range of 300 mm to 1400 mm, the apparatus is not limited in size for it can readily be scaled up or down. The capability of the preformer apparatus to accommodate a range of table heights in turn allows tools of significant height profile to be used and large parts (e.g. aircraft fuselage sections, wing spars, nacelles, cowlings) or curved or stepped parts to be formed.

Referring to Figure 5, diaphragm frame 8 comprises upper 85 and lower 86 in use sections, the lower section 86 being separably demountable from the upper section so that the frame may clamp a diaphragm 100 which it receives and holds, In Figure 5 an edge of a diaphragm 100 is schematically represented by a dashed line.

The respective upper 85 and lower 86 in use sections are each provided with complementary formations 87, 88 which engage with the margins of a diaphragm to be clamped when the said respective sections of the frame are fastened together by suitable releasable fastening means 800, such as a threaded rod or turnbuckle.

Conveniently, a deformable bead 89 may be inserted in a space defined between the upper 85 and lower 86 in use sections of the diaphragm frame 8 to augment the clamping of the diaphragm to the diaphragm frame. Such a means to receive and hold a diaphragm provides the apparatus with the capability to enabling up to 20m of diaphragm material to be replaced by two operators within 30 minutes.

Advantageously, the diaphragm clamping system enables diaphragm tension to be readily adjusted which is effected by unscrewing or opening the fastening means 800 partially so that diaphragm frame 8 is opened sufficiently to allow an operator to pull a required amount of diaphragm through.

Referring also to Figure 5, in another aspect of the invention there is shown a table 14 having a porous layer 141 provided below a working surface 142, the porous layer preferably comprising a porous foam though which air from the region below the diaphragm is evacuated, the air having first being vented through a plurality of apertures (not shown) in working surface 142. The provision of such a porous layer between the table's base 14 and its working surface 142 ensures that an even vacuum is distributed across the working surface in use. A load bearing peripheral band 143 overlaps the peripheral edge of porous layer 141 and working surface 142.

As shown in Figures 3, 6 and 7, at least one of the ground engaging supports 4 is provided with means to receive and store a supply of diaphragm material 100 which can be dispensed to the diaphragm frame (not shown). Generally the diaphragm material 100 is delivered to the apparatus in the form of a roll. The means to receive the supply of diaphragm material 100 generally comprises a pair of bearings 102 adapted to receive an axle 104 extending through the diaphragm material 100 which is presented as a roll as described above. A hand operated wheel 106 mountable to one end of axle 104 allows the roll to be turned and diaphragm material to be dispensed to the diaphragm frame. As an alternative to hand wheel 106 a motor may be provided. Space in the ground engaging support 4 is provided to enable the forks or tines 108 of a forklift or other suitable delivery means to deposit the roll onto bearings 102.

As shown in Figures Band 9, in a further aspect of the invention, the preformer apparatus further comprises trolley guide means 110 to ensure that tables 14 in the form of movable trolleys 112 are accurately locatable within the space between the ground engaging supports 4 and generally below the hood (not shown). The guide means, indicated generally by reference numeral 110, comprises a pair of spaced apart rollers 114 which are mounted to at least one ground engaging support 4.

Rollers 114 may be mounted directly to supports 4 or via a suitable intermediate structure 116 which provides additional clearance between the trolley 112 and said support 4. Rollers 114 act as a receiving means which guide a trolley 112, by means of a complementary member 118 provided on said trolley, into a correctly aligned position within the apparatus. Member 118 comprises a generally triangular shape.

The convergent sides 118a of member 118 enable the member to generally move towards, and subsequently into, the gap between rollers 114 during initial positioning as shown in Figure 8. When correctly and fully seated, the respective convergent sides 118a of member 118 will each be in contact with a roller 114 as shown in Figure 9. When correct seating is achieved, trolley 112, and thus table 14, will be in accurate longitudinal and transverse alignment with the preformer apparatus. Being able to accurately locate the table 14 within the performer apparatus advantageously ensures repeatability of positioning tools and parts within the apparatus. This in turn means that like parts may be consistently formed under the same conditions and parameters.

Although not visible in the Figures, hood 6 further comprises on its interior surface heat sources in the form of a plurality of fast response medium wave infrared emitters which are tuneable to their frequency of the carbon fibre of the layup or pre-preg being formed. These ensure that maximum energy is absorbed by the layup or pre-preg to be formed. Such infrared emitters enable the carbon surface temperature of the part to be formed to 115°C within 15 minutes of operation. In addition, the infrared emitters have capability to penetrate through a 10mm depth of carbon fibre within 10 minutes of operation, thereby improving heating rates and reducing energy costs.

Advantageously, the infrared emitters are mounted on electrically actuated adjustable mountings (not shown] to provide optimum angle and position relative to specific parts to be formed.

In a further aspect of the invention not visible in the Figures, the prefo rmer apparatus is provided with a multizone control system for control over the infrared emitters such that complex tool shapes can be maintained within the apparatus at uniform temperature. The provision of a multi zone control system for control over the infrared emitters also enables the apparatus to be operated at full capacity whereby a plurality of tools can occupy the table so that all available space is used, the multizone control system enabling specifically tailored heat profiles or energy emission to be applied simultaneously to specific parts being formed on the separate tools, i.e. each part on the table occupying a defined zone that is separately heated according to its own specific requirements.

In a preferred arrangement, the infrared emitters are arranged in banks, each bank being adjustable about two planes to enable heat to be directed evenly across multiple zones and which ensures minimal cross-over of heat between said zones as well as uniform heating across complex shaped parts being formed.

Although not visible in the Figures, the hood further comprises on an interior surface a plurality of high temperature pyrometers which enable non-contact temperature control. In conjunction with the multizone control system, the provision of high temperature pyrometers ensures that the infrared heating elements in each zone are accurately controlled so as to apply correct heat profiles to any one of the variety of shapes and sizes of component which may be formed on the table simultaneously with each zone being separately temperature controlled.

The provision of high temperature pyrometers provides precision non-contact temperature control means which obviates the need for control thermocouples to be positioned by an operator. The pyrometers may be provided on adjustable mountings enabling operation at a multitude of angles thereby ensuring their placement is generally central relative to the parts being monitored. In this way, optimum temperature control is possible. Ideally, the adjustable mountings comprise an adjustable ring provided under the pyrometers which enables an operator to direct the pyrometer without moving any covers on the part being formed or without the breaking the vacuum seal.

A laser may also be provided on each pyrometer to enable positioning of each pyrometer to be more readily achieved. In this way, a blue print' of the machine configuration for specific tools or parts to be formed can be recorded and stored on a memory.

In a preferred arrangement not visible in the Figures, the preformer apparatus is provided with embedded tool thermocouples which can be monitored to ensure that the carbon materials being formed are maintained within correct temperature specifications. This prevents carbon scorching or drying out of binder or matrix materials.

With reference to Figures lOa, lOb and lOc, in a further aspect of the invention, the preformer is provided with means to dispense an insulation material 92 adapted to augment the heating of a composite layups or pre-pregs 94 during forming while at the same time preventing excessive heating of the base(s) of the forming tool(s). The means to dispense the insulation material comprises a motorized winch assembly 95 (Figures lOa and lOb) provided at one end of the hood 6, the winch assembly further comprising a.cable 96 adapted to draw the insulation 92 material from a suitable dispenser (not shown) arranged at the opposing end of the hood 6, so that the insulation material 92 is drawn at least partially across the width of the hood 6 in use. In a preferred embodiment, the insulation material dispenser is adapted to retract the insulation material away from the winch assembly 95 and return it to said dispenser. Preferably, the insulation material 92 is a foil-backed insulation material. Preferably the foil-backed insulation material supplied in the form of a roll.

The use of an insulation material 92 is described with reference to an exemplary U-shaped forming tool 97. For clarity, no diaphragm or table is shown in Figures lOb, lOb and lOc. Once the diaphragm is vacuum sealed over the tool 97 and pre-preg(s) 94 placed thereon, and before a heat cycle commences, an elongate sheet of insulation material 92 is drawn from a dispenser (not shown) by motorized winch which is coupled to said insulation material via cable 96. In use, the insulation material extends generally across and/or through the space of the tool 97 such that excessive heating of the base 97a (Figure lOc) of the tool is mitigated and that infra-red radiation from the emitters (not shown) is reflected off a foil surface of the insulation material and back in the direction of the pre-preg(s) 94 located above. In this way, a improved heat-up time is achieved with reduced energy expended. After a heat cycle is completed the insulation material can be wound back to its dispenser to allow heat to dissipate as quickly as possible. In this way, an improved cooling time is achieved as the tool base is maintained at a lower temperature resulting in a reduced thermal mass to cool. In this way, cycle time optimised.

Other inventive and advantageous features of the preformer apparatus in accordance with the present invention include: * Fixed overtemperature thermocouple rods provided within the hood to act as secondary safety system. These rods measure air temperature to remove all energy from the preformer system in case of extreme temperatures.

* Materials used in the preformer apparatus being able to withstand temperatures up to 232°C.

* Vacuum-tight table adapted to accommodate multiple tool thermocouples, typically 60 thermocouples for a machine of 20m length.

* 6-way connectors to make it impossible to connect the multiple tool thermocouples into the wrong place.

* The thermocouple connections being under-slung thereby providing a flat uncluttered working surface for tools and materials on the working area on

the table top.

* Multiple vacuum outlets providing vacuum, within 4OmBar absolute, across entire surface area. Capability to pull vacuum to -900mBar (lOOmBarAJ within 1 minute by use of microporous material under the table surface, to allow air to escape quickly. Provision also of veins at intervals across the apparatus and shower heads' where the vacuum enters the table surface.

* High flow and large vacuum storage ensuring rapid pull-down of vacuum.

* Vacuum pumps having three times the flow rate of know preformer machines. A large accumulator and 100mm bore pipework is also fully charged to give a sudden snap' of vacuum, This is important to prevent product slippage on top of the tools.

* Silicon heat seal ensures no loss of heat and no air flow during process.

* A 40mm tall heat seal in the hood area between the membrane and the infrared emitters to prevent convection.

* Sealing systems and extremely low U-value thermal insulation to ensure the heat energy remains within the hood in use.

* Automated damper valves which open at the end of the heating cycle to allow for rapid cooling. At this stage convection is used to draw the hot air away from the tools.

* High flow air extraction system capable of cooling 2 tonnes of tooling to 4OdegC within 40 mins.

* A balanced pressure system, with active temperature feedback to ensure the cooling rate is maintained at the optimum rate without shocking tools and causing stress fractures.

* Negative pressure cooling system to ensure no contamination of clean room during cooling.

* Compatibility for use in a clean room environment due to the non-presence of greases, lubricants or air mist being dispersed to atmosphere. Due to excellent sealing systems, there will be no adverse effect on local HVAC systems.

* Electrical control panels are pressurised with clean dry air to ensure the electronic components are not contaminated with carbon fragments.

* Provision of Cimplicity HMI SCADA system offers clear graphical prompts to operator.

* All historical data is recorded and stored on a network server.

* All information required for FAA assurance is available immediately after cure cycle.

* The data stored would include operator, cure details, parts loaded, etc. * SPC data is also stored to detect machine fluctuations and offer early diagnosis of potential problems.

* The angle and height of each heater is adjusted by an electric actuator to offer optimum angle and position for each part being preformed.

* Foil backed insulation material is laid along full length of machine by electric winder. This is to reduce tool temperature and optimise cycle time.

* Foil backed insulation is removed by electric winder at beginning of cooling cycle. This is to maximise surface area for cooling air and optimise cycle time.

* Chilled air is recycled as it exits the preformer, to double volume of cooling air and reduce cycle time.

Various modifications and variations to the described embodiments of the invention will be apparent to those skilled in the art without departing from the scope of the invention as defined in the appended claims. Although the invention has been described in connection with specific preferred embodiments, it should be understood hat the invention as claimed should not be unduly limited to such specific embodiments.

Claims

Claims 1. A preformer apparatus comprising one or more ground engaging supports, a hood, and a diaphragm frame that is adapted to receive and hold a diaphragm, wherein the hood is movably mounted to the ground engaging supports between which it extends, and wherein the diaphragm frame is mounted to the hood from which it is independently movable.
2. A preformer apparatus as claimed in claim 1, wherein the diaphragm frame is mounted to the hood via a plurality of shafts.
3. A preformer apparatus as claimed in claim 2, wherein the diaphragm frame is suspended from the hood by the shafts which are mounted to the hood via bushings so that when the hood is fully raised, the diaphragm frame is suspended is below the hood with the shafts extended from the hood.
4. A preformer apparatus as claimed in any preceding claim, wherein downward motIon of the hood lowers the diaphragm frame into place onto a table which is adapted to support a forming tool and which is situated in use in the space between the ground engaging supports, the weight of the diaphragm frame providing a seal around the table which it contacts in use.
5. A preformer apparatus as claimed in claim 4, wherein further downward motion of the hood causes the hood to contact and press downwardly against the diaphragm frame seated on the table in use.
6. A preformer apparatus as claimed in any preceding claim, wherein the ground engaging supports are counterbalanced.
7. A preformer apparatus as claimed in any preceding claim, wherein the hood is mounted to the ground engaging supports by guide means comprising a plurality of shafts along which the hood is vertically movable.
8. A preformer apparatus as claimed in claim 7, wherein the hood is vertically translatable along the shafts by means of one or more ballscrews.
9. A preformer apparatus as claimed in claim 8, wherein the or each ballscrew comprises a dual row balls crew.
10. A preformer apparatus as claimed in claim 7 or claim 8, wherein the or each ballscrew is servo motor controlled and is provided with motion control means which prevents hood travel overshoot and applies braking if overrun is detected.
11. A preformer apparatus as claimed in any preceding claim, wherein the hood is provided with a mechanical brake operable to stop and maintain the hood in position when power to the prefromer apparatus is interrupted.
12. A preformer apparatus as claimed in claim 11, wherein the hood is further provided with a part detection system operable to detect the presence of an obstacle as the hood is being lowered and is operable to prevent further lowering of the hood when an obstacle is detected.
13. A preformer apparatus as claimed in claim 12, wherein the part detection system comprises a limit switch operable on a floating plate which carries the weight of the hood.
14. A preformer apparatus as claimed in any preceding claim, wherein the diaphragm frame comprises an integrated seal on its underside which is adapted to make sealing contact with a table which it abuts in use.
15. A preformer apparatus as claimed in claim 14, wherein the integrated seal is an elongate seal comprising at least a first and second limb, the first limb being affixable to the underside of the diaphragm frame, the second limb being a free limb extending from the first limb such that the seal is compressible.
16. A preformer apparatus as claimed in claim 15, wherein the angle defined between the first and second limbs of the integrated seal is less than 900.
17. A preformer apparatus as claimed in any preceding claim, wherein the diaphragm frame comprises upper and lower in use sections, the lower section being separably demountable from the upper section so that the frame is operable to clamp a diaphragm which it receives and holds.
18. A preformer apparatus as claimed in claim 17, wherein the respective upper and lower in use sections are each provided with complementary formations which engage with the margins of a diaphragm to be clamped when said respective sections of the frame are fastened together by suitable releasable fastening means.
19. A preformer apparatus as claimed in claim 18, wherein a space defined between the upper and lower in use sections of the diaphragm frame is adapted to recefive a deformable bead to augment the clamping of the diaphragm to the is diaphragm frame.
20. A preformer apparatus as claimed in any preceding claim, wherein at least one of the ground engaging supports is provided with means to receive and store a supply of diaphragm material which can be dispensed to the diaphragm frame.
21. A preformer apparatus as claimed in any preceding claim, wherein the hood further comprises heat sources in the form of a plurality of fast response medium wave infrared emitters.
22. A preformer apparatus as claimed in claim 21, wherein the infrared emitters are mounted on electrically actuated adjustable mountings to provide optimum angle and positioning relative to specific parts to be formed.
23. A preformer apparatus as claimed in claim 22, wherein the preforrner apparatus is provided with a multizone control system for control over the infrared emitters such that complex tool shapes can be maintained at uniform temperature within the apparatus.
24. A preformer apparatus as claimed in claim 22 or in claim 23, wherein the infrared emitters are arranged in banks, each bank being adjustable about at least two planes to enable heat to be directed evenly across multiple zones and which ensures minimal cross-over of heat between said zones as well as uniform heating across complex shaped parts being formed.
25. A preformer apparatus as claimed in any preceding claim, wherein the hood further comprises a plurality of high temperature pyrometers.
26. A preformer apparatus as claimed in claims 25, wherein the pyrometers are provided on adjustable mountings to enable them to be operative at a multitude of angles thereby ensuring their respective placement is generally central relative to the parts being monitored.
27. A preformer apparatus as claimed in any preceding claim, wherein the preformer is provided with embedded tool thermocouples.
28. A preformer apparatus as claimed in any preceding claim, wherein the preformer is provided with means to dispense an insulation material, the means comprising a motorized winch assembly provided at one end of the hood, the winch assembly further comprising a cable adapted to draw the insulation material from a suitable dispenser arranged at the opposing end of the hood, so that the insulation material can be drawn at least partially across the width of the hood in use.
29. A preformer apparatus as claimed in any preceding claim, wherein the preformer apparatus further comprises guide means to accurately locate tables within the space between the ground engaging supports and generally below the hood.
30. A preformer apparatus as claimed in claim 29, wherein the guide means comprises a pair of spaced apart rollers which are mounted to at least one ground engaging support, the adapted to receive a complementary member provided on a said table so that the table is guided into a correctly aligned position within the apparatus.
31. A table for use in an preformer apparatus as claimed in claim 30, wherein the complimentary member provided on said table comprises a generally triangular shape having convergent sides to enable the member to generally move towards, and subsequently into, the gap between the spaced apart rollers of the guide means during initial positioning.
32. A preformer apparatus as herein described with reference to the accompanying drawings.