Background

The present invention is concerned with an apparatus for improving the reliability of component production where a curing process is used. Specifically, but not exclusively, the apparatus is concerned with the production of parts using an out-of-autoclave curing process. Such a process can be used to manufacture carbon fibre reinforced plastic materials as one example.

Carbon fibre reinforced plastic (CFRP) components are frequently used where strength and weight are desired component properties. A series of carbon fibre fabric layers and resin are laid over a mould to form a desired shape. The resin is then cured over a predetermined period of time to harden such that the carbon fibres in the fabric are encapsulated in resin. Once cured a hard and rigid part is formed. Such components are often referred generally to composite parts.

Curing can be achieved using heat and pressure using an oven or autoclave. Alternatively, as with the present invention the curing step of the manufacturing process can be performed without an autoclave at ambient pressure. The temperature and humidity of the environment can then be controlled to aid the curing process. This process is known in the art as Out-Of- Autoclave (OOA) curing.

In a conventional arrangement, the fabric layers are laid over or into a mould and the mould is then left to cure. After a predetermined period of time the component is ready to be removed from the mould for final machining/use.

OOA curing allows components to be manufactured without the expense of autoclave use. However, without the use of an autoclave the curing conditions are difficult to monitor and control and disparities in curing can occur as ambient conditions change. This can result in subtle differences in the integrity of the cured components. In most applications any such disparities are inconsequential and are not detrimental to the performance of the part. However, in the aerospace industry components must conform to strict requirements. This has led to frequent use of autoclave curing where the conditions can be controlled. This, in turn increases the cost of manufacturing composite parts. The inventors have devised an alternative approach to OOA curing which ensures conformance to curing conditions, reduces non-compliant parts and reduces cost. It also allows large volumes of components to be manufactured with low labour costs. The disclosure herein is also intended to include other examples of curing processes, such as sealant, adhesive or paint cures that occur outside of an autoclave. In these processes, the substance is applied to the parts as part of their manufacturing process and the substance must be allowed to cure in controlled conditions before the next manufacturing operation. The present invention is directed to such processes in the context of ensuring conformance to a prescribed curing process and conditions.

Summary of the Invention

Aspects of the invention are set out in the accompanying claims.

Viewed from a first aspect there is provided a cure apparatus comprising a plurality of part detectors each arranged to detect the presence of a part to be cured proximate to the detector, the apparatus comprising one or more visual display arrangements associated with each detector and a control arrangement, wherein the control arrangement is arranged in use to receive cure parameter information in respect of a part and to display cure information relating to the part on a display associated with that part.

Thus, according to an invention described herein a curing apparatus can automatically determine if a part to be cured has been placed in a predetermined curing position i.e. proximate to a sensor. Depending on whether a part has been placed in position, information about the cure can be received and displayed for an operative to view. The operative can then conveniently and easily see information about the cure of each part.

The cure information may for example indicate if a part is in the correct position, if the cure is complete and/or if the cure in ongoing. It may also provide information relating to any cure problems determined by the detector or sensor.

The apparatus may be in the form of a plurality of levels forming a curing rack. Thus, large numbers of components can be positioned close together to provide a high density of components. This means large numbers of components can be cured in a small area.

The detectors may be arranged in a predetermined pattern or array to optimise the space used. The detectors may also be adapted so that they can be moved on the surfaces to accommodate different sized components.

Advantageously, the cure parameter information may include the time required to cure the part and the displayed cure information may be information indicating if the cure time has elapsed. An operative can quickly determine the curing progress for each part.

The detector may also be arranged in use to detect attributes of a part allowing the part to be identified. Thus, further information can be derived by determining which parts are to be cured in a given cure cycle. For, example the detector may be a proximity detector arranged in use to detect the proximity of a part to the sensor. By knowing the position of the part relative to the detector and know the geometry of the part it is possible to establish what the part is. Specific information can then be obtained about the curing of that part. The detector could alternatively be a pressure sensor or the like arranged to determine the shape of ‘footprint’ of the part. Again, the specific part can then be identified. This allows any incorrect or erroneous parts for a given cure cycle to be identified before the cure commences. In some embodiments, the detector may be a load cell arranged in use to detect the weight of a part.

The plurality of detectors may each be provided with a local controller arranged to communicate with the control arrangement and to request cure information in respect of the detected part. As discussed above this advantageously allows specific and relevant information to be requested. In effect the detector has its own processor for determining the component and requesting information from a central or master controller which itself has access to part curing data. Only data relating to the specific part need be communicated to the local controller.

The master controller may be arranged to control all of the displays. Alternatively, each local controller may be arranged in use to control the information displayed on the display associated with that part. A local detector, controller and display is thereby provided.

The cure parameter information may include environment parameters and limits relating to a part to be cured. For example, the cure information may indicate that for an aerospace wing component the cure must be performed within +- 5 degrees of 25 degrees C, and within +- 5% of 50% relative humidity, for a period of between 23 and 25 hours. In some embodiments, the cure information may indicate that the cure must be performed for a cure period in excess of 24 hours.

The environmental parameters may include specific temperature and/or humidity ranges and combinations within which a part can be successfully cured. This allows accurate determinations to be made as to whether a cure has been successful and if the cure has been performed within agreed manufacturing tolerances. This is particularly important in the aerospace industry. Advantageously, the control arrangement may be configured or arranged to output control signals to control environmental apparatus proximate to the cure apparatus. Thus, the following sequence can be realised:

Identify the part

Identify the curing parameters/limits/ranges

Identify the environmental conditions and compare those with the ranges; and

Output control signals which can be used to control the environmental conditions around the curing apparatus.

Thus, a feedback loop can be realised in which curing can be monitored and controlled for an out of autoclave curing system.

For example, the control apparatus may be arranged to output temperature and or humidity control signals for receipt by an air-conditioning/heating apparatus and a humidifier/de humidifier respectively. Each can then be controlled to prevent a failed cure.

The one or more visual display arrangements may be in the form of a visual display proximate to an associated detector. This could be a simple cluster of LED lights indicating curing, not curing or no part for example. It could also be a small screen indicating remaining cure time, parameters, and coloured indicators allowing for a simply and efficient visual inspection of the rack. For example, if all is within limits the screens may show green. Red could indicate a failed cure and a flashing indicator a problem.

Alternatively, the one or more visual display arrangements could be in the form of a graphical user interface remote from the cure apparatus. This could be in a separate room from the curing room, on a mobile computing device or on a mobile phone. This would allow the operative to move around a site and receive warning indications if any issues occur.

The control arrangements may also be configured to predict curing problems. This may advantageously allow an operative to intervene in a cure process to prevent the loss of a component.

Specifically, the control arrangement may be arranged in use to: receive time related data relating to the local environment of the cure apparatus;

extrapolate the data;

compare the extrapolated data against environmental limit data; and output data indicating if and optionally when the limit will be reached.

Extrapolating data allows the predictions to be made against predetermined limits.

Cures may also fail if certain parameters are breached for an excessive amount of time. Thus, the control arrangement may be further arranged to indicate if environmental limits have been exceeded for a predetermined period of time to the operative.

In another arrangement of an invention described herein the cure apparatus may further comprise an induction charging arrangement and battery arranged such that the battery can be charged when the curing apparatus is proximate to an associated induction coil or arrangement. This allows the curing rack to be conveniently moved around to allow a group of parts to be moved and to be charged in a specific location. The controllers may be on board the rack and a battery, charged through induction, used to power the detectors, displays and controllers.

In accordance with some embodiments, the cure apparatus may comprise a plurality of stops for positioning each part to be cured with respect to the detector which is arranged to detect the presence of the part. Such stops may thus allow more accurate positioning of each part with respect to its associated detector. In some particular embodiments, the stops may be rubber stops to better prevent any damage to the part whilst the stops are in use.

In some embodiments, the apparatus may comprise a plurality of wheels for moving/wheeling the apparatus along the ground.

In some particular embodiments, the cure apparatus may comprise a cure rack comprising a plurality of levels for supporting the plurality of part detectors and the one or more visual display arrangements. With the provision of such levels, this may facilitate easier access to the plurality of part detectors, and easier visibility of the one or more visual display arrangements which are supported by the levels. Where the cure rack comprises the plurality of levels, the plurality of levels in some particular embodiments may comprise a first level and a second level located above the first level; wherein the first level comprises a first portion of the plurality of part detectors and a first portion of the visual display arrangements; and wherein the second level comprises a second portion of the plurality of part detectors and a second portion of the visual display arrangements. In this particular embodiment, the provision of such first and second levels can provide for a more efficient use of space by the cure rack, and can allow the various cured parts as well as the visual display arrangements to be more effectively separated from each other about the respective levels from the cure rack.

Viewed from another aspect there is provided a method of curing components comprising the steps of

Identifying a part to be cured;

Identifying the curing parameters/limits/ranges of the part - Identifying the environmental conditions and comparing those with the ranges; and

Outputting control signals which can be used to control environmental conditions around the curing apparatus.

Drawings

Aspects of the invention will now be described, by way of example only, with reference to the accompanying figures in which:

Figure 1 shows a detector and part, such as an aerospace part, to be cured;

Figure 2 shows a cross-section through a detector and part;

Figures 3A to 3C show different components and detector examples;

Figure 4 shows a plurality of detectors in a curing rack arrangement;

Figure 5 shows data communication lines between detectors and displays;

Figure 6 shows a curing room and environmental controls;

Figure 7 shows a graph of time and humidity and associated limits;

Figure 8 shows a cure rack with a range of cure parts; and

Figure 9 shows an induction charging arrangement for a curing apparatus described herein.

Figure 10 show a flow chart illustrating an example operation of a cure rack/apparatus described herein.

While the invention is susceptible to various modifications and alternative forms, specific embodiments are shown by way of example in the drawings and are herein described in detail. It should be understood however that drawings and detailed description attached hereto are not intended to limit the invention to the particular form disclosed but rather the invention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the claimed invention

It will be recognised that the features of the aspects of the invention(s) described herein can conveniently and interchangeably be used in any suitable combination. It will also be recognised that the invention covers not only individual embodiments but also combinations of the embodiments that have been discussed herein. Detailed Description

Figure 1 shows an example composite part 1. The composite part 1 is formed of a plurality of layers 2 which are each arranged at specific angles relative to one another.

The concept of laying up a stack of layers of carbon fibre (or other) layers over a mould 3 is well known in the art of composite manufacturing and will not be described in detail herein. The mould 3 acts to support the flexible layers 2 during the curing process. The curing process involves a resin that is applied to each of the layers (or alternatively impregnated into the fabric) hardening over a predetermined period of time and under predetermined conditions.

In the example shown in figure 1 a curved component is illustrated which may, for example, be an aerodynamic component for an aircraft or a light cluster for an aircraft wing.

The component or part 1 is position on a surface 4 to support the part during the curing process. An aspect of an invention described herein comprises a sensor 5 which detects one or more attributes of the part to be cured. The sensor is located proximate to the part and arranged in use to detect, for example, that a part is in proximity to the sensor. This thereby determines that a part to be cured is present in or on the curing apparatus described herein. The sensor may send and receive data and power through an electrical connection 6 described in more detail below.

Figure 2 illustrates the sensor 5 in more detail in. The sensor may be selected from a range of sensing or detecting devices. For example the sensor may be a proximity sensor 5a which detects the proximity of the component 2 to the sensor as illustrated by distance d. If an object is detected within distance d then it may be determined that a component or part is in position for a cure.

One example of a proximity sensor is a GP2Y0A710K0F manufactured by SHARP of Japan.

The sensor 5a may detect the simple presence of a component 2 and return a positive signal via an electrical (or other) channel 6. In an alternative arrangement the distance d (the proximity) may be used to determine particular attributes of the component which is proximate to the sensor. This is illustrated with reference to figures 3A to 3C. In each of figures 3A to 3C a different part is located proximate to the sensor. In each case the distance d may be used to determine the component which is proximate to the sensor (by placing the component in a predetermined position with respect to the sensor; for example in a suitable jig or holding arrangement).

In figure 3A the distance di determines a first part which can be identified as part A. Similarly in figure 3B a different distance d2 is measured indicating a different part B. The distance measured may be in any suitable direction and orientation with respect to the surface 4. For example in figure 3C the distance d3 is measured horizontally identifying part C.

It will be recognised that a combination of sensors may be used to identify the part. This information or data may be used as part of the cure process as described in more detail below.

Returning to figure 2, an alternative sensor 7 is shown. Here the forces F1 and F2 are used to detect the presence of the component and further to identify the type of component which has been placed on the surface 4. In effect sensor 7 may be a transducer of some kind detecting the force the component applies at different locations i.e. the components ‘footprint’.

It can thus be seen that the curing apparatus described herein may not only detect that a component is in position for curing but it may also determine which type of component is to be cured. It will of course be recognised that other detecting means could be used such as cameras or other optical detector.

As will be described in further detail below, this determination from the curing apparatus can be used in a range of advantageous ways.

For example, aspects of the curing environment may be controlled and/or monitored in response to the specific components which are to be cured. In addition, the desired cure time can also be determined and determinations of successful or successful cures can also be conveniently made. Still further, predictions of the success or lack of can also be made using information gathered by the apparatus in conjunction with the information described above.

Figure 4 shows a curing rack apparatus 8 according to an invention described herein. The rack 8 comprises a series of support surfaces 9 onto which a plurality of sensors 5 may be positioned. The sensors 5 correspond to the sensors described above with reference to figures 1 to 3C.

As shown each surface comprises an array of sensors, each sensor being arranged and spaced so as to allow parts that are to be cured to be positioned adjacent to one another (not shown in figure 4). It will be recognised that different components may be cured adjacent to each other or on different support surfaces 9.

Figure 5 illustrates the array in more detail. As shown each array comprises a plurality of sensors 5. Each of the sensors may also be conveniently connected to a data bus or power supply 10 which allows for power to be supplied to each sensor and also allows for data communication between the sensor and a master controller 11. The master controller may be part of the rack 8 or may be remote from the rack allowing for remote monitoring of the curing processes.

The rack 8 may also be provided with one or more visual displays 12 which may display information or indications in respect of a proximate sensor 5. For example sensor 5A may be associated with display 12A and sensor 5B associated with sensor 12B. There is thereby provided a display associated with one or more sensors.

The display may be part of the rack allowing for convenient visual inspection of the rack or the display may also be remote and associated with the master controlled 11 (or a combination of both).

The display 12 may be a simple light indicating system with one or more colours or indicating lights to provide information to an operative about the cure. In a simple form the display may be in the form of a 3 light or 3 colour indicator indicating one of:

Cure Complete

Cure Incomplete

Cure Error

No Part Present For instance, in one embodiment, for indicating the‘No Part Present’ status, the 3 lights may all be turned off. For indicating the‘Cure Complete’ status, the 3 lights may all be turned on.

Thus an operative can very quickly visually inspect the curing apparatus to determine the status of each cured part.

In operation the operative can load the rack with a plurality of parts and activate the rack such that each sensor can determine if a component is in position. It can then begin a timer which counts to a predetermined time before changing the indicator as described above.

The time may be uniform for each location on the apparatus but advantageously by determining what the part is an individual time can be set. The timing details may be retrieved from a database associated with the master controller and communicated to the display.

The display could alternatively be in the form of a graphical user interface on a computer, tablet or other mobile device. A remote operative could then see the same information remotely from the curing apparatus.

The automatic determination of the part being cured provides other advantages. For example, by determining the part to be cured the optimal curing conditions can be retrieved from a database. This may include time and also maximum curing temperature and humidity. It may also determine the curing time in response to the conditions where the rack is positioned. For example the rack may comprise temperature and or humidity detectors and this data can be processed by the master controller to determine the cure time for those conditions. This can then be used to operate the display as described above.

The environment conditions may also be controlled as shown with reference to figure 6. The cure apparatus 8 is positioned in a curing room 13 which comprises an air conditioner 14 and humidifier/dehumidifier 15. The rack determines through sensors 5 associated with parts 2 what the curing conditions or ranges should be. Once curing has commenced the master controller 11 may selectively control the temperature and humidity of the room 13 to be within predetermined ranges by communicating signals 16 to the air conditioning and humidifier/de humidifier. Continuous or intermittent monitoring of the environment within the room can indicate if a part has not been cured within the predetermined ranges and this can then be used to indicate to an operative that a cure has failed because the cure took place outside of the acceptable limits. This may be communicated to the operative by means of indications on the rack as described above and/or my means of a mobile computing device 17.

Furthermore, predictions can be made as to when and if a predetermined limit is to be reached allowing the operative to intervene and avoid a bad or failed cure.

Referring to figure 7 the master controller or mobile device may receive the cure parameters of the part 2 as determined by the sensor 5. In figure 7 a humidity limit H _max is shown. The humidity may be determined at discrete time intervals and the results extrapolated as shown in figure 7 indicating that if no intervention takes place the humidity limit for the given cure will be reached or breached at time T. The operative can then be warned in advance that it is predicted that a bad cure will take place i.e. a cure that occurs outside of the predetermined limits for the specific cure component.

Figure 8 illustrates a rack comprising different components. Here the master controlled may be configured to indicate to the operative when each component has cured; each one having a different curing time for the determined environmental conditions. The operative can then remove parts that have successfully cured and leave parts that require more time in position.

Advantageously the master controller and communications arrangement (to receive signals from temperature and humidity detectors and to issue control signals to air conditioning or humidity controllers) may be incorporated into the curing apparatus/rack itself providing a mobile arrangement.

As shown in figure 9 the apparatus may be arranged on wheels 18 to allow the cured components to be easily moved. Advantageously the rack may further be provided with an induction power arrangement such that when the rack is positioned over the induction coil 19 power can be supplied to the rack. This may be stored in a battery pack on the rack.

The sensors may also be used to determine if a cure has been interrupted. For example the sensors can indicate to the controller if the part has been removed or repositioned at any time during the cure. This could indicate that a part has been taken out of the desired curing conditions. Each sensor may be provided with its own local controller, with each controller arranged to communicate with a master controller which may be local to the rack or remote therefrom. Each local or slave controller may detect a component and request cure information from the master controller which has access to a cure time/parameter database for all parts.

The local controller may then operate as follows:

1. Has part been detected, YES

2. Send part data to master controller and request cure data

3. Master controller received part cure data and communicates to slave

4. Slave confirms receipt and begins the prescribed cure cycle

5. The slave requests the environmental conditions from the master throughout the cure cycle to ensure the cure parameters remain with the prescribed limits. Throughout the cure cycle, the master controller requests updates on cures from each slave to compile this data for external reporting to a system such as a mobile computing device 17.

An example operation for the system described herein, which might include the above operations of the local controller, is shown in figure 10. In this operation, an operator places at least one part 1 on the rack 8 (step 1001).

The system is then operable to sense the presence of each part 1. For each part 1 , the system then operates using the sensors 5 to determine if the environmental conditions for each part 1 are within the desired curing conditions (step 1002).

On the basis that the environmental conditions are within the desired curing conditions, each part continues to cure. At predetermined intervals, the sensors 5 and the system continue to determine if the environmental conditions for each part 1 are within the desired curing conditions (steps 1003 and 1004), and that each part has not been removed or repositioned (steps 1003 and 1005).

If the environmental conditions deviate from the desired curing conditions during the curing process, the cure process may be signalled as interrupted or aborted, for instance on the display 12 (step 1006). Similarly, if the part 1 is removed or repositioned at any time during the cure, the cure process may be signalled as interrupted or aborted, for instance on the display 12 (step 1007).

On the basis that each part 1 is not removed/repositioned, and remains at the desired curing conditions, for the required curing period, at the end of this curing period the cure process may be signalled as complete, for instance on the display 12 (step 1008).

The rack described herein may also be used in an autoclave application. Advantageously the sensors may be used to determine what components have been positioned on the rack. This information may then be communicated to an autoclave before the rack is positioned inside the autoclave. The autoclave can then ensure that it only applies the correct cure cycle for the parts that have been loaded into it as determined by the sensors and rack arrangement described herein.

It will be recognised that the arrangement described herein may also advantageously be used to record curing data. This may be useful in providing a record that a component in the aerospace industry has been manufactured to agreed standards and conditions and thus provide an audit trail for manufacturers.

It will also be recognised that the arrangements described herein, although being described in the context of a composite part, need not necessarily be limited for use with such a composite part. Indeed, the arrangement may be operable for use with a part of any material and/or composition - e.g. not just composite parts.

In terms of placing each component/part in a predetermined position with respect to the sensor/part-detector, as recited above, in some embodiments this may be achieved using a suitable jig or holding arrangement. In a particular embodiment, the holding arrangement may comprise a plurality of stops, which may in some cases be rubber stops. In some particular embodiments, these stops may comprise different sizes and/or be replaceable - such that an appropriately sized stop can be used to suit a given component. In some embodiments, the holding arrangement and/or the stops may be moveable with respect to the sensor to allow for fine adjustment and positioning of each component with respect to the sensor. In accordance with some embodiments described herein, it has been described that the cure apparatus may comprise a cure rack. In some particular embodiments thereof, the cure rack may comprise a plurality of levels for supporting the plurality of part detectors and the one or more visual display arrangements. With the provision of these levels, this may facilitate easier access to the plurality of part detectors, and easier visibility of the one or more visual display arrangements.

Where the cure apparatus comprises the cure rack, in some particular embodiments thereof, the plurality of levels may comprise a first level and a second level located above the first level; wherein the first level comprises a first portion of the plurality of part detectors and a first portion of the visual display arrangements; and wherein the second level comprises a second portion of the plurality of part detectors and a second portion of the visual display arrangements. In this embodiment, the provision of the first and second levels can allow for a more efficient use of space by the cure rack, and can allow the various cured parts as well as the visual display arrangements to be more effectively separated from each other about the relevant levels of the cure rack.