Method for determining the peel energy by a laying machine and laying machine

Abstract

The invention relates to a method for determining the peel energy by a layup machine and to a layup machine. In particular, the invention relates to the automated manufacturing of composite laminates for structures, preferably for aircraft structures, by using a layup machine. More particularly, the invention relates to a method for determining the peel energy between layers of a composite laminate by a layup machine. The invention also relates to a layup machine for performing the method.

Description

Technical Field

[0001] This invention relates to the automated manufacture of composite laminates for structures, preferably for aircraft structures, using a lay-up machine. More specifically, this invention relates to a method for determining the peel energy between layers of a composite laminate using a lay-up machine. The invention also relates to a lay-up machine for performing said method. Background Technology

[0002] The ability of a material to adhere to itself (e.g., between its layers or to a solid surface) is called adhesiveness or tackiness. This ability is a relevant property for a wide range of industrial applications and materials. Specifically, this ability of a material to adhere to itself or another surface is an extremely important property for the manufacture of fiber-reinforced composite laminates (also known as composite laminates). These composite laminates are manufactured using automated tape laying (ATL) machines or automated fiber placement (AFP) machines.

[0003] This is a key factor in automating the process of depositing the first layer on the laying tool, but it is also a key factor in driving the productivity of the process of depositing the remaining layers of the laminate and defining the final quality of the composite laminate. Depositing this first layer is always complex due to the specific nature of the surface of the tool used for this operation (on which the first layer of the composite laminate is deposited). In most cases, these laying tools are curing tools with very limited features associated with this function.

[0004] When prepreg reinforcements are used in the manufacture of composite laminates, the stickiness or adhesion of the material to itself or the laying tools is mainly related to the properties of the resin impregnating the fiber reinforcement and the level of impregnation of the reinforcement. This stickiness or adhesion is also related to the impregnation characteristics, the specificity of the reinforcement itself, the pressure and heat applied during the deposition process, environmental conditions, and the aging of the material before and after the deposition process.

[0005] On the other hand, when dry fiber reinforcements are used in the manufacture of composite laminates, the tackiness or adhesiveness of the material is mainly related to the properties of the binder (thermosetting or thermoplastic) and / or yarn (thermoplastic) applied to the surface of the reinforcement. This tackiness or adhesiveness is also related to the pressure and heat applied during the deposition process, the specificity of the reinforcement, environmental conditions, etc.

[0006] In both of the above cases, tackiness or adhesion is crucial for applying the first layer of the laminate to the laying tool, and the material of the laying tool, its surface characteristics (surface roughness, surface treatment, presence of additives), and temperature are key factors for proper adhesion of the reinforcement. Furthermore, tackiness or adhesion is equally important when applying the remaining layers of the laminate to other layers; for adhesion between layers in the laminate, the materials of these other layers, their surface characteristics, and their temperatures are also taken into account.

[0007] There are known standard procedures and equipment for quantitatively measuring or qualitatively estimating the tackiness of different materials, particularly for adhesive films and prepregs. For example, there is a standard test method called the rolling ball tackiness test, where tackiness is related to the distance the ball travels along the adhesive surface. Furthermore, there is a ring tackiness test, a determination of the tackiness of adhesives—pressure-sensitive adhesives—where tackiness is related to the energy required to peel the ring from the surface.

[0008] However, the use of these known procedures and devices in industrial environments has the following drawbacks:

[0009] - They are designed for use in laboratory environments.

[0010] - They require the use of sophisticated equipment, procedures, and qualified personnel.

[0011] - Test results are highly dependent on test conditions and personnel involved.

[0012] - Testing requires the extraction of witness samples. Therefore, representativeness relates to the number of samples in each batch and how they are selected. An appropriate balance should be considered between workload and benefits to minimize the impact on production time and costs.

[0013] Due to its complexity, testing is typically conducted only at the material supplier’s site or upon receipt of materials at the customer’s site, and is almost never performed during production. Therefore, aging of the material during its low-temperature storage, aging during its rewarming and room-temperature storage, aging during manufacturing operations, and changes in environmental conditions during manufacturing (e.g., even in a cleanroom, relative humidity varies considerably over a 24-hour period).

[0014] Therefore, the obtained viscosity data is insufficient to represent the actual conditions of the materials used in production.

[0015] Furthermore, the availability of reliable process data, including sticky data, is relevant to processes that allow machines to be kept within the optimal process window, avoiding continuous operator intervention to maintain machines under acceptable conditions based on subjective judgment, which largely depends on the operator and their experience.

[0016] Specifically, the availability of viscous or adhesive data will significantly facilitate the implementation of prepregs and dry fiber reinforcements or advanced manufacturing systems, which, combined with machine learning methods, will enable manufacturing concepts to support high-speed production environments.

[0017] This invention provides a novel method for automatically determining the viscous or adhesive properties of a composite material under real-world conditions using the same laying machine as that used in manufacturing composite laminates. Summary of the Invention

[0018] This invention provides a solution to the above-mentioned problems. This invention proposes a method and laying machine, as defined herein, for determining the peel energy between layers of a laminate.

[0019] In a first aspect, the present invention provides a method for determining the peel energy between a first layer and a second layer of a composite laminate using a layup machine, the layup machine including at least one end effector, the method comprising the steps of:

[0020] a) At least a portion of the second layer is peeled off from the first layer by at least the movement of a component of the end effector of the laying machine that pulls the second layer relative to the first layer.

[0021] b) Measure at least the tensile force applied to the second layer and at least the pulling motion of the end effector components during step a), and

[0022] c) Determine the peel energy between the first layer and the second layer based at least on the measured tensile force and the measured pulling motion.

[0023] This invention provides a method for determining the peel energy of a composite laminate using a layup machine. The determined peel energy represents the tackiness or adhesiveness of the material conforming to the composite laminate. Specifically, this method determines the peel energy between at least two layers (specifically, a first and a second layer). Throughout this document, it should be understood that the laminate, and specifically these first and second layers, may be made of or may include fiber-reinforced composite materials, more particularly made of or including prepreg or dry fiber reinforcement.

[0024] The first and second layers of the composite material conform to the composite laminate, such that when these first and second layers are laminated by a layup machine, an adhesive is provided between them. The laminate may include more than two layers.

[0025] To determine the peel energy between two layers of a composite material, measurements are taken by laying the composite material and performing a peeling routine using the end effector of a layup machine. The end effector is a component of the layup machine responsible for laminating or depositing the material in the form of tapes or tows. That is, the composite material can be deposited as tapes using an automated tape layup (ATL) machine or as tows using an automated fiber layup (AFP) machine. Throughout this document, layers of a composite laminate will be understood as layers of material comprising tapes or tows of fiber-reinforced composite material or multiple tapes or tows of fiber-reinforced composite material.

[0026] Specifically, a force is applied to the composite material under test, and the movement of the end effector components is measured to determine the peel energy between the layers of the composite material. The peel energy of the composite laminate under test conditions is determined using the data obtained from the measurements to understand the viscous or adhesive properties of this particular composite material within the laminate.

[0027] The method includes step a): detaching at least a portion of the second layer from the first layer by pulling the second layer relative to the first layer. To pull the second layer from the first layer, at least the end effector of the laying machine or at least one component of the end effector is moved. That is, by moving at least a component of the end effector, the second layer is pulled relative to the first layer, causing at least a portion of the second layer to detach from the first layer.

[0028] The movement of the end effector or its components can be translation along one or more directions, rotation about one or more axes, or any combination of translation and rotation. One or more components of the end effector, or the entire end effector, can move to pull a second layer. The pull generated on the second layer has at least a non-zero component in a direction orthogonal to the plane of the laminate or to a local tangent of the laminate.

[0029] Once the first and second layers have been at least partially laminated, perform the peeling step a). Specifically, prior to step a), the first layer is laminated onto a laying tool or test plate or another composite layer, and then the second layer is laminated onto the first layer.

[0030] In the method according to the invention, tensile force and pulling motion are measured simultaneously with the peeling step. Specifically, the method includes step b): measuring the tensile force applied to the second layer in step a) and the corresponding pulling motion of at least one moved component of the end effector of the laying machine. These tensile forces and pulling motions cause at least a portion of the second layer to peel off from the first layer. This measurement step b) can be performed simultaneously with the peeling step a).

[0031] In embodiments where the movement of a component of the end effector is a translation of that component, whether in isolation or as a result of translation of the entire end effector, the pulling motion measured in step b) is the displacement of that component. In embodiments where the movement of a component of the end effector is a rotation of that component, the pulling motion measured in step b) is the rotation of that component. In embodiments where the movement of a component of the end effector includes translation and / or rotation of one or more components, step b) may include measuring the displacement and / or rotation of the one or more components.

[0032] Furthermore, the method includes the step of determining the peel energy between the first and second layers. The peel energy is calculated by integrating the tensile force applied to the second layer along the relative displacement during the peeling process. In a particular embodiment where the motion applied in step a) is displacement of a component of the end effector, the peel energy is calculated considering the relative displacement between the end effector component and the first layer. In a particular embodiment where the motion applied in step a) is rotation, this rotation provides displacement of a certain length of composite material, and this displacement is considered when calculating the peel energy as previously described. Specifically, the peel energy is determined at least based on the tensile force and pulling motion measured during the peeling of at least a portion of the second layer from the first layer of the laminate. Furthermore, the peel energy can be normalized by dividing this peel energy by the surface area of ​​the peeled material or by the length of the material peeled for a predetermined width of material strip / tow.

[0033] This invention allows for the automatic determination of the peel energy of composite laminates using the end effector of a laying machine, without modifying the laying machine itself, but only by programming routines to be executed by the numerical controller of such a laying machine. That is, no mechanical modifications to the laying machine are required, thus allowing the use of existing laying machines to perform the method according to the invention. Modifying the program of the laying machine's control unit allows for the acquisition of a machine according to the invention. This operation can be performed automatically by the laying machine or as needed as part of a standard manufacturing process.

[0034] Therefore, advantageously, this method allows for the evaluation of tack or adhesion between composite layers by using the same layup machine to perform the lamination of these composite layers. Their peel energy (representing tack or adhesion) can be determined simultaneously with the lamination of the two composite layers, and this tack result is highly reliable because it takes into account actual layup conditions.

[0035] Compared with the prior art, the present invention proposes a solution in which the stripping energy can be determined by the laying machine itself without the need for testing with the aid of other tools.

[0036] Furthermore, the present invention advantageously allows for the execution of methods for determining the exfoliation energy of materials in a manufacturing environment without the need for execution in a laboratory.

[0037] Since this method is performed by a known laying machine, it is not necessary to use complex equipment or qualified personnel to determine the peel energy of the material, although some modifications have been made as proposed in this invention.

[0038] Therefore, the present invention provides a method for advantageously determining the peel energy of viscous data representing the actual conditions of the materials used in manufacturing.

[0039] In a particular embodiment, the method further includes the following steps prior to step a):

[0040] - Lay the first layer of composite material using the end effector of the laying machine, and

[0041] - The second layer of composite material is laid on top of the first layer using the end effector of the laying machine.

[0042] First, the end effector laminates the first layer of composite material onto a surface (corresponding to the surface of the laying tool, test plate, or another composite layer), and then the end effector also laminates the second layer of composite material onto the first layer. The end effector of the laying machine is configured to cut the first layer once it has been fully deposited, and then begin depositing or laminating the second layer onto the first layer.

[0043] In a particular embodiment, prior to step a), the end effector of the laying machine stops laminating the second layer onto the first layer, and without cutting the second layer, the end effector releases an additional composite material of a predetermined length as a continuation of the already laminated second layer composite material, and the end effector moves to a predetermined position.

[0044] According to this embodiment, once at least a portion of the second layer has been laminated onto the first layer, the end effector of the laying machine stops laminating the second layer and, without cutting this second layer, appropriately releases an additional composite material of a predetermined length in the form of a strip or bundle. This length of released additional composite material corresponds to a continuation of the unlaminated second layer. Thereafter, the end effector of the laying machine shifts to a predetermined position. Due to the shift of the end effector to the predetermined position, the released composite material may be under tension or stretched between the laminated portion of the second layer and the position to which the end effector has moved. However, if this is not the case, the method includes applying tension to the released predetermined length of composite material via a motion routine of the end effector. This motion routine is preferably a translation or displacement, particularly a translation with a non-zero component orthogonal to the plane of the laminate. Applying tension to this released predetermined length of composite material allows the second layer to be at least partially peeled from the first layer, at least by moving (i.e., displacing and / or rotating) a component of the end effector and pulling the second layer relative to the first layer.

[0045] Once the released composite material is stretched or under tension, the end effector of the paving machine, or at least one component thereof, begins to move relative to the first layer. For example, the end effector may move upward or backward, one or more components of the end effector may be displaced or rotated, or a combination thereof. This movement causes the second layer to peel off from the first layer. The tensile force applied to the second layer and the pulling motion performed by the end effector, or at least one component thereof, are measured to determine the peel energy between the first and second layers.

[0046] In a particular embodiment, step a) includes displacing the end effector relative to the first layer, such that the tensioning element of the end effector is thus displaced and the second layer is at least partially peeled off from the first layer, and step b) includes measuring the displacement of the tensioning element relative to the first layer and the tension provided by the tensioning element due to its displacement.

[0047] Known paving machines include a tensioning element configured to maintain a stable paving tension in the end effector and allow for compensation of transient effects. The movement of the tensioning element can be managed by a spring element. In a more specific embodiment, the displacement of the tensioning element is measured by a linear variable differential transformer (LVDT) sensor located in the end effector of the paving machine. Due to the end effector moving upwards or backwards, or a combination of both, the tensioning element of the end effector is displaced, and thus the second layer is at least partially separated from the first layer. In this specific case, the pulling motion of the end effector components measured in step b) corresponds to the displacement of the tensioning element relative to the first layer, and the tension applied to the second layer, also measured in step b), corresponds to the tension provided by this tensioning element due to its movement.

[0048] In a more specific embodiment, step b) includes measuring the torque in the material reel of the end effector caused by the displacement of the end effector.

[0049] The end effector of the layup machine further includes a material reel (e.g., a tape or filament reel) configured to store the composite material to be laminated. In this sense, the layup machine lays the composite material stored in this material reel by movement of the end effector. Specifically, the composite material is wound in the material reel, and thus, for lamination, this composite material is unwound from the material reel to be deposited as a layer.

[0050] In this embodiment, the torque applied by the material reel is also measured as a result of the end effector's movement to determine the peel energy between the composite material layers, representing the adhesiveness or tackiness of the composite material. That is, in step b), the tension applied to the second layer corresponds to the tension provided by the tensioning element due to its movement and the torque applied by the material reel. In this case, both the tension provided by the tensioning element and the torque in the material reel are measured in step b) of this method. In a more specific embodiment, the method can also measure the breaking torque in the material reel.

[0051] In a particular embodiment, step a) includes rewinding the unwound composite material, which is a continuation of the already laminated second layer of composite material, onto a component of the end actuator of the laying machine, such that the second layer is at least partially peeled off from the first layer, and step b) includes measuring the rotation of the component and the torque applied to the same component.

[0052] As an alternative to or in combination with the displacement of the end effector, in this embodiment, the method further includes rewinding the unwound material. Specifically, it is assumed that once a portion of this second layer has been laminated without cutting the composite material of this second layer, the unwound composite material is a continuation of the second layer composite material. Therefore, a portion of the second layer composite material is laminated, another portion is unwound by the end effector, and the remainder is wound around a component of the end effector. This operation of rewinding the unwound composite material causes the second layer to peel at least partially from the first layer. When this occurs, the method measures the rotation of the component to which the material is rewound and the torque applied to the same component to determine the peel energy. In this case, the tension applied to the second layer, measured in step b), corresponds to the torque applied by the component of the end effector divided by the distance between the center of the component and the point where the torque is applied in such a component. Furthermore, to determine the peel energy, the torque divided by the distance between the center of the component and the point where the torque is applied in the component is multiplied by the length of the material rewound by such a component of the end effector.

[0053] Furthermore, the pulling motion measured in step b) corresponds to the rotation of the component of the end effector. Based on this measured rotation, a certain length of displacement of the composite material is determined. Additionally, the method can consider the length of the composite material already wound in the component before rewinding to determine a more precise length. This material length is then used to calculate the peel energy in step c).

[0054] The component on which the composite material can be rewound can be a material reel (disclosed above) or an additive system. The additive system is also included in the end effector of the layer and is configured to supply the composite material to the end effector in preparation for subsequent laying processes. This additive system is also configured to rewind the material on demand or to function as a force gauge. When the additive system is used as a force gauge, it is configured to measure the tension applied to the composite material by measuring the torque generated within the additive system.

[0055] In a more specific embodiment, the component of the end effector on which the composite material is rewound is a material spool, and the rewinding of the composite material by this material spool causes displacement of the tensioning element of the end effector and peeling of at least a portion of the second layer from the first layer, and step b) further includes measuring the displacement of the tensioning element. That is, when the composite material is rewound by the material spool, the tensioning element can thus be displaced and the second layer peels from the first layer. In this particular embodiment, the tension applied to the second layer corresponds to the torque applied by the spool material, and the pulling motion of the end effector component corresponds to the rotation of the spool material and the displacement of the tensioning element, the force, rotation, and displacement being measured in step b) of this method to determine the peeling energy.

[0056] In a particular embodiment, the laminate is laminated onto a test plate including a force measuring device, and step b) includes measuring the tensile force applied to the laminate by the force measuring device as the second layer is at least partially peeled from the first layer. Since the composite material is laminated onto a test plate with a force measuring device, the force applied to the second layer over time is measured by the force measuring device as the second layer is at least partially peeled from the first layer. In this embodiment, the tensile force applied to the second layer to be peeled from the first layer corresponds to the force measured by the force measuring device included in the test plate. In a more specific embodiment, the force measuring device is a force gauge.

[0057] According to the specific embodiment described above, the method further includes a locking addition system to apply tension to the composite material and displace the end effector relative to the first layer, such that the second layer is at least partially peeled off from the first layer. In this embodiment, the pulling motion of a component of the end effector corresponds to the displacement of the end effector itself, and this displacement is also measured in step b).

[0058] In a particular embodiment, during the peeling process in step a), the second layer forms a pull angle relative to the first layer, wherein the pull angle is not equal to 0.

[0059] As described above, a portion of the material is laminated onto the first layer as a second layer, while another portion of the material is released from the end effector and corresponds to the unwound material. This unwound or released material is a continuation of the second layer (not laminated) that forms a pull angle relative to the first layer. This pull angle corresponds to the angle at which the second layer is pulled or displaced relative to the first layer to peel off from it. The pull angle is not zero to ensure that the second layer can separate from the first layer, i.e., there is at least one non-zero orthogonal component of the tension (relative to the surface of the laminate) at the separation point between the second and first layers.

[0060] In a particular embodiment, the method further includes measuring at least one environmental condition and / or at least one process condition.

[0061] Environmental conditions may include the temperature and / or relative humidity of the room in which this method is performed. Some process conditions include the energy applied by the layup machine heater, the layup temperature corresponding to the temperature at the interlocking point where the composite material is pressed against the surface on which it is deposited, the time between layup and peeling of the composite material, and the peeling speed.

[0062] Environmental and / or process conditions are considered together with the determined peel energy, which represents the tackiness or adhesiveness of the composite material conforming to the composite laminate in a more accurate and reliable manner.

[0063] In a particular embodiment, the peel energy is determined in step c) by the processing unit of the layer and based on the measurements performed in step b). In this embodiment, the layer further includes a processing unit configured to process the data measured during the peeling step, as well as optional other parameters (such as environmental and / or process conditions), and to determine the peel energy (representing the tackiness or adhesiveness of the composite material) based on these measurements.

[0064] In an embodiment, the method further includes the step of recording the data measured in step b) and the data determined in step c). In this sense, a database can be generated to store data obtained from testing the tack or adhesion of a particular composite material under specific conditions.

[0065] Therefore, if a database exists of tack or adhesion data obtained by testing the same composite material at different aging levels under the same environmental and process conditions, the test results can be correlated with the database to determine the true condition of the composite material.

[0066] Furthermore, if a database exists of viscous data obtained from testing the same composite material at different aging levels under different environmental and process conditions, and this data is recorded along with environmental and / or process conditions, layup machine parameters, and / or quality data of the composite material structure to be manufactured, these data can be correlated to determine the optimal process for the composite material conditions.

[0067] In a second aspect of the invention, the present invention provides a paving machine configured to perform a method according to a first aspect of the invention, the paving machine comprising:

[0068] - An end effector configured to laminate a composite material, the end effector comprising:

[0069] o Material reel, the material reel being configured to unwind and rewind composite material, or

[0070] a tensioning element, the tensioning element being movable to maintain a stable tension in the composite material, or

[0071] any combination of the above;

[0072] - A processing unit configured to determine the stripping energy according to step c) of the method.

[0073] - A motion sensor, configured to at least measure the pulling motion of a component of the end effector during peeling, and

[0074] - A force sensor configured to at least measure the tensile force applied to the second layer during peeling.

[0075] This layup machine is configured to perform a method for determining the peel energy between composite material layers in a laminate. The layup machine includes motion sensors and force sensors to allow measurement of the pulling motion of components of the end effector and the tensile force applied to the second layer to peel it from the first layer. Based on these measurements, the layup machine is also configured to determine the peel energy of the composite material via a processing unit. The pulling motion can be performed by one or more components of the end effector (e.g., a tensioning element and / or a material reel), by displacement of the entire end effector, or by displacement and / or rotation of any component of the end effector combined with displacement of the end effector itself.

[0076] In a particular embodiment, the layer further includes an addition system for unwinding and rewinding the composite material.

[0077] In a particular embodiment, the laying machine includes a torque sensor configured to measure the torque applied by a component of the end effector. More specifically, the torque is measured on a material reel or adding system.

[0078] In a particular embodiment, the laying machine includes a test plate configured to lay a laminate thereon, the test plate including a force measuring device configured to measure the tensile force applied to the laminate when the second layer is at least partially peeled from the first layer.

[0079] All features described in this specification (including claims, description and drawings) and / or all steps of the described methods can be combined in any combination except for combinations of these mutually exclusive features and / or steps. Attached Figure Description

[0080] Referring to the accompanying drawings and in view of the detailed description of the invention, these and other features and advantages of the invention will become apparent from the preferred embodiments of the invention, which are given by way of example only and are not limited thereto.

[0081] Figure 1This figure shows a schematic diagram of the end effector of a paving machine according to an embodiment of the present invention.

[0082] Figure 2 This figure illustrates an embodiment of the present invention. Figure 1 A schematic diagram of the end effector of a paving machine. Detailed Implementation

[0083] The present invention provides a method for determining the peel energy between a first layer 1 and a second layer 2 of a composite laminate 9 using a layup machine including an end effector 10. Both the first layer 1 and the second layer 2 are supplied by the layup machine and formed by material deposited or laminated by the end effector 10 of the layup machine.

[0084] In order to determine the peeling energy, the second layer 2 is at least partially separated from the first layer 1, and for this purpose, at least one component of the end effector 10 is displaced to apply displacement to the composite material in such a way that the second layer 2 is pulled to separate at least partially from the first layer 1.

[0085] Figures 1 to 2 An end effector 10 of a tape / tow laying machine according to the present invention is shown, specifically, Figure 1 An end effector 10 for deposited composite material (belt / filament) is shown, and Figure 2 An end effector 10 is shown that is configured to begin stripping the second layer 2 from the first layer 1 according to this method.

[0086] according to Figure 1 The laying machine lays the composite material stored in the material reel 3 (belt / filament reel) through the movement of the end effector 10. The deposition of this composite material takes place on the surface of the laying tool 11 and produces a composite material laminate 9.

[0087] The pressure roller 7 presses the material strip / tow against the already deposited first layer 1 at the engagement point 8, thereby allowing the composite material to adhere between layers 1 and 2. While the pressure roller 7 presses the composite material, the heating element 13 provides heat at the engagement point 8 to facilitate the deposition of this composite material. The end effector 10 may include an energy sensor for measuring the energy applied through the heating element 13 and / or a temperature sensor for measuring the temperature at the engagement point 8.

[0088] The end effector 10, parallel to the programmed movement of the laying tool 11, lays the composite material unwound from the material reel 3 along with the pressure applied by the pressure roller 7. Simultaneously, a protective polyethylene carrier is rewound into the polyethylene spool 5, only when the material to be deposited is prepreg rather than dry fiber. Breakage in the material reel 3 controls over-unwinding of the composite material. Depending on process requirements, a motor connected to the material reel 3 can also be used to add or rewind the composite material. The end effector 10 includes a torque sensor that measures the torque of breakage in the material reel 3 or the torque of the motor.

[0089] The end effector 10 further includes a tensioning element 4 for maintaining a stable layup tension for the composite material through its movement. The movement of the tensioning element 4 is controlled by a spring element 14 that allows compensation for transient effects. The end effector 10 includes a displacement sensor configured to measure the displacement of the tensioning element 4. In a particular example, this displacement sensor is an LVDT sensor.

[0090] According to the laying process, the composite material to be deposited is extracted from the material reel 3 and trimmed to the programmed length by the blade of the cutter 12. The end effector 10 continues its movement parallel to the laying tool 11 until the end of the programmed position, and ends the deposition of the composite material layer.

[0091] The end effector 10 further includes an addition system 6, which disengages during the laying step and is activated to supply material to the end effector 10 in preparation for subsequent laying processes. This addition system 6 can also be used to rewind the composite material as needed or as a force gauge to measure the tension applied to the composite material by measuring the combined torque in the addition system 6. The torque in the addition system 6 is measured by a torque sensor.

[0092] The aforementioned end effector 10, according to the invention, is configured to execute a programmed motion routine for at least partially peeling one layer of a composite laminate from another, so as to automatically measure at least the pulling motion in the end effector 10 and the tensile force applied to the layers during layer peeling. Based on these measurements, the method determines the peel energy between the composite layers. This peeling operation is performed by the actual production apparatus (laying machine) and can be performed automatically or on demand as part of the manufacturing process.

[0093] according to Figure 2 The end effector 10 shown is... Figure 1 This is the same as the end effector described above. Specifically, in Figure 2 In this embodiment, the cutter 12 and heating element 13 are not shown because they are not involved in the peeling operation. However, in this embodiment, the method takes into account the temperature conditions at the engagement point 8 as measured by a temperature sensor (e.g., ...). Figure 1(as shown) and / or the energy in the heating element 13 measured by the energy sensor (e.g. Figure 1 (As shown), and the determined peel energy representing the adhesion between the first layer 1 and the second layer 2 of the composite laminate 9. That is, Figure 2 The end effector 10 shown is only a component that can be actuated in this method to at least partially peel the second layer 2 from the first layer 1.

[0094] The above reference Figure 1 and Figure 2 The composite material mentioned is a fiber-reinforced composite material that can be in the form of ribbons, tows, or multiple ribbons or tows. That is, the layers of the composite laminate 9 are composed of simple ribbons or tows or multiple ribbons or tows. In this document, the terms "material" or "composite material" are used interchangeably to refer to ribbons or tows or multiple ribbons or tows.

[0095] Specific examples of the method according to the present invention are described below. This method can be implemented by including, for example... Figures 1 to 2 The layup machine of the end effector 10 shown determines the peel energy between the first layer 1 and the second layer 2 of the composite laminate 9.

[0096] The method includes the following steps: depositing at least a first layer 1 and a second layer 2.

[0097] - The first layer 1 of the composite material is laid by the end effector 10 of the laying machine, and

[0098] - The second layer 2 of the composite material is laid on the first layer 1 by the end effector 10 of the laying machine.

[0099] The first layer 1 can be deposited on another composite material layer that also forms part of the laminate 9, or it can be deposited on the laying tool 11. Specifically, once the first layer 1 has been deposited, the deposition of the second layer 2 is as follows: Figure 1 As shown.

[0100] When the second layer 2 is at least partially deposited, the end effector 10 stops laminating the second layer 2 onto the first layer 1, and without cutting this second layer 2, the tape reel 3 of the end effector 10 releases an additional material tape of a predetermined length. The end effector 10 then moves to a predetermined position such that the released composite material tape is tensioned between the already laminated second layer 2 and the tape reel 3, as... Figure 2 As shown. In a particular example, if the predetermined length of the belt released once the end effector 10 is moved to a predetermined position is not under stress, the method further includes applying tension to the predetermined length of the belt being released by displacing the end effector 10 relative to the first layer 1 before step a).

[0101] Specifically, Figure 2The end effector 10 and its in Figure 1 The position in the middle (where it performs the deposition of the second layer 2 on the first layer 1) is shifted compared to the position from the laminate 9. For example... Figure 2 As shown, shifting the end effector 10 to a predetermined position allows the roller 7 to reach a location where it cannot apply pressure to the laminate 9.

[0102] Once the end effector 10 is positioned in the predetermined location, the method performs step a): at least a portion of the second layer 2 is peeled from the first layer 1 by at least the movement of a component of the end effector 10 of the paving machine that pulls the second layer 2 relative to the first layer 1. Simultaneously with step a), the method performs step b): measuring at least the tension applied to the second layer 2 and at least the pulling movement of a component of the end effector 10 during step a).

[0103] According to step a), the method performs a displacement of the end effector 10 relative to the first layer 1, such that the tensioning element 4 of the end effector 10 is thus displaced and the second layer 2 is at least partially peeled off from the first layer 1. According to step b), the displacement of the tensioning element 4 relative to the first layer 1 is measured, and the tension provided by the tensioning element 4 due to its displacement is also measured in step b). In this case, the tension applied to the second layer 2 corresponds to the tension provided by the tensioning element 4, and the pulling motion measured in this method corresponds to the displacement of the tensioning element 4.

[0104] Furthermore, the method can further measure the torque and / or rotation in the belt reel 3 caused by the movement of the end effector 10 in step b). In this case, the tension applied to the second layer 2 corresponds to the torque applied to the belt material 3, and the pulling motion corresponds to the displacement of the end effector 10, the displacement of the tensioning element 4, and the rotation of the belt material 3.

[0105] In addition to or as an alternative to the disclosed step a), in this embodiment, the method performs a rewinding phase. Specifically, the unwound tape, which forms part of the second layer as a continuation of the second layer 2, is rewound onto the tape reel 3 or the addition system 6. Through this tape rewinding, the second layer 2 is at least partially peeled off from the first layer 1. In step b), the rotation of the tape reel 3 or the addition system 6 and the torque thereby applied are measured. Specifically, the tension applied to the second layer 2 corresponds to the torque applied to the tape reel 3 and / or the addition system 6 divided by the distance between the center of the tape reel 3 and / or the addition system 6 and the engagement point where the torque is applied in the tape reel 3 and / or the addition system 6. Further, the pulling motion corresponds to the rotation of the tape reel 3 and / or the addition system 6. In addition, based on the measured rotation, a certain length of material displacement is determined, and then the peeling energy is calculated in step c). Furthermore, the length of the tape stored in the tape reel 3 or the addition system 6 before rewinding the unwound tape can be measured in this method to more accurately determine the length of the rewound material. To determine the peel energy in step c), the torque is divided by the distance between the center of the tape reel 3 and / or the addition system 6 and the point where the torque is applied in the tape reel 3 and / or the addition system 6, multiplied by the length of the material rewound by the tape reel 3 and / or the addition system 6.

[0106] Furthermore, in step a), the rewinding of the material roll 3 causes the tensioning element 4 to shift; therefore, in step b), the shift of the tensioning element 4 is further measured. That is, the pulling motion in this embodiment corresponds to both the rotation of the material roll 3 and the shift of the tensioning element 4. Based on the rotation of the material roll 3, a certain length of material shift is determined, and then, together with the shift of the tensioning element 4, the peeling energy is calculated in step c) of this method.

[0107] In order to pull the material strip from the adding system 6 or the belt reel 3, the roller 7 must be in the upward position. Figure 2 With the end effector 10 performing the deposition of material Figure 1 (in comparison), so that the second layer 2 can be separated from the first layer 1.

[0108] Before the second layer 2 begins to peel from the first layer 1 and once the end effector 10 or any of its components has been displaced as needed, the undeposited strip of material in the second layer 2 forms a pull angle (α) relative to the first layer 1. That is, at the moment the second layer 2 is about to separate from the first layer 1, this second layer 2 forms a pull angle (α) relative to the first layer 1. This pull angle (α) corresponds to the angle at which this second layer 2 forms relative to the first layer 1 when the second layer 2 is pulled away from the first layer 1. According to a particular example, the pull angle (α) changes as the second layer 2 peels from the first layer 1. This pull angle (α) is not equal to 0, and preferably, 0 < α ≤ 180°.

[0109] exist Figures 1 to 2 In another example, not shown, the laminate 9 is deposited on a test plate instead of a tool plate. This test plate includes a force measuring device (preferably a force gauge) configured to measure the force applied to the laminate 9 as the second layer 2 is at least partially peeled from the first layer 1. The test plate can be adapted to increase adhesion between the laminate 9 and the test plate. The force measured by the force gauge corresponds to the tensile force applied to the second layer 2.

[0110] Any of the aforementioned forces (torque, rotation, ...) or combinations thereof measured in step b) provide the tension applied to the second layer 2 during step a). For example, the tension is provided by the displacement of the tensioning element 4 caused by the actuation of the spring element 14. In addition, any of the aforementioned displacements or combinations thereof measured in step b) also provide the tensile displacement of the second layer 2.

[0111] In addition to the possible data to be measured as described above, in this embodiment, the method further includes measuring environmental conditions (such as temperature and relative humidity) in the manufacturing chamber in step b), and / or process conditions, such as the energy applied by the layer heater, the layup temperature (temperature at the interlocking point 8), the time between the laying and peeling of the material strip, and the peeling speed.

[0112] All of the data obtained in step b) are used in a subsequent step c) of this method to determine the peel energy between the first layer 1 and the second layer 2 of the composite laminate 9. Specifically, the tape layup machine further includes a processing unit configured to determine the peel energy based on data related to pulling motion and tension measured in step b).

Claims

1. - A method for determining a peel energy by a layup machine, the peel energy being a peel energy between a first ply (1) and a second ply (2) of a laminate (9) of a composite material, the layup machine comprising at least one end effector (10), the method comprising the steps of: a) peeling at least a portion of the second ply (2) from the first ply (1) by at least a movement of a component of the end effector (10) of the layup machine pulling the second ply (2) relative to the first ply (1), b) measuring at least a pulling force exerted on the second ply (2) and at least a pulling movement of the component of the end effector (10) during step a), and c) determining the peel energy between the first ply (1) and the second ply (2) based at least on the measured pulling force and the measured pulling movement.

2. - The method according to claim 1, wherein, Before step a), the end effector (10) of the layup machine stops laminating the second ply (2) on the first ply (1) and, without cutting the second ply (2), the end effector (10) releases a predetermined length of additional composite material as a continuation of the second ply (2) composite material already laminated and the end effector (10) is displaced to a predetermined position. 3.- The method according to claim 2, further comprising applying a tension to the released predetermined length of composite material.

4. - The method according to any one of the preceding claims, wherein, Step a) comprises displacing the end effector (10) relative to the first ply (1) so that a tensioning element (4) of the end effector (10) is thus displaced and the second ply (2) is at least partially peeled from the first ply (1), and wherein step b) comprises measuring the displacement of the tensioning element (4) relative to the first ply (1) and a pulling force provided by the tensioning element (4) due to its displacement.

5. - The method according to claim 4, wherein, Step b) further comprises measuring a torque in a material reel (3) of the end effector (10) due to the displacement of the end effector (10). 6.- The method according to any one of the preceding claims, wherein, Step a) comprises rewinding the composite material already unwound as a continuation of the second ply (2) composite material already laminated on a component (3, 6) of the end effector (10) of the layup machine so that the second ply (2) is at least partially peeled from the first ply (1), and wherein step b) comprises measuring a rotation of the component (3, 6) and a torque exerted on the same component (3, 6).

7. - The method according to claim 6, wherein, The component of the end effector (10) is a material reel (3) and said rewinding of the composite material by this material reel (3) causes a displacement of a tensioning element (4) of the end effector (10) and a peeling of at least a portion of the second ply (2) from the first ply (1), and wherein step b) further comprises measuring the displacement of the tensioning element (4). 8.- The method according to any one of the preceding claims, wherein, The laminate (9) is laminated on a test plate comprising a force measuring device, and wherein step b) comprises measuring a pulling force exerted on the laminate (9) by the force measuring device when the second ply (2) is at least partially peeled from the first ply (1). 9.- The method according to any of the preceding claims, further comprising before step a): - laying a first layer (1) of composite material by an end effector (10) of the layup machine, and - laying a second layer (2) of composite material on the first layer (1) by the end effector (10) of the layup machine. 10.- The method according to any one of the preceding claims, wherein, During the peeling off of step a), the second layer (2) forms a pull angle (a) with respect to the first layer (1), and wherein the pull angle (a) is not equal to 0. 11.- The method according to any of the preceding claims, further comprising measuring at least one environmental condition and / or at least one process condition. 12.- The method according to any one of the preceding claims, wherein, The peeling off can be determined in step c) by a processing unit of the layup machine and based on the measurements performed in step b). 13.- A layup machine configured to perform the method according to any of claims 1 to 12, the layup machine comprising: - an end effector (10) configured to laminate composite material, the end effector (10) comprising: o a material spool (3) configured to unwind and rewind composite material, or o a tensioning element (4) movable to maintain a steady tension of the composite material, or o any combination of the above; - a processing unit configured to determine the peeling off energy according to step c) of the method, - a motion sensor configured to measure at least a pulling motion of a component of the end effector (10) during peeling off, and - a force sensor configured to measure at least the pulling force applied to a second layer (2) during peeling off. 14.- The layup machine according to claim 13, further comprising a torque sensor configured to measure a torque applied by a component (3, 6) of the end effector (10). 15.- The layup machine according to any of claims 13 to 14, further comprising a test plate (7) configured to lay a laminate (9) thereon, the test plate comprising a force measuring device configured to measure a pulling force applied on the laminate (9) when the second layer (2) is at least partially peeled off from the first layer (1).

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