Thermoplastic matrix composite material blank stamping equipment

Abstract

The invention relates to a thermoplastic matrix composite blank stamping apparatus, in particular those reinforced with continuous fibers such as carbon or glass. When a complex geometrical shape is formed through a traditional stamping technology, wrinkles, layer corrugations and other defects often occur, the mechanical integrity is reduced, and parts are not suitable for high-performance application such as aviation. To address these issues, the disclosed apparatus incorporates a stamping device having a movable punch (800) and a stamping die (500), a transfer frame (400) supporting a composite stamped blank (200), and a tensioning mechanism that maintains a controlled force on the blank during stamping. The transfer frame includes at least two retaining members (300) that clamp the composite blank along an edge (220) of the composite blank, ensuring precise positioning and controlled tensioning. These retaining members (300) cooperate with receiving members (550) attached to the stamping die in the retaining assembly, securely clamp the blank edges, and allow guided translational and pivotal movement, creating tension in the blank, preventing wrinkles from occurring.

Description

[0001] Related applications

[0002] This application claims priority from French application #FR2402638 filed on March 15, 2024. Technical Field

[0003] The present invention belongs to the field of the implementation of composite materials having a thermoplastic polymer matrix.

[0004] More particularly, the invention belongs to the field of stamping and forming, in which a blank in the form of a composite sheet reinforced with fibers is formed by deformation between a punch and a pair of matrices. Background Art

[0005] Stamping is a technique for forming thermoplastic matrix composite materials that enables non-developable three-dimensional shapes to be obtained from a substantially flat stamped blank.

[0006] More specifically, when a composite stamping blank is reinforced with continuous fibers to form a laminate, particularly fibers made of a non-plastic material such as carbon or glass fibers, deformation of the stamping blank to conform to the shape of the punch and die during the stamping process is achieved by interlaminar sliding between the laminates.

[0007] To this end, the solidified or semi-solidified but rigid stamping blank is heated to a temperature approximately at or slightly above the melting point of the thermoplastic polymer matrix prior to stamping, thereby achieving this deformation mechanism.

[0008] The stamped blank is then in a desolidified state, in which the blank is punched and resolidifies between the punch and the die at the end of the punching process.

[0009] Before stamping and during the heating phase, the stamped blank is carried by a transfer frame as described in documents EP 3 065 931 B1 and EP 4 349 560 B1, which also allows precise positioning of the blank relative to the stamping die.

[0010] These prior art techniques are satisfactory. However, when the final component (100) comprises Figure 1 When the curved portion (110) is shown, the formation of the portion involves shrinkage of some areas, and therefore, such shrinkage is prone to wrinkling, which may cause ripples in the fiber layers in the final part, or even cause the polymer matrix between the fiber layers to twist.

[0011] The wrinkling phenomenon in the shrinking part during stamping is basically a geometric phenomenon, but in the case of composite stamping blanks reinforced with continuous fibers that do not have plasticity, this phenomenon tends to spread to the entire part, including the non-shrinking area.

[0012] In addition to potential shape deviations, defects such as layer corrugations or twisting of the polymer matrix between layers can significantly reduce the mechanical properties of the component, making it unsuitable for demanding applications such as aerospace and thus eliminating its use in such applications. For this reason, it is simply not feasible to mass-produce such components using existing stamping technology. Summary of the Invention

[0013] In order to address the shortcomings of the prior art, the present disclosure provides support for a device, the device comprising:

[0014] a stamping device comprising a stamping die and a movable punch capable of vertically moving relative to the stamping die between an open position and a closed position, the closed position defining a gap between a wall of the stamping die and a wall of the movable punch;

[0015] a composite stamping blank comprising reinforcing fibers in a thermoplastic polymer matrix;

[0016] a transfer frame configured to support the composite stamping blank along at least two edges of the composite stamping blank and including an open area around a periphery of the stamping die;

[0017] rails for moving the transfer frame over the stamping die and between an upper position and a lower position relative to the stamping die,

[0018] wherein the transfer frame comprises at least two holding members, each of the holding members being configured to hold a holding portion of the composite stamping blank on each of the at least two edges;

[0019] each of the protective members including a bore configured to cooperate with a centering pin of a receiving member attached to the impact die;

[0020] The stamping die comprises at least two receiving members, the receiving members being configured to cooperate with the at least two holding members so as to connect each of the holding members to each of the receiving members via the centering pin when the transfer frame is transferred from the upper position to the lower position;

[0021] Each of the receiving members is attached to the stamping die by a pivotal coupling about a horizontal axis; and

[0022] Each of the receiving members includes at least one slide groove, so that when the at least two retaining members are connected to the at least two receiving members, the at least two retaining members are guided to translate relative to the at least two receiving members within a sliding plane parallel to the horizontal axis and in a direction perpendicular to the horizontal axis.

[0023] Thus, the retaining members are connected to the receiving members, which retaining members exert a tensile force on the composite stamped blank during the stamping operation, while accompanying the rotation of the retaining part during the forming process, thereby avoiding the occurrence of wrinkles.

[0024] The device can be implemented according to the embodiments disclosed below and their variants, which can be considered individually or in any technically feasible combination.

[0025] According to some embodiments, the at least two retaining members are clamps.

[0026] In some embodiments, the at least two retaining members may include claws configured to be inserted into retaining holes drilled on the at least two edges of the composite stamped blank.

[0027] In some embodiments, the at least two retaining members may include a cover covering the area where the claws are located.

[0028] Therefore, during the heating of the composite stamping blank, the portion of the composite stamping blank placed in the fixture does not separate, thereby ensuring that the portion is firmly gripped during the heating and stamping operations.

[0029] In some embodiments, the pivot coupling may include a first indexing mechanism configured to index the pivot coupling at a position about the horizontal axis to receive the at least two retaining members when the transfer frame moves from the upper position to the lower position.

[0030] According to some embodiments, the first indexing mechanism may include an adjustable setting of a de-indexing torque about the horizontal axis.

[0031] According to some embodiments, the at least two receiving members may include a spring configured to resist a force of displacement of the at least two retaining members as they translate relative to the at least two receiving members.

[0032] In some embodiments, the apparatus may include a ball bearing mounted on the centering pin, the ball bearing being configured to cooperate with the upper slide groove to guide each of the retaining members to translate relative to each of the receiving members.

[0033] Such an arrangement makes it possible to absorb the transverse forces caused by the tensioning of the composite stamped blank, thereby ensuring that, when subjected to these transverse forces, the retaining element does not jam during translation relative to the receiving element.

[0034] In some embodiments, the apparatus may include a tether and a tensioner configured to control a tilting torque of the at least two receiving members about the horizontal axis during a stamping process.

[0035] The variable tensioner may further include a computer including a non-volatile memory including a control program for controlling the tensioner and the tipping torque based on parameters measured during the punching process, the parameters being selected from the displacement of the movable punch and the force applied to the movable punch, or a combination thereof.

[0036] According to some embodiments, the reinforcing fibers may be selected from continuous fibers, long fibers, and short fibers. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The device may be in accordance with the non-limiting embodiments and variations thereof disclosed below and with reference to Figures 1 to 9 To implement, where:

[0038] Figure 1 An embodiment of a component produced by implementing the apparatus is shown according to a perspective view and a schematic cross-sectional view of a stamping operation;

[0039] Figure 2 The top view shows the method for manufacturing Figure 1 An exemplary embodiment of a composite stamped blank of a component is shown;

[0040] Figure 3 is a partial perspective view and exploded view of an exemplary embodiment of a retaining member;

[0041] Figure 4 An exemplary embodiment of a transfer frame is shown according to a top view, which is configured to support Figure 2 The composite stamping blank shown in FIG. Figure 3 The retaining member shown;

[0042] Figure 5 yes Figure 4 A cross-sectional view of section AA defined in FIG, showing an exemplary embodiment of an assembly including a retaining member and a receiving member;

[0043] Figure 6 yes Figure 9 A partial cross-sectional view of section BB defined in FIG, showing an exemplary embodiment of a retaining assembly including a retaining member and a receiving member;

[0044] Figure 7 Another embodiment of the holding assembly is shown in a partial view of section BB;

[0045] Figure 8A further embodiment of a holding arrangement is shown in a partial view in section BB, which includes a device for adjusting the tilting torque of the guiding upper part.

[0046] Figure 9 1 is a top view showing a stamping die including a plurality of holding components and a composite stamping blank after stamping, as well as the force exerted by the holding components on the composite stamping blank during the stamping process.

[0047] To facilitate reading, not all components are shown from one figure to another. DETAILED DESCRIPTION

[0048] like Figure 1 As shown, the principle of stamping is to form an initially substantially flat blank between a stamping die 500 comprising an impression 810 and a pair of movable punches 800, which are movable between an open position and a closed position, wherein, in the closed position, the outer shape of the movable punch is separated from the shape of the impression by a gap 190 corresponding to the thickness of the finished part.

[0049] This forming is achieved by relative movement 150 of the movable punch 800 towards the stamping die 500 .

[0050] Throughout this article, the concepts of vertical or horizontal are relative and relate to the relative punching movement of the movable punch with respect to the punching die, which is considered to be vertical. In fact, when the tool is mounted on the press, in most cases this movement is carried out in the vertical direction.

[0051] Those skilled in the art will appreciate that the relative movement of the movable punch relative to the stamping die can be performed in other directions, particularly horizontally, on other machine implementations without modifying the operation of the equipment. Thus, the vertical direction is typically the direction of movement of the movable punch applied by the press during the stamping process.

[0052] like Figure 2 As shown, according to some embodiments, Figure 1 The illustrated component is obtained by stamping a substantially planar composite stamping blank 200 of laminated composite material including a layer of continuous fibers 210, i.e., fibers extending from one edge of the composite blank to the other, and a thermoplastic polymer matrix.

[0053] According to some embodiments, the composite stamping blank 200 is cut from a fully consolidated plate by an abrasive water jet or a cutting tool, or can be obtained by the method described in document EP2819823, or can be partially consolidated and obtained by draping prepreg layers or by the automatic fiber placement method described in documents EP3096940 and US2018 / 0319102.

[0054] According to a non-limiting embodiment, more particularly for aerospace applications, the thermoplastic polymer from which the matrix is ​​made may be selected from PEI, PPS, PEEK, PEK, PEKK or in:

[0055] PEI: polyetherimide,

[0056] PPS: polyphenylene sulfide,

[0057] PEEK: Polyetheretherketone,

[0058] PEK: polyetherketone,

[0059] PEKK: polyetherketoneketone, and

[0060] "Low melting point polyaryletherketone" is a trade name for a low melting point polyaryletherketone supplied by VICTREX PLC Ctrex Technology Centre Hillhouse International, Thornton FY5

[0061] 4QD, United Kingdom).

[0062] According to non-limiting examples, the fiber layer may include carbon fibers, glass fibers, or aramid fibers in the form of a woven fabric, a nonwoven fabric, a nonwoven unidirectional web, or deposited by automated fiber placement.

[0063] Regardless of the embodiment, the composite stamping blank is rigid at room temperature and should be brought to a temperature close to, and usually slightly above, the melting point of the thermoplastic polymer matrix in order to be capable of being formed by stamping.

[0064] This heating can be achieved by placing the composite stamping blank on a transfer frame that moves under the infrared radiation plate. The transfer frame can also allow heating on both sides of the composite stamping blank.

[0065] The composite stamping blank may further include a plurality of maintaining holes 220 with a diameter of 2 mm to 5 mm, depending on the thickness of the blank. These maintaining holes may be drilled holes and distributed on at least two opposite edges of the blank.

[0066] The edge distance of the drilled hole can be set to a distance l from the edge of the composite stamping blank, where l is at least equal to the thickness of the blank.

[0067] like Figure 3 As shown, the drilled holes at at least two opposing edges of the composite stamped blank may be configured to cooperate with the retaining member 300 .

[0068] Each holding member includes a holding base 310, which, according to some embodiments, may include claws 320 configured to be inserted into the retaining holes 220 when the blank is placed on the transfer frame. However, for some applications, the holding member may also be a clawless clamp.

[0069] A cover 330 may be assembled to the retaining base, covering a portion of the rim adjacent the retaining aperture.

[0070] In some embodiments, the retaining member 300 can rest on two arms 340 that extend on either side of the retaining base 310. The retaining base includes a hanger rod 350 that is configured to be inserted into an open recess 345 located at the end of each of the two arms 340.

[0071] like Figure 4 As shown, two arms 340 are connected to the transfer frame 400 on opposite ends of the open recess 345 .

[0072] The position and orientation of the two arms 340 relative to the transfer frame 400 are adjustable.

[0073] like Figure 3 As shown, the retaining base 310, the cover 330, the claw 320 and the two arms 340 can be made of steel, such as a steel with a low coefficient of thermal expansion, such as that known as Nickel-iron alloy steel is used to minimize the expansion stress when the composite stamping blank is heated.

[0074] In addition to holding the composite stamped blank in place, the cover 330 also provides thermal retention, limiting the temperature rise in the portion of the blank edge area located below the cover so that this area can maintain the position of the composite stamped blank and withstand the tension of the blank during stamping.

[0075] In order to achieve interlayer sliding during the stamping process, the composite stamping blank can be heated to a temperature of Tf+30°C to Tf+50°C, where Tf is the melting point of the thermoplastic polymer matrix. The edge portions of the composite stamping blank are held in the retaining member at a distance l between the claws 320 and the edge of the blank, protected by the cover, and these portions can be at a slightly lower temperature in the temperature range of Tf-20°C to Tf-5°C, so that these portions remain unchanged during the stamping process.

[0076] like Figure 4 As shown, the composite stamping blank 200 is set on the transfer frame 400 and fixed thereto by at least two holding members 300, the two arms 340 of each holding member clamping the holding part of the blank, at least two supporting parts are clamped by at least two holding members, and at least two holding members are located at opposite edges of the composite stamping blank.

[0077] The transfer frame 400 may be conveyed by rails 450 under a radiant plate (not shown) for a time sufficient to heat the blank to a sufficiently high temperature within a sufficiently long holding time to desolidify the thermoplastic polymer matrix outside the portion held by the holding member.

[0078] The transfer frame 400 carrying the desolidified composite stamped blank may then be placed between the stamping matrix and the movable punch, in an upper position of the frame, above the stamping matrix.

[0079] The transfer frame 400 includes Figure 4 The open area 411 shown by the hatching in FIG, which surrounds the periphery 410 of the stamping die. Thus, starting from the upper position, the transfer frame 400 carrying the desolidified composite stamping blank can be lowered toward the stamping die to the lower position.

[0080] like Figure 3 As shown, at least two holding members 300 may include a centering and positioning arrangement configured to cooperate with a holding and positioning device carried by the stamping die. According to some embodiments, on the holding member side, this arrangement includes a cover 330 and a bore 390 passing through the holding base 310 outside the composite stamping blank clamping area.

[0081] According to a variant, the bore 390 may be cylindrical or conical.

[0082] like Figure 5 As shown, when the transfer frame is in the lower position, the suspension pin 350 of each holding member 300 is released from the two arms 340. The stamping die 500 may include at least two receiving members 550 attached to the stamping die, each receiving member facing each holding member.

[0083] Each receiving member 550 may include a substantially vertical centering pin 590 configured to fit into the bore 390 such that the centering pin 590 is inserted into the bore 390 when the transfer frame moves from the upper position to the lower position.

[0084] The assembly including the retaining member connected to the receiving member 550 by the centering pin 590 is designated as retaining assembly 501 .

[0085] The retaining member can pivot about the centering pin 590. According to a particular embodiment, as Figure 5 As shown, for one or more retaining members 300 , the bore 390 may be a rectangular bore that enables limited lateral displacement of the retaining member 300 relative to the centering pin 590 in addition to pivoting during the stamping process.

[0086] In some embodiments, the receiving member 550 includes a receiving base 510 attached to the stamping die 500 and a guiding upper portion 520, which is connected to the receiving base 510 by a pivot connection member around a horizontal axis 521 and substantially parallel to a portion of the edge of the composite stamping blank, which is retained in a retaining member 300 connected to the same receiving member.

[0087] The guiding upper portion 520 may include at least one guide slot for guiding the centering pin 590 in a direction substantially perpendicular to the horizontal axis 521 of the pivot coupling.

[0088] According to some embodiments, the centering pin 590 can be guided by a ball bearing 530 in an upper slide groove 522 including a straight groove, and the function of the ball bearing is basically to withstand lateral forces during the stamping process. The centering pin can also be guided in a lower slide groove 523, and the lower slide groove may include a dovetail groove, which cooperates with a tapered wedge block 540 connected to one end of the centering pin, and the lower slide groove provides guidance parallel to the upper slide groove.

[0089] According to other embodiments, Figure 7 As shown, the wedge 740 does not guide the centering pin, but only provides positioning of the centering pin 590 and its alignment with the bore 390 before punching by the second indexing mechanism 741. The screw 742 can be used to adjust the initial position of the wedge 740 and the centering pin 590.

[0090] like Figure 6 As shown, according to some embodiments, the receiving member can include a first indexing mechanism 630 that maintains the guide upper portion 520 in a configuration where the centering pin 590 is vertical. The guide upper portion 520 is adjustable in torque to be deflected from the receiving base 510 by pivoting about the horizontal axis 521 of the pivot coupling.

[0091] like Figure 7 As shown, the second indexing mechanism 741 can be calibrated to translate the release centering pin at a given force.

[0092] Thus, during movement of the transfer frame from the upper position to the lower position, the centering pins 590 of the receiving member are inserted into corresponding bores of the retaining member 300 before the punching operation and the retaining member is substantially horizontal when it is placed on the receiving member.

[0093] To perform the stamping operation, the movable punch is moved according to a vertical direction towards the stamping die 500 and in the process exerts forming pressure on the composite stamped blank, pushing it against the stamping wall.

[0094] Under the effect of this forming action exerted on the composite stamped blank, the guiding upper portion 520 of the receiving member deflects and moves according to a tilting movement 691 about its pivotal connection as the blank is formed.

[0095] Similarly, in Figure 7 In the illustrated embodiment, the centering pin 590 is offset from the wedge 740 , allowing the retaining member 300 to slide relative to the guide upper portion 520 .

[0096] The retained portion of the composite stamped blank 200 held in the retaining member 300 maintains a secure hold.

[0097] As punching proceeds, the centering pin 590 and the retaining member 300 move according to a sliding movement 692 relative to the guide upper part 520 , which is guided in translation by the ball bearing and the tapered wedge 540 in its respective slideway.

[0098] According to some embodiments, the retaining assembly may include an adjustment mechanism 640 to resist the sliding force, such as by a spring 641 to resist the sliding force.

[0099] like Figure 8 As shown, according to some embodiments compatible with the preceding ones, the device may comprise means for controlling the tilting torque of the guiding upper part 520 .

[0100] According to some embodiments, these control means may include a tensioner 840 configured to apply tension on a tether 841 , such as a cable or chain, connected to the guiding upper portion 520 of the retaining assembly via a pulley 842 .

[0101] The tensioner can be a calibrated spring or, according to some other embodiments, an actuator controlled by a computer 890, such as an electric cylinder or a chain cylinder, to apply a defined tension in the tether 841. This tension can be measured by a force sensor 891 and controlled by a program that is based on information 892 related to the vertical position of the movable punch or the force applied to the movable punch 800, or a combination thereof.

[0102] Such a control device may act on all or some of the holding assemblies according to the same control configuration or according to a force control configuration applicable to each holding assembly.

[0103] These control configurations may be determined through simulation and / or testing prior to implementation in series production of the stamping equipment.

[0104] Furthermore, these control means also make it possible to avoid any collision between the movable punch 800 and the holding member 300 during the punching process.

[0105] like Figure 9 As shown, the distance between the retaining members 300 attached to their respective receiving members 550 is substantially constant during the stamping process.

[0106] According to some variations, the bore 390 is cylindrical and only allows angular displacement of the retaining member 300 about the centering pin 590 so that the retaining member matches the tension generated in the composite stamped blank 200 during the stamping process.

[0107] According to some other variations, the bore of at least one retaining member 300 is a rectangular bore 391 , thereby allowing, in addition to angular alignment, limited lateral displacement of the retaining member comprising such an arrangement in translation.

[0108] Regardless of the variant, these retaining components accompany the composite stamping blank 200 during its forming process, thereby avoiding any tearing or jamming, while applying some tension to the blank during the stamping process, which is caused by Figure 9 The arrows in the figure indicate that wrinkles should be avoided.

[0109] During the stamping process, these tensions may be applied differently and, if necessary, the tension of each holding component may be adjusted individually by at least one of the following parameters:

[0110] the position of the receiving member 550 relative to the stamp;

[0111] an offset torque of the translation guide portion of the receiving member relative to its receiving seat;

[0112] The force that resists the translation of the centering pin in the slide;

[0113] means for controlling the tilting torque of the upper guide portion; and

[0114] The shape of the borehole in the retaining member is cylindrical or rectangular, as is the maximum permissible lateral clearance of the centering pin 590 in the borehole.

[0115] These settings and the number of components to be retained for a given stamping operation are determined by experience, preliminary testing, and numerical simulation (if necessary). Once these settings are determined, they remain constant throughout the entire series of components manufactured.

[0116] Although the above-mentioned apparatus is particularly suitable for forming by stamping composite blanks having a thermoplastic matrix reinforced with continuous fibers, the appearance of wrinkles may also be associated with composite blanks of another nature when the blanks are formed into shapes including shrinkage areas, in particular thermoplastic composite materials reinforced with long (non-continuous) fibers or short fibers at the stamping temperature, or not reinforced with or reinforced by thermoplastic fibers having a certain plasticity.

[0117] The above-mentioned equipment still remains relevant to forming these other materials by stamping.

[0118] The above description and examples show that the device achieves the intended purpose, and more specifically, the device can tension thermoplastic composite blanks, especially blanks reinforced with continuous fibers that do not have the ability to plastically deform, such as carbon fibers or glass fibers, to avoid wrinkles during stamping and forming including shrinkage areas.

[0119] List of reference numerals:

[0120] 100: Final Part

[0121] 110: curved part

[0122] 150: Relative motion

[0123] 190: Gap

[0124] 200: Composite stamping blank

[0125] 210: Continuous fiber

[0126] 220: Maintenance hole

[0127] 300: Holding component

[0128] 310: Keeping the base

[0129] 320: Claw

[0130] 330: lid

[0131] 340: Two arms

[0132] 345: Groove

[0133] 350: suspension pin;

[0134] 390: Drilling

[0135] 391: Rectangular drilling

[0136] 400: Transfer frame

[0137] 410: Periphery

[0138] 411: Open Area

[0139] 450: Track

[0140] 500: Stamping die

[0141] 501: Keep component

[0142] 510: receiving base

[0143] 520: Guide upper part

[0144] 521: Horizontal axis

[0145] 522: Upper chute

[0146] 523: Downward Trough

[0147] 530: ball bearings

[0148] 540: tapered wedge

[0149] 550: Receive component

[0150] 590: Centering pin

[0151] 630: Indexing mechanism

[0152] 640: Adjustment mechanism

[0153] 641: Spring

[0154] 691: Tipping Movement

[0155] 692: Sliding Movement

[0156] 740: Wedge

[0157] 741: Second indexing mechanism

[0158] 742: Screw

[0159] 800: Movable punch

[0160] 810: Imprint

[0161] 840: Tensioner

[0162] 841: Tether

[0163] 842: Pulley

[0164] 890: Computer

[0165] 891: Force sensor

[0166] 892: Information

Claims

1. A device comprising: a stamping device comprising a stamping die and a movable punch capable of vertically moving relative to the stamping die between an open position and a closed position, the closed position defining a gap between a wall of the stamping die and a wall of the movable punch; a composite stamping blank comprising reinforcing fibers in a thermoplastic polymer matrix; a transfer frame configured to support the composite stamping blank along at least two edges of the composite stamping blank and including an open area around a periphery of the stamping die; rails for moving the transfer frame over the stamping die and between an upper position and a lower position relative to the stamping die, wherein the transfer frame comprises at least two holding members, each of the holding members being configured to hold a holding portion of the composite stamping blank on each of the at least two edges; each of the protective members including a bore configured to cooperate with a centering pin of a receiving member attached to the impact die; The stamping die comprises at least two receiving members, the receiving members being configured to cooperate with the at least two holding members so as to connect each of the holding members to each of the receiving members via the centering pin when the transfer frame is transferred from the upper position to the lower position; Each of the receiving members is attached to the stamping die by a pivotal coupling about a horizontal axis; as well as Each of the receiving members includes at least one slide groove, so that when the at least two retaining members are connected to the at least two receiving members, the at least two retaining members are guided to translate relative to the at least two receiving members within a sliding plane parallel to the horizontal axis and in a direction perpendicular to the horizontal axis.

2. The device according to claim 1, wherein The at least two retaining members are clamps.

3. The device according to claim 1, wherein The at least two retaining members include claws configured to be inserted into maintenance holes drilled on the at least two edges of the composite stamped blank.

4. The device according to claim 3, wherein The at least two retaining members include a cover covering an area where the claws are located.

5. The apparatus according to claim 1, wherein The pivotal coupling includes a first indexing mechanism configured to index the pivotal coupling into positions about the horizontal axis to receive the at least two retaining members when the transfer frame moves from the upper position to the lower position.

6. The device according to claim 5, wherein The first indexing mechanism includes an adjustable setting of de-indexing torque about the horizontal axis.

7. The apparatus according to claim 1, wherein The at least two receiving members include a spring configured to resist a force of displacement of the at least two retaining members as they translate relative to the at least two receiving members.

8. The apparatus of claim 1, comprising a ball bearing mounted on the centering pin, the ball bearing being configured to cooperate with an upper slide groove to guide the translation of each of the retaining members relative to each of the receiving members.

9. The apparatus of claim 1, comprising a tether and a tensioner configured to control a tipping torque of the at least two receiving members about the horizontal axis during a stamping process.

10. The apparatus of claim 9 , comprising a computer including a non-volatile memory including a control program for controlling the tensioner and the tipping torque based on parameters measured during the punching process, the parameters selecting between the displacement of the movable punch and the force applied to the movable punch.

11. The apparatus according to claim 1, wherein The reinforcing fibers are selected from the group consisting of continuous fibers, long fibers and short fibers.

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