Mold tool for forming multi-flanging thermoplastic composite material corner piece and forming method

Abstract

The invention discloses a mold tool for forming a multi-flanging thermoplastic composite material corner piece and a forming method. The mold tool comprises a lower mold and an upper mold, the lower die comprises a lower forming table, the top surface of the lower forming table is a forming table surface, the forming table surface is provided with a first push block capable of horizontally moving in the front-back direction, and is also provided with a second push block and a third push block capable of horizontally moving in the left-right direction, and the rear side surface of the second push block is attached to the front side surface of the third push block; the upper die comprises an upper operation table used for being connected with a pressing machine, an upper die core is fixed to the bottom face of the upper operation table, and the upper die core can vertically move up and down along with the upper operation table. The first rear turned edge, the side turned edge and the second rear turned edge formed through the mold tool are not prone to springback, and the first push block, the second push block and the third push block in the mold tool do not collide and interfere with each other.

Description

Technical Field

[0001] This invention belongs to the field of thermoplastic composite material molding technology, specifically relating to a mold tooling and molding method for molding multi-flanged thermoplastic composite corner pieces. Background Technology

[0002] Thermoplastic composites are composite materials that use thermoplastic resin as the continuous phase (matrix) and fibers or particles as reinforcement materials. Compared with thermosetting composites, thermoplastic composites have advantages such as good toughness, high fatigue strength, high impact damage tolerance, short molding cycle, easy storage, and recyclability. Currently, various high-performance continuous fiber reinforced thermoplastic composites have been tested or used in various types of aircraft. For example, the Airbus A350XWB uses more than 5,000 thermoplastic composite corner pieces with more than 2,000 different configurations. To meet production capacity requirements, hot stamping technology is used to form the thermoplastic composite corner pieces. The main process steps include: transferring the thermoplastic composite blank from the worktable to an oven for heating; removing the softened thermoplastic composite blank from the oven and transferring it to a press for forming; and removing the formed part from the press for trimming and machining.

[0003] In traditional metal corner molding, the good ductility of metal can be used to form a variety of complex structures. However, in the molding of thermoplastic composite corner pieces, due to the presence of reinforcing materials such as fibers in the thermoplastic composite material, the deformation of the thermoplastic composite material is constrained by the fibers and can only undergo very limited deformation. In the molding process of complex thermoplastic composite corner pieces, defects such as insufficient glue, fiber buckling, and wrinkles are prone to occur.

[0004] Among them, the apex-open type multi-flanged thermoplastic composite corner piece is a type of composite configuration. It integrates a lateral support structure on the basis of the L-shaped corner piece, thereby improving the local structural stiffness. Its basic configuration is shown in the attached figure. Figure 1As shown, the multi-flanged thermoplastic composite corner piece 1 includes a base plate 101, a rear first flange 102, a rear second flange 103, and a side flange 104. The rear first flange 102 and the side flange 104 are both perpendicularly connected to the base plate 101, and the rear first flange 102 is perpendicular to the side flange 104. The rear second flange 103 is flush with the rear first flange 102 and perpendicularly connected to the side flange 104. The gap between the rear first flange 102 and the rear second flange 103 forms a apex corner opening 105. The molding of such complex thermoplastic composite corner pieces involves bending, and the resulting flanges are prone to springback, resulting in the flange angle not meeting the requirements. Furthermore, the flanges of these thermoplastic composite corner pieces are perpendicular to each other, requiring multiple bending steps instead of a single molding process. This results in complex mold and tooling structures, and the possibility of mold collisions and interference during the step-by-step bending process. Additionally, the thermoplastic composite sheet blanks used in the molding process need to be heated in an oven before hot stamping. The temperature and heating time control affect the temperature uniformity of the thermoplastic composite sheet blanks, and the heating time varies depending on the thickness of the sheet blank. Excessive heating temperature and time can lead to thermal degradation of the surface material, while insufficient heating temperature and time can prevent the internal material from reaching the specified temperature, affecting subsequent hot stamping. The control of the heating rate affects the thermal history of the material in the oven, thus affecting the actual state of the thermoplastic composite sheet blank. During hot stamping, relative sliding will occur between the layers of the thermoplastic composite sheet blank. If the temperature of the thermoplastic composite sheet blank is too low, the sliding ability will be insufficient, and wrinkles will easily occur. If the temperature of the thermoplastic composite sheet blank is too high, excessive sliding will occur, which will lead to fiber buckling, such as layup or excessive fiber deflection. In addition, the molding pressure of hot stamping plays a decisive role in the porosity of the formed thermoplastic composite sheet. If the molding pressure is too low, the porosity of the formed thermoplastic composite sheet will be high, which will affect its mechanical properties. If the molding pressure is too high, it will be easy to have poor resin, that is, thermoplastic resin will overflow, which will affect the thickness uniformity and fiber volume fraction uniformity of the formed thermoplastic composite sheet. The control of the loading rate of the molding pressure affects the molding quality and molding rate of the thermoplastic composite sheet. Summary of the Invention

[0005] In view of the above-mentioned defects of the prior art, the present invention provides a mold tooling and molding method for forming multi-flanged thermoplastic composite corner pieces. The rear first flange, side flange and rear second flange formed by the mold tooling are not prone to springback, and the first push block, second push block and third push block in the mold tooling will not collide or interfere with each other.

[0006] The technical solution adopted by this invention to solve its technical problem is:

[0007] A mold tooling for molding multi-flanged thermoplastic composite corner pieces includes a lower mold and an upper mold. The lower mold includes a lower forming platform, the top surface of which is a forming table surface. The forming table surface is provided with a first push block that can move horizontally in the front-back direction, and a second push block and a third push block that can move horizontally in the left-right direction. The rear side of the second push block is in contact with the front side of the third push block. The upper mold includes an upper operating table for connecting to a press. An upper mold core is fixed on the bottom surface of the upper operating table. The upper mold core can move vertically up and down with the upper operating table.

[0008] The upper mold core and the first push block cooperate once to preform the rear first flange of the multi-flanged thermoplastic composite corner piece, and cooperate once with the second push block to preform the side flange and cooperate with the forming table to form the base plate. The first push block and the upper mold core cooperate twice to form the rear first flange. The second push block and the upper mold core cooperate twice to form the side flange. The third push block cooperates with the second push block and the upper mold core to preform the rear second flange. The first push block and the upper mold core cooperate thrice to form the rear second flange.

[0009] Furthermore, the lower forming platform is provided with multiple parallel and equally spaced forming platform heat conduction oil pipes, the first push block is provided with multiple parallel and equally spaced first push block heat conduction oil pipes, the second push block is provided with multiple parallel and equally spaced second push block heat conduction oil pipes, the third push block is provided with multiple parallel and equally spaced third push block heat conduction oil pipes, and the upper mold core is provided with multiple parallel and equally spaced upper mold core heat conduction oil pipes.

[0010] Furthermore, it also includes a temperature detection device and a mold temperature controller. The temperature detection device is connected to the signal input terminal of the mold temperature controller, and the mold temperature controller is connected to the heat transfer oil lines of each molding table, each first push block, each second push block, each third push block, and each upper mold core. The temperature detection device is used to detect the temperature of the molding table, the pressing surface temperature of the first push block, the pressing surface temperature of the second push block, the pressing surface temperature of the third push block, and the stamping surface temperature of the upper mold core, and transmits the detected temperature to the mold temperature controller. The mold temperature controller is used to compare the received temperature with a pre-stored target temperature, adjust the temperature of the heat transfer oil according to the comparison result, and deliver the heat transfer oil to each of the molding table heat transfer oil lines, each of the first push block heat transfer oil lines, each of the second push block heat transfer oil lines, each of the third push block heat transfer oil lines, and each upper mold core heat transfer oil line.

[0011] Furthermore, the first push block is driven to move horizontally in the front-back direction by the first hydraulic rod, the second push block is driven to move horizontally in the left-right direction by the second hydraulic rod, and the third push block is driven to move horizontally in the left-right direction by the third hydraulic rod.

[0012] Furthermore, the upper mold core moves downward into place, and the bottom surface of the upper operating table is in contact with the top surfaces of the first push block, the second push block, and the third push block.

[0013] A method for molding multi-flanged thermoplastic composite corner pieces, using the aforementioned mold fixture for molding multi-flanged thermoplastic composite corner pieces, includes the following steps:

[0014] S1. The thermoplastic composite material sheet blank is heated and softened, wherein the thermoplastic composite material sheet blank is provided with a first bending auxiliary line, a second bending auxiliary line and a third bending auxiliary line;

[0015] S2-1. The heated and softened thermoplastic composite material sheet blank is moved above the first push block, the second push block and the third push block, wherein the first bending auxiliary line is perpendicular to the moving direction of the first push block, the second bending auxiliary line is perpendicular to the moving direction of the second push block, and the third bending auxiliary line is parallel to the moving direction of the third push block.

[0016] S2-2. Control the first push block to move backward to the first limit position, so that the first bending auxiliary line is in front of the first push block; control the second push block to move left to the second limit position, so that the second bending auxiliary line is in the right side of the second push block.

[0017] S2-3. The upper operating table is controlled by the press to drive the upper mold core to punch downward. After the upper mold core punches downward, it cooperates with the first push block to pre-bend the thermoplastic composite material sheet blank along the first bending auxiliary line to pre-form the rear first flange. It also cooperates with the second push block to pre-bend the thermoplastic composite material sheet blank along the second bending auxiliary line to pre-form the side flange, and cooperates with the forming table to form the base plate.

[0018] S2-4. Control the first push block to move forward to push the pre-formed rear first flange forward to the upper mold core to form the rear first flange, and control the second push block to move to the right to push the pre-formed side flange to the right to the upper mold core to form the side flange.

[0019] S2-5. Control the first push block to move backward to the first limit position while keeping the position of the second push block unchanged, and then control the third push block to move to the right. The third push block, together with the second push block and the upper mold core, makes the thermoplastic composite material sheet blank pre-bend along the third bending auxiliary line to pre-form the rear second flange.

[0020] S2-6. Control the third push block to move to the left and reset, then control the first push block to move forward to push the pre-formed rear second flange forward to the upper mold core to form the rear second flange and complete the forming of the multi-flange thermoplastic composite corner piece.

[0021] Furthermore, the front-to-back horizontal distance between the first limiting position in step S2-2 and the first rear flange formed in step S2-4 is 40mm, the left-to-right horizontal distance between the second limiting position in step S2-2 and the side flange formed in step S2-4 is 40mm, the pre-bending angle of the pre-formed first rear flange relative to the formed base plate in step S2-3 is 70°-80°, and the pre-bending angle of the pre-formed side flange relative to the formed base plate in step S2-3 is 70°-80°.

[0022] Furthermore,

[0023] Before step S1, the following steps are also included: First, select a thermoplastic composite material sheet with continuous carbon fiber reinforced polyetheretherketone and a thickness of 1mm-6mm. Then, cut the thermoplastic composite material sheet according to the size of the formed multi-flanged thermoplastic composite material corner piece to obtain a thermoplastic composite material sheet blank. Then, fix the cut thermoplastic composite material sheet blank onto a polyimide film. After that, the polyimide film is tensioned by a film tension system, and the two ends of the tensioned imide film are clamped onto the transfer frame by pneumatic clamps.

[0024] Step S1 specifically involves transferring the transfer frame into an oven using a robotic arm to heat and soften the thermoplastic composite material sheet blank.

[0025] Furthermore,

[0026] In step S1: the oven is an infrared heating furnace, and the heating temperature of the infrared heating furnace is set to 330℃-430℃.

[0027] The heating rate is set to 30℃ / min-150℃ / min, and the holding time is set to 5s-100s;

[0028] In step S2-1: After the thermoplastic composite material sheet blank is heated and softened, the polyimide film along with the thermoplastic composite material sheet blank is transferred to the top of the first push block, the second push block and the third push block by a robotic arm through the transfer frame.

[0029] In steps S2-3: After the upper mold core moves downward into place and completes the mold closing between the upper and lower molds, the upper mold core is pressurized by a press at a rate of 50T / s-800T / s and pressurized to the set pressure value of 50KN-800KN to complete the downward punching of the upper mold core;

[0030] In steps S2-4: After the first push block moves forward into position, it is pressurized at a rate of 50T / s-800T / s to a set pressure value of 50KN-800KN and then held for 5s-60s to complete the forming of the rear first flange. After the second push block moves to the right into position, it is pressurized at a rate of 50T / s-800T / s to a set pressure value of 50KN-800KN and then held for 5s-60s to complete the forming of the side flange. During the forming of the rear first flange and the side flange, the upper mold core is held under a pressure value of 50KN-800KN.

[0031] In steps S2-5: during the pre-forming process of the rear second flange, the second push block and the upper mold core are respectively subjected to pressure values ​​of 50KN-800KN;

[0032] In steps S2-6: After the first push block moves forward into place, the first push block is pressurized at a rate of 50T / s-800T / s and pressurized to the set pressure value of 50KN-800KN, and then the pressure is held for 5s-60s to complete the forming of the rear second flange. During the forming of the rear second flange, the upper mold core is held under a pressure value of 50KN-800KN.

[0033] Furthermore,

[0034] It also includes step S3: first, the upper operating table is controlled by the press to drive the upper mold core to move upward, and then the formed multi-flanged thermoplastic composite corner piece is removed from the polyimide film and naturally cooled to room temperature;

[0035] It also includes step S4: cutting, grinding and sealing the edges of the multi-flanged thermoplastic composite corner piece according to the actual size of the formed multi-flanged thermoplastic composite corner piece.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] The mold tooling for forming multi-flanged thermoplastic composite corner pieces in this invention includes a lower mold and an upper mold; the lower mold includes a lower forming platform, the top surface of which is a forming platform surface, and a first push block that can move horizontally in the front-back direction is provided on the forming platform surface, and a second push block and a third push block that can move horizontally in the left-right direction are provided, with the rear side of the second push block and the front side of the third push block fitting together; the upper mold includes an upper operating platform for connecting to a press, and an upper mold core is fixed on the bottom surface of the upper operating platform, which can move vertically up and down with the upper operating platform. In this invention, the rear first flange, side flange, and rear second flange of the multi-flanged thermoplastic composite corner piece are all pre-formed before being formed. Specifically, the upper mold core and the first push block engage once to pre-form the rear first flange, and simultaneously, the upper mold core and the second push block engage once to pre-form the side flange. The first push block and the upper mold core engage a second time to form the rear first flange, compensating for the pre-bending angle of the rear first flange during pre-forming, ensuring that the bending angle of the rear first flange is within the corresponding theoretical error. Similarly, the second push block and the upper mold core engage a second time to form the side flange, compensating for the pre-bending angle of the side flange during pre-forming, ensuring that the bending angle of the side flange is within the corresponding theoretical error. Within the tolerance range, the third push block, in conjunction with the second push block and the upper mold core, can pre-form the rear second flange, while the first push block, in conjunction with the upper mold core three times, can form the rear second flange. This compensates for the pre-bending angle of the rear second flange during pre-forming, ensuring that the bending angle of the rear second flange is within the corresponding theoretical tolerance. Therefore, the rear first flange, side flange, and rear second flange formed using this mold fixture are less prone to springback. Furthermore, the structural design of this mold fixture allows the rear first flange, side flange, and rear second flange in multi-flange thermoplastic composite corner pieces to be bent and formed sequentially, without collision or interference between the first push block, second push block, and third push block during movement.

[0038] In this invention, the lower molding platform is provided with multiple parallel and equally spaced molding platform heat-conducting oil pipes, the first push block is provided with multiple parallel and equally spaced first push block heat-conducting oil pipes, the second push block is provided with multiple parallel and equally spaced second push block heat-conducting oil pipes, the third push block is provided with multiple parallel and equally spaced third push block heat-conducting oil pipes, and the upper mold core is provided with multiple parallel and equally spaced upper mold core heat-conducting oil pipes. The mold tooling also includes a temperature detection component and a mold temperature controller. The temperature detection component is connected to the signal input terminal of the mold temperature controller, and the mold temperature controller is connected to each molding platform heat-conducting oil pipe, each first push block heat-conducting oil pipe, each second push block heat-conducting oil pipe, each third push block heat-conducting oil pipe, and each upper mold core heat-conducting oil pipe. This system uses a mold temperature controller to maintain the temperature of the heat transfer oil within a set range. The heat transfer oil, operating within this range, is then delivered to the heat transfer oil lines of each molding table, each first ejector block, each second ejector block, each third ejector block, and each upper mold core. This heats the molding table, the first ejector blocks, the second ejector blocks, the third ejector blocks, and the upper mold core. Temperature sensors can detect the temperatures of the molding table, the pressing surfaces of the first, second, and third ejector blocks, and the stamping surfaces of the upper mold core. The detected temperatures can be recorded. The temperature is transmitted to the mold temperature controller, which compares the received temperature with the pre-stored target temperature and adjusts the temperature of the heat transfer oil accordingly based on the comparison result. This ensures that the temperatures of the molding table, the pressing surfaces of the first, second, and third push blocks, and the stamping surfaces of the upper mold core all reach the required temperatures and that the temperature is uniform. This reduces the thermal stress on the bottom plate, the first rear flange, the second rear flange, and the side flanges of the multi-flanged thermoplastic composite corner piece during the molding process, thereby reducing defects such as warping and springback in the multi-flanged thermoplastic composite corner piece. Attached Figure Description

[0039] Figure 1 A schematic diagram of the structure of a multi-flanged thermoplastic composite corner piece;

[0040] Figure 2 This is a schematic diagram of how a thermoplastic composite material sheet blank is bent sequentially to form a multi-flanged thermoplastic composite material corner piece in this invention.

[0041] Figure 3 This is a schematic diagram of the structure of the mold tooling for forming multi-flanged thermoplastic composite corner pieces of the present invention, in which the upper mold core is controlled by a press to punch downwards;

[0042] Figure 4 This is a schematic diagram of the structure of the mold tooling for forming multi-flanged thermoplastic composite corner pieces of the present invention, which controls the third push block to move to the right to pre-form the rear second flange and hide the upper mold core.

[0043] Figure 5 This is a schematic diagram of the structure of a multi-flanged thermoplastic composite corner piece formed using the mold tooling of the present invention, with the upper mold core hidden.

[0044] Explanation of reference numerals in the figure: 1. Multi-flanged thermoplastic composite corner piece; 101. Base plate; 102. First rear flange; 103. Second rear flange; 104. Side flange; 105. Top corner opening; 2. Thermoplastic composite sheet blank; 201. First bending auxiliary line; 202. Second bending auxiliary line; 203. Third bending auxiliary line; 301. Lower forming table; 30101. Forming table surface; 302. First push block; 303. Second push block; 304. Third push block; 305. Upper operating table; 306. Upper mold core; 307. Forming table surface heat transfer oil pipe; 308. First push block heat transfer oil pipe; 309. Second push block heat transfer oil pipe; 3010. First hydraulic rod; 3011. Second hydraulic rod; 3012. Third hydraulic rod; 3013. Second limit position. Detailed Implementation

[0045] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0046] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0047] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0048] Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0049] A mold tooling for molding multi-flanged thermoplastic composite corner pieces, such as Figure 1 As shown, the multi-flanged thermoplastic composite corner piece 1 includes a base plate 101, a rear first flange 102, a rear second flange 103, and a side flange 104. The rear first flange 102 and the side flange 104 are both perpendicularly connected to the base plate 101, and the rear first flange 102 is perpendicular to the side flange 104. The rear second flange 103 is flush with the rear first flange 102 and perpendicularly connected to the side flange 104. The gap between the rear first flange 102 and the rear second flange 103 forms a apex corner opening 105.

[0050] like Figures 3-5 As shown, the mold fixture includes a lower mold and an upper mold; the lower mold includes a lower forming platform 301, the top surface of which is a forming platform 30101, and the forming platform 30101 is provided with a first push block 302 that can move horizontally in the front-back direction, and a second push block 303 and a third push block 304 that can move horizontally in the left-right direction, the rear side of the second push block 303 and the front side of the third push block 304 are in contact; the upper mold includes an upper operating platform 305 for connection with a press via a connecting plate, and an upper mold core 306 is fixed on the bottom surface of the upper operating platform 305, the upper mold core 306 can move vertically up and down with the upper operating platform 305;

[0051] The upper mold core 306 and the first push block 302 cooperate once to preform the first flange 102 at the rear and cooperate once with the second push block 303 to preform the side flange 104 and cooperate with the forming table 30101 to form the base plate 101. The first push block 302 and the upper mold core 306 cooperate a second time to form the first flange 102 at the rear. The second push block 303 and the upper mold core 306 cooperate a second time to form the side flange 104. The third push block 304 cooperates with the second push block 303 and the upper mold core 306 to preform the second flange 103 at the rear. The first push block 302 and the upper mold core 306 cooperate a third time to form the second flange 103 at the rear.

[0052] In this invention, the rear first flange 102, side flange 104, and rear second flange 103 of the multi-flanged thermoplastic composite corner piece 1 are all pre-formed before being formed. Specifically, the upper mold core 306 and the first push block 302 cooperate once to pre-form the rear first flange 102, and the upper mold core 306 and the second push block 303 cooperate once to pre-form the side flange 104. The first push block 302 and the upper mold core 306 cooperate a second time to form the rear first flange 102, compensating for the pre-bending angle of the rear first flange 102 during pre-forming, ensuring that the bending angle of the rear first flange 102 is within the corresponding theoretical error. Similarly, the second push block 303 and the upper mold core 306 cooperate a second time to form the side flange 104, compensating for the pre-bending angle of the side flange 104 during pre-forming, ensuring that the bending angle of the side flange 104 is within the corresponding theoretical error. Within the theoretical error range, the third pusher 304, in conjunction with the second pusher 303 and the upper mold core 306, can pre-form the rear second flange 103. The first pusher 302, in conjunction with the upper mold core 306 three times, can form the rear second flange 103 to compensate for the pre-bending angle of the rear second flange 103 during pre-forming, so that the bending angle of the rear second flange 103 can reach within the corresponding theoretical error range. Therefore, the rear first flange 102, side flange 104 and rear second flange 103 formed by this mold tooling are not prone to springback. In addition, the structural design of this mold tooling allows the rear first flange 102, side flange 104 and rear second flange 103 in the multi-flange thermoplastic composite corner piece 1 to be bent and formed in sequence. The first pusher 302, second pusher 303 and third pusher 304 will not collide or interfere during movement.

[0053] In one embodiment,

[0054] like Figures 3-5 As shown, the lower forming platform 301 is provided with multiple parallel and equally spaced forming platform heat conduction oil pipes 307, the first push block 302 is provided with multiple parallel and equally spaced first push block heat conduction oil pipes 308, the second push block 303 is provided with multiple parallel and equally spaced second push block heat conduction oil pipes 309, the third push block 304 is provided with multiple parallel and equally spaced third push block 304 heat conduction oil pipes, and the upper mold core 306 is provided with multiple parallel and equally spaced upper mold core heat conduction oil pipes.

[0055] The mold fixture also includes a temperature detection component and a mold temperature controller. The temperature detection component is connected to the signal input terminal of the mold temperature controller. The mold temperature controller is connected to the heat transfer oil lines 307, 308, 309, 304, and 305 of each molding table, and the upper mold core. The temperature detection component is used to monitor the temperature of the molding table 30101, the pressing surface temperature of the first pusher 302, the pressing surface temperature of the second pusher 303, and the pressing surface temperature of the third pusher 304. The temperature of the pressing surface of block 304 and the stamping surface of upper mold core 306 are detected, and the detected temperature is transmitted to the mold temperature controller. The mold temperature controller is used to compare the received temperature with the pre-stored target temperature, and adjust the temperature of the heat transfer oil according to the comparison result. It is also used to deliver the heat transfer oil to the heat transfer oil pipes 307 of each molding table, the heat transfer oil pipes 308 of each first push block, the heat transfer oil pipes 309 of each second push block, the heat transfer oil pipes 304 of each third push block, and the heat transfer oil pipes of each upper mold core.

[0056] In this way, the temperature of the heat transfer oil is controlled within a set temperature range by a mold temperature controller, and the heat transfer oil within the set temperature range is delivered to the heat transfer oil pipes 307 of each molding table, 308 of each first push block, 309 of each second push block, 304 of each third push block, and 306 of each upper mold core, so as to achieve heating of the molding table 30101, the first push block 302, the second push block 303, the third push block 304, and the upper mold core 306. The temperature of the molding table 30101, the pressing surface temperature of the first push block 302, the pressing surface temperature of the second push block 303, the pressing surface temperature of the third push block 304, and the stamping surface temperature of the upper mold core 306 can be detected by temperature detection devices. The system can transmit the detected temperature to the mold temperature controller, which compares the received temperature with the pre-stored target temperature and adjusts the temperature of the heat transfer oil accordingly based on the comparison result. This ensures that the temperatures of the molding table 30101, the pressing surface of the first push block 302, the pressing surface of the second push block 303, the pressing surface of the third push block 304, and the stamping surface of the upper mold core 306 all reach the required temperatures and ensure temperature uniformity. This reduces the thermal stress of the base plate 101, the rear first flange 102, the rear second flange 103, and the side flange 104 of the multi-flanged thermoplastic composite corner piece 1 during the molding process, thereby reducing warping deformation and springback defects of the multi-flanged thermoplastic composite corner piece 1.

[0057] Preferably, the temperature detection element is a temperature monitoring instrument.

[0058] Preferably, the diameter of the heat transfer oil pipe 307 on the molding table is 20mm and the vertical distance between it and the molding table 30101 is 40mm, and the distance between two adjacent heat transfer oil pipes 307 on the molding table is 50mm.

[0059] In one embodiment, such as Figures 3-5 As shown, the first push block 302 is driven to move horizontally in the front-back direction by the first hydraulic rod 3010, the second push block 303 is driven to move horizontally in the left-right direction by the second hydraulic rod 3011, and the third push block 304 is driven to move horizontally in the left-right direction by the third hydraulic rod 3012.

[0060] Thus, the first push block 302, driven by the first hydraulic rod 3010, can control the lateral pressure to ensure the uniformity of the thickness of the rear first flange 102 and the rear second flange 103 of the multi-flanged thermoplastic composite corner piece 1. The second push block 303, driven by the second hydraulic rod 3011, can control the lateral pressure to ensure the uniformity of the thickness of the side flange 104 of the multi-flanged thermoplastic composite corner piece 1.

[0061] In one embodiment, the upper mold core 306 moves downward into place, and the bottom surface of the upper operating table 305 is in contact with the top surfaces of the first push block 302, the second push block 303, and the third push block 304.

[0062] A method for molding multi-flanged thermoplastic composite corner pieces, using the aforementioned mold fixture for molding multi-flanged thermoplastic composite corner pieces, includes the following steps:

[0063] S1. The thermoplastic composite material sheet blank 2 is heated and softened, wherein the thermoplastic composite material sheet blank 2 is provided with a first bending auxiliary line 201, a second bending auxiliary line 202 and a third bending auxiliary line 203, see Figure 2 ;

[0064] S2-1. Move the heated and softened thermoplastic composite material sheet blank 2 above the first push block 302, the second push block 303, and the third push block 304, wherein the first bending auxiliary line 201 is perpendicular to the moving direction of the first push block 302, the second bending auxiliary line 202 is perpendicular to the moving direction of the second push block 303, and the third bending auxiliary line 203 is parallel to the moving direction of the third push block 304. (See...) Figure 3 ;

[0065] S2-2, Control the first push block 302 to move backward to the first limit position, so that the first bending auxiliary line 201 is in front of the first push block 302; Control the second push block 303 to move left to the second limit position 3013, so that the second bending auxiliary line 202 is in the right side of the second push block 303.

[0066] S2-3. The upper operating table 305 of the press controls the upper mold core 306 to press downward. After the upper mold core 306 presses downward, it cooperates with the first push block 302 to pre-bend the thermoplastic composite material sheet blank 2 along the first bending auxiliary line 201 to pre-form the rear first flange 102. It also cooperates with the second push block 303 to pre-bend the thermoplastic composite material sheet blank 2 along the second bending auxiliary line 202 to pre-form the side flange 104. It also cooperates with the forming table 30101 to form the base plate 101.

[0067] S2-4. Control the first push block 302 to move forward to push the pre-formed rear first flange 102 forward to the upper mold core 306 to form the rear first flange 102, compensate for the springback angle of the rear first flange 102, so that the bending angle of the rear first flange 102 relative to the base plate 101 reaches 90°, and control the second push block 303 to move to the right to push the pre-formed side flange 104 to the right to the upper mold core 306 to form the side flange 104, compensate for the springback angle of the side flange 104, so that the bending angle of the side flange 104 relative to the base plate 101 reaches 90°.

[0068] S2-5, Control the first push block 302 to move backward to the first limit position while keeping the position of the second push block 303 unchanged, such as Figure 4 As shown, the third push block 304 is then controlled to move to the right. The third push block 304, together with the second push block 303 and the upper mold core 306, causes the thermoplastic composite material sheet blank 2 to be pre-bent along the third bending auxiliary line 203 to pre-form the rear second flange 103.

[0069] S2-6. Control the third pusher block 304 to move to the left and reset, then control the first pusher block 302 to move forward to push the pre-formed rear second flange 103 forward to the upper mold core 306, so as to form the rear second flange 103, compensate for the springback angle of the rear second flange 103, and make the bending angle of the rear second flange 103 relative to the base plate 101 reach 90°, thus completing the forming of the multi-flanged thermoplastic composite corner piece 1. See Figure 5 .

[0070] In one embodiment, the front-to-back horizontal distance between the first limiting position in step S2-2 and the formed rear first flange 102 in step S2-4 is 40mm, the left-to-right horizontal distance between the second limiting position 3013 in step S2-2 and the formed side flange 104 in step S2-4 is 40mm, the pre-bending angle of the pre-formed rear first flange 102 relative to the formed base plate 101 in step S2-3 is 70°-80°, and the pre-bending angle of the pre-formed side flange 104 relative to the formed base plate 101 in step S2-3 is 70°-80°.

[0071] By setting the front-to-back horizontal distance between the first limiting position in step S2-2 and the formed rear first flange 102 in step S2-4 to 40mm, it can be ensured that after the upper mold core 306 punches downward in step S2-3, it cooperates with the first push block 302 to pre-bend the thermoplastic composite material sheet blank 2 along the first bending auxiliary line 201 to pre-form the rear first flange 102, and the pre-bending angle of the pre-formed rear first flange 102 relative to the formed base plate 101 in step S2-3 can reach 70°-80°. °; By setting the horizontal distance between the second limiting position 3013 in step S2-2 and the side flange 104 formed in step S2-4 to 40mm, it can be ensured that after the upper mold core 306 in step S2-3 is pressed downward, it cooperates with the second push block 303 to pre-bend the thermoplastic composite material sheet blank 2 along the second bending auxiliary line 202 to pre-form the side flange 104, and the pre-bending angle of the pre-formed side flange 104 relative to the formed base plate 101 in step S2-3 can reach 70°-80°.

[0072] In one embodiment,

[0073] The following steps are included before step S1:

[0074] First, select a thermoplastic composite material sheet with continuous carbon fiber reinforced polyetheretherketone and a thickness of 1mm-6mm. Then, cut the thermoplastic composite material sheet according to the size of the formed multi-flanged thermoplastic composite corner piece 1 to obtain a thermoplastic composite material sheet blank 2. Then, place the cut thermoplastic composite material sheet blank 2 on a polyimide film and fix it with polyimide tape. Then, tension the polyimide film through a film tension system and clamp both ends of the tensioned imide film on the transfer frame using pneumatic clamps.

[0075] The mold temperature controller is connected to the heat transfer oil lines 307, 308, 309, 304, and 306 of each molding table, first push block, and upper mold core. Based on the molding temperature, the mold temperature controller maintains the temperature of the heat transfer oil within 200℃-300℃ and delivers the heat transfer oil to these lines. This heat transfer oil heats the molding table 30101, first push block 302, second push block 303, third push block 304, and upper mold core 306. A temperature monitoring device is used to monitor the temperature of the molding table 30101 and the first push block 302. The temperatures of the pressing surfaces of the first, second, and third push blocks 303, as well as the stamping surfaces of the upper mold core 306, are monitored. After the temperatures stabilize, the temperatures of the molding table 30101, the first push block 302, the second push block 303, the third push block 304, and the upper mold core 306 are measured, and the measured temperatures are transmitted to the mold temperature controller. The mold temperature controller compares the received temperatures with the pre-stored target temperatures and adjusts the temperature of the heat transfer oil accordingly based on the comparison results to ensure that the temperatures of the molding table 30101, the first push block 302, the second push block 303, the third push block 304, and the upper mold core 306 are all within ±5 ℃ of the target temperature and to ensure temperature uniformity.

[0076] Step S1 specifically involves transferring the transfer frame into an oven using a robotic arm to heat and soften the thermoplastic composite material sheet blank 2.

[0077] in,

[0078] In step S1: the oven is an infrared heating furnace, the heating temperature of the infrared heating furnace is set to 330℃-430℃, the heating rate is set to 30℃ / min-150℃ / min, and the holding time is set to 5s-100s;

[0079] In step S2-1: After the thermoplastic composite material sheet blank 2 is heated and softened, the polyimide film along with the thermoplastic composite material sheet blank 2 is transferred to the top of the first push block 302, the second push block 303 and the third push block 304 by a robotic arm through a transfer frame.

[0080] In steps S2-3: After the upper mold core 306 moves downward into place and completes the mold closing between the upper and lower molds, the upper mold core 306 is pressurized by the press at a rate of 50T / s-800T / s and pressurized to the set pressure value of 50KN-800KN to complete the downward punching of the upper mold core 306.

[0081] In steps S2-4: After the first push block 302 moves forward into position, it is pressurized at a rate of 50T / s-800T / s to a set pressure value of 50KN-800KN and then held for 5s-60s to complete the forming of the rear first flange 102. After the second push block 303 moves to the right into position, it is pressurized at a rate of 50T / s-800T / s to a set pressure value of 50KN-800KN and then held for 5s-60s to complete the forming of the side flange 104. During the forming of the rear first flange 102 and the side flange 104, the upper mold core 306 is held under a pressure value of 50KN-800KN.

[0082] In steps S2-5: During the pre-forming process of the rear second flange 103, the second push block 303 and the upper mold core 306 are held under pressure values ​​of 50KN-800KN respectively;

[0083] In steps S2-6: After the first push block 302 moves forward into place, the first push block 302 is pressurized at a rate of 50T / s-800T / s and pressurized to the set pressure value of 50KN-800KN, and then held for 5s-60s to complete the forming of the rear second flange 103. During the forming of the rear second flange 103, the upper mold core 306 is held under a pressure value of 50KN-800KN.

[0084] By setting the heating temperature of the infrared heating furnace to 330℃-430℃, the heating rate to 30℃ / min-150℃ / min, and the holding time to 5s-100s, the temperature uniformity of the thermoplastic composite material blank 2, which is made of continuous carbon fiber reinforced polyetheretherketone and has a thickness of 1mm-6mm, can be guaranteed. This ensures that wrinkles or fiber buckling are not easily generated during the subsequent hot stamping process, thus guaranteeing the subsequent hot stamping effect.

[0085] In step S2-3, the pressure applied to the upper mold core 306 is limited; in step S2-4, the pressure and holding time of the first push block 302 are limited; and in step S2-6, the pressure and holding time of the first push block 302 are limited. This ensures the porosity and mechanical properties of the formed multi-flanged thermoplastic composite corner piece 1, prevents the occurrence of insufficient glue, and ensures the uniformity of the thickness and fiber volume fraction of the formed multi-flanged thermoplastic composite corner piece 1. In addition, by setting the loading rate of the upper mold core 306, the first push block 302, and the second push block 303 to 50T / s-800T / s, the forming quality and forming rate of the formed multi-flanged thermoplastic composite corner piece 1 are ensured.

[0086] in,

[0087] It also includes step S3: first, the upper operating table 305 is controlled by the press to drive the upper mold core 306 to move upward, and then the formed multi-flanged thermoplastic composite corner piece 1 is removed from the polyimide film and naturally cooled to room temperature;

[0088] It also includes step S4: cutting, grinding and sealing the edges of the multi-flanged thermoplastic composite corner piece 1 according to the actual size of the formed multi-flanged thermoplastic composite corner piece 1.

[0089] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A mold tooling for molding multi-flanged thermoplastic composite corner pieces, characterized in that: The system includes a lower mold and an upper mold. The lower mold includes a lower forming platform (301), the top surface of which is a forming platform (30101). The forming platform (30101) is provided with a first push block (302) that can move horizontally in the front-back direction, and a second push block (303) and a third push block (304) that can move horizontally in the left-right direction. The rear side of the second push block (303) is in contact with the front side of the third push block (304). The upper mold includes an upper operating platform (305) for connecting to a press. An upper mold core (306) is fixed on the bottom surface of the upper operating platform (305). The upper mold core (306) can move vertically up and down with the upper operating platform (305). The upper mold core (306) is used in a first-order combination with the first push block (302) to preform the rear first flange (102) of the multi-flanged thermoplastic composite corner piece (1) and in a first-order combination with the second push block (303) to preform the side flange (104) and in a combination with the molding table (30101) to form the base plate (101). The first push block (302) is used in a second-order combination with the upper mold core (306) to form the rear first flange (102). The second push block (303) is used in a second-order combination with the upper mold core (306) to form the side flange (104). The third push block (304) is used in a combination with the second push block (303) and the upper mold core (306) to preform the rear second flange (103). The first push block (302) is used in a third-order combination with the upper mold core (306) to form the rear second flange (103).

2. The mold tooling for forming multi-flanged thermoplastic composite corner pieces according to claim 1, characterized in that: The lower forming platform (301) is provided with a plurality of parallel and equally spaced forming platform heat conduction oil pipes (307), the first push block (302) is provided with a plurality of parallel and equally spaced first push block heat conduction oil pipes (308), the second push block (303) is provided with a plurality of parallel and equally spaced second push block heat conduction oil pipes (309), the third push block (304) is provided with a plurality of parallel and equally spaced third push block (304) heat conduction oil pipes, and the upper mold core (306) is provided with a plurality of parallel and equally spaced upper mold core heat conduction oil pipes.

3. The mold tooling for forming multi-flanged thermoplastic composite corner pieces according to claim 2, characterized in that: It also includes a temperature sensing element and a mold temperature controller. The temperature sensing element is connected to the signal input terminal of the mold temperature controller. The mold temperature controller is connected to the heat transfer oil lines (307) of each molding table, the heat transfer oil lines (308) of each first push block, the heat transfer oil lines (309) of each second push block, the heat transfer oil lines (304) of each third push block, and the heat transfer oil lines of each upper mold core. The temperature sensing element is used to monitor the temperature of the molding table (30101), the pressing surface temperature of the first push block (302), the pressing surface temperature of the second push block (303), and the pressing surface temperature of the third push block (304). The temperature of the pressing surface of the upper mold core (306) and the stamping surface of the upper mold core (304) are detected, and the detected temperature is transmitted to the mold temperature controller. The mold temperature controller is used to compare the received temperature with the pre-stored target temperature, and adjust the temperature of the heat transfer oil according to the comparison result. It is also used to deliver the heat transfer oil to the heat transfer oil pipelines of each molding table (307), each first push block heat transfer oil pipeline (308), each second push block heat transfer oil pipeline (309), each third push block (304) heat transfer oil pipeline and each upper mold core heat transfer oil pipeline.

4. The mold tooling for forming multi-flanged thermoplastic composite corner pieces according to claim 1, characterized in that: The first push block (302) is driven to move horizontally in the front-back direction by the first hydraulic rod (3010), the second push block (303) is driven to move horizontally in the left-right direction by the second hydraulic rod (3011), and the third push block (304) is driven to move horizontally in the left-right direction by the third hydraulic rod (3012).

5. The mold tooling for forming multi-flanged thermoplastic composite corner pieces according to claim 1, characterized in that: The upper mold core (306) moves downward into place, and the bottom surface of the upper operating table (305) is in contact with the top surfaces of the first push block (302), the second push block (303), and the third push block (304).

6. A method for molding a multi-flanged thermoplastic composite corner piece, comprising molding using a mold tooling for molding multi-flanged thermoplastic composite corner pieces as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. The thermoplastic composite material sheet blank (2) is heated and softened, wherein the thermoplastic composite material sheet blank (2) is provided with a first bending auxiliary line (201), a second bending auxiliary line (202) and a third bending auxiliary line (203). S2-1. The heated and softened thermoplastic composite material sheet blank (2) is moved above the first push block (302), the second push block (303) and the third push block (304), wherein the first bending auxiliary line (201) is perpendicular to the moving direction of the first push block (302), the second bending auxiliary line (202) is perpendicular to the moving direction of the second push block (303), and the third bending auxiliary line (203) is parallel to the moving direction of the third push block (304). S2-2, Control the first push block (302) to move backward to the first limit position, so that the first bending auxiliary line (201) is in front of the first push block (302), and control the second push block (303) to move left to the second limit position (3013), so that the second bending auxiliary line (202) is in the right side of the second push block (303); S2-3. The upper operating table (305) is controlled by the press to drive the upper mold core (306) to press downward. After the upper mold core (306) is pressed downward, it cooperates with the first push block (302) to make the thermoplastic composite material sheet blank (2) pre-bend along the first bending auxiliary line (201) to pre-form the rear first flange (102), and cooperates with the second push block (303) to make the thermoplastic composite material sheet blank (2) pre-bend along the second bending auxiliary line (202) to pre-form the side flange (104), and cooperates with the forming table (30101) to form the base plate (101). S2-4. Control the first push block (302) to move forward to push the pre-formed rear first flange (102) forward to the upper mold core (306) to form the rear first flange (102), and control the second push block (303) to move to the right to push the pre-formed side flange (104) to the right to the upper mold core (306) to form the side flange (104). S2-5. Control the first push block (302) to move backward to the first limit position while keeping the position of the second push block (303) unchanged, and then control the third push block (304) to move to the right. The third push block (304) cooperates with the second push block (303) and the upper mold core (306) to pre-bend the thermoplastic composite material sheet blank (2) along the third bending auxiliary line (203) to pre-form the rear second flange (103). S2-6. Control the third pusher block (304) to move to the left and reset, and then control the first pusher block (302) to move forward to push the pre-formed rear second flange (103) forward to the upper mold core (306) to form the rear second flange (103) and complete the forming of the multi-flange thermoplastic composite corner piece (1).

7. The molding method for a multi-flanged thermoplastic composite corner piece according to claim 6, characterized in that: The front-to-back horizontal distance between the first limiting position in step S2-2 and the rear first flange (102) formed in step S2-4 is 40mm. The left-to-right horizontal distance between the second limiting position (3013) in step S2-2 and the side flange (104) formed in step S2-4 is 40mm. The pre-bending angle of the pre-formed rear first flange (102) relative to the formed base plate (101) in step S2-3 is 70°-80°. The pre-bending angle of the pre-formed side flange (104) relative to the formed base plate (101) in step S2-3 is 70°-80°.

8. The molding method for a multi-flanged thermoplastic composite corner piece according to claim 6, characterized in that, Before step S1, the following steps are also included: First, select a thermoplastic composite material sheet with continuous carbon fiber reinforced polyether ether ketone and a thickness of 1mm-6mm. Then, cut the thermoplastic composite material sheet according to the size of the formed multi-flanged thermoplastic composite corner piece (1) to obtain a thermoplastic composite material sheet blank (2). Then, fix the cut thermoplastic composite material sheet blank (2) onto a polyimide film. After that, the polyimide film is tensioned by a film tension system, and the two ends of the tensioned imide film are clamped onto the transfer frame by a pneumatic clamp. Step S1 specifically involves transferring the transfer frame to an oven using a robotic arm to heat and soften the thermoplastic composite material sheet blank (2).

9. A method for molding a multi-flanged thermoplastic composite corner piece according to claim 8, characterized in that, In step S1: the oven is an infrared heating furnace, and the heating temperature of the infrared heating furnace is set to 330℃-430℃. The heating rate is set to 30℃ / min-150℃ / min, and the holding time is set to 5s-100s; In step S2-1: After the thermoplastic composite material sheet blank (2) is heated and softened, the polyimide film together with the thermoplastic composite material sheet blank (2) is transferred to the top of the first push block (302), the second push block (303) and the third push block (304) by the transfer frame using a robotic arm; In steps S2-3: After the upper mold core (306) moves downward into place and completes the mold closing of the upper and lower molds, the upper mold core (306) is pressurized by the press at a rate of 50T / s-800T / s and pressurized to the set pressure value of 50KN-800KN to complete the downward punching of the upper mold core (306); In steps S2-4: After the first push block (302) moves forward into position, the first push block (302) is pressurized at a rate of 50T / s-800T / s and pressurized to the set pressure value of 50KN-800KN, and then held for 5s-60s to complete the forming of the rear first flange (102). After the second push block (303) moves to the right into position, the second push block (303) is pressurized at a rate of 50T / s-800T / s and pressurized to the set pressure value of 50KN-800KN, and then held for 5s-60s to complete the forming of the side flange (104). During the forming of the rear first flange (102) and the side flange (104), the upper mold core (306) is held under a pressure value of 50KN-800KN. In steps S2-5: during the pre-forming process of the rear second flange (103), the second push block (303) and the upper mold core (306) are respectively pressure-held under pressure values ​​of 50KN-800KN; In steps S2-6: After the first push block (302) moves forward into place, the first push block (302) is pressurized at a rate of 50T / s-800T / s and pressurized to the set pressure value of 50KN-800KN, and then held for 5s-60s to complete the forming of the rear second flange (103). During the forming of the rear second flange (103), the upper mold core (306) is held under a pressure value of 50KN-800KN.

10. A method for molding a multi-flanged thermoplastic composite corner piece according to claim 9, characterized in that, It also includes step S3: first, the upper operating table (305) is controlled by the press to drive the upper mold core (306) to move upward, and then the formed multi-flanged thermoplastic composite corner piece (1) is removed from the polyimide film and naturally cooled to room temperature; It also includes step S4: cutting, grinding and sealing the edges of the multi-flanged thermoplastic composite corner piece (1) according to the actual size of the formed multi-flanged thermoplastic composite corner piece (1).

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