Adjustable gap forming die

Abstract

This invention discloses an adjustable-gap molding die, relating to the field of prepreg manufacturing technology. Both the upper and lower mold bodies are equipped with die-out adjustment mechanisms on their opposite sides to eject and retract the die opening, compensating for thermal deformation of the die opening. This invention provides an adjustable-gap molding die that, through the die-out adjustment mechanism, ejects or retracts the die opening from or into the mounting groove, thereby actively compensating for thermal deformation of the die opening and maintaining the flatness of the die-out surface and the parallelism between the two die-out surfaces.

Description

Technical Field

[0001] This invention relates to the field of prepreg manufacturing technology, and more particularly to a molding die with adjustable gap. Background Technology

[0002] In the production of thermoplastic prepregs using the slurry method, the thickness accuracy of the prepreg directly affects the performance and quality of the composite material. Currently, the required thickness is typically 0.1 mm to 0.3 mm, with a deviation controlled within ±0.05 mm. This accuracy is mainly ensured by the precise fit of two wedge-shaped dies respectively set on the upper and lower mold bodies. However, because the dies are exposed to high temperatures (above 300°C) for extended periods, they undergo significant thermal deformation, making it difficult to maintain stable flatness of the die surface and parallelism between the two die surfaces.

[0003] To meet the precision requirements at high temperatures, existing technologies typically use elastic materials with low coefficients of thermal expansion to manufacture the die openings, and then perform precision machining and assembly of the die openings in a high-temperature environment to compensate for the effects of thermal deformation. However, this method places extremely high demands on processing equipment, process environment, and material costs. Especially in the production of wide-width prepregs, the increased die opening size further exacerbates the unevenness of thermal deformation, making precision control even more difficult.

[0004] Therefore, there is an urgent need to develop a wedge mold structure that can overcome problems such as high temperature deformation of the die opening, high die opening processing cost, and difficulty in controlling die opening precision, so as to ensure the uniformity and consistency of the thickness of prepreg products. Summary of the Invention

[0005] The purpose of this invention is to provide an adjustable gap molding die, which uses a die opening adjustment mechanism to push the die opening out of the mounting groove or pull the die opening back into the mounting groove, thereby actively compensating for the thermal deformation of the die opening and maintaining the flatness of the die opening surface and the parallelism between the two die opening surfaces.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is: an adjustable gap molding die, including an upper mold body and a lower mold body arranged in parallel and movable relative to each other. The material discharge side of the upper mold body and the lower mold body are both embedded with a mold orifice through a mounting groove, and the extension direction of the mold orifice is perpendicular to the prepreg conveying direction. The opposite sides of the upper mold body and the lower mold body are provided with a mold orifice adjustment mechanism that can eject and pull back the mold orifice to compensate for the thermal deformation of the mold orifice.

[0007] As a further improvement of the present invention, multiple mold opening adjustment mechanisms are provided on both the upper mold body and the lower mold body, and the multiple mold opening adjustment mechanisms are arranged sequentially along the mold opening extension direction; the mold opening adjustment mechanisms on the upper mold body and the lower mold body are staggered.

[0008] As a further improvement of the present invention, the die opening adjustment mechanism includes an internal screw rod with one end perpendicularly passing through the die body and connected to the die opening, wherein the internal screw rod and the die body are in clearance fit; the other end of the internal screw rod is located outside the die body, and the internal screw rod located outside the die body is threaded with an internal and external threaded tube; an external nut is also threaded on the external side of the internal and external threaded tube, and the external nut is fixedly connected to the die body.

[0009] The internal and external threads on the internal and external threaded tube have the same direction of rotation, and the pitch difference between the internal and external threads on the internal and external threaded tube is 0.1mm; the end of the internal and external threaded tube away from the mold body is also provided with a drive component for driving the internal and external threaded tube to rotate axially and for allowing the internal and external threaded tube to move axially.

[0010] As a further improvement of the present invention, the inner and outer threaded tube is coaxially provided with an inner spring at both ends that abut against the inner wall of the inner and outer threaded tube and the end of the inner screw, respectively; the inner and outer threaded tube is provided with an outer spring at both ends that abut against the outer wall of the inner and outer threaded tube and the end of the outer nut, respectively.

[0011] As a further improvement of the present invention, the drive assembly includes a motor, the output end of which is connected to a drive worm gear that can rotate axially, and the drive worm gear is connected to a worm wheel that can rotate axially; it also includes a transmission rod coaxially connected to an internally and externally threaded tube, the outer wall of which is provided with multiple keyways vertically arranged symmetrically around its axis, and the keyways are connected to the worm wheel via keyways.

[0012] As a further improvement of the present invention, the motor, drive worm, worm wheel and part of the transmission rod are provided with an outer shell, and the outer shell is fixedly mounted on a mounting plate, which is fixedly connected to the mold body through a connecting rod.

[0013] As a further improvement of the present invention, the pitch of the internal thread on the internally and externally threaded tube is 2.6 mm, and the pitch of the external thread is 2.5 mm.

[0014] As a further improvement of the present invention, it also includes a frame, wherein the upper mold body is horizontally fixed on the upper part of the frame, the lower mold body is horizontally disposed below the upper mold body, and the frame below the lower mold body is provided with a lifting mechanism for driving the lower mold body to rise and fall.

[0015] As a further improvement of the present invention, the frame is also provided with a guide mechanism for guiding the lifting path of the lower mold body; the guide mechanism includes a slider fixedly disposed on the outer side wall of the lower mold body, and a guide rod that slides through the slider and slides with it. The upper end and the lower end of the guide rod are both fixedly connected to the frame through a fixed seat.

[0016] As a further improvement of the present invention, the lifting mechanism is a worm gear lift, and the upper end of the output rod of the worm gear lift is connected to the lower surface of the lower mold body.

[0017] Beneficial effects

[0018] Compared with the prior art, the advantages of the adjustable gap molding die of the present invention are as follows:

[0019] 1. Active thermal deformation compensation capability: By setting independent die opening adjustment mechanisms in both the upper and lower mold bodies, it can perform online and active precise compensation for deformations such as die opening bending and warping caused by high temperature during the production process, effectively overcoming the problem of precision loss caused by die opening thermal deformation in traditional molds.

[0020] 2. Extremely high adjustment precision: The die adjustment mechanism, employing the differential screw principle, converts the macroscopic rotational motion of the thread into micron-level axial displacement. Calculations show that it can achieve an adjustment of 0.1mm per revolution, or even 0.027 microns per degree, fully meeting the stringent tolerance requirements of ±0.05mm for prepreg thickness;

[0021] 3. High rigidity and anti-lock-up design: The use of large-diameter, large-pitch threaded parts ensures sufficient force transmission while reducing machining difficulty. Simultaneously, the double-spring preload structure not only eliminates backlash in the threaded pair but also compensates for changes in thread fit caused by temperature differences, effectively preventing thread lock-up at high temperatures and improving the reliability and lifespan of the mechanism.

[0022] 4. Zonal control and global flatness guarantee: Multiple die adjustment mechanisms staggered along the width direction form a dense network of action points, allowing operators to make "local micro-carving" adjustments to the die gap based on the measured thickness data, ensuring the consistency of thickness throughout the width direction of the prepreg.

[0023] 5. Significantly reduced costs: This invention reduces the dependence on the die base material (no need to use materials with ultra-low coefficient of expansion) and extreme processing environments (no need for precision machining at high temperatures). By compensating for processing and thermal deformation errors through an adjustable mechanism, it significantly reduces the manufacturing cost and maintenance difficulty of the mold while ensuring higher precision.

[0024] The invention will become clearer from the following description, taken in conjunction with the accompanying drawings, which are used to explain embodiments of the invention. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0027] Figure 2 This is a schematic diagram of the internal structure of the present invention;

[0028] Figure 3 This is a schematic diagram of the structure of the driving component of the present invention.

[0029] Wherein: 1-Frame; 2-Upper mold body; 21-Mold opening; 211-Mold opening mounting slot; 3-Lower mold body; 4-Guide rod; 41-Fixed seat; 42-Slider; 5-Worm gear jack; 6-Mounting plate; 61-Connecting rod; 7-Drive worm; 71-Worm wheel; 72-Motor; 73-Outer shell; 8-Internal and external threaded tube; 81-Internal thread; 82-External nut; 83-Internal spring; 84-External spring; 85-Transmission rod; 851-Keyway; 9-Limit block. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0031] 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; of course, they can also refer to a mechanical connection or an electrical connection; furthermore, they can refer to a direct connection, an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0032] Embodiments of the present invention will now be described with reference to the accompanying drawings.

[0033] Example:

[0034] Specific embodiments of the present invention are as follows: Figure 1-3As shown, an adjustable gap molding die mainly consists of a frame 1, an upper mold body 2, a lower mold body 3, a guiding mechanism, a lifting mechanism, and a core mold opening adjustment mechanism.

[0035] The frame 1 serves as the supporting structure for the entire mold. The upper mold body 2 is horizontally fixed to the upper part of the frame 1 by bolts or other connection methods. The lower mold body 3 is arranged parallel to the lower mold body 2 below, and the frame 1 below the lower mold body 3 is equipped with a lifting mechanism for driving the lower mold body 3 to rise and fall. The lifting mechanism is preferably a worm gear lift 5, whose body is fixed to the frame 1, and the upper end of the output rod is connected to the lower surface of the lower mold body 3. By driving the worm gear lift 5, the lower mold body 3 can be smoothly raised or lowered as a whole, realizing the mold closing and opening with the upper mold body 2. To ensure that the lower mold body 3 does not wobble during the lifting process, a guide mechanism is provided to guide the lifting path of the lower mold body 3. The guiding mechanism includes a guide rod 4 that is vertically fixed to the frame 1 via a fixed seat 41. The upper and lower ends of the guide rod 4 are both fixedly connected to the frame 1 via the fixed seat 41. It also includes a slider 42 fixed to the outer wall of the lower mold body 3. The slider 42 and the guide rod 4 slide through each other to form a sliding pair, which accurately guides the lifting path of the lower mold body 3.

[0036] The core innovation of this device lies in the design of the die opening 21 and the die opening adjustment mechanism. Mounting grooves 211 are provided on the opposite discharge sides of both the upper die body 2 and the lower die body 3, and the die opening 21 is embedded in these grooves. The extension directions of the two die openings 21 are perpendicular to the conveying direction of the prepreg, and the gap between them together form a wedge-shaped die opening that determines the thickness of the prepreg.

[0037] To actively compensate for thermal deformation of the die opening 21 under high-temperature (above 300℃) conditions, die opening adjustment mechanisms are provided on the opposite sides of both the upper die body 2 and the lower die body 3. Multiple die opening adjustment mechanisms are provided on both the upper die body 2 and the lower die body 3, arranged sequentially along the extension direction of the die opening 21 (i.e., the width direction of the prepreg). A preferred embodiment is that the die opening adjustment mechanisms on the upper die body 2 and the lower die body 3 are staggered in the vertical direction, thus forming a denser network of adjustment points and achieving more precise local deformation compensation for the die opening 21 surface.

[0038] The specific components of each die opening adjustment mechanism are as follows:

[0039] It includes an internal threaded rod 81, one end of which passes vertically through the mold body (upper mold body 2 or lower mold body 3) and is fixed or abuts against the back of the mold opening 21. The hole between the internal threaded rod 81 and the mold body is a clearance fit, allowing axial movement of the internal threaded rod 81. The other end of the internal threaded rod 81 is located outside the mold body. A threaded tube 8 is threadedly connected to the rod body portion of the internal threaded rod 81 located outside the mold body via its internal thread. An external nut 82 is threadedly connected to the external thread of the threaded tube 8 via its internal thread, and the external nut 82 is fixedly connected to the mold body by means of threads or flanges.

[0040] The internal and external threads on the internally and externally threaded tube 8 have the same direction of rotation, but their pitches differ slightly. As a specific, non-limiting embodiment, the pitch of the internal thread on the internally and externally threaded tube 8 is 2.6 mm, and the pitch of the external thread is 2.5 mm, with a pitch difference of 0.1 mm. According to the differential screw principle, when the internally and externally threaded tube 8 rotates, since the external nut 82 is fixed, the axial displacement of the internally and externally threaded tube 8 relative to the external nut 82 (i.e., the mold body) is 2.5 mm for each rotation, while the axial displacement of the internal screw 81 relative to the internally and externally threaded tube 8 is 2.6 mm. Therefore, the actual net displacement of the internal screw 81 (together with the mold opening 21) relative to the mold body is 2.6 mm - 2.5 mm = 0.1 mm. The adjustment amount for one rotation is 0.1 mm, that is, the adjustment amount for every 1° rotation is approximately 0.027 micrometers, achieving micrometer-level precise adjustment.

[0041] To eliminate backlash in the threaded drive and ensure adjustment accuracy and responsiveness, a double-spring preload structure is implemented. An inner spring 83 is coaxially mounted inside the internally and externally threaded tube 8, with its two ends abutting against the inner wall of the tube 8 and the end of the inner screw 81, respectively. An outer spring 84 is coaxially sleeved outside the internally and externally threaded tube 8, with its two ends abutting against the outer wall of the tube 8 and the end of the outer nut 82, respectively. The inner spring 83 and outer spring 84 work together to provide continuous axial preload to the entire threaded pair system, forcing all threaded contact surfaces to remain on one side at all times. This effectively reduces backlash and compensates for potential fit changes due to differences in the thermal expansion coefficients of the materials at high temperatures, preventing thread lock-up.

[0042] The die adjustment mechanism also includes a drive assembly located at the end of the internally and externally threaded tube 8 furthest from the die body, for driving the internally and externally threaded tube 8 to rotate and allowing its axial movement. This drive assembly includes a motor 72 (such as a servo motor), a drive worm 7, a worm wheel 71, and a transmission rod 85. The motor 72 is fixedly mounted, and its output shaft is connected to the drive worm 7. The drive worm 7 meshes with the worm wheel 71. The transmission rod 85 is coaxially connected to the internally and externally threaded tube 8. Several (e.g., four) vertical keyways 851 are machined on the outer wall of the transmission rod 85, arranged symmetrically around its axis. The worm wheel 71 engages with these keyways 851 via a key, thereby transmitting rotational motion to the transmission rod 85 and the internally and externally threaded tube 8, while simultaneously allowing the transmission rod 85 and the internally and externally threaded tube 8 to move axially relative to the worm wheel 71. To protect the transmission components, the motor 72, drive worm 7, worm wheel 71 and part of the transmission rod 85 are encapsulated in a housing 73, which is fixed to a mounting plate 6. The mounting plate 6 is fixedly connected to the mold body through a connecting rod 61.

[0043] The specific working process of this device is as follows:

[0044] Initially, the lower mold body 3 is raised by the worm gear jack 5 until the limiting block 9 on the edge of the lower mold body 3 abuts against the upper mold body 2, at which point a basic gap is formed between the mold openings 21. During production, the mold is heated to the working temperature (above 300℃), and the mold openings 21 will deform unevenly due to the heat, resulting in deviations in the thickness of the prepreg.

[0045] Based on feedback from the online thickness gauge, the operator can activate the motor 72 of the corresponding die opening adjustment mechanism. The motor 72 drives the worm wheel 71 to rotate via the worm 7, and the worm wheel 71 drives the transmission rod 85 and the internally and externally threaded tube 8 to rotate via the keyway 851. According to the differential screw principle, the rotation of the internally and externally threaded tube 8 will be converted into a slight axial movement of the internal screw 81 relative to the die body, thereby pushing the die opening 21 out of the mounting groove 211 or pulling it back into the groove, accurately correcting the die opening gap in this local area.

[0046] This invention achieves active thermal deformation compensation and micron-level precision adjustment through the above design. The dual-spring preload mechanism ensures high rigidity and anti-lock-up performance at high temperatures. Multiple staggered adjustment mechanisms enable zoned control, ensuring overall flatness. Ultimately, this solution reduces dependence on materials and extreme processing techniques, significantly lowering costs while ensuring high uniformity and consistency in the thickness of the prepreg product.

[0047] The present invention has been described above in conjunction with the preferred embodiments, but the present invention is not limited to the embodiments disclosed above, but should cover various modifications and equivalent combinations made in accordance with the essence of the present invention.

Claims

1. An adjustable gap forming die comprising an upper die body (2) and a lower die body (3) arranged in parallel and capable of relative movement, the opposite sides of the upper die body (2) and the lower die body (3) are both embeddedly installed with a die orifice (21) through a mounting groove (211), and the extension direction of the die orifice (21) is perpendicular to the pre-preg conveying direction, characterized in that, Both the upper mold body (2) and the lower mold body (3) are provided with a mold opening adjustment mechanism that can eject and pull back the mold opening (21) to compensate for the thermal deformation of the mold opening (21); Multiple die opening adjustment mechanisms are provided on both the upper mold body (2) and the lower mold body (3), and the multiple die opening adjustment mechanisms are arranged sequentially along the extension direction of the die opening (21); the die opening adjustment mechanisms on the upper mold body (2) and the lower mold body (3) are staggered. The die opening adjustment mechanism includes an inner screw (81) with one end perpendicularly passing through the die body and connected to the die opening (21). The inner screw (81) and the die body are in clearance fit. The other end of the inner screw (81) is located outside the die body, and the inner screw (81) located outside the die body is threaded with an inner and outer threaded tube (8). The inner and outer threaded tube (8) is also threaded with an outer nut (82), and the outer nut (82) is fixedly connected to the die body. The internal and external threads on the internal and external threaded tube (8) have the same direction of rotation, and the pitch difference between the internal and external threads on the internal and external threaded tube (8) is 0.1 mm; the end of the internal and external threaded tube (8) away from the mold body is also provided with a drive assembly for driving the internal and external threaded tube (8) to rotate axially and for allowing the internal and external threaded tube (8) to move axially. The inner and outer threaded tube (8) is coaxially provided with an inner spring (83) whose two ends are respectively in close contact with the inner wall of the inner and outer threaded tube (8) and the end of the inner screw (81); the inner and outer threaded tube (8) is provided with an outer spring (84) whose two ends are respectively in close contact with the outer wall of the inner and outer threaded tube (8) and the end of the outer nut (82). The drive assembly includes a motor (72), the output end of which is connected to a drive worm (7) that can rotate axially, and the drive worm (7) is connected to a worm wheel (71) that can rotate axially; it also includes a transmission rod (85) coaxially connected to the internal and external threaded tube (8), and the outer wall of the transmission rod (85) is provided with multiple keyways (851) arranged vertically around its axis and symmetrically arranged, and the keyways (851) are connected to the worm wheel (71) by keyway transmission. It also includes a frame (1), the upper mold body (2) is horizontally fixed on the upper part of the frame (1), the lower mold body (3) is horizontally arranged below the upper mold body (2), and the frame (1) below the lower mold body (3) is provided with a lifting mechanism for driving the lower mold body (3) to rise and fall.

2. The adjustable gap molding die according to claim 1, characterized in that, The motor (72), drive worm (7), worm wheel (71) and part of the transmission rod (85) are provided with an outer shell (73), and the outer shell (73) is fixed on a mounting plate (6). The mounting plate (6) is fixedly connected to the mold body through a connecting rod (61).

3. The adjustable gap molding die according to claim 1, characterized in that, The pitch of the internal thread on the internally and externally threaded pipe (8) is 2.6 mm, and the pitch of the external thread is 2.5 mm.

4. The adjustable gap molding die according to claim 1, characterized in that, The frame (1) is also provided with a guide mechanism for guiding the lower mold body (3) to rise and fall. The guide mechanism includes a slider (42) fixedly installed on the outer side wall of the lower mold body (3). A guide rod (4) is vertically installed on the slider (42) and slides through it. The upper and lower ends of the guide rod (4) are fixedly connected to the frame (1) through a fixed seat (41).

5. The adjustable gap molding die according to claim 1 or 4, characterized in that, The lifting mechanism is a worm gear lift (5), and the upper end of the output rod of the worm gear lift (5) is connected to the lower surface of the lower mold body (3).

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