Tension-adjustable impregnation mold and impregnation method

Abstract

The present invention relates to the technical field of composite material molding, and more specifically, to a tension-adjustable impregnation mold and impregnation method, wherein the mold cavity includes a plurality of cavities connected end to end, each cavity is provided with an impregnation roller that can rotate to adjust the fiber tension, and each cavity is connected to a melt feed port for feeding resin melt. The fiber enters from the fiber feed port, bypasses the periphery of each impregnation roller, is impregnated with the resin melt in the cavity, and then is discharged from the discharge port; the impregnation method is a method for manufacturing an impregnated product using the above-mentioned impregnation mold. The tension of the fiber in each cavity of the present invention is adjustable, so as to avoid too little tension, too little contact area between the fiber and the resin melt, and poor impregnation effect, and to avoid excessive tension causing fiber breakage; in addition, each cavity is provided with a melt feed port, and the resin melt is fed from different positions. The fiber is repeatedly impregnated with the fiber in multiple stages to achieve better coating of the fiber with the resin melt, thereby obtaining a better impregnation effect.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material molding, and more particularly to a tension-adjustable impregnation mold and an impregnation method. Background Art

[0002] Long-fiber-reinforced thermoplastic composites (LFT) and prepreg composite tapes, for example, are highly valued in the automotive lightweighting sector due to their excellent mechanical properties and cost-effectiveness. Their lightweight, high-strength properties help ensure the long driving range of energy vehicles, and they are widely used in parts such as battery covers, power battery underbody panels, instrument panel frames, and door panels. Currently, LFT production primarily relies on pultrusion, and the fiber impregnation process is significantly affected by the equipment. This often results in uneven fiber impregnation, manifested by particle bursting and excessive free fiber hairiness.

[0003] Chinese patent CN106903906A discloses a continuous fiber reinforced thermoplastic resin melt impregnation mold and preparation method, which consists of a dispersion roller and a slit roller. The slit roller is rotatable, so the coating angle of the fiber bundle melt impregnation can be changed by rotating the slit roller, and the tension of the fiber bundle in the mold can be changed; by combining the dispersion roller and the slit roller, the fibers are fully dispersed and fully impregnated through the slit flow channel. Although the above scheme can adjust the tension of the fiber bundle by rotating the slit roller, the above scheme only feeds through one feed port. In locations with greater tension, if faster concentrated feeding is used, uneven impregnation may occur, affecting the impregnation effect of the product; in addition, using faster concentrated feeding will also produce concentrated melt resistance on the fibers, which is prone to fiber breakage and affecting production efficiency. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide an impregnation mold and impregnation method with adjustable tension, which can not only adjust the fiber tension, but also adjust the feeding flow rate of the resin melt in different areas according to the tension, thereby effectively improving the product impregnation effect.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A tension-adjustable impregnation mold is provided, comprising an upper mold plate, a lower mold plate, and a mold cavity formed around the upper mold plate and the lower mold plate, wherein a fiber feed port and a discharge port are respectively provided at both ends of the mold cavity, and the mold cavity comprises a plurality of cavities connected end to end in sequence, wherein each cavity is provided with an impregnation roller that can be rotated to adjust the fiber tension, and each cavity is connected to a melt feed port for feeding a resin melt, wherein the fiber enters from the fiber feed port, bypasses the outer periphery of each impregnation roller, is impregnated with the resin melt in the cavity, and then is discharged from the discharge port.

[0007] The tension-adjustable impregnation die of the present invention comprises fibers entering through a fiber feed port, passing around the periphery of each impregnation roller, and being impregnated with a resin melt within the cavity before exiting through a discharge port. The resin melt is fed into the cavity through the melt feed port and impregnates the fibers within the cavity, making the die suitable for preparing fiber-reinforced resin composite materials. In the present invention, the impregnation rollers within each cavity can be rotated to adjust the tension applied to the fibers within the cavity, thereby preventing excessive tension from causing a small contact area between the fibers and the resin melt, resulting in poor impregnation, and also preventing excessive tension from causing fiber breakage. Furthermore, in the present invention, each cavity is provided with a melt feed port, allowing the resin melt to be fed from different locations. Multiple feeding stages allow for repeated impregnation of the fibers, resulting in better coating of the fibers with the resin melt and a better impregnation effect.

[0008] Furthermore, the tension exerted on the fiber by the impregnation roller in the first cavity and the tension exerted on the fiber by the impregnation roller in the last cavity are less than the tension exerted on the fiber by any impregnation roller in the middle position; the feed flow rate of the melt feed port of the first cavity and the feed flow rate of the melt feed port of the last cavity are greater than the feed flow rate of the melt feed port of any cavity in the middle position. By setting the tension in a sequence of small, large, and small, the fiber is not easily broken under the action of small tension when entering the mold. After passing through a cavity, when the surface temperature of the fiber rises to a temperature that makes it easier to impregnate with the resin melt, the tension is increased to improve the impregnation effect; finally, the end cavity stably impregnates the fiber bundle with small tension, and finally obtains a stably impregnated material strip; according to the principle of large tension and small feed, when the fiber tension in the first and last cavities is relatively small, a relatively large feed flow rate is set to help the resin melt fully cover the fiber surface; and when the fiber tension in the middle cavity is large, a correspondingly small feed flow rate is set to avoid concentrated melt resistance leading to fiber breakage.

[0009] Furthermore, the tension exerted on the fibers by the impregnation roller in the first cavity is no greater than that exerted on the fibers by the impregnation roller in the last cavity, and the feed rate at the melt inlet of the first cavity is no less than that of the melt inlet of the last cavity. This reduces the tension on the fibers entering the mold in the first cavity, making them less susceptible to breakage. In the last cavity, since the fibers have already been partially impregnated with the resin melt in the cavity before the last, a smaller feed rate can be used in the last cavity to achieve uniform impregnation.

[0010] Furthermore, the number of the cavities is 2N-1, where N≥2 and N is a positive integer; the tension exerted on the fiber by the impregnation roller in each cavity is recorded as F1, F2...F N 、F N+1 ...F 2N-1 , then, F1 <F2<F3<……<F N , F 2N-1 <F 2N-2 <F 2N-3 <…… <FN The feeding flow in each cavity is recorded as Q1, Q2...Q N , Q N+1 ...Q 2N-1 , then, Q1>Q2>Q3>……>Q N , Q 2N-1 >Q 2N-2 >Q 2N-3 >……>Q N From the first cavity to the last cavity, the tension first increases gradually and then decreases gradually, and the feeding flow rate first decreases gradually and then increases gradually. The tension and feeding flow rate both change gradually, and the changing trends of the tension and feeding flow rate are opposite. The two factors cooperate with each other to obtain a better impregnation effect.

[0011] Furthermore, the upper template is provided with multiple first corrugated surfaces, and the lower template is provided with multiple second corrugated surfaces arranged symmetrically with the first corrugated surfaces. The cavity is formed between the first and second corrugated surfaces. The minimum distance between the first and second corrugated surfaces is D1, and the maximum distance between the first and second corrugated surfaces is D2. Along the direction from the fiber feed port to the discharge port, the distance between the first and second corrugated surfaces gradually increases from D1 to D2, and then gradually decreases from D2 to D1. This arc-shaped cavity allows the continuously accumulated resin melt fed from the melt feed port to flow along the arc surface toward both ends, increasing the area for fiber impregnation and improving the impregnation effect.

[0012] Furthermore, the impregnation roller is an elliptical roller, the center of which coincides with the center of the cavity, the minor axis diameter of the elliptical roller is greater than the minimum distance between the first corrugated surface and the second corrugated surface, and the major axis diameter of the elliptical roller is less than the maximum distance between the first corrugated surface and the second corrugated surface. Within the mold cavity, the fibers interlace around the lower end surface of the first corrugated surface and the upper surface of the elliptical roller, or interlace around the upper end surface of the second corrugated surface and the lower surface of the elliptical roller. The rotation of the elliptical roller is utilized to change the impregnation angle of the fibers to adjust the tension applied to the fibers. The fiber bundle is mainly divided into two parts, one part interlaces around the lower end surface of the first corrugated surface and the upper surface of the elliptical roller, and the other part interlaces around the upper end surface of the second corrugated surface and the lower surface of the elliptical roller. The fibers do not interlace with each other, thereby helping to improve the impregnation effect.

[0013] Furthermore, two sets of melt feed ports are connected to the same cavity, with the axes of the two melt feed ports in the same cavity coinciding, passing through the center of the cavity, and perpendicular to the axis of the fiber feed port. Analyzing the impregnation process using the top melt feed port as an example, a portion of the resin melt flowing in from the top flows onto the fiber surface, while a portion is carried by the fiber to the next cavity for impregnation, maximizing the contact area between the melt and the fiber. Another portion of the resin melt passes through the fiber surface and falls through the gap to the other fiber surface, further impregnating the lower fibers.

[0014] Furthermore, the invention further comprises side guards connected to the upper and lower templates, and the two ends of the dipping roller are rotatably connected to the side guards via a rotating shaft, and the rotating shaft is connected to a drive motor. The drive motor can be a drive motor with a button, and the dipping angle of the dipping roller can be adjusted by pressing the button.

[0015] Furthermore, the system includes a controller, a flow valve module at the melt inlet, and an identification module for identifying the product surface morphology at the discharge port. The identification module is connected to the controller's input, and the drive motor and flow valve module are both connected to the controller's output. The identification module identifies the product surface morphology and, for products with problems such as side whitening, pelletizing cracks, or excessively large glass fiber fibers, adjusts the tension and feed rate to improve the impregnation effect, thereby achieving real-time tension adjustment.

[0016] The present invention also provides an impregnation method, comprising the following steps:

[0017] S10 pulling the fiber so that the fiber enters from the fiber feed port, bypasses the periphery of each impregnating roller, and is led out from the discharge port;

[0018] S20. Feeding a resin melt into each cavity from each melt feed port, the resin melt enters the cavity and impregnates the fiber in the cavity;

[0019] S30 observes the product morphology of the composite material at the discharge port. If the product surface has a poor morphology, the process proceeds to step S40;

[0020] S40. Rotate the impregnation roller to adjust the tension on the fibers in each cavity: First, adjust the impregnation roller in the middle position to increase the tension on the fibers in the middle position, and observe the composite product morphology at the discharge port; if the product morphology is acceptable, the adjustment is completed; if the product surface still has undesirable morphology, gradually increase the tension on the fibers from the middle position toward the ends, and observe the composite product morphology at the discharge port until the surface has no undesirable morphology, and then the tension adjustment is completed;

[0021] S50. Adjust the tension of the fibers in each cavity obtained in step S40 to continuously produce fiber-reinforced resin composite materials.

[0022] The impregnation method of the present invention adjusts the tension of the fibers in each cavity when the product exhibits undesirable morphologies such as white leakage, pelletizing, and fiber burrs, gradually increasing the tension of the fibers in each cavity from the middle to the ends, and observing the adjusted product morphology in real time. In the present invention, the tension of the fibers in each cavity can be adjusted, effectively avoiding excessive tension, which results in too small a contact area between the fibers and the resin melt, leading to poor impregnation, and also avoiding excessive tension, which results in fiber breakage. In addition, the resin melt is fed from melt feed ports at different locations, and the fibers are repeatedly impregnated in multiple stages to achieve better coating of the fibers with the resin melt, thereby achieving a better impregnation effect.

[0023] Preferably, step S40 further includes the step of synchronously adjusting the feed flow rate of each melt feed port: first, adjust the middle position cavity to reduce the feed flow rate of the middle position cavity, and observe the product morphology of the composite material at the discharge port; if the product morphology is qualified, then end the adjustment; if there is still a bad morphology on the product surface, then gradually reduce the feed flow rate of the cavity from the middle position to both ends, observe the product morphology of the composite material at the discharge port, until there is no bad morphology on the surface, then end the adjustment of the feed flow rate. In the present invention, the synchronous adjustment can be adjusted after each adjustment of the tension on the fibers in each cavity, or it can be adjusted gradually from the middle to both ends when there is still a bad morphology after adjusting the tension on the fibers in all cavities.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The tension-adjustable impregnation mold and impregnation method of the present invention are capable of adjusting the tension on the fibers in each cavity, thereby avoiding the situation where the tension is too low, the contact area between the fibers and the resin melt is too small, and the impregnation effect is poor, while also avoiding the situation where the tension is too high and the fibers break. In addition, each cavity is provided with a melt feed port, and the resin melt is fed from different positions. The fibers are repeatedly impregnated by feeding in multiple stages to achieve better coating of the fibers by the resin melt, thereby obtaining a better impregnation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the structure of the dipping mold with adjustable tension in Example 1;

[0027] Figure 2 This is a schematic structural diagram of the tension-adjustable dipping mold in Example 2;

[0028] Figure 3 Schematic diagram of the installation of the dipping roller of the dipping mold with adjustable tension in Example 3;

[0029] Figure 4 This is a control principle diagram of the controller in Example 3;

[0030] In the accompanying drawings: 1. Upper template; 2. Lower template; 3. Fiber feed port; 4. Discharge port; 5. Cavity; 6. Impregnation roller; 7. Melt feed port; 8. First corrugated surface; 9. Second corrugated surface; 10. Side stop; 11. Rotating shaft; 12. Identification module; 13. Controller; 14. Drive motor. DETAILED DESCRIPTION

[0031] The present invention is further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only and are schematic, not actual, representations. They should not be construed as limiting this patent. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted from the drawings.

[0032] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0033] Example 1

[0034] like Figure 1 The figure shows a first embodiment of a tension-adjustable impregnation mold of the present invention, which is used to prepare fiber-reinforced resin composite materials. The impregnation mold of this embodiment includes an upper mold plate 1, a lower mold plate 2, and a mold cavity formed around the upper mold plate 1 and the lower mold plate 2. A fiber feed port 3 and a discharge port 4 are respectively provided at both ends of the mold cavity. The mold cavity includes a plurality of cavities 5 connected in end-to-end sequence. Each cavity 5 is provided with an impregnation roller 6 that can be rotated to adjust the fiber tension. Each cavity 5 is connected to a melt feed port 7 for feeding resin melt. The fiber enters from the fiber feed port 3, bypasses the outer periphery of each impregnation roller 6, and is impregnated with the resin melt in the cavity 5 before being discharged from the discharge port 4.

[0035] The fibers are pulled by a pulling device, such that they enter the fiber feed port 3, pass around the periphery of each impregnation roller 6, and exit from the discharge port 4. The pulling device provides power for the movement of the fibers. The fibers can pass around the impregnation rollers 6 by passing around the upper surface, the lower surface, or alternately around the upper and lower surfaces of each impregnation roller 6. When the fibers pass around the upper surface or the lower surface of each impregnation roller 6, a tensioning roller is required to tension the fibers. The impregnation roller 6 can be an elliptical roller, an eccentric roller, or a shaped roller, such that the distance between the center point of the impregnation roller 6 and the contact point between the fiber and the impregnation roller 6 changes during rotation. The greater the distance between the center point of the impregnation roller 6 and the contact point between the fiber and the impregnation roller 6, the greater the tension, while the smaller the distance between the center point of the impregnation roller 6 and the contact point between the fiber and the impregnation roller 6, the lower the tension. The fibers can be glass fibers, carbon fibers, or the like, and the resin can be a thermoplastic resin.

[0036] During the implementation of this embodiment, fibers enter through the fiber feed port 3, pass around the periphery of the impregnation rollers 6, and are impregnated with the resin melt within the cavity 5 before exiting through the discharge port 4. The resin melt is fed into the cavity 5 through the melt feed port 7, where it impregnates the fibers, thereby producing a composite material product. The greater the tension, the more dispersed the fiber bundles are into filaments, the greater the contact area with the resin melt, and the better the impregnation effect. However, excessive tension increases the resistance to fiber passage through the impregnation die, making the fibers more susceptible to breakage. The agglomeration of broken fibers creates even greater resistance to fiber passage within the die, ultimately leading to fiber breakage and preventing continuous production. When this embodiment is implemented, the impregnation roller 6 in each cavity 5 can be rotated to adjust the tension on the fiber in the cavity 5, so as to avoid too little tension, too little contact area between the fiber and the resin melt, and poor impregnation effect, and at the same time avoid excessive tension causing fiber breakage; in addition, in the present invention, each cavity 5 is provided with a melt feed port 7, and the resin melt is fed from different positions, and the fiber is repeatedly impregnated by multi-stage feeding to achieve better coating of the fiber by the resin melt and obtain a better impregnation effect.

[0037] Specifically, the tension exerted on the fiber by the dipping roller 6 in the first cavity 5 and the tension exerted on the fiber by the dipping roller 6 in the last cavity 5 is less than the tension exerted on the fiber by any dipping roller 6 in the middle position; the feed rate of the melt feed port 7 in the first cavity 5 and the feed rate of the melt feed port 7 in the last cavity 5 is greater than the feed rate of the melt feed port 7 in any middle position. In this embodiment, except for the first and last positions, the remaining positions are referred to as middle positions. When this embodiment is implemented, the tension is set in the order of small, large, and small, so that the fiber is not easy to break under the action of small tension when entering the mold. After passing through a cavity 5, the surface temperature of the fiber rises to a temperature that makes it easier to impregnate with the resin melt, and the tension is increased to improve the impregnation effect; finally, the end cavity 5 stably impregnates the fiber bundle with small tension, and finally a stably impregnated material strip is obtained; in addition, according to the principle of large tension and small feeding, when the fiber tension in the first cavity 5 and the last cavity 5 is relatively small, a relatively large feeding flow rate is set to help the resin melt to fully cover the fiber surface; and when the fiber tension in the middle cavity 5 is large, a correspondingly smaller feeding flow rate is set to avoid fiber breakage due to concentrated melt resistance.

[0038] The tension exerted on the fiber by the dipping roller 6 in the first cavity 5 is no greater than the tension exerted on the fiber by the dipping roller 6 in the last cavity 5, and the feed rate of the melt feed port 7 in the first cavity 5 is no less than the feed rate of the melt feed port 7 in the last cavity 5. The fiber in the first cavity 5 has a lower temperature when entering the mold and is less likely to break under small tension. In the last cavity 5, the fiber temperature rises and the tension it can withstand is also greater. Therefore, the tension exerted on the fiber by the dipping roller 6 in the last cavity 5 can be greater than the tension exerted on the fiber by the dipping roller 6 in the first cavity 5. In the last cavity 5, since the fiber has already been partially impregnated with the resin melt in the cavity 5 before the last cavity 5, a smaller feed rate in the last cavity 5 can achieve uniform impregnation.

[0039] In addition, the number of cavities 5 is 2N-1, where N≥2 and N is a positive integer; the tension exerted on the fiber by the dipping roller in each cavity is recorded as F1, F2...F N 、F N+1 ...F 2N-1 , then, F1 <F2<F3<……<F N , F 2N-1 <F 2N-2 <F 2N-3 <…… <F N The feeding flow in each cavity is recorded as Q1, Q2...Q N , Q N+1 ...Q 2N-1 , then, Q1>Q2>Q3>……>Q N , Q 2N-1 >Q 2N-2 >Q 2N-3 >……>QN From the first cavity 5 to the last cavity 5, the tension first gradually increases and then gradually decreases, and the feeding flow first gradually decreases and then gradually increases. The tension and feeding flow both change gradually, and the changing trends of the tension and feeding flow are opposite. The two factors cooperate with each other to obtain a better impregnation effect.

[0040] Example 2

[0041] like Figure 2 The figure shows a first embodiment of a tension-adjustable impregnation mold according to the present invention. The upper template 1 is provided with multiple first corrugated surfaces 8, and the lower template 2 is provided with multiple second corrugated surfaces 9 symmetrically arranged with the first corrugated surfaces 8. The cavity 5 is formed between the first corrugated surfaces 8 and the second corrugated surfaces 9. The minimum distance between the first corrugated surfaces 8 and the second corrugated surfaces 9 is D1, and the maximum distance between the first corrugated surfaces 8 and the second corrugated surfaces 9 is D2. Along the direction from the fiber feed port 3 to the discharge port 4, the distance between the first corrugated surfaces 8 and the second corrugated surfaces 9 gradually increases from D1 to D2, and then gradually decreases from D2 to D1. When this embodiment is implemented, the cavity 5 is a cavity 5 set with an arc surface, so that the continuously accumulated resin melt fed from the melt feeding port flows along the arc surface to both ends, increasing the area of ​​fiber impregnation and improving the impregnation effect; the fiber feed port 3 is a bell mouth that is large at first and then small, and the discharge port 4 is a bell mouth that is small at first and then large. The fiber enters the fiber feed port 3 through the narrowest part between the first corrugated surface 8 and the second corrugated surface 9. The lower end surface of the first corrugated surface 8 and the upper end surface of the second corrugated surface 9 squeeze the fiber, so that the fiber path changes; the bell mouth at the discharge port 4 has a stable buffering effect on the impregnated product, which helps to improve the quality of the impregnated product.

[0042] The impregnation roller 6 is an elliptical roller, the center of which coincides with the center of the cavity 5. The minor axis diameter of the elliptical roller is greater than the minimum distance between the first corrugated surface 8 and the second corrugated surface 9, and the major axis diameter of the elliptical roller is less than the maximum distance between the first corrugated surface 8 and the second corrugated surface 9. Within the mold cavity, the fibers intersect and pass around the lower end surface of the first corrugated surface 8 and the upper surface of the elliptical roller, or intersect and pass around the upper end surface of the second corrugated surface 9 and the lower surface of the elliptical roller. In this embodiment, the lower end surface of the first corrugated surface 8 and the upper end surface of the second corrugated surface 9 serve as the tension roller in Example 1. Specifically, when this embodiment is implemented, the rotation of the elliptical roller can change the horizontal passing path of the fiber, thereby realizing the pressure of the first corrugated surface 8, the second corrugated surface 9 and the elliptical roller on the fiber. When the elliptical roller is rotated, the pressure on the fiber can be changed, and the degree of expansion of the monofilaments of the fiber bundle is different, so different impregnation effects can be achieved; in this way, the fiber bundle in this embodiment is divided into two parts: one part is staggered around the lower end surface of the first corrugated surface 8 and the upper surface of the elliptical roller to form a first fiber surface, and the other part is staggered around the upper end surface of the second corrugated surface 9 and the lower surface of the elliptical roller to form a second fiber surface. The fibers in the two fiber surfaces will not be staggered with each other, which can help improve the impregnation effect.

[0043] Since the fiber surface includes a first fiber surface and a second fiber surface, in this embodiment, two groups of melt feed ports 7 are connected to the same cavity 5. The axes of the two melt feed ports 7 in the same cavity 5 coincide with each other, pass through the center of the cavity 5, and are perpendicular to the axis of the fiber feed port 3. The resin melt fed by the multiple melt feed ports 7 at the top partially flows to the first fiber surface, partially is carried by the fiber to the next cavity 5 for impregnation, and partially flows to the rear end area of ​​impregnation, thereby maximizing the contact area between the melt and the fiber. Another part of the resin melt passes through the first fiber surface and falls through the gap to the second fiber surface, thereby impregnating the fibers on the second fiber surface. The resin melt fed by the multiple melt feed ports 7 at the bottom partially flows to the second fiber surface, partially is carried by the fiber to the next cavity 5 for impregnation, and partially flows to the rear end area of ​​impregnation, thereby maximizing the contact area between the melt and the fiber. Another part of the resin melt passes through the second fiber surface and flows through the gap to the first fiber surface, thereby impregnating the fibers on the first fiber surface. This can increase the impregnation area of ​​the fiber by the resin melt and improve the impregnation effect.

[0044] Example 3

[0045] like Figures 3 and 4The third embodiment of the dipping mold with adjustable tension according to the present invention is shown. The mold further includes side guards 10 connected to the upper mold plate 1 and the lower mold plate 2. The ends of the dipping roller 6 are rotatably connected to the side guards 10 via a rotating shaft 11. The rotating shaft 11 is connected to a drive motor 14. The drive motor 14 can be a drive motor 14 with a button. By pressing the button, the dipping angle of the dipping roller 6 can be adjusted. This operation can be adjusted based on the operator's experience.

[0046] In order to achieve real-time adjustment of tension, the impregnation mold of this embodiment also includes a controller 13, a flow valve module is provided at the melt feed port 7, and an identification module 12 for identifying the surface morphology of the product is provided at the discharge port 4. The identification module 12 is connected to the input end of the controller 13, and the drive motor 14 and the flow valve module are both connected to the output end of the controller 13.

[0047] The recognition module 12 identifies the surface morphology of the product. For products with problems such as side whitening, pelletizing explosion, and fiber burrs, the recognition module 12 can specifically use image recognition; if it identifies the presence of undesirable morphologies such as side whitening, pelletizing explosion, and fiber burrs, it transmits a signal to the controller 13. The controller 13 improves the impregnation effect by adjusting the tension and feed rate, thereby achieving real-time adjustment of the tension. However, it should be noted that no matter how the tension and feed rate are adjusted, the following rules must still be met: the tension generated by the impregnation roller 6 on the fiber in each cavity 5 meets the following rules: F1 <F2<F3<……<F N , F 2N-1 <F 2N-2 <F 2N-3 <…… <F N The feeding flow rate in each cavity 5 satisfies the following rules: Q1>Q2>Q3>……>Q N , Q 2N-1 >Q 2N-2 >Q 2N-3 >……>Q N .

[0048] Example 4

[0049] This embodiment is an embodiment of an impregnation method, which is implemented based on the tension-adjustable impregnation mold of any one of the first to third embodiments, and includes the following steps:

[0050] S10 pulling the fiber so that the fiber enters from the fiber feed port 3, bypasses the periphery of each impregnation roller 6, and is led out from the discharge port 4;

[0051] S20. The resin melt is fed into each cavity 5 by each melt feed port 7, the resin melt enters the cavity 5 and impregnates the fiber in the cavity 5;

[0052] S30 observes the product morphology of the composite material at the discharge port 4. If the product surface has an undesirable morphology, the process proceeds to step S40. In this embodiment, undesirable morphologies include white leakage, pelletizing cracks, fiber burrs, and other morphologies. Of course, other undesirable morphologies may also be set according to actual conditions.

[0053] S40. Rotate the impregnating roller 6 to adjust the tension on the fibers in each cavity 5: First, adjust the impregnating roller 6 in the middle position to increase the tension on the fibers in the middle position, and observe the composite product morphology at the discharge port 4; if the product morphology is acceptable, the adjustment is completed; if the product surface still has undesirable morphology, gradually increase the tension on the fibers from the middle position toward the ends, and observe the composite product morphology at the discharge port 4 until the surface has no undesirable morphology, and then the tension adjustment is completed;

[0054] S50. Adjust the tension of the fibers in each cavity 5 obtained in step S40 to continuously produce fiber-reinforced resin composite materials.

[0055] In step S30, the product appearance can be observed by the operator's eyes or by a visual recognition system.

[0056] In step S40, the tension on the fiber is gradually increased from the middle position to both ends. The specific adjustment method is as follows. Take the dipping roller 6 as an odd number (2N-1) dipping roller 6 and the maximum tension of each dipping roller 6 as T as an example: first adjust the tension of the Nth dipping roller 6, adjust the tension of the Nth dipping roller 6 to the maximum, and observe the product morphology; if the product surface has a bad morphology, increase the tension of the two dipping rollers 6 on both sides of the Nth dipping roller 6, that is, increase the tension of the N-1th dipping roller 6 and the N+1th dipping roller 6, such as to 0.9T; observe the product morphology, if the product surface has a bad morphology, increase the tension of the N-2th dipping roller 6 and the N+2th dipping roller 6, such as to 0.8T; adjust in sequence until there is no bad morphology on the product surface. In the process of adjusting the tension of the dipping roller 6, no matter how it is adjusted, the following rules should be met: F1 <F2<F3<……<F N , F 2N-1 <F 2N-2 <F 2N-3 <…… <F N .

[0057] In addition to the tension adjustment, step S40 may also include the step of synchronously adjusting the feeding flow of each melt feed port: first adjust the middle position cavity 5 to reduce the feeding flow of the middle position cavity 5, and observe the product morphology of the composite material at the outlet 4; if the product morphology is qualified, then end the adjustment; if there is still a bad morphology on the product surface, then gradually reduce the feeding flow of the cavity 5 from the middle position to both ends, observe the product morphology of the composite material at the outlet 4, until there is no bad morphology on the surface, then end the adjustment of the feeding flow. The synchronous adjustment in this embodiment can be to adjust the feeding flow of the cavity 5 after each adjustment of the tension on the fibers in each cavity 5, or to gradually adjust the feeding flow of each cavity 5 from the middle to both ends when there is still a bad morphology after adjusting the tension on the fibers in all cavities 5. Specifically:

[0058] In the process of adjusting the tension, the feeding flow of each melt feed port 7 can be adjusted synchronously. However, no matter how the feeding flow is adjusted, the feeding flow in each cavity 5 should meet the following rules: Q1>Q2>Q3>……>Q N , Q 2N-1 >Q 2N-2 >Q 2N-3 >……>Q N , meeting the principle of high tension and low feed rate. For example, when increasing the tension of a certain dipping roller 6, the feed rate of that cavity 5 can be reduced until the composite material surface at the outlet 4 meets the required morphology. If, after adjusting the tension of each dipping roller 6 to its upper limit, the product surface still exhibits undesirable morphology, consider increasing the feed rate of each melt feed port 7 appropriately, for example by 5%, as long as the adjusted tension and feed rate still meet the above requirements.

[0059] If the fiber tension in all cavities is adjusted and there is still a bad morphology, gradually reduce the feeding flow of cavity 5 from the middle position to both ends, and observe the product morphology of the composite material at the outlet 4 until there is no bad morphology on the surface. Then stop adjusting the feeding flow. Regardless of how the feeding flow is adjusted, the feeding flow in each cavity 5 should meet the following rules: Q1>Q2>Q3>……>Q N , Q 2N-1 >Q 2N-2 >Q 2N-3 >……>Q N , to meet the principle of high tension and small feed.

[0060] After the above steps, the fiber path is changed through tension adjustment, and the impregnation area of ​​the resin melt on the fiber is increased. Through multi-stage feeding with different proportions and the principle of high tension and small feeding, the excessively concentrated melt resistance is avoided to cause limited breakage. At the same time, the multi-stage feeding repeatedly impregnates the fiber to achieve melt coating of the fiber, thereby effectively improving the impregnation effect.

[0061] In the specific contents of the above-mentioned specific implementation methods, the various technical features can be combined in any non-contradictory manner. In order to make the description concise, not all possible combinations of the above-mentioned technical features are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0062] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A tension-adjustable impregnation mold, characterized in that: The impregnation mold comprises an upper template (1), a lower template (2) and a mold cavity formed around the upper template (1) and the lower template (2), wherein a fiber feed port (3) and a discharge port (4) are respectively provided at both ends of the mold cavity, and the mold cavity comprises a plurality of cavities (5) connected in end-to-end order, wherein each cavity (5) is provided with an impregnation roller (6) that can be rotated to adjust the fiber tension, and each cavity (5) is connected with a melt feed port (7) for feeding a resin melt, wherein the fiber enters from the fiber feed port (3), bypasses the outer periphery of each impregnation roller (6), is impregnated with the resin melt in the cavity (5), and then is discharged from the discharge port (4); The upper template (1) is provided with a plurality of first corrugated surfaces (8), the lower template (2) is provided with a plurality of second corrugated surfaces (9) symmetrically arranged with respect to the first corrugated surfaces (8), the cavity (5) is formed between the first corrugated surfaces (8) and the second corrugated surfaces (9), the minimum distance between the first corrugated surfaces (8) and the second corrugated surfaces (9) is D1, the maximum distance between the first corrugated surfaces (8) and the second corrugated surfaces (9) is D2, and along the direction from the fiber feed port (3) to the discharge port (4), the distance between the first corrugated surface (8) and the second corrugated surface (9) gradually increases from D1 to D2, and then gradually decreases from D2 to D1; The impregnation roller (6) is an elliptical roller, the center of the elliptical roller coincides with the center of the cavity (5), the short axis diameter of the elliptical roller is greater than the minimum distance between the first corrugated surface (8) and the second corrugated surface (9), and the long axis diameter of the elliptical roller is less than the maximum distance between the first corrugated surface (8) and the second corrugated surface (9), and the fibers are staggered around the lower end surface of the first corrugated surface (8) and the upper surface of the elliptical roller in the mold cavity, or staggered around the upper end surface of the second corrugated surface (9) and the lower surface of the elliptical roller.

2. The tension-adjustable impregnation mold according to claim 1, characterized in that: The tension generated by the impregnation roller (6) in the first cavity (5) on the fiber and the tension generated by the impregnation roller (6) in the last cavity (5) on the fiber are smaller than the tension generated by any impregnation roller (6) in the middle position on the fiber; the feeding flow rate of the melt feed port (7) in the first cavity (5) and the feeding flow rate of the melt feed port (7) in the last cavity (5) are larger than the feeding flow rate of the melt feed port (7) in any cavity (5) in the middle position.

3. The tension-adjustable impregnation mold according to claim 2, characterized in that: The tension generated by the impregnation roller (6) in the first cavity (5) on the fiber is not greater than the tension generated by the impregnation roller (6) in the last cavity (5) on the fiber, and the feeding flow rate of the melt feed port (7) in the first cavity (5) is not less than the feeding flow rate of the melt feed port (7) in the last cavity (5).

4. The tension-adjustable impregnation mold according to claim 2, characterized in that: The number of the cavities (5) is 2N-1, wherein N≥2 and N is a positive integer; the tension exerted on the fiber by the impregnation roller (6) in each cavity (5) is recorded as F1, F2...F N 、F N+1 ...F 2N-1 , then, F1 <F2<F3<……<F N , F 2N-1 <F 2N-2 <F 2N-3 <…… <F N The feed flow rate in each cavity (5) is recorded as Q1, Q2...Q N , Q N+1 ...Q 2N-1 , then, Q1>Q2>Q3>……>Q N , Q 2N-1 >Q 2N-2 >Q 2N-3 >……>Q N .

5. The tension-adjustable impregnation mold according to claim 1, characterized in that: The same cavity (5) is connected to two groups of melt feed ports (7), the axes of the two melt feed ports (7) of the same cavity (5) coincide with each other, the axes of the melt feed ports (7) pass through the center of the cavity (5), and the axes of the melt feed ports (7) are perpendicular to the axis of the fiber feed port (3).

6. The tension-adjustable impregnation mold according to any one of claims 1 to 5, characterized in that: The invention also includes a controller (13) and a driving motor (14) connected to the impregnation roller (6); a flow valve module is provided at the melt feed port (7); an identification module (12) for identifying the surface morphology of the product is provided at the discharge port (4); the identification module (12) is connected to the input end of the controller (13); and the driving motor (14) and the flow valve module are both connected to the output end of the controller (13).

7. A dipping method based on the tension-adjustable dipping mold according to any one of claims 1 to 6, characterized in that: The following steps are involved: S10. The fiber is pulled so that the fiber enters from the fiber feed port (3), bypasses the periphery of each impregnation roller (6), and is led out from the discharge port (4); S20. A resin melt is fed into each cavity (5) from each melt feed port (7), the resin melt enters the cavity (5) and impregnates the fiber in the cavity (5); S30 observes the product morphology of the composite material at the discharge port (4). If the product surface has a poor morphology, the process proceeds to step S40; S40. Rotate the impregnation roller (6) to adjust the tension of the fibers in each cavity (5): first adjust the impregnation roller (6) in the middle position to increase the tension of the fibers in the middle position, and observe the product morphology of the composite material at the discharge port (4); if the product morphology is acceptable, the adjustment is terminated; if the product surface still has undesirable morphology, gradually increase the tension of the fibers from the middle position toward the ends, and observe the product morphology of the composite material at the discharge port (4) until the surface has no undesirable morphology, and then terminate the tension adjustment; S50. Adjust the tension of the fibers in each cavity (5) obtained in step S40 to continuously produce fiber-reinforced resin composite materials.

8. A dipping method based on the tension-adjustable dipping mold according to claim 7, characterized in that: Step S40 also includes the step of synchronously adjusting the feeding flow of each melt feed port (7): first adjusting the middle position cavity (5) to reduce the feeding flow of the middle position cavity (5), and observing the product morphology of the composite material at the discharge port (4); if the product morphology is qualified, then the adjustment is ended; if there is still a bad morphology on the product surface, then gradually reducing the feeding flow of the cavity (5) from the middle position to both ends, observing the product morphology of the composite material at the discharge port (4), until there is no bad morphology on the surface, then the feeding flow adjustment is ended.

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