A device for gluing reinforcement material

Abstract

The present application relates to a kind of reinforcing material gluing device, including glue tank, glue tank is filled with glue liquid for the impregnation of reinforcing material, impregnation roller is arranged in glue tank, two ends of impregnation roller are rotatably connected with the tank wall of glue tank, high-frequency vibrating type float roller is further arranged in glue tank, high-frequency vibrating type float roller is located directly below impregnation roller, and the density of high-frequency vibrating type float roller is less than the density of glue liquid in glue tank.The present application uses high-frequency vibrating type float roller, piezoelectric ceramic installed in the first hollow wing plate, piezoelectric ceramic installed in the second hollow wing plate, the cooperation of two different frequencies can effectively eliminate the air bubble and micron bubble in reinforcing material after gluing, and the degassing and defoaming effect is good.

Description

Technical Field

[0001] This invention relates to a gluing device for reinforcing materials, belonging to the field of mechanical equipment technology. Background Technology

[0002] During the resin coating process of reinforcing materials (such as fiberglass yarn, fiberglass cloth, and fiberglass mat), if air bubbles trapped during resin impregnation are not effectively removed, they can easily lead to porosity or delamination defects after curing. Taking epoxy resin prepreg as an example, when its porosity exceeds 0.5%, the mechanical properties of the composite material are significantly affected. For instance, an accident analysis of the wing skin of a certain type of UAV showed that a dense cluster of air bubbles with a diameter of 1.2 mm could reduce bending stiffness by 37%. Therefore, effectively removing air bubbles from the resin and fiber gaps during continuous coating is crucial to ensuring the quality of the prepreg.

[0003] Traditional coating equipment typically uses impregnation rollers inside a glue tank. Reinforcing material (such as fiberglass cloth, or simply peelable fiber cloth) is introduced into the glue tank and passes around the impregnation rollers to impregnate the resin. However, this simple impregnation method is difficult to effectively remove air bubbles trapped between fiber bundles and inside the resin, often failing to meet the requirements of products with strict low porosity requirements.

[0004] To obtain prepregs with lower porosity, vacuum coating is commonly used, which involves applying negative pressure to the coating area to aid in degassing. While vacuum coating equipment effectively reduces product porosity, it is expensive, and maintaining a high level of system sealing is essential for continuous fiberglass cloth production, leading to complex equipment and challenging process control. Furthermore, the negative pressure environment can cause uneven coating, often requiring a non-vacuum secondary coating process to adjust the resin content. This secondary coating may introduce new air bubbles (although mostly concentrated on the surface of the prepreg), further increasing process complexity and control difficulty.

[0005] To reduce equipment costs, ultrasonic degassing technology has been attempted for application in adhesive application equipment. Ultrasonic degassing primarily utilizes the cavitation effect and acoustic flow generated by ultrasound in liquids: alternating positive and negative pressure phases form numerous microbubbles and disrupt the original bubble structure, while the acoustic flow causes these microbubbles to aggregate, rise to the liquid surface, and be discharged. In practical applications, ultrasonic degassing devices typically immerse the ultrasonic transmitter in the adhesive solution, ensuring that the transmitter does not directly contact the fiberglass cloth. The main reason for this is that if the transmitter directly contacts the fiberglass cloth, the ultrasonic energy would be concentrated on the fiber cloth: firstly, any change in the fiberglass cloth's feeding speed would cause the high-frequency vibration and reaction force applied by the fixed ultrasonic transmitter to easily deform or displace the fiber mesh; secondly, the constant feeding speed required for direct contact severely restricts the flexibility of production cycle time. Due to this limitation of non-contact arrangement, the effective transmission of ultrasonic energy into the fiber gaps is significantly weakened, limiting the degassing capacity. Practice has shown that conventional ultrasonic degassing and gluing devices can generally only control the porosity of fiberglass prepreg to within 1%, which can only meet the requirements of conventional use.

[0006] When the reinforcing material is carbon fiber, especially carbon fiber felt, the bubble problem becomes even more pronounced. Carbon fiber itself has poor wettability with epoxy resin, and the internal fibers of carbon fiber felt are randomly and irregularly arranged, making it extremely easy to trap more air and form millimeter- to micrometer-sized bubble clusters. Numerous experiments have shown that when using conventional ultrasonic degassing devices to coat carbon fiber cloth, the porosity is often above 1.5%; while for carbon fiber felt, the porosity is as high as 3.2% or more. Therefore, for high-performance prepregs made of carbon fiber, currently, expensive vacuum coating equipment is still required. However, even with vacuum coating, the product yield can only reach about 77%, highlighting a significant trade-off between cost and yield.

[0007] It is evident that existing gluing devices suffer from shortcomings when dealing with difficult-to-wet reinforcing materials such as carbon fiber felt, including poor degassing, high equipment costs, limited processing capabilities, and low yield rates. Therefore, there is an urgent need for a gluing device that can efficiently remove air bubbles from resin and fibers, and is particularly suitable for disordered reinforcing materials such as carbon fiber felt. Summary of the Invention

[0008] This invention addresses the shortcomings of existing technologies by providing a device for applying adhesive to reinforcing materials. The specific technical solution is as follows:

[0009] A device for applying adhesive to reinforcing materials includes an adhesive tank containing an adhesive solution for impregnating reinforcing materials. An impregnation roller is disposed inside the adhesive tank, with its two ends rotatably connected to the tank wall. A high-frequency vibrating floating roller is also disposed inside the adhesive tank, located directly below the impregnation roller. The density of the high-frequency vibrating floating roller is less than the density of the adhesive solution in the adhesive tank.

[0010] In a further improvement, the high-frequency vibrating floating roller includes a hollow circular roller, on both sides of which a first hollow wing plate and a second hollow wing plate are integrally provided respectively. A piezoelectric ceramic is fixedly installed on the inner wall of the first hollow wing plate, and the piezoelectric ceramic is used to apply high-frequency vibration to the first hollow wing plate / second hollow wing plate.

[0011] In a further improvement, the first hollow wing plate and the second hollow wing plate have the same structure and the same volume, but the center frequency of the piezoelectric ceramic in the first hollow wing plate is not the same as the center frequency of the piezoelectric ceramic in the second hollow wing plate.

[0012] In a further improvement, after the reinforcing material enters the glue tank, it first passes through the first side of the dipping roller, then around the bottom side of the dipping roller, then through the second side of the dipping roller, and finally exits from the glue tank.

[0013] The first hollow wing plate is on the same side as the first side of the dip roller, and the second hollow wing plate is on the same side as the second side of the dip roller;

[0014] All the piezoelectric ceramics in the first hollow wing plate are installed on the lower side inside the first hollow wing plate, and all the piezoelectric ceramics in the second hollow wing plate are installed on the upper side inside the second hollow wing plate.

[0015] In a further improvement, the ratio of the center frequency of the piezoelectric ceramic in the second hollow wing plate to the center frequency of the piezoelectric ceramic in the first hollow wing plate is λ, where λ ≥ 17.

[0016] In a further improvement, the center frequency of the piezoelectric ceramic in the second hollow wing plate is f2, and the center frequency of the piezoelectric ceramic in the first hollow wing plate is f1, where 71kHz≤f1≤74kHz.

[0017] A further improvement is that the advancing speed of the reinforcing material within the glue tank is V. t V t / V0=f2 / f1, where V0 is the calibrated rate.

[0018] In a further improvement, a rotating shaft is installed at each end of the hollow roller, and a limiting clamp is provided on both sides of the rotating shaft to limit the vertical displacement of the rotating shaft. The limiting clamp is fixedly connected to the inner wall of the glue tank.

[0019] In a further improvement, the reinforcing material is yarn, cloth, or felt made of carbon fiber.

[0020] In a further improvement, the reinforcing material is a yarn, cloth, or felt made from one or more of the following: glass fiber, aramid fiber, basalt fiber, ultra-high molecular weight polyethylene fiber, alumina fiber, silicon carbide fiber, and plant fiber. Among these, common reinforcing materials made from plant fibers, such as wood pulp paper, serve as the core material of paper substrates (CEM-1, CEM-3).

[0021] The beneficial effects of this invention are:

[0022] 1. The present invention uses a high-frequency vibrating floating roller. The piezoelectric ceramics installed in the first hollow wing plate and the piezoelectric ceramics installed in the second hollow wing plate work together at two different frequencies to effectively eliminate large air bubbles and micron-sized air bubbles in the reinforcing material after gluing.

[0023] 2. This invention achieves low-porosity gluing in ordinary glue tanks by using ultrasonic-megason synergistic degassing under normal pressure, without the need for a vacuum system, thus achieving a degassing effect close to that of vacuum gluing and significantly reducing equipment investment and operation and maintenance costs.

[0024] 3. While conventional ultrasonic degassing (such as a single 73 kHz method) can break large bubbles, the cavitation effect generates dense new micron-sized bubbles that remain inside the prepreg. This invention introduces megasonic waves, whose gentle acoustic flow and microcavitation effect can effectively eliminate these secondary microbubbles, avoiding appearance defects such as pinhole clusters and localized resin accumulation.

[0025] 4. In existing ultrasonic transmitters fixed in the glue tank, when in direct contact with the reinforcing material, the ultrasonic energy is concentrated on the fibers, easily causing fiber mesh deformation, and the speed must be strictly controlled. This invention uses a suspended floating roller (density less than the glue solution). The hollow roller naturally presses against the reinforcing material below the glue-impregnated roller due to buoyancy. The vibration generated by the piezoelectric ceramic is indirectly transmitted through the wing plate and the glue solution. Most of the reaction force is buffered by the glue solution, avoiding concentrated impact on the fibers. The forward speed of the reinforcing material can be flexibly adjusted without damaging the fiber structure.

[0026] 5. The high-frequency vibrating floating roller adopts an integrated design of hollow round roller and double-sided wing plates. By installing piezoelectric ceramics through the wing plates, stable suspension and dual-frequency vibration can be achieved without increasing the volume of the hollow round roller. At the same time, the "seesaw" structure of the wing plates effectively transmits the vibration to the glue impregnation area, making full use of the limited space in the glue tank.

[0027] 6. This invention is particularly suitable for resin coating of carbon fiber reinforced materials, with good defoaming effect; it can also be applied to ultra-high molecular weight polyethylene fiber cloth, and the porosity can be reduced to 0.58% with difficulty; however, when coating ultra-high molecular weight polyethylene fiber felt, the porosity is still greater than 1%, and the degassing effect needs to be further improved.

[0028] 7. The gluing and re-glueing processes of this invention can be automated through PLC control, meeting the requirements of intelligent production. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the reinforcing material coating device of the present invention;

[0030] Figure 2 This is a schematic diagram of the structure inside the glue tank described in this invention. Detailed Implementation

[0031] 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 and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0032] In the description of this invention, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and 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, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] 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 based on the specific circumstances.

[0034] Example 1

[0035] like Figure 1 , 2 As shown, a reinforcing material coating device includes a glue tank 10 containing a glue solution for impregnating a reinforcing material 20. An impregnation roller 11 is disposed inside the glue tank 10, with both ends of the roller 11 rotatably connected to the tank wall of the glue tank 10. A high-frequency vibrating floating roller is also disposed inside the glue tank 10, located directly below the impregnation roller 11. The density of the high-frequency vibrating floating roller is less than the density of the glue solution in the glue tank 10.

[0036] In some embodiments, the dip roller 11 is driven by a motor 40 and can be driven by some conventional transmission methods, such as belt drive.

[0037] In other embodiments, the gluing device of the present invention uses a motor as the core of power transmission and is equipped with a continuously variable speed control mechanism. The entire system is controlled by a PLC as the intelligent control center. By collecting input signals from field buttons, sensors and other sources, and performing internal program logic calculations, it accurately outputs control commands to adjust the motor speed and transmission status in real time, thereby achieving stepless smooth speed change, automatic start and stop, adaptive adjustment of working conditions and monitoring and protection of operating faults. The entire process is automated and intelligent, achieving precise transmission and speed control.

[0038] In some other embodiments, to facilitate the replacement of adhesive in the adhesive tank 10, a discharge valve 30 is installed at the bottom of the adhesive tank 10; when the discharge valve 30 is opened, the adhesive in the adhesive tank 10 can be drained. New adhesive can be introduced into the adhesive tank 10 through a diaphragm pump and pipeline.

[0039] In other embodiments, the glue tank uses a diaphragm pump as the liquid replenishment actuator. The liquid level signal in the glue tank is collected in real time by a level gauge and transmitted to the PLC. The PLC compares the detected liquid level with the set upper and lower limit liquid level values. When the liquid level is lower than the lower limit set value, the diaphragm pump is automatically started to replenish the liquid. When the upper limit set value is reached, the liquid replenishment is stopped immediately. This realizes closed-loop automatic control of the liquid level in the glue tank, ensuring stable, continuous, and accurate automatic replenishment of the liquid level in the glue tank.

[0040] The high-frequency vibrating floating roller includes a hollow circular roller 50. A first hollow wing plate 51 and a second hollow wing plate 52 are integrally provided on both sides of the hollow circular roller 50. A piezoelectric ceramic is fixedly installed on the inner wall of the first hollow wing plate 51. The piezoelectric ceramic is used to apply high-frequency vibration to the first hollow wing plate 51 / second hollow wing plate 52.

[0041] The first hollow wing plate 51 and the second hollow wing plate 52 have the same structure and the same volume. The center frequency of the piezoelectric ceramic in the first hollow wing plate 51 is not the same as the center frequency of the piezoelectric ceramic in the second hollow wing plate 52.

[0042] In this embodiment, if the adhesive in the adhesive tank 10 is an epoxy resin adhesive, its density is generally greater than or equal to 1.10 g / cm³. 3 Even with other resins, the density of the adhesive solution is definitely greater than 1 g / cm³. 3The hollow roller 50, the first hollow wing plate 51, and the second hollow wing plate 52 can all be made of polyamide 12 (commonly known as nylon 12), a high-performance engineering plastic and a semi-crystalline polymer. Due to its unique molecular structure, it possesses properties such as wear resistance, impact resistance, and chemical corrosion resistance. Its low density (1.03 g / cm³) 3 It features good processing fluidity; furthermore, the hollow roller 50, the first hollow wing plate 51, and the second hollow wing plate 52 are all hollow structures, and their nylon shells (the shells made by integrally molding the hollow roller 50, the first hollow wing plate 51, and the second hollow wing plate 52) can be 2mm thick; by processing them into hollow structures, it is easy to ensure that the density of the high-frequency vibrating floating roller is less than the density of the adhesive liquid in the adhesive tank 10. Even if sheet-like or block-shaped piezoelectric ceramics are installed inside the nylon shell, the impact is minimal, allowing the high-frequency vibrating floating roller to float on the adhesive liquid in the adhesive tank 10. Enamelled wire is used to connect the piezoelectric ceramics inside the high-frequency vibrating floating roller to the external controller. The enamelled wire is set to a sufficiently long length to provide sufficient redundancy to facilitate the displacement changes caused by the up-and-down floating of the high-frequency vibrating floating roller.

[0043] In some embodiments, a rotating shaft 53 is respectively installed at both ends of the hollow circular roller 50, and limiting clamps are respectively provided on both sides of the rotating shaft 53 to limit the vertical displacement of the rotating shaft 53. The limiting clamps are fixedly connected to the inner wall of the rubber groove 10. The rotating shaft 53 and the two limiting clamps on both sides have rolling friction, and the frictional resistance is small. The limitation of the limiting clamps and the rotating shaft 53 ensures that the high-frequency vibrating floating roller can only move up and down.

[0044] The gap between the limiting clamps only restricts the horizontal movement and axial movement of the rotating shaft, but does not restrict the rotational freedom of the rotating shaft around its own axis. When the first hollow wing plate and the second hollow wing plate are excited by piezoelectric ceramics at different frequencies or different installation positions, the two wing plates generate opposing torques, causing the hollow roller to oscillate back and forth at high frequency and small amplitude around the rotating shaft, thereby realizing a "seesaw"-like alternating squeezing action. At the same time, the rotating shaft can still slide up and down between the limiting clamps, allowing the floating roller as a whole to adaptively adjust the top pressure according to buoyancy, ensuring the independence and coexistence of vertical displacement and oscillation freedom.

[0045] like Figure 2 As shown, when the reinforcing material 20 enters the glue tank 10, it first passes through the first side of the dip roller 11, then around the bottom side of the dip roller 11, then through the second side of the dip roller 11, and finally exits from the glue tank 10.

[0046] The first hollow wing plate 51 is on the same side as the first side of the dip roller 11, and the second hollow wing plate 52 is on the same side as the second side of the dip roller 11.

[0047] All the piezoelectric ceramics in the first hollow wing plate 51 are installed on the lower side inside the first hollow wing plate 51, and all the piezoelectric ceramics in the second hollow wing plate 52 are installed on the upper side inside the second hollow wing plate 52.

[0048] During impregnation, the lowermost portion of the reinforcing material 20 on the impregnation roller 11 is continuously squeezed by the high-frequency vibrating floating roller. Because the density of the high-frequency vibrating floating roller is less than the density of the adhesive in the adhesive tank 10, the buoyancy of the high-frequency vibrating floating roller is greater than its own weight, ensuring that the top of the hollow roller 50 always presses against the lowermost portion of the reinforcing material 20 on the impregnation roller 11. Under the high-frequency vibration generated by the piezoelectric ceramic, the vibration effects (center frequencies of the piezoelectric ceramics differing by an order of magnitude) of the vibration sources (piezoelectric ceramics) on both sides of the wing plates (first hollow wing plate 51, second hollow wing plate 52) cause the first hollow wing plate 51 and the second hollow wing plate 52 to not maintain an absolutely horizontal state in the adhesive. The first hollow wing plate 51 and the second hollow wing plate 52 exhibit a slight "one above the other" distribution. Furthermore, the piezoelectric ceramics are also installed in an "one above the other" configuration within the first hollow wing plate 51 and the second hollow wing plate 52, further exacerbating this "one above the other" distribution. Finally, since the impregnation roller 11 is an active roller driven by external force, the friction from the advancing reinforcing material 20 further alters the degree of the "one above the other" distribution. For example, a higher advancing speed of the reinforcing material 20 will increase the height difference in the "one above the other" distribution between the first hollow wing plate 51 and the second hollow wing plate 52, while a lower advancing speed will decrease the height difference.

[0049] The ratio of the center frequency of the piezoelectric ceramic in the second hollow wing plate 52 to the center frequency of the piezoelectric ceramic in the first hollow wing plate 51 is λ, where λ ≥ 17. The center frequency of the piezoelectric ceramic in the second hollow wing plate 52 is f2, and the center frequency of the piezoelectric ceramic in the first hollow wing plate 51 is f1, where 71kHz ≤ f1 ≤ 74kHz. The forward speed of the reinforcing material 20 in the glue tank 10 is V. t V t / V0=f2 / f1, where V0 is the calibration rate. V0 is a known value that can be calibrated beforehand for different adhesives and different reinforcing materials.

[0050] Since the high-frequency vibrating floating roller is similar to a seesaw structure, its fulcrum is the contact area between the top of the hollow roller 50 and the reinforcing material 20. Therefore, when the two sides of the hollow roller 50 are subjected to high-frequency vibrations of different degrees, after the two sides balance and cancel out some of the vibration, most of the remaining vibration will act on the bottom part of the reinforcing material 20 of the glue-impregnated roller 11. The high-frequency vibrating floating roller itself is mainly suspended by buoyancy. Even if the hollow roller 50 is in direct contact with the reinforcing material 20, only a small part of the reaction force generated by the high-frequency vibration will act directly on the fiberglass cloth. Most of the reaction force generated by the high-frequency vibration is buffered and canceled by the surrounding glue.

[0051] Therefore, without the first hollow wing plate 51 and the second hollow wing plate 52, the hollow roller 50 would have to be very large to ensure the levitation effect, which would not make full use of the space. Secondly, the piezoelectric ceramic would have to be installed on both sides of the hollow roller 50. Without the first hollow wing plate 51 and the second hollow wing plate 52 to maintain balance, the hollow roller 50 itself may continuously and repeatedly "vibrate" (constantly rotating in small forward and reverse directions) during high-frequency vibration. This uncontrollable vibration effect may lead to uneven bubble removal. If any bubbles are missed, it can easily cause defects such as clusters of bubbles in local areas.

[0052] For carbon fibers, especially carbon fiber felt, the poor wettability and random internal pore structure make it very difficult to remove air bubbles; therefore, vibrations in a wider frequency range are needed to induce bubble rupture. The piezoelectric ceramic in the first hollow wing plate 51 primarily provides low-frequency, high-amplitude vibrations, while the piezoelectric ceramic in the second hollow wing plate 52 provides high-frequency, low-amplitude vibrations. These low-frequency, high-amplitude vibrations, through this seesaw-like structure, are ultimately transformed into impact and compression forces from the hollow roller 50 on the reinforcing material 20. Meanwhile, the high-frequency, low-amplitude vibrations (ultrasonic vibrations) are transmitted to the reinforcing material 20 via the nylon medium to eliminate bubbles in the area where the reinforcing material 20 is located. During the experiment, it was found that for the f1 low-frequency, high-amplitude vibration, due to its dominant cavitation effect, although cavitation can eliminate large bubbles, it itself generates dense small bubbles due to the presence of cavitation nuclei, making it unable to effectively eliminate micron-sized bubbles on a large scale. On the other hand, the f2 high-frequency, low-amplitude vibrations (megason vibrations) have a shorter wavelength and can penetrate deep into the liquid. The megason negative pressure causes the bubbles to expand, and the positive pressure causes the bubbles to annihilate, making it suitable for eliminating micron-sized bubbles.

[0053] For example, in this case, f1 = 73 kHz, f2 = 1241 kHz, λ = 17; for epoxy resin, the reinforcing material is carbon fiber felt, V0 can be 4.7 cm / min, V t =80cm / min.

[0054] The present invention is used to apply adhesive to thin carbon fiber felt (the thickness is generally less than 1 mm based on the cured carbon fiber felt prepreg). The resulting carbon fiber felt prepreg has no appearance defects such as pinholes, wrinkles, dry spots, missing adhesive, exposed fibers, or local resin accumulation.

[0055] Example 1 employs a high-frequency vibrating floating roller. The piezoelectric ceramics in the first hollow wing plate have a low-frequency center frequency (kHz level), while the piezoelectric ceramics in the second hollow wing plate have a high-frequency center frequency (MHz level), with a frequency difference of more than one order of magnitude. They are arranged in a specific direction (the low-frequency side is located on the feed side of the impregnation roller, and the high-frequency side is located on the discharge side). The forward speed of the reinforcing material is matched according to the calibrated speed-frequency ratio. Under these conditions, the resulting prepreg has a very low porosity (e.g., the industry-specified porosity is less than 1%) and exhibits no abnormal defects.

[0056] In other embodiments, if both piezoelectric ceramics are set to the same low frequency, and everything else is the same, analysis shows that low-frequency ultrasound (e.g., 73 kHz) mainly produces a strong cavitation effect, capable of breaking large bubbles larger than millimeters. However, during cavitation, a large number of micron-sized new bubbles (secondary bubbles) are generated due to the presence of cavitation nuclei. Due to the lack of the gentle acoustic flow and microcavitation effect of high-frequency megahertz (MHz level), these microbubbles cannot be effectively removed and instead remain in large quantities in the resin and fiber gaps, forming a dense cluster of pinholes after curing. Furthermore, the dual low-frequency vibrations are unidirectional and cannot form a "seesaw" dynamic compression, making it difficult to expel bubbles trapped between fiber bundles.

[0057] In some other embodiments, if both piezoelectric ceramics are set to the same high frequency, and everything else is the same, analysis shows that the high-frequency megasonic wavelength is relatively short and mainly acts on micron-sized bubbles, annihilating them through alternating positive and negative pressure. However, it lacks sufficient ability to cavitation and break up millimeter-sized large bubbles. Large bubbles trapped inside the reinforcing material (especially carbon fiber felt) cannot be effectively broken up or driven away by megasonic waves. These large bubbles occupy space during the impregnation process, causing the surrounding resin flow to be obstructed. After curing, the bubble sites form local resin enrichment (the bubbles are filled by resin after being expelled) or leave large pores. At the same time, the dual high frequencies lack the large amplitude mechanical impact force of low frequencies, and cannot exert an effective squeezing effect on the fiber bundle, making it difficult for large bubbles to be expelled from the fiber gaps.

[0058] In some other embodiments, if the frequency values ​​on both sides are reversed (high frequency on the feed side, low frequency on the discharge side), and the rate remains unchanged, analysis shows that the frequency arrangement direction of the present invention is strictly coupled with the direction of the reinforcing material's movement: the low frequency on the feed side (first side) pre-degassing the resin containing bubbles, breaking large bubbles; the high frequency on the discharge side (second side) then eliminates microbubbles generated by cavitation. After the direction is reversed, the high frequency on the feed side cannot effectively handle large bubbles, and a large number of large bubbles enter the impregnation zone with the reinforcing material; subsequently, the low frequency on the discharge side generates strong cavitation, which not only fails to eliminate existing large bubbles but also generates a large number of new microbubbles, leading to bubble accumulation. Furthermore, the rate matching condition V... t When / V0=f2 / f1 is disrupted, the vibration energy cannot coordinate with the material's forward speed, which can easily lead to uneven resin impregnation, localized lack of resin forming dry spots, and pinhole clusters.

[0059] In some other embodiments, if only the high-frequency side vibration is retained (low-frequency side shut off), analysis shows that while retaining only high-frequency megasonic waves can suppress microbubbles, it cannot break up and expel the original large bubbles between fiber bundles and in the resin. These large bubbles are partially compressed or moved by the megasonic waves in subsequent processes, but are not completely eliminated, easily forming visible pores (pinhole clusters) after curing. Simultaneously, the lack of the large-amplitude impact and compression effect of low-frequency ultrasound makes it difficult to effectively open the fiber gaps within the reinforcing material, resulting in insufficient resin wetting and bubble retention.

[0060] In some other embodiments, if only the low-frequency side vibration is retained (high-frequency side shut off), analysis shows that while the cavitation effect of single low-frequency ultrasound can break up large bubbles, a large number of microbubbles are generated and remain. These microbubbles accumulate on the fiber surface or within the resin, hindering uniform resin flow and leading to either excessive (resin enrichment) or insufficient (fiber exposure) resin in localized areas. Furthermore, the large amplitude mechanical action of low-frequency vibration, without high-frequency acoustic buffering, may cause intense localized resin disturbances, displacing the disordered structure of the fiber felt and resulting in resin deficiency in some areas.

[0061] In some other embodiments, if the shaft of the high-frequency vibrating floating roller is fixedly connected to the inner wall of the glue tank, it cannot float up and down (i.e., it loses its levitation function); after analysis, the levitation characteristic of the high-frequency vibrating floating roller is one of its core designs; the floating roller relies on buoyancy to naturally press against the reinforcing material, and transmits the vibration indirectly and evenly to the inside of the fiber through the glue, while most of the reaction force is buffered by the glue, avoiding concentrated impact on the fiber; when the floating roller is fixed, it is equivalent to a rigid ultrasonic emitting rod directly contacting the reinforcing material, which may lead to:

[0062] 1) Concentrated energy impacts the fibers. Ultrasonic energy acts directly on the fibers, easily causing deformation, displacement, or breakage of the disordered structure of carbon fiber felt, resulting in localized glue deficiency and exposed fibers.

[0063] 2) Uneven vibration transmission. Fixed contact prevents vibration from being evenly distributed through the flow and buffering of the adhesive. Instead, it generates excessive mechanical stress at the contact point, hindering the expulsion of air bubbles and even pressing surface air bubbles into the fiber interior.

[0064] 3) Loss of dynamic top pressure. The floating roller cannot adaptively adjust the top pressure according to changes in the tension or thickness of the reinforcing material, and cannot form a "seesaw"-like alternating squeezing-releasing action, so air bubbles cannot be effectively driven out of the fiber gaps.

[0065] Therefore, the degassing effect under stationary conditions deteriorates significantly, and high porosity and severe defects are very likely to occur.

[0066] In summary, the superior degassing effect of this invention relies on the coupling of three key mechanisms: low-frequency and high-frequency dual-frequency synergy, direction and rate matching, and dynamic top pressure from the floating roller suspension. Deviation from any of these conditions (single frequency, reversed direction, rate mismatch, fixed floating roller) will disrupt this synergistic system, easily leading to a significant increase in porosity and various appearance defects.

[0067] Furthermore, analysis shows that the device and control method of the present invention are suitable for structurally ordered and stable fiberglass cloths, where the porosity can be controlled at a very low level. However, for thicker carbon fiber felt prepregs (e.g., thicker than 1 mm), the difficulty of degassing increases significantly due to the thickness. Using the device of Embodiment 1 of the present invention for gluing and degassing may result in appearance defects such as exposed fibers.

[0068] For V t / V0=f2 / f1, according to this rule, in order to satisfy the adaptive V t The only way to meet the requirements is to adjust f2 to satisfy the glue application needs.

[0069] The function of λ is to enable the ultrasonic and megaphonic vibrations to couple according to a certain pattern, thereby generating vibrations that meet the requirements for defoaming. If λ is too small, the antagonism between the two will intensify in different regions of the piezoelectric ceramics, which may cause additional appearance defects; if λ is too large, the defoaming effect of the megaphonic frequency will not be as expected.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for applying adhesive to reinforcing materials, comprising an adhesive tank containing an adhesive solution for impregnating reinforcing materials, wherein an impregnation roller is disposed inside the adhesive tank, and both ends of the impregnation roller are rotatably connected to the tank wall, characterized in that: The glue tank is also equipped with a high-frequency vibrating floating roller, which is located directly below the glue-dipping roller. The density of the high-frequency vibrating floating roller is less than the density of the glue liquid in the glue tank.

2. The adhesive applicator for reinforcing materials according to claim 1, characterized in that: The high-frequency vibrating floating roller includes a hollow circular roller, on both sides of which a first hollow wing plate and a second hollow wing plate are integrally provided. A piezoelectric ceramic is fixedly installed on the inner wall of the first hollow wing plate, and the piezoelectric ceramic is used to apply high-frequency vibration to the first hollow wing plate / second hollow wing plate.

3. The adhesive applicator for reinforcing materials according to claim 1, characterized in that: The first hollow wing plate and the second hollow wing plate have the same structure and the same volume, but the center frequency of the piezoelectric ceramic in the first hollow wing plate is not the same as the center frequency of the piezoelectric ceramic in the second hollow wing plate.

4. The adhesive applicator for reinforcing materials according to claim 2, characterized in that: After entering the glue tank, the reinforcing material first passes through the first side of the dipping roller, then around the bottom side of the dipping roller, then through the second side of the dipping roller, and finally exits from the glue tank. The first hollow wing plate is on the same side as the first side of the dip roller, and the second hollow wing plate is on the same side as the second side of the dip roller; All the piezoelectric ceramics in the first hollow wing plate are installed on the lower side inside the first hollow wing plate, and all the piezoelectric ceramics in the second hollow wing plate are installed on the upper side inside the second hollow wing plate.

5. The adhesive applicator for reinforcing materials according to claim 3, characterized in that: The ratio of the center frequency of the piezoelectric ceramic in the second hollow wing plate to the center frequency of the piezoelectric ceramic in the first hollow wing plate is λ, where λ ≥ 17.

6. The adhesive applicator for reinforcing materials according to claim 5, characterized in that: The center frequency of the piezoelectric ceramic in the second hollow wing plate is f2, and the center frequency of the piezoelectric ceramic in the first hollow wing plate is f1, where 71kHz≤f1≤74kHz.

7. The adhesive applicator for reinforcing materials according to claim 6, characterized in that: The advancing speed of the reinforcing material in the glue tank is V. t V t / V0=f2 / f1, where V0 is the calibrated rate.

8. The adhesive applicator for reinforcing materials according to claim 2, characterized in that: The hollow roller is equipped with a rotating shaft at both ends, and a limiting clamp is provided on both sides of the rotating shaft to limit the vertical displacement of the rotating shaft. The limiting clamp is fixedly connected to the inner wall of the glue tank.

Images