A two-step prepreg film tension deformation control device

Abstract

This invention relates to a film tension deformation control device for a two-step prepreg machine, comprising a film drive device, a DC brushless motor, a damping torque device, a force sensor, and a vision inspection device. The film drive device propels the film forward. The DC brushless motor is connected to the film drive device and drives the conveyor belt of the film drive device to rotate. The force sensor is sequentially connected to the DC brushless motor and the damping torque device, and is used to analyze and transmit the measured horizontal force change signal at the position of the paper feed roller in the film drive device to the DC brushless motor and the damping torque device. The damping torque device is used to adjust the damping of the film. The vision inspection device is located at the outlet end of the film drive device and is used to monitor the tension of the film. The purpose of this two-step prepreg machine film tension deformation control device is to solve the problems of prepreg wrinkling and bubbling caused by tension deformation during the production of prepreg in existing two-step equipment.

Description

Technical Field

[0001] This invention relates to the field of composite material preparation technology, specifically to a two-step prepreg film tension deformation control device. Background Technology

[0002] In the two-step production process of prepreg sheets, on commonly used equipment, the prepreg is mostly composed of multiple adhesive films, fabric unwinding rollers, multiple pressure rollers, and multiple bundles of fibers, which are then collected on a single take-up roller after a composite process. The take-up roller, unwinding roller, pressure roller, and various auxiliary rollers on the equipment all provide traction torque and unwinding torque in the opposite direction. Except for the take-up roller, the other rollers also provide frictional force in the opposite direction to the prepreg's movement. The traction force, unwinding torque, and frictional force together constitute the tension applied to the prepreg. Since prepreg products are mostly composed of prepreg and release paper and PE release film on top and bottom, the tension applied to the prepreg mentioned above is decomposed across multiple layers of material. Part of this tension is transferred to the internal energy of the resin and PE release film in the prepreg. This energy is determined by its modulus. Because the elastic modulus of the resin and PE release film is much smaller than the modulus of the fibers, fabric, and release paper, this part of the energy is simplified and not considered in this patent. The tension on the prepreg will stretch the fabric and release paper, causing tensile deformation. The deformation will recover after the prepreg is cut and wound up. The inconsistency between the shrinkage of the release paper and the reinforcing fabric will cause the prepreg fibers to arch or bubble, resulting in prepreg defects and affecting the quality level of subsequent processes such as filament cutting, tape cutting and automatic laying of composite materials.

[0003] With the continuous advancement of technology in two-step prepreg manufacturers, they have gradually realized the importance of tension control during production for product quality. Therefore, most current equipment is equipped with independent power units for different rollers and tension detection devices. Some newer machines also include tension control devices that adjust according to the tension detected during production. However, under current prepreg production tension, due to the high modulus of carbon fiber, its deformation is generally less than 1μm. Under a constant tension of 500N, the deformation of T700 grade carbon fiber is generally around 0.37μm. Although newer equipment can control this, to ensure prepreg quality, tension applied to the release paper of the film carrier still exists, and release paper deformation still exists. In long-term production, bubbling problems in the final product due to the difference in deformation can still occur. Furthermore, older two-step tension machines are difficult to modify and cannot correct this problem.

[0004] Therefore, the inventors have provided a two-step prepreg film tension deformation control device. Summary of the Invention

[0005] (1) Technical problems to be solved

[0006] This invention provides a two-step prepreg film tension deformation control device, which solves the technical problems of prepreg wrinkling and bubbling caused by tension deformation during the production of prepreg in existing two-step equipment.

[0007] (2) Technical solution

[0008] This invention provides a two-step prepreg machine film tension deformation control device, including a film transmission device, a DC brushless motor, a damping torque device, a force sensor, and a vision inspection device; wherein,

[0009] The film transmission device is used to drive the film forward. The brushless DC motor is connected to the film transmission device and is used to drive the transmission belt of the film transmission device to rotate. The force sensor is connected to the brushless DC motor and the damping torque device in sequence and is used to analyze and transmit the measured change signal of the horizontal force at the position of the paper feed roller in the film transmission device to the brushless DC motor and the damping torque device. The damping torque device is used to adjust the damping of the film.

[0010] The visual inspection device is located at the outlet end of the film transmission device and is used to monitor the tension of the film.

[0011] Furthermore, the film transmission device includes a lower conveyor belt wider than the maximum width of the prepreg product and an upper conveyor belt placed above both sides of the lower conveyor belt, wherein the distance between the two upper conveyor belts is less than the maximum width of the prepreg product.

[0012] Furthermore, the upper conveyor belt is provided with irregular protrusions and depressions.

[0013] Furthermore, the outer surface of the upper conveyor belt and / or the lower conveyor belt is a rubber surface with a high coefficient of friction.

[0014] Furthermore, the damping torque device is an adjustable linear spring or an electromagnetic spring.

[0015] Furthermore, the visual inspection device includes a material platform and multiple point light sources disposed on the material platform, the end of which is connected to the prepreg production plane.

[0016] Furthermore, the upper surface of the material platform is a plurality of smooth curved surfaces connected in sequence, and the extension direction of the smooth curved surfaces is parallel to the travel direction of the prepreg.

[0017] Furthermore, the smooth surface is a sinusoidal waveform surface.

[0018] Furthermore, the waveform frequency of the sinusoidal waveform surface decreases sequentially along the travel direction of the prepreg.

[0019] Furthermore, the brushless DC motor is a brushless DC servo motor and is controlled by a microcontroller.

[0020] (3) Beneficial effects

[0021] In summary, during operation, this invention first guides the film through the film transmission device of the device before it enters the lamination process during prepreg production. The film transmission device is adjusted to clamp both sides of the film. Then, the DC brushless motor is started, and the prepreg machine is activated. The DC brushless motor is adjusted to a fixed linear speed for prepreg production, and the damping torque device is adjusted according to the frequency of force sensor readings. Once the force sensor reading amplitude drops below a preset value, the speed of the DC brushless motor is adjusted based on the force sensor reading. After the equipment adjustment is complete, the film on the vision inspection device is observed to see if it has moved forward. Through this process, the radial deformation of the film caused by tension during the film feeding to the lamination process is completely reduced, achieving zero deformation difference between the film and the reinforcing material. This solves the problem of wrinkling or bubbling in the prepreg product coding, improving the quality of raw materials for subsequent composite material production processes. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention 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.

[0023] Figure 1 This is a schematic diagram of the structure of a two-step prepreg film tension deformation control device provided in an embodiment of the present invention.

[0024] In the picture:

[0025] 1- Adhesive film; 2- Adhesive film transmission device; 201- Upper conveyor belt; 202- Lower conveyor belt; 3- DC brushless motor; 4- Damping torque device; 5- Force sensor; 6- Vision inspection device; 601- Material platform; 602- Point light source. Detailed Implementation

[0026] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present invention by way of example, but should not be used to limit the scope of the present invention. That is, the present invention is not limited to the described embodiments, and any modifications, substitutions and improvements to the parts, components and connection methods are covered without departing from the spirit of the present invention.

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] Figure 1 This is a schematic diagram of a two-step prepreg machine film tension deformation control device provided in an embodiment of the present invention. The control device may include a film transmission device 2, a DC brushless motor 3, a damping torque device 4, a force sensor 5, and a vision detection device 6. The film transmission device 2 drives the film 1 forward. The DC brushless motor 3 is connected to the film transmission device 2 and drives the conveyor belt of the film transmission device 2 to rotate. The force sensor 5 is sequentially connected to the DC brushless motor 3 and the damping torque device 4 and is used to analyze and transmit the measured horizontal force change signal at the position of the paper feed roller in the film transmission device 2 to the DC brushless motor 3 and the damping torque device 4. The damping torque device 4 is used to adjust the damping of the film 1. The vision detection device 6 is located at the outlet end of the film transmission device 2 and is used to monitor the tension of the film 1.

[0029] In the above embodiments, the DC brushless motor 3 can perform constant speed control on the film transmission device 2, while minimizing the torque change of the AC motor in constant speed state, and controlling the torque change of the prepreg motor in constant speed state after the tension deformation control device.

[0030] The damping torque device 4 is connected to the force sensor 5 and controlled by a microcontroller with preset parameters. The damping torque device 4 is located below the film transmission device 2 to adjust the damping of the film 1 on it. The preset parameters of the microcontroller are calculated based on the radial tensile modulus of the reinforcing material (fiber fabric or unidirectional fiber tape) and auxiliary material (release paper or release film) used in the prepreg production. This algorithm can be expressed in programmable form. When the force sensor 5 collects the horizontal stress on the film transmission device 2, if the direction of the horizontal stress is consistent with the direction of film travel, the speed of the brushless DC motor 3 should be increased according to the preset parameters; if the direction of the horizontal stress is opposite to the direction of film travel, the speed of the brushless DC motor 3 should be decreased according to the preset parameters.

[0031] Among these methods, the horizontal tension control method has significant advantages over the traditional method of adjusting tension by changing the vertical axis position. The traditional method of controlling fabric / yarn tension involves adding a shaft / roller along the fabric / yarn travel path and adjusting its horizontal position to apply a vertical component of force to the fabric / yarn to adjust its axial tension. This method significantly increases the travel of the fabric / yarn between the traction roller and the unwind roller, and the adjustment process can cause material accumulation or slippage during the winding process. The horizontal tension control method minimizes the travel variation between the traction roller and the unwind roller, and concentrates as much of the accumulation and slippage that may exist on the traction roller and the unwind roller as possible on the unwind roller. The unwind roller has a higher degree of freedom than the traction roller, so the horizontal tension control method can effectively improve the quality level of the product.

[0032] In a preferred embodiment, the film conveyor 2 includes a lower conveyor belt 202 that is wider than the maximum width of the prepreg product and an upper conveyor belt 201 placed above both sides of the lower conveyor belt 202. The distance between the two upper conveyor belts 201 is less than the maximum width of the prepreg product.

[0033] Specifically, all three devices are powered by the aforementioned DC motors, and there is no speed difference between them. When the devices are in use, the surface of the lower conveyor belt 202 should be at least 50mm higher than the prepreg composite plane. At the same time, the upper conveyor belts 201 on both sides clamp the adhesive film 1 to achieve the function of constant speed paper feeding.

[0034] The arrangement of upper and lower conveyor belts ensures that the surface of the film 1 is relatively flat during travel. Both sides of the upper conveyor belt 201 and the lower conveyor belt 202 are equipped with drive wheels. The drive wheels are coaxially connected to the output shaft of the DC brushless motor 3 and rotate under the drive of the DC brushless motor 3, thereby driving the corresponding upper conveyor belt 201 and lower conveyor belt 202 to rotate synchronously, thus realizing the transport of the film 1.

[0035] In a preferred embodiment, the upper conveyor belt 201 has irregular protrusions and depressions. These protrusions and depressions are designed to prevent stress concentration during the paper feeding process, and the belt length should be controlled to be below 500mm.

[0036] In a preferred embodiment, the outer surfaces of the upper conveyor belt 201 and / or the lower conveyor belt 202 are rubber surfaces with a high coefficient of friction. The use of rubber surfaces on the conveyor belts increases the friction between the conveyor belt and the rubber film 1, thereby ensuring the stable movement of the rubber film 1 on the conveyor belt.

[0037] In a preferred embodiment, the damping torque device 4 is an adjustable linear spring or an electromagnetic spring. In the existing prepreg production process, there are variations in the shaft torque due to changes in the radius of the yarn beam and the conveyor roller, as well as variations in the torque due to the working principle of the AC motor. This damping torque device 4 adjusts the damping based on the frequency of change fed back by the force sensor 5.

[0038] In a preferred embodiment, the visual inspection device 6 includes a material platform 601 and multiple point light sources 602 disposed on the material platform. The end of the material platform 601 is connected to the prepreg production plane. Specifically, during the production process, the tension of the adhesive film is observed based on the scattered halo generated by the point light sources as they pass through the film, which facilitates the monitoring and manual adjustment of the equipment by production personnel.

[0039] In a preferred embodiment, the upper surface of the feed table 601 is composed of multiple sequentially connected smooth curved surfaces, the extension direction of which is parallel to the travel direction of the prepreg. The advantage of the smooth curved surfaces is that they conform to the material properties of the auxiliary material (release paper / release film). Since the auxiliary material (release paper / release film) is a continuous, smooth material, its fibrous structure means that if the material is bent, irreversible creases will form. Furthermore, to ensure the successful application of the vision inspection device 6, the release paper should adhere as closely as possible to the surface of the feed table 601. This requires that the feed table should not have discontinuous bends or surfaces with excessive curvature.

[0040] In a preferred embodiment, the smooth surface is a sinusoidal waveform surface. The sinusoidal waveform surface is a simple fit for connecting parabolas of different frequencies with the brachistochrone curve, facilitating manufacturing. Furthermore, compared to the material table 601 with excessively high or low curvature, the sinusoidal waveform surface effectively controls paper accumulation within the material table range, improving the effectiveness of visual inspection.

[0041] In a preferred embodiment, the frequency of the sinusoidal waveform gradually decreases along the travel direction of the prepreg. This continuous decrease in frequency helps to gradually bring the paper's travel plane back to the position required for production, effectively reducing paper accumulation problems caused by abrupt changes in curvature.

[0042] In a preferred embodiment, the brushless DC motor 3 is a brushless DC servo motor and is controlled by a microcontroller.

[0043] Example 1

[0044] A two-step prepreg machine film tension deformation control device includes a DC brushless motor 3, a film transmission device 2, a damping torque device 4, a force sensor 5, and a vision detection device 6. The DC brushless motor 3 is controlled by a microcontroller, enabling constant speed control of the film transmission device 2 while minimizing torque variation during constant speed operation of the AC motor. This torque variation is controlled after the tension deformation control device. The power output from the DC brushless motor 3 is reflected in the film transmission device 2, which consists of a belt wider than the maximum width of the prepreg machine product and small belt loops placed above and on both sides of the belt. All three components are powered by the aforementioned DC motor, with no speed difference between them. During operation, the lower belt surface is 50mm above the prepreg composite plane, and the film is clamped by the two belts to achieve constant-speed paper feeding. The film transmission belt has a high-friction coefficient rubber outer surface, and the small belts on both sides have irregular bumps to prevent stress concentration during paper feeding. The belt length is 300mm. Force sensor 5 is used to measure the change in horizontal force at the position of the paper feed roller in the film transmission device 2. After analysis, this force signal is applied to the damping torque device 4 (described later) and the constant speed adjustment of the aforementioned brushless DC motor 3. Considering the possible slippage between this device and the film, adjusting the speed of the damping torque device 4 and this device can ensure that the film shrinks before entering the lamination process. The damping torque device 4 is composed of an adjustable linear spring, which can be improved to an electromagnetic spring. In the existing prepreg production process, there are changes in the shaft torque due to changes in the radius of the yarn beam and the conveyor roller, as well as changes in the working principle of the AC motor. The damping torque device 4 should adjust the damping based on the frequency of change fed back by the force sensor 5. After the film is output via belt, it is monitored on-site by the wavy material platform 601 and multiple point light sources 602 in the vision inspection device 6. The end of the material platform is aligned with the prepreg production plane. The wavy material platform has a sinusoidal waveform with a frequency decreasing along the direction of prepreg travel. During production, the tension of the film 1 is observed based on the scattered halo generated by the point light sources 602 as they pass through the film, facilitating equipment monitoring and manual adjustment by production personnel. Table 1 shows information for the comparative example and the embodiment.

[0045] Table 1

[0046] Comparative example Example 1 Example 2 Enhance fiber modulus 255GPa 240GPa 255GPa Release paper modulus 8.4 GPa 7.8 GPa 8.4 GPa Deformation difference <![CDATA[4cm 2 / 100m 2 ]]> <![CDATA[0.47cm 2 / 100m 2 ]]> <![CDATA[0.94cm 2 / 100m 2 ]]> Product roll length 94 88 95

[0047] Unidirectional carbon fiber prepreg Model 1203 / GW700S / 38 is a product urgently needed by the domestic general aviation industry, meeting the verification requirements of the Civil Aviation Administration of China's Airworthiness Certification Center. Currently, imported prepregs are commonly used in the manufacture of general aviation aircraft. Because this product can be used in automated prepreg application, customers have requested higher single-roll lengths. However, existing equipment exhibits bubbling defects due to tension deformation during production, with an average bubbling defect size of 1.3cm.2 / 100m 2 This device is now used to produce a 1000mm wide T700 grade carbon fiber medium-temperature cured epoxy resin unidirectional tape prepreg. The product surface is free of blistering, and no wrinkles appear after refrigeration after winding. The prepreg product is of high quality, with a 100m width... 2 Product bubbling or wrinkling defects <0.5cm 2 Due to the product standard requirements for prepregs, the reduction in product defects significantly reduces problems in subsequent shredding and tape cutting processes and automated material laying, saving on the difficulty and risks of subsequent processes, greatly reducing costs, improving production efficiency, and effectively saving time and labor.

[0048] In addition, the use of this device during the production of a certain 1000mm wide T700 grade medium-temperature curing epoxy resin unidirectional tape prepreg has also improved the surface bubbling and wrinkling issues during winding. 2 The product's bubbling or wrinkling defects are approximately 4cm from the original product. 2 Optimized to <1cm 2 This surpasses the standard requirements for prepreg products. Furthermore, the reduction in product defects significantly decreases problems in subsequent shredding and tape cutting processes and automated material laying, reducing the difficulty and risk of subsequent processes, resulting in substantial cost reduction, improved production efficiency, and effective savings in time and labor.

[0049] During operation, firstly, during prepreg production, the film 1 is passed through the film transmission device 2 of this device before entering the laminating process. The film transmission device 2 is adjusted to clamp both sides of the film 1. Then, the DC brushless motor 3 is turned on, and the prepreg machine is started. The DC brushless motor 3 is adjusted to the fixed linear speed of prepreg production. First, the damping torque device 4 is adjusted according to the frequency of the force sensor 5 reading. After the force sensor reading amplitude drops below 10N, the servo motor speed is adjusted according to the force sensor 5 reading. The DC brushless motor 3 speed should be slightly higher than the prepreg production speed. The speed adjustment endpoint is when the force sensor reading is within the range of 0±10N.

[0050] After the equipment adjustment is completed, observe whether the film 1 moves forward along the wavy platform on the visual inspection device 6. The manifestation of the prepreg releasing tension deformation is that the prepreg moves along the surface of the wavy platform. The halo produced by the point light source on the wavy platform illuminating the film is small.

[0051] Through the above process, the radial deformation of the adhesive film caused by tension during the paper feeding and lamination process is completely shrunk, realizing zero deformation difference between the adhesive film and the reinforcing material. This solves the problem of wrinkling or bubbling in the coding of prepreg products and improves the quality level of raw materials for subsequent composite material production processes.

[0052] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. The present invention is not limited to the specific steps and structures described above and shown in the figures. Furthermore, for the sake of brevity, detailed descriptions of known methods and techniques are omitted here.

[0053] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art without departing from the scope of the invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. A two-step prepreg machine film tension deformation control device, characterized in that, It includes a film transmission device (2), a DC brushless motor (3), a damping torque device (4), a force sensor (5), and a vision inspection device (6); among which, The film transmission device (2) is used to drive the film (1) to move. The DC brushless motor (3) is connected to the film transmission device (2) and is used to drive the conveyor belt of the film transmission device (2) to rotate. The force sensor (5) is connected to the DC brushless motor (3) and the damping torque device (4) in sequence and is used to analyze and transmit the measured change signal of the horizontal force at the position of the paper feed roller in the film transmission device (2) to the DC brushless motor (3) and the damping torque device (4). The damping torque device (4) is used to adjust the damping of the film (1). The visual inspection device (6) is located at the outlet end of the film transmission device (2) and is used to monitor the tension of the film (1); The film transmission device (2) includes a lower conveyor belt (202) wider than the maximum width of the prepreg product and an upper conveyor belt (201) placed above both sides of the lower conveyor belt (202). The distance between the two upper conveyor belts (201) is less than the maximum width of the prepreg product. The upper conveyor belt (201) is provided with irregular concave and convex portions, which are used to avoid stress concentration during the paper feeding process.

2. The two-step prepreg machine film tension deformation control device according to claim 1, characterized in that, The outer surfaces of the upper conveyor belt (201) and / or the lower conveyor belt (202) are rubber surfaces with a high coefficient of friction.

3. The two-step prepreg film tension deformation control device according to claim 1, characterized in that, The damping torque device (4) is an adjustable linear spring or an electromagnetic spring.

4. The two-step prepreg machine film tension deformation control device according to claim 1, characterized in that, The visual inspection device (6) includes a material platform (601) and a plurality of point light sources (602) disposed on the material platform. The end of the material platform (601) is connected to the prepreg production plane.

5. The two-step prepreg film tension deformation control device according to claim 4, characterized in that, The upper surface of the material platform (601) is a plurality of smooth curved surfaces connected in sequence, and the extension direction of the smooth curved surfaces is parallel to the travel direction of the prepreg.

6. The two-step prepreg film tension deformation control device according to claim 5, characterized in that, The smooth surface is a sinusoidal waveform surface.

7. The two-step prepreg machine film tension deformation control device according to claim 6, characterized in that, The frequency of the sinusoidal waveform surface decreases sequentially along the direction of travel of the prepreg.

8. The two-step prepreg film tension deformation control device according to claim 1, characterized in that, The brushless DC motor (3) is a brushless DC servo motor and is controlled by a microcontroller.

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