Auxiliary automatic discharging method for thermoplastic prepreg

Abstract

The invention discloses a thermoplastic prepreg auxiliary automatic blanking method, and belongs to the technical field of thermoplastic composite materials. The automatic blanking method comprises the following steps: selecting a target soft film to prepare a prefabricated body according to the binding force characteristic of the thermoplastic prepreg; the prefabricated body is adsorbed to a table top of an automatic discharging machine, a preset program is input for automatic discharging, and a discharging piece is obtained; the soft mold on the surface of the blanking sheet is removed, and a blanking sheet corresponding to the target shape is obtained; the target shape is a preset shape on the automatic blanking machine. By means of the method, the problem that automatic discharging cannot be achieved due to the defects that in the prior art, thermoplastic prepreg is poor in quality, low in surface flatness and the like can be solved.

Description

Technical Field

[0001] This application belongs to the technical field of thermoplastic composites, and specifically relates to a method for automatically cutting thermoplastic prepregs assisted by a soft film. Background Art

[0002] Prepreg, commonly known as molding compound, is a composite made by impregnating continuous fibers and their fabrics with resin under strictly controlled conditions. It is an intermediate for manufacturing composites and can be divided into thermosetting prepregs and thermoplastic prepregs according to the type of resin selected.

[0003] In China, the research and development of thermoplastic prepregs started relatively late, resulting in problems such as immature preparation processes and poor preparation quality in existing thermoplastic prepregs. Specifically, these problems are reflected in weak interfiber bonding, prepreg warping, and low surface flatness of prepregs. Due to these problems, thermoplastic prepregs cannot be adsorbed on a general automatic cutting machine by negative pressure, so automatic cutting cannot be achieved and only manual cutting can be used, which affects the production efficiency of thermoplastic prepregs.

[0004] Therefore, an improved solution is urgently needed to achieve automatic cutting of thermoplastic prepregs. Summary of the Invention

[0005] The purpose of this application is to provide a method for automatically cutting thermoplastic prepregs assisted by a soft film, which can solve problems such as weak interfiber bonding, prepreg curling, and low surface flatness of thermoplastic prepregs in the prior art, so as to achieve the purpose of automatic cutting.

[0006] To achieve the above purpose, this application provides a method for automatically cutting thermoplastic prepregs assisted by a soft film, including the following steps: According to the bonding property of the thermoplastic prepreg, select a target soft film to prepare a preform; adsorb the preform on the table of the automatic cutting machine, input a predetermined program for automatic cutting to obtain a cut piece; remove the soft film on the surface of the cut piece to obtain a cut piece corresponding to the target shape; the target shape is the shape preset on the automatic cutting machine; The target soft film includes a low-viscosity soft film or a high-viscosity soft film; When the target soft film is a low-viscosity soft film, the preform is a first preform and the cut piece is a first cut piece; When the target soft film is a high-viscosity soft film, the preform is a first preform and the cut piece is a first cut piece.

[0007] Preferably, the method for determining the bonding property of the thermoplastic prepreg includes: When the bonding force of the thermoplastic prepreg is greater than a preset threshold, it is determined that the bonding property of the thermoplastic prepreg is strong; When the bonding force of the thermoplastic prepreg is less than or equal to the preset threshold value, it is determined that the bonding force characteristic of the thermoplastic prepreg is weak.

[0008] Among them, the preset threshold value for determining the bonding force of the thermoplastic prepreg is: the threshold value for determining the bonding force of the thermoplastic prepreg is that, when observed by the light transmission method in the natural state, there are no gaps or crevices that can be identified by the naked eye between the fiber tows, and when a force of 5 N is applied perpendicular to both sides of the fiber, the prepreg does not undergo damage such as tearing.

[0009] Preferably, the steps of selecting a target soft film to prepare a preform according to the bonding force characteristic of the thermoplastic prepreg include: When the bonding force characteristic of the thermoplastic prepreg is strong, the single-sided adhesive low-viscosity soft film is respectively pasted on the upper surface and the lower surface of the thermoplastic prepreg to obtain the first preform.

[0010] Preferably, the thickness of the low-viscosity soft film is 0.4 mm to 0.6 mm, and the viscosity of the low-viscosity soft film ≤ 0.1 kg / 25 mm.

[0011] Preferably, the steps of selecting a target soft film to prepare a preform according to the bonding force characteristic of the thermoplastic prepreg include: When the bonding force characteristic of the thermoplastic prepreg is weak, the single-sided adhesive high-viscosity soft film is pasted on one side of the thermoplastic prepreg to obtain the second preform.

[0012] Preferably, the thickness of the high-viscosity soft film is 0.4 mm to 0.6 mm, and the viscosity of the high-viscosity soft film ≥ 0.2 kg / 25 mm.

[0013] Preferably, the steps of adsorbing the preform on the automatic blanking machine table and inputting a predetermined program for automatic blanking include: For the first preform, place the first preform on the automatic blanking machine, turn on the vacuum pumping system so that the first preform is stably adsorbed on the automatic blanking machine table, and input a predetermined program for automatic blanking; For the second preform, place the second preform on the automatic blanking machine, face the side of the second preform with the soft film towards the vacuum adsorption surface, turn on the vacuum pumping system so that the second preform is stably adsorbed on the automatic blanking machine table, and input a predetermined program for automatic blanking.

[0014] Preferably, the steps of removing the soft film on the surface of the blanking sheet to obtain a blanking sheet corresponding to the target shape include: For the first blanking sheet, manually tear off the upper surface soft film and the lower surface soft film of the first blanking sheet to obtain a blanking sheet corresponding to the target shape; For the second blanking sheet, with the assistance of a heating device, manually tear off the soft mold on the upper surface of the second blanking sheet to obtain a blanking sheet corresponding to the target shape.

[0015] Preferably, it further includes: after removing the soft mold of the first blanking sheet, there is no glue residue on the surface of the obtained blanking sheet.

[0016] Preferably, it further includes: after removing the soft mold of the second blanking sheet, use a solvent to remove the residual glue on the surface of the blanking sheet.

[0017] In summary, the present application has the following advantages: The thermoplastic prepreg assisted automatic blanking method provided by the present application prepares a preform by using a low-viscosity or high-viscosity soft mold, then uses vacuum adsorption technology to achieve stable fixation, and finally removes the soft mold by manual tearing, effectively solving technical problems such as weak bonding force between thermoplastic prepreg filaments, prepreg curling, and low surface flatness.

[0018] The method can automatically select the type and thickness of the soft mold according to the bonding force characteristics of the prepreg, ensuring that the surface of the preform is flat and has good vacuum adsorption performance. And the automatic blanking process is accurate and efficient, and the obtained blanking sheet can be directly used for subsequent forming processes. For different preforms, the soft mold is removed by manual tearing or heating-assisted tearing respectively, ensuring the complete removal of the soft mold without leaving residual glue and guaranteeing the surface quality of the blanking sheet.

[0019] The method is simple, easy to operate, has good versatility and economy, significantly improves the efficiency and quality of thermoplastic prepreg automatic blanking, and promotes the progress of thermoplastic composite material automatic production technology. Brief Description of the Drawings

[0020] Figure 1 is a schematic flow chart of the thermoplastic prepreg assisted automatic blanking method of the present application; Figure 2 is a schematic structural diagram of the first preform in Embodiment 1; Figure 3 is a schematic diagram of blanking by an automatic blanking machine in Embodiment 1; Figure 4 is a flow chart of tearing off a low-viscosity soft mold to obtain blanking sheet A in Embodiment 1 Figure 5 is a schematic structural diagram of the second preform in Embodiment 2; Figure 6 is a schematic diagram of blanking by an automatic blanking machine in Embodiment 2; Figure 7 is a flow chart of tearing off a high-viscosity soft mold to obtain blanking sheet B in Embodiment 2; Among them, 1. Low-viscosity soft mold; 2. Strong thermoplastic prepreg; 3. First preform; 4. Automatic cutting knife; 5. First cutting piece; 6. Cutting piece A; 7. High-viscosity soft mold; 8. Weak thermoplastic prepreg; 9. Second preform; 10. Hot air blower; 11. Second cutting piece; 12. Cutting piece B. Specific embodiments

[0021] The principles and features of the present application will be described below in conjunction with embodiments. The examples given are only for explaining the present application and are not intended to limit the scope of the present application. For those conditions not specified in the embodiments, they shall be carried out according to the conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments whose manufacturers are not indicated, they are all conventional products that can be obtained through commercial purchase.

[0022] A prepreg refers to a semi-finished product strip or sheet with a uniform thickness formed by impregnating a resin matrix on reinforcing fibers in a certain manner. It is an intermediate product in the transition of composite materials from raw materials to products. A prepreg generally includes a matrix resin and reinforcing fibers. Thermoplastic prepregs are usually cut by hand, relying on manual cutting of prepregs, which has disadvantages such as slow speed and high labor intensity, and it is difficult to meet the requirements of large-scale and batch production. At the same time, manual cutting is also difficult to ensure dimensional accuracy and edge quality, and errors and burrs are likely to occur, affecting the subsequent forming quality and product performance. An automatic cutting machine can quickly and accurately cut prepreg parts with complex shapes, which can greatly improve production efficiency and shorten the production cycle. And the automatic cutting machine can perform precise cutting according to a preset program, so as to ensure that the size and shape of each part are consistent, and improve the stability and reliability of product quality.

[0023] Therefore, an important measure to promote the development of the thermoplastic composite material industry is to realize the automatic cutting of domestic thermoplastic prepregs. Automatic cutting can improve production efficiency, product quality and consistency, and can reduce production costs, which not only promotes the popularization and application of thermoplastic composite materials, but also enhances the competitiveness of domestic materials. Through automated production, it can better meet the needs of the high-end equipment manufacturing field for high-performance and lightweight materials, and promote the transformation and upgrading of China's manufacturing industry. However, due to the short R & D time of domestic thermoplastic prepregs, there are problems such as weak bonding force between prepreg tows, prepreg warping and low surface flatness of prepregs, resulting in that the thermoplastic prepregs cannot be adsorbed on a general automatic cutting machine by vacuum negative pressure, and thus automatic cutting cannot be realized.

[0024] Based on this, as Figure 1 shown, the present application provides a method for assisting automatic cutting of thermoplastic prepregs, including the following steps: S1. According to the bonding force characteristics of the thermoplastic prepreg, select a target soft mold to prepare a preform; S2. Adsorb the preform on the tabletop of the automatic blanking machine, input a predetermined program for automatic blanking, and obtain a blanking sheet. S3. Remove the soft mold on the surface of the blanking sheet to obtain a blanking sheet corresponding to the target shape; the target shape is the shape preset on the automatic blanking machine. Wherein, the target soft mold includes a low-viscosity soft mold or a high-viscosity soft mold. When the target soft mold is a low-viscosity soft mold, the preform is a first preform, and the blanking sheet is a first blanking sheet. When the target soft mold is a high-viscosity soft mold, the preform is a first preform, and the blanking sheet is a first blanking sheet.

[0025] In this application, two blanking methods for thermoplastic prepregs are provided according to the strength of the self-binding force of the prepreg, which have good versatility. In the overall technical solution, first, by pasting a soft mold on the surface of the prepreg, the defects of insufficient self-binding force and uneven surface can be made up for, so that it can be stably adsorbed on the automatic blanking machine and smoothly cut. Then, through vacuum adsorption and numerical control cutting technologies, precise and efficient cutting of prepreg special-shaped parts is realized to improve production efficiency and accuracy. The blanking method of this application is simple to operate, applicable to most domestic weak and strong thermoplastic prepregs, reduces production costs, and improves economic benefits.

[0026] In this application, the viscosity of the low-viscosity soft mold is ≤0.1 kg / 25 mm, and the viscosity of the high-viscosity soft mold is ≥0.2 kg / 25 mm.

[0027] As an implementable manner of this application, the method for determining the binding force characteristic of the thermoplastic prepreg includes: when the binding force of the thermoplastic prepreg is greater than a preset threshold, it is determined that the binding force characteristic of the thermoplastic prepreg is strong; when the binding force of the thermoplastic prepreg is less than or equal to the preset threshold, it is determined that the binding force characteristic of the thermoplastic prepreg is weak.

[0028] Specifically, the preset threshold for determining the bonding strength of thermoplastic prepreg is as follows: when observed by the light transmission method in the natural state, there are no voids or gaps visible to the naked eye between the fiber bundles, and when a force of 5 N is applied perpendicular to both sides of the fiber, the thermoplastic prepreg does not suffer damage such as tearing. It can be understood that, for example, ① when observed by the light transmission method in the natural state, there are voids or gaps visible to the naked eye between the fiber bundles, and when a force of 5 N is applied perpendicular to both sides of the fiber, the thermoplastic prepreg is torn, indicating that the bonding strength characteristic is weak; ② when observed by the light transmission method in the natural state, there are no voids or gaps visible to the naked eye between the fiber bundles, and when a force of 5 N is applied perpendicular to both sides of the fiber, the thermoplastic prepreg does not suffer damage such as tearing, indicating that the bonding strength characteristic is strong; ③ generally speaking, when observed by the light transmission method in the natural state, there are voids or gaps visible to the naked eye between the fiber bundles, or when a force of 5 N is applied perpendicular to both sides of the fiber, the thermoplastic prepreg is torn, the bonding strength characteristic can also be defined as weak.

[0029] Since the quality of domestic thermoplastic prepregs produced by different manufacturers varies greatly, in this application, the thermoplastic prepregs are classified into strong thermoplastic prepregs and weak thermoplastic prepregs through a unified determination method, which is convenient for management and selection of the blanking method. Among them, the strong thermoplastic prepreg has good self-bonding strength but poor surface flatness; the weak thermoplastic prepreg has poor self-bonding strength and poor surface flatness.

[0030] As an implementable mode of this application, the steps of obtaining a preform by selecting a target soft film according to the bonding strength characteristic of the thermoplastic prepreg include: when the bonding strength characteristic of the thermoplastic prepreg is strong, a single-sided adhesive low-viscosity soft film is respectively pasted on the upper surface and the lower surface of the thermoplastic prepreg to obtain the first preform; when the bonding strength characteristic of the thermoplastic prepreg is weak, a single-sided adhesive high-viscosity soft film is pasted on one side of the thermoplastic prepreg to obtain the second preform.

[0031] This application specifically solves the characteristic problems of different prepregs. According to the actual production requirements, soft films with different viscosities can be flexibly selected to optimize the production process. For strong prepregs with strong self-bonding strength, using a low-viscosity soft film can provide sufficient support and surface protection, and is also convenient for subsequent tearing off, avoiding damage to the surface of the prepreg. And while providing temporary support, the low-viscosity soft film will not overly affect the original characteristics of the prepreg, and can ensure the improvement of surface flatness. For weak prepregs with weak self-bonding strength, which are prone to deformation or delamination, using a high-viscosity soft film can better fix the fibers and resin of the prepreg, prevent it from deforming during handling and cutting, and ensure the stability of the preform. In this application, whether it is a low-viscosity soft film or a high-viscosity soft film, it can ensure the stable adsorption of the preform on the automatic blanking machine, avoiding cutting errors caused by the problems of the prepreg itself.

[0032] As an implementable mode of the present application, to ensure that the surface flatness of the preform can be improved after pasting the soft mold, the thicknesses of both the low-viscosity soft mold and the high-viscosity soft mold are controlled to be 0.4 mm to 0.6 mm. Among them, the thickness of 0.4 mm to 0.6 mm will neither affect the flexibility of the prepreg due to being too thick nor fail to effectively fill the unevenness on the surface of the prepreg due to being too thin, thus ensuring the uniform flatness of the surface of the preform.

[0033] As an implementable mode of the present application, adsorb the preform on the automatic blanking machine table, and input a predetermined program for automatic blanking, including: for the first preform, place the first preform on the automatic blanking machine, turn on the vacuum pumping system so that the first preform is stably adsorbed on the automatic blanking machine table, and input a predetermined program for automatic blanking; for the second preform, place the second preform on the automatic blanking machine, orient the side of the second preform with the soft mold towards the vacuum adsorption surface, turn on the vacuum pumping system so that the second preform is stably adsorbed on the automatic blanking machine table, and input a predetermined program for automatic blanking.

[0034] In the present application, the first preform is a combination of a strong prepreg and a low-viscosity soft mold. Since the strong prepreg itself has good bonding force, it can be stably fixed only by vacuum adsorption. The existence of the low-viscosity soft mold is mainly to improve the surface flatness and protect the surface of the prepreg, preventing the surface of the prepreg from directly contacting the table of the automatic blanking machine during adsorption and cutting, and avoiding damages such as scratches or indentations. The second preform is a combination of a weak prepreg and a high-viscosity soft mold. The weak prepreg has poor bonding force and requires a high-viscosity soft mold to enhance the integrity. Orienting the side with the high-viscosity soft mold towards the vacuum adsorption surface can make full use of the viscosity of the soft mold and the vacuum adsorption force to double-guarantee the stable fixation of the preform, prevent displacement or deformation during cutting, and thus improve the cutting accuracy. The present application stipulates the selection of the adsorption surface and the operation steps for the two preforms respectively, enabling the operator to clearly understand how to operate, avoiding problems such as unstable adsorption or damage to the prepreg caused by improper operation, and improving the reliability and efficiency of the operation.

[0035] As an implementable mode of the present application, remove the soft mold on the surface of the blanking piece to obtain a blanking piece corresponding to the target shape, including: for the first blanking piece, manually tear off the upper surface soft mold and the lower surface soft mold of the first blanking piece to obtain a blanking piece corresponding to the target shape; for the second blanking piece, under the auxiliary action of a heating device, manually tear off the upper surface soft mold of the second blanking piece to obtain a blanking piece corresponding to the target shape. Preferably, the heating device can be a hot air blower, an infrared heater, an electric hot plate, etc.

[0036] In this application, since the first blanking sheet uses a low-viscosity soft mold, the soft mold on the upper and lower surfaces can be easily removed by manual tearing. The operation is simple and will not damage the surface of the prepreg, ensuring the surface quality of the blanking sheet. Since the second blanking sheet uses a high-viscosity soft mold, which is firmly bonded to the prepreg, it may be difficult to directly tear it off or damage the prepreg. The heating device can assist in reducing the viscosity of the soft mold, making the tearing process smoother and avoiding damage to the surface of the prepreg, ensuring the integrity of the blanking sheet.

[0037] As an implementable mode of this application, it further includes: after removing the soft mold of the first blanking sheet, there is no residual glue on the surface of the obtained blanking sheet.

[0038] The first blanking sheet in this application uses a low-viscosity soft mold. After tearing off the soft mold, there is usually no residual glue on the surface of the blanking sheet, ensuring the surface quality of the blanking sheet, enabling it to be directly used in subsequent forming or processing processes without additional cleaning, saving time and cost.

[0039] As an implementable mode of this application, it further includes: after removing the soft mold of the second blanking sheet, the residual glue on the surface of the blanking sheet is removed by means of a solvent. Preferably, the solvent includes acetone, alcohol, etc.

[0040] The second blanking sheet in this application uses a high-viscosity soft mold. After tearing off the soft mold, there may be residual glue on the surface of the blanking sheet. Cleaning with a solvent can effectively remove this residual glue, ensuring the surface quality of the blanking sheet and meeting the requirements of subsequent processes.

[0041] The above technical solutions of this application will be described in detail below in conjunction with specific embodiments.

[0042] Embodiment 1 This embodiment provides a method for automatically blanking assisted by a strong thermoplastic prepreg, as Figures 2 - 4 shown, including the following steps: (1) Stick a single-sided adhesive low-viscosity soft mold 1 on the upper and lower surfaces of the strong thermoplastic prepreg 2 respectively to form a first preform 3; (2) In order to ensure that the surface flatness of the first preform 3 can be improved after the low-viscosity soft mold 1 is pasted, so as to improve the adsorption effect, the thickness of the low-viscosity soft mold 1 is set to 0.5 mm; (3) Place the first preform 3 on an automatic blanking machine, turn on the vacuum adsorption system of the automatic blanking machine, so that the first preform 3 can be completely adsorbed on the tabletop of the automatic blanking machine, input a predetermined program, and use an automatic blanking knife 4 to perform automatic blanking to obtain a first blanking sheet 5; After the blanking is completed, take out the first blanking sheet 5, and manually tear off the low-viscosity soft mold 1 pasted on the upper and lower surfaces of the first blanking sheet 5 to obtain the blanking sheet A 6 corresponding to the target shape without residual glue on the surface.

[0043] Embodiment 2 This embodiment provides a method for automatically blanking assisted by a weak thermoplastic prepreg. As Figures 5 - 7 shown, it includes the following steps: (1) Paste a single-sided adhesive high-viscosity soft mold 7 on the upper surface of the weak thermoplastic prepreg 8 to form a second preform 9; (2) In order to ensure that the surface flatness of the second preform 9 can be improved after the high-viscosity soft mold 7 is pasted, so as to improve the adsorption effect, the thickness of the high-viscosity soft mold 7 is set to 0.5 mm; (3) Place the second preform 9 on an automatic blanking machine, turn on the vacuum adsorption system of the automatic blanking machine, so that the second preform 9 can be completely adsorbed on the table of the automatic blanking machine, input a predetermined program, and use the automatic blanking knife 4 for automatic blanking to obtain the second blanking sheet 11; (4) After the blanking is completed, take out the second blanking sheet 11, and manually and slowly tear off the high-viscosity soft mold 7 on the upper surface of the second blanking sheet 11 with the assistance of a hot air blower 10. Since there is usually a small amount of resin remaining on the surface of the second blanking sheet 11 for the high-viscosity soft mold 7, it is also necessary to use solvents such as acetone or alcohol to remove the residual glue on the surface completely, so as to avoid forming inclusions remaining on the surface of the second blanking sheet 11, and then obtain the blanking sheet B 12 corresponding to the target shape without residual glue on the surface.

[0044] In summary, the present application specifically solves the problems encountered in the automatic blanking process of strong thermoplastic prepregs and weak thermoplastic prepregs, improves the surface flatness and stability of the preform, ensures the efficiency and accuracy of automatic blanking, and has significant practical value and economic benefits.

[0045] (1) For strong prepregs, through the synergistic effect of soft mold-vacuum-numerical control cutting, the rapid conversion of thermoplastic prepregs from continuous sheets to precise shaped parts is realized. The high-viscosity soft mold is not only a protective layer in the processing process, but also a key carrier connecting cutting and subsequent forming processes, significantly improving the manufacturing efficiency and finished product rate of composite components. Specifically: 1) First, protect and position with a low-viscosity soft mold: Thermoplastic prepregs are prone to deformation or surface damage during processing. A low-viscosity soft mold (such as a polyethylene or silicone film) is pasted on the upper and lower surfaces of the prepreg through a single-sided adhesive, playing a role of temporary support, surface protection, and shaping. The flexibility of the low-viscosity soft mold can adapt to the initial shape of the flexible prepreg, and at the same time, the low-viscosity characteristic ensures that it can be torn off without damage subsequently. The low-viscosity soft mold also serves as an auxiliary positioning layer, closely fitting with the flexible prepreg during vacuum pumping to form a flat composite structure, avoiding the displacement of the flexible prepreg during adsorption or cutting.

[0046] 2) Then, achieve stability through vacuum adsorption: The vacuum system of the automatic cutting machine adsorbs the preform (prepreg + soft mold) on the surface of the workbench through negative pressure, ensuring that the material remains rigidly fixed during high-speed cutting, preventing cutting errors caused by vibration or warping. The uniform distribution of the vacuum adsorption force can also avoid damaging the material due to local stress concentration.

[0047] 3) Finally, control the accuracy through numerical control cutting: The automatic cutting machine (such as a numerically controlled knife cutter or a laser cutting machine) cuts the material in layers according to the preset program path, using a high-speed rotating tool or a laser beam. The presence of the low-viscosity soft mold not only protects the prepreg from direct tool impact but also reduces the cutting resistance through its low-friction surface, prolonging the tool life.

[0048] (2) For flexible prepregs, by utilizing the strengthening and protecting effect of a high-viscosity soft mold, combined with the stable fixing technology of vacuum adsorption and the soft mold tearing method assisted by heating, precise cutting of thermoplastic prepregs with poor bonding strength is achieved. Specifically: 1) First, assist in strengthening and protecting with a high-viscosity soft mold: For thermoplastic prepregs with poor bonding strength, by pasting a single-sided adhesive high-viscosity soft mold on one of its surfaces, the integrity and bonding strength of the preform can be significantly improved. The high-viscosity soft mold wraps the surface of the flexible prepreg, preventing delamination or deformation during handling and processing. At the same time, the smooth and flat surface provided by the high-viscosity soft mold also makes up for the possible surface defects of the flexible prepreg itself, making it more suitable for vacuum adsorption and automatic cutting.

[0049] 2) Then, achieve stable fixing through vacuum adsorption: Place the flexible preform on the automatic cutting machine with the soft mold surface facing the vacuum adsorption surface. After turning on the vacuum pumping system, a seal is formed between the high-viscosity soft mold and the vacuum adsorption surface, and the vacuum negative pressure tightly adsorbs the flexible preform on the table, preventing movement or warping during cutting and ensuring cutting accuracy. The presence of the high-viscosity soft mold not only protects the flexible prepreg but also helps to form a good sealing environment, enhancing the effect of vacuum adsorption.

[0050] 3) Finally, the soft mold is removed by heating assistance: The purpose of heating is to reduce the viscosity of the soft mold, making it easier to remove from the surface of the prepreg. Slowly removing the high-viscosity soft mold can avoid damaging the surface of the weak prepreg, and at the same time ensure that the high-viscosity soft mold can be completely removed without leaving residual glue.

[0051] Although the specific implementation manners of the present application have been described in detail, it should not be construed as a limitation on the protection scope of the present application. Within the scope described in the claims, various modifications and deformations that can be made by those skilled in the art without creative efforts still fall within the protection scope of the present application.

Claims

1. A method for automatically cutting a thermoplastic prepreg assisted, characterized in that, It includes the following steps: According to the bonding force characteristics of the thermoplastic prepreg, select a target soft film to prepare a preform; adsorb the preform on the tabletop of an automatic blanking machine, input a predetermined program for automatic blanking to obtain a blanking sheet; remove the soft mold on the surface of the blanking sheet to obtain a blanking sheet corresponding to the target shape; the target shape is the shape preset on the automatic blanking machine; The target soft film includes a low-viscosity soft mold or a high-viscosity soft mold; When the target soft film is a low-viscosity soft mold, the preform is a first preform, and the blanking sheet is a first blanking sheet; When the target soft film is a high-viscosity soft mold, the preform is a first preform, and the blanking sheet is a first blanking sheet.

2. The method according to claim 1, characterized in that, The method for determining the bonding force characteristics of the thermoplastic prepreg includes: When the bonding force of the thermoplastic prepreg is greater than a preset threshold, it is determined that the bonding force characteristic of the thermoplastic prepreg is strong; When the bonding force of the thermoplastic prepreg is less than or equal to the preset threshold, it is determined that the bonding force characteristic of the thermoplastic prepreg is weak; Wherein, the judgment criterion for the preset threshold is: apply a 5N force perpendicular to both sides of the fiber, and the thermoplastic prepreg does not tear.

3. The method according to claim 2, wherein The step of selecting a target soft film to prepare a preform according to the bonding force characteristics of the thermoplastic prepreg includes: When the bonding force characteristic of the thermoplastic prepreg is strong, paste the single-sided adhesive low-viscosity soft mold on the upper surface and the lower surface of the thermoplastic prepreg respectively to obtain the first preform.

4. The method according to claim 3, characterized in that, The thickness of the low-viscosity soft mold is 0.4mm - 0.6mm, and the viscosity of the low-viscosity soft mold ≤ 0.1kg / 25mm.

5. The method according to claim 2, wherein The step of selecting a target soft film to prepare a preform according to the bonding force characteristics of the thermoplastic prepreg includes: When the bonding force characteristic of the thermoplastic prepreg is weak, paste the single-sided adhesive high-viscosity soft mold on one side of the thermoplastic prepreg to obtain the second preform.

6. The method according to claim 5, characterized in that, The thickness of the high-viscosity soft mold is 0.4mm - 0.6mm, and the viscosity of the high-viscosity soft mold ≥ 0.2kg / 25mm.

7. The method according to claim 1, wherein The step of adsorbing the preform on the tabletop of the automatic blanking machine and inputting a predetermined program for automatic blanking includes: For the first preform, place the first preform on the automatic blanking machine, turn on the vacuum pumping system to stably adsorb the first preform on the tabletop of the automatic blanking machine, and input a predetermined program for automatic blanking; For the second preform, place the second preform on the automatic blanking machine, orient the side of the second preform with the soft mold towards the vacuum adsorption surface, turn on the vacuum pumping system to stably adsorb the second preform on the tabletop of the automatic blanking machine, and input a predetermined program for automatic blanking.

8. The method according to claim 1, wherein The step of removing the soft mold on the surface of the blanking sheet to obtain a blanking sheet corresponding to the target shape includes: For the first blanking sheet, manually tear off the upper surface soft mold and the lower surface soft mold of the first blanking sheet to obtain a blanking sheet corresponding to the target shape; For the second blanking sheet, manually tear off the upper surface soft mold of the second blanking sheet with the assistance of a heating device to obtain a blanking sheet corresponding to the target shape.

9. The method according to claim 8, wherein It also includes: After removing the soft mold of the first blanking sheet, the surface of the obtained blanking sheet has no residual glue.

10. The method according to claim 8, wherein It further includes: After removing the soft mold of the second blanking sheet, the residual glue on the surface of the blanking sheet is removed by means of a solvent.

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