A surface treatment method for thermoplastic composite material automatic placement molding mold

Abstract

The present invention discloses a surface treatment method for an automatic placement molding mold of a thermoplastic composite material, wherein a polyimide fluid is applied to a surface treatment groove of a self-heating and cooling mold; a coating positive mold is attached to a self-heating and cooling mold, and a polyimide fluid is covered on a second coating surface of the self-heating and cooling mold to form a polyimide coating; after passing through a laying channel, a thermoplastic prepreg is attached to the polyimide coating on the surface of the self-heating and cooling mold, and the thermoplastic prepreg and the polyimide coating are melted and combined under the irradiation of a light spot. In the present invention, a polyimide coating is formed on the surface of the self-heating and cooling mold, and the self-heating and cooling mold is heated. Heat is transferred to the polyimide coating by heat conduction, resulting in an increase in the viscosity of the polyimide coating. During the laying process, a stronger bonding interface can be formed with the laying prepreg. After the laying is completed, the viscosity of the polyimide coating is adjusted by adjusting the temperature of the self-heating and cooling mold, and sampling is convenient.

Description

Technical Field

[0001] The invention belongs to the field of thermoplastic composite material molding, and in particular relates to a surface treatment method for a thermoplastic composite material automatic placement molding die. Background Art

[0002] Fiber-reinforced thermoplastic composites have excellent properties such as good toughness and damage tolerance, and are widely used in aerospace, rail transportation, and sporting goods. Common high-performance thermoplastic composite molding methods include traditional compression molding and advanced manufacturing technology fiber automatic placement molding. Automatic placement molding has become the most promising advanced manufacturing technology in recent years due to its advantages such as fast, high quality and in-situ molding. However, since the mold surface cannot generate strong van der Waals forces with the thermoplastic matrix during the automatic placement of thermoplastic composites, the adhesion between the automatically placed components and the mold is weak, which eventually leads to the problem that the base of the placed components is separated from the mold surface and cannot be laid further. Therefore, improving the bonding strength between thermoplastic composite components and the mold surface during the automatic placement process is a difficult problem that needs to be solved urgently.

[0003] Existing techniques often use vacuum suction to attach polyimide film to the surface of automated placement molds. This utilizes the principle of like dissolves like to enhance the van der Waals force between the thermoplastic matrix material and the polyimide film on the mold surface, improving bonding strength. However, aerospace components typically have complex shapes, making attaching polyimide film to these surfaces challenging. Furthermore, polyimide film attached to the mold surface is prone to damage during use, resulting in poor economic efficiency. Furthermore, attaching polyimide film during placement can also result in poor sealing, leading to poor placement accuracy. Summary of the Invention

[0004] In order to overcome the problems of poor economy, poor sealing and poor placement accuracy in the existing technology, the purpose of the present invention is to provide a surface treatment method for thermoplastic composite material automatic placement molding molds. This method forms a uniform polyimide coating by melting polyimide powder at high temperature and coating it on the mold surface. The viscosity of the polyimide coating can be dynamically adjusted by self-heating the mold, which can improve the bonding strength between the complex components automatically formed by high-performance thermoplastic composite materials and the mold surface.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A method for surface treatment of a thermoplastic composite material automatic placement molding die comprises the following steps:

[0007] Processing surface treatment grooves on the surface of the self-heating and cooling mold;

[0008] Applying polyimide fluid to the surface treatment groove of the self-heating and cooling mold;

[0009] The coating male mold is attached to the self-heating and cooling mold coated with polyimide fluid, and the polyimide fluid is leveled under pressure and covers the second coating surface of the self-heating and cooling mold to form a polyimide coating with a thickness greater than 1 mm;

[0010] After passing through the laying channel, the thermoplastic prepreg is attached to the polyimide coating on the surface of the self-heating and cooling mold. The thermoplastic prepreg and the polyimide coating are melted and combined under the irradiation of the laser.

[0011] Furthermore, the surface treatment groove is in a rectangular or triangular shape.

[0012] Furthermore, the polyimide fluid is coated on the surface treatment groove of the self-heating cooling mold. The specific process is: spraying high-temperature resistant bonding glue on the surface of the self-heating cooling mold, heating the self-heating cooling mold so that the temperature of the self-heating cooling mold is higher than the melting point of the polyimide fluid, placing the polyimide fluid in the surface treatment groove, and coating it on the surface treatment groove of the self-heating cooling mold after melting.

[0013] Furthermore, the thermoplastic prepreg is arranged on a material roll.

[0014] Furthermore, the thermoplastic prepreg passes through the second guide wheel and the first guide wheel and enters the placement channel.

[0015] Furthermore, the laying channel includes a clamping part, a re-feeding part and a shearing part which are arranged in sequence from top to bottom.

[0016] Furthermore, the clamping part includes a clamping controller, a clamping cylinder, a clamping pressure wheel and a clamping plate. The clamping controller is connected to the clamping cylinder, and the clamping cylinder is connected to the clamping pressure wheel. The clamping controller controls the opening and closing of the clamping cylinder, and the clamping pressure wheel clamps the thermoplastic prepreg on the clamping plate under the push of the clamping cylinder.

[0017] Furthermore, the re-feeding part includes a re-feeding controller, a re-feeding cylinder, a re-feeding shaft and a re-feeding motor. The re-feeding controller is connected to the re-feeding cylinder, and the re-feeding shaft is connected to the re-feeding motor; the re-feeding controller controls the opening and closing of the re-feeding cylinder, and the re-feeding pressure wheel presses the thermoplastic prepreg onto the re-feeding shaft under the push of the re-feeding cylinder, and the re-feeding shaft transports the thermoplastic prepreg downward under the transportation of the re-feeding motor.

[0018] Furthermore, the shearing part includes a shearing controller, a shearing cylinder and a shearing knife. The shearing controller is connected to the shearing cylinder, and the shearing cylinder is connected to the shearing knife. The shearing controller controls the opening and closing of the shearing cylinder. The shearing knife cuts the thermoplastic prepreg in the shearing groove under the push of the shearing cylinder to achieve continuous laying.

[0019] Furthermore, a pressing part is provided below the shearing part, and the pressing part includes a pressing controller, a pressing cylinder and a pressing roller. The pressing controller is connected to the pressing cylinder, which is connected to the pressing roller; the pressing controller is connected to the pressing cylinder, which is connected to the pressing roller; the pressing controller controls the opening and closing of the pressing cylinder, and the pressing roller, pushed by the pressing cylinder, adheres the thermoplastic prepreg to the polyimide coating on the surface of the self-heating and cooling mold.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention forms a polyimide coating with a thickness of at least 1 mm on the surface of a self-heating and cooling mold. At the same time, by heating the self-heating and cooling mold, heat is transferred to the polyimide coating by heat conduction, resulting in an increase in the viscosity of the polyimide coating. Therefore, during the laying process, a stronger bonding interface can be formed with the laid prepreg. After the laying is completed, the viscosity of the polyimide coating can be adjusted by adjusting the temperature of the self-heating and cooling mold to achieve the purpose of convenient sampling. Since the present invention forms a uniform polyimide coating on the surface of the steel mold, there is no problem of slippage between the coating and the surface of the steel mold, which ensures the laying accuracy and solves the problem of poor laying accuracy; by adjusting the temperature of the steel mold to adjust the viscosity of the polyimide coating, the phenomenon of damage and adhesion of the polyimide coating can be effectively reduced, solving the problem of damage and adhesion of the polyimide film on the surface of the molded component; the present invention improves economy and reduces time cost, improves the problem of poor sealing between the polyimide and the steel mold surface, and is suitable for simple and complex shape components. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the overall schematic diagram of automatic placement molding of thermoplastic composite materials;

[0023] Figure 2 Schematic diagram of surface roughening for automated placement of thermoplastic composite materials;

[0024] Figure 3 Schematic diagram of the surface coating treatment of the automatic placement mold;

[0025] Figure 4 This is a schematic diagram of the automatic placement molding die after processing;

[0026] Figure 5 This is a photo of the steel mold surface.

[0027] In the figure: 1 is a self-heating and cooling mold, 2 is a polyimide coating, 3 is an automatic placement of thermoplastic composite materials, 4 is a pressure roller, 5 is a pressing cylinder, 6 is a shearing controller, 7 is a shearing cylinder, 8 is a re-feeding controller, 9 is a re-feeding cylinder, 10 is a clamping controller, 11 is a clamping cylinder, 12 is a first guide wheel, 13 is a second guide wheel, 14 is a material reel, 15 is a thermoplastic prepreg, 16 is a clamping pressure wheel, 17 is a clamping plate, 18 is a re-feeding pressure wheel, 19 is a re-feeding motor, 20 is a re-feeding shaft, 21 is a shearing groove, 22 is a shearing knife, 23 is a pressing controller, 24 is a laser, 25 is a pyrometer, 26 is a surface treatment tank for the self-heating and cooling mold, 27 is a polyimide fluid, 28 is a coating positive mold, 29 is a first coating surface, and 30 is a second coating surface. DETAILED DESCRIPTION

[0028] The present invention is described in detail below with reference to the accompanying drawings.

[0029] See also Figure 1 、 Figure 2 、 Figure 3 and Figure 4 The present invention provides a surface treatment method for a thermoplastic composite material automatic placement molding die, comprising the following steps:

[0030] First, a surface treatment groove 26 is machined on the surface of the self-heating and cooling mold 1. The shape of the surface treatment groove 26 is not specified and can be a woven rectangle or triangle. The purpose is to increase the surface roughness of the mold, increase the contact area with the polyimide fluid 27, and increase the bonding strength between the coating and the mold surface.

[0031] Then, a high-temperature resistant bonding adhesive (with a heat-resistant temperature greater than 500° C.) is sprayed on the surface of the self-heating and cooling mold 1, and the temperature of the self-heating and cooling mold 1 is heated to be higher than the melting point of the polyimide fluid 27. The polyimide fluid 27 is placed in a surface treatment tank 26, melted, and coated on the surface treatment tank 26 of the self-heating and cooling mold 1;

[0032] Secondly, a high-temperature resistant mold release agent (with a heat-resistant temperature greater than 500°C, such as a JD series high-temperature resistant mold release agent) is sprayed on the first coating surface 29 of the coating male mold 28. The coating male mold 28 is attached to the self-heating and cooling mold 1 coated with the polyimide fluid 27 by closing the mold. The polyimide fluid 27 is leveled under pressure and covers the second coating surface 30 of the self-heating and cooling mold 1 (the second coating surface 30 is the surface of the surface treatment tank), forming a uniform polyimide coating 2 with a thickness greater than 1 mm.

[0033] In the present invention, the first coating surface 29 of the coating male mold 28 is utilized to self-heat and cool the second coating surface 30 of the mold 1 .

[0034] Finally, the high-performance thermoplastic composite material is placed using automated placement equipment. The thermoplastic prepreg 15 on the material roll 14 passes through the second guide wheel 13 and the first guide wheel 12 and enters the placement channel.

[0035] The placement channel includes a clamping section, a re-feeding section, and a shearing section arranged in sequence from top to bottom. Specifically, the clamping section includes a clamping controller 10, a clamping cylinder 11, a clamping roller 16, and a clamping plate 17. The clamping controller 10 is connected to the clamping cylinder 11, which is in turn connected to the clamping roller 16. The clamping controller 10 controls the opening and closing of the clamping cylinder 11. The clamping roller 16, driven by the clamping cylinder 11, clamps the thermoplastic prepreg 15 on the clamping plate 17.

[0036] The re-feeding part includes a re-feeding controller 8, a re-feeding cylinder 9, a re-feeding shaft 20 and a re-feeding motor 19. The re-feeding controller 8 is connected to the re-feeding cylinder 9, and the re-feeding shaft 20 is connected to the re-feeding motor 19. The re-feeding controller 8 controls the opening and closing of the re-feeding cylinder 9. The re-feeding pressure wheel 18 presses the thermoplastic prepreg 15 onto the re-feeding shaft 20 under the push of the re-feeding cylinder 9. The re-feeding shaft 20 conveys the thermoplastic prepreg 15 downward under the conveyance of the re-feeding motor 19.

[0037] The shearing part includes a shearing controller 6, a shearing cylinder 7 and a shearing knife 22. The shearing controller 6 is connected to the shearing cylinder 7, and the shearing cylinder 7 is connected to the shearing knife 22. The shearing controller 6 controls the opening and closing of the shearing cylinder 7. The shearing knife 22 cuts the thermoplastic prepreg 15 in the shearing groove under the push of the shearing cylinder 7 to achieve continuous laying.

[0038] A pressing section is located below the shearing section. The pressing section includes a pressing controller 23, a pressing cylinder 5, and a pressing roller 4. The controller 23 is connected to the pressing cylinder 5, which in turn is connected to the pressing roller 4. The pressing controller 23 controls the opening and closing of the pressing cylinder 5. Driven by the pressing cylinder 5, the pressing roller 4 adheres the thermoplastic prepreg 15 to the polyimide coating 2 on the surface of the self-heating and cooling mold 1. The thermoplastic prepreg 15 and the polyimide coating 2 fuse and bond under the irradiation of the laser 24. A pyrometer 25 measures the laser spot temperature.

[0039] The self-heating and cooling mold 1 can control the temperature of the polyimide coating 2 to be adjusted within the range of 25° C.-400° C., thereby dynamically regulating the bonding strength between the polyimide coating 2 and the thermoplastic prepreg 15 .

[0040] When the polyimide coating 2 is damaged, it can be repaired by the above-mentioned polyimide coating 2 plating method.

[0041] The invention has the advantages of adjustable bonding strength, reusability and surface repairability.

[0042] See also Figure 2 It can be seen that by adding the treatment groove 26 on the surface of the self-heating and cooling mold 1, the contact area between the coating and the steel mold is increased, thereby improving the bonding strength.

[0043] See also Figure 3 It can be seen that by melting polyimide at high temperature, the polyimide melt can be evenly coated on the surface of the steel mold.

[0044] See also Figure 4 It can be seen that through the above process method, a stable and uniform polyimide coating can be formed on the surface of the steel mold.

[0045] See also Figure 5 It can be seen that a uniform polyimide coating is formed on the surface of the steel mold, and experiments have shown that the present invention can increase the adhesion between the prepreg and the mold surface from approximately 3N to 5N (6.35mm prepreg peeling force), which is nearly doubled.

[0046] Compared with the prior art, the present invention forms a polyimide coating with a thickness of at least 1 mm on the surface of the steel mold. At the same time, by heating the steel mold, the heat is transferred to the polyimide coating through heat conduction, resulting in an increase in the viscosity of the polyimide coating. Therefore, during the placement process, a stronger bonding interface can be formed with the prepreg to be placed. After the placement is completed, the viscosity of the polyimide coating can be adjusted by adjusting the temperature of the steel mold, thereby achieving the purpose of convenient sampling. The present invention mainly overcomes the following technical problems: First, it solves the problem of poor placement accuracy. Since a uniform polyimide coating is formed on the surface of the steel mold, there is no problem of slippage between the coating and the steel mold surface, ensuring placement accuracy; second, it solves the problem of polyimide film damage and adhesion to the surface of the molded component. By adjusting the temperature of the steel mold to adjust the viscosity of the polyimide coating, the phenomenon of polyimide coating damage and adhesion can be effectively reduced; third, it improves economic efficiency and reduces time cost; fourth, it solves the problem of poor sealing between the polyimide and the steel mold surface; fifth, the solution proposed by the present invention is applicable to components with simple and complex shapes.

Claims

1. A thermoplastic composite material automatic placement molding method, characterized in that: The following steps are involved: A surface treatment groove (26) is machined on the surface of the self-heating and cooling mold (1); Applying a polyimide fluid (27) to a surface treatment groove (26) of a self-heating and cooling mold (1); The coating positive mold (28) is attached to the self-heating and cooling mold (1) coated with the polyimide fluid (27), and the polyimide fluid (27) is leveled under pressure and covers the second coating surface (30) of the self-heating and cooling mold (1), forming a polyimide coating (2) with a thickness greater than 1 mm. After passing through the laying channel, the thermoplastic prepreg is attached to the polyimide coating (2) on the surface of the self-heating and cooling mold (1). The thermoplastic prepreg (15) is melted under the irradiation of the laser (24) and then combined with the polyimide coating (2).

2. The method for automatic placement and molding of thermoplastic composite materials according to claim 1, characterized in that: The surface treatment groove (26) is in the shape of a rectangle or a triangle.

3. The method for automatic placement of thermoplastic composite materials according to claim 1, characterized in that: The polyimide fluid (27) is coated on the surface treatment groove (26) of the self-heating and cooling mold (1). The specific process is: spraying high-temperature resistant bonding glue on the surface of the self-heating and cooling mold (1), heating the self-heating and cooling mold (1) so that the temperature is higher than the melting point of the polyimide fluid (27), placing the polyimide fluid (27) in the surface treatment groove (26), and coating the polyimide fluid (27) on the surface treatment groove (26) of the self-heating and cooling mold (1) after it is melted.

4. The method for automatic placement of thermoplastic composite materials according to claim 1, characterized in that: The thermoplastic prepreg (15) is arranged on a material roll (14).

5. The method for automatic placement and molding of thermoplastic composite materials according to claim 1, characterized in that: The thermoplastic prepreg (15) enters the laying channel through the second guide wheel (13) and the first guide wheel (12).

6. The method for automatic placement of thermoplastic composite materials according to claim 1, characterized in that: The laying channel comprises a clamping part, a re-feeding part and a shearing part which are arranged in sequence from top to bottom.

7. The method for automatic placement of thermoplastic composite materials according to claim 6, characterized in that: The clamping part comprises a clamping controller (10), a clamping cylinder (11), a clamping pressure wheel (16), and a clamping plate (17). The clamping controller (10) is connected to the clamping cylinder (11), and the clamping cylinder (11) is connected to the clamping pressure wheel (16). The clamping controller (10) controls the opening and closing of the clamping cylinder (11), and the clamping pressure wheel (16) clamps the thermoplastic prepreg (15) on the clamping plate (17) under the push of the clamping cylinder (11).

8. The method for automatic placement of thermoplastic composite materials according to claim 6, characterized in that: The re-feeding part comprises a re-feeding controller (8), a re-feeding cylinder (9), a re-feeding shaft (20), a re-feeding pressure wheel (18) and a re-feeding motor (19). The re-feeding controller (8) is connected to the re-feeding cylinder (9). The re-feeding controller (8) controls the opening and closing of the re-feeding cylinder (9). The re-feeding pressure wheel (18) is connected to the re-feeding cylinder (9). The re-feeding pressure wheel (18) presses the thermoplastic prepreg (15) onto the re-feeding shaft (20) under the push of the re-feeding cylinder (9). The re-feeding motor (19) is connected to the re-feeding shaft (20). The re-feeding shaft (20) conveys the thermoplastic prepreg (15) downward under the conveyance of the re-feeding motor (19).

9. The method for automatic placement of thermoplastic composite materials according to claim 6, characterized in that: The shearing part comprises a shearing controller (6), a shearing cylinder (7) and a shearing knife (22); the shearing controller (6) is connected to the shearing cylinder (7), and the shearing cylinder (7) is connected to the shearing knife (22); the shearing controller (6) controls the opening and closing of the shearing cylinder (7), and the shearing knife (22) cuts the thermoplastic prepreg (15) in the shearing groove under the push of the shearing cylinder (7), thereby realizing continuous laying.

10. The method for automatic placement of thermoplastic composite materials according to claim 6, characterized in that: A clamping part is arranged below the shearing part, and the clamping part comprises a clamping controller (23), a clamping cylinder (5) and a pressing roller (4); the clamping controller (23) is connected to the clamping cylinder (5), and the clamping cylinder (5) is connected to the pressing roller (4); the clamping controller (23) controls the opening and closing of the clamping cylinder (5), and the pressing roller (4) adheres the thermoplastic impregnation material (15) to the polyimide coating (2) on the surface of the self-heating and cooling mold (1) under the push of the clamping cylinder (5).

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