Production process of thermoplastic carbon plate

Abstract

The invention relates to the technical field of thermoplastic carbon plate manufacturing, and discloses a thermoplastic carbon plate production process which comprises the following steps: S1, preparing materials; s2, cutting is carried out; s3, carrying out preforming; s4, baking and putting into a mold; s5, cold pressing; s6, taking a mold; s7, polishing is conducted; s8, detecting; and S9, packaging. A thermoplastic carbon fiber prepreg sheet is locally heated and bonded through ultrasonic electric welding, and then an electric heating lamp is arranged right above a mold entering position of a hot press table, so that the thermoplastic material can be accurately softened by baking, the thermoplastic material is ensured to be fully softened and uniformly heated, and when the thermoplastic material is completely fed into a mold after being softened by baking, the thermoplastic material can be fully heated. An operator rapidly uses the straightening jig to flatly place the thermoplastic material and straighten the position, and then immediately covers the upper mold of the forming mold, so that the exposure time of the thermoplastic material in the external environment is shortened, and the risk that local resin is cured in advance due to environment temperature fluctuation and improper transfer time control is effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of thermoplastic carbon fiber plate manufacturing technology, and in particular to a production process for thermoplastic carbon fiber plates. Background Technology

[0002] Thermoplastic carbon fiber composite material, as a high-performance composite material, is widely used in aerospace, automotive manufacturing, sporting goods, medical devices, and high-end electronic equipment due to its lightweight, high strength, corrosion resistance, impact resistance, and recyclability. Its core advantage lies in achieving a balance between the material's mechanical properties and molding flexibility through the composite of thermoplastic resin matrix and carbon fiber, thus meeting the demands for lightweighting and integrated structural functionality.

[0003] Currently, the manufacturing of existing thermoplastic carbon fiber sheets typically employs a step-by-step process of "heating and softening - transfer molding - hot pressing - cooling and demolding": first, thermoplastic resin and carbon fiber prepreg are heated to a softened state, then quickly transferred to a mold for hot pressing, and finally demolded after prolonged natural or forced cooling. However, during the transfer of the softened prepreg to the mold, environmental temperature fluctuations or improper control of the transfer time can easily lead to premature curing of local resins, affecting the molding quality of the product. Furthermore, the product requires a long cooling period after hot pressing before cold pressing and reshaping, resulting in low equipment utilization, increased energy costs, and difficulty in adapting to the needs of large-scale continuous production.

[0004] Therefore, a new technical solution needs to be researched to address the above problems. Summary of the Invention

[0005] In view of this, the present invention addresses the deficiencies of the existing technology, and its main objective is to provide a production process for thermoplastic carbon sheets.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A manufacturing process for thermoplastic carbon fiber sheets, comprising:

[0008] S1. Material preparation: Select thermoplastic unidirectional carbon fiber prepreg or braided carbon fiber prepreg as raw materials according to production needs.

[0009] S2. Cutting: The prepreg is cut using cutting equipment, and the cutting process is carried out according to the actual required cutting angle, size, function, shape and other factors to obtain carbon fiber sheets;

[0010] S3. Pre-forming: The cut carbon yarn sheets are stacked and arranged according to the required mechanical properties, and then the carbon yarn sheets are bonded together by ultrasonic spot welding to obtain the pre-shaped part.

[0011] S4. Baking and Molding: Place the molding mold on the pre-molding position of the hot press, then place the thermoplastic material on the molding mold, and use an electric heating lamp to soften the thermoplastic material, so that it is fully softened and completely enters the molding mold. Then, the operator uses a leveling fixture to place the thermoplastic material flat and in the correct position, and then puts the upper mold cover on the molding mold to complete the molding process.

[0012] S5. Cold pressing: After the thermoplastic material is put into the mold, the molding die is placed in a hot press that is always kept at a low temperature, and cold pressing is performed using the temperature and pressure of the hot press.

[0013] S6. Remove the mold. After the mold cools to 40°C, push the molding mold out of the hot press and then open the mold to remove the product.

[0014] S7. Polishing: Polish the edges of the product to make them smooth.

[0015] S8. Inspection: Before the products are shipped, according to the different product numbers and product quality requirements, the products are placed one by one on the corresponding automatic weighing machine or other weighing machine for weighing and inspection to distinguish between good and defective products.

[0016] S9. Packaging: Pack the qualified products according to the product packaging requirements.

[0017] As a further explanation, in the stacking and sorting process of step S3, carbon yarn sheets at different angles are cross-stacked.

[0018] As further explained, in step S3, the ultrasonic spot welding method uses a high-frequency ultrasonic welding machine with an amplitude set to 20-35 μm and a static pressure range of 0.2-0.6 MPa. The contact surface geometry is selected according to the thickness of the preform, and its texture depth is ≤50 μm.

[0019] As further explained, in step S4, the electric baking lamp is positioned directly above the mold entry position of the hot press, and the distance between the electric baking lamp and the molding mold is 15-25cm.

[0020] To further elaborate, the baking time for thermoplastic materials by electric baking lamp is 10-60 seconds.

[0021] As further explained, in step S5, the temperature of the hot press is 9-12℃.

[0022] As a further explanation, between step S7 and step S8, a protective film is also applied, and a protective film is applied to the exposed surface of the product according to the product's external surface protection requirements.

[0023] As a further explanation, between step S7 and step S8, a sandblasting process is also included, in which diamond abrasive is sprayed onto the surface of the product to make the surface uneven, according to the appearance requirements of the product.

[0024] As a further explanation, between steps S7 and S8, there is also a spraying process. According to the appearance requirements of the product, the corresponding surface of the product is sprayed with oil, and the product after spraying is placed in an oven for drying.

[0025] As a further explanation, between step S8 and step S9, metal detection is also included, in which the weighed good products are placed into a metal detection machine for metal detection, and defective products containing metal components are selected.

[0026] Compared with the prior art, the present invention has obvious advantages and beneficial effects. Specifically, as can be seen from the above technical solution:

[0027] 1. Ultrasonic welding is used to locally heat and bond thermoplastic carbon fiber prepreg sheets, avoiding misalignment during transport and layup. An electric heating lamp is placed directly above the mold entry point on the hot press, with the distance between the lamp and the mold controlled at 20-25cm, and the preform baking time at 10-60 seconds. This allows for precise softening of the thermoplastic material, ensuring it is fully softened and evenly heated. Once the softened material is fully placed into the mold, the operator quickly uses a leveling fixture to place it flat and align it correctly. The upper mold cover is then immediately closed, reducing the material's exposure time to the external environment. This effectively lowers the risk of premature resin curing due to temperature fluctuations and improper transfer time control, thus ensuring product molding quality and resulting in more stable mechanical properties and appearance.

[0028] 2. After the thermoplastic material is fully softened by the electric heating lamp and completely enters the molding mold, the operator quickly uses the leveling fixture to place the thermoplastic material flat and in the correct position. Then, it is quickly transferred to the hot press, which is always at a low temperature, for cold pressing. There is no need for a long cooling process, which greatly shortens the product production cycle and improves production efficiency.

[0029] 3. By employing the combined effects of ultrasonic welding, electric baking lamps, and low-temperature cold pressing, efficient and stable thermoplastic carbon fiber plate production is achieved, thereby improving production efficiency. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 A schematic diagram of the production process of a thermoplastic carbon sheet provided by the present invention;

[0032] Figure 2 A flowchart illustrating step S3 provided by the present invention;

[0033] Figure 3 This is a flowchart illustrating step S4 of the present invention. Detailed Implementation

[0034] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0035] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0036] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0039] In one embodiment of the present invention, such as Figure 1-3 As shown, a manufacturing process for a thermoplastic carbon fiber sheet is provided, including:

[0040] S1. Material preparation: Select thermoplastic unidirectional carbon fiber prepreg or woven carbon fiber prepreg as raw materials according to production needs.

[0041] In this embodiment, the thermoplastic carbon fiber prepreg is any type of thermoplastic prepreg, such as PA, PC, PA6, PA66, etc., or thermoplastic glass fiber prepreg can be used instead. The reinforcing material of the thermoplastic carbon fiber prepreg is any type of reinforcing material, such as carbon fiber, glass fiber, etc.

[0042] S2. Cutting: The prepreg is cut using cutting equipment, and the cutting process is carried out according to the actual required cutting angle, size, function, shape and other factors to obtain carbon fiber sheets.

[0043] In this embodiment, the carbon yarn sheet needs to be cut according to the actual production situation. The cut carbon yarn sheet includes the main yarn that plays a major supporting and mechanical role, the half yarn that plays a partial supporting role, and the reinforcing yarn that plays a local reinforcing role. The size of the main yarn is usually the size of the corresponding full-length carbon plate, the size of the half yarn is usually half the size of the corresponding full-length carbon plate, and the size of the reinforcing yarn is usually the size of the corresponding functional area. The reinforcing yarn can correspond to the arch part, the arch sidewall part, etc.

[0044] S3. Pre-forming: The cut carbon yarn sheets are stacked and arranged according to the required mechanical properties, and then the carbon yarn sheets are bonded together by ultrasonic spot welding to obtain the pre-shaped part.

[0045] In the process of layering, carbon fiber sheets at different angles are cross-stacked according to the required mechanical properties to improve the structural stability and mechanical effect of the carbon fiber plate. For example, two layers at -19° and +19° are connected, or two layers at 0° and 90° are connected, etc. This symmetrical layup method of cross-stacking carbon fiber sheets enables the product to have high bending strength and high torsional strength.

[0046] In the ultrasonic spot welding process, a high-frequency ultrasonic welding machine with a frequency of 30–40 kHz is used, with an amplitude set to 20–35 μm and a static pressure range of 0.2–0.6 MPa. The contact surface geometry is selected according to the thickness of the pre-formed part, and the texture depth is ≤50 μm to enhance vibration transmission efficiency. During the ultrasonic spot welding process, the pre-pressure stage has a pressure of 0.2 MPa, maintained for 0.1–0.3 s, to eliminate interlayer gaps in the pre-formed sheet. The vibration stage has an amplitude of 25 μm, maintained for 0.5–1.5 s, allowing the mechanical energy of the ultrasonic spot welder to be converted into the heat energy of the welding head. The holding pressure stage has a pressure of 0.4 MPa, maintained for 0.5–1.0 s, which effectively inhibits molecular chain retraction and promotes diffusion entanglement.

[0047] By using an ultrasonic spot welding machine to locally heat and bond the preformed sheets, misalignment during transportation and layup is avoided, thus improving the production quality of subsequent products.

[0048] In other embodiments, ultrasonic spot welding can also be replaced by welding methods such as laser local heating bonding, hot air local welding with a micro hot air gun, and electrostatic adsorption technology to achieve the layer bonding of preforms.

[0049] S4. Baking and Molding: Place the molding mold on the pre-molding position of the hot press, then place the thermoplastic material on the molding mold, and use an electric heating lamp to soften the thermoplastic material until it is fully softened and completely enters the molding mold. Then, the operator uses a leveling fixture to place the thermoplastic material flat and in the correct position, and then closes the upper mold cover of the molding mold to complete the molding process.

[0050] The electric heating lamp is positioned directly above the mold entry point on the hot press, with a distance of 15-25cm, preferably 20cm, between the lamp and the mold. The electric heating lamp bakes the thermoplastic material for 10-60 seconds, and by controlling the temperature rise within this range, it can process most thermoplastic materials.

[0051] In this embodiment, an electric heating lamp with a temperature adjustable between 80°C and 350°C is selected. The operator adjusts the heating time according to the different thicknesses and sizes of the thermoplastic materials. This type of electric heating lamp can handle most thermoplastic materials. After the thermoplastic material is heated to a molten state by the electric heating lamp, the heating is complete. The lamp is then turned off, and the softened material gradually slides into the mold cavity. If the molten material becomes skewed, the operator can use a straightening fixture to straighten it, ensuring that the material is fully adhered to the molding die.

[0052] By using an electric heating lamp to precisely heat the thermoplastic material locally, temperature loss during the transfer process is avoided, creating stable operating conditions for subsequent molding processes.

[0053] In other embodiments, the electric baking lamp can be replaced by infrared radiation heating, induction heating, microwave heating, etc., to achieve the melting of thermoplastic materials.

[0054] S5. Cold pressing: After the thermoplastic material is placed into the mold, it is placed in a hot press that is always kept at a low temperature, and cold pressing is performed using the temperature and pressure of the hot press. The temperature of the hot press is always maintained in the range of 9-12℃, preferably 10℃. By keeping the hot press at a low temperature, the mold can be cooled quickly after entering, which greatly shortens its cooling time and thus shortens its molding cycle.

[0055] In other embodiments, cryogenic cold pressing can be achieved by filling the mold sandwich with a phase change material or liquid CO2. W Replace the mold with methods such as jet cooling and thermoelectric cooling to achieve rapid cooling of the molding die.

[0056] S6. Remove the mold. After the mold cools to 40°C, push the molding mold out of the hot press and then open the mold to remove the product.

[0057] S7. Polishing: Polish the edges of the product to make them smooth.

[0058] S8. Inspection: Before the products are shipped, according to the different product numbers and product quality requirements, the products are placed one by one on the corresponding automatic weighing machine or other weighing machine for weighing and inspection to distinguish between good and defective products.

[0059] S9. Packaging: Based on the product packaging requirements, the qualified products are packaged. The products are classified and packaged according to the corresponding code segment. If the product surface has a glossy surface that needs protection, a plastic film or soft paper is added between the glossy surfaces for protection. At the same time, the packaged products are vacuum-sealed according to their numbers and quantities before being shipped. This operation method can effectively protect the product surface from scratches and can also effectively control the quantity of products.

[0060] Ultrasonic welding is used to locally heat and bond thermoplastic carbon fiber prepreg sheets, avoiding misalignment during transport and layup. An electric heating lamp is placed directly above the mold entry point on the hot press, with the distance between the lamp and the mold controlled at 20-25cm, and the preform baking time at 10-60 seconds. This allows for precise softening of the thermoplastic material, ensuring it is fully softened and evenly heated. Once the softened material is fully placed into the mold, the operator quickly uses a leveling fixture to place it flat and align it correctly. The upper mold cover is then immediately closed, reducing the material's exposure time to the external environment. This effectively lowers the risk of premature resin curing due to temperature fluctuations and improper transfer time control, thus ensuring product molding quality and resulting in more stable mechanical properties and appearance.

[0061] After the thermoplastic material is fully softened by an electric heating lamp and completely inserted into the molding die, the operator quickly uses a leveling fixture to place the thermoplastic material flat and in the correct position. Then, it is quickly transferred to a hot press machine that is always at a low temperature for cold pressing. This eliminates the need for a long cooling process, greatly shortening the product production cycle and improving production efficiency.

[0062] By employing the combined effects of ultrasonic welding, electric baking lamps, and low-temperature cold pressing, efficient and stable thermoplastic carbon fiber plate production has been achieved, thereby improving production efficiency.

[0063] After being placed into the mold, the molding die is placed in a hot press that is always kept at a low temperature for cold pressing. The low temperature environment can effectively inhibit the further curing reaction of the resin, maintain the fluidity of the resin during the cold pressing process, and allow the resin to better fill the mold cavity and be evenly distributed between the carbon fiber sheets. This avoids molding defects caused by premature local resin curing, such as voids and delamination, and improves the density and overall quality of the product.

[0064] Preferably, between step S7 and step S8, a protective film is applied. According to the product's external surface protection requirements, a protective film is applied to the exposed surface of the product. The protective film can be made of R-adhesive, masking tape, adhesive tape, pearlescent paper, etc., to prevent subsequent operations from cutting the product's surface and causing scratches.

[0065] Preferably, between steps S7 and S8, a sandblasting process is further included. Depending on the product's appearance requirements, corundum is sprayed onto the product's surface, creating an uneven surface that appears uniformly rough from a distance. This increases the surface roughness, significantly improving the fit between the product and the midsole. In this embodiment, watermarks are affixed to the corresponding areas of the sandblasted product to provide identification, and the product is then baked in an oven to dry.

[0066] Preferably, between step S7 and step S8, an oil spraying process is also included. According to the appearance requirements of the product, the corresponding surface of the product is sprayed with oil, and the product after spraying is placed in an oven for drying, so that the product surface has a smooth exposed effect. At the same time, the protective film on its surface is removed after drying.

[0067] Preferably, between step S8 and step S9, metal detection is also included, in which the weighed good products are placed in a metal detector for metal detection, and defective products containing metal components are selected. Through metal detection, defective products containing metal components are screened out, thereby improving product safety.

[0068] The above are merely preferred embodiments of the present invention, and only specifically describe the technical principles of the present invention. These descriptions are only for explaining the principles of the present invention and should not be construed as limiting the scope of protection of the present invention in any way. Based on this explanation, any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention, as well as other specific embodiments of the present invention that can be conceived by those skilled in the art without creative effort, should be included within the scope of protection of the present invention.

Claims

1. A manufacturing process for thermoplastic carbon fiber sheets, characterized in that, include: S1. Material preparation: Select thermoplastic unidirectional carbon fiber prepreg or braided carbon fiber prepreg as raw materials according to production needs. S2. Cutting: The prepreg is cut using cutting equipment, and the cutting process is carried out according to the actual required cutting angle, size, function, shape and other factors to obtain carbon fiber sheets; S3. Pre-forming: The cut carbon yarn sheets are stacked and arranged according to the required mechanical properties, and then the carbon yarn sheets are bonded together by ultrasonic spot welding to obtain the pre-shaped part. S4. Baking and Molding: Place the molding mold on the pre-molding position of the hot press, then place the thermoplastic material on the molding mold, and use an electric heating lamp to soften the thermoplastic material, so that it is fully softened and completely enters the molding mold. Then, the operator uses a leveling fixture to place the thermoplastic material flat and in the correct position, and then puts the upper mold cover on the molding mold to complete the molding process. S5. Cold pressing: After the thermoplastic material is put into the mold, the molding die is placed in a hot press that is always kept at a low temperature, and cold pressing is performed using the temperature and pressure of the hot press. S6. Remove the mold. After the mold cools to 40°C, push the molding mold out of the hot press and then open the mold to remove the product. S7. Polishing: Polish the edges of the product to make them smooth. S8. Inspection: Before the products are shipped, according to the different product numbers and product quality requirements, the products are placed one by one on the corresponding automatic weighing machine or other weighing machine for weighing and inspection to distinguish between good and defective products. S9. Packaging: Pack the qualified products according to the product packaging requirements.

2. The production process of the thermoplastic carbon board according to claim 1, characterized in that, In the stacking and sorting process of step S3, carbon yarn sheets at different angles are cross-stacked.

3. The production process of the thermoplastic carbon board according to claim 1 or 2, characterized in that, In step S3, the ultrasonic spot welding method uses a high-frequency ultrasonic welding machine with an amplitude set to 20-35 μm and a static pressure range of 0.2-0.6 MPa. The contact surface geometry is selected according to the thickness of the preform, and its texture depth is ≤50 μm.

4. The production process of the thermoplastic carbon board according to claim 1, characterized in that, In step S4, the electric heating lamp is positioned directly above the mold entry point of the hot press, and the distance between the electric heating lamp and the molding mold is 15-25cm.

5. The production process of the thermoplastic carbon board according to claim 1 or 4, characterized in that, The baking time for thermoplastic materials by electric baking lamp is 10-60 seconds.

6. The production process of the thermoplastic carbon board according to claim 1, characterized in that, In step S5, the temperature of the hot press is 9-12℃.

7. The production process of the thermoplastic carbon board according to claim 1, characterized in that, Between steps S7 and S8, a protective film is applied, and a protective film is applied to the exposed surface of the product according to the product's external surface protection requirements.

8. The production process of the thermoplastic carbon board according to claim 1, characterized in that, Between steps S7 and S8, a sandblasting process is also included, in which diamond abrasive is sprayed onto the surface of the product to make the surface uneven, according to the appearance requirements of the product.

9. The production process of the thermoplastic carbon board according to claim 1, characterized in that, Between steps S7 and S8, a spraying process is also included. According to the appearance requirements of the product, the corresponding surface of the product is sprayed with oil, and the product after spraying is placed in an oven for drying.

10. The production process of the thermoplastic carbon sheet according to claim 1, characterized in that, Between steps S8 and S9, metal detection is also included, in which the weighed good products are placed into a metal detector for metal detection, and defective products containing metal components are selected.

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