Carbon fiber hub high-pressure RTM mold machining method and device

Abstract

The invention relates to the field of hubs, in particular to a high-pressure RTM mold machining device for a carbon fiber hub. The invention discloses a carbon fiber hub high-pressure RTM mold machining method. The method comprises the following steps that early-stage preparation is conducted, specifically, a prefabricated wheel net is woven through an automatic three-dimensional weaving machine according to a program; mold closing and sealing: putting the prefabricated body wheel net into an HP-RTM mold by a mechanical arm, positioning in the mold, closing the mold, locking through a sealing structure, starting a vacuum system to pump and discharge air in a mold cavity, vacuumizing for 60 seconds, vacuumizing to 5mbr, and discharging air in the mold cavity, wherein the temperature of the HP-RTM mold is 105-110 DEG C; and high-pressure glue injection: heating the HP-RTM mold to 115-125 DEG C, injecting the premixed resin and the curing agent from the center of the bottom of the mold by a high-pressure injection machine, and quickly prefabricating the wheel net by using the resin under high pressure. The injection mold has the beneficial effects that an in-mold sealing function, a vacuumizing device and a glue (resin) injection structure after mold closing are added, the processing period is short, and the size consistency is good.

Description

Technical Field

[0001] This invention relates to the field of wheel hubs, and in particular to a method and apparatus for processing high-pressure RTM molds for carbon fiber wheel hubs. Background Technology

[0002] Currently, the manufacturing process for carbon fiber wheels is slow, which increases cooling time, affects the production cycle, and results in poor dimensional consistency. Summary of the Invention

[0003] To address the aforementioned technical problems of poor dimensional consistency and long cooling time, this invention provides a method and apparatus for processing high-pressure RTM molds for carbon fiber wheel hubs.

[0004] The technical solution of the present invention is as follows: The processing method for high-pressure RTM molds for carbon fiber wheel hubs is as follows: Preliminary preparation: Use an automatic 3D weaving machine to weave the prefabricated mesh according to the program; Mold closing and sealing: The robotic arm places the preformed wheel mesh into the HP-RTM mold, positions it in the mold, the HP-RTM mold temperature is 105-110℃, closes the mold and locks it through the sealing structure, starts the vacuum system to pump out the air in the mold cavity, pumps the vacuum for 60 seconds, pumps the vacuum to 5mbr, and then removes the air from the mold cavity. High-pressure injection: The HP-RTM mold is heated to 115-125℃. The high-pressure injection machine injects the premixed resin and curing agent from the center of the bottom of the mold. High pressure is used to quickly preform the resin into a ring. The injection pressure is 10-15 MPa, 1.0-6.0 MPa. High-pressure injection only takes 30 seconds to 2 minutes, and the temperature is kept constant for 8-15 minutes. In-mold curing: Maintain high temperature and pressure in the mold. After the resin is completely cured, inject resin into the side holes to form a surface resin film and perform secondary curing. Maintain the mold temperature at 120-130℃ and the mold cavity pressure at 5-12MPa for the main curing time of 120 seconds. With the addition of an accelerator, this time can be shortened to 90 seconds. The surface resin film cures in about 30-60 seconds. Cooling and demolding: Active cooling, cooling rate 2-4℃ / min, until 60-70℃, open the mold, open the ejection mechanism to remove the hub, and transfer it to the cooling fixture to cool to room temperature; Post-processing: After trimming, machining positioning holes, and dimensional inspection, the finished product is obtained.

[0005] The cutting process takes 30-60 seconds, and the trimming inspection takes about 2-3 minutes.

[0006] The main resin commonly used is DER332 epoxy resin, which has a viscosity of 45 mPa•s at 80°C. The curing agent is often 1,3-BAC (1,3-bis(aminomethyl)cyclohexane), which has a viscosity of only 9.1 mPa•s (25°C).

[0007] The accelerator is bisphenol A.

[0008] The standard ratio is 100g of DER332 epoxy resin mixed with 20.6g of 1,3-BAC (1,3-bis(aminomethyl)cyclohexane) (weight ratio approximately 4.85:1).

[0009] Bisphenol A is added at 4% of the weight of the epoxy resin, that is, 100g of epoxy resin is mixed with 20.6g of curing agent and 4.1g of accelerator.

[0010] A carbon fiber wheel hub high-pressure RTM mold processing device and a carbon fiber wheel hub high-pressure RTM mold processing method are provided. The device includes an upper mold and a lower mold. The upper mold includes a cover plate and a cavity body. A cavity is provided at the bottom of the cavity body. A vacuum device is provided on the cavity body and is connected to the cavity. The cavity body is connected to the cover plate. The lower mold includes a mounting base and a core. The core is provided in the middle of the mounting base. A core slider body is arranged around the outside of the core. The core slider body forms a complete circle after being closed. The inner wall of the mold cavity is in close contact with the outer wall of the core slider body to form a sealing structure. A heating and cooling system is provided for the cavity body, the core, and the core slider body. The cavity is provided with a glue injection port.

[0011] The cavity body has a sealing strip a at the top of the cavity, a sealing strip b on the core surface, a sealing strip c on the outer wall of the lower end of the core, and a sealing strip d on the inner wall of the core slider body. The sealing structure includes a double rubber sealing ring structure at the edge of the mold cavity, with the first sealing ring responsible for sealing the glue and the second sealing the air, and the two grooves being 10mm apart; secondly, a straight sealing structure is adopted at the ejector pin hole, with two annular sealing grooves on the inner wall of the ejector pin hole, and an O-ring seal inside, with the uppermost sealing groove 10-15mm from the mold surface.

[0012] The rear of the core slider body is provided with a socket, into which the movable rod of the hydraulic cylinder is inserted. The hydraulic cylinder is fixed on the mounting base by a hydraulic cylinder mounting seat. The mounting base is provided with a guide block mounting groove, and a guide block is provided on the mounting groove. The bottom end of the core slider body is provided with a sliding groove, which is engaged with the guide block. Both ends of the core slider body are in contact with wear-resistant blocks, and slider pressure strips are provided on the wear-resistant blocks.

[0013] The surface of the cavity body is provided with a mounting block, and the mounting block is provided with a cover plate.

[0014] Using the technical solution of this invention, the structure is novel, the design is ingenious and simple, and it adds an in-mold sealing function, a vacuum device, and a resin injection structure after mold closing. The processing cycle is short, and the dimensional consistency is good. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the structure of the cavity body of the present invention; Figure 3 This is a schematic diagram of the structure of the molded product of this invention; Figure 4 This is a schematic diagram of the core structure of the present invention; Figure 5 This is a schematic diagram of the structure of part of the present invention; Figure 6 This is a schematic diagram of the mounting base of the present invention; Figure 7 , 8 This is a schematic diagram of the structure of the core slider body of the present invention; Figure 9 This is a schematic diagram of the core guide block of the present invention; Figure 10 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments. Example

[0017] like Figure 1 , 2 The carbon fiber wheel hub high-pressure RTM mold processing method shown in 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 is characterized by the following steps: Preliminary preparation: Use an automatic 3D weaving machine to weave the prefabricated mesh according to the program; Mold closing and sealing: The robotic arm places the preformed wheel mesh into the HP-RTM mold, positions it in the mold, the HP-RTM mold temperature is 105-110℃, closes the mold and locks it through the sealing structure, starts the vacuum system to pump out the air in the mold cavity, pumps the vacuum for 60 seconds, pumps the vacuum to 5mbr, and then removes the air from the mold cavity. High-pressure injection: The HP-RTM mold is heated to 115-125℃. The high-pressure injection machine injects the premixed resin and curing agent from the center of the bottom of the mold. High pressure is used to quickly preform the resin into a ring. The injection pressure is 10-15 MPa, 1.0-6.0 MPa. High-pressure injection only takes 30 seconds to 2 minutes, and the temperature is kept constant for 8-15 minutes. In-mold curing: Maintain high temperature and pressure in the mold. After the resin is completely cured, inject resin into the side holes to form a surface resin film and perform secondary curing. Maintain the mold temperature at 120-130℃ and the mold cavity pressure at 5-12MPa for the main curing time of 120 seconds. With the addition of an accelerator, this time can be shortened to 90 seconds. The surface resin film cures in about 30-60 seconds. Cooling and demolding: Active cooling, cooling rate 2-4℃ / min, until 60-70℃, open the mold, open the ejection mechanism to remove the hub, and transfer it to the cooling fixture to cool to room temperature; Post-processing: After trimming, machining positioning holes, and dimensional inspection, the finished product is obtained.

[0018] The cutting process takes 30-60 seconds, and the trimming inspection takes about 2-3 minutes.

[0019] The main resin commonly used is DER332 epoxy resin, which has a viscosity of 45 mPa•s at 80°C. The curing agent is often 1,3-BAC (1,3-bis(aminomethyl)cyclohexane), which has a viscosity of only 9.1 mPa•s (25°C).

[0020] The accelerator is bisphenol A.

[0021] The standard ratio is 100g of DER332 epoxy resin mixed with 20.6g of 1,3-BAC (1,3-bis(aminomethyl)cyclohexane) (weight ratio approximately 4.85:1).

[0022] Bisphenol A is added at 4% of the weight of the epoxy resin, that is, 100g of epoxy resin is mixed with 20.6g of curing agent and 4.1g of accelerator.

[0023] A carbon fiber wheel hub high-pressure RTM mold processing device and a carbon fiber wheel hub high-pressure RTM mold processing method are provided. The device includes an upper mold and a lower mold. The upper mold includes a cover plate 1 and a cavity body 2. The cavity body 2 has a cavity at its bottom and a vacuum device 3 on it. The vacuum device 3 is connected to the cavity. The cavity body 2 is connected to the cover plate 1. The lower mold includes a mounting base and a core 4. The core 4 is set in the middle of the mounting base. A core slider body 5 is arranged around the outside of the core 4. The core slider body 5 forms a complete circle when closed. The inner wall of the mold cavity is in close contact with the outer wall of the core slider body 5 to form a sealing structure. The cavity body 2, the core 4 and the core slider body 5 are heated and cooled. The cavity is provided with a glue injection port.

[0024] The top of the cavity body 2 is provided with a sealing strip a6, the surface of the core 4 is provided with a sealing strip b7, the lower outer wall of the core 4 is provided with a sealing strip c, and the inner wall of the core slider body 5 is provided with a sealing strip d. The sealing structure includes a double rubber sealing ring structure at the edge of the mold cavity. The first sealing ring is responsible for sealing the glue, and the second sealing the air. The distance between the two grooves is 10mm. Secondly, a straight sealing structure is adopted at the ejector pin hole. Two annular sealing grooves are opened on the inner wall of the ejector pin hole, and O-rings are built in it. The uppermost sealing groove is 10-15mm away from the mold surface.

[0025] The rear of the core slider body 5 is provided with a socket 8, into which the movable rod of the hydraulic cylinder is inserted. The hydraulic cylinder is fixed on the mounting base by a hydraulic cylinder mounting seat. The mounting base is provided with a guide block mounting groove 9, and a guide block 10 is provided on the mounting groove 9. The bottom end of the core slider body 5 is provided with a sliding groove 11, which is engaged with the guide block 10. Both ends of the core slider body 5 are in contact with wear-resistant blocks 12, and a slider pressure strip 13 is provided on the wear-resistant blocks 12.

[0026] The surface of the cavity body 2 is provided with a mounting block, and a cover plate 1 is provided on the mounting block.

[0027] Unlike the traditional method of using a vacuum autoclave where carbon fiber is laid out, resin is applied, and the mold is closed before being placed in the autoclave for molding, our method uses a high-pressure press. The pre-woven carbon fiber mesh is made using an automatic three-dimensional weaving machine, which greatly improves automation and precision while significantly reducing workload. The high-pressure press is used to close the mold, create a vacuum, and inject resin for molding. The purpose of vacuuming is to eliminate air inside the product. Injecting resin after mold closing effectively ensures dimensional consistency.

[0028] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method of machining a carbon fiber wheel hub high pressure RTM mold characterized by: The steps are as follows: Preparation: use an automatic three-dimensional weaving machine to weave a preform wheel net according to the program; Sealing: the mechanical arm puts the preform wheel net into the HP-RTM mold, positions it, the HP-RTM mold temperature is 105-110℃, the mold is closed and locked through the sealing structure, the vacuum system is started to exhaust the air in the mold cavity, and the vacuum is extracted for 60 seconds to 5mbr; High-pressure injection: the HP-RTM mold is heated to 115-125℃, the premixed resin and curing agent are injected from the bottom center of the mold by a high-pressure injection machine, and the resin is quickly preformed in the preform wheel net by high pressure, 10-15Mpa, injection pressure 1.0-6.0MPa, high-pressure injection only needs 30 seconds-2 minutes, constant temperature 8-15 minutes; In-mold curing: keep the mold at high temperature and high pressure, inject resin into the side hole to form a surface resin film and secondary curing after the resin is completely cured, the mold temperature is kept at 120-130℃, the mold cavity pressure is 5-12MPa, the main curing is kept for 120 seconds; after adding the accelerator, it can be shortened to 90 seconds, and the surface resin film is cured for about 30-60 seconds; Cooling and demolding: active cooling, cooling speed 2-4℃ / min, temperature drops to 60-70℃, mold opening, ejection mechanism is opened to take out the hub, and it is transferred to a cooling tool to cool to room temperature; Post-processing: after trimming, processing positioning holes and size detection, the finished product is obtained.

2. The carbon fiber wheel hub high pressure RTM mold processing method according to claim 1, characterized in that: The cutting time is 30-60 seconds, and the trimming and detection time is about 2-3 minutes.

3. The carbon fiber wheel hub high pressure RTM mold processing method according to claim 1, characterized in that: The main resin commonly used is D.E.R.332 epoxy resin, which has a viscosity of 45mPa·s at 80℃, and the curing agent is usually 1,3-BAC (1,3-bis(aminomethyl)cyclohexane), which has a viscosity of only 9.1mPa·s (25℃).

4. The carbon fiber wheel hub high pressure RTM mold processing method of claim 1, wherein: The accelerator is bisphenol A.

5. The carbon fiber wheel hub high pressure RTM mold processing method of claim 3, wherein: The standard ratio is D.E.R.332 epoxy resin 100g and 1,3-BAC (1,3-bis(aminomethyl)cyclohexane) 20.6g (weight ratio about 4.85:1).

6. The carbon fiber wheel hub high pressure RTM mold processing method according to claim 5, characterized in that: 4% of bisphenol A is added by weight of epoxy resin, that is, 100g of epoxy resin is matched with 20.6g of curing agent and 4.1g of accelerator.

7. A carbon fiber wheel hub high pressure RTM mold processing device using the carbon fiber wheel hub high pressure RTM mold processing method of claim 1, comprising an upper mold and a lower mold, characterized in that: The upper mold includes a cover plate (1) and a mold cavity body (2), the bottom of the mold cavity body (2) is provided with a mold cavity, the mold cavity body (2) is provided with a vacuum device (3), the vacuum device (3) is communicated with the mold cavity, the mold cavity body (2) is connected with the cover plate (1), the lower mold includes a mounting seat and a core (4), the core (4) is arranged in the middle of the mounting seat, the core (4) is annularly arranged outside the core slider body (5), the core slider body (5) forms a whole circle after being closed, the inner wall of the mold cavity and the outer wall of the core slider body (5) are in close contact to form a sealing structure, the mold cavity body (2), the core (4) and the core slider body (5) are provided with a heating and cooling system, and the mold cavity is provided with a glue injection port.

8. The carbon fiber wheel hub high pressure RTM mold machining apparatus of claim 7, wherein: The cavity body (2) is provided with a sealing strip a (6) at the top end, the core (4) is provided with a sealing strip b (7) on the surface, the outer wall of the lower end of the core (4) is provided with a sealing strip c, and the inner wall of the core slider body (5) is provided with a sealing strip d.

9. The carbon fiber wheel hub high pressure RTM mold machining apparatus of claim 7, wherein: The rear part of the core slider body (5) is provided with a socket (8), the socket (8) is inserted into the movable rod of the oil cylinder, the oil cylinder is fixed on the mounting seat through the oil cylinder mounting seat, the mounting seat is provided with a guide block mounting groove (9), the guide block mounting groove (9) is provided with a guide block (10), the bottom end of the core slider body (5) is provided with a sliding groove (11), the sliding groove (11) is clamped on the guide block (10), the two ends of the core slider body (5) are in contact with wear-resistant blocks (12), and the wear-resistant blocks (12) are provided with sliding block pressing strips (13).

10. The carbon fiber wheel hub high pressure RTM mold machining apparatus of claim 7, wherein: The surface of the cavity body (2) is provided with a mounting block, and the mounting block is provided with a cover plate (1).

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