CN117962164A

CN117962164A - Preformed blank for HP-RTM and preparation method thereof

Info

Publication number: CN117962164A
Application number: CN202211303309.9A
Authority: CN
Inventors: 任张毓; 任明伟; 范广宏; 赵虎虎; 周玉敬; 朱祥东; 王勇
Original assignee: Dezhou Branch Of Beijing Machinery Science And Technology Guochuang Lightweight Science Research Institute Co ltd; Beijing National Innovation Institute of Lightweight Ltd
Current assignee: Dezhou Branch Of Beijing Machinery Science And Technology Guochuang Lightweight Science Research Institute Co ltd; Beijing National Innovation Institute of Lightweight Ltd
Priority date: 2022-10-24
Filing date: 2022-10-24
Publication date: 2024-05-03

Abstract

The invention relates to a preformed blank for HP-RTM and a preparation method thereof, belongs to the technical field of preformed processing, and solves the problems that the preformed method in the prior art is low in efficiency and the preformed blank is easy to deform under high pressure. The method comprises the following steps: spraying shaping powder on the surface of the fiber cloth, wherein the shaping powder is thermoplastic resin; stacking a plurality of fiber cloths, placing the fiber cloths in a pre-forming die, and heating the fiber cloths to enable the shaping powder on the surfaces of the fiber cloths to be melted; pressurizing the piled fiber cloth, thinning and preforming the fiber cloth, and simultaneously enabling the shaping powder in a molten state to permeate into fiber gaps; and cooling the pressed product to change the molten shaping powder from a liquid state to a solid state, and combining the dispersed fiber cloth into a whole to obtain a preformed blank. The method has high efficiency, and the preformed blank is not easy to deform under high pressure.

Description

Preformed blank for HP-RTM and preparation method thereof

Technical Field

The invention relates to the technical field of preforming processing, in particular to a preformed blank for HP-RTM and a preparation method thereof.

Background

The HP-RTM (High Pressure RESIN TRANSFER Molding) Molding method is to mix resin by opposite impact with High Pressure and inject the mixture into a vacuum-tight mold which is pre-laid with fiber reinforced materials and preset inserts, and then to obtain a composite material product through resin flowing filling, dipping, curing and demolding. The HP-RTM process not only shortens the filling time, but also can maintain the appearance and the surface quality of the workpiece, and has unique advantages. Because the current HP-RTM molding method is fast, the resin is punched into the mold with high pressure, and the fiber cloth which is put into the mold in advance needs to be preformed, so that the appearance of the product is preformed.

The existing preforming method is to stack each fiber cloth in a preforming mould for compression preforming, and then stack a plurality of preformed fiber cloths in an HP-RTM device for high-pressure resin injection. The fiber cloth is directly stacked in the HP-RTM device, and because the resin is injected under high pressure, the fiber cloth is easily scattered or deformed, and the effect of the HP-RTM product is affected.

Disclosure of Invention

In view of the above analysis, the present invention aims to provide a preform for HP-RTM and a method for preparing the same, which are used for solving the problem that the preform prepared by the existing preform method is easily deformed under high pressure.

In one aspect, an embodiment of the present invention provides a method for preparing a preform for HP-RTM, as shown in fig. 1, the method comprising:

(1) Spraying shaping powder on the surface of the fiber cloth, wherein the shaping powder is thermoplastic resin;

(2) Stacking a plurality of fiber cloths, placing the fiber cloths in a pre-forming die, and heating the fiber cloths to enable the shaping powder on the surfaces of the fiber cloths to be melted; pressurizing the piled fiber cloth, thinning and preforming the fiber cloth, and simultaneously enabling the shaping powder in a molten state to permeate into fiber gaps;

(3) And (3) cooling the pressed product in the step (2) to change the molten shaping powder from a liquid state to a solid state, and combining the dispersed fiber cloth into a whole to obtain a preformed blank.

Preferably, the shaping powder is at least one of polypropylene resin, polyamide resin, polyester resin, polyphenylene oxide resin and polystyrene.

Preferably, the dosage of the shaping powder is 8-12g/m ².

Preferably, in step (2), the stacking the plurality of fiber cloths includes: marking is made at the center point of each layer of fiber cloth, marking is also made at the middle part of the stacking tool, the marking points of the fiber cloth and the marking points of the tool are overlapped, and each layer of fiber cloth is stacked and placed.

Preferably, in step (2), the heating temperature is 120-180 ℃.

Preferably, in step (2), the pressure of the pressurization is 1000KN-5000KN.

Preferably, in the step (2), the heating mode is at least one of infrared heating, contact heating and microwave resonance heating.

Preferably, the method further comprises: cutting, trimming and punching the preformed blank body obtained in the step (3).

In another aspect, the invention also provides a preform obtained according to the above method.

In a third aspect, the invention also provides the use of the preform blank described above in HP-RTM.

Compared with the prior art, the invention has at least one of the following beneficial effects:

1. According to the invention, the shaping powder is sprayed on the fiber cloth, a plurality of fiber cloths are piled up, then the shaping powder is melted by heating, the melted shaping powder is permeated into fiber gaps while being preformed under pressure, so that all layers of fiber cloths in the whole preformed blank formed after cooling are tightly and uniformly bonded.

2. The shaping powder adopted by the invention is thermoplastic resin, the molecules of the thermoplastic resin are chain-shaped and crosslinked, and after cooling shaping, the thermoplastic resin can be softened again by heating and shaped again. Therefore, after the thermoplastic resin is adopted to shape the multi-layer fiber cloth, the whole preformed blank has good toughness and better rebound resilience. The HP-RTM is heated in the process of injecting the fluid at high pressure, and the thermoplastic resin is melted again due to heating, so that the preformed blank body can be prevented from being deformed, broken and damaged under the impact of the high-pressure fluid of the HP-RTM. The invention does not use thermosetting resin as a sizing agent, and the thermosetting resin is not remelted when being heated again after being heated and cooled again, has higher brittleness and is easy to be broken and damaged under the impact of high-pressure fluid of HP-RTM, thereby leading to the deformation of the preformed blank.

3. Thermoplastic resin belongs to petroleum derivatives, belongs to environment protection, and has little pollution to the environment.

4. Existing preform blanks cannot be used to make articles having a thickness in excess of 20mm because the thickness is too thick to be readily broken up by high pressure. The preformed blank has strong high-pressure impact resistance, and can be thicker, so that the product with the thickness of more than or equal to 40mm can be prepared.

5. The method cuts the prepared integral preformed blank into a plurality of blanks, and improves the blank manufacturing efficiency;

6. the preformed blank prepared by the preparation method can be used for preparing the plate spring by the HP-RTM method, can be used for preparing the battery shell, the front cover and the like by the HP-RTM method, and has a wide application range.

In the invention, the technical schemes can be mutually combined to realize more preferable combination schemes. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and drawings.

Drawings

The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, like reference numerals being used to refer to like parts throughout the several views.

FIG. 1 is a flow chart of a method of preparing a preform for HP-RTM according to the present invention.

FIG. 2 is a schematic longitudinal cross-sectional view of an HP-RTM rapid prototyping die of the present invention;

FIG. 3 is a schematic cross-sectional view of an HP-RTM rapid prototyping die of the present invention;

FIG. 4 is another schematic longitudinal cross-sectional view of the HP-RTM rapid prototyping die of the present invention;

FIG. 5 is an enlarged schematic view of the vacuum control valve seal structure and the sealant seal and air seal of the HP-RTM rapid prototyping die of the present invention;

fig. 6 is a physical diagram of the finished product of the embodiment 6.

The reference numerals are explained as follows:

100-upper die, 101-upper die fixing plate, 102-upper die cushion block, 103-upper die heat insulation plate, 104-upper die core, 105-upper die heat insulation plate, 106-pressure sensor, 107-injection port, 108-upper die temperature sensor, 109-guide sleeve, 110-vacuum system, 111-air tap, 112-vacuum pipeline, 113-vacuum cylinder, 114-vacuum control valve, 1141-O-shaped sealing ring, 1142-valve sleeve, 1143-valve rod, 115-vacuum oil circuit, 116-vacuum gauge, 120-upper die temperature controller, 200-lower die, 201-lower die fixing plate, 202-lower die cushion block, 203-lower die heat insulation plate, 204-lower die core, 205-lower die heat insulation plate, 206-sealing glue seal, 207-air seal, 208-supporting block, 209-guide pillar, 210-ejection mechanism, 211-push plate, 212-push rod, 213-ejection cylinder, 214-lower die temperature sensor, 220-lower die temperature controller and 300-cavity.

Detailed Description

The following detailed description of preferred embodiments of the application is made in connection with the accompanying drawings, which form a part hereof, and together with the description of the embodiments of the application, are used to explain the principles of the application and are not intended to limit the scope of the application.

In one aspect, the present invention provides a method of preparing a preform for HP-RTM, as shown in FIG. 1, comprising:

Compared with the prior art, the method provided by the embodiment has the advantages that the shaping powder is sprayed on the fiber cloth, a plurality of fiber cloths are piled up, then the shaping powder is melted by heating, the melted shaping powder is permeated into fiber gaps while the preforming is pressed, so that all layers of fiber cloths in the whole preforming blank body formed after cooling are tightly and uniformly bonded, the preforming blank body prepared by the method is a whole body bonded together instead of being stacked in a dispersing way, and when the preforming blank body is used for HP-RTM, high-pressure resin is injected from the direction vertical to the surface of the fiber cloths, and the preforming blank body cannot be scattered and deformed due to high-pressure impact. The sizing agent adopted by the invention is thermoplastic resin, the molecules of the thermoplastic resin are chain-shaped and crosslinked, and after cooling and sizing, the thermoplastic resin can be softened again by heating and sizing again. Therefore, after the thermoplastic resin is adopted to shape the multi-layer fiber cloth, the whole preformed blank has good toughness and better rebound resilience. The HP-RTM is heated in the process of injecting the fluid at high pressure, and the thermoplastic resin is melted again due to heating, so that the preformed blank body can be prevented from being deformed, broken and damaged under the impact of the high-pressure fluid of the HP-RTM. The invention does not use thermosetting resin as a sizing agent, and the thermosetting resin is not remelted when being heated again after being heated and cooled again, has higher brittleness and is easy to be broken and damaged under the impact of high-pressure fluid of HP-RTM, thereby leading to the deformation of the preformed blank. And the thermoplastic resin belongs to a derivative of petroleum, is environment-friendly and has little pollution to the environment. The thickness of the existing preformed blank body is not more than 20mm, because the thickness is too thick and is easier to be dispersed by high pressure. The preformed blank has strong high-pressure impact resistance, and can be thicker, so that the product with the thickness of more than or equal to 40mm can be prepared.

In the step (1) of the invention, a powder sprayer can be adopted to spray powder, and the shaping powder is uniformly sprayed on the surface of the fiber cloth.

In the invention, powder spraying can be performed on a whole continuous fiber cloth, and then the fiber cloth is subjected to technological operations such as cutting, perforating, breaking and the like by using a cutting machine according to the product size and the mould requirement after the powder spraying is finished, as shown in figure 1.

In the invention, the specific selection of the sizing agent can be selected by comprehensively considering the sizing effect and the high-pressure fluid performance in the subsequent HP-RTM, and the sizing agent which has good sizing property, high matching degree with the high-pressure fluid in the HP-RTM and does not react with the high-pressure fluid chemically is preferable.

Illustratively, the shaping powder is at least one of polypropylene resin, polyamide resin, polyester resin, polyphenylene oxide resin, and polystyrene. The shaping powder can also be a modified product of the above materials.

In the invention, the dosage of the sizing powder is 8-12g/m ² for further improving the sizing effect of the sizing agent and resisting high-pressure fluid impact. For example 9g/m ²、10g/m²、11g/m².

In order to enable stacking of a plurality of fiber cloths to be tidy, the step (2) of stacking the plurality of fiber cloths comprises the following steps: marking is made at the center point of each layer of fiber cloth, marking is also made at the middle part of the stacking tool, the marking points of the fiber cloth and the marking points of the tool are overlapped, and each layer of fiber cloth is stacked and placed. The central mark point mode can prevent the scattering of a plurality of fiber cloths.

Illustratively, the fiber cloth is at least one of glass fiber, carbon fiber, basalt fiber, aramid fiber, and plant fiber.

Illustratively, the fiber cloth is woven in at least one of a unidirectional cloth, a checkered cloth, a mesh cloth, a warp knitted cloth, and an axial cloth.

In the step (2), the heating function is to melt, permeate and flow the shaping powder in the fiber cloth, and the heating temperature can be determined according to the melting temperature of the shaping powder.

Illustratively, in step (2), the heating is at a temperature of 120-180 ℃.

Illustratively, in step (2), the heating is at least one of infrared heating, contact heating, and microwave resonance heating.

In the step (2) of the present invention, the pressurizing is performed to preform the fiber cloth and to more uniformly infiltrate the molding powder in a molten state into the fiber gaps.

Illustratively, in step (2), the pressurized pressure is in the range of 1000KN to 5000KN.

In the step (3) of the invention, the cooling function is to take away the heat in the preformed blank, and the shaping powder is changed from a liquid state to a solid state due to the temperature reduction and is solidified in the fiber cloth, so that the fiber cloths in different layers are tightly connected together, the original dispersed fiber cloths are combined into a whole, and the phenomena of deflection, damage and the like of the preformed blank caused by high-pressure impact can be avoided.

Illustratively, the cooling is by passing a cooling liquid into the preform mold to remove heat from the preform body.

Illustratively, the method further comprises: cutting, trimming and punching the preformed blank body obtained in the step (3).

Illustratively, the preformed blanks of the present invention have a thickness of ≡40mm.

Illustratively, the preform body is cut by one or more of vibration cutting, laser cutting, ultrasonic cutting, and high pressure water cutting. Further preferably, the cutting means is ultrasonic cutting. Ultrasonic cutting is more suitable for cutting thicker preform blanks.

Specifically, in the blank cutting, the conditions for using ultrasonic cutting are: the air supply pressure is 6-8bar, the amplitude is 37-42%, and the cutting speed is 20-60mm/s.

Ultrasonic cutting technology refers to the conversion of current into electric energy by an ultrasonic generator, the converted high-frequency electric energy is converted into mechanical vibration with the same frequency again by a transducer, and then the mechanical vibration is transmitted to a cutting knife by a set of amplitude modulator device capable of changing amplitude. The cutter transmits the received vibration energy to the cutting surface of the workpiece to be cut, and the blank body is cut.

The air supply pressure is 6-8bar to ensure sufficient air quantity, and the cutter can be cooled in time to prolong the service life. The amplitude of the cutter is kept within the range of 37-42%, which is beneficial to the blank body to be cut effectively, and meanwhile, the cutter is not damaged due to excessive vibration. The cutting speed is 20-60mm/s, so that the cut is smooth and firm, the edge cutting is accurate, the deformation is avoided, the edge curling, fuzzing, spinning, wrinkling and the like are avoided. In addition, the cutter point and the ground always keep 90 degrees during cutting, the cutting path always keeps parallel to the outer edge of the die, the shape error of the blank in the cutting process can be reduced, and the complete high-quality blank is cut.

The invention adopts the ultrasonic cutting knife, can cut out the complete high-quality green body rapidly and efficiently by optimizing the amplitude, speed, cutting angle and path of the knife, improves the efficiency, and can produce the product with complex structure and thickness of more than or equal to 40mm by combining the preforming process steps.

Specifically, the pressed preform body is placed on a cutting tool, and the preform body is fastened on the cutting tool by bolt fastening. And cutting, trimming, punching and the like are performed on the preformed blank body in a cutting mode according to the actual size and redundancy condition of the blank body.

Cutting the preformed blank into a plurality of blanks, and improving the manufacturing efficiency of the blanks.

In a second aspect, the invention also provides a preformed blank obtained by the method.

The preform body is a coherent whole and not a discrete stack. Has stronger impact resistance. The preformed blank body can be thicker, and the product with the thickness more than or equal to 40mm can be prepared. And the shaping powder in the preformed blank is thermoplastic resin, so that the whole preformed blank has good toughness, better rebound resilience and good shaping.

Applying the preformed blank to HP-RTM, and injecting high-pressure resin from the direction vertical to the surface of the fiber cloth, wherein the preformed blank cannot be scattered and deformed due to high-pressure impact; the HP-RTM has a heating process in the process of injecting the fluid at high pressure, and the thermoplastic resin is melted again due to heating, so that the preformed blank body can be prevented from being deformed, broken and damaged under the impact of the high-pressure fluid of the HP-RTM.

The invention also provides a rapid forming die for the HP-RTM of the composite material component, which is used for realizing the application of the preformed blank in the HP-RTM, namely, the die is adopted when the preformed blank is applied in the HP-RTM.

A composite component HP-RTM rapid prototyping die comprising: the upper die 100, the lower die 200, the vacuumizing system 110, the sealing glue sealing structure 206, the air sealing structure 207, the temperature control system and the pressure control system, wherein the upper die 100 and the lower die 200 form a cavity 300;

the upper die 100 is provided with a vacuum control valve mounting port, and the cavity 300 is connected with the vacuumizing system 110 through a vacuum control valve 114 in the vacuum control valve mounting port;

The vacuum control valve 114 is provided with a high temperature resistant O-ring 1141 and a conical mechanical seal.

Specifically, the vacuum control valve includes a valve stem 1143 and a valve housing 1142, the valve stem 1143 and the valve housing 1142 forming a tapered mechanical seal.

In one possible implementation, the valve stem 1143 includes a first constant diameter section, a curvilinear section, and a second constant diameter section that are connected in sequence. The inner wall of valve housing 1142 includes a first constant diameter section, a curved section and a second constant diameter section that decrease in diameter and meet in sequence. The valve sleeve 1142 is sleeved on the valve rod 1143, a first constant diameter section of the valve rod 1143 is in clearance fit with a first constant diameter section of the inner wall of the valve sleeve 1142, a curved section of the valve rod 1143 is in transition fit with a curved section of the inner wall of the valve sleeve 1142, and a second constant diameter section of the valve rod 1143 is in transition fit with a second constant diameter section of the inner wall of the valve sleeve 1142.

In the invention, the mold is required to be vacuumized after being closed and pressurized, and the cavity 300 is connected with the vacuumizing system 110 through the vacuum control valve 114 in the vacuum control valve mounting port. In order to facilitate vacuumizing, a gap at the end part of the cavity is smaller than a gap in the middle of the cavity along the flowing direction of the resin, a horizontal opening end is arranged at the end part of the cavity at one end of the vacuum control valve, and compared with the end part of the cavity at the front end of the vacuum control valve, an expanding section is arranged at the horizontal opening end, so that the flow of vacuumizing airflow is facilitated, the vacuumizing efficiency is improved, and a higher vacuum rate is obtained.

The vacuum control valve mounting port is provided in the upper mold 100 in the region of the horizontal mating sections of the upper mold 100 and the lower mold 200 at the end of the cavity 300. Considering that the cavity 300 has a preform accommodating space and provides a resin flowing mold filling space, the HP-RTM process has a larger mold closing gap and a higher injection pressure, and the adopted low viscosity resin has the characteristic of high injection flow rate, in order to realize vacuumizing and effectively control the speed of pressurized injection resin, the possibility that the resin enters the vacuum control valve is reduced as much as possible, the horizontal length of the horizontal opening end of the cavity end is greater than the wall thickness of the second equivalent diameter section of the valve sleeve 1142, but less than the sum of the wall thickness of the second equivalent diameter section of the valve sleeve 1142 and the diameter of the second equivalent diameter section of the valve rod 1143, and the matching gap of the valve sleeve 1142 and the valve rod 1143 is not completely located in the horizontal area of the horizontal opening end of the cavity end.

Because the mating clearance portion of the valve housing 1142 and the valve stem 1143 is located in the horizontal region of the horizontal open end of the cavity end, the mold seal structure is damaged in order to further avoid the resin from entering the vacuum control valve, causing blockage of the mold injection port and the vacuum port. The vacuum control valve of the invention also comprises a high temperature resistant O-shaped sealing ring.

The number of high temperature resistant O-rings is plural, in one possible embodiment, the mating surfaces of the valve housing 1142 and the valve stem 1143 are provided with three sets of high temperature resistant O-rings 1141, the first set and the second set of high temperature resistant O-rings 1141 are located in the second equal diameter section of the valve stem 1143 and the second equal diameter section of the inner wall of the valve housing 1142, and the third set of high temperature resistant O-rings 1141 are located in the curved section of the valve stem 1143 and the curved section of the inner wall of the valve housing 1142.

Specifically, the first constant diameter section, the curve section and the second constant diameter section of the valve rod 1143 are respectively provided with a sealing ring mounting groove, and the high temperature resistant O-shaped sealing ring is arranged in the sealing ring mounting groove.

Because the cavity is formed by the cooperation of the upper die and the lower die, in order to facilitate vacuumizing, one side wall of the vacuum control valve mounting port is flush with the edge of the horizontal opening end of the end part of the cavity, and the valve sleeve 1142 is in transition fit with the upper die core 104 of the upper die. In order to prevent resin from entering the matching surface of the valve sleeve 1142 and the upper die core 104 of the upper die, a high-temperature-resistant O-shaped sealing ring 1141 is arranged between the valve sleeve 1142 and the upper die core 104, a sealing ring mounting groove is formed in the outer surface of the valve sleeve 1142, and the high-temperature-resistant O-shaped sealing ring 1141 is mounted in the sealing ring mounting groove.

The invention is provided with four groups of high-temperature-resistant O-shaped sealing rings 1141, the three groups of high-temperature-resistant O-shaped sealing rings are sequentially sleeved on a valve rod 1143 along the axial direction of the valve rod 1143, wherein the first group of high-temperature-resistant O-shaped sealing rings 1141 and the second group of high-temperature-resistant O-shaped sealing rings 1141 are arranged at the cylindrical matching surface part of the second equal-diameter section, and the third group of high-temperature-resistant O-shaped sealing rings 1141 are arranged at the conical matching surface part of the curve section; the fourth set is disposed on the mating surface between the valve housing 1142 and the upper core 104 of the upper mold.

In order to further improve the sealing performance, along the axial direction of the valve rod 1143, the intervals among the first group of high-temperature-resistant O-shaped sealing rings, the second group of high-temperature-resistant O-shaped sealing rings and the third group of high-temperature-resistant O-shaped sealing rings are gradually increased, the fourth group of high-temperature-resistant O-shaped sealing rings are positioned between the second group of high-temperature-resistant O-shaped sealing rings and the third group of high-temperature-resistant O-shaped sealing rings, and the second group of high-temperature-resistant O-shaped sealing rings and the fourth group of high-temperature-resistant O-shaped sealing rings are partially overlapped in the axial direction.

In order to further improve the sealing performance, the following relationship exists among the spaces among the first group of high-temperature-resistant O-shaped sealing rings, the second group of high-temperature-resistant O-shaped sealing rings and the third group of high-temperature-resistant O-shaped sealing rings: the first group of high temperature resistant O-shaped sealing rings are arranged at the cylindrical matching surface part of the second equal diameter section of the valve rod 1143, 1/2 part of the length of the second equal diameter section from bottom to top (the measurement standard is the length of the second equal diameter section of the valve rod 1143, the starting point is the lower end surface), the second group of high temperature resistant O-shaped sealing rings are arranged at the 3/4 part of the length of the second equal diameter section from bottom to top (the measurement standard is the length of the second equal diameter section of the valve rod 1143, the starting point is the lower end surface), the third group of high temperature resistant O-shaped sealing rings 1141 are arranged at the conical matching surface part of the valve rod 1143, and 1/2 part of the sum of the lengths of the curve section of the valve rod 1143 and the second equal diameter section from bottom to top (the measurement standard is the sum of the lengths of the curve section of the valve rod 1143 and the second equal diameter section, the starting point is the lower end surface), and the fourth group of high temperature resistant O-shaped sealing rings are arranged at the matching surface part of the valve sleeve 1142 and the upper die core 104 of the upper die. The dimensions of the first group of high-temperature-resistant O-shaped sealing rings, the second group of high-temperature-resistant O-shaped sealing rings, the third group of high-temperature-resistant O-shaped sealing rings and the fourth group of high-temperature-resistant O-shaped sealing rings meet the standardized requirements.

Through the structural design, in the molding cycle production of the invention, the sealing structure of the mold is not easy to damage, so that vacuum failure is avoided, and the service life of the mold is effectively prolonged.

Compared with the existing die, the invention seals the vacuum control valve in a metal mechanical seal and high-temperature resistant seal ring mode, so that the service life of the die is effectively prolonged, and the die repairing times in batch production are reduced.

It should be noted that, according to the particularity of the HP-RTM molding process, the service life of the mold sealing structure directly affects the cycle service life of the mold, the resin is in a liquid state before curing, and becomes a solid state after curing, in actual production, the existing sealing structure easily causes damage to the sealing ring or causes the resin to adhere to the mechanical sealing part, and in subsequent cyclic production, failure of the vacuum system easily occurs, so that the whole vacuum system is filled with the resin, and irreversible damage is brought to the mold and equipment. To above-mentioned problem, from down upwards, vacuum control valve position sets up four high temperature resistant O type sealing washer and toper mechanical seal, and every seal structure of group all plays isolated resin and sealed function, effectively prevents that glue overflow and gas leakage scheduling problem from appearing, and current a set of seal structure inefficacy back, the multiunit seal structure at the back can continue to keep effective state, makes production cycle go on incessantly, can effectually improve the life of mould.

Specifically, the sealing structure 206 is disposed on the parting surface of the lower mold core 104 and is located outside the cavity. The airtight seal 207 structure is arranged outside the sealing structure 206, and the sealing structure 206 and the airtight seal 207 structure are sequentially arranged at one side close to the edge of the die, namely, the outer side of the horizontal opening end of the die cavity.

Specifically, the ends of the upper die 100 and the lower die 200 are matched through steps, and the air seal 207 structure is positioned at the step matching surface of the upper die 100 and the lower die 200.

The sealing structure plays a role in sealing vacuum, and the air sealing structure can effectively form a secondary sealing space, so that the whole cavity 300 space is more reliable.

Further, the upper mold 100 includes an upper mold fixing plate 101, an upper mold cushion block 102, an upper mold heat insulation plate 103, an upper mold core 104, an upper mold heat insulation plate 105, an injection port 107, and a guide sleeve 109.

The upper die cushion block 102 is connected with the upper die fixing plate 101, the upper die core 104 is connected with the other side of the upper die cushion block 102, the upper die heat insulation plate 103 is arranged between the upper die core 104 and the upper die cushion block 102, the upper die heat insulation plate 105 is coated on the periphery of the upper die core 104, the injection port 107 is connected with the upper die core 104, the bottom end face of the injection port 107 is level with the lower end face of the upper die core 104, the guide sleeve 109 is connected with the upper die core 104, and the guide sleeve 209 is concentric with the guide pillar 209. The matching gap between the injection port 107 and the injection nozzle of the HP-RTM high-pressure injection molding equipment is sealed by a high-temperature-resistant O-shaped sealing ring.

Further, the lower die 200 includes a lower die fixing plate 201, a lower die cushion block 202, a lower die heat insulation plate 203, a lower die core 204, a lower die heat insulation plate 205, a supporting block 208, and a guide pillar 209.

The lower die cushion block 202 is connected with the lower die fixing plate 201, the other end of the lower die cushion block 202 is connected with the lower die core 204, the lower die heat insulation plate 203 is arranged between the lower die cushion block 202 and the lower die core 204, the lower die heat insulation plate 205 is connected with the lower die core 204 and is coated on the outer side of the lower die core 204, the supporting block 208 is connected with the upper end face of the lower die core 204, the guide pillar 209 is connected with the upper end face of the lower die core 204 and is concentric with the guide sleeve 109.

Specifically, the temperature control system comprises an upper die temperature control system and a lower die temperature control system; the upper die temperature control system includes an upper die temperature controller 120 and an upper die temperature sensor 108.

Specifically, the mold further includes a pressure control system including a pressure sensor 106.

Specifically, the length of the upper mold core 104 is a, and the upper mold temperature sensor 108 is connected to the side of the upper mold core 104 and is disposed in the upper mold coreWhere/>Where/>A place; the upper mold temperature controller 120 is located inside the upper mold core 104 and is communicated with the side surface of the upper mold core 104.

Specifically, the length of the lower mold core 204 is the same as the length of the upper mold core 104, and the lower mold temperature sensor 214 is connected to the outer side of the lower mold core 204 and is disposed in the lower mold coreWhere/>Where/>A place; the lower mold temperature controller 220 is located inside the lower mold core 204 and is communicated with the outer side of the lower mold core 204.

Specifically, the pressure sensor 106 is disposed at the connection between the two ends of the upper mold core 104 and the cavity 300, and the pressure sensor 106 is connected to the upper mold core 104 and is aligned with the upper surface of the cavity 300.

The temperature control system and the pressure control system can effectively feed back the data of pressure change in the whole molding process of injecting thermosetting resin into the mold cavity and the data of temperature change of the mold before and after curing the resin, and adjust the injection pressure and the mold temperature by combining the whole quality data of the test sample, so that the test period of the qualified sample can be effectively reduced, and the production cost of products can be effectively reduced.

Specifically, the lower die 200 includes an ejection mechanism 210, the ejection mechanism 210 is composed of a push plate 211, a push rod 212 and an ejection cylinder 213, the push rod 212 is provided with two high-temperature-resistant O-shaped sealing rings, and the two high-temperature-resistant O-shaped sealing rings are sequentially arranged at a position below the ejection height of the push rod.

In order to enable the resin products to be synchronously and automatically ejected, the number and the position of the ejector rods are required to meet certain conditions. Specifically, the number of the ejector pins 212 is four, and the ejector pins are respectively disposed in the lower mold coreWhere/>Where/>Where/>The ejector rod 212 is fixedly connected with the push plate 211, four ends of the push plate 211 are respectively provided with one ejection oil cylinder 213, one end of each ejection oil cylinder 213 is fixedly connected with the push plate 211, the other end of each ejection oil cylinder 213 is fixedly connected with the lower die fixing plate 201, and oil paths of the four ejection oil cylinders 213 are connected in series.

It should be noted that, when the ejection cylinder 213 ejects, the ejector rods 212 synchronously eject, so that the product is stably ejected, and the situation that the product is damaged due to the asynchronous ejection of the ejector rods 212, or one end of the product ejects and the other end is blocked in the cavity 300 is avoided, and the ejector rods 212 synchronously eject to enable the production process to be more stable and reliable, so that the defective product rate is reduced.

The composite material component prepared by the HP-RTM rapid forming die provided by the invention has the advantages of shorter forming period, higher forming efficiency, lower manufacturing cost and smooth double surfaces of products, and meanwhile, the preformed blank provided by the invention can be used for preparing products with the thickness of more than or equal to 40 mm.

The preformed blank of the invention can be used for preparing plate springs by an HP-RTM method, battery shells, front covers and the like by the HP-RTM method, and has wide application range.

The preformed blank for HP-RTM and the method of making the same according to the present invention are further illustrated by the following specific examples.

Example 1

A method of making a preform for HP-RTM production of leaf springs, comprising:

HP-RTM composite leaf spring preform

And selecting unidirectional glass fiber cloth and carbon fiber cloth to manufacture the plate spring preform according to the layering design result.

1. Spraying sizing powder (modified polypropylene resin) matched with epoxy resin on the surfaces of the glass fiber unidirectional cloth and the carbon fiber cloth according to the dosage of 9g/m ²;

2. cutting the glass fiber cloth sprayed with the shaping powder on a cutting machine, wherein the cutting size is 1300mm, 20 layers of glass fiber unidirectional cloth with the same size are cut in total, and 2 layers of carbon fiber unidirectional cloth (the middle point of each layer of carbon fiber cloth is marked) with the same size are cut with 650 mm;

3. Firstly, 10 layers of cut glass fiber unidirectional cloth are placed on a stacking tool, the middle points of the fiber cloth are aligned with the middle points of the tool, four sides of each layer of cloth are aligned, two layers of carbon fiber cloth are placed on the 10 layers of glass fiber unidirectional cloth, the middle points of all the fiber cloth are required to be aligned with the middle points of the tool, long sides of the carbon fiber cloth are required to be aligned with long sides of the glass fiber cloth, then 10 layers of glass fiber cloth are placed, the middle points of the glass fiber cloth are aligned with the middle points of the tool, and four sides of the glass fiber cloth are required to be aligned with the glass fiber cloth placed on the bottom layer;

4. Placing the laminated carbon fiber/glass fiber cloth into a pre-forming die, setting the die temperature to be 150 ℃, setting the pressure to be 5000KN, pressing the carbon fiber/glass fiber cloth to have a thickness of 40mm, starting cooling after 20 minutes of pressing, and opening a press after the temperature is reduced to 80 ℃, and taking out a pre-formed blank;

5. Placing the taken out preformed blank on a cutting tool, compacting the blank by adopting a two-section fastening mode, then adopting ultrasonic cutting equipment, wherein the air supply pressure is 6bar, the amplitude is 40%, the cutting speed is 20mm/s, the cutting power is 200w, the cutting frequency is 20000HZ, cutting the blank into preformed blanks with the width of 70mm, and trimming and punching the blank.

Example 2

A method of preparing a preform for HP-RTM preparation of a battery housing, comprising:

1. Spraying shaping powder (modified polypropylene resin) on the surfaces of glass fiber and carbon fiber cloth according to the dosage of 11g/m ²;

2. Cutting the glass fiber cloth into square cloth with the size of 1200mm or 900mm by using a cutting machine, and cutting the 4 corners inwards by adopting a 45-degree angle cutting mode at the right angle position of the cloth to form a total of 4 layers; cutting 800mm x 800m carbon fiber axial cloth into one layer;

3. Using a clamping tool to stack 5 layers of cloth together according to the sequence of (glass fiber/carbon fiber/glass fiber) by adopting a stacking tool and a midpoint alignment method, and placing the carbon fiber cloth at the right middle position of the glass fiber cloth;

4. Placing the five-layer fiber cloth in a preforming die by using a clamping device, heating the preforming die to 140 ℃, and preserving heat for 30min, wherein the pressure is 3000KN;

5. And after heat preservation is finished, taking out the preformed blank, placing the preformed blank on the surface of a cutting tool, cutting the periphery of the blank by using a 500HZ vibrating tungsten steel knife, removing the outer flash of the tool, cutting and punching the raised part on the upper surface of the blank by using the vibrating tungsten steel knife, and leaving the blank for later use after removing the redundant part.

Example 3

A method of preparing a preform for an HP-RTM preparation front cover, comprising:

1. Based on the environmental protection and design requirements, basalt fiber warp knitted cloth and bamboo fiber unidirectional cloth are selected as main knitted cloth. Uniformly spraying sizing powder (modified polyamide resin) on the surface of the fiber cloth by adopting a powder sprayer according to the dosage of 12g/m ²;

2. cutting basalt fiber warp knitted cloth into a semicircular arc structure with the thickness of 1000mm being 600mm by adopting a fiber cloth cutting machine, and cutting 6 layers in total; cutting bamboo fiber check cloth into strips with the length of 1000mm and 50mm, and cutting 4 layers in total;

3. Adopting a stacking tool, firstly placing 3 layers of basalt fiber cloth, placing 4 layers of bamboo fiber cloth on the bottom edge of the basalt fiber cloth, and then placing 3 layers of basalt fiber cloth;

4. Placing the stacked fiber cloth in a large microwave heating box for microwave heating treatment, heating for 5min with 20000W power, rapidly transferring to a cover pre-forming die at the final temperature of 160 ℃, pressing into a pre-forming blank (rough blank), and cooling;

5. transferring the pressed preformed blank to a cutting tool, setting laser cutting power to 10KW and cutting speed to 10m/min by adopting a laser cutting mode, and removing redundant flash and redundant parts of the preformed blank.

Example 4

A preform was prepared as in example 1, except that the sizing powder was used in an amount of 2g/m ².

Example 5

A preform was prepared as in example 1, except that the pressing pressure was 900KN.

Comparative example 1

A preform was prepared as in example 1, except that a thermosetting resin (epoxy resin) was used instead of a thermoplastic resin (polypropylene resin).

Test case

HP-RTM molding was performed using the preform bodies of examples 1-5 and comparative example 1. The results are shown in Table 1.

TABLE 1

As can be seen from the comparison of the results of example 1 and comparative example 1, the shaping effect of the preform body using the thermoplastic shaping powder is better; from the examples 1-3, the preparation method of the invention is applicable to the preparation of preformed blanks in a plurality of fields and has wide application range; as can be seen from a comparison of example 1 with examples 4-5, a preform having a better setting effect can be obtained by using the setting powder of the present invention in an amount and under a pressurized pressure.

Example 6

A method for rapidly forming a composite material component HP-RTM for the preparation of a composite material leaf spring, the process flow comprising the steps of:

(1) The required resin amount is 2100g through simulation calculation, and the pressure of each component of the glue injection head is adjusted to 140bar; preheating HUNTSMAN 3585 epoxy resin, HUNTSMAN 3831 amine curing agent and internal mold release agent, vacuumizing and defoaming, wherein the temperature of the resin is 80 ℃, the temperature of the curing agent is 40 ℃ and the temperature of the internal mold release agent is 28 ℃; the glue mixer is adjusted to a small flow circulation mode;

(2) Cleaning impurities on the surface of a die, starting a press, and opening the die; uniformly coating an external release agent CLE-705 on the surface of a die for a small number of times, wherein the dosage of each time is 15ml, and heating the die to 90 ℃;

(3) Preparing a plate spring preformed blank according to the method of the embodiment 1, wherein the carbon fiber cloth is adopted, 34 layers of cut fiber cloth are adopted, the single-layer thickness is 1.2mm, the thickness of the preformed blank is 40mm, the air supply pressure of ultrasonic cutting is 0.65MPa, the amplitude is 42%, the cutting speed is 20mm/s, the cutter point and the ground are always kept at 90 degrees, the cutting path is always kept parallel to the outer edge of a die, and the cut blank is transferred to the forming die;

(4) Applying a clamping force 9000kN after the press is clamped and locked;

(5) Opening a vacuum control valve to vacuumize for 5min;

(6) And (5) after the vacuumizing is finished, closing the vacuum control valve. The glue mixer is adjusted to a high-pressure circulation mode, and HUNTSMAN 3585 epoxy resin, HUNTSMAN 3831 amine curing agent and QZ12-IRA release agent are mixed according to the mass ratio of 100:24: after being uniformly mixed, 0.5 is injected onto fiber cloth in a mould through a glue injection head arranged in the mould according to the set injection flow rate of 70g/s and the injection time of 30 s;

(7) Pressure maintaining and curing for 5min to enable the resin to be rapidly cured and molded; after the curing process is finished, unloading pressure, opening a vacuum control valve to break the vacuum environment, and opening the die; and taking out the product after die opening, cooling and removing flash to obtain the composite plate spring component with the thickness of 40 mm.

TABLE 2 comparison of inventive example 6 with prior art molding data

Project	Example 6	Existing prepreg molding technology
			Single piece production cycle	20min	120min
Shaping efficiency	High height	Low and low
			Cost of product	Leaf spring member 120 element/root	Leaf spring member 400 element/root
Product thickness	40mm	≤20mm

The present invention is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present invention are intended to be included in the scope of the present invention.

Claims

1. A method of making a preform for HP-RTM, the method comprising:

2. The method according to claim 1, wherein the setting powder is at least one of polypropylene resin, polyamide resin, polyester resin, polyphenylene oxide resin, and polystyrene.

3. The method according to claim 1, wherein the shaping powder is used in an amount of 8-12g/m ².

4. The method of claim 1, wherein in step (2), the palletizing the plurality of fiber cloths comprises: marking at the middle point of each layer of fiber cloth, marking at the middle part of the stacking tool, overlapping the marking point of the fiber cloth and the marking point of the tool, and stacking and placing the fiber cloth layers.

5. The method of claim 1, wherein in step (2), the heating is at a temperature of 120-180 ℃.

6. The method of claim 5, wherein in step (2), the pressurized pressure is 1000KN-5000KN.

7. The method of claim 5, wherein in step (2), the heating is performed by at least one of infrared heating, contact heating, and microwave resonance heating.

8. The method according to claim 1, wherein the method further comprises: cutting, trimming and punching the preformed blank body obtained in the step (3).

9. Preform body obtainable by a method according to any one of claims 1-8.

10. Use of the preform body according to claim 9 in HP-RTM.