CN-121973367-A - Heating and melting multilayer mould pressing device for fiber reinforced thermoplastic composite material

CN121973367ACN 121973367 ACN121973367 ACN 121973367ACN-121973367-A

Abstract

The invention relates to the technical field of composite materials, in particular to a fiber reinforced thermoplastic composite material heating and melting multilayer mould pressing device which comprises an upper mould and a lower mould, wherein a plurality of ejection assemblies for ejecting a formed mould from the lower mould are arranged in the lower mould, distance sensors are arranged on the ejection assemblies, ejection assemblies are symmetrically arranged on two sides in the lower mould, each ejection assembly comprises a hydraulic cylinder and a push rod, the bottom ends of the push rods are fixedly connected to the output end of the hydraulic cylinder, a plurality of spray holes are axially formed in the push rod, the diameters of the spray holes are sequentially increased from top to bottom, input holes communicated with the ejection assemblies are formed in the lower part of the push rod, and the top walls of the push rods are pneumatic diaphragms. The invention provides micro demoulding force through air pressure and drives the pneumatic diaphragm to vibrate to generate a collaborative demoulding mechanism, thereby realizing low-damage demoulding of products with complex structures.

Inventors

SONG WENZHE
FAN CONGZE
HU ZHENXIN
CHEN YIWEI
ZHENG JINGHUA
WU JIAN

Assignees

南京航空航天大学
天津市天锻压力机有限公司

Dates

Publication Date: 20260505
Application Date: 20260128

Claims (10)

1. The device for heating and melting the multi-layer mould pressing of the fiber reinforced thermoplastic composite material comprises an upper mould (1) and a lower mould (4), and is characterized in that a plurality of ejection assemblies for ejecting a formed mould from the lower mould (4) are arranged in the lower mould (4), distance sensors are arranged on the ejection assemblies, ejection assemblies for ejecting high-pressure gas to separate the mould are symmetrically arranged on two sides in the lower mould (4), each ejection assembly comprises a hydraulic cylinder (8) and a push rod (10), the bottom ends of the push rods (10) are fixedly connected to the output end of the hydraulic cylinders (8), a plurality of spray holes (11) are axially formed in the push rods (10), the diameters of the spray holes (11) are sequentially increased from top to bottom, input holes (12) communicated with the ejection assemblies are formed in the lower parts of the push rods (10), and the top walls of the push rods (10) are pneumatic membranes (9).
2. The device for heating, melting and multi-layer molding of fiber reinforced thermoplastic composite material according to claim 1, wherein piezoelectric ceramic actuators (13) are also arranged in the ejector rods (10).
3. The device for heating and melting the multi-layer molding of the fiber reinforced thermoplastic composite material according to claim 1, wherein the top of the pneumatic diaphragm (9) is fixedly connected with a high-temperature-resistant elastic gasket (3).
4. The device for heating and melting the multi-layer molding of the fiber reinforced thermoplastic composite material according to claim 1, wherein the injection assemblies comprise gas distribution cavities (7) and gas sources symmetrically arranged in the lower die (4), the output ends of the gas sources are communicated with the input ends of the gas distribution cavities (7), the output ends of the gas distribution cavities (7) are communicated with a plurality of gas transmission pipelines (6), and the other ends of the gas transmission pipelines (6) far away from the gas distribution cavities (7) are communicated with the input holes (12).
5. A fibre reinforced thermoplastic composite material heated and melted multilayer mould pressing device according to claim 1, characterized in that heating elements (5) are arranged in both the upper mould (1) and the lower mould (4).
6. The device for hot-melt multi-layer molding of fiber-reinforced thermoplastic composite material according to claim 1, wherein the surfaces of the upper die (1) and the lower die (4) of the mold (2) are coated with a release coating.
7. A device for hot melt multi-layer molding of fiber reinforced thermoplastic composite material according to claim 6, wherein the bottom of the lower mold (4) is provided with a cooling channel, which is connected to an external cooling system.
8. The device for heating and melting the multi-layer mould pressing of the fiber reinforced thermoplastic composite material according to claim 2, wherein buffer springs (14) are arranged between the pneumatic diaphragm (9) and the elastic gasket (3), and the buffer springs (14) are uniformly distributed along the axial direction of the ejector rod (10).
9. A fiber reinforced thermoplastic composite material heating-melting multilayer molding apparatus as claimed in claim 1, wherein the vibration frequency range of the piezoelectric ceramic actuator (13) is 20-50kHz, and the periphery of the piezoelectric ceramic actuator (13) is provided with a heat-insulating mica sheet.
10. The fiber reinforced thermoplastic composite heated and melted multi-layer molding apparatus of claim 1, wherein the control system comprises: The acquisition module is in signal connection with the distance sensor and is used for receiving the model distance data transmitted by the distance sensor, generating digital distance data by adopting an analog-digital conversion mode and transmitting the digital distance data to the processing module; The processing module is used for receiving the digital distance data, generating a control instruction by adopting a preset algorithm and transmitting the control instruction to the control module; The control module is used for receiving a control instruction, generating a control signal of the hydraulic cylinder (8) by adopting a pulse width modulation mode and transmitting the control signal to the hydraulic cylinder (8), receiving the control instruction, generating a gas injection signal by adopting a switch control mode and transmitting the gas injection signal to the gas distribution cavity (7), receiving the control instruction, generating a vibration control signal by adopting a frequency modulation mode and transmitting the vibration control signal to the piezoelectric ceramic actuator (13); The temperature regulation module is in signal connection with the heating element (5), and is used for receiving temperature data transmitted by the heating element (5), generating a temperature regulation signal by adopting a PID control mode and transmitting the temperature regulation signal to the heating element (5).

Description

Heating and melting multilayer mould pressing device for fiber reinforced thermoplastic composite material Technical Field The invention relates to the technical field of composite materials, in particular to a heating and melting multi-layer mould pressing device for a fiber reinforced thermoplastic composite material. Background The heating and melting multilayer molding process of thermoplastic composite material is one kind of advanced composite material forming technology. The process typically involves stacking multiple layers of prepregs or preforms in a mold, melting and plasticizing the thermoplastic resin matrix therein by external heating, and then cooling and solidifying under pressure to finally obtain a part having a specific shape and properties. The process integrates material compounding and product forming, is particularly suitable for preparing structural members with complex geometric shapes, high specific strength and recoverable values, and has wide application prospects in the fields of aerospace, automobile weight reduction and the like. However, this process presents significant challenges in the demolding step. Because the thermoplastic composite material has higher viscosity in a high-temperature melting state, stronger adhesion force can be generated between the thermoplastic composite material and the surface of a die, and meanwhile, a vacuum negative pressure area can be formed in the die pressing process, so that the die stripping resistance is huge. The traditional demolding mode mainly depends on mechanical pushing of the ejector rod or single air pressure assistance, and has obvious defects that the demolding force provided by the mechanical ejector rod is too concentrated, top marks are easily left on the surface of a product to influence the appearance and the surface quality, and even for products with thin walls or complex structures such as deep cavities, inverted buckles and the like, the uneven ejection force can cause irreversible deformation, tearing or internal damage of the product at the demolding moment, so that the product quality and the production yield are severely restricted. Therefore, there is a need to provide a novel molding apparatus that provides uniform, controllable, low-damage mold release force. Disclosure of Invention In order to solve the problems, the invention discloses a fiber reinforced thermoplastic composite material heating and melting multi-layer mould pressing device which provides micro demoulding force through air pressure and drives a pneumatic diaphragm to vibrate to generate a collaborative demoulding mechanism so as to realize low-damage demoulding of a product with a complex structure. In order to achieve the aim, the technical scheme of the invention is that the device for heating and melting the multi-layer mould pressing of the fiber reinforced thermoplastic composite material comprises an upper mould and a lower mould, wherein a plurality of ejection assemblies for ejecting a formed mould from the lower mould are arranged in the lower mould, distance sensors are arranged on the ejection assemblies, and injection assemblies for ejecting high-pressure gas to separate the mould are symmetrically arranged on two sides in the lower mould; The ejection assembly comprises a hydraulic cylinder and an ejector rod, the bottom end of the ejector rod is fixedly connected to the output end of the hydraulic cylinder, a plurality of spray holes are axially formed in the ejector rod, the diameters of the spray holes are sequentially increased from top to bottom, input holes communicated with the ejection assembly are formed in the lower portion of the ejector rod, and the top wall of the ejector rod is a pneumatic diaphragm. The technical principle of the scheme is as follows: When the demolding process starts, each ejection assembly feeds back ejection displacement in real time through a distance sensor, and a control system presets ejection sequence and pressure of each region according to the shape of a product, such as ejection of a deep cavity region first and ejection of a chamfer step by step. For example, for products with a ladder-shaped structure, the control system can instruct the bottom ejector rod to eject a certain distance, and coordinate the ejector rods in other areas to synchronously act after the upper structure is loosened, so that the cracking of the products caused by uneven ejection is avoided. The control system instructs the spraying assembly to act, high-pressure gas enters the cavity inside the ejector rod through the input hole at the lower part of the ejector rod, and finally is sprayed out from the spraying holes distributed in the axial direction. The high-pressure gas forms a layer of air film between the die cavity and the product, can effectively neutralize partial vacuum adsorption force and surface adhesion force, and provides an initial and uniform separation force for the product, thereby loosening the