CN-121973473-A - Laser-assisted in-situ forming process and device protected by high-temperature inert gas

CN121973473ACN 121973473 ACN121973473 ACN 121973473ACN-121973473-A

Abstract

The invention relates to the technical field of automatic laying of composite materials, in particular to a laser-assisted in-situ forming process and a device under the protection of high-temperature inert gas, wherein the process comprises the steps of supplying a prepreg tape to a laying point; the method comprises the steps of heating a laying point by laser, arranging an inert gas protection cover at the periphery of the laying point, supplying heated inert gas to form local inert atmosphere, forming composite heating by the inert gas through convection heat exchange and laser radiation, and compacting by a compacting roller under the coverage of the protection cover to realize in-situ consolidation. The device comprises a laying head module, a laser heating unit, an inert gas protection cover and an inert gas supply unit. The invention forms stable high-temperature inert protection environment in the laser heating and compacting area, reduces the oxidation and thermal aging risks of the thermoplastic matrix, improves the heating efficiency and the laying speed, realizes the control of a temperature field through the partition air supply, and improves the molding quality and the process stability of the composite material component.

Inventors

CHEN CHENG
HE PENGHUA
LIU WEIPING

Assignees

东华大学

Dates

Publication Date: 20260505
Application Date: 20260312

Claims (10)

1. The laser-assisted in-situ forming process protected by high-temperature inert gas is characterized by comprising the following steps of: S1, feeding and laying materials, namely feeding continuous fiber reinforced thermoplastic and dragging a prepreg tape to a laying point; S2, heating the prepreg tape in the laying point area by adopting laser in an auxiliary manner, so that the thermoplastic matrix reaches a molten or high-elastic state and meets the requirement of in-situ welding; s3, inert gas protection and composite heating, wherein an inert gas protection cover is arranged on the periphery of the laying point, the inert gas protection cover covers an area at least comprising a laser heating area and a compaction area, heated inert gas is supplied into the inert gas protection cover to form local inert atmosphere covering the laying point, and the inert gas forms composite heating with laser heating in the S2 through convection heat exchange; and S4, compacting and in-situ consolidation, namely compacting the compositely heated prepreg tape by a compacting roller under the coverage of the inert gas protection cover to realize in-situ consolidation.
2. The laser-assisted in-situ forming process of claim 1, wherein in S3, the inert gas is nitrogen, argon, carbon dioxide, helium or a mixture thereof.
3. The laser-assisted in-situ forming process of claim 2, wherein in S3, at least two independent temperature control partitions are arranged in the inert gas protection cover along the laying direction, and the temperature control of each partition is realized by independently adjusting the temperature or flow of the inert gas to each partition.
4. A high temperature inert gas shielded laser assisted in situ forming process according to claim 3 wherein said temperature controlled zone includes a melt compaction zone and at least one of a pre-heating zone and a pre-cooling zone, wherein the temperature of the inert gas supplied to said melt compaction zone is controlled to be above ambient temperature and within +30 ℃ of the thermoplastic matrix melt temperature Tm.
5. The laser-assisted in-situ forming process protected by high-temperature inert gas according to claim 1, further comprising S5 monitoring the temperature of the laying point in real time and adjusting the power of the laser and the temperature and flow of the inert gas cooperatively based on the deviation of the monitored temperature from a target temperature; and S6, recovering the inert gas discharged from the inert gas protection cover, and re-supplying the inert gas to the S3 for use after treatment.
6. The laser-assisted in-situ forming device with high-temperature inert gas protection is characterized by comprising a laying head module, a laser heating unit, an inert gas protection cover and an inert gas supply unit, wherein the laying head module comprises a main body of the laying head, a feeding guide mechanism for conveying a continuous fiber reinforced thermoplastic prepreg tape and a compacting roller arranged at the front end of the module; The laser heating module is arranged on one side of the laying head main body, and the outgoing laser beam of the laser heating module is directed to a laying point area in front of and below the compacting roller; The inert gas protection cover is fixedly arranged on the periphery of the laying point and fixedly connected with the main body of the laying head, an air inlet and an air outlet which are communicated with the inert gas supply unit are formed in the wall surface of the inert gas protection cover, an opening is formed in the position corresponding to the path of the laser beam, so that the laser beam passes through and is focused on the laying point, and the compaction roller is arranged in the inert gas protection cover.
7. The laser-assisted in-situ forming device of high temperature inert gas shielding of claim 6, wherein an opening is formed in a wall surface of the inert gas shielding cover near one side of the laser heating unit, and at least one of a flexible sealing skirt, a labyrinth gap structure or a follow-up attaching structure is circumferentially arranged at the lower edge of the inert gas shielding cover so as to reduce leakage loss of the inert gas.
8. The laser-assisted in-situ forming device of claim 7, wherein the inert gas shield is divided into at least two independent chambers by a partition structure, each of the independent chambers is connected with the inert gas supply unit by an independent gas supply branch, and each gas supply branch is provided with a flow controller and a gas heater.
9. The laser-assisted in-situ forming device with high-temperature inert gas protection as claimed in claim 6, further comprising a gas recovery and circulation system, wherein the gas recovery and circulation system is connected with the gas outlet of the inert gas protection cover and the gas inlet end of the inert gas supply unit through pipelines, and the pipelines are provided with a filter for removing impurities and a circulation pump for driving gas circulation.
10. The laser-assisted in-situ forming device with high-temperature inert gas protection as claimed in claim 6, further comprising a temperature monitoring and control system, wherein the temperature monitoring and control system comprises a controller and a thermal infrared imager, the thermal infrared imager is arranged below the laser heating unit and is used for acquiring a temperature field image of a laying point area inside the inert gas protection cover in real time, and the controller is respectively connected with the thermal infrared imager, the laser heating unit and the inert gas supply unit; The controller is configured to generate and output a control signal for synchronously adjusting the laser output power and the temperature and flow of the inert gas to the inert gas protection cover according to the comparison result of the temperature information fed back by the thermal infrared imager and the preset process parameters; The laser heating unit may be replaced with a xenon lamp or an infrared heater.

Description

Laser-assisted in-situ forming process and device protected by high-temperature inert gas Technical Field The invention relates to the technical field of automatic laying of composite materials, in particular to a laser-assisted in-situ forming process and device protected by high-temperature inert gas. Background Continuous fiber reinforced thermoplastic composite materials (CFRTP), such as continuous carbon fiber reinforced polyether ether ketone (CF/PEEK), polyphenylene sulfide (CF/PPS) and the like, are applied to the fields of aerospace, new energy automobiles, high-end equipment and the like due to high specific strength, high specific stiffness, excellent impact resistance, weldability and recyclability. The laser-assisted automatic laying technology rapidly and locally heats the prepreg tape at a laying point through a laser beam to melt the thermoplastic matrix, and then realizes interlayer welding and consolidation through pressurization of a compacting roller, so that the method has the advantages of no need of an autoclave, short manufacturing period and the like. However, the existing laser-assisted automatic laying technology is generally carried out in an open environment, and has the defects that firstly, a thermoplastic resin matrix (such as PEEK and PPS) is exposed to air at high temperature (often exceeding the melting temperature) generated by laser, oxidization, thermal degradation or molecular chain fracture are easy to occur, secondly, a single laser radiation heating mode is easy to influence heat transfer by factors such as surface reflection of a prepreg tape, convective heat dissipation of the environment and the like, particularly when a curved surface member is laid or processed at a high speed, the temperature of a laying point is difficult to stably maintain at an optimal melting window quickly and uniformly, thirdly, in the prior art, the method for inhibiting oxidization or adopting a method for purging inert gases (such as nitrogen, argon, carbon dioxide, helium and mixed gases thereof) to a processing area in a large range is adopted, the gas diffusion is fast, the consumption is large, the protective atmosphere is unstable, the operation cost is high, and the effective low-oxygen environment is difficult to form and maintain at the laying point which moves at a high speed. At present, in the field of automatic laying of thermoplastic composite materials, a method for preventing the thermoplastic materials from being oxidized, improving peak laser power and widening a process window by utilizing local inert gas protection is not disclosed and reported. Therefore, an in-situ forming process and apparatus capable of providing stable and efficient high-temperature inert gas protection for the laying points while laser heating and realizing heat composite input and zone temperature control are needed. Disclosure of Invention The invention aims to provide a laser-assisted in-situ forming process and device protected by high-temperature inert gas, which solve the problems in the prior art. In order to achieve the above purpose, the invention provides a laser-assisted in-situ forming process protected by high-temperature inert gas, comprising the following steps: S1, feeding and laying materials, namely feeding continuous fiber reinforced thermoplastic and dragging a prepreg tape to a laying point; S2, heating the prepreg tape in the laying point area by adopting laser in an auxiliary manner, so that the thermoplastic matrix reaches a molten or high-elastic state and meets the requirement of in-situ welding; s3, inert gas protection and composite heating, wherein an inert gas protection cover is arranged on the periphery of the laying point, the inert gas protection cover covers an area at least comprising a laser heating area and a compaction area, heated inert gas is supplied into the inert gas protection cover to form local inert atmosphere covering the laying point, and the inert gas forms composite heating with laser heating in the S2 through convection heat exchange; and S4, compacting and in-situ consolidation, namely compacting the compositely heated prepreg tape by a compacting roller under the coverage of the inert gas protection cover to realize in-situ consolidation. Preferably, in S3, the inert gas is nitrogen, argon, carbon dioxide, helium or a mixed gas thereof. Preferably, in S3, at least two independent temperature control partitions are disposed in the inert gas protection cover along the laying direction, and the temperature control of each partition is achieved by independently adjusting the temperature or flow rate of the inert gas led to each partition. Preferably, the temperature control zone comprises a melt compacting zone, and further comprises at least one of a preheating zone and a pre-cooling zone, wherein the temperature of the inert gas supplied to the melt compacting zone is controlled to be higher than ambient temperature and within a range of tm±