Laser forging printing method and system for improving high smoothness of inner surface of thin-wall special-shaped pipe

Abstract

The invention provides a laser forging printing method and system for improving the high smoothness of the inner surface of a thin-wall special-shaped pipe. The method comprises the steps that a laser forging printing instruction is received; the fiber laser and the femtosecond laser are triggered, the powder laid on the substrate is scanned according to the corresponding scanning paths from the same forging printing starting point and the same starting moment, and the size of laser emitted by the fiber laser is larger than that of laser emitted by the femtosecond laser; the path trends of the scanning paths corresponding to the fiber laser and the femtosecond laser are consistent; in the scanning processing process, an infrared thermal imager is triggered to generate temperature field data, so that the scanning path of the femtosecond laser is locally adjusted based on the temperature field data until the laser emitted by the optical fiber laser and the laser emitted by the femtosecond laser reach the forging printing end point; and the process is repeated, and the thin-wall special-shaped pipe is formed when preset conditions are met. The high smoothness of the inner surface of the thin-wall special-shaped pipe can be remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal additive manufacturing, in particular to a method and system for improving the high smoothness of the inner surface of a thin-walled special-shaped pipe. BACKGROUND

[0002] As the core material of key fluid components such as aircraft engine fuel nozzles and aerospace propellant delivery pipelines, the inner surface quality of nickel-based superalloy directly affects the erosion resistance and medium flow efficiency of the components. Although the traditional laser powder bed fusion (LPBF) technology can realize near-net forming of special-shaped pipes, there are still the following bottlenecks in the application of nickel-based alloys: uncontrollable adhesion of inner surface slag, cumulative effect of interlayer thermal stress, and degradation of post-processing heat affected zone. Current improvement schemes such as inner cavity abrasive flow polishing and chemical etching have limitations such as poor accessibility of complex pipelines and loss of dimensional accuracy. SUMMARY

[0003] Therefore, the purpose of the present application is to provide a method and system for improving the high smoothness of the inner surface of a thin-walled special-shaped pipe, which can significantly improve the high smoothness of the inner surface of a thin-walled special-shaped pipe.

[0004] In a first aspect, the present application provides a method for improving the high smoothness of the inner surface of a thin-walled special-shaped pipe, comprising: Step 1, receiving a laser forging printing instruction; Step 2, triggering a fiber laser and a femtosecond laser to scan the powder laid on the substrate according to their respective corresponding scan paths at the same forging printing starting point and the same starting time, the laser size emitted by the fiber laser is larger than the laser size emitted by the femtosecond laser, and the path trends of the respective corresponding scan paths of the fiber laser and the femtosecond laser are consistent; Step 3, during the scanning process, triggering an infrared thermal imager to generate temperature field data, and locally adjusting the scan path of the femtosecond laser based on the temperature field data until the laser emitted by the fiber laser and the laser emitted by the femtosecond laser both reach the forging printing endpoint; Step 4, returning to execute step 2, and forming a thin-walled special-shaped pipe when a predetermined condition is met.

[0005] In one embodiment, locally adjusting the scan path of the femtosecond laser based on the temperature field data comprises: Based on the temperature field data, generating a surface topography image for the molten region formed after scanning processing by the fiber laser; Extracting defect features contained in the surface topography image; Locally adjusting the scan path of the femtosecond laser using the defect features, and the scan path of the femtosecond laser adopts a spiral path.

[0006] In an embodiment, the scanning path of the femtosecond laser is locally adjusted by using the defect feature, comprising: determining the shortest distance between the defect feature and the scanning path of the femtosecond laser; in the case that the shortest distance is greater than a preset distance threshold, determining a local path to be adjusted in the scanning path of the femtosecond laser, and offsetting the local path to the defect feature side, so that the adjusted local path covers the defect feature; fusing and smoothing the adjusted local path with the scanning path of the femtosecond laser to obtain the adjusted scanning path of the femtosecond laser.

[0007] In an embodiment, after offsetting the local path to the defect feature side, the method further comprises: based on the temperature attribute of the defect feature, adjusting the laser parameter associated with the adjusted local path.

[0008] In an embodiment, based on the temperature attribute of the defect feature, adjusting the laser parameter associated with the adjusted local path, comprising: by a PID controller, based on the local temperature value and the temperature gradient of the defect feature, adjusting one or more of the pulse energy, the scanning speed, and the path spacing associated with the adjusted local path.

[0009] In a second aspect, the present application also provides a laser forging printing system for improving the high smoothness of the inner surface of a thin-walled special-shaped tube, comprising: an instruction receiving module for receiving a laser forging printing instruction; a forging module for triggering a fiber laser and a femtosecond laser to scan the powder laid on the substrate according to their respective scanning paths at the same forging printing starting point and the same starting time, the laser size emitted by the fiber laser being larger than the laser size emitted by the femtosecond laser, and the path trends of the respective scanning paths of the fiber laser and the femtosecond laser being consistent; an adjustment module for triggering an infrared thermal imager to generate temperature field data during the scanning process, and locally adjusting the scanning path of the femtosecond laser based on the temperature field data until the laser emitted by the fiber laser and the laser emitted by the femtosecond laser both reach the forging printing endpoint; a repeated execution module for returning to call the forging module and forming a thin-walled special-shaped tube when a preset condition is met.

[0010] In an embodiment, the adjustment module is specifically used for: based on the temperature field data, generating a surface topography image for the molten region formed after the scanning processing by the fiber laser; extracting the defect feature contained in the surface topography image; The scanning path of the femtosecond laser is locally adjusted by using the defect feature, and the scanning path of the femtosecond laser adopts a spiral path.

[0011] In an implementation, the adjusting module is specifically configured to: determine a shortest distance between the defect feature and the scanning path of the femtosecond laser; in a case where the shortest distance is greater than a preset distance threshold, determine a local path to be adjusted in the scanning path of the femtosecond laser, and offset the local path to the defect feature side, so that the adjusted local path covers the defect feature; fuse and smooth the adjusted local path with the scanning path of the femtosecond laser, to obtain an adjusted scanning path of the femtosecond laser.

[0012] In a third aspect, the present application further provides an electronic device, comprising a processor and a memory, the memory storing computer executable instructions capable of being executed by the processor, and the processor executes the computer executable instructions to implement the method of any one of the first aspect.

[0013] In a fourth aspect, the present application further provides a computer readable storage medium, the computer readable storage medium storing computer executable instructions, and the computer executable instructions, when called and executed by a processor, cause the processor to implement the method of any one of the first aspect.

[0014] The method and system for laser forging printing of the inner surface of a thin-walled special-shaped tube with high surface smoothness provided by the present application first receive a laser forging printing instruction, trigger a fiber laser and a femtosecond laser, and perform scanning processing on the powder laid on the substrate according to the respective corresponding scanning paths at the same forging printing starting point and the same starting time. The laser size emitted by the fiber laser is larger than the laser size emitted by the femtosecond laser, and the path trends of the respective corresponding scanning paths of the fiber laser and the femtosecond laser are consistent. During the scanning processing, an infrared thermal imager is triggered to generate temperature field data, and the scanning path of the femtosecond laser is locally adjusted based on the temperature field data until the laser emitted by the fiber laser and the laser emitted by the femtosecond laser both reach the forging printing endpoint. The process is repeated, and the thin-walled special-shaped tube is formed when the preset condition is met. The above method triggers the fiber laser and the femtosecond laser to emit light at the same time, controls the interlayer femtosecond laser, automatically locally adjusts the scanning path of the femtosecond laser, realizes the synchronous optimization of surface remelting shaping and stress release, breaks through the technical contradiction that the surface smoothness and the microstructure stability are difficult to be compatible in the traditional process, and significantly improves the inner surface high smoothness of the thin-walled special-shaped tube, i.e., reduces the roughness of the inner surface of the thin-walled special-shaped tube.

[0015] Other features and advantages of the present application will be set forth in the descriptions that follow, and in part will be apparent from the description, or can be learned by practice of the application. The purposes and other advantages of the present application will be realized and attained by the structures particularly pointed out in the description, claims and drawings.

[0016] In order to make the above objectives, features and advantages of the present application more apparent, the following will be described in detail with reference to the preferred embodiments and in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings described below are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0018] Figure 1 A flowchart of a laser forging printing method for improving the high surface finish of the inner surface of a thin-walled special-shaped pipe provided by the embodiment of the present application is shown in the figure. Figure 2 A system architecture diagram of a laser forging printing method for improving the high surface finish of the inner surface of a thin-walled special-shaped pipe provided by the embodiment of the present application is shown in the figure. Figure 3 A technical framework diagram of a laser forging printing method for improving the high surface finish of the inner surface of a thin-walled special-shaped pipe provided by the embodiment of the present application is shown in the figure. Figure 4 A structure diagram of a laser forging printing system for improving the high surface finish of the inner surface of a thin-walled special-shaped pipe provided by the embodiment of the present application is shown in the figure. Figure 5 A structure diagram of an electronic device provided by the embodiment of the present application is shown in the figure.

[0019] Icon: 1-fiber laser; 2-powder bed laser; 3-special-shaped pipe workpiece; 4-femtosecond laser; 5-femtosecond laser; 6-infrared thermal imager. DETAILED DESCRIPTION

[0020] In order to make the purposes, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the present application will be described in detail below in conjunction with the embodiments. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0021] Nickel-based superalloy is the core material of key fluid components such as aircraft engine fuel nozzle and space propulsion agent delivery pipeline. The inner surface quality directly affects the anti-erosion performance and medium flow efficiency of the components. Although the traditional laser powder bed fusion (LPBF) technology can realize the near-net forming of special-shaped pipes, there are still the following bottleneck problems in the application of nickel-based alloy: 1. Uncontrollable adhesion of inner surface slag: high surface tension (≥1.8 N / m) leads to intensified globularization effect at the edge of the molten pool, and a large number of unmelted globularized particles adhere to the inner wall of the lumen, the inner surface roughness Ra>6μm, far exceeding the service standard of Ra≤0.8μm of aviation hydraulic pipeline.

[0022] 2. Interlayer thermal stress accumulation effect: the anisotropy of heat dissipation of thin-walled structure induces residual stress gradient, X-ray diffraction measurement shows that the stress amplitude in the transition zone reaches ±400MPa, which leads to the deviation of the ellipticity of the special-shaped pipe >0.15mm, and the traditional mechanical polishing cannot handle the curved flow channel and will introduce plastic deformation.

[0023] 3. Degradation of heat-affected zone after post-processing: the existing electrolytic polishing (ECP) or laser remelting post-processing improves the roughness while causing the dissolution of γ' strengthening phase and the precipitation of grain boundary δ phase, resulting in a 15-20% decrease in high-temperature hardness at 800℃.

[0024] Current improvement schemes such as inner cavity abrasive flow polishing and chemical etching have limitations such as poor accessibility of complex pipes (efficiency attenuation of 90% when depth-width ratio >5:1), loss of dimensional accuracy (wall thickness reduction ≥8%).

[0025] Therefore, the present embodiment provides a laser forging printing method and system for improving the high smoothness of the inner surface of a thin-walled special-shaped pipe. Unlike existing separate post-processing processes, the present embodiment proposes interlayer femtosecond laser control, which applies 50-200kHz femtosecond laser scanning to the molten region formed after scanning processing by a fiber laser, realizes synchronous optimization of surface remelting shaping and stress release, breaks through the technical contradiction between surface smoothness and microstructure stability in traditional processes, and significantly improves the high smoothness of the inner surface of a thin-walled special-shaped pipe.

[0026] In order to facilitate the understanding of the present embodiment, first, a laser forging printing method for improving the high smoothness of the inner surface of a thin-walled special-shaped pipe is introduced in detail. This method is particularly suitable for precise forming of thin-walled special-shaped pipe components and can solve the technical problems of excessive roughness and residual stress concentration in complex pipe inner surfaces in laser powder bed fusion (LPBF) technology. Referring to the flowchart of a laser forging printing method for improving the high smoothness of the inner surface of a thin-walled special-shaped pipe shown in Figure 1 The method mainly includes the following steps 1 to 4: Step 1, receiving a laser forging printing instruction.

[0027] Step 2, trigger the fiber laser and the femtosecond laser to scan the powder laid on the substrate according to the respective corresponding scan paths at the same forging printing starting point and the same starting time.

[0028] In the formula, the laser size emitted by the fiber laser is larger than the laser size emitted by the femtosecond laser, the path trends of the respective corresponding scan paths of the fiber laser and the femtosecond laser are consistent, and the scan path of the fiber laser can adopt a spiral progressive path. In specific implementation, since the laser size emitted by the fiber laser is larger than the laser size emitted by the femtosecond laser, after the laser emitted by the fiber laser and the laser emitted by the femtosecond laser are simultaneously controlled, the molten area formed by the area scanned by the fiber laser, and the non-contact scanning of the femtosecond laser in the molten area can realize the effects of slag ablation, stress release, and organization stabilization.

[0029] Step 3, in the scanning process, trigger the infrared thermal imager to generate temperature field data, and locally adjust the scan path of the femtosecond laser based on the temperature field data until the laser emitted by the fiber laser and the laser emitted by the femtosecond laser reach the forging printing endpoint.

[0030] In an embodiment, the defects existing in the molten area and the characteristic information (referred to as defect characteristics) thereof can be identified according to the temperature field data, the local path in the scan path of the femtosecond laser is adjusted by using the defect characteristics, and the laser parameters (such as pulse energy, scanning speed, path spacing, etc.) bound by the local path are adjusted, so as to better improve the high smoothness of the inner surface of the thin-walled special-shaped pipe.

[0031] Step 4, return to execute step 2, and form the thin-walled special-shaped pipe when the preset condition is met.

[0032] The laser forging printing method for improving the high smoothness of the inner surface of the thin-walled special-shaped pipe provided by the embodiment of the present application triggers the fiber laser and the femtosecond laser to emit light at the same time, controls the femtosecond laser by the interlayer femtosecond laser, automatically adjusts the scan path of the femtosecond laser locally, realizes the synchronous optimization of surface remelting shaping and stress release, breaks through the technical contradiction that the surface smoothness and the microstructure stability are difficult to be compatible in the traditional process, and significantly improves the high smoothness of the inner surface of the thin-walled special-shaped pipe, that is, reduces the roughness of the inner surface of the thin-walled special-shaped pipe.

[0033] In view of the problems of uncontrollable adhesion of inner surface slag, accumulation of residual stress of thin-walled structure, and poor post-processing organization stability in the prior art, the embodiment of the present application provides a laser forging printing method for improving the high smoothness of the inner surface of the thin-walled special-shaped pipe, which realizes the reduction of the inner surface roughness (Ra) of the special-shaped pipe from > 6 μm to ≤ 0.8 μm.

[0034] Firstly, referring to Figure 2A system architecture diagram of a laser forging printing method for improving the inner surface high smoothness of a thin-walled special-shaped tube is shown, and the system architecture diagram comprises a fiber laser 1, a powder bed laser 2, a special-shaped tube workpiece 3, a femtosecond laser 4, a femtosecond laser 5 and an infrared thermal imager 6.

[0035] On this basis, the embodiment of the present application provides Figure 3 A technical framework diagram of a laser forging printing method for improving the inner surface high smoothness of a thin-walled special-shaped tube is shown, and the technical framework diagram comprises: powder pretreatment and substrate preparation; processing system integration and parameter setting; laser melting forming layer preparation and femtosecond laser interlayer regulation; online dynamic adjustment; cross-layer circulation and post-processing. The core of the method is to build a "melting-regulation-monitoring" closed-loop cooperative system. The embodiment of the present application takes an aviation engine nickel-based high-temperature alloy (IN738LC) fuel nozzle thin-walled special-shaped tube as an example to describe the implementation process of the laser forging printing method for improving the inner surface smoothness, and the specific implementation process is as follows: (I) Powder pretreatment and substrate preparation: IN738LC nickel-based high-temperature alloy powder (particle size distribution 15-53 μm, oxygen content ≤0.025wt%) is selected, a 15nm thick aluminum oxide (Al2O3) coating is deposited on the surface of the powder by magnetron sputtering, and the femtosecond laser absorption rate is increased to 88%.

[0036] The substrate is made of Hastelloy X, after sand blasting treatment (surface roughness Ra=3.2 μm), step-by-step ultrasonic cleaning with acetone and ethanol for 20 minutes is adopted to remove surface oil stains and particles.

[0037] (II) Processing system integration and parameter setting: Melting forming unit: IPG YLS-400 fiber laser (wavelength 1070nm, spot diameter 80 μm, power range 200-600W); Interlayer regulation unit: Spectra-Physics femtosecond laser (wavelength 1064nm, pulse width 350fs, spot diameter 70 μm, single pulse energy 0.5mJ, repetition frequency 120kHz); Online monitoring unit: FLIR A6750sc dual-wavelength infrared thermal imager (frame rate 1200fps, temperature measurement accuracy ±3℃); Control system: NI PXIe-8880 real-time controller (time resolution 0.1 μs), integrated temperature-stress coupling algorithm module.

[0038] (III) Laser melting forming layer preparation and femtosecond laser interlayer regulation: The embodiment of the present application simultaneously controls the fiber laser and the femtosecond laser to scan.

[0039] ​The process of controlling the fiber laser to scan is as follows: powder layer thickness: 40 μm; melting parameters: laser power 450 W, scanning speed 1000 mm / s, overlap rate 35%, molten pool depth controlled at 250 ± 10 μm; protective atmosphere: high-purity argon (oxygen content ≤0.01%), gas flow rate 12 L / min. In a specific embodiment, a 200-800 W fiber laser is used to scan the nickel-based superalloy powder layer by layer with a 70-90 μm spot diameter, the molten pool depth is controlled at 200-350 μm, and the layer thickness is set at 20-50 μm.

[0040] The process of controlling the femtosecond laser to scan is as follows: start the 1064 nm femtosecond laser system for non-contact surface scanning, perform spiral progressive scanning with a 0.1 mm offset along the inner wall profile of the tube, and the key parameters are: spot diameter: 50-100 μm; single pulse energy: 0.2-0.8 mJ; repetition rate: 100-150 kHz. In a specific embodiment, the single pulse energy is 0.4 mJ, the scanning speed is 2 m / s, and the line spacing is 60 μm.

[0041] In the process of controlling the femtosecond laser to scan, the following composite effects will be produced: spherical particle selective vaporization: ablation of adherent slag with a diameter ≤80 μm through multi-photon absorption effect, experimental verification of vaporization of adherent spherical particles with a diameter ≤50 μm through multi-photon absorption effect; micro-area stress release: induction of <1 μm depth non-thermal melting-re-solidification of the surface layer, elimination of 40-60% local stress, experimental verification of induction of 0.8 μm depth non-thermal melting-re-solidification of the surface layer, elimination of 55% local residual stress; γ' phase stability control: surface layer heating rate >10 7 K / s inhibits element diffusion, γ' phase size change rate <3%, experimental verification of controlling peak temperature ≤1000℃, γ' phase size change rate <2.5%.

[0042] (Four) Online dynamic adjustment: (4.1) Based on the temperature field data, a surface topography image is generated for the molten region formed after scanning by the fiber laser. In an example, the temperature field data can be input into a pre-trained neural network to generate a surface topography image corresponding to the molten region.

[0043] (4.2) Extract the defect features contained in the surface topography image. In an example, the edge information of the surface topography image can be extracted to determine the location of the concave position of the molten region; threshold segmentation algorithm can be used to segment the reflective spherical particles from the surface topography image, and morphological operation (such as circularity analysis) is used to screen particles with a diameter >5 μm, and the coordinates, number and distribution density of the particles are recorded to obtain the spherical particles of the molten region, etc.

[0044] (4.3) Adjusting the scanning path of the femtosecond laser locally by the defect feature, and the scanning path of the femtosecond laser adopts a spiral path. Specifically, the shortest distance between the defect feature and the scanning path of the femtosecond laser is determined, and in the case that the shortest distance is greater than a preset distance threshold, a local path to be adjusted in the scanning path of the femtosecond laser is determined, and the local path is offset to the defect feature side, so that the adjusted local path covers the defect feature. The adjusted local path and the scanning path of the femtosecond laser are fused and smoothed to obtain the adjusted scanning path of the femtosecond laser.

[0045] Specifically, for each defect point (or region center), the shortest distance d between it and all points on the current spiral path is calculated: if d ≤ a preset threshold (such as 30 μm, i.e. 1 / 2-1 / 3 of the laser spot radius), it is determined that the defect is within the effective range of the current path; if d > the threshold, it is determined that the defect is not covered by the current path, and the path needs to be adjusted. Along the radial direction of the defect, the local spiral path is offset to the defect side by Δr (Δr = d - threshold), to ensure that the defect is within the laser spot coverage range. For example: if the defect is located 35 μm outside the original path, the path is locally offset by 30 μm, so that the defect enters the center area of the laser spot.

[0046] Preferably, since the scanning progress of the fiber laser is faster than that of the femtosecond laser, the surface topography image can be updated at a preset time interval, and the region that has been scanned twice by the femtosecond laser is identified by combining the updated surface topography image and the current working position of the femtosecond laser. The image corresponding to the region is excluded from the updated surface topography image, and the foregoing (4.2) to (4.3) are repeated until the scanning of the layer is completed.

[0047] Further, after offsetting the local path to the defect feature side, the laser parameters associated with the adjusted local path can also be adjusted based on the temperature properties of the defect feature through a PID controller. In one embodiment, a dual-wavelength infrared temperature measuring instrument can be integrated to collect the temperature field of the regulation area in real time, and a temperature-stress coupling model constructed based on the PID principle is used to dynamically adjust the femtosecond laser energy, so as to ensure that the surface peak temperature ≤ γ' solubility critical value (nickel-based alloy about 1050℃); the heat affected zone depth < 5 μm. In specific implementation, the femtosecond laser parameters are adjusted through the PID controller: if the local temperature > 1050℃: automatically reduce the pulse energy to 0.3 mJ; if the temperature gradient > 200℃ / mm: reduce the scanning speed to 1.5 m / s and increase the line spacing to 80 μm. The target control is to ensure that the heat affected zone depth ≤ 4 μm, and the real-time estimated value of the surface roughness Ra ≤ 0.6 μm.

[0048] (Five) Cross-layer circulation and post-processing: Repeat (three) to (four) until the completion of all accumulation (total number of layers 1500 layers), finally execute: gradient cooling: from 650 DEG C to room temperature at a rate of 15 DEG C / min; stress release: annealing at 400 DEG C for 1 hour in a protective atmosphere, the residual stress is reduced to below ± 80 MPa.

[0049] Finally, the quality of the formed thin-walled special-shaped tube (wall thickness 0.8 mm, bending radius R = 5 mm) is detected.

[0050] In summary, the laser forging printing method for improving the high surface finish of the inner surface of the thin-walled special-shaped tube provided by the embodiment of the application introduces a femtosecond laser secondary regulation process in the conventional LPBF interlayer processing process: while forming a molten layer by laser, a non-contact scanning process is performed on the molten area by using a femtosecond laser beam, wherein the femtosecond laser spot diameter is 50-100 microns, the single pulse energy is 0-1 mJ, and the repetition frequency is 50-200 kHz. By accurately controlling the energy density and scanning path of the femtosecond laser, the surface protrusions are selectively remelted on a sub-micron scale to reduce the surface roughness, and the controlled phase change of the surface layer material is induced to release the thermal stress accumulated in the fusion process. The embodiment of the application significantly improves the surface quality and service reliability of the inner cavity of precision components such as aerospace fuel pipelines and biomedical implants.

[0051] On the basis of the foregoing embodiments, the embodiment of the application provides a laser forging printing system for improving the high surface finish of the inner surface of a thin-walled special-shaped tube, referring to a structural schematic diagram of a laser forging printing system for improving the high surface finish of the inner surface of a thin-walled special-shaped tube as shown in the figure. Figure 4 The device mainly includes the following parts: The instruction receiving module 402 is configured to receive a laser forging printing instruction. The forging module 404 is configured to trigger the fiber laser and the femtosecond laser to perform scanning processing on the powder laid on the substrate according to the respective corresponding scanning paths at the same forging printing starting point and the same starting time, the laser size emitted by the fiber laser is larger than the laser size emitted by the femtosecond laser, and the path trends of the respective corresponding scanning paths of the fiber laser and the femtosecond laser are consistent. The adjustment module 406 is configured to trigger the infrared thermal imager to generate temperature field data during the scanning processing, and locally adjust the scanning path of the femtosecond laser based on the temperature field data until the laser emitted by the fiber laser and the laser emitted by the femtosecond laser both reach the forging printing endpoint. The repeated execution module 408 returns to call the forging module 404, and forms a thin-walled special-shaped tube when a preset condition is met.

[0052] The laser forging printing system for improving the inner surface high smoothness of the thin-wall special-shaped pipe provided by the embodiment of the present application breaks through the technical contradiction in the traditional process that the surface smoothness and the microstructure stability are difficult to be compatible, significantly improves the inner surface high smoothness of the thin-wall special-shaped pipe, and reduces the roughness of the inner surface of the thin-wall special-shaped pipe.

[0053] In an embodiment, the adjusting module 404 is specifically configured to: generate a surface topography image for the molten region formed after the scanning processing by the fiber laser based on the temperature field data; extract defect features contained in the surface topography image; locally adjust the scanning path of the femtosecond laser by using the defect features, and the scanning path of the femtosecond laser adopts a spiral path.

[0054] In an embodiment, the adjusting module 404 is specifically configured to: determine the shortest distance between the defect features and the scanning path of the femtosecond laser; in the case that the shortest distance is greater than a preset distance threshold, determine a local path to be adjusted in the scanning path of the femtosecond laser, and offset the local path to the defect feature side, so that the adjusted local path covers the defect feature; fuse and smooth the adjusted local path with the scanning path of the femtosecond laser to obtain the adjusted scanning path of the femtosecond laser.

[0055] In an embodiment, the adjusting module 404 is specifically configured to: adjust the laser parameters associated with the adjusted local path based on the temperature attribute of the defect features.

[0056] In an embodiment, the adjusting module 404 is specifically configured to: adjust one or more of the pulse energy, the scanning speed, and the path spacing associated with the adjusted local path by a PID controller based on the local temperature value and the temperature gradient of the defect features.

[0057] The device provided by the embodiment of the present application has the same implementation principle and technical effects as the foregoing method embodiment, and for brevity of description, the part not mentioned in the device embodiment can be referred to the corresponding content in the foregoing method embodiment.

[0058] The electronic device provided by the embodiment of the present application, specifically, comprises a processor and a storage device; the storage device stores a computer program, and the computer program performs the method according to any one of the above embodiments when being run by the processor.

[0059] Figure 5 The structural schematic diagram of the electronic device provided by the embodiment of the present application, the electronic device 100 comprises a processor 50, a memory 51, a bus 52 and a communication interface 53, the processor 50, the communication interface 53 and the memory 51 are connected through the bus 52; the processor 50 is used for executing the executable module stored in the memory 51, for example, a computer program.

[0060] The memory 51 can contain a high-speed random access memory (RAM), and can also include a non-volatile memory, for example, at least one disk memory. The communication connection between the system network element and at least one other network element is realized through at least one communication interface 53 (which can be wired or wireless), and the Internet, a wide area network, a local area network, a metropolitan area network, etc. can be used.

[0061] The bus 52 can be an ISA bus, a PCI bus or an EISA bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For the convenience of representation, Figure 5 Only one bidirectional arrow is used in the figure, but it does not mean that there is only one bus or one type of bus.

[0062] The memory 51 is used for storing a program, and the processor 50 executes the program after receiving an execution instruction. The method performed by the device defined by the flow process disclosed in any one of the above embodiments can be applied to the processor 50 or realized by the processor 50.

[0063] The processor 50 can be an integrated circuit chip with signal processing capability. In implementation, each step of the above method can be completed by integrated logic circuit of hardware in the processor 50 or by instructions in the form of software. The processor 50 described above can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component. Each method, step and logic block diagram disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor. The steps of the method disclosed in combination with the embodiments of the present application can be directly embodied as a hardware code processor for execution, or a combination of hardware and software modules in the code processor for execution. The software module can be located in a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium in the art. The storage medium is located in the memory 51, and the processor 50 reads the information in the memory 51, and combines the hardware to complete the steps of the above method.

[0064] The computer program product of the readable storage medium provided by the embodiments of the present application includes a computer readable storage medium storing program codes, and the program codes include instructions for executing the method described in the foregoing method embodiments. For specific implementation, reference can be made to the foregoing method embodiments, which will not be described here.

[0065] If the functions are realized in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the parts of the present application that essentially contribute to the prior art or the parts of the technical solutions can be embodied in the form of software products. The computer software product is stored in a storage medium and includes instructions for making a computer device (which can be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the method described in the embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0066] Finally, it should be noted that: the above-described embodiments are only specific embodiments of the present application, which are used to illustrate the technical solutions of the present application, but not to limit them. The protection scope of the present application is not limited to this. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily think of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed by the present application, or make equivalent replacements to some of the technical features. The modifications, changes or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A laser forging printing method for improving the high surface finish of the inner surface of thin-walled irregularly shaped tubes, characterized in that, include: Step 1: Receive laser forging printing instructions; Step 2: Trigger the fiber laser and the femtosecond laser to scan the powder on the substrate at the same forging printing starting point and the same starting time, according to their respective scanning paths. The laser size emitted by the fiber laser is larger than that emitted by the femtosecond laser, and the path trends of the scanning paths corresponding to the fiber laser and the femtosecond laser are consistent. Step 3: During the scanning process, the infrared thermal imager is triggered to generate temperature field data, and the scanning path of the femtosecond laser is locally adjusted based on the temperature field data until the laser emitted by the fiber laser and the laser emitted by the femtosecond laser both reach the forging printing endpoint. Step 4: Return to step 2 and form a thin-walled irregular tube when the preset conditions are met.

2. The laser forging printing method for improving the high surface finish of the inner surface of thin-walled irregular tubes according to claim 1, characterized in that, Locally adjusting the scanning path of the femtosecond laser based on the temperature field data includes: Based on the temperature field data, a surface morphology image is generated for the molten region formed after scanning and processing by the fiber laser; Extract the defect features contained in the surface topography image; The scanning path of the femtosecond laser is locally adjusted using the aforementioned defect characteristics, and the scanning path of the femtosecond laser adopts a spiral path.

3. The laser forging printing method for improving the high surface finish of the inner surface of thin-walled irregular tubes according to claim 2, characterized in that, Local adjustment of the scanning path of the femtosecond laser using the aforementioned defect features includes: Determine the shortest distance between the defect feature and the scanning path of the femtosecond laser; If the shortest distance is greater than a preset distance threshold, a local path to be adjusted in the scanning path of the femtosecond laser is determined, and the local path is shifted toward the defect feature side so that the adjusted local path covers the defect feature; The adjusted local path is fused and smoothed with the scanning path of the femtosecond laser to obtain the adjusted scanning path of the femtosecond laser.

4. The laser forging printing method for improving the high surface finish of the inner surface of thin-walled irregular tubes according to claim 3, characterized in that, After offsetting the local path toward the defect feature side, the method further includes: Based on the temperature properties of the defect characteristics, the laser parameters associated with the adjusted local path are adjusted.

5. The laser forging printing method for improving the high surface finish of the inner surface of thin-walled irregular tubes according to claim 4, characterized in that, Based on the temperature properties of the defect characteristics, the laser parameters associated with the adjusted local path are adjusted, including: Using a PID controller, based on the local temperature value and temperature gradient of the defect characteristics, one or more of the pulse energy, scan speed, and path spacing associated with the adjusted local path are adjusted.

6. A laser forging printing system for improving the high surface finish of the inner surface of thin-walled irregularly shaped tubes, characterized in that, include: The instruction receiving module is used to receive laser forging printing instructions; The forging module is used to trigger the fiber laser and the femtosecond laser to scan the powder on the substrate according to their respective scanning paths, starting from the same forging printing start point and the same start time. The laser size emitted by the fiber laser is larger than that emitted by the femtosecond laser, and the path trends of the scanning paths corresponding to the fiber laser and the femtosecond laser are consistent. An adjustment module is used to trigger an infrared thermal imager to generate temperature field data during the scanning process, so as to locally adjust the scanning path of the femtosecond laser based on the temperature field data until both the laser emitted by the fiber laser and the laser emitted by the femtosecond laser reach the forging printing endpoint. The repeated execution module returns to call the forging module, and a thin-walled irregular tube is formed when the preset conditions are met.

7. The laser forging printing system for improving the high surface finish of the inner surface of thin-walled irregularly shaped tubes according to claim 6, characterized in that, The adjustment module is specifically used for: Based on the temperature field data, a surface morphology image is generated for the molten region formed after scanning and processing by the fiber laser; Extract the defect features contained in the surface topography image; The scanning path of the femtosecond laser is locally adjusted using the aforementioned defect characteristics, and the scanning path of the femtosecond laser adopts a spiral path.

8. The laser forging printing system for improving the high surface finish of the inner surface of thin-walled irregular tubes according to claim 7, characterized in that, The adjustment module is specifically used for: Determine the shortest distance between the defect feature and the scanning path of the femtosecond laser; If the shortest distance is greater than a preset distance threshold, a local path to be adjusted in the scanning path of the femtosecond laser is determined, and the local path is shifted toward the defect feature side so that the adjusted local path covers the defect feature; The adjusted local path is fused and smoothed with the scanning path of the femtosecond laser to obtain the adjusted scanning path of the femtosecond laser.

9. An electronic device, characterized in that, The method includes a processor and a memory, the memory storing computer-executable instructions executable by the processor, the processor executing the computer-executable instructions to implement the method of any one of claims 1 to 5.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions that, when invoked and executed by a processor, cause the processor to perform the method described in any one of claims 1 to 5.

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