Full-laser additive and subtractive composite manufacturing method and full-laser additive and subtractive composite manufacturing device

Abstract

The invention relates to the technical field of additive and subtractive manufacturing, in particular to a full-laser additive and subtractive composite manufacturing method and a full-laser additive and subtractive composite manufacturing device, and according to the method, a current layer is machined by switching pulse laser and continuous laser, and additive and subtractive treatment is conducted on the current layer. According to the additive and subtractive treatment, the distribution of an interface morphology material and an internal structure of a current layer can be changed, and a formed interface layer can regulate and control the flowing state and the internal stress of a molten pool in the subsequent additive process, so that the effects of inducing and refining structure growth are achieved; according to the method, forming of a more precise fine structure can be achieved through cooperation of layer-by-layer material increasing and material decreasing, continuous laser and pulse laser are compositely utilized in the method, the manufacturing precision, the surface quality and the internal quality of an additive manufacturing part can be effectively improved, and the part has the advantage of being good in mechanical property. The device comprises an optical system, the optical system comprises a pulse laser module and a continuous laser module, and the pulse laser module and the continuous laser module are arranged to operate independently or simultaneously.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to a full laser additive and subtractive composite manufacturing method and a full laser additive and subtractive composite manufacturing device. Background Art

[0002] Additive manufacturing technology can directly manufacture parts of complex shapes by melting or solidifying them layer by layer. It has the advantages of high forming freedom and suitability for personalized customization. It is widely used in aerospace, medical equipment, molds, energy and other fields, and has become one of the advanced manufacturing technologies that countries are competing to develop. However, the current additive manufacturing equipment has a relatively single function and uses one or more identical light sources for forming and manufacturing, which has always faced problems such as poor forming effect and low forming efficiency.

[0003] In order to solve the above problems, a method of using continuous and pulsed lasers for additive manufacturing has emerged in recent years. The patent CN117182120A "A high surface quality laser additive manufacturing device and method" uses continuous and pulsed lasers to perform surface processing to improve surface quality. However, this method only partially solves the surface quality problem by performing surface processing, and cannot use continuous lasers and pulsed lasers to solve the internal material problems of parts.

[0004] CN114799229A "A powder-spreading multi-laser additive and subtractive composite precision manufacturing device and its processing method" introduces a method based on powder-spreading multi-laser additive and subtractive manufacturing and online detection. This method is limited to powder-spreading additive manufacturing and a combination of a continuous laser and a pulsed laser. It can only solve some surface quality and surface processing problems. It is difficult to adapt to various surfaces with greatly varying roughness in additive manufacturing, and it is difficult to solve problems such as difficult to control internal defects, large residual stress, and difficulty in achieving microstructure processing.

[0005] Therefore, the current composite continuous laser and pulsed laser processing methods still cannot effectively solve the problem of internal material quality in the additive manufacturing process. Summary of the invention

[0006] One of the purposes of the present invention is to avoid the shortcomings of the prior art and provide a full laser additive and subtractive composite manufacturing method, which utilizes continuous laser and pulsed laser in combination, can effectively improve the surface quality and internal quality of additively manufactured parts, so that the parts have the advantage of good mechanical properties.

[0007] A second object of the present invention is to provide a full laser additive and subtractive composite manufacturing device.

[0008] To achieve one of the above purposes, the present invention provides the following technical solutions:

[0009] A full laser additive and subtractive composite manufacturing method is provided. After the current layer is produced, the current layer is continued to be processed by switching between pulse laser and continuous laser, so that the current layer is subjected to additive and subtractive processing, wherein the pulse laser energy and the continuous laser energy are regulated to change the interface morphology of the current layer material, so that the surface of the current layer is vaporized, ablated or melted into an interface layer, and the surface morphology and internal tissue structure of the current layer are changed. The interface layer regulates the flow state of the molten pool in the subsequent additive process, induces and refines tissue growth, and then processes layer by layer until the target part is obtained.

[0010] In some embodiments, the pulsed laser energy is regulated to ablate the current layer so that the current layer forms a micro-nano structure, and the next forming layer is formed on the micro-nano structure of the current layer.

[0011] Or the pulse laser energy is regulated to ablate the surface of the part so that the surface of the part has a functional structure.

[0012] In some embodiments, the pulse laser energy is regulated to ablate the current layer so that the pulse laser generates shock waves and compressive stress in the current layer, and the shock waves and compressive stress change the grain size and morphology of the current layer, and dislocations are formed inside the current layer.

[0013] In some embodiments, continuous laser energy and / or pulsed laser energy is regulated to heat the current layer of material once or multiple times, and the temperature field distribution and change rate of the material are regulated to reduce the residual stress inside the material by heat treatment.

[0014] In some embodiments, the formation of more precise microstructures (micropores, thin walls, microchannels, microstructures) is achieved through the coordination of layer-by-layer additive and subtractive processes.

[0015] In some embodiments, a pulsed laser is used to perform laser polishing on the surface of a part and remove peripheral burrs.

[0016] In some embodiments, a pulse laser of a certain width is selected to remove powder adhering to the surface of the current layer by processing the surface of the current layer with the pulse laser.

[0017] In some embodiments, the cooling process of the molten pool induces growth and refinement of the material structure by machining an interface texture at the interface layer.

[0018] In some embodiments, the interfacial morphology of the material is formed by laser induction or processing.

[0019] In some embodiments, the hydrophilicity and hydrophobicity of the interface surface of the material are regulated by adjusting the laser parameters.

[0020] In some embodiments, the parameters of the pulse laser are: laser wavelength 200nm~20000nm, single pulse energy 1μJ~20mJ, repetition frequency 10kHz~3000kHz, pulse width 0.1fs~1s, spot size 10μm~100μm, and number of pulse spots 1~10.

[0021] In some embodiments, the parameters of the continuous laser are: laser wavelength 200nm to 20000nm, laser power 50W to 5000W, and spot size 0.05mm to 10mm.

[0022] In some embodiments, the laser spot shape includes one of square, elliptical, circular, ring, triangle, spindle, line, arc, petal, or a combination of any two or more thereof.

[0023] In some embodiments, the pulse laser performs milling, turning, and drilling on the current layer to form channels in the current layer, thereby achieving complex and fine hole formation.

[0024] In some embodiments, the material of the current layer is one or any combination of powder material, filament material, block material, and liquid material.

[0025] In some embodiments, the material is a composite material of one or any combination of organic matter, ceramic, elemental metal or alloy.

[0026] In some embodiments, the elemental metal comprises pure copper,

[0027] The alloy includes one or a combination of any two or more of stainless steel, titanium alloy, high temperature alloy, die steel, and Hastelloy.

[0028] In some embodiments, the formed interface layer regulates the flow state of the molten pool in the subsequent additive process to achieve the effect of inducing and refining the growth of the molten pool structure.

[0029] Beneficial effects of the all-laser additive and subtractive composite manufacturing method of the present invention:

[0030] The all-laser additive and subtractive composite manufacturing method of the present invention can perform all-laser additive and subtractive composite processing by switching between pulsed laser and continuous laser processing on the prepared current layer, and improve the interface state of the prepared current layer by effectively regulating the pulsed laser energy and continuous laser energy, so that the surface of the current layer is vaporized, ablated or melted, so that the interface of the current layer has texture characteristics, which is convenient for better connection with the lower forming layer, and changes the surface morphology and internal organization structure of the current layer. At the same time, the laser interface can regulate the flow state of the molten pool in the subsequent additive processing process, thereby playing the role of inducing and refining the growth of the organization, and finally improving the mechanical properties, strength and hardness of the entire part, overcoming the problem of poor product performance caused by traditional laser processing of the part surface only. In addition, by switching between pulsed laser and continuous laser processing of the current layer, the molding, heat treatment and polishing effects of more precise microstructures (micropores, thin walls, microchannels, microstructures) can be achieved.

[0031] To achieve the second objective above, the present invention provides the following technical solutions:

[0032] A full laser additive and subtractive composite manufacturing device is provided, the device is applied to the above-mentioned full laser additive and subtractive composite manufacturing method, and the device comprises:

[0033] An optical system comprises a pulse laser module and a continuous laser module, wherein the pulse laser module and the continuous laser module are configured to operate separately or simultaneously.

[0034] In some embodiments, an online monitoring closed-loop manufacturing parameter control module is further included, and the pulse laser module and the continuous laser module are respectively connected to the online monitoring closed-loop manufacturing parameter control module.

[0035] In some embodiments, a galvanometer is further included, and the galvanometer is respectively connected to the pulse laser module optical path and the continuous laser module optical path.

[0036] In some embodiments, a processing head is further included, wherein the processing head is provided with an optical path outlet, and the optical path outlet conducts the pulse laser module optical path and the continuous laser module optical path.

[0037] In some embodiments, a coaxial feeding structure is provided in the processing head, and the coaxial feeding structure is used to transport processing materials. The feeding direction of the coaxial feeding structure is the same as the processing direction of the processing head.

[0038] In some embodiments, the coaxial feeding structure is a coaxial powder feeding structure or a coaxial wire feeding structure.

[0039] In some embodiments, the processing head is a multi-degree-of-freedom processing head.

[0040] In some embodiments, it also includes a molding cylinder and a powder spreading mechanism, a multi-axis guide rail is arranged above the molding cylinder, the processing head is connected to the multi-axis guide rail, and the multi-axis guide rail controls the processing angle of the processing head.

[0041] In some embodiments, a processing table is further included, wherein the processing table is a multi-station processing table, and each station is used to process a part;

[0042] Or the processing table is a mobile processing table, and the mobile processing table drives the parts to move and be processed by each laser;

[0043] Or the processing table is a co-position processing table, and the co-position processing table processes multiple parts in parallel.

[0044] The invention provides a full laser additive and subtractive composite manufacturing device with the following beneficial effects:

[0045] The all-laser additive and subtractive composite manufacturing device of the present invention can be manufactured by a material spreading method or a direct energy deposition method to obtain the current layer. The added optical system is provided with multiple laser units, each laser unit includes a continuous laser module and a pulse laser module. The continuous laser modules and pulse laser modules corresponding to the processing head and the galvanometer respectively can act simultaneously or individually, so that different lasers can be used for processing at the same time in additive manufacturing. The joint action of multiple lasers can effectively improve the processing effect and improve the quality of additive manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a structural schematic diagram of a full laser additive and subtractive composite manufacturing device according to a specific embodiment of the present invention.

[0047] Figure 2 It is a diagram of processing effects obtained by various laser processing methods according to the specific implementation modes of the present invention.

[0048] Figure 3 It is a schematic diagram of the hardness change of the current layer material.

[0049] Figure 4 It is a schematic diagram of stress change in the current layer.

[0050] Figure 5 It is a production process diagram comparing the traditional method and the present invention.

[0051] Reference numerals:

[0052] 1. Optical system; 2. Galvanometer; 3. Pulse laser; 4. Processing head; 5. Multi-axis guide; 6. Continuous laser; 7. Forming cylinder; 8. Lifting platform; 9. Flipping mechanism; 10. Rotating platform; 11. Driving device; 12. Parts; 13. Powder spreading mechanism; 14. Computer. DETAILED DESCRIPTION

[0053] The preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0054] The current hybrid continuous laser and pulsed laser processing methods still cannot effectively solve the problem of internal material quality in the additive manufacturing process.

[0055] In view of the above problems, the following embodiments propose a manufacturing method using a combination of multiple continuous and multiple pulsed lasers and a full laser additive and subtractive composite manufacturing device to perform additive forming, contour processing, organization strengthening, heat treatment modulation, internal stress regulation, interface texturing and final surface functionalization on the material. It can achieve high surface quality forming, high internal quality forming, on-demand distribution of microstructure, on-demand distribution of residual stress, and improve the mechanical properties of additive and subtractive parts and the performance of functional parts.

[0056] The following specific implementation methods are all powder-laying additive manufacturing. The process of powder-laying additive manufacturing will not be described here in detail. Those skilled in the art are familiar with the specific operations based on powder-laying additive manufacturing. The following embodiments are carried out on the basis of powder-laying additive manufacturing.

[0057] Example 1

[0058] This embodiment discloses a full laser additive and subtractive composite manufacturing method, such as Figure 1-2 As shown, after the current layer is made, the current layer is made by additive manufacturing technologies including but not limited to powder bed fusion, direct deposition, photo-stereolithography, and acoustic manufacturing.

[0059] The current layer is processed continuously by switching between pulse laser 3 and continuous laser 6, so that the current layer is subjected to additive and subtractive processing, wherein the energy of pulse laser 3 and continuous laser 6 is regulated to change the interface morphology of the current layer material, so that the surface of the current layer is vaporized, ablated or melted, and the internal organizational structure of the surface morphology of the current layer is changed, and the flow state of the molten pool in the subsequent additive processing is regulated, thereby achieving the effect of inducing and refining organizational growth, and processing layer by layer until the target part 12 is obtained.

[0060] Specifically, the current layer is processed by switching between pulse laser 3 and continuous laser 6. For example, pulse laser 3 and continuous laser 6 can be used independently or simultaneously. Moreover, the interface morphology of the current layer and the internal tissue distribution of the material can be improved by adjusting the energy of pulse laser 3 and continuous laser 6. The layer is prepared layer by layer, and the corresponding processing layer can be selected according to actual needs for processing until the target part 12 is obtained, thereby effectively improving the internal quality of the entire part 12 and avoiding the poor forming quality caused by the inability of single laser forming to process the surface of the part 12.

[0061] In this embodiment, the energy of the pulse laser 3 is regulated to ablate the current layer, with a single pulse energy of 0.6 μJ to 10 mJ, a repetition frequency of 10 kHz to 3000 kHz, a pulse width of 0.1 fs to 10 ps, ​​and a spot size of 10 μm to 100 μm, so that the current layer forms a micro-nano structure, and the next forming layer is formed on the micro-nano structure of the current layer.

[0062] When the pulsed laser 3 energy ablates the current layer, an instantaneous high-temperature area is formed, and the high-temperature area removes the edge material. By adjusting the laser energy, the edge is smoothed or formed into a surface morphology including but not limited to corrugated, serrated, columnar, etc., so that the upper or side surface of the part 12 is formed with but not limited to super-hydrophilic, super-hydrophobic or grating structures, or the pulsed laser 3 energy is adjusted to ablate the surface of the part 12, so that the surface of the part 12 has a functional structure. Pulsed laser 3 processes micro-nano structures on the surface to improve the molten pool stability, morphology and forming quality of the next forming layer material. The micro-nano structures provide different surface wettability, so that the next processing layer can be better connected to the micro-nano structures.

[0063] In this embodiment, the energy of the pulse laser 3 is regulated to ablate the current layer, with a single pulse energy of 0.8μJ~10mJ, a repetition frequency of 10kHz~3000kHz, a pulse width of 0.1fs~5ps, and a spot size of 10μm~100μm, so that the pulse laser 3 generates shock waves and compressive stress in the current layer. The shock waves and the compressive stress change the grain size and morphology of the current layer, form dislocations inside the current layer, and improve the strength and hardness of the current layer or change the residual stress of the current layer.

[0064] Specifically, the energy of the pulse laser 3 is regulated according to actual needs to achieve pulse laser 3 ablation of the current layer, so the energy of the pulse laser 3 can be used to generate shock waves and compressive stress to change the crystal size and morphology of the current layer and achieve a strengthening effect.

[0065] In this embodiment, the energy of the continuous laser 6 and / or the energy of the pulsed laser 3 is regulated to heat the current layer of material once or multiple times, with a single pulse energy of 10μJ~100mJ, a repetition frequency of 10kHz~3000kHz, a pulse width of 10ps~100ns, and a spot size of 100μm~10mm, so that the temperature change rate and temperature gradient of the material temperature field can be accurately controlled by the laser energy, and the temperature field distribution and change rate reduce the residual stress inside the material below the current layer.

[0066] Specifically, the heat generated by the energy of the continuous laser 6 and / or the energy of the pulsed laser 3 heats the current layer of material, thereby overcoming the residual stress inside the current material and improving the quality of the material inside.

[0067] On the surface of the texture (texture is a microstructure), powder is evenly spread, and the energy of the continuous laser 6 and / or the pulsed laser 3 is adjusted to heat the current layer of material once or multiple times, with a single pulse energy of 10μJ to 100mJ, a repetition frequency of 10kHz to 3000kHz, a pulse width of 10ps to 100ns, and a spot size of 100μm to 10mm, so that the temperature change rate and temperature gradient of the material temperature field can be accurately controlled by the laser energy. The texture can regulate the flow of the molten pool on its surface.

[0068] Specifically, the heat generated by the continuous laser 6 energy and / or the pulsed laser 3 energy is used to heat the current layer of material, and during the cooling process of the molten pool, the material structure is induced to grow and refine on the texture surface.

[0069] In this embodiment, the surface of the part 12 is laser polished using a pulsed laser 3 .

[0070] Specifically, the mechanical properties of the surface of the part 12 are improved through the polishing effect of the pulse laser 3 .

[0071] In this embodiment, a pulse laser 3 with a certain width is selected to process the surface of the current layer by the pulse laser 3 to remove powder adhering to the surface of the current layer.

[0072] This removes the adhering powder in the current layer and improves the mechanical properties.

[0073] In this embodiment, the pulse laser 3 with a certain width is a nanosecond laser, which has a higher removal efficiency.

[0074] In this embodiment, the parameters of the pulse laser 3 are: laser wavelength 200nm~20000nm, single pulse energy 1μJ~20mJ, repetition frequency 10kHz~3000kHz, pulse width 0.1fs~1s, spot size 10μm~100μm, and number of pulse spots 1~10.

[0075] In this embodiment, the parameters of the continuous laser 6 are: laser wavelength 200nm-20000nm, laser power 50W-5000W, and spot size 0.05mm-10mm.

[0076] In this embodiment, the shape of the laser spot includes one of square, ellipse, circle, ring, triangle, spindle, line, arc, petal, or a combination of any two or more thereof.

[0077] Laser spots of different shapes can produce microstructures of different structural shapes.

[0078] In this embodiment, the pulse laser 3 performs milling, turning, and drilling on the current layer to form channels in the current layer, thereby realizing complex and fine hole forming, and overcoming the problem that the flow channels cannot be prepared inside the printed product in the traditional way.

[0079] In this embodiment, the material of the current layer is one of powder material, filament material, block material, liquid material or any combination thereof.

[0080] In this embodiment, the material is a composite material of one or any combination of organic matter, ceramic, elemental metal or alloy.

[0081] In this embodiment, the elemental metal includes pure copper.

[0082] The alloy includes one or a combination of any two or more of stainless steel, titanium alloy, high temperature alloy, die steel, and Hastelloy.

[0083] The specific material can be selected according to actual conditions.

[0084] The method can be applied to material spreading additive manufacturing or direct energy deposition additive manufacturing or photocuring additive manufacturing or acoustic curing additive manufacturing or a combination of the four, and can act on additive manufacturing of metals or ceramics or resins or biomaterials or a combination of the above materials. When forming the current layer, during the forming process of the current layer or after forming, the pulsed laser 3 is applied to the entire or partial area of ​​the current layer for subsequent interlayer processing. The continuous or pulsed laser 3 can process the interlayer interface to form a surface structure, and the surface structure changes the powder flow, light absorption and molten pool stability, effectively improves the powder uniformity, light absorption rate and forming stability, reduces defects and achieves high-precision forming; one or more pulses The pulse or continuous laser 6 acts on the interlayer interface at the same time. The pulse laser 3 forms shock waves and compressive stresses in the process of ablating the material. The shock waves and compressive stresses break the columnar crystals in the solidified area, realize fine grain strengthening and form dislocations inside the current layer, realize fine grain strengthening to improve the strength and hardness of the material, and effectively improve the internal quality of the current layer; and in the process of manufacturing the current layer, the selected area of ​​the current layer is heated by the continuous laser 6 and / or the pulse laser 3, which can effectively slow down the cooling process of the current layer material or heat the current layer material to near the annealing temperature, reduce the residual stress of the material, realize the control of the residual force distribution, and further improve the internal quality of the current layer. The pulse laser 3 can perform laser drilling or fine structure processing after the current layer is completed, and directly form an internal structure with excellent surface quality and shape accuracy after forming, realizing direct manufacturing of fine internal structures.

[0085] The all-laser additive and subtractive composite manufacturing device disclosed in this embodiment is characterized in that the device is the all-laser additive and subtractive composite manufacturing method mentioned above, and the device includes:

[0086] An optical system 1 includes a pulse laser 3 module and a continuous laser 6 module, wherein the pulse laser 3 module and the continuous laser 6 module are configured to operate separately or simultaneously.

[0087] The system realizes switching between pulse laser 3 modules and continuous laser 6 modules, which can be operated separately or together.

[0088] In this embodiment, an online monitoring closed-loop manufacturing parameter control module is also included, and the pulse laser 3 module and the continuous laser 6 module are respectively connected to the online monitoring closed-loop manufacturing parameter control module.

[0089] The working status of the pulse laser 3 module and the continuous laser 6 module are monitored in real time through the online monitoring closed-loop manufacturing parameter control module.

[0090] In this embodiment, a galvanometer 2 is also included, and the galvanometer 2 is respectively connected to the optical path of the pulse laser 3 module and the optical path of the continuous laser 6 module.

[0091] In this embodiment, a processing head 4 is further included. The processing head 4 is provided with an optical path outlet, and the optical path outlet conducts the pulse laser 3 module optical path and the continuous laser 6 module optical path.

[0092] An optical path outlet is arranged at the processing head 4 , and the optical path is driven while the processing head 4 is driven to process the current layer processed by the processing head 4 .

[0093] In this embodiment, the processing head 4 is provided with a coaxial feeding structure, which is used to feed the processing material, and the feeding direction of the coaxial feeding structure is the same as the processing direction of the processing head 4. This allows the processing head 4 to process while feeding the material, that is, the material can be fed and processed quickly.

[0094] In this embodiment, the coaxial feeding structure is a coaxial powder feeding structure or a coaxial wire feeding structure. The coaxial feeding structure can feed powder or wire, which is selected according to actual conditions.

[0095] In this embodiment, the processing head 4 is a multi-degree-of-freedom processing head 4. The processing head 4 can be operated with multiple degrees of freedom by adjusting the processing head 4. Exemplarily, the processing head 4 has more than 5 degrees of freedom, and forms or processes the top surface, side surface and bottom surface of the workpiece.

[0096] In this embodiment, it also includes a forming cylinder 7 and a powder spreading mechanism 13 . A multi-axis guide rail 5 is arranged above the forming cylinder 7 . The processing head 4 is connected to the multi-axis guide rail 5 . The multi-axis guide rail 5 controls the processing angle of the processing head 4 .

[0097] The machining head 4 is controlled by the multi-axis guide 5 so that the machining head 4 can perform multi-degree-of-freedom machining.

[0098] In this embodiment, a processing table is also included. The processing table is a multi-station processing table, and each station is used to process a part 12, so that one processing table can process multiple parts 12 at the same time.

[0099] Or the processing table is a mobile processing table, and the mobile processing table drives the part 12 to move and be processed by each laser, thereby realizing flow-type laser processing of the part 12 on the mobile processing table.

[0100] Or the processing table is a co-position processing table, and the co-position processing table processes multiple parts 12 in parallel. By placing multiple co-position processing tables in parallel, multiple parts 12 can be processed in parallel.

[0101] Example 2

[0102] The full laser additive and subtractive composite manufacturing method disclosed in this embodiment, when performing additive manufacturing of the current layer, includes the following steps:

[0103] When the edge of the current layer is formed, one or more pulsed lasers are applied to the central solidification area of ​​the current layer. The pulsed laser forms a shock wave in the solidification area. The shock wave propagates along the edge of the structure to form compressive stress. The shock wave breaks the columnar crystals, achieves fine grain strengthening, and improves the strength and hardness of the current layer. The compressive stress exists on the surface of the part. When cracks appear, the cracks are closed to prevent crack expansion and improve fatigue performance.

[0104] Exemplarily, during the forming process, a pulsed laser is used to act on the edge of the molten pool (melting area) within a range of 50-200 microns. After forming a layer, the edge area or the area that needs to be strengthened can be scanned to form shock wave strengthening and compressive stress. The shock wave breaks the columnar crystals to achieve fine grain strengthening and improve the strength and hardness of the material.

[0105] Furthermore, the microstructure and residual stress requirements required at different locations are determined, the manufacturing and strengthening processes of various parts are determined according to the database, the manufacturing process parameters and path parameters are obtained, and the parts are laser impact strengthened using a 50W to 500W pulsed laser. Specifically, areas with higher wear resistance or hardness of the parts require smaller grains, or form phases with higher hardness. Larger grains need to be formed in areas with higher toughness requirements. Residual compressive stress needs to be formed on the shallow surface of the part to inhibit crack propagation and improve fatigue performance.

[0106] To further illustrate the effect of pulse laser on the fine grain breaking of the current layer, this embodiment uses TC4 titanium alloy as the test object. Figure 2 As shown in ④, during or after the manufacturing process of each layer, pulsed laser is used to impact strengthen the interface between layers. The strengthening shock wave refines the grains in the material, increases dislocations, and changes the residual stress state in the parts, thereby increasing the strength and hardness of the material, reducing the residual tensile stress in the parts, forming compressive stress in the shallow surface layer, and improving the mechanical properties of the material. The experimental results show that the hardness of the TC4 titanium alloy is increased from 360HV to 430HV after strengthening, and the compressive stress is not less than 100Mpa.

[0107] Since the current layer of material cools too quickly, it will cause unnecessary residual stress inside the material. Therefore, in the process of forming laser manufacturing the current layer, continuous laser and / or pulse laser are used to act on the current layer at the same time to perform heat treatment on the current layer material, so as to reduce the residual stress inside the current layer material through the heat treatment effect.

[0108] Specifically, a 1000-8000W continuous laser or a pulse width of 0.1fs-100ns, a repetition frequency of 10-3000kHz, and a single pulse energy of 0.1μJ-50mJ pulse laser is used on the formed parts or simultaneously with the forming laser during the forming process to heat treat the current layer of material, control the cooling process of the material to obtain the required tissue composition, or heat the material to near the annealing temperature to reduce the residual stress of the material.

[0109] In this embodiment, the parameters of the pulse laser are: single pulse energy 1 μJ-20 mJ, repetition frequency 10-3000 kHz, pulse width 0.1 fs-1 s, spot size 10-100 μm, and number of pulse spots 1-10.

[0110] The above-mentioned pulse laser parameter combination has an impact on the processing depth, surface roughness, surface material composition, surrounding material organization, surface morphology and residual stress of the material surface. For this purpose, a corresponding database is established, and the corresponding processing parameters are directly obtained from the corresponding database according to specific needs.

[0111] In this embodiment, the parameters of the continuous laser are: laser power 50~5000W, spot size 0.05~10mm, and the formed beam shape includes one of square, elliptical, circular, ring, triangle, spindle, linear, arc, and petal shapes, or a combination of any two or more.

[0112] The continuous laser forming parameter range is determined through experiments: the laser power ranges from 50 to 5000 W, the spot size is 0.05 to 10 mm through beam shaping, the beam shapes include (square, elliptical, circular, annular, triangular, spindle, linear, arc, petal, etc.), or multiple circular, square or rectangular continuous spots with a spot size of 0.05 to 2 mm are combined to form spots of other shapes, and the forming quality, forming temperature field and internal tissue distribution after forming of the above spots under different parameters are measured, and these data are stored to facilitate the subsequent rapid acquisition of corresponding processing data based on experience.

[0113] For example, for parts with high fatigue performance requirements, the interlayer interface is heat treated with a large spot laser with a power of 200 to 10,000 W during the manufacturing process, and the pulse laser with a power of 10 to 200 W, a pulse width of 0.01 to 10 ps, ​​and a repetition rate of 10 to 1000 kHz is strengthened for 0.1 to 180 seconds. The interlayer interface and the final surface of the part are heat treated and impact strengthened, so that the grains are refined, the dislocations are increased, and compressive stress is formed, the material hardness is increased, and the residual tensile stress is reduced. Heat treatment can also be used to adjust the phase composition in the material, control the distribution of the microstructure, and eliminate the overall heat treatment after the additive manufacturing is completed, so as to allocate the material organization and performance on demand and realize the direct manufacturing of high-performance parts. Experiments show that the hardness of titanium alloys can be increased from 360HV to 430HV, and the surface stress is changed from tensile stress of more than 200Mpa to compressive stress of not less than 100Mpa.

[0114] like Figure 3 As shown, the hardness of the current layer material is increased from 350HV to 420HV and the grain size is reduced by 50%.

[0115] like Figure 4 As shown, the residual stress changes from tensile stress to compressive stress.

[0116] like Figure 5 As shown, the compressive stress increases by 12%.

[0117] Example 3

[0118] For ease of understanding, an embodiment of the all-laser additive and subtractive composite manufacturing method is provided below for illustration. On the basis of Example 1, since some defects on the surface of the current layer will affect the entire mechanical properties of the current layer, after the current layer is completed, a pulsed laser is used to perform the following processing on the current layer: first, a nanosecond laser is used to perform rough processing on the side surface of the current layer to remove the powder adhering to the surface of the current layer, and then a picosecond laser is used to perform fine processing on the edge of the current layer to improve the surface quality of the current layer, and finally, a femtosecond laser is used to texturize the surface to obtain a functional surface. At the same time, a picosecond or nanosecond laser with a Gaussian or Bessel spot is used to punch or groove the internal holes or groove structures to achieve high-quality direct manufacturing of the internal structure.

[0119] For difficult-to-process materials such as high-temperature alloys, cemented carbides, and titanium alloys, the side and lower surfaces are difficult to process due to the complex structure of additive manufacturing parts and the difficulty of mechanical processing, and the tool wear is large. In the additive manufacturing process, the side and lower surfaces are rough-processed with a power of 30W to 500W, a speed of 50mm / s to 3000mm / s, and a spot size of 0.5mm to 3mm continuous laser, and a power of 30W to 1000W, a speed of 50mm / s to 4000mm / s, and a spot size of 0.5mm to 3mm nanosecond laser to remove surface sticky powder; then use a power of 10W to 200W, a pulse width of 1ps to 10ps, and a repetition rate of 10kHz to 1000 kHz, speed 10mm / s~2000mm / s picosecond laser is used for fine polishing to improve the surface quality; finally, femtosecond laser with power 10W~200W, pulse width 1fs~100fs, repetition rate 10kHz~1000kHz and speed 10mm / s~2000mm / s is used to perform microstructure processing on the surface to form a functional surface with structures such as micropores, micropillars, microgrooves, and microripples, ultimately realizing the direct manufacturing of surface processing and surface functionalization of complex parts.

[0120] Implement the above operations in Figure 2 Among the parts shown, Figure 2 As shown in ②, nanosecond, picosecond or femtosecond laser is used to cut the formed side surface of the part, such as Figure 2 As shown in Experimental Results 2-1, the side surface is first rough-processed using a nanosecond laser to quickly remove surface defects such as powder sticking and slag, and then the surface is fine-processed using a picosecond laser to obtain a high surface quality of Ra<1; finally, the surface is functionalized using a femtosecond laser to form a functional surface on the side surface.

[0121] Example 4

[0122] For ease of understanding, an embodiment of the all-laser additive and subtractive composite manufacturing method is provided below for illustration. Based on Embodiment 1, due to the problems of poor bonding strength and many crack defects at the interface between the layers, after the current layer is completed, a pulsed laser is used to process the micro-nano structure on the surface of the current layer so that the next layer is connected to the micro-nano structure of the current layer.

[0123] Pulsed lasers are used to process the forming interface or final surface to form micro-nano textures such as cones, squares, cylinders, grooves, waves, holes, etc. The absorption of lasers and the flow characteristics of the molten pool are changed through micro-nano textures, thereby improving the uniformity of powder distribution, laser absorption rate, spatter splashing process and flow stability of the molten pool, and achieving the effect of tissue growth induction and refinement during the cooling process. It not only improves the internal quality of the parts, but also improves the connection stability of the interface between layers.

[0124] Implement the above operations in Figure 2 Among the parts shown, Figure 2 As shown in ③, during or after the manufacturing process of each layer, a pulsed laser is used to process the interface between layers to form a micro-texture 3-1 below the micron level or a micro-structure 3-2 at the micron level (including but not limited to micro-pillars, grooves, micro-pores and other structures). The above structure improves powder distribution, reduces powder splashing, changes interface light absorption and scattering conditions, improves interlayer interface bonding, improves the bonding force of dissimilar materials, thereby reducing defects, changing microstructure distribution, controlling the internal structure distribution of parts, and achieving high-performance parts manufacturing.

[0125] Example 5

[0126] For ease of understanding, an embodiment of the full laser additive and subtractive composite manufacturing method is provided below for illustration. Based on Embodiment 1, after the part is formed, the surface of the part is laser polished or subjected to surface microstructure treatment to achieve surface functionalization of the part.

[0127] After the final forming surface of the part is manufactured, the final surface of the part is laser polished or post-processed with surface microstructures to make the surface roughness reach within Ra1, or to form surface microstructures such as super-hydrophobicity, super-hydrophilicity, antibacterial, cell adhesion, structured light, directional liquid transport, etc., to achieve surface functionalization of the part.

[0128] Implement the above operations in Figure 2 Among the parts shown, Figure 2 As shown in ①, continuous, nanosecond, picosecond or femtosecond laser is used to polish or functionalize the final upper surface, side surface and lower surface of the part. Experimental result 1-1 shows that the roughness of the upper surface, side surface and lower surface of laser additive manufacturing can be reduced to below Ra0.5; experimental result 1-2 shows that laser processing can form microstructures such as microgrooves, microcones, microcolumns and micropores on the upper surface, side surface and lower surface, realizing surface super-hydrophobicity, super-hydrophilicity, antibacterial, high evaporation, directional transport and other functions.

[0129] Example 6

[0130] This embodiment discloses a full laser additive and subtractive composite manufacturing device, such as Figure 1 As shown, the device is applied to the all-laser additive and subtractive composite manufacturing method of the above embodiment, and the device includes:

[0131] The optical system 1 includes a first laser unit and a second laser unit. In practical applications, there may be multiple laser units. Each laser unit includes a pulse laser module and a continuous laser module. The lasers in each module can operate individually or simultaneously.

[0132] A galvanometer 2, wherein the galvanometer 2 is connected to the pulse laser 3 of the pulse laser module and the continuous laser 6 of the continuous laser module in the first laser unit,

[0133] A processing head 4 is connected to the pulse laser 3 of the pulse laser module and the continuous laser 6 of the continuous laser module in the second laser unit. A coaxial powder feeding structure is provided in the processing head, so that powder can be spread and processing can be performed at the same time in the processing head. The processing head is a multi-degree-of-freedom processing head. Exemplarily, the processing head has five degrees of freedom. In actual applications, it can also have other degrees of freedom.

[0134] In this embodiment, it also includes a molding cylinder 7 and a powder spreading mechanism 13. The molding cylinder 7 is arranged below the galvanometer 2 and the processing head 4. The powder spreading mechanism 13 is located on the side of the molding cylinder 7. The molding cylinder 7 is connected to a flipping mechanism 9, and the flipping mechanism 9 drives the molding cylinder 7 to rotate.

[0135] In this embodiment, a multi-axis guide rail 5 is arranged above the forming cylinder 7 , and the processing head 4 is arranged on the multi-axis guide rail 5 .

[0136] The working principle of the above-mentioned all-laser additive and subtractive composite manufacturing device is as follows: Figure 1 As shown, a full laser additive and subtractive composite manufacturing device. The optical system 1 is equipped with multiple lasers, and the multiple lasers transmit corresponding light to the device according to the process requirements. The forming area can be scanned, formed and processed using a galvanometer 2, or the part can be processed and formed from different angles and orientations using a multi-axis processing head 4, and the processing head can move on a multi-axis guide rail 5. Both the galvanometer 2 and the processing head 4 can use pulsed lasers 3 and continuous lasers 6 with different pulse widths. The part 12 can be formed using a powder bed method, and the powder is in the forming cylinder 7, and moves up and down through the lifting platform 8 and the driving device 11. The forming platform can also be formed on the platform substrate around the horizontal axis or vertical axis driven by the flip mechanism 9 and the rotating platform 10, and the workpiece is separated from the substrate after completion. The powder spreading mechanism 13 can spread the powder during the forming process. The forming and processing process is controlled by the control system and the computer 14.

[0137] Since the above-mentioned all-laser additive and subtractive composite manufacturing device combines continuous laser and pulsed laser, it can ultimately complete the direct manufacturing of parts in one device, forming complex components with good internal and external quality, few defects, controllable tissue distribution, controllable performance and functional surfaces. The process data is stored in the database and compared with the service status of the parts. The forming and manufacturing process is monitored and fed back according to the service process of the parts to optimize the forming and strengthening parameters.

[0138] It can be seen that a variety of continuous lasers are integrated with pulsed lasers, and they can be used separately or simultaneously to perform manufacturing, polishing, processing, strengthening, heat treatment and surface functionalization. Pulsed lasers with various pulse widths perform rough processing, fine processing and surface functionalization on the surface of parts, and realize the direct manufacturing of ordinary and precision microstructure parts (such as micropores, thin walls, and microchannels). Use methods such as spot shaping, pulsed laser processing, impact strengthening, and laser heat treatment to strengthen the interface, improve the interface bonding ability, achieve organizational control, regulate residual stress, and improve part performance.

[0139] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0140] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0141] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0142] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A full laser additive and subtractive composite manufacturing method, characterized in that: By switching between pulsed laser and continuous laser processing of the current layer, the current layer can be processed by additive and subtractive material. The additive and subtractive material processing process can change the interface morphology material and internal tissue distribution of the current layer, and the formed interface layer can regulate the flow state and internal stress of the molten pool in the subsequent additive process, thereby achieving the effect of inducing and refining tissue growth.

2. The all-laser additive and subtractive composite manufacturing method according to claim 1, characterized in that: The pulse laser energy is regulated to ablate the current layer so that the current layer forms a micro-nano structure, and the next forming layer is formed on the micro-nano structure of the current layer, or the pulse laser energy is regulated to ablate the surface of the part so that the surface of the part has a functional structure.

3. The all-laser additive and subtractive composite manufacturing method according to claim 1, characterized in that: The pulse laser energy is regulated to ablate the current layer, so that the pulse laser generates shock waves and compressive stress in the current layer. The shock waves and the compressive stress change the grain size and morphology of the current layer, and dislocations are formed inside the current layer.

4. The all-laser additive and subtractive composite manufacturing method according to claim 1, characterized in that: Regulate the continuous laser energy and / or pulsed laser energy to heat the current layer of material once or multiple times, regulate the temperature field distribution and change rate of the material, and reduce the residual stress inside the material.

5. The all-laser additive and subtractive composite manufacturing method according to claim 1, characterized in that: Laser polishing of part surfaces using pulsed lasers.

6. The all-laser additive and subtractive composite manufacturing method according to claim 1, characterized in that: A pulse laser of a certain width is selected to remove powder adhering to the surface of the current layer by processing the surface of the current layer with the pulse laser.

7. The all-laser additive and subtractive composite manufacturing method according to claim 1, characterized in that: By machining the interface texture in the interface layer, the cooling process of the molten pool induces growth and refines the material structure.

8. The all-laser additive and subtractive composite manufacturing method according to claim 1, characterized in that: The interface morphology of the material is formed by laser induction or processing.

9. The all-laser additive and subtractive composite manufacturing method according to claim 1, characterized in that: The hydrophilicity and hydrophobicity of the material's interface surface can be regulated by adjusting continuous laser or pulse parameters.

10. The all-laser additive and subtractive composite manufacturing method according to claim 1, characterized in that: The surface polishing of formed parts and the removal of peripheral burrs are achieved by adjusting continuous laser or pulse parameters.

11. The all-laser additive and subtractive composite manufacturing method according to any one of claims 1 to 10, characterized in that: The parameters of the pulse laser are: laser wavelength 200nm-20000nm, single pulse energy 1μJ-20mJ, repetition frequency 10kHz-3000kHz, pulse width 0.1fs-1s, spot size 10μm-100μm, and number of pulse spots 1-10.

12. The all-laser additive and subtractive composite manufacturing method according to any one of claims 1 to 10, characterized in that: The parameters of the continuous laser are: laser wavelength 200nm-20000nm, laser power 50W-5000W, and spot size 0.05mm-10mm.

13. The all-laser additive and subtractive composite manufacturing method according to any one of claims 1 to 10, characterized in that: The laser spot shape includes one of square, ellipse, circle, ring, triangle, spindle, line, arc, petal shape or a combination of any two or more.

14. The all-laser additive and subtractive composite manufacturing method according to claim 1, characterized in that: The pulse laser performs milling, turning and drilling on the current layer, so as to form channels and precise microstructures (micropores, thin walls and microstructures) in the current layer.

15. The all-laser additive and subtractive composite manufacturing method according to claim 1, characterized in that: The material of the current layer is one of powder material, filament material, block material, liquid material or any combination thereof.

16. The all-laser additive and subtractive composite manufacturing method according to claim 15, characterized in that: The material is a composite material of organic matter, ceramic, simple metal or alloy or any combination thereof.

17. The all-laser additive and subtractive composite manufacturing method according to claim 16, characterized in that: The elemental metal includes pure copper, The alloy includes one or a combination of any multiple of cemented carbide, stainless steel, titanium alloy, high-temperature alloy, die steel, and Hastelloy.

18. A full laser additive and subtractive composite manufacturing device, characterized in that: The device is applied to the all-laser additive and subtractive composite manufacturing method according to any one of claims 1 to 17, and the device comprises: An optical system comprises a pulse laser module and a continuous laser module, wherein the pulse laser module and the continuous laser module are configured to operate separately or simultaneously.

19. The all-laser additive and subtractive composite manufacturing device according to claim 18, characterized in that: It also includes an online monitoring closed-loop manufacturing parameter control module, and the pulse laser module and the continuous laser module are respectively connected to the online monitoring closed-loop manufacturing parameter control module.

20. The all-laser additive and subtractive composite manufacturing device according to claim 18, characterized in that: It also includes a galvanometer, which is connected to the pulse laser module optical path and the continuous laser module optical path respectively.

21. The all-laser additive and subtractive composite manufacturing device according to claim 18, characterized in that: It also includes a processing head, which is provided with an optical path outlet, and the optical path outlet conducts the pulse laser module optical path and the continuous laser module optical path.

22. The all-laser additive and subtractive composite manufacturing device according to claim 21, characterized in that: The processing head is provided with a coaxial feeding structure, and the coaxial feeding structure is used to convey the processing material, and the feeding direction of the coaxial feeding structure is the same as the processing direction of the processing head.

23. The all-laser additive and subtractive composite manufacturing device according to claim 22, characterized in that: The coaxial feeding structure is a coaxial powder feeding structure or a coaxial wire feeding structure.

24. The all-laser additive and subtractive composite manufacturing device according to claim 21, characterized in that: The processing head is a multi-degree-of-freedom processing head.

25. The all-laser additive and subtractive composite manufacturing device according to claim 21, characterized in that: It also includes a molding cylinder and a powder spreading mechanism. A multi-axis guide rail is arranged above the molding cylinder. The processing head is connected to the multi-axis guide rail. The multi-axis guide rail controls the processing angle of the processing head.

26. The all-laser additive and subtractive composite manufacturing device according to claim 18, characterized in that: It also includes a processing table, which is a multi-station processing table, and each station is used to process a part; Or the processing table is a mobile processing table, and the mobile processing table drives the parts to move and be processed by each laser; Or the processing table is a co-position processing table, and the co-position processing table processes multiple parts in parallel.

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