CN113427020A - Laser powder bed melting additive manufacturing method based on multiple scanning melting - Google Patents

Laser powder bed melting additive manufacturing method based on multiple scanning melting Download PDF

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CN113427020A
CN113427020A CN202110692790.4A CN202110692790A CN113427020A CN 113427020 A CN113427020 A CN 113427020A CN 202110692790 A CN202110692790 A CN 202110692790A CN 113427020 A CN113427020 A CN 113427020A
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alloy
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CN113427020B (en
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温鹏
刘金戈
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Tsinghua University
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F10/00Additive manufacturing of workpieces or articles from metallic powder
    • B22F10/20Direct sintering or melting
    • B22F10/28Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F10/00Additive manufacturing of workpieces or articles from metallic powder
    • B22F10/30Process control
    • B22F10/36Process control of energy beam parameters
    • B22F10/366Scanning parameters, e.g. hatch distance or scanning strategy
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F10/00Additive manufacturing of workpieces or articles from metallic powder
    • B22F10/80Data acquisition or data processing
    • B22F10/85Data acquisition or data processing for controlling or regulating additive manufacturing processes
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B33ADDITIVE MANUFACTURING TECHNOLOGY
    • B33YADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y10/00Processes of additive manufacturing
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B33ADDITIVE MANUFACTURING TECHNOLOGY
    • B33YADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
    • B33Y50/00Data acquisition or data processing for additive manufacturing
    • B33Y50/02Data acquisition or data processing for additive manufacturing for controlling or regulating additive manufacturing processes
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00Technologies related to metal processing
    • Y02P10/25Process efficiency

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  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Automation & Control Theory (AREA)
  • Powder Metallurgy (AREA)

Abstract

A laser powder bed melting additive manufacturing method based on multiple scanning melting comprises the following steps: the method comprises the following steps: three-dimensional modeling of parts and design of printing strategies: modeling the appearance of the alloy material to be prepared, and designing a printing strategy of applying gradually deflected multiple laser scanning after each layer of paved metal powder so as to realize additive manufacturing; wherein, the laser scanning power is 20-400W, and the scanning speed is 200-; step two: powder and doctor blade pre-setting before printing: presetting metal powder in a powder bin of a printer, presetting a scraper on a focal plane of equipment, and washing the powder bin with protective gas; preheating the substrate according to the characteristics of the alloy material to be prepared after the gas washing is finished; step three: printing of materials and recycling of printed parts: after printing is finished, opening the cabin door after the temperature is cooled to room temperature, and recovering powder in the cabin; and taking out the printed part and the substrate, separating the part from the substrate, and cleaning powder on the surface of the part by using compressed air.

Description

Laser powder bed melting additive manufacturing method based on multiple scanning melting
Technical Field
The invention belongs to the field of material processing engineering, and particularly relates to a laser powder bed melting additive manufacturing method based on multiple scanning melting.
Background
Laser Powder Bed Fusion (LPBF) uses a high energy density laser beam to fuse discrete metal powders together by a multi-pass multi-layer scanning fusion method to form a three-dimensional entity. The laser heating is accurate, the powder is fine and dense, the powder bed does not need rigid support, the high-precision forming of a complex structure can be realized, the density of a formed piece is high, the mechanical property is good, and the laser powder bed has wide application prospects in the fields of aerospace, medical instruments and the like. The laser scanning speed of LPBF is increased, the cooling and solidification speed of a molten pool can be increased, on one hand, the grain refining effect is obtained, and the mechanical property of a formed part is improved; on the other hand, the precipitation and growth of the second phase are reduced, which is beneficial to obtaining a structure far away from the equilibrium state and may bring special performance. However, an increase in the scanning speed leads to a decrease in heat input, and is liable to form defects such as unfusion; in order to ensure the fusing effect of the powder, generally speaking, increasing the scanning speed requires increasing the laser power, and at this time, the effect of rapid cooling is weakened, but the higher laser power can cause excessive evaporation of the metal, and the void defect is easily increased. Therefore, for the general LPBF process, the scanning speed is not suitable to be too fast, otherwise it is difficult to obtain the tissue regulation effect at a high cooling speed. The melting point and the boiling point of magnesium and zinc are low, the magnesium alloy and the zinc alloy are violently evaporated when being melted by laser, the high evaporation tendency not only further limits the improvement of the scanning speed, but also brings a great deal of burning loss of elements, and causes great change of the components of a formed piece.
In summary, how to obtain the tissue control effect caused by rapid solidification in the process of melting the laser powder bed, and avoid the poor fusion problem caused by single high-speed scanning and the air hole problem caused by single high-power scanning, reduce the thermal stress, and reduce the deformation and crack tendency has become a problem to be solved urgently.
Disclosure of Invention
In order to overcome a series of defects in the prior art, the invention aims to solve the problems and provide a laser powder bed melting additive manufacturing method based on multiple scanning melting, which is characterized by comprising the following steps:
the method comprises the following steps: three-dimensional modeling of parts and design of printing strategies
Modeling the appearance of a metal material to be prepared, and designing a printing strategy of applying gradually deflected multiple laser scanning after each layer of paved metal powder so as to realize additive manufacturing;
wherein, the laser scanning power is 20-400W, and the scanning speed is 200-;
step two: powder and doctor blade pre-placement prior to printing
Presetting metal powder in a powder bin of a printer, presetting a scraper on a focal plane of equipment, and washing the powder bin with protective gas; preheating the substrate according to the characteristics of the alloy material to be prepared after the gas washing is finished;
step three: printing of materials and recycling of printed parts
Printing after the gas washing and preheating are finished;
after the printing process is finished, opening the cabin door after the cabin temperature is cooled to the room temperature, and recovering the powder in the cabin;
and taking the printed part and the substrate out, separating the part and the substrate by wire cutting or a small manual saw, and cleaning powder on the surface of the part by using compressed air.
Preferably, in the step one, the model is modeled into a solid geometric shape or a bracket structure or other self-designed structures, and the model of the solid geometric shape is a cylinder or a cuboid; the model of the bracket structure is a diamond structure or a minimum curved surface structure.
Preferably, in the first step, the thickness of the powder layer is 0.01-0.1mm, the scanning interval is 0.02-0.2mm, and the diameter of the laser spot is 50-120 μm.
Preferably, in the step one, the gradually deflected multiple laser scanning is performed n times of zigzag path scanning after each layer of the metal powder is paved, wherein n is 1-500 according to the expected burning loss amount of the alloy element.
Preferably, in step one, in order to ensure that the heat input of each layer of powder is balanced, a deflection angle of 5-175 degrees is kept between adjacent scanning paths.
Preferably, in the step one, in order to obtain alloy materials with different contents of alloy elements at the same time, the same alloy powder is printed by using different scanning times for different samples in the same batch of printing.
Preferably, in the step one, the number of scanning times is 2-200 respectively.
Preferably, in the step one, the multiple laser scans applying gradual deflection are performed in a line-shaped path or a chessboard path after each layer of the metal powder is paved.
Preferably, in the second step, the particle size of the metal powder is 15-95 μm; washing with argon, helium or nitrogen as shielding gas to control oxygen content below 800ppm, and preheating at 50-300 deg.C.
Preferably, in the third step, during the printing process, a circulating air supply system is needed to blow off the smoke generated by evaporation.
Compared with the prior art, the invention has the following beneficial effects:
1) the invention can realize low-power and high-speed printing, thereby realizing the effect of grain refinement, and indirectly improving the mechanical property, corrosion resistance and other comprehensive properties of the printing material;
2) in the printing process, the thermal stress is lower, so that the solidification crack can be inhibited for an alloy system which has a longer liquefaction interval and is easy to generate the solidification crack, and the surface quality of the material is improved;
3) the invention can realize the regulation and control of the alloy element components and quantitatively control the content of the alloy elements of the material by adjusting the laser scanning times.
Drawings
FIG. 1 is a schematic view of a multiple scanning process of selective laser melting;
FIG. 2 is a schematic diagram of a scanning strategy for applying different laser scanning times to a single layer of powder;
FIG. 3 is a graph showing the calculation of the evaporation flux of Zn, Mg, Fe, Ti at different temperatures using the Langmuir equation;
FIG. 4 is the density variation of WE43 magnesium alloy under different scanning times;
FIG. 5 shows the texture change of a single-scan and multi-scan WE43 magnesium alloy;
FIG. 6 shows the hardness change of WE43 magnesium alloy material under different scanning times;
FIG. 7 shows the change of WE43 magnesium alloy forming quality under different scanning times;
FIG. 8 is a comparison of the metallographic cross-sectional morphology of single-scan and multi-scan ZK60 magnesium alloys;
fig. 9 is a linear fit of the content of the elements of the printed alloy of WE43 magnesium alloy with the number of scans.
Detailed Description
In order to make the implementation objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be described in more detail below with reference to the accompanying drawings in the embodiments of the present invention. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, but not all embodiments of the invention.
All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The embodiments and the directional terms described below with reference to the drawings are exemplary and intended to be used in the explanation of the invention, and should not be construed as limiting the invention.
In one broad embodiment of the invention, a laser powder bed fusion additive manufacturing method based on multiple scan melting is characterized by comprising the steps of:
the method comprises the following steps: three-dimensional modeling of parts and design of printing strategies
Modeling the appearance of a metal material to be prepared, and designing a printing strategy of applying gradually deflected multiple laser scanning after each layer of paved metal powder so as to realize additive manufacturing;
wherein, the laser scanning power is 20-400W, and the scanning speed is 200-;
step two: powder and doctor blade pre-placement prior to printing
Presetting metal powder in a powder bin of a printer, presetting a scraper on a focal plane of equipment, and washing the powder bin with protective gas; preheating the substrate according to the characteristics of the alloy material to be prepared after the gas washing is finished;
step three: printing of materials and recycling of printed parts
Printing after the gas washing and preheating are finished;
after the printing process is finished, opening the cabin door after the cabin temperature is cooled to the room temperature, and recovering the powder in the cabin;
and taking the printed part and the substrate out, separating the part and the substrate by wire cutting or a small manual saw, and cleaning powder on the surface of the part by using compressed air.
Preferably, in the step one, the model is modeled into a solid geometric shape or a bracket structure or other self-designed structures, and the model of the solid geometric shape is a cylinder or a cuboid; the model of the bracket structure is a diamond structure or a minimum curved surface structure.
Preferably, in the first step, the thickness of the powder layer is 0.01-0.1mm, the scanning interval is 0.02-0.2mm, and the diameter of the laser spot is 50-120 μm.
Preferably, in the step one, the gradually deflected multiple laser scanning is performed n times of zigzag path scanning after each layer of the metal powder is paved, wherein n is 1-500 according to the expected burning loss amount of the alloy element.
Preferably, in step one, in order to ensure that the heat input of each layer of powder is balanced, a deflection angle of 5-175 degrees is kept between adjacent scanning paths.
Preferably, in the step one, in order to obtain alloy materials with different contents of alloy elements at the same time, the same alloy powder is printed by using different scanning times for different samples in the same batch of printing.
Preferably, in the step one, the number of scanning times is 2-200 respectively.
Preferably, in the step one, the multiple laser scans applying gradual deflection are performed in a line-shaped path or a chessboard path after each layer of the metal powder is paved.
Preferably, in the second step, the particle size of the metal powder is 15-95 μm; washing with argon, helium or nitrogen as shielding gas to control oxygen content below 800ppm, and preheating at 50-300 deg.C.
Preferably, in the third step, during the printing process, a circulating air supply system is needed to blow off the smoke generated by evaporation.
The present invention will be described in further detail below with reference to the accompanying drawings, which illustrate several preferred embodiments of the present invention.
Preferred embodiment 1
In the preferred embodiment, the laser powder bed melting additive manufacturing method based on multiple scanning melting realizes high-density additive manufacturing with low power and high heat input, and achieves the effects of grain refinement, structure strengthening and surface quality improvement.
Referring to the scanning strategy shown in fig. 1, the preferred embodiment employs a selective laser additive manufacturing printer with a cyclic automatic blower system and substrate preheat function with a maximum power of 500W. The equipment model may be referred to as S-210 manufactured by Siam platinum additive manufacturing technologies, Inc. The alloy powder used in the preferred embodiment was WE43 (Mg-balance, Y-4.01%, Nd-2.4%, Gd-0.6%, Zr-0.51%), and the particle diameter was 15-63 μm.
The printing process used the scheme shown in figure 1, the printing strategy shown in figure 2 was set up, the laser scanning used zigzag paths with a 60 ° deflection angle between each scan path. The laser power is 80W, the scanning speed is 1600mm/s, the scanning interval is 0.07mm, and the powder layer thickness is 0.02 mm. The number of scans used was 1,12,24,36,48, respectively.
Presetting WE43 magnesium alloy powder in a powder bin of a selective laser additive printer, presetting a scraper on a focal plane of equipment, performing gas washing by using argon as a protective gas to control the oxygen content to be below 80ppm, and preheating at 200 ℃; and after preheating is finished, printing is started, and smoke generated by evaporation is blown off by using a circulating air supply system in the printing process. After printing, open the hatch door after cabin temperature cools to the room temperature, retrieve and carry out the sieve powder to the powder in the cabin, use the vacuum bag to preserve so that the secondary use. And taking the printed part and the substrate out, separating the part from the substrate by using a clamp, and placing the part in alcohol for ultrasonic cleaning.
The density of the material of the samples with different scanning times after ultrasonic cleaning is observed by using an optical lens, meanwhile, the density is subjected to image binarization statistics by using MATLAB, and the observation result is shown in FIG. 4. When only one-time laser scanning is used, the laser power is 80W, the scanning speed is 1600mm/s, the heat input is too low, the material cannot be fully melted, the density is only 98.03, when the laser scanning is carried out for 12 times, the heat accumulation is generated by multiple times of laser scanning on single-layer powder, the powder is fully melted and spread, and the density is increased to 99.82%. When the number of laser scanning times is increased again, the density of the material is further increased, but the increasing trend is gradually reduced. Experimental results show that the compactness of more than 99.9 percent can be obtained by using multiple times of scanning. In addition, in order to verify the effect of grain refinement, a single-scanning (80W, 800mm/s, one time) material structure and a multi-scanning (80W, 800mm/s, 48 times) structure with the density of more than 99.9% are observed by an electron microscope, such as that shown in fig. 5. It can be seen that the grains are significantly refined by the multiple scans due to the faster cooling rate. The hardness of the material with different scanning times is tested as shown in fig. 6, and the hardness of the material is obviously improved along with the improvement of the scanning times, which shows that the obvious fine grain strengthening effect is generated by multiple times of scanning. Further, the surface of the material was observed at different scan times, as shown in fig. 7. Along with the increase of the scanning times, the surface powder adhesion of the material is obviously improved, and the surface quality of the material is improved.
Preferred embodiment 2
In the preferred embodiment, the Mg-Zn-Zr alloy with different components is realized by applying different times of selective laser scanning, so that the effect of inhibiting the liquefaction cracks is achieved.
Referring to the scanning strategy shown in fig. 1, the preferred embodiment employs a selective laser additive manufacturing printer with a cyclic automatic blower system and substrate preheat function with a maximum power of 500W. The equipment model may be referred to as S-210 manufactured by Siam platinum additive manufacturing technologies, Inc. The alloy powder used in the preferred embodiment is ZK60 (Mg-balance, Zn-5.6%, Zr-0.5%), and has a particle size of 15-63 μm.
The printing process adopts the scheme shown in FIG. 1 to set the printing strategy shown in FIG. 2, the laser scanning adopts zigzag paths, the deflection angle of 60 degrees is adopted between every two scanning paths, the scanning interval is 0.07mm, and the powder layer thickness is 0.02 mm. The laser power of single scanning is 90W, the scanning speed is 800mm/s, the laser power of multiple scanning is 80W, the scanning speed is 1600mm/s, and the scanning times are 6 times.
Presetting ZK60 magnesium alloy powder in a powder bin of a selective laser additive printer, presetting a scraper on a focal plane of equipment, performing gas washing by using argon as a protective gas to control the oxygen content below 80ppm, and preheating at 200 ℃; and after preheating is finished, printing is started, and smoke generated by evaporation is blown off by using a circulating air supply system in the printing process. After printing, open the hatch door after cabin temperature cools to the room temperature, retrieve and carry out the sieve powder to the powder in the cabin, use the vacuum bag to preserve so that the secondary use. And taking the printed part and the substrate out, separating the part from the substrate by using a clamp, and placing the part in alcohol for ultrasonic cleaning.
The single-scanning and multi-scanning ZK60 samples were observed under an electron microscope, and the results are shown in FIG. 8. The sample prepared by single scanning generates larger thermal stress between printing layers due to the overhigh laser heat input. Meanwhile, the magnesium ZK60 alloy has a large liquefaction interval (310 ℃) and a high hot cracking tendency, so that severe hot cracking is generated under the influence of high thermal stress. The multiple scanning process provided by the invention can effectively reduce the thermal stress, and as shown in fig. 8, when the multiple scanning printing process is used, the generation of thermal cracks is effectively inhibited.
Preferred embodiment 3
The preferred embodiment realizes the regulation and control of the alloy elements of the material through the melting additive manufacturing of the laser powder bed of multiple scanning melting.
Referring to the scanning strategy shown in fig. 1, the preferred embodiment employs a selective laser additive manufacturing printer with a cyclic automatic blower system and substrate preheat function with a maximum power of 500W. The equipment model may be referred to as S-210 manufactured by Siam platinum additive manufacturing technologies, Inc. The alloy powder used in the preferred embodiment was WE43 (Mg-balance, Y-4.01%, Nd-2.4%, Gd-0.6%, Zr-0.51%), and the particle diameter was 15-63 μm.
The printing process used the scheme shown in figure 1 to set up a printing strategy as shown in figure 2, with the laser scanning using zigzag paths with a 60 ° deflection angle between each scan path. The laser power was 80W, the scanning speed was 800mm/s, the scanning pitch was 0.07mm, and the powder layer thickness was 0.02 mm. The number of scans used was 1,2,4,6,10, respectively.
Presetting WE43 magnesium alloy powder in a powder bin of a selective laser additive printer, presetting a scraper on a focal plane of equipment, performing gas washing by using argon as a protective gas to control the oxygen content to be below 80ppm, and preheating at 200 ℃; and after preheating is finished, printing is started, and smoke generated by evaporation is blown off by using a circulating air supply system in the printing process. After printing, open the hatch door after cabin temperature cools to the room temperature, retrieve and carry out the sieve powder to the powder in the cabin, use the vacuum bag to preserve so that the secondary use. And taking the printed part and the substrate out, separating the part from the substrate by using a clamp, and placing the part in alcohol for ultrasonic cleaning.
EDS (electron-dispersive spectroscopy) elemental spectrum analysis was performed on samples subjected to ultrasonic cleaning at different scanning times, and the changes in the alloy element components of the WE43 magnesium alloy at different scanning times are shown in Table 1. As can be seen from the table, the alloying element content of the material changed significantly. The content of Mg element with larger evaporation tendency is obviously reduced, and the content of other alloy elements with small evaporation tendency is gradually increased. Assuming that the evaporation amount of the alloy element generated by each laser scanning is the same, linear fitting is carried out on the element content of the WE43 magnesium alloy under different scanning times by using linear fitting, and the change of the main element content along with the scanning times is shown in the following formula. Quantitative prediction is carried out on the change of the content of the WE43 alloy element in 0-30 times of scanning, and the result is shown in figure 9. The adjustment and control of the alloy element components of the printing material can be realized through multiple scanning, and meanwhile, the influence of the multiple scanning on the alloy element components can be quantitatively predicted through an experimental measurement and fitting mode.
Mg:y=-0.7729x+93.0793
Y:y=0.4116x+2.0386
Nd:y=0.2130+2.3823
Gd:y=0.0939x+1.098
Table 1: variation of percentage of printing material components at different scan times
Figure BDA0003126801390000071
In summary, the main applications of the present invention include, but are not limited to, the following four:
1. the material crystal grains are refined, and the comprehensive performance of the material is improved: in the selective laser additive manufacturing process, the low-power and high-speed laser scanning is beneficial to grain refinement and residual stress reduction due to the higher cooling speed, however, in the traditional laser powder bed melting technology, the low-power and high-speed laser scanning has the defect of non-fusion due to too low heat input, and even the material cannot be molded. The laser powder bed melting additive manufacturing method adopting multi-scanning melting provided by the invention has the advantages that heat accumulation exists among multiple laser scans of the same layer of powder, and the test result proves that high-density printing with low-power and high-speed laser scanning can be realized. The high scanning speed has a higher cooling speed, so that the material obtained by the method has obviously refined grains.
2. And (3) inhibition of solidification cracking: for an alloy system with a large liquefaction interval, a conventional laser powder bed melting additive manufacturing mode is easy to generate large thermal stress, so that low-melting-point eutectic precipitated at a grain boundary is torn to generate liquefaction cracks. The melting additive manufacturing method of the laser powder bed with multiple scanning melting provided by the invention can realize printing with low power and high scanning speed, reduce the thermal stress in the printing process and inhibit the generation of solidification cracks.
3. The surface quality is improved: the multiple scanning strategy adopted by the invention can fully melt the powder at the edge of the printed part, and the effect of improving the surface quality is achieved.
4. Regulating and controlling the components of alloy elements: the evaporation flux of several common alloy material components at different temperatures was calculated using the Langmuir equation, and the results are shown in fig. 3. At the same temperature, the evaporation amount of elements with higher evaporation tendency of Zn, Mg and the like is obviously higher than that of elements with lower evaporation tendency of Fe, Ti and the like. Therefore, the invention enlarges the evaporation tendency difference by scanning each layer of powder for a plurality of times, and realizes the regulation and control of the alloy element components of the printing material.
Finally, it should be pointed out that: the above examples are only for illustrating the technical solutions of the present invention, and are not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (10)

1. A laser powder bed melting additive manufacturing method based on multiple scanning melting is characterized by comprising the following steps:
the method comprises the following steps: three-dimensional modeling of parts and design of printing strategies
Modeling the appearance of a metal material to be prepared, and designing a printing strategy of applying gradually deflected multiple laser scanning after each layer of paved metal powder so as to realize additive manufacturing;
wherein, the laser scanning power is 20-400W, and the scanning speed is 200-;
step two: powder and doctor blade pre-placement prior to printing
Presetting metal powder in a powder bin of a printer, presetting a scraper on a focal plane of equipment, and washing the powder bin with protective gas; preheating the substrate according to the characteristics of the alloy material to be prepared after the gas washing is finished;
step three: printing of materials and recycling of printed parts
Printing after the gas washing and preheating are finished;
after the printing process is finished, opening the cabin door after the cabin temperature is cooled to the room temperature, and recovering the powder in the cabin;
and taking the printed part and the substrate out, separating the part and the substrate by wire cutting or a small manual saw, and cleaning powder on the surface of the part by using compressed air.
2. The manufacturing method according to claim 1, wherein in the first step, the model is modeled as a solid geometric shape or a stent structure or other autonomously designed structure, and the model of the solid geometric shape is a cylinder or a cuboid; the model of the bracket structure is a diamond structure or a minimum curved surface structure.
3. The manufacturing method according to claim 1, wherein in the first step, the thickness of the powder layer is 0.01 to 0.1mm, the scanning pitch is 0.02 to 0.2mm, and the diameter of the laser spot is 50 to 120 μm.
4. The method according to claim 1, wherein in step one, the gradually deflecting multiple laser scans are performed n times of zigzag path scanning after each layer of the metal powder is coated, wherein n is 1-500 according to the expected burning loss of the alloy element.
5. The method of claim 4, wherein in step one, in order to ensure uniform heat input per scan of each layer of powder, a deflection angle of 5-175 degrees is maintained between adjacent scan paths.
6. The manufacturing method according to claim 4 or 5, wherein in the first step, in order to obtain the alloy materials with different contents of the alloy elements at the same time, the same alloy powder is printed by using different scanning times for different samples in the same batch of printing.
7. The manufacturing method according to claim 6, wherein in the first step, the number of scanning times is 2 to 200.
8. The method according to claim 1, wherein in step one, the multiple laser scans with gradually deflecting are performed in a line-shaped path or a chessboard path scan after each layer of the metal powder is spread.
9. The manufacturing method according to claim 1, wherein in the second step, the particle diameter of the metal powder is 15 to 95 μm; washing with argon, helium or nitrogen as shielding gas to control oxygen content below 800ppm, and preheating at 50-300 deg.C.
10. The manufacturing method of claim 1, wherein in the third step, the smoke generated by evaporation needs to be blown off by using a circulating air supply system during the printing process.
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Cited By (12)

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CN114262830A (en) * 2021-12-14 2022-04-01 沈阳工业大学 Powder for laser 3D printing of light high-strength magnesium alloy and preparation method thereof
CN114288471A (en) * 2021-12-31 2022-04-08 清华大学 Magnesium alloy medical implant and preparation method thereof
CN114505498A (en) * 2022-04-19 2022-05-17 济南森峰激光科技股份有限公司 Laser rapid prototyping method and device easy for entity separation
CN114523125A (en) * 2022-03-01 2022-05-24 中国钢研科技集团有限公司 Method for preparing alloy block through SLM (selective laser melting) in-situ alloying
CN114734057A (en) * 2022-04-24 2022-07-12 重庆理工大学 Laser melting 3d printing method based on metal powder
CN114799212A (en) * 2022-06-17 2022-07-29 暨南大学 Method for inhibiting thermal cracking of laser additive manufacturing nickel-based high-temperature alloy
TWI803154B (en) * 2022-01-18 2023-05-21 台鋼航太積層製造股份有限公司 Method for manufacturing a target material
CN116144962A (en) * 2023-04-17 2023-05-23 北京科技大学 High-strength and high-toughness hastelloy and preparation process thereof
CN116871532A (en) * 2023-07-27 2023-10-13 重庆大学 Laser powder bed molten magnesium rare earth alloy high-strength and toughness preparation method based on cryogenic treatment
CN117066527A (en) * 2023-09-13 2023-11-17 之江实验室 Printing method for regulating and controlling wear resistance of robot foot joint through interlayer orientation induction
CN117161404A (en) * 2023-07-11 2023-12-05 哈尔滨工业大学 Thermal treatment method of as-deposited WE43 magnesium alloy
CN117282986A (en) * 2023-10-25 2023-12-26 之江实验室 Printing method for regulating and controlling wear resistance of sole of robot through directional texture and workpiece

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Publication number Priority date Publication date Assignee Title
CN114262830A (en) * 2021-12-14 2022-04-01 沈阳工业大学 Powder for laser 3D printing of light high-strength magnesium alloy and preparation method thereof
CN114288471A (en) * 2021-12-31 2022-04-08 清华大学 Magnesium alloy medical implant and preparation method thereof
TWI803154B (en) * 2022-01-18 2023-05-21 台鋼航太積層製造股份有限公司 Method for manufacturing a target material
CN114523125A (en) * 2022-03-01 2022-05-24 中国钢研科技集团有限公司 Method for preparing alloy block through SLM (selective laser melting) in-situ alloying
CN114523125B (en) * 2022-03-01 2023-11-07 中国钢研科技集团有限公司 Method for preparing alloy block by SLM in-situ alloying
CN114505498A (en) * 2022-04-19 2022-05-17 济南森峰激光科技股份有限公司 Laser rapid prototyping method and device easy for entity separation
CN114734057A (en) * 2022-04-24 2022-07-12 重庆理工大学 Laser melting 3d printing method based on metal powder
CN114799212A (en) * 2022-06-17 2022-07-29 暨南大学 Method for inhibiting thermal cracking of laser additive manufacturing nickel-based high-temperature alloy
CN116144962A (en) * 2023-04-17 2023-05-23 北京科技大学 High-strength and high-toughness hastelloy and preparation process thereof
CN117161404A (en) * 2023-07-11 2023-12-05 哈尔滨工业大学 Thermal treatment method of as-deposited WE43 magnesium alloy
CN116871532A (en) * 2023-07-27 2023-10-13 重庆大学 Laser powder bed molten magnesium rare earth alloy high-strength and toughness preparation method based on cryogenic treatment
CN116871532B (en) * 2023-07-27 2024-10-11 重庆大学 Laser powder bed molten magnesium rare earth alloy high-strength and toughness preparation method based on cryogenic treatment
CN117066527A (en) * 2023-09-13 2023-11-17 之江实验室 Printing method for regulating and controlling wear resistance of robot foot joint through interlayer orientation induction
CN117066527B (en) * 2023-09-13 2024-06-07 之江实验室 Printing method for regulating and controlling wear resistance of robot foot joint through interlayer orientation induction
CN117282986A (en) * 2023-10-25 2023-12-26 之江实验室 Printing method for regulating and controlling wear resistance of sole of robot through directional texture and workpiece
CN117282986B (en) * 2023-10-25 2024-05-10 之江实验室 Printing method for regulating and controlling wear resistance of sole of robot through directional texture and workpiece

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