Selective laser melting additive manufacturing method for transition fusion of heterogeneous material interface

Abstract

The invention discloses a selective laser melting additive manufacturing method for transition fusion of a heterogeneous material interface, which belongs to the technical field of additive manufacturing and comprises the following steps: S1, inputting data and slicing to generate trajectory data and material components of each layer of slice of a three-dimensional model; s2, laser parameters, powder discharging parameters of a powder discharging mechanism and tiling working parameters of a tiling mechanism are set; s3, the selective laser melting additive manufacturing device uses one of the two kinds of single powder to conduct laser printing on the k layers of slices of the bottom section; s4, the selective laser melting additive manufacturing device uses the mixed powder to conduct laser printing on the m layers of slices of the transition section; and S5, the selective laser melting additive manufacturing device uses the other one of the two kinds of single powder to conduct laser printing on the q-layer slices of the top section.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to a selective laser melting additive manufacturing method for transition fusion of heterogeneous materials at the interface. Background Art

[0002] In recent years, metal additive manufacturing technology has developed rapidly, with widespread applications in aerospace, automotive, and medical fields. With the rapid development of additive manufacturing technology, people have increasingly stringent performance requirements for components. The corresponding components must not only meet the requirements in terms of mechanical properties such as strength, stiffness, and rigidity, but also meet additional functional requirements such as thermal, electromagnetic radiation, and other functional requirements to achieve multifunctionality of the same component. Therefore, heterogeneous material additive manufacturing technology has become a major way to achieve structural innovation and functional integration.

[0003] However, the interfacial bonding performance of heterogeneous materials has become one of the problems that restrict the manufacture and use of heterogeneous material structural parts. For example, when two metal materials, material A and material B, are fused, a large amount of brittle metal compounds are easily formed at the interface, and the interface is prone to cracking, making it impossible to achieve a tight connection. The commonly used method is to introduce a third material C as an intermediate layer at the interface of two difficult-to-melt materials. The transition layer materials are A to C, and then from C to B. For more extreme cases, it may be necessary to introduce a fourth material D. The transition layers are A to C, C to D, and then D to A. However, this method requires the introduction of a third material as a transition material, which increases the difficulty of process control and the complexity of implementation.

[0004] Therefore, it is urgent to design a selective laser melting additive manufacturing method for transition fusion of heterogeneous materials to solve the above problems. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: In order to solve the problem of difficult interface fusion of two incompatible heterogeneous materials, this application proposes a process method based on gradient mixing transition of two materials. By mixing two different single materials in different proportions as a gradient transition section, a gradual transition of the two materials is achieved, and ultimately the purpose of enhancing the interface bonding performance of the two materials is achieved.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a selective laser melting additive manufacturing method for transition fusion of heterogeneous materials interface, comprising the following steps:

[0007] S1: Inputting a 3D part model to be printed and the material composition of the 3D part into a selective laser melting additive manufacturing device, slicing the 3D part model vertically to form N layers of slices, and generating trajectory data and material composition for each layer of the 3D model slice;

[0008] S2: setting the laser parameters of the laser printing mechanism, the powder discharging parameters of the powder discharging mechanism, and the paving working parameters of the paving mechanism in the corresponding selective laser melting additive manufacturing device according to the material composition of each layer of the slice, wherein the powder discharging mechanism includes a powder supply component for supplying two different single powders, a powder mixing component for mixing the two single powders to form a mixed powder, and a powder dropping component for controlling the powder dropping and discharging of one of the two different single powders and the mixed powder; the three-dimensional part is divided into a bottom section, a transition section, and a top section from bottom to top in the vertical direction, and the mixed powder is used as a transition section for transition fusion of the laser melting additive of the three-dimensional part, the bottom section includes k layers of the slices, the transition section includes m layers of the slices, and the top section includes q layers of the slices, where k+m+q=N;

[0009] S3: The selective laser melting additive manufacturing device uses one of the two single powders to laser print the k-layer slices of the bottom segment to form the bottom segment of the three-dimensional part;

[0010] S4: The selective laser melting additive manufacturing device uses the mixed powder to laser print the m layers of slices of the transition section to form the transition section of the three-dimensional part. The ratio of the two single powders in the mixed powder to the corresponding mixed powder includes a gradually changing mixing ratio or an equal mixing ratio, wherein the gradually changing mixing ratio is that, in the mixed powder forming each layer of the slices in the transition section, the proportion of the single powder that is the same as the single powder required for the bottom section in the corresponding mixed powder decreases layer by layer from bottom to top, and the equal mixing ratio is that, in the mixed powder forming each layer of the slices in the transition section, the proportion of the two single powders in the corresponding mixed powder is the same;

[0011] S5: The selective laser melting additive manufacturing device uses the other of the two single powders to laser print the q layers of slices of the top segment to form the top segment of the three-dimensional part.

[0012] As a preferred technical solution of the present invention, S1 specifically includes the following steps:

[0013] S1.1: Input the 3D part model to be printed and the material components forming the 3D part into the selective laser melting additive manufacturing device;

[0014] S1.2: Slicing the three-dimensional part model along the vertical direction to form N slices;

[0015] S1.3: Generate trajectory data and material composition of each slice.

[0016] As a preferred technical solution of the present invention, the powder supply component includes a powder box A for supplying one single powder and a powder box B for supplying another single powder. Powder supply quantity control parts are provided at the outlet positions of the powder box A and the powder box B, and the powder supply inlets of the two powder supply quantity control parts are respectively connected to the powder outlets of the powder box A and the powder box B.

[0017] As an optimal technical solution of the present invention, the powder mixing component includes a powder mixing seat, a powder mixing bin, a bin body driving unit and a powder mixing and stirring unit, the powder mixing seat is provided with a powder mixing chamber, and the upper part of the powder mixing chamber is respectively connected to the two powder supply outlets of the powder supply control unit, the powder mixing bin is located in the powder mixing chamber, the powder mixing bin is provided with an opening, and a powder mixing bin partition is provided on the outer side of the powder mixing bin facing away from the opening. The bin body driving unit is provided on the powder mixing seat and the output end extends into the powder mixing chamber and is driven and connected to the powder mixing bin, for driving the powder mixing bin to flip the powder mixing bin so that the opening is switched between upward and downward, the powder mixing and stirring unit includes a stirring structure and a stirring driving structure, the stirring structure is located in the powder mixing bin, and the stirring driving structure is provided on the powder mixing seat and the output end extends into the powder mixing bin and is driven and connected to the stirring structure for driving the stirring structure to stir.

[0018] As a preferred technical solution of the present invention, the powder dropping assembly includes a powder dropping nozzle, the lower portion of the powder mixing chamber is communicated with the powder dropping nozzle in the powder dropping assembly, and the powder dropping nozzle includes a powder A channel, a powder B channel, and a mixed powder channel;

[0019] When mixed powder needs to be supplied, the silo driving unit causes the opening to face upward, and the powder supply outlets of the two powder supply control units are both connected to the mixed powder silo to supply the single powder in powder box A and the single powder in powder box B. Then, the stirring driving unit drives the stirring structure to stir the powder in the mixed powder silo. After the stirring is completed, the silo driving unit causes the opening to face downward and connect to the mixed powder channel to supply the mixed powder.

[0020] When a single powder is supplied from powder box A and a single powder is supplied from powder box B respectively, the bin driving part makes the opening face downward and the powder mixing bin partition face upward. At this time, the powder mixing bin partition is located between the two powder supply outlets of the powder supply quantity control parts, and the powder supply outlet of the powder supply quantity control part corresponding to the powder box A is connected to the A powder channel, and the powder supply outlet of the powder supply quantity control part corresponding to the powder box B is connected to the B powder channel.

[0021] As a preferred technical solution of the present invention, in the S4 step, when the proportional relationship is a gradually changing mixing ratio, in the mixed powder forming each layer of the slice in the transition section, the proportion of the single powder that is the same as the single powder required for the bottom section in the corresponding mixed powder decreases layer by layer from bottom to top. In the mixed powder required for the bottom slice, the proportion of the single powder that is the same as the single powder required for the bottom section in the corresponding mixed powder is 90%-70%, and in the mixed powder required for the top slice, the proportion of the single powder that is the same as the single powder required for the bottom section in the corresponding mixed powder is 10%-30%.

[0022] As a preferred technical solution of the present invention, in the S4 step, when the proportional relationship is a gradually changing mixing ratio, in the mixed powder forming each layer of the slice in the transition section, the proportion of the single powder that is the same as the single powder required for the bottom section in the corresponding mixed powder decreases layer by layer from bottom to top. In the mixed powder required for the bottom slice, the proportion of the single powder that is the same as the single powder required for the bottom section in the corresponding mixed powder is 75%, and in the mixed powder required for the top slice, the proportion of the single powder that is the same as the single powder required for the bottom section in the corresponding mixed powder is 25%.

[0023] As a preferred technical solution of the present invention, in the step S4, when the proportion relationship is an equal mixing ratio, in the mixed powder forming each layer of the slices in the transition section, the proportions of the two single powders in the corresponding mixed powder are both 1:1.

[0024] As a preferred technical solution of the present invention, the proportions in step S4 are the weight proportions of the two single powders in the corresponding mixed powders.

[0025] As a preferred technical solution of the present invention, the proportions in step S4 are the volume proportions of the two single powders in the corresponding mixed powders.

[0026] The beneficial effects of the present invention are embodied in:

[0027] 1. Use the original two materials in a specific ratio to transition between heterogeneous materials. This method does not introduce a third material, reducing the process flow of heterogeneous material interface bonding.

[0028] 2. By setting up a powder supply component, a powder mixing component and a powder dropping component, it is possible to achieve separate powder dropping or mixed powder dropping of two different single materials.

[0029] 3. A transition section is set up to transition two different materials in a manner of component gradient change to improve the interface bonding strength of heterogeneous materials.

[0030] 4. By setting different components and process parameters for the slice layer, it can be compatible with the interface transition and bonding of more heterogeneous materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0032] Figure 2 It is a schematic flow diagram of the present invention;

[0033] Figure 3 It is a schematic diagram of the overall structure of the powder discharging mechanism of the present invention;

[0034] Figure 4 It is a schematic structural diagram of the powder supply assembly and other parts of the present invention;

[0035] Figure 5 It is a front view schematic diagram of the powder supply assembly and other parts of the present invention;

[0036] Figure 6 It is a side cross-sectional schematic diagram of the powder supply assembly and other parts of the present invention;

[0037] Figure 7 It is a cross-sectional schematic diagram of the seat body and other parts of the present invention;

[0038] Figure 8 is a schematic diagram of a powder mixing assembly of the present invention;

[0039] Figure 9 It is a cross-sectional schematic diagram of the powder mixing component and other parts of the present invention;

[0040] Figure 10 Schematic diagram of the powder mixing bin of the present invention;

[0041] Figure 11 It is a cross-sectional schematic diagram of the powder mixing bin of the present invention;

[0042] Figure 12 It is a schematic diagram of the stirring structure of the present invention;

[0043] Figure 13 It is a front view schematic diagram of the stirring structure of the present invention;

[0044] Figure 14 Schematic diagram of the powder dropping assembly of the present invention;

[0045] Figure 15 It is a cross-sectional schematic diagram of the powder mixing seat and other parts of the present invention;

[0046] Figure 16 It is a cross-sectional schematic diagram of the powder mixing seat and the powder dropping nozzle of the present invention;

[0047] Figure 17This is a diagram showing the proportions of the material components in the bottom section, transition section, and top section when the present invention adopts a stepwise change in the mixing ratio;

[0048] Figure 18 This is a diagram showing the proportions of the material components in the bottom section, transition section, and top section when the present invention adopts an equal mixing ratio.

[0049] In the figure: 100, powder supply assembly; 200, powder mixing assembly; 300, powder dropping assembly; 400, scraper; 500, material transport vehicle; 600, laser printing mechanism; 700, overflow bin; 800, substrate; 1, powder box A; 2, powder box B; 3, seat; 31, seat cavity; 4, powder supply servo motor; 5, powder supply roller; 6, powder mixing seat; 61, powder mixing cavity; 7, powder mixing bin; 71, opening; 72, powder mixing Bin partition; 8. Pneumatic swing table; 9. Stirring servo motor; 10. Stirring shaft; 11. Stirring fan blade; 12. Powder drop nozzle; 121. Powder A channel; 122. Powder B channel; 123. Mixed powder channel; 124. Mixed powder channel partition; 13. Powder drop mounting seat; 14. Powder A inlet; 15. Powder B inlet; 16. Powder A observation window; 17. Powder B observation window; 18. Powder A level meter; 19. Powder B level meter. DETAILED DESCRIPTION

[0050] The present invention will now be described in further detail with reference to the accompanying drawings.

[0051] Combined with attachment Figure 1-16 As shown, a selective laser melting additive manufacturing method for transition fusion of heterogeneous materials includes a powder supply component 100, a powder mixing component 200, a powder dropping component 300, a scraper 400, a material transport vehicle 500, a laser printing mechanism 600, an overflow bin 700, a base plate 800, an A powder box 1, a B powder box 2, a seat 3, a seat cavity 31, a powder supply servo motor 4, a powder supply roller 5, a powder mixing seat 6, a powder mixing cavity 61, a powder mixing bin 7, an opening 71, a powder mixing bin partition 72, a pneumatic swing table 8, a stirring servo motor 9, a stirring shaft 10, a stirring fan blade 11, a powder dropping nozzle 12, an A powder channel 121, a B powder channel 122, a mixed powder channel 123, a mixed powder channel partition 124, a powder dropping mounting seat 13, an A powder inlet 14, a B powder inlet 15, an A powder observation window 16, a B powder observation window 17, an A powder level meter 18, and a B powder level meter 19.

[0052] Combined with attachment Figure 1-18 As shown, a selective laser melting additive manufacturing method for transitional fusion of heterogeneous materials at the interface comprises the following steps:

[0053] S1: Inputting a 3D part model to be printed and the material composition of the 3D part into a selective laser melting additive manufacturing device, slicing the 3D part model vertically to form N layers of slices, and generating trajectory data and material composition for each layer of the 3D model slice;

[0054] Specifically:

[0055] S1.1: Input the 3D part model to be printed and the material components forming the 3D part into the selective laser melting additive manufacturing device;

[0056] Preferably, the selective laser melting additive manufacturing device includes a processing center for operating and processing data, which can be performed by computer processing;

[0057] S1.2: Slicing the three-dimensional part model along the vertical direction to form N slices;

[0058] Preferably, when generating slices, existing commercial software or open source software can generate slice data, and each slice layer includes a contour track and a filling track of each layer;

[0059] S1.3: generating trajectory data and material composition of each slice;

[0060] S2: setting the laser parameters of the laser printing mechanism 600, the powder discharging parameters of the powder discharging mechanism, and the paving working parameters of the paving mechanism in the corresponding selective laser melting additive manufacturing device according to the material composition of each layer of the slice, wherein the powder discharging mechanism includes a powder supply component 100 for supplying two different single powders, a powder mixing component 200 for mixing the two single powders to form a mixed powder, and a powder dropping component 300 for controlling the powder dropping and discharging of one of the two different single powders and the mixed powder; the three-dimensional part is divided into a bottom section, a transition section, and a top section from bottom to top in the vertical direction, and the mixed powder is used as a transition section for transition fusion of the laser melting additive of the three-dimensional part, the bottom section includes k layers of the slices, the transition section includes m layers of the slices, and the top section includes q layers of the slices, where k+m+q=N;

[0061] Specifically:

[0062] The laser parameters mainly include laser power and scanning speed;

[0063] The laser printing mechanism includes a laser emitter and a scanning galvanometer that cooperates with the laser emitter.

[0064] The paving mechanism includes an operating table, a material transport cart 500, a scraper 400 and a base plate 800 that can move up and down. The scraper 400 moves on the operating table, the material transport cart 500 is arranged on the scraper 400, and the base plate 800 is located in the operating table. Initially, the surface of the base plate 800 is flush with the plane of the operating table. When paving is performed with the help of the paving mechanism, the powder falls onto the material transport cart 500, and then the scraper 400 spreads the powder on the operating table. After paving, printing is performed with the help of the laser printing mechanism 600. After printing is completed, the height of the base plate 800 is adjusted according to the height of the printed part so that the horizontal plane where the top of the part is located is flush with the flat plane of the operating table, and then the scraper 400 is used to perform the subsequent paving work of the part falling onto the material transport cart 500. An overflow bin 700 connected to the operating space of the operating table is provided on the side of the operating table for collecting excess powder after paving by the scraper 400;

[0065] The tiling working parameters include the operating parameters of the scraper 400 in coordinating with the powder dropping and the actual printing, and the operating parameters of the substrate 800 in coordinating with the actual printing process.

[0066] The powder supply assembly 100 includes a powder box A 1 for supplying a single type of powder and a powder box B 2 for supplying another single type of powder. Powder supply quantity control units are provided at the outlets of the powder box A 1 and the powder box B 2. The powder supply inlets of the two powder supply quantity control units are respectively connected to the powder outlets of the powder box A 1 and the powder box B 2.

[0067] The powder mixing assembly 200 includes a powder mixing seat 6, a powder mixing bin 7, a bin body driving unit and a powder mixing and stirring unit. A powder mixing chamber 61 is provided in the powder mixing seat 6, and the upper portion of the powder mixing chamber 61 is communicated with two powder supply outlets of the powder supply control unit respectively. The powder mixing bin 7 is located in the powder mixing chamber 61, an opening 71 is provided on the powder mixing bin 7, and a powder mixing bin partition 72 is provided on the outer side of the powder mixing bin 7 facing away from the opening 71. The bin body driving unit is provided on the powder mixing seat 6, and the output end extends into the powder mixing chamber 61 and is driven and connected to the powder mixing bin 7, so as to drive the powder mixing bin 7 to flip so that the opening 71 is switched between upward and downward. The powder mixing and stirring unit includes a stirring structure and a stirring driving structure, wherein the stirring structure is located in the powder mixing bin 7, and the stirring driving structure is provided on the powder mixing seat 6, and the output end extends into the powder mixing bin 7 and is driven and connected to the stirring structure for driving the stirring structure to stir;

[0068] The powder dropping assembly 300 includes a powder dropping nozzle 12. The lower portion of the powder mixing chamber 61 is connected to the powder dropping nozzle 12 in the powder dropping assembly. The powder dropping nozzle 12 includes a powder A channel 121, a powder B channel 122, and a mixed powder channel 123.

[0069] The laser printing mechanism 600, the powder discharging mechanism and the paving mechanism are assembled together through connectors;

[0070] For example, the bottom section uses a single powder in powder box A 1 and the top section uses a single powder in powder box B 2;

[0071] S3: the selective laser melting additive manufacturing device uses the single powder in the powder box A 1 to laser print the k-layer slices of the bottom section to form the bottom section of the three-dimensional part;

[0072] Specifically:

[0073] S3.1: The powder discharging mechanism discharges the single powder in powder box A 1 according to the powder discharging parameters of the first layer of slices from bottom to top;

[0074] S3.2: The spreading mechanism spreads the single powder after the powder falls and is discharged;

[0075] S3.3: The laser printing mechanism 600 performs laser printing on the flattened single powder according to the laser parameters of the first layer of slices from bottom to top, so as to form the first layer of slices from bottom to top of the three-dimensional part;

[0076] S3.4: Repeat S3.1-S3.3 to perform laser printing on the second slice layer on the first slice layer from bottom to top, then repeat S3.1-S3.3 to perform laser printing on the third slice layer, the fourth slice layer, and so on the k-1 slice layer from bottom to top, until laser printing of all k slice layers of the bottom section of the three-dimensional part is completed;

[0077] During the above process, the bin driving unit makes the opening 71 face downward and the powder mixing bin partition 72 face upward. At this time, the powder mixing bin partition 72 is located between the two powder supply outlets of the powder supply quantity control unit. The powder supply outlet of the powder supply quantity control unit corresponding to the A powder box 1 is connected to the A powder channel 121, and the powder supply outlet of the powder supply quantity control unit corresponding to the B powder box 2 is connected to the B powder channel 122.

[0078] S4: The selective laser melting additive manufacturing device uses the mixed powder to laser print the m layers of slices of the transition section to form the transition section of the three-dimensional part. The ratio of the two single powders in the mixed powder to the corresponding mixed powder includes a gradually changing mixing ratio or an equal mixing ratio, wherein the gradually changing mixing ratio is that, in the mixed powder forming each layer of the slices in the transition section, the proportion of the single powder that is the same as the single powder required for the bottom section in the corresponding mixed powder decreases layer by layer from bottom to top, and the equal mixing ratio is that, in the mixed powder forming each layer of the slices in the transition section, the proportion of the two single powders in the corresponding mixed powder is the same;

[0079] Specifically:

[0080] S4.1: The powder discharging mechanism discharges the mixed powder according to the powder discharging parameters of the slices of the k+1th layer from bottom to top;

[0081] S4.2: The spreading mechanism spreads the mixed powder after the powder falls and is discharged;

[0082] S4.3: The laser printing mechanism 600 performs laser printing on the tiled mixed powder according to the laser parameters of the slice of the k+1 layer from bottom to top, so as to form the slice of the k+1 layer from bottom to top of the three-dimensional part;

[0083] S4.4: Repeat S4.1-S4.3 to laser print the slice of the k+2th layer on the k+1th layer from bottom to top, then repeat S4.1-S4.3 to laser print the slice of the k+2th layer, the k+3th layer, ... the k+(m-1)th layer, ... the k+3th layer, ... the k+4th layer, ... the k+mth layer, until laser printing of all m layers of slices in the transition section of the three-dimensional part model is completed;

[0084] During the above process, the silo driving unit makes the opening 71 face upward, and the powder supply outlets of the two powder supply control units are both connected to the powder mixing silo 7 to supply the single powder in the powder box A 1 and the single powder in the powder box B 2. Then, the stirring driving unit drives the stirring structure to stir the powder in the powder mixing silo 7. After the stirring is completed, the silo driving unit makes the opening 71 face downward to communicate with the mixed powder channel 123 to supply the mixed powder.

[0085] When the proportion relationship is a gradually changing mixing ratio, in the mixed powder forming each layer of the slice in the transition section, the proportion of the single powder in the A powder box 1 in the corresponding mixed powder decreases layer by layer from bottom to top. In the mixed powder required for the slice at the bottom, the proportion of the single powder in the A powder box 1 in the corresponding mixed powder is 90%-70%, and in the mixed powder required for the slice at the top, the proportion of the single powder in the A powder box 1 in the corresponding mixed powder is 10%-30% (the specific material component proportions are as follows: Figure 17 As shown), the proportion is the weight proportion of the two single powders in the corresponding mixed powder, or the proportion is the volume proportion of the two single powders in the corresponding mixed powder, and the gradual change of the proportion can be linear or nonlinear;

[0086] Specifically:

[0087] When the proportion relationship is a gradual change in the mixing ratio, in the mixed powder forming each layer of the slice in the transition section, the proportion of the single powder in the A powder box 1 in the corresponding mixed powder decreases layer by layer from bottom to top. In the required mixed powder in the bottom slice, the single powder in the A powder box 1 accounts for 90% of the corresponding mixed powder, and in the required mixed powder in the top slice, the single powder in the A powder box 1 accounts for 10% of the corresponding mixed powder. The proportions are the weight proportions of the two single powders in the corresponding mixed powders, or the proportions are the volume proportions of the two single powders in the corresponding mixed powders. The gradual change of the proportions It can be linear or nonlinear. When the gradual change of the proportion is linear, preferably, from bottom to top, according to the specific number of slices in the transition section, the proportion of the single powder in the powder box A 1 in the corresponding mixed powder in each layer of the slice in the transition section can be 90%, 85%, ..., 10%, or 90%, 80%, ..., 10%, etc. When the gradual change of the proportion is nonlinear, the proportion of the single powder in the powder box A 1 in the corresponding mixed powder in each layer of the slice in the transition section can be 90%, 87%, 82%, ..., 16%, 14%, 10%, or 90%, 84%, 81%, ..., 14%, 11%, 10%, etc.;

[0088] Or, in the mixed powder forming each layer of the slice in the transition section, the proportion of the single powder in the A powder box 1 in the corresponding mixed powder decreases layer by layer from bottom to top, and the single powder in the A powder box 1 in the required mixed powder in the bottom slice accounts for 80% of the corresponding mixed powder, and the single powder in the A powder box 1 in the required mixed powder in the top slice accounts for 20% of the corresponding mixed powder. The proportions are the weight proportions of the two single powders in the corresponding mixed powders, or the proportions are the volume proportions of the two single powders in the corresponding mixed powders, and the proportions change gradually. It may be linear or nonlinear. Preferably, from bottom to top, according to the specific number of slices in the transition section, the proportion of the single powder in the powder box A 1 in the corresponding mixed powder in each slice in the transition section may be 80%, 75%, ..., 20%, or 80%, 70%, ..., 20%, etc. When the gradual change of the proportion is nonlinear, the proportion of the single powder in the powder box A 1 in the corresponding mixed powder in each slice in the transition section may be 80%, 77%, 72%, ..., 26%, 24%, 20%, or 80%, 74%, 71%, ..., 24%, 21%, 20%, etc.;

[0089] Or, in the mixed powder forming each layer of the slice in the transition section, the proportion of the single powder in the A powder box 1 in the corresponding mixed powder decreases layer by layer from bottom to top, and the single powder in the A powder box 1 in the required mixed powder in the bottom slice accounts for 75% of the corresponding mixed powder, and the single powder in the A powder box 1 in the required mixed powder in the top slice accounts for 25% of the corresponding mixed powder. The proportions are the weight proportions of the two single powders in the corresponding mixed powders, or the proportions are the volume proportions of the two single powders in the corresponding mixed powders, and the proportions change gradually. It may be linear or nonlinear. Preferably, from bottom to top, according to the specific number of slices in the transition section, the proportion of the single powder in the powder box A 1 in the corresponding mixed powder in each slice in the transition section may be 75%, 70%, ..., 25%, or 75%, 65%, ..., 25%, etc. When the gradual change of the proportion is nonlinear, the proportion of the single powder in the powder box A 1 in the corresponding mixed powder in each slice in the transition section may be 75%, 72%, 70%, ..., 30%, 27%, 25%, or 75%, 74%, 71%, ..., 29%, 26%, 25%, etc.;

[0090] Or, in the mixed powder forming each layer of the slice in the transition section, the proportion of the single powder in the A powder box 1 in the corresponding mixed powder decreases layer by layer from bottom to top, and the single powder in the A powder box 1 in the required mixed powder in the bottom slice accounts for 70% of the corresponding mixed powder, and the single powder in the A powder box 1 in the required mixed powder in the top slice accounts for 30% of the corresponding mixed powder. The proportions are the weight proportions of the two single powders in the corresponding mixed powders, or the proportions are the volume proportions of the two single powders in the corresponding mixed powders, and the proportions change gradually. It may be linear or nonlinear. Preferably, from bottom to top, according to the specific number of slices in the transition section, the proportion of the single powder in the powder box A 1 in the corresponding mixed powder in each slice layer in the transition section may be 70%, 65%, ..., 30%, or 70%, 60%, ..., 30%, etc. When the gradual change of the proportion is nonlinear, the proportion of the single powder in the powder box A 1 in the corresponding mixed powder in each slice layer in the transition section may be 70%, 67%, 62%, ..., 36%, 34%, 30%, or 70%, 64%, 61%, ..., 34%, 31%, 30%, etc.;

[0091] When the ratio is an equal mixing ratio, in the mixed powder forming each layer of the slice in the transition section, the two single powders account for the same proportion in the corresponding mixed powder, that is, the single powder in powder box A 1 accounts for 50% of the corresponding mixed powder, and the single powder in powder box B 2 accounts for 50% of the corresponding mixed powder (the specific material component proportions are as follows: Figure 18 As shown), the proportions are the weight proportions of the two single powders in the corresponding mixed powders, or the proportions are the volume proportions of the two single powders in the corresponding mixed powders;

[0092] S5: the selective laser melting additive manufacturing device uses the single powder in the B powder box 2 to laser print the q layers of the slices of the top segment to form the top segment of the three-dimensional part;

[0093] Specifically:

[0094] S5.1: The powder discharging mechanism discharges the single powder in the powder box B 2 according to the powder discharging parameters of the slice of the k+m+1 layer from bottom to top;

[0095] S5.2: The spreading mechanism spreads the single powder after the powder falls and is discharged;

[0096] S5.3: The laser printing mechanism 600 performs laser printing on the flattened single powder according to the laser parameters of the slice of the k+m+1 layer from bottom to top, to form the slice of the k+m+1 layer from bottom to top of the three-dimensional part;

[0097] S5.4: Repeat S5.1-S5.3 to perform laser printing of the slice of the k+m+2th layer on the k+m+1th layer from bottom to top, and then repeat S5.1-S5.3 to perform laser printing of the slice of the k+m+3th layer, the slice of the k+m+4th layer... the slice of the k+m+qth layer on the k+m+2th layer, the slice of the k+m+3th layer... the slice of the k+m+(q-1)th layer from bottom to top, until the laser printing of all the slices of the q layers of the top segment of the three-dimensional part model is completed.

[0098] Combined with attachment Figure 1-16 As shown, in the above steps, further:

[0099] The powder supply quantity control unit includes a seat body 3, a powder supply servo motor 4 and a powder supply roller shaft 5. The seat body 3 corresponding to the A powder box 1 is installed at the powder outlet position of the A powder box 1, and the seat body 3 corresponding to the B powder box 2 is installed at the powder outlet position of the B powder box 2. A seat body cavity 31 is opened in the seat body 3, and the powder supply inlet of the seat body cavity 31 corresponding to the A powder box 1 is communicated with the powder outlet of the A powder box 1, and the powder supply inlet of the seat body cavity 31 corresponding to the B powder box 2 is communicated with the powder outlet of the B powder box 2. The powder supply servo motor 4 is installed on the corresponding seat body 3, and the powder supply roller shaft 5 is located in the seat body cavity 31. The output end of the powder supply servo motor 4 extends into the corresponding seat body cavity 31 and is connected to the powder supply roller shaft 5. A number of splines are evenly opened on the powder supply roller shaft 5;

[0100] The powder mixing seat 6 is installed at the powder supply outlet of the seat cavity 31 corresponding to the powder box A 1 and the seat cavity 31 corresponding to the powder box B 2. The upper part of the powder mixing cavity 61 is connected to the powder supply outlet of the seat cavity 31 corresponding to the powder box A 1 and the powder supply outlet of the seat cavity 31 corresponding to the powder box B 2 respectively.

[0101] The bin driving part includes a pneumatic swing table 8, which is arranged on the powder mixing seat 6 and has an output end extending into the powder mixing chamber 61 and drivingly connected to the powder mixing bin 7;

[0102] The stirring drive structure includes a stirring servo motor 9, which is arranged on the powder mixing seat 6;

[0103] The stirring structure includes a stirring shaft 10 and stirring blades 11. The stirring blades 11 are arranged on the periphery of the stirring shaft 10. The stirring shaft 10 is located in the powder mixing bin 7. The output end of the stirring servo motor 9 extends into the powder mixing bin 7 and is connected to the stirring shaft 10.

[0104] The A powder box 1 is provided with an A powder inlet 14, and the B powder box 2 is provided with a B powder inlet 15;

[0105] The A powder box 1 is provided with an A powder observation window 16, and the B powder box 2 is provided with a B powder observation window 17;

[0106] The A powder box 1 is provided with an A powder level meter 18;

[0107] The B powder box 2 is provided with a B powder level meter 19 .

[0108] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions in the specification are only preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention as claimed. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A selective laser melting additive manufacturing method for transitional fusion of heterogeneous materials interface, characterized in that: The steps include: S1: inputting a 3D part model to be printed and a material component forming the 3D part into a selective laser melting additive manufacturing device, slicing the 3D part model in a vertical direction to form N layers of slices, and generating trajectory data and material components of each layer of slices of the 3D model; S2: according to the material composition of each layer of the slice, the laser parameters of the laser printing mechanism (600), the powder discharging parameters of the powder discharging mechanism and the paving working parameters of the paving mechanism in the corresponding selective laser melting additive manufacturing device are set, wherein the powder discharging mechanism comprises a powder supply component (100) for supplying two different single powders, a powder mixing component (200) for mixing the two single powders to form a mixed powder, and a powder dropping component (300) for controlling the powder dropping and discharging of one of the two different single powders and the mixed powder; the three-dimensional part is divided into a bottom section, a transition section and a top section from bottom to top in the vertical direction, the mixed powder is used as a transition section for transition fusion of laser melting additive of the three-dimensional part, the bottom section comprises k layers of the slice, the transition section comprises m layers of the slice, and the top section comprises q layers of the slice, k+m+q=N; S3: the selective laser melting additive manufacturing device uses one of the two single powders to laser print the k-layer slices of the bottom segment to form the bottom segment of the three-dimensional part; S4: The selective laser melting additive manufacturing device uses the mixed powder to laser print the m layers of slices of the transition section to form the transition section of the three-dimensional part. The ratio of the two single powders in the mixed powder to the corresponding mixed powder includes a step-by-step changing mixing ratio or an equal mixing ratio, wherein the step-by-step changing mixing ratio means that, in the mixed powder for forming each layer of the slices in the transition section, the proportion of the single powder that is the same as the single powder required for the bottom section in the corresponding mixed powder decreases layer by layer from bottom to top, and the equal mixing ratio means that, in the mixed powder for forming each layer of the slices in the transition section, the proportion of the two single powders in the corresponding mixed powder is the same; S5: The selective laser melting additive manufacturing device uses the other of the two single powders to laser print the q layers of the slices of the top segment to form the top segment of the three-dimensional part.

2. The selective laser melting additive manufacturing method for transitional fusion of heterogeneous materials according to claim 1, characterized in that: The S1 specifically includes the following steps: S1.1: Input the 3D part model to be printed and the material components forming the 3D part into the selective laser melting additive manufacturing device; S1.2: Slicing the three-dimensional part model along the vertical direction to form N layers of slices; S1.3: Generate trajectory data and material composition of each layer of the slice.

3. The selective laser melting additive manufacturing method for transitional fusion of heterogeneous materials according to claim 1, characterized in that: The powder supply assembly (100) comprises an A powder box (1) for supplying one single powder and a B powder box (2) for supplying another single powder. Powder supply quantity control units are provided at the outlets of the A powder box (1) and the B powder box (2). The powder supply inlets of the two powder supply quantity control units are respectively connected to the powder outlets of the A powder box (1) and the B powder box (2).

4. The selective laser melting additive manufacturing method for transitional fusion of heterogeneous materials according to claim 3, characterized in that: The powder mixing assembly (200) comprises a powder mixing seat (6), a powder mixing bin (7), a bin driving unit and a powder mixing stirring unit. A powder mixing chamber (61) is provided in the powder mixing seat (6), and the upper part of the powder mixing chamber (61) is respectively connected to two powder supply outlets of a powder supply quantity control unit. The powder mixing bin (7) is located in the powder mixing chamber (61). An opening (71) is provided on the powder mixing bin (7). A powder mixing bin partition (72) is provided on the outer side of the powder mixing bin (7) facing away from the opening (71). The bin driving unit The powder mixing portion (6) is arranged on the powder mixing seat (6) and the output end thereof extends into the powder mixing chamber (61) and is drivingly connected to the powder mixing bin (7) for driving the powder mixing bin (7) to flip so that the opening (71) switches between facing upward and facing downward. The powder mixing and stirring portion comprises a stirring structure and a stirring driving structure. The stirring structure is located in the powder mixing bin (7). The stirring driving structure is arranged on the powder mixing seat (6) and the output end thereof extends into the powder mixing bin (7) and is drivingly connected to the stirring structure for driving the stirring structure to stir.

5. The selective laser melting additive manufacturing method for transitional fusion of heterogeneous materials interface according to claim 4, characterized in that: The powder dropping component (300) comprises a powder dropping nozzle (12); the lower part of the powder mixing chamber (61) is in communication with the powder dropping nozzle (12) in the powder dropping component; the powder dropping nozzle (12) comprises an A powder channel (121), a B powder channel (122) and a mixed powder channel (123); When mixed powder needs to be supplied, the bin driving unit makes the opening (71) face upward, and the powder supply outlets of the two powder supply quantity control units are both connected to the mixed powder bin (7) to supply the single powder in the A powder box (1) and the single powder in the B powder box (2). Then, the stirring driving unit drives the stirring structure to stir the powder in the mixed powder bin (7). After the stirring is completed, the bin driving unit makes the opening (71) face downward and connect to the mixed powder channel (123) to supply the mixed powder. When a single powder is supplied from the A powder box (1) and a single powder is supplied from the B powder box (2) respectively, the bin driving unit makes the opening (71) face downward and the powder mixing bin partition (72) face upward. At this time, the powder mixing bin partition (72) is located between the powder supply outlets of the two powder supply quantity control units. The powder supply outlet of the powder supply quantity control unit corresponding to the A powder box (1) is connected to the A powder channel (121), and the powder supply outlet of the powder supply quantity control unit corresponding to the B powder box (2) is connected to the B powder channel (122).

6. The selective laser melting additive manufacturing method for transitional fusion of heterogeneous materials according to claim 1, characterized in that: In the step S4, when the proportion relationship is a gradually changing mixing ratio, in the mixed powder forming each layer of the slices in the transition section, the proportion of the single powder identical to the single powder required for the bottom section in the corresponding mixed powder decreases layer by layer from bottom to top, and the proportion of the single powder identical to the single powder required for the bottom section in the required mixed powder in the bottom slice is 90%-70% in the corresponding mixed powder, and the proportion of the single powder identical to the single powder required for the bottom section in the required mixed powder in the top slice is 10%-30% in the corresponding mixed powder.

7. The selective laser melting additive manufacturing method for transitional fusion of heterogeneous materials interface according to claim 6, characterized in that: In the step S4, when the proportion relationship is a gradually changing mixing ratio, in the mixed powder forming each layer of the slices in the transition section, the proportion of the single powder identical to the single powder required for the bottom section in the corresponding mixed powder decreases layer by layer from bottom to top, and the proportion of the single powder identical to the single powder required for the bottom section in the required mixed powder in the bottom slice is 75%; the proportion of the single powder identical to the single powder required for the bottom section in the required mixed powder in the top slice is 25%.

8. The selective laser melting additive manufacturing method for transitional fusion of heterogeneous materials interface according to claim 1, characterized in that: In the step S4, when the ratio is an equal mixing ratio, in the mixed powder for forming each layer of the slices in the transition section, the proportions of the two single powders in the corresponding mixed powder are both 1:

1.

9. The selective laser melting additive manufacturing method for transitional fusion of heterogeneous materials interface according to claim 1, characterized in that: The proportions in step S4 are weight proportions of the two single powders in the corresponding mixed powders.

10. The selective laser melting additive manufacturing method for transitional fusion of heterogeneous materials interface according to claim 1, characterized in that: The proportions in step S4 are the volume proportions of the two single powders in the corresponding mixed powders.

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