A kind of orthopedic medical 3D printing zinc-based spherical powder and preparation method

Abstract

The present invention provides a zinc-based spherical powder for orthopedic 3D printing and a preparation method, belonging to the field of metal powder materials and preparation technology. The method comprises: preparing a zinc-based metal melt that meets composition requirements; directing the zinc-based metal melt to the center of a high-speed rotating disk, accelerating the rotation, splitting, sphering, cooling, and solidifying to obtain a zinc-based spherical powder; and screening the zinc-based spherical powder to obtain the zinc-based spherical powder. By selecting a zinc-based metal and combining it with an improved rotating disk, high-quality zinc-based spherical powder for orthopedic 3D printing is prepared. The hollow powder rate of the prepared 3D printing zinc-based spherical powder is reduced to less than 1%, the powder has high sphericity, the difference between the powder particle size D90 and D10 is less than 10µm, and the powder utilization rate can reach over 90%.

Description

Technical Field

[0001] The present invention relates to the field of metal powder materials and preparation technology, and in particular to an orthopedic medical 3D printing zinc-based spherical powder and a preparation method thereof. Background Art

[0002] Due to the variability of human skeletal structure and disease conditions, conventional orthopedic treatment methods, such as "cutting feet to fit shoes," suffer from poor surgical precision, a need for improved device compatibility, and significant surgical trauma, leading to high surgical risks. "Digital precision diagnosis and treatment" has become a major trend in orthopedic medicine development both domestically and internationally. 3D printing, a key technology leading the new wave of technological and industrial transformation, enables digital precision customization of orthopedic medical devices, providing an excellent technical approach for digital precision diagnosis and treatment in orthopedics.

[0003] However, my country's orthopedic 3D printing technology still has the problem of insufficient high-quality medical powder raw materials. High-quality medical raw material powder relies on imports. In order to solve the above problems, in the prior art, the Chinese invention patent application with the application publication number CN118218580A discloses a spherical zinc-based metal powder material and its preparation method and application. By adopting a rotating disk centrifugal atomization process, the low sphericity of zinc-based metal powder and the generation of hollow powder caused by vacuum gas atomization are solved, and high-quality spherical zinc-based metal powder materials are prepared. However, this technical solution still has corresponding technical problems, that is, this solution only reduces the probability of hollow powder generation, and the degree of reduction is limited. The concentration of powder particle size arrangement is low, the proportion of non-spherical powder is still large, and the rate of unusable powder obtained by screening is high. Summary of the Invention

[0004] In response to the above-mentioned deficiencies in the prior art, the present invention provides an orthopedic medical 3D printing zinc-based spherical powder and a preparation method. By selecting a zinc-based metal and combining it with an improved rotating disk, high-quality orthopedic medical 3D printing zinc-based spherical powder is prepared. The hollow powder rate of the prepared 3D printing zinc-based spherical powder is reduced to less than 1%, the powder sphericity is high, the difference between the powder particle size D90 and D10 is less than 10µm, and the powder utilization rate can reach more than 90%.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] On the one hand, the present invention provides a method for preparing zinc-based spherical powder for orthopedic 3D printing, comprising: preparing a zinc-based metal melt that meets composition requirements; draining the zinc-based metal melt to the center of a high-speed rotating disk, and after accelerated rotation, splitting, sphericalizing, cooling, and solidifying to obtain a zinc-based spherical powder material; screening the zinc-based spherical powder material to obtain the zinc-based spherical powder; the zinc-based metal comprises, by mass percentage, Cu: 0.1%-7.0%, Mg: 0.02%-0.10%, Al: 3.5%-4.5%, Li≤0.01%, Mn≤0.02%, and the remainder is Zn; the disk comprises an impact zone, a flat flow zone, and a secondary atomization zone; the impact zone is located in the middle of the disk for receiving the zinc-based metal melt, and the impact zone has a drainage structure; the flat flow zone is annular and located on the side of the disk away from the center of the disk; the secondary atomization zone is annular and located on the side of the disk away from the center relative to the flat flow zone.

[0007] Furthermore, the temperature of the zinc-based metal melt is Tm+10° C.-Tm+50° C., wherein Tm is the liquidus temperature of the zinc-based metal melt.

[0008] Furthermore, the free vertical falling distance of the zinc-based metal melt is 30 cm-50 cm, and the flow rate of the zinc-based metal melt is 2.5 kg / min-5.0 kg / min.

[0009] Furthermore, the rotation speed of the disc is 20000 rpm-60000 rpm.

[0010] Furthermore, the drainage structure is a hemispherical protrusion provided in the impact zone, the diameter of the hemispherical protrusion is 0.5 mm-2.5 mm, and the diameter of the hemispherical protrusion gradually increases as it moves away from the center of the disc.

[0011] Furthermore, the impact zone and the advection zone are heated at a temperature of Tm+5°C to Tm+10°C, wherein Tm is the liquidus temperature of the zinc-based metal melt.

[0012] Furthermore, the secondary atomization zone is connected to the flat flow zone via a connecting portion, and the circumferential cross-sectional area of ​​the connecting portion does not exceed 1 / 10 of the circumferential area.

[0013] Furthermore, the minimum distance between the secondary atomization zone and the rotation axis forms a first distance, the maximum distance between the advection zone of the disk and the rotation axis forms a second distance, and the difference between the first distance and the second distance is related to the second distance and the rotation speed of the disk;

[0014] The difference ΔL between the first distance and the second distance satisfies the following formula:

[0015] Where L2 is the second distance, L0 is the standard distance, is the correction coefficient, the unit is mm, v is the rotation speed of the disk, and v0 is the standard speed.

[0016] Furthermore, the axis of symmetry of the radial cross-section of the secondary atomization zone intersects the rotation axis at right angles and is parallel to the surface of the flat flow zone, the axis of symmetry is located on the upper surface of the flat flow zone, and there is a gap between the two, the size of the gap is 0.01mm-0.05mm; the secondary atomization zone includes a flow-incoming portion and a flow-guiding portion, the surface of the radial cross-section of the flow-incoming portion is a first arc, the center of curvature of the first arc is set away from the center of the disk relative to the first arc, and the radius of curvature is 0.1mm-0.5mm; the flow-guiding portion includes an upper flow-guiding portion and a lower flow-guiding portion, the surface of the radial cross-section of the upper flow-guiding portion and the lower flow-guiding portion is a second arc, the center of curvature of the second arc is set close to the center of the disk relative to the second arc, and the radius of curvature of the second arc ranges from 5mm to 10mm; the angle between the tangent of the second arc and the intersection of the upper and lower surfaces of the secondary atomization zone and the plane perpendicular to the rotation axis of the disk and passing through the intersection is 100°-130°.

[0017] The present invention also provides an orthopedic medical 3D printing zinc-based spherical powder, which is prepared by the above-mentioned preparation method.

[0018] Compared with the prior art, the technical solution provided by the present invention brings the following beneficial effects: the zinc-based metal proposed in the present invention has limited components, zinc is an essential trace element for the human body, participates in protein synthesis, enzyme reaction and bone metabolism regulation, has low toxicity and a clear metabolic pathway, and the degradation products (such as ) can induce calcium and phosphorus deposition, promote bone integration, and the degradation rate is between magnesium-based (too fast) and iron-based (too slow). Zinc has insufficient mechanical strength (such as low tensile strength), and alloying (adding Cu, Ag, Li and other elements) can significantly improve performance. Cu can also increase the antibacterial properties of the prepared product, and Li, Mn, Mg and Al elements are added to refine the grain structure; secondly, the preparation process of spherical powder is highly related to the properties of the material, such as zinc-based metal powder. The zinc-based metal in this application has a Zn content of at least 85%, and the viscosity and surface free energy of the zinc melt are low, so hollow powder is easily produced during the preparation process, which is related to the properties of the material itself. Therefore, a suitable preparation process is selected for the zinc-based metal material proposed in this application to prepare high-quality orthopedic medical 3D printing zinc-based spherical powder; thirdly, in order to solve the problems in the preparation process of zinc-based spherical powder in the prior art, the specific structure of the disc is defined, and the specific structure of the disc is combined with the preparation process. It is the key to preparing high-quality zinc-based spherical powder. For example, the impact zone has a diversion structure. The diversion structure is intended to divert the metal melt that is drained in so that its circumferential flow rate is approximately the same, thereby forming a zinc-based metal melt layer with the same thickness and flow rate in the same radius area of ​​the horizontal flow zone. This step plays a decisive role in preparing spherical powder with a concentrated particle size distribution. In the rotating disk atomization powder making process, if the radial flow rate difference is large, it will lead to large differences in the particle size distribution of the prepared powder. For example, the centrifugal force on the thick zinc-based metal melt is also relatively large, and it passes through the edge of the disk faster and is torn into small droplets with larger particle sizes. The thinner zinc-based metal melt passes through the edge of the disk and is torn into droplets with smaller particle sizes, resulting in poor particle size distribution. On the other hand, for the zinc-based metal melt, it is cooled by inert gas after leaving the disk. The larger the particle size of the droplets, the easier it is to form hollow powder. This is also the reason why zinc-based metal powder is prone to hollow powder in the existing technology. Therefore, this is also the reason why the present application sets up a secondary atomization zone. The secondary atomization zone performs secondary atomization on droplets with larger particle sizes. At the same time, the secondary atomization zone is not heated. After the droplets collide with the secondary atomization zone, the droplet speed is reduced and split into smaller droplets. Combined with cooling, the droplets are prevented from being impacted by the cooling gas to form hollow powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 A schematic diagram of the disc structure provided by an embodiment of the present invention;

[0021] Figure 2 for Figure 1 A partial enlarged view of point A in the middle;

[0022] Figure 3 A cross-sectional view of a disc provided by an embodiment of the present invention;

[0023] Figure 4 for Figure 3 A partial enlarged view of point C in the middle;

[0024] Figure 5 This is the SEM image of peanut-shaped powder in the prior art;

[0025] Figure 6 The powder SEM image of the zinc-based composite powder material prepared in Example 1 of the present invention, a is the overall morphology image, b is the local enlarged image

[0026] Figure 7 This is a powder SEM image of the zinc-based composite powder material prepared in Comparative Example 1 of the present invention, where a is the first position and b is the second position.

[0027] Reference numerals: 01, impact zone; 010, diversion structure; 02, flat flow zone; 03, secondary atomization zone; 030, flow-incoming part; 031, diversion part; 04, connecting part. DETAILED DESCRIPTION

[0028] To make the objectives, technical solutions, and advantages of the present invention more apparent, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The specific implementation methods of the present invention are not limited to the specific embodiments given herein, and those skilled in the art may make similar improvements without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used are only for describing specific embodiments and do not limit the present invention.

[0030] The present invention provides a method for preparing orthopedic medical 3D printing zinc-based spherical powder, comprising:

[0031] S1. Prepare a zinc-based metal melt that meets composition requirements.

[0032] In the zinc-based metal, by mass percentage, Cu: 0.1%-7.0%, Mg: 0.02%-0.10%, Al: 3.5%-4.5%, Li≤0.01%, Mn≤0.02%, and the rest is Zn.

[0033] S2. The zinc-based metal melt is drained to the center of a high-speed rotating disk, and after rotation acceleration, the melt is split, formed into balls, cooled, and solidified to obtain a zinc-based spherical powder material.

[0034] like Figure 1 As shown, the disk has an impact zone 01, a horizontal flow zone 02 and a secondary atomization zone 03; the impact zone 01 is located in the middle of the disk, for receiving the zinc-based metal melt, and the impact zone 01 has a diversion structure; the horizontal flow zone 02 is annular, and is located on the side of the disk away from the center of the disk; the secondary atomization zone 03 is annular and is located on the side away from the center of the disk relative to the horizontal flow zone.

[0035] S3. Screening the zinc-based spherical powder material to obtain the zinc-based spherical powder.

[0036] The zinc-based metal proposed in the present invention has its components limited. Zinc is an essential trace element for the human body, involved in protein synthesis, enzyme reaction and bone metabolism regulation, with low toxicity and clear metabolic pathway. ) can induce calcium and phosphorus deposition, promote bone integration, and the degradation rate is between magnesium-based (too fast) and iron-based (too slow). Zinc has insufficient mechanical strength (such as low tensile strength), and alloying (adding Cu, Ag, Li and other elements) can significantly improve performance. Cu can also increase the antibacterial properties of the prepared product, and Li, Mn, Mg and Al elements are added to refine the grain structure; secondly, the preparation process of spherical powder is highly related to the properties of the material. For example, zinc-based metal powder, such as the zinc-based metal in this application, has a Zn content of at least 85%, and the viscosity and surface free energy of the zinc melt are low, so hollow powder is easily produced during the preparation process, which is related to the properties of the material itself. Therefore, a suitable preparation process is selected for the zinc-based metal material proposed in this application to prepare high-quality orthopedic medical 3D printing zinc-based spherical powder; thirdly, in order to solve the problems in the preparation process of zinc-based spherical powder in the prior art, the specific structure of the disc is defined, and the specific structure of the disc is combined with the preparation process. It is the key to preparing high-quality zinc-based spherical powder. For example, the impact zone has a diversion structure. The diversion structure is intended to divert the metal melt that is drained in so that its circumferential flow rate is approximately the same, thereby forming a zinc-based metal melt layer with the same thickness and flow rate in the same radius area of ​​the horizontal flow zone. This step plays a decisive role in preparing spherical powder with a concentrated particle size distribution. In the rotating disk atomization powder making process, if the radial flow rate difference is large, it will lead to large differences in the particle size distribution of the prepared powder. For example, the centrifugal force on the thick zinc-based metal melt is also relatively large, and it passes through the edge of the disk faster and is torn into small droplets with larger particle sizes. The thinner zinc-based metal melt passes through the edge of the disk and is torn into droplets with smaller particle sizes, resulting in poor particle size distribution. On the other hand, for the zinc-based metal melt, it is cooled by inert gas after leaving the disk. The larger the particle size of the droplets, the easier it is to form hollow powder. This is also the reason why zinc-based metal powder is prone to hollow powder in the existing technology. Therefore, this is also the reason why the present application sets up a secondary atomization zone. The secondary atomization zone performs secondary atomization on droplets with larger particle sizes. At the same time, the secondary atomization zone is not heated. After the droplets collide with the secondary atomization zone, the droplet speed is reduced and split into smaller droplets. Combined with cooling, the droplets are prevented from being impacted by the cooling gas to form hollow powder.

[0037] In the embodiment of the present invention, when preparing the zinc-based metal melt with the composite component requirements, it is preferred to add materials in the form of adding an intermediate alloy to reduce the burning loss of elements.

[0038] The temperature of the zinc-based metal melt is Tm+10° C. to Tm+50° C., where Tm is the liquidus temperature of the zinc-based metal melt. By limiting the temperature of the zinc-based metal melt, the viscosity of the zinc-based metal melt meets specific requirements.

[0039] Specifically, the free vertical falling distance of the zinc-based metal melt is 30cm-50cm, and the flow rate of the zinc-based metal melt is 2.5 kg / min-5.0kg / min. Since the technical solution of the present invention adopts a drainage structure, it has a certain impact on the flow of the zinc-based metal melt. If the distance between the outlet of the zinc-based metal melt and the disc is set too small, the obstruction of the drainage structure on the zinc-based metal melt is aggravated, and if the distance is set too large, the impact force of the zinc-based metal melt is large, which reduces the uniformity of the drainage structure in distributing the melt. Secondly, the flow control of the zinc-based metal melt and the distance between the outlet of the zinc-based metal melt and the disc have similar principles. If the flow rate of the zinc-based metal melt is small, the preparation efficiency is reduced, and if the flow rate is too large, part of the undistributed fluid will pass over the drainage structure, causing the drainage structure to fail.

[0040] The "free vertical fall distance" in the present invention refers to the vertical distance that the zinc-based metal melt travels after flowing out of the smelting furnace outlet under the action of gravity before impacting the center of the disk. The vertical distance is the free vertical fall distance, which is used to accelerate the fluid so that the zinc-based metal melt has a certain impact force when contacting the center of the disk.

[0041] Specifically, the rotation speed of the disc is 20,000 rpm-60,000 rpm.

[0042] Specifically, such as Figure 2 As shown, the drainage structure 010 is a hemispherical protrusion provided in the impact zone 01, and the diameter of the hemispherical protrusion is 0.5 mm -2.5 mm, and the diameter of the hemispherical protrusion gradually increases as it moves away from the center of the disk. Preferably, the diameter of the outermost radial protrusion is not less than 1 mm different from that of the innermost layer, so as to ensure that the drainage structure properly blocks the zinc-based metal melt, so as to increase the uniformity of the zinc-based metal melt in the same radial distribution in the horizontal flow zone. Preferably, the diameter of the impact zone 01 is 1.2-1.5 times the diameter of the incoming zinc-based metal melt, so as to ensure that the incoming flow of the zinc-based metal melt is within the range of the impact zone 01 and has a good diversion effect. Figure 2 , showing multiple layers of hemispherical protrusions arranged in a circle, with the center of the disc as the center of the circle, and the diameters of the hemispherical protrusions on the same radius are the same. Preferably, in the same circle layer, the gap between the two hemispherical protrusions is not less than half the diameter of the hemispherical protrusions in the circle layer and not greater than the diameter of the hemispherical protrusions in the circle layer. Through the above structural definition, combined with the distance between the outlet of the zinc-based metal melt of the present application and the disc and the flow rate of the zinc-based metal melt, it is ensured that the drainage structure is always kept in the best state. It should be made clear that the above size limitation is related to the zinc-based metal used in the embodiment of the invention, and does not belong to the material protected in this application. Its physical properties such as viscosity cannot be adapted to the disc of this application.

[0043] The disk is preferably made of graphite material, and the impact zone and the advection zone are heated at a temperature of Tm+5°C-Tm+10°C, where Tm is the liquidus temperature of the zinc-based metal melt.

[0044] like Figure 3 As shown, the secondary atomization zone 03 is connected to the advection zone 02 via a connection 04, and the circumferential cross-sectional area of ​​the connection 04 does not exceed 1 / 10 of the circumferential area. By reducing the cross-sectional area of ​​the connection 04, the heat transfer from the advection zone 02 to the secondary atomization zone 03 is reduced. On the one hand, the present invention increases the uniformity of the zinc-based metal melt on the surface of the advection zone 02 by providing a drainage structure, including the same thickness and velocity of the metal melt at the same radius. If the secondary atomization zone is not provided, due to the high temperature and low viscosity of the zinc-based metal melt, high-speed metal droplets are easily reacted with the inert gas, increasing the probability of hollow powder generation. By providing the connection, a gap is formed between the secondary atomization zone 03 and the advection zone, facilitating a certain degree of cooling of the zinc-based metal melt into small droplets at the end of the advection zone. When the small droplets interact with the secondary atomization zone, the velocity of the small droplets is reduced, and on the other hand, larger droplets are subjected to a secondary impact, atomization, and reduction of the liquid size.

[0045] like Figure 4 The minimum distance between the secondary atomization zone O3 and the rotation axis forms a first distance L1, the maximum distance between the advection zone of the disk and the rotation axis forms a second distance L2, and the difference ΔL between the first distance L1 and the second distance L2 is related to the second distance L2 and the rotation speed v of the disk;

[0046] Specifically, the difference ΔL between the first distance and the second distance satisfies the following formula:

[0047] Where L0 is the standard distance, is the correction coefficient, in mm, and v0 is the standard speed. The value range of is 18mm-22mm. In the embodiment of the present invention, Select 20 mm for calculation, the value of L0 is 50 mm, and the value of v0 is 20000 rpm.

[0048] like Figure 4As shown, the symmetry axis X1 of the radial section of the secondary atomization zone 03 intersects the rotation axis at right angles and is parallel to the surface of the flat flow zone. The symmetry axis is located on the upper surface of the flat flow zone. There is a certain gap G between the two, and the size of the gap G is 0.01mm-0.05mm; the secondary atomization zone 03 includes a flow-on portion 030 and a flow-guiding portion 031. The surface of the radial section of the flow-on portion 030 is a first arc A1. The center of curvature of the first arc A1 is set away from the center of the disk relative to the first arc and the radius of curvature is 0.1mm-0.5mm; the flow-guiding portion 031 includes an upper flow-guiding portion and a lower flow-guiding portion. The surfaces of the radial sections of the upper and lower flow-guiding portions are The second arc A2, the center of curvature of the second arc A2 is arranged close to the center of the disc relative to the second arc A2, and the curvature radius of the second arc ranges from 5mm to 10mm; the angle between the tangent of the second arc A2 and the intersection of the upper surface and the lower surface of the secondary atomization zone and the plane perpendicular to the rotation axis of the disc and passing through the intersection is 100°-130°, specifically, the intersection P1 of the second arc A2 and the upper surface of the secondary atomization zone, the intersection P2 of the second arc A2 and the lower surface of the secondary atomization zone, taking point P2 as an example, the angle α between the tangent of the second arc A2 at point P2 and the plane perpendicular to the rotation axis of the disc and passing through the intersection is 100°-130°. Since the disc rotation speed of the present application is quite high, the small-scale changes in the above-mentioned dimensions and angles will be closely related to the quality of the zinc-based spherical powder finally prepared. First, in the technical solution of the present invention, the secondary atomization zone 03 guides the semi-solidified droplets after secondary atomization to flow out from both sides through the arcs on both sides of the symmetry axis X1, thereby increasing the droplet throwing area. Compared with the prior art in which droplets are only thrown out through the edge, the probability of collision between droplets is reduced, thereby reducing the generation of peanut-shaped powder; secondly, the size of the gap G is 0.01mm-0.05mm, and the curvature radius of the first arc of the frontal part is 0.1mm-0.5mm. The above-mentioned size combination can reduce the irregular powder, that is, the adhesion of two droplets causes the prepared metal powder to be peanut-shaped, such as Figure 5 As shown, the reason is that when the above dimensions are adopted, while ensuring the secondary impact atomization effect of the droplets, the droplets have a good diversion effect on both sides of the symmetry axis, that is, the upper surface and the lower surface of the secondary atomization zone can have roughly the same droplet mass flow rate, and combined with the setting of the first arc and the second arc, the formation of a dead zone is avoided.

[0049] In the embodiment of the present invention, the “disc center” refers to the center position of the rotating disk, that is, the point position; and the “rotation axis” refers to the rotation axis of the disk during its rotation, which is a virtual straight line.

[0050] An embodiment of the present invention further provides an orthopedic medical 3D printing zinc-based spherical powder, which is prepared by the above-mentioned preparation method.

[0051] In order to qualitatively describe the prepared orthopedic medical 3D printing zinc-based spherical powder, the present invention adopts the following characterization method:

[0052] (1) The morphology of the prepared zinc-based spherical powder was observed by SEM.

[0053] (2) Count the number of hollow powders in at least 300 zinc-based spherical powders by light microscopy and calculate the hollow powder rate.

[0054] (3) The distribution of zinc-based spherical powders was statistically analyzed to obtain the D10 and D90 particle sizes, and the degree of particle size aggregation of the spherical powders was calculated.

[0055] (4) The bulk density of zinc-based spherical powder was tested using the funnel method (GB / T 1479.1-2011). The flowability of zinc-based spherical powder was tested using the standard funnel method (GB / T 1482-2010). The smaller the bulk density value, the smaller the flowability, indicating that the powder particle size is more concentrated and the sphericity is better.

[0056] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0057] Example 1: This example provides a zinc-based spherical powder for orthopedic 3D printing and a preparation method, wherein the zinc-based metal composition is: Zn: 95%, Cu: 5.0%. It includes:

[0058] S1. Prepare a zinc-based metal melt that meets the composition requirements. If the liquidus temperature of the metal melt is 480°C, then the temperature of the zinc-based metal melt can be maintained at 490°C.

[0059] S2. The zinc-based metal melt is drained to the center of a high-speed rotating disk, and after rotation acceleration, the melt is split, formed into balls, cooled, and solidified to obtain a zinc-based spherical powder material.

[0060] The distance between the outlet of the zinc-based metal melt and the disc is 40 cm, the flow rate of the zinc-based metal melt is 4.0 kg / min, the rotation speed of the disc is 40,000 rpm, and the heating temperature of the disc is 485°C.

[0061] The circumferential cross-sectional area of ​​the disc connecting portion accounts for 1 / 12 of the circumferential area.

[0062] The second distance L2 of the present invention is 300 mm, which can be calculated by the formula:

[0063] The size of ΔL is 3.6 mm, the axis of symmetry of the radial cross-section of the secondary atomization zone intersects the rotation axis perpendicularly and is parallel to the surface of the advection zone, the axis of symmetry is located on the upper surface of the advection zone, and there is a certain gap between the two, the size of the gap is 0.03 mm, the first arc and the second arc are both circular arcs, the curvature radius of the first arc is 0.2 mm, the curvature radius of the second arc is 8 mm, and the angle between the tangent of the intersection of the second arc and the upper and lower surfaces of the secondary atomization zone and the plane perpendicular to the rotation axis of the disc and passing through the intersection is 120°.

[0064] S3. Screening the zinc-based spherical powder material to obtain the zinc-based spherical powder.

[0065] Example 2: This example provides a zinc-based spherical powder for orthopedic 3D printing and a preparation method, wherein the zinc-based metal composition is: Zn: 95%, Cu: 5.0%. It includes:

[0066] S1. Prepare a zinc-based metal melt that meets the composition requirements. If the liquidus temperature of the metal melt is 480°C, then the temperature of the zinc-based metal melt can be maintained at 490°C.

[0067] S2. The zinc-based metal melt is drained to the center of a high-speed rotating disk, and after rotation acceleration, the melt is split, formed into balls, cooled, and solidified to obtain a zinc-based spherical powder material.

[0068] The distance between the outlet of the zinc-based metal melt and the disc is 30 cm, the flow rate of the zinc-based metal melt is 2.5 kg / min, the rotation speed of the disc is 20,000 rpm, and the heating temperature of the disc is 485°C.

[0069] The circumferential cross-sectional area of ​​the disc connecting portion accounts for 1 / 12 of the circumferential area.

[0070] The second distance L2 of the present invention is 300 mm, which can be calculated by the formula:

[0071] The size of ΔL is 4.7 mm, the axis of symmetry of the radial cross-section of the secondary atomization zone intersects the rotation axis perpendicularly and is parallel to the surface of the advection zone, the axis of symmetry is located on the upper surface of the advection zone, and there is a certain gap between the two, the size of the gap is 0.03 mm, the first arc and the second arc are both circular arcs, the curvature radius of the first arc is 0.2 mm, the curvature radius of the second arc is 8 mm, and the angle between the tangent of the intersection of the second arc and the upper and lower surfaces of the secondary atomization zone and the plane perpendicular to the rotation axis of the disc and passing through the intersection is 120°.

[0072] S3. Screening the zinc-based spherical powder material to obtain the zinc-based spherical powder.

[0073] Example 3: This example provides a zinc-based spherical powder for orthopedic 3D printing and a preparation method, wherein the zinc-based metal composition is: Zn: 95%, Cu: 5.0%. It includes:

[0074] S1. Prepare a zinc-based metal melt that meets the composition requirements. The liquidus temperature of the metal melt is 480°C, so the temperature of the zinc-based metal melt can be maintained at 530°C.

[0075] S2. The zinc-based metal melt is drained to the center of a high-speed rotating disk, and after rotation acceleration, the melt is split, formed into balls, cooled, and solidified to obtain a zinc-based spherical powder material.

[0076] The distance between the outlet of the zinc-based metal melt and the disc is 50 cm, the flow rate of the zinc-based metal melt is 5.0 kg / min, the rotation speed of the disc is 60,000 rpm, and the heating temperature of the disc is 485°C.

[0077] The circumferential cross-sectional area of ​​the disc connecting portion accounts for 1 / 12 of the circumferential area.

[0078] The second distance L2 of the present invention is 300 mm, which can be calculated by the formula:

[0079] The size of ΔL is 3.0 mm, the axis of symmetry of the radial cross-section of the secondary atomization zone intersects the rotation axis perpendicularly and is parallel to the surface of the advection zone, the axis of symmetry is located on the upper surface of the advection zone, and there is a certain gap between the two, the size of the gap is 0.03 mm, the first arc and the second arc are both circular arcs, the curvature radius of the first arc is 0.2 mm, the curvature radius of the second arc is 8 mm, and the angle between the tangent of the intersection of the second arc and the upper and lower surfaces of the secondary atomization zone and the plane perpendicular to the rotation axis of the disc and passing through the intersection is 120°.

[0080] S3. Screening the zinc-based spherical powder material to obtain the zinc-based spherical powder.

[0081] Example 4: Different from Example 1, in step S2 of this example, the circumferential cross-sectional area of ​​the disc connecting portion accounts for 1 / 12 of the circumferential area.

[0082] The second distance L2 of the present invention is 50 mm, which can be calculated by the formula:

[0083] The size of ΔL is 5.7 mm, the axis of symmetry of the radial cross-section of the secondary atomization zone intersects the rotation axis perpendicularly and is parallel to the surface of the advection zone, the axis of symmetry is located on the upper surface of the advection zone, and there is a certain gap between the two, the size of the gap is 0.01 mm, the first arc and the second arc are both circular arcs, the curvature radius of the first arc is 0.1 mm, the curvature radius of the second arc is 5 mm, and the angle between the tangent of the intersection of the second arc and the upper and lower surfaces of the secondary atomization zone and the plane perpendicular to the rotation axis of the disc and passing through the intersection is 100°.

[0084] Example 5: Different from Example 1, in step S2 of this example, the circumferential cross-sectional area of ​​the disc connecting portion accounts for 1 / 12 of the circumferential area.

[0085] The second distance L2 of the present invention is 200 mm, which can be calculated by the formula:

[0086] The size of ΔL is 4 mm, the axis of symmetry of the radial cross-section of the secondary atomization zone intersects the rotation axis perpendicularly and is parallel to the surface of the advection zone, the axis of symmetry is located on the upper surface of the advection zone, and there is a certain gap between the two, the size of the gap is 0.05 mm, the first arc and the second arc are both circular arcs, the curvature radius of the first arc is 0.5 mm, the curvature radius of the second arc is 10 mm, and the angle between the tangent of the intersection of the second arc and the upper and lower surfaces of the secondary atomization zone and the plane perpendicular to the rotation axis of the disc and passing through the intersection is 130°.

[0087] Example 6: This example provides a zinc-based spherical powder for orthopedic 3D printing and a preparation method, wherein the zinc-based metal composition is: Zn: 96%, Al: 4.0%. It includes:

[0088] S1. Prepare a zinc-based metal melt that meets the composition requirements. The liquidus temperature of the metal melt is 675°C, so the temperature of the zinc-based metal melt is maintained at 685°C.

[0089] S2. The zinc-based metal melt is drained to the center of a high-speed rotating disk, and after rotation acceleration, the melt is split, formed into balls, cooled, and solidified to obtain a zinc-based spherical powder material.

[0090] The distance between the outlet of the zinc-based metal melt and the disc is 40 cm, the flow rate of the zinc-based metal melt is 4.0 kg / min, the rotation speed of the disc is 40,000 rpm, and the heating temperature of the disc is 680°C.

[0091] The circumferential cross-sectional area of ​​the disc connecting portion accounts for 1 / 12 of the circumferential area.

[0092] The second distance L2 of the present invention is 300 mm, which can be calculated by the formula:

[0093] The size of ΔL is 3.6 mm, the axis of symmetry of the radial cross-section of the secondary atomization zone intersects the rotation axis perpendicularly and is parallel to the surface of the advection zone, the axis of symmetry is located on the upper surface of the advection zone, and there is a certain gap between the two, the size of the gap is 0.03 mm, the first arc and the second arc are both circular arcs, the curvature radius of the first arc is 0.2 mm, the curvature radius of the second arc is 8 mm, and the angle between the tangent of the intersection of the second arc and the upper and lower surfaces of the secondary atomization zone and the plane perpendicular to the rotation axis of the disc and passing through the intersection is 120°.

[0094] S3. Screening the zinc-based spherical powder material to obtain the zinc-based spherical powder.

[0095] Comparative Example 1: Different from Example 1, the disc in this comparative example does not have a secondary atomization zone.

[0096] Comparative Example 2: Different from Example 1, in this comparative example, the distance between the outlet of the zinc-based metal melt and the disc is 60 cm, and the flow rate of the zinc-based metal melt is 6 kg / min.

[0097] Comparative Example 3: Different from Example 1, in this comparative example, the rotation speed of the disc is 15000 rpm.

[0098] Comparative Example 4: Different from Example 1, in this comparative example, the rotation speed of the disc is 70,000 rpm.

[0099] Comparative Example 5: Different from Example 1, in this comparative example, the size of ΔL is 3 mm.

[0100] Comparative Example 6: Different from Example 1, in this comparative example, the size of ΔL is 4 mm

[0101] Comparative Example 7: Different from Example 1, in this comparative example, the first arc does not exist, that is, the second arc is directly intersected.

[0102] Comparative Example 8: Different from Example 1, in this comparative example, the curvature radius of the second arc is 12 mm.

[0103] Since the SEM images of the zinc-based spherical powders prepared in Examples 1-6 are similar, Example 1 is used as a typical example for illustration. Figure 6 As shown in a and b, the prepared zinc-based spherical powder has high sphericity and no peanut-shaped powder exists, which indicates that the technical solution provided by the present invention can significantly reduce the collision probability of droplets after leaving the turntable.

[0104] The zinc-based spherical powder prepared in Comparative Example 1 is as follows Figure 7 As shown in a and b in the figure, it can be seen that the lack of a secondary atomization zone results in more hollow zinc-based spherical powder being prepared. The reason is that the metal melt reacts with the inert gas medium after splitting at the edge of the disk. At this time, the viscosity of the metal droplets is low, causing them to be impacted by the gas to form hollow powder. Secondly, peanut-shaped powder also exists in the prepared powder.

[0105] The zinc-based spherical powders prepared in Examples 1-6 and Comparative Examples 1-8 were characterized, and the obtained test data are shown in Table 1.

[0106] Table 1 Performance test data of various embodiments and comparative examples

[0107]

[0108] As can be seen from the above data, the technical solution provided by the embodiment of the present invention has less hollow rate, powder particle size concentration is high, and the characteristics such as fluidity is good. By Example 1 and Comparative Example 1, it can be known that the setting of secondary atomization zone can significantly reduce hollow powder rate and powder particle size concentration, has good fluidity, and the poor powder particle size concentration causes loose density to be higher. By Example 1 and Comparative Example 2, it can be known that the outlet of zinc-based metal melt and the flow rate of the distance between the disk and the zinc-based metal melt also can make the prepared zinc-based metal powder quality decline, and its reason is that, larger melt impact force and high flow rate, limit the current limiting, the balancing flow effect in the impact zone, make the prepared powder hollow rate higher, and particle size concentration is larger, and loose density is large and fluidity is on the weak side. By Example 1, Comparative Examples 3 and 4, it can be known that the rotating speed of disk also can affect the quality of zinc-based metal powder, and the rotating speed is little and the rotating speed is large and all makes the balancing flow effect in the impact zone weaken, thereby making the quality of zinc-based metal powder reduce. As can be seen from Example 1, Comparative Examples 5 and 6, the size of ΔL is very critical. If the size is too small, the cooling intensity of the droplets thrown out of the advection zone is low, resulting in an increase in the hollow powder rate. If the size is too large, the cooling intensity is too high, the secondary atomization effect is weakened, resulting in an increase in bulk density and poor fluidity. As can be seen from Example 1 and Comparative Example 7, the frontal portion is very important. It is mainly used for secondary atomization and reducing droplet velocity. The absence of the frontal portion significantly increases the hollow powder rate, reduces the concentration of the powder particle size distribution, and poors fluidity. As can be seen from Example 1 and Comparative Example 8, the curvature radius of the second arc is large, affecting the flow field coordinated with the first arc, forming a partial dead zone, and thus significantly reducing the powder fluidity.

[0109] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing orthopedic medical 3D printing zinc-based spherical powder, characterized in that: include: Prepare zinc-based metal melt that meets composition requirements; The zinc-based metal melt is directed to the center of a high-speed rotating disk, and after accelerated rotation, is split, formed into balls, cooled, and solidified to obtain a zinc-based spherical powder material; Sieving the zinc-based spherical powder material to obtain the zinc-based spherical powder; The zinc-based metal comprises, by mass percentage, Cu: 0.1%-7.0%, Mg: 0.02%-0.10%, Al: 3.5%-4.5%, Li≤0.01%, Mn≤0.02%, and the remainder is Zn; The disc has an impact zone, a flat flow zone and a secondary atomization zone; The impact zone is located in the middle of the disc and is used to receive the zinc-based metal melt. The impact zone has a drainage structure. The advection zone is annular and located on the side of the disk away from the center of the disk; The secondary atomization zone is annular and is located away from the center of the disk relative to the advection zone; The minimum distance between the secondary atomization zone and the rotation axis forms a first distance, the maximum distance between the advection zone of the disk and the rotation axis forms a second distance, and the difference between the first distance and the second distance is related to the second distance and the rotation speed of the disk; The difference ΔL between the first distance and the second distance satisfies the following formula: Where L2 is the second distance, L0 is the standard distance, is the correction coefficient, the unit is mm, v is the rotation speed of the disk, and v0 is the standard speed.

2. The preparation method according to claim 1, characterized in that The temperature of the zinc-based metal melt is Tm+10° C.-Tm+50° C., wherein Tm is the liquidus temperature of the zinc-based metal melt.

3. The preparation method according to claim 1, characterized in that The free vertical falling distance of the zinc-based metal melt is 30 cm to 50 cm, and the flow rate of the zinc-based metal melt is 2.5 kg / min to 5.0 kg / min.

4. The preparation method according to claim 1, characterized in that The rotation speed of the disc is 20000 rpm-60000 rpm.

5. The preparation method according to claim 1, characterized in that The drainage structure is a hemispherical protrusion arranged in the impact area. The diameter of the hemispherical protrusion is 0.5mm-2.5mm, and the diameter of the hemispherical protrusion gradually increases as it moves away from the center of the disc.

6. The preparation method according to claim 5, characterized in that The impact zone and the advection zone are heated at a temperature of Tm+5°C to Tm+10°C, wherein Tm is the liquidus temperature of the zinc-based metal melt.

7. The preparation method according to claim 6, characterized in that The secondary atomization zone is connected to the flat flow zone via a connecting portion, and the circumferential cross-sectional area of ​​the connecting portion does not exceed 1 / 10 of the circumferential area.

8. The preparation method according to claim 1, characterized in that The symmetry axis of the radial cross section of the secondary atomization zone intersects the rotation axis perpendicularly and is parallel to the surface of the advection zone. The symmetry axis is located on the upper surface of the advection zone, and there is a gap between the two. The size of the gap is 0.01 mm to 0.05 mm. The secondary atomization zone includes a flow-facing portion and a flow-guiding portion, wherein the surface of the radial cross-section of the flow-facing portion is a first arc, the center of curvature of the first arc is arranged away from the center of the disk relative to the first arc, and the curvature radius is 0.1 mm to 0.5 mm; The guide portion includes an upper guide portion and a lower guide portion, the surfaces of the radial cross-sections of the upper guide portion and the lower guide portion are second arcs, the center of curvature of the second arc is arranged close to the center of the disc relative to the second arc, and the curvature radius of the second arc ranges from 5 mm to 10 mm; the angle between the tangent of the intersection of the second arc and the upper and lower surfaces of the secondary atomization zone and the plane perpendicular to the rotation axis of the disc and passing through the intersection is 100°-130°.

9. A zinc-based spherical powder for orthopedic 3D printing, characterized in that: The orthopedic medical 3D printing zinc-based spherical powder is prepared by the preparation method described in any one of claims 1 to 8.

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