Titanium alloy curved surface rapid forming device and method

Abstract

The invention belongs to the technical field of titanium alloy forming, and particularly relates to a titanium alloy curved surface rapid forming device and method. The device comprises a vacuum chamber, a powder feeding mechanism, a powder box, a quantitative powder sending device, a powder spreading device, an electron beam generator, a forming mechanism and a discharging mechanism, the electron beam generator and the powder box are arranged at the top of the inner side of the vacuum chamber, the powder box is connected with the powder feeding mechanism, and the quantitative powder sending device is arranged at the bottom of the powder box; the powder spreading device, the lifting platform and the discharging mechanism are sequentially arranged at the bottom of the vacuum chamber, and the titanium alloy powder in the forming mechanism is printed and formed into the porous titanium artificial tooth root implant by the electron beam generator; the powder spreading device pushes quantitative powder to the forming mechanism and pushes the porous titanium artificial tooth root implant into the discharging mechanism, and the discharging mechanism carries out dust removal and heat treatment on the porous titanium artificial tooth root implant. According to the invention, precise control of aperture and pore structure in the forming process is realized, and pores are connected and communicated with each other, so that the biocompatibility of the material is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of titanium alloy forming, and in particular relates to a titanium alloy curved surface rapid forming device and method. Background Art

[0002] Titanium and titanium alloys are widely used in the manufacture of artificial joints, tooth roots and other plastic implants due to their excellent mechanical properties, biocompatibility and corrosion resistance. In order to achieve permanent or semi-permanent biological fixation of the implant, a layer of porous material coating is usually prepared on the surface of the implant in order to achieve permanent or semi-permanent biological fixation. However, the porous coating is usually very thin, and there is a high elastic modulus gradient between the solid matrix and the porous coating. The solid matrix bears almost all the load. Although the porous coating on the surface can solve the biological fixation of the surface, it still cannot avoid the "stress shielding" phenomenon caused by the mismatch between the mechanical properties of the implant and the bone tissue, resulting in little new bone growing into the pores, or bone atrophy around the implant under long-term use conditions. Due to the pore structure of porous materials, the elastic modulus can be adjusted to a range that matches natural bones. Therefore, using porous materials as the entire implant can not only permanently or semi-permanently fix the implant to the surface of bone tissue, but also because the mechanical properties of the implant match those of bone tissue, the implant can minimize the "stress shielding" phenomenon and subsequent bone atrophy. This has led to the development of biomedical porous titanium materials.

[0003] In order to form pores and better control the porosity and pore morphology, the usual preparation method is to mix titanium powder, pore formers and binders, press them into shape, and then sinter them in a vacuum furnace. Since titanium is chemically active at high temperatures, the removal temperature of pore formers and binders is already higher than the oxidation temperature of titanium, so the pore formers and binders must be removed under vacuum conditions. Even so, a large amount of volatilization and carbonization of pore formers or binders will participate in the sintering process of titanium, affecting the performance of the material. Moreover, due to volatilization, the pore walls of the formed pores contain a large number of micropores, which are very likely to produce stress concentration when subjected to force, thereby causing the mechanical properties of porous titanium to decrease. In addition, removing the residual carbonization products of the pore formers and binders under vacuum conditions will cause great damage to the vacuum equipment, so the cost is relatively high. Summary of the invention

[0004] In view of the above problems, the object of the present invention is to provide a titanium alloy curved surface rapid prototyping device and method to obtain biomedical titanium alloy curved surface molded parts with no pollution and high mechanical properties.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: On the one hand, the present invention provides a titanium alloy curved surface rapid prototyping device, comprising a vacuum chamber, a powder feeding mechanism, a powder box, a quantitative powder dispenser, a powder spreader, an electron beam generator, a forming mechanism and a discharging mechanism, wherein the powder box is arranged at the inner top of the vacuum chamber and is connected to the powder feeding mechanism, the powder feeding mechanism provides titanium alloy powder to the powder box, the quantitative powder dispenser is arranged at the bottom of the powder box for quantitative powder dropping; the powder spreader, a lifting platform and the discharging mechanism are arranged at the bottom of the vacuum chamber in sequence, the electron beam generator is arranged at the top of the vacuum chamber, the electron beam generator is used to emit an electron beam to the titanium alloy powder in the forming mechanism, and print the titanium alloy powder into a porous titanium artificial tooth root implant; the powder spreader is used to push the quantitative powder sent by the quantitative powder dispenser onto the forming mechanism and push the porous titanium artificial tooth root implant formed on the forming mechanism into the discharging mechanism, and the discharging mechanism is used to remove dust and heat treat the porous titanium artificial tooth root implant.

[0006] In one possible implementation, the forming mechanism includes a forming cylinder and a lifting platform, wherein the lifting platform is slidably arranged in the forming cylinder; when the lifting platform is in a lowered position, it receives a certain amount of powder pushed by the powder spreader, and when the lifting platform rises, it lifts the printed porous titanium artificial tooth root implant.

[0007] In one possible implementation, a preheater for preheating the titanium alloy powder is provided on the top of the powder box.

[0008] In one possible implementation, the powder feeding mechanism is arranged in the feed port at the top of the powder box; the powder feeding mechanism includes an outer powder feeding vacuum gate valve, a buffer hopper and an inner powder feeding vacuum gate valve arranged from top to bottom, and the vacuum feeding of the powder box is achieved by alternately opening and closing the outer powder feeding vacuum gate valve and the inner powder feeding vacuum gate valve.

[0009] In one possible implementation, the discharging mechanism includes a vacuum ultrasonic vibration table, a discharge bin and a powder collecting cylinder, wherein the discharge bin is arranged at the bottom of the vacuum chamber, and a discharging vacuum gate valve is provided on the top of the discharge bin, and the discharging vacuum gate valve is used for connecting or isolating the vacuum chamber and the discharge bin; the vacuum ultrasonic vibration table and the powder collecting cylinder are arranged in the discharge bin from top to bottom, and the vacuum ultrasonic vibration table uses ultrasonic vibration to remove the titanium alloy powder inside the porous titanium artificial tooth root implant, and the titanium alloy powder falls into the powder collecting cylinder; a heating module is provided in the vacuum ultrasonic vibration table, and the porous titanium artificial tooth root implant is heated to above the recrystallization temperature by the heating module.

[0010] In one possible implementation, the upper portion of the material drop bin is connected to a pipeline, the pipeline is connected to a gas control system, the gas control system introduces inert gas into the material drop bin through the pipeline, and the porous titanium artificial tooth root implant is gradiently pressurized by the inert gas to refine the grains of the porous titanium artificial tooth root implant.

[0011] In one possible implementation, the printing trajectory of the electron beam emitted by the electron beam generator is non-linear, and the multiple printing trajectories in each layer are parallel to each other and equidistant; the direction of the printing trajectory of each layer is different, and the intersection nodes of each printing trajectory with the upper and lower layers do not overlap; the printed microstructure of the porous titanium artificial tooth root implant has non-linear penetrating pores.

[0012] Another aspect of the present invention provides a forming method using the titanium alloy curved surface rapid forming device as described above, comprising the following steps: Step S1: Modeling based on the patient's mandibular 3D CT; Step S2: The powder feeding mechanism feeds the powder box with vacuum, and the powder box preheats the titanium alloy powder; Step S3: the quantitative powder dispenser performs intermittent quantitative powder dropping, and the powder spreader pushes each quantitative powder dropped by the quantitative powder dispenser onto the lifting platform; Step S4: the electron beam generator emits an electron beam onto the titanium alloy powder on the lifting platform to perform layer-by-layer 3D printing, so as to print the titanium alloy powder into a porous titanium artificial tooth root implant; Step S5: the lifting platform rises to be flush with the bottom surface of the powder box, and the powder spreader pushes the porous titanium artificial tooth root implant into the drop bin and drops it onto the vacuum ultrasonic vibration table; Step S6: the vacuum ultrasonic vibration table uses ultrasonic vibration to remove the titanium alloy powder in the internal space of the porous titanium artificial tooth root implant, and heats the porous titanium artificial tooth root implant to recrystallize the porous titanium artificial tooth root implant; Step S7: introducing an inert gas into the material bin, applying gradient pressure to the porous titanium artificial tooth root implant through the inert gas to refine the grains of the porous titanium artificial tooth root implant, and then cooling; Step S8: taking out the porous titanium artificial tooth root implant from the material drop bin and performing surface coating treatment; Step S9: characterization of the coating and determination of the physicochemical properties of the porous titanium artificial tooth root implant; Step S10: evaluating the biological function of the porous titanium artificial tooth root implant coating.

[0013] In a possible implementation, the porous titanium artificial tooth root implant is a porous Ti15Zr alloy; In step S8, the surface coating of the porous titanium artificial tooth root implant is treated by an electrochemical method, with a graphite electrode as an anode and a porous Ti15Zr alloy as a cathode, and the process parameters are adjusted to prepare a variety of nano-coatings on the porous Ti15Zr alloy.

[0014] In a possible implementation, HA, HA-GO, HA-Ag and HA-MgO nano-coatings are prepared on the porous Ti15Zr alloy respectively by immersing the porous titanium artificial tooth root implant into different depths of electrochemical solution reaction cells.

[0015] The advantages and beneficial effects of the present invention are: a titanium alloy curved surface rapid prototyping device provided by the present invention applies electron beam melting metal rapid prototyping technology (EBM technology for short) to the preparation of titanium alloy porous materials. This method can achieve precise control of pore size and pore structure, and the pores are interconnected, which greatly improves the biocompatibility of the material and also provides a reliable technical means for achieving precise and controllable processing and preparation of porous metal materials.

[0016] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings.

[0017] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 It is a structural schematic diagram of a titanium alloy curved surface rapid prototyping device of the present invention; Figure 2 It is an axonometric view of the porous titanium artificial tooth root implant of the present invention; Figure 3 is a cross-sectional view of a porous titanium artificial tooth root implant in the present invention; Figure 4 A schematic diagram of a printing trajectory of an electron beam generator in the present invention; Figure 5 A side view of a three-layer printing track of an electron beam generator in the present invention; Figure 6 It is an axonometric diagram of the three-layer printing track of the electron beam generator in the present invention; Figure 7It is a top view of the three-layer printing track of the electron beam generator in the present invention.

[0019] In the figure: 1-vacuum chamber, 2-outer powder inlet vacuum plug valve, 3-inner powder inlet vacuum plug valve, 4- Buffer hopper, 5-powder box, 6-preheater, 7-quantitative powder generator, 8-powder spreader, 9-electron beam generator, 10-electron beam, 11-gas control system, 12-pipeline, 13-discharging vacuum gate valve, 14-upper vacuum door, 15-lower vacuum door, 16-powder collecting cylinder, 17-vacuum ultrasonic vibration table, 18-feeding bin, 19-forming cylinder, 20-porous titanium artificial tooth root implant, 21-lifting platform, 22-base plate, 23-tooth root implant body, 24-external thread, 25-internal thread, 26-printing trajectory, 27-first layer printing trajectory, 28-second layer printing trajectory, 29-third layer printing trajectory, 30-three-dimensional boundary, 31-non-linear pine needles. DETAILED DESCRIPTION

[0020] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0022] An embodiment of the present invention provides a titanium alloy curved surface rapid prototyping device, which applies electron beam melting metal rapid prototyping technology to the preparation of titanium alloy porous materials, can achieve precise control of pore size and pore structure, and the pores are interconnected and connected, greatly improving the biocompatibility of the material. Figures 1 to 7As shown, the titanium alloy curved surface rapid prototyping device comprises a vacuum chamber 1, a powder feeding mechanism, a powder box 5, a quantitative powder emitter 7, a powder spreader 8, an electron beam generator 9, a forming mechanism and a discharging mechanism, wherein a vacuum environment is established inside the vacuum chamber 1; the powder box 5 is arranged at the inner top of the vacuum chamber 1 and is connected to the powder feeding mechanism, the powder feeding mechanism provides titanium alloy powder to the powder box 5, the quantitative powder emitter 7 is arranged at the bottom of the powder box 5, and is used for quantitative powder dropping; the powder spreader 8, the lifting platform 21 and the discharging mechanism are arranged at the bottom of the vacuum chamber 1 in sequence, the electron beam generator 9 is arranged at the top of the vacuum chamber 1, the electron beam generator 9 is used to emit an electron beam 10 to the titanium alloy powder in the forming mechanism, and print the titanium alloy powder into a porous titanium artificial tooth root implant 20; the powder spreader 8 is used to push the quantitative powder sent by the quantitative powder emitter 7 onto the forming mechanism and push the porous titanium artificial tooth root implant 20 formed on the forming mechanism into the discharging mechanism, and the discharging mechanism is used to remove dust and heat treat the porous titanium artificial tooth root implant 20.

[0023] See also Figure 1 As shown, in the embodiment of the present invention, a preheater 6 for preheating and heating titanium alloy powder is provided on the top of the powder box 5. The powder feeding mechanism is arranged in the feeding port on the top of the powder box 5; the powder feeding mechanism includes an outer powder feeding vacuum gate valve 2, a buffer hopper 4 and an inner powder feeding vacuum gate valve 3 arranged from top to bottom, and the vacuum feeding of the powder box 5 is realized by alternately opening and closing the outer powder feeding vacuum gate valve 2 and the inner powder feeding vacuum gate valve 3. The outer powder feeding vacuum gate valve 2, the inner powder feeding vacuum gate valve 3 and the buffer hopper 4 are combined to ensure that the titanium powder enters the powder box 5 in the vacuum environment from the atmospheric environment, and the vacuum environment inside the vacuum chamber 1 is not destroyed. The inner powder feeding vacuum gate valve 3 is closed, and the atmospheric environment is restored in the area where the buffer hopper 4 is located. The outer powder feeding vacuum gate valve 2 is opened, and the powder is manually added to the buffer hopper 4. The outer powder feeding vacuum gate valve 2 is closed, and the vacuum environment inside the vacuum chamber 1 is established. The inner powder inlet vacuum gate valve 3 is opened, and the buffer hopper 4 is opened downward from upward under the action of the vacuum direct drive motor. The titanium powder in the buffer hopper 4 is guided by the lower hopper in the vacuum and accurately enters the powder box 5. The inner powder inlet vacuum gate valve 3 is closed, and the buffer hopper 4 is reset. In this way, the buffer hopper 4 moves in the vacuum, so there is no nano titanium powder floating.

[0024] In an embodiment of the present invention, the forming mechanism includes a forming cylinder 19 and a lifting platform 21, wherein the forming cylinder 19 is arranged at the bottom of the powder box 5, and the upper end surface of the forming cylinder 19 is coplanar with the upper surface of the bottom of the powder box 5. The lifting platform 21 can be slidably arranged in the forming cylinder 19, and the lifting platform 21 has a vacuum lifting function. When the lifting platform 21 is lowered to a low position, the powder spreader 8 pushes a certain amount of powder into the forming cylinder 19, and the lifting platform 21 receives the certain amount of powder pushed by the powder spreader 8. When the lifting platform 21 rises, the printed porous titanium artificial tooth root implant 20 is lifted into the powder box 5, which is convenient for the powder spreader 8 to push.

[0025] Specifically, the electron beam generator 9 emits an electron beam 10 to the titanium alloy powder on the lifting platform 21, first prints the substrate 22, then performs EBM forming layer by layer on the substrate 22, and prints multiple porous titanium artificial tooth root implants 20 with high throughput.

[0026] In an embodiment of the present invention, the discharging mechanism includes a vacuum ultrasonic vibration table 17, a discharge bin 18 and a powder collecting tube 16, wherein the discharge bin 18 is arranged at the bottom of the vacuum chamber 1, and a discharging vacuum gate valve 13 is provided on the top of the discharge bin 18, and the discharging vacuum gate valve 13 is used for connecting or isolating the vacuum chamber 1 and the discharge bin 18; the vacuum ultrasonic vibration table 17 and the powder collecting tube 16 are arranged in the discharge bin 18 from top to bottom, and the vacuum ultrasonic vibration table 17 uses ultrasonic vibration to remove the titanium alloy powder inside the porous titanium artificial tooth root implant 20, and the titanium alloy powder falls into the powder collecting tube 16 through the hopper below the vacuum ultrasonic vibration table 17; a heating module is provided in the vacuum ultrasonic vibration table 17, and the porous titanium artificial tooth root implant 20 is heated to above the recrystallization temperature by the heating module.

[0027] In this embodiment, the principle of removing nano titanium powder by vacuum ultrasonic vibration table 17 is different from that of ultrasonic vacuum cleaning machine. The principle of removing nano titanium powder inside porous titanium artificial tooth root implant 20 by vacuum ultrasonic vibration table 17 is that chicken feathers and iron balls fall to the ground at the same time in vacuum, so there will be no nano titanium powder floating, thereby avoiding the operator from inhaling titanium alloy dust, which is beneficial to the health and safety of the operator. The traditional method of using blasting to remove dust from porous human implant bones is not suitable for dental implants.

[0028] Furthermore, the upper part of the material bin 18 is connected to the pipeline 12, and the pipeline 12 is connected to the gas control system 11; the discharge vacuum gate valve 13 isolates the vacuum ultrasonic vibration table 17 from the space in the vacuum chamber 1, and the gas control system 11 introduces inert gas into the material bin 18 through the pipeline 12, and the porous titanium artificial tooth root implant 20 is gradient pressurized by the inert gas to refine the grains of the porous titanium artificial tooth root implant 20. The gradient pressurization strategy is formulated by fluid and solid conjugate thermodynamics simulation and crystallization process simulation software, and is determined by subsequent experiments.

[0029] The gas control system 11 restores the pressure in the drop bin 18 to atmospheric pressure through the pipeline 12 , and the multiple porous titanium artificial tooth root implants 20 are taken out from the upper vacuum door 14 , and the powder collection tube 16 is taken out from the lower vacuum door 15 .

[0030] See also Figure 2 , Figure 3 As shown, in the embodiment of the present invention, the porous titanium artificial tooth root implant 20 includes a tooth root implant body 23, which is a hollow cone, and the inner and outer surfaces are respectively provided with an internal thread 25 and an external thread 24, the external thread 24 is used to fix with the mandible, and the internal thread 25 is used to lock with the base and the crown. Because each person's mandible is different, the multiple porous titanium artificial tooth root implants 20 printed on the substrate 22 are different, and the specific size and length are customized according to the patient's mandible 3D CT modeling.

[0031] See also Figures 4 to 7 As shown, in an embodiment of the present invention, the printing trajectory 26 of the electron beam 10 emitted by the electron beam generator 9 is a non-straight line, preferably an S-shaped trajectory; the multiple printing trajectories 26 in each layer are parallel to each other and equidistant, and horizontal non-straight holes are formed between two adjacent printing trajectories 26; the printing trajectories 26 of each layer have different directions, forming a grid shape, and each printing trajectory 26 does not overlap with the intersection nodes of the upper and lower layers.

[0032] Specifically, taking the three-layer printing track as an example, the horizontal projections of the printed connection nodes between the first layer printing track 27, the second layer printing track 28 and the third layer printing track 29 do not overlap. Therefore, the printed microstructure of the porous titanium artificial tooth root implant 20 has non-linear pores, that is, all the holes in each layer are connected in the upper and lower spaces. In other words, a printing track 26 does not overlap with the printing nodes of the lower and upper layers. This layout can be suitable for the effect of anisotropy in the pressure direction and other directions of the teeth.

[0033] See also Figure 7 As shown, in the embodiment of the present invention, the porous titanium artificial tooth root implant 20 contains non-linear pine needles 31 outside the three-dimensional boundary 30. The non-linear pine needles 31 can effectively penetrate into the mandibular bone and have a strengthening fixation effect.

[0034] In this embodiment, the material of the porous titanium artificial tooth root implant 20 is preferably Ti15Zr alloy, with a compression strength ≥100 MPa, a porosity ≥30%, and an elastic modulus ≤20 GPa.

[0035] The present invention provides a titanium alloy curved surface rapid prototyping device, which applies electron beam melting metal rapid prototyping technology (EBM technology for short) to the preparation of titanium alloy porous materials, and can achieve precise control of pore size and pore structure. The pores are interconnected and connected, which greatly improves the biocompatibility of the material and provides a reliable technical means for achieving precise and controllable processing and preparation of porous metal materials.

[0036] Based on the above design concept, another embodiment of the present invention provides a forming method using the titanium alloy curved surface rapid forming device in the above embodiment, see Figures 1 to 7 As shown, the molding method comprises the following steps: Step S1: Modeling based on the patient's mandibular 3D CT; Specifically based on the patient's mandibular 3D model, high-throughput personalized customization and design of multiple 3D models of tissues to be implanted; the 3D model of the tissue to be implanted is obtained, then sliced ​​and imported into the 3D printer; Step S2: the powder feeding mechanism feeds the powder box 5 with vacuum, and the powder box 5 preheats the titanium alloy powder; Specifically, the titanium alloy powder is obtained by ultrasonic gas atomization powder making method to obtain a powder with a diameter of 40-70 μm; Step S3: the quantitative powder dispenser 7 performs intermittent quantitative powder dropping, and the powder spreader 8 pushes each quantitative powder dropped by the quantitative powder dispenser 7 onto the lifting platform 21; Step S4: the electron beam generator 9 emits an electron beam 10 to the titanium alloy powder on the lifting platform 21 to perform layer-by-layer 3D printing, and prints the titanium alloy powder into a porous titanium artificial tooth root implant 20; Step S5: the lifting platform 21 rises to be flush with the bottom surface of the powder box 5, and the powder spreader 8 pushes the porous titanium artificial tooth root implant 20 into the drop bin 18 and drops it onto the vacuum ultrasonic vibration table 17; Step S6: The vacuum ultrasonic vibration table 17 uses ultrasonic vibration to remove the titanium alloy powder in the internal space of the porous titanium artificial tooth root implant 20, and heats the porous titanium artificial tooth root implant 20 to above the recrystallization temperature to recrystallize the porous titanium artificial tooth root implant 20; Step S7: Inert gas is introduced into the material bin 18, and the porous titanium artificial tooth root implant 20 is subjected to gradient pressurization by the inert gas to refine the grains of the porous titanium artificial tooth root implant 20, and then cooled; specifically, the inert gas is high-pressure nitrogen; Step S8: taking out the porous titanium artificial tooth root implant 20 from the material bin 18 and performing surface coating treatment; Step S9: characterizing the coating and measuring the physical and chemical properties of the porous titanium artificial tooth root implant 20; Step S10: evaluating the biological function of the coating of the porous titanium artificial tooth root implant 20 .

[0037] In this embodiment, the porous titanium artificial tooth root implant 20 is a porous Ti15Zr alloy.

[0038] In step S8, the surface coating treatment of the porous titanium artificial tooth root implant 20 adopts an electrochemical method, with a graphite electrode as an anode and a porous Ti15Zr alloy as a cathode, and the process parameters are adjusted to prepare a variety of nano coatings on the porous Ti15Zr alloy.

[0039] Specifically, the porous titanium artificial tooth root implant 20 is immersed in different electrochemical solution reaction pools at different depths, such as the depth of HA being penetrated is different from the depth of GO being penetrated, and HA, HA-GO, HA-Ag and HA-MgO nano-coatings are prepared on the porous Ti15Zr alloy.

[0040] In step S9 , the coating characterization and physical and chemical property determination of the porous titanium artificial tooth root implant 20 include but are not limited to the following three aspects.

[0041] 1) The microstructure, surface morphology and surface roughness of the porous Ti15Zr alloy and coating were observed using scanning electron microscopy and atomic mechanics microscopy, the influence of process parameters on the coating morphology was analyzed, and the elemental composition of the material surface was qualitatively analyzed using X-ray photoelectron spectroscopy.

[0042] 2) The corrosion resistance, bonding force and mechanical strength of the coating were analyzed using an electrochemical workstation and a multifunctional material surface performance tester; the hydrophilicity and hydrophobicity of the coating were analyzed using the solid-liquid contact angle method.

[0043] 3) The antibacterial property of the coating was tested using Escherichia coli and Staphylococcus aureus. The absorbance value of each ion in the immersion solution was detected using an ELISA instrument to investigate the physiological stability of the coating.

[0044] In step S10, including but not limited to, using existing technology to evaluate the cell compatibility of the implant, in accordance with the GB / T16886 series of standards for biological evaluation of biomedical materials in my country.

[0045] For steps S1 to S7, 3D modeling structural design software was used to design uniform porous structures with different pore shapes, pore sizes, and porosities. The effects of process parameters such as electron beam spot size, scanning energy, scanning speed, number of electron beams, and cooling rate on the pore wall structure of porous Ti15Zr alloy were studied. The influencing factors of precise preparation of porous Ti15Zr alloy by EBM were discussed.

[0046] For steps S8 to S9, the preparation process of HA, HA-GO, HA-Ag and HA-MgO coatings on the surface of porous Ti15Zr alloy can be studied, the microstructure of the coating and the characterization element composition can be analyzed, the bonding force, mechanical strength and physiological stability of the porous Ti15Zr alloy coating can be studied, and the hydrophilic and hydrophobic properties, corrosion resistance and antibacterial behavior of the coating can be explored.

[0047] The preparation method of porous titanium medical implant bone screw for tooth root other than electron beam powder bed and laser powder bed cannot be compared with the preparation of porous titanium medical implant bone screw by electron beam powder bed and laser powder bed due to the element contamination problem of curved surface forming mold and the problem of porous shape control. The preparation of porous titanium artificial tooth root implant by electron beam powder bed of the present invention has the key point of economic industrialization. The commercial electron beam powder bed is 3kw, which has the advantages of high power and high forming efficiency compared with the laser powder bed of 1kw. However, compared with the laser powder bed, the electron beam powder bed requires a vacuum environment. The key to solving the cost problem is industrialization. The specific solution is that the present invention optimizes and improves the existing electron beam powder bed 3D porous titanium printing equipment, introduces vacuum additional devices and processes, and allows the electron beam 3D printing time, high-throughput porous titanium artificial tooth root implant cooling time and vacuum breaking time to run in parallel, and can achieve continuous production.

[0048] The present invention provides a titanium alloy curved surface rapid prototyping method, which can achieve precise control of pore size and pore structure, and the pores are interconnected, which greatly improves the biocompatibility of the material and provides a reliable technical means for realizing precise controllable processing and preparation of porous metal materials. The high temperature during the melting process of titanium alloy powder will cause the grains in the material to grow, and will also cause changes in solid solubility. These problems cause the microstructure of the melting area to be different from that of the substrate, which is prone to cracks, resulting in increased brittleness of the material and affecting its mechanical properties. The present invention adopts a high-pressure nitrogen controllable temperature reduction gradient measure to solve the problem of brittleness of porous titanium implants manufactured by electron beam melting technology. At the same time, the outer shell of the vacuum chamber 1 contains water cooling, and the vacuum chamber contains an infinite continuous powder supply.

[0049] The present invention utilizes the vacuum ultrasonic vibration table 17 to remove the nano titanium powder inside the porous titanium artificial tooth root implant 20, so there will be no nano titanium powder scattering, thereby preventing the operator from inhaling titanium alloy dust, which is beneficial to the health and safety of the operator.

[0050] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A titanium alloy curved surface rapid prototyping device, characterized in that: The invention comprises a vacuum chamber (1), a powder feeding mechanism, a powder box (5), a quantitative powder generator (7), a powder spreader (8), an electron beam generator (9), a forming mechanism and a discharging mechanism, wherein the powder box (5) is arranged at the inner top of the vacuum chamber (1) and is connected to the powder feeding mechanism, the powder feeding mechanism provides titanium alloy powder to the powder box (5), the quantitative powder generator (7) is arranged at the bottom of the powder box (5) and is used for quantitative powder dropping; the powder spreader (8), the lifting platform (21) and the discharging mechanism are arranged at the bottom of the vacuum chamber (1) in sequence, and the electron beam generator (9) is connected to the powder feeding mechanism. The device (9) is arranged on the top of the vacuum chamber (1); the electron beam generator (9) is used to emit an electron beam (10) to the titanium alloy powder in the forming mechanism, so as to print and shape the titanium alloy powder into a porous titanium artificial tooth root implant (20); the powder spreader (8) is used to push the quantitative powder sent by the quantitative powder emitter (7) onto the forming mechanism and push the porous titanium artificial tooth root implant (20) formed on the forming mechanism into the discharging mechanism, and the discharging mechanism is used to perform dust removal and heat treatment on the porous titanium artificial tooth root implant (20).

2. The titanium alloy curved surface rapid prototyping device according to claim 1, characterized in that: The forming mechanism comprises a forming cylinder (19) and a lifting platform (21), wherein the lifting platform (21) is arranged in the forming cylinder (19) so as to be able to slide up and down; when the lifting platform (21) is in a descending position, it receives a fixed amount of powder pushed by a powder spreader (8), and when the lifting platform (21) rises, it lifts the printed porous titanium artificial tooth root implant (20).

3. The titanium alloy curved surface rapid prototyping device according to claim 2, characterized in that: A preheater (6) for preheating titanium alloy powder is provided on the top of the powder box (5).

4. The titanium alloy curved surface rapid prototyping device according to claim 2, characterized in that: The powder feeding mechanism is arranged in the feeding port at the top of the powder box (5); the powder feeding mechanism comprises an outer powder feeding vacuum gate valve (2), a buffer hopper (4) and an inner powder feeding vacuum gate valve (3) which are arranged in sequence from top to bottom, and vacuum feeding of the powder box (5) is achieved by alternately opening and closing the outer powder feeding vacuum gate valve (2) and the inner powder feeding vacuum gate valve (3).

5. The titanium alloy curved surface rapid prototyping device according to claim 2, characterized in that: The discharge mechanism comprises a vacuum ultrasonic vibration table (17), a discharge bin (18) and a powder collecting tube (16), wherein the discharge bin (18) is arranged at the bottom of the vacuum chamber (1), and a discharge vacuum plug valve (13) is arranged at the top of the discharge bin (18), and the discharge vacuum plug valve (13) is used for connecting or isolating the vacuum chamber (1) and the discharge bin (18); the vacuum ultrasonic vibration table (17) and the powder collecting tube (16) are arranged in the discharge bin (18) from top to bottom, and the vacuum ultrasonic vibration table (17) removes titanium alloy powder inside the porous titanium artificial tooth root implant (20) by ultrasonic vibration, and the titanium alloy powder falls into the powder collecting tube (16); a heating module is arranged in the vacuum ultrasonic vibration table (17), and the porous titanium artificial tooth root implant (20) is heated to above the recrystallization temperature by the heating module.

6. The titanium alloy curved surface rapid prototyping device according to claim 5, characterized in that: The upper part of the material drop bin (18) is connected to a pipeline (12), and the pipeline (12) is connected to a gas control system (11). The gas control system (11) introduces an inert gas into the material drop bin (18) through the pipeline (12), and the porous titanium artificial tooth root implant (20) is subjected to gradient pressurization by the inert gas, so that the grains of the porous titanium artificial tooth root implant (20) are refined.

7. The titanium alloy curved surface rapid prototyping device according to claim 2, characterized in that: The printing track (26) of the electron beam (10) emitted by the electron beam generator (9) is non-linear, and the multiple printing tracks (26) in each layer are parallel to each other and are equidistant; the directions of the printing tracks (26) in each layer are different, and the intersection nodes of each printing track (26) with the upper and lower layers do not overlap; the printed microstructure of the porous titanium artificial tooth root implant (20) has non-linear penetrating pores.

8. A forming method using the titanium alloy curved surface rapid forming device as claimed in claim 6, characterized in that: The following steps are involved: Step S1: Modeling based on the patient's mandibular 3D CT; Step S2: the powder feeding mechanism feeds the powder box (5) with vacuum, and the powder box (5) preheats the titanium alloy powder; Step S3: the quantitative powder dispenser (7) performs intermittent quantitative powder dropping, and the powder spreading device (8) pushes each quantitative powder drop of the quantitative powder dispenser (7) onto the lifting platform (21); Step S4: the electron beam generator (9) emits an electron beam (10) to the titanium alloy powder on the lifting platform (21) to perform layer-by-layer 3D printing, so as to print and shape the titanium alloy powder into a porous titanium artificial tooth root implant (20); Step S5: the lifting platform (21) rises to be flush with the bottom surface of the powder box (5), and the powder spreader (8) pushes the porous titanium artificial tooth root implant (20) into the drop bin (18), and drops it onto the vacuum ultrasonic vibration table (17); Step S6: The vacuum ultrasonic vibration table (17) uses ultrasonic vibration to remove the titanium alloy powder in the internal space of the porous titanium artificial tooth root implant (20), and heats the porous titanium artificial tooth root implant (20) to recrystallize the porous titanium artificial tooth root implant (20); Step S7: an inert gas is introduced into the material drop bin (18), and the porous titanium artificial tooth root implant (20) is subjected to gradient pressure by the inert gas to refine the grains of the porous titanium artificial tooth root implant (20), and then cooled; Step S8: taking out the porous titanium artificial tooth root implant (20) from the material bin (18) and performing surface coating treatment; Step S9: characterizing the coating of the porous titanium artificial tooth root implant (20) and determining the physical and chemical properties; Step S10: evaluating the biological function of the coating of the porous titanium artificial tooth root implant (20).

9. The molding method according to claim 8, characterized in that: The porous titanium artificial tooth root implant (20) is a porous Ti15Zr alloy; In step S8, the surface coating of the porous titanium artificial tooth root implant (20) is treated by an electrochemical method, with a graphite electrode as an anode and a porous Ti15Zr alloy as a cathode, and the process parameters are adjusted to prepare a variety of nano-coatings on the porous Ti15Zr alloy.

10. The molding method according to claim 9, characterized in that: By immersing the porous titanium artificial tooth root implant (20) in different electrochemical solution reaction cells at different depths, HA, HA-GO, HA-Ag and HA-MgO nano-coatings are prepared on the porous Ti15Zr alloy.

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