Titanium alloy curved surface rapid prototyping device and method

Abstract

The present invention belongs to the field of titanium alloy forming technology, and particularly relates to a titanium alloy curved surface rapid forming device and method. The device includes 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 electron beam generator and the powder box are arranged at the inner top of the vacuum chamber and the powder box is connected to the powder feeding mechanism, and the quantitative powder dispenser is arranged at the bottom of the powder box; the powder spreader, the lifting platform and the discharging mechanism are arranged at the bottom of the vacuum chamber in sequence, and the electron beam generator prints the titanium alloy powder in the forming mechanism into a porous titanium artificial tooth root implant; the powder spreader pushes the quantitative powder onto the forming mechanism and pushes the porous titanium artificial tooth root implant into the discharging mechanism, and the discharging mechanism performs dust removal and heat treatment on the porous titanium artificial tooth root implant. The present invention realizes precise control of the pore size and pore structure during the forming process, and the pores are interconnected and connected, which greatly improves the biocompatibility of the material.

Description

Technical Field

[0001] The present 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 orthopedic implants due to their excellent mechanical properties, biocompatibility, and corrosion resistance. To achieve permanent or semi-permanent biofixation of the implant, a porous coating is typically applied to the implant surface. However, porous coatings are typically very thin, and a high elastic modulus gradient exists between the solid substrate and the porous coating, with the solid substrate bearing nearly all the load. While porous coatings can address surface biofixation, they cannot avoid the "stress shielding" phenomenon caused by the mismatch in mechanical properties between the implant and bone tissue. This can result in minimal new bone growth into the pores, or bone atrophy around the implant with long-term use. Due to the pore structure of porous materials, the elastic modulus can be adjusted to a range that matches natural bone. Therefore, using porous materials as the entire implant can not only permanently or semi-permanently fix the implant to the bone tissue surface, but also because the mechanical properties of the implant match those of the 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 the 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 the 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 deteriorate. 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 purpose 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:

[0006] 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.

[0007] 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 fixed amount of powder pushed by the powder spreader, and when the lifting platform rises, it lifts the printed porous titanium artificial tooth root implant.

[0008] In one possible implementation, a preheater for preheating the titanium alloy powder is provided on the top of the powder box.

[0009] 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 plug valve, a buffer hopper and an inner powder feeding vacuum plug valve arranged in sequence from top to bottom, and the vacuum feeding of the powder box is achieved by alternately opening and closing the outer powder feeding vacuum plug valve and the inner powder feeding vacuum plug valve.

[0010] In one possible implementation, the discharging mechanism includes a vacuum ultrasonic vibration table, a discharge bin and a powder collecting tube, wherein the discharge bin is arranged at the bottom of the vacuum chamber, and a discharge vacuum plug-in valve is provided on the top of the discharge bin, and the discharge vacuum plug-in valve is used to connect or isolate the vacuum chamber and the discharge bin; the vacuum ultrasonic vibration table and the powder collecting tube 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 tube; 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.

[0011] In one possible implementation, the upper part of the blanking bin is connected to a pipeline, and the pipeline is connected to a gas control system. The gas control system introduces inert gas into the blanking 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.

[0012] 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.

[0013] Another aspect of the present invention provides a forming method using the titanium alloy curved surface rapid prototyping device as described above, comprising the following steps:

[0014] Step S1: Modeling based on the patient's mandibular 3D CT scan;

[0015] Step S2: The powder feeding mechanism feeds the powder into the powder box in a vacuum manner, and the powder box preheats the titanium alloy powder;

[0016] 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;

[0017] 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, thereby printing the titanium alloy powder into a porous titanium artificial tooth root implant;

[0018] 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;

[0019] Step S6: The vacuum ultrasonic vibration table uses ultrasonic vibration to remove 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;

[0020] Step S7: introducing an inert gas into the blanking 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;

[0021] Step S8: taking out the porous titanium artificial tooth root implant from the material bin and performing surface coating treatment;

[0022] Step S9: characterization of the coating and determination of the physical and chemical properties of the porous titanium artificial tooth root implant;

[0023] Step S10: evaluating the biological function of the porous titanium artificial tooth root implant coating.

[0024] In one possible implementation, the porous titanium artificial tooth root implant is a porous Ti15Zr alloy;

[0025] 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.

[0026] In one possible implementation, the porous titanium artificial tooth root implant is immersed in different electrochemical solution reaction cells at different depths to prepare HA, HA-GO, HA-Ag and HA-MgO nano-coatings on the porous Ti15Zr alloy.

[0027] 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 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.

[0028] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be 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.

[0029] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] 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:

[0031] Figure 1 This is a schematic structural diagram of a titanium alloy curved surface rapid prototyping device according to the present invention;

[0032] Figure 2 is an axonometric view of the porous titanium artificial tooth root implant of the present invention;

[0033] Figure 3 is a cross-sectional view of the porous titanium artificial tooth root implant of the present invention;

[0034] Figure 4 Schematic diagram of the printing trajectory of the electron beam generator in the present invention;

[0035] Figure 5 A side view of a three-layer printing track of an electron beam generator in the present invention;

[0036] Figure 6 It is an axonometric diagram of the three-layer printing track of the electron beam generator in the present invention;

[0037] Figure 7 This is a top view of the three-layer printing track of the electron beam generator in the present invention.

[0038] In the figure: 1-vacuum chamber, 2-external powder inlet vacuum plug valve, 3-inner powder inlet vacuum plug valve, 4-

[0039] Buffer hopper, 5-powder box, 6-preheater, 7-quantitative powder distributor, 8-powder spreader, 9-electron beam generator,

[0040] 10-electron beam, 11-gas control system, 12-pipeline, 13-discharge vacuum plug valve, 14-upper vacuum door, 15-lower vacuum door, 16-powder collection 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-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

[0041] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0042] The preferred embodiments of the present invention are described below with reference to 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.

[0043] One 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 includes a vacuum chamber 1, a powder feeding mechanism, a powder box 5, a quantitative powder dispenser 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, and the quantitative powder dispenser 7 is arranged at the bottom of the powder box 5 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 arranged at the top of the vacuum chamber 1, and the electron beam generator 9 is used to emit an electron beam 10 to the titanium alloy powder in the forming mechanism to print and form 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 dispenser 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.

[0044] See also Figure 1 As shown, in this embodiment of the present invention, a preheater 6 is installed at the top of the powder box 5 for preheating and heating the titanium alloy powder. A powder feed mechanism is located within the feed port at the top of the powder box 5. The powder feed mechanism comprises, from top to bottom, an outer powder feed vacuum valve 2, a buffer hopper 4, and an inner powder feed vacuum valve 3. Vacuum feeding of the powder box 5 is achieved by alternating the opening and closing of the outer and inner powder feed vacuum valves 2 and 3. Together, the outer and inner powder feed vacuum valves 2, 3, and buffer hopper 4 ensure that titanium powder enters the vacuum environment of the powder box 5 from the atmospheric environment, while maintaining the vacuum environment within the vacuum chamber 1. When the inner powder feed vacuum valve 3 is closed, the area surrounding the buffer hopper 4 returns to atmospheric air. When the outer powder feed vacuum valve 2 is opened, powder is manually replenished in the buffer hopper 4. When the outer powder feed vacuum valve 2 is closed, the vacuum environment within the vacuum chamber 1 is established. The inner powder inlet vacuum gate valve 3 opens, and the buffer hopper 4, driven by the vacuum direct drive motor, changes its opening from upward to downward. The titanium powder in the buffer hopper 4, guided by the lower hopper in the vacuum, precisely enters the powder box 5. The inner powder inlet vacuum gate valve 3 closes, and the buffer hopper 4 returns to its original position. This ensures that the buffer hopper 4 moves in a vacuum, preventing the nano-titanium powder from scattering.

[0045] 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.

[0046] Specifically, the electron beam generator 9 emits an electron beam 10 toward the titanium alloy powder on the lifting platform 21, first printing the substrate 22, then performing EBM forming layer by layer on the substrate 22, and printing multiple porous titanium artificial tooth root implants 20 with high throughput.

[0047] 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 discharge vacuum plug-in valve 13 is provided on the top of the discharge bin 18, and the discharge vacuum plug-in 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.

[0048] In this embodiment, the vacuum ultrasonic vibration table 17 removes nano-titanium powder using a different principle than an ultrasonic vacuum cleaner. The vacuum ultrasonic vibration table 17 removes nano-titanium powder from porous titanium artificial tooth root implants 20 by simultaneously dropping feathers and iron balls to the ground within a vacuum. This prevents the nano-titanium powder from scattering, thus preventing the operator from inhaling titanium alloy dust, which is beneficial to their health and safety. Traditional methods of blasting to remove dust from porous human implant bones are not suitable for dental implants.

[0049] Furthermore, the upper portion of the discharge bin 18 is connected to the pipeline 12, which is in turn connected to the gas control system 11. A discharge vacuum gate valve 13 isolates the vacuum ultrasonic vibration table 17 from the interior of the vacuum chamber 1. The gas control system 11 introduces inert gas into the discharge bin 18 via the pipeline 12. This inert gas applies a gradient pressurization to the porous titanium artificial tooth root implant 20, thereby refining the porous titanium artificial tooth root implant 20. The gradient pressurization strategy was developed using fluid and solid conjugate thermodynamics simulation and crystallization process simulation software, and was subsequently determined through experimental verification.

[0050] The gas control system 11 restores the pressure in the discharge 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 cylinder 16 is taken out from the lower vacuum door 15 .

[0051] See also Figure 2 、 Figure 3 As shown, in this embodiment of the present invention, the porous titanium artificial tooth root implant 20 includes a tooth root implant body 23. The tooth root implant body 23 is a hollow cone with internal and external threads 25 and 24, respectively, on its inner and outer surfaces. The external threads 24 are used for fixation to the mandible, while the internal threads 25 are used for locking with the abutment and crown. Because each person's mandible is different, the multiple porous titanium artificial tooth root implants 20 printed on the substrate 22 are unique, and their specific size and length are customized based on the patient's mandible 3D CT model.

[0052] 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 directions of the printing trajectories 26 of each layer are different, forming a grid shape, and each printing trajectory 26 does not overlap with the intersection nodes of the upper and lower layers.

[0053] Specifically, taking a three-layer printing trajectory as an example, the horizontal projections of the printed connection nodes between the first-layer printing trajectory 27, the second-layer printing trajectory 28, and the third-layer printing trajectory 29 do not overlap. Therefore, the printed microstructure of the porous titanium artificial tooth root implant 20 features non-linear pores, meaning that all pores in each layer are spatially interconnected vertically. In other words, a single printing trajectory 26 does not overlap with the printed nodes of the lower and upper layers. This layout is suitable for producing anisotropy in the tooth in both the compressive and other directions.

[0054] See also Figure 7 As shown, in the embodiment of the present invention, non-linear pine needles 31 are contained outside the three-dimensional boundary 30 of the porous titanium artificial tooth root implant 20. The non-linear pine needles 31 can effectively penetrate into the mandibular bone, thereby enhancing the fixation effect.

[0055] In this embodiment, the material of the porous titanium artificial tooth root implant 20 is preferably Ti15Zr alloy, with a compressive strength of ≥100 MPa, a porosity of ≥30%, and an elastic modulus of ≤20 GPa.

[0056] 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. It can achieve precise control of pore size and pore structure, and 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.

[0057] Based on the above design concept, another embodiment of the present invention provides a forming method using the titanium alloy curved surface rapid prototyping device in the above embodiment, see Figures 1 to 7 As shown, the molding method includes the following steps:

[0058] Step S1: Modeling based on the patient's mandibular 3D CT scan;

[0059] Based on the patient's mandibular 3D model, we customize and design multiple 3D models of the tissues to be implanted. The 3D models of the tissues to be implanted are then sliced ​​and imported into a 3D printer.

[0060] Step S2: The powder feeding mechanism feeds the powder into the powder box 5 in a vacuum manner, and the powder box 5 preheats the titanium alloy powder;

[0061] Specifically, the titanium alloy powder is prepared by ultrasonic gas atomization to obtain a powder with a diameter of 40-70 μm;

[0062] 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;

[0063] Step S4: The electron beam generator 9 emits an electron beam 10 onto the titanium alloy powder on the lifting platform 21 to perform layer-by-layer 3D printing, thereby printing and molding the titanium alloy powder into a porous titanium artificial tooth root implant 20;

[0064] 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;

[0065] Step S6: The vacuum ultrasonic vibration table 17 uses ultrasonic vibration to remove titanium alloy powder in the internal space of the porous titanium artificial tooth root implant 20, and at the same time heats the porous titanium artificial tooth root implant 20 to above the recrystallization temperature to recrystallize the porous titanium artificial tooth root implant 20;

[0066] Step S7: Inert gas is introduced into the blanking 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;

[0067] Step S8: taking out the porous titanium artificial tooth root implant 20 from the blanking bin 18 and performing surface coating treatment;

[0068] Step S9: characterizing the coating and measuring the physical and chemical properties of the porous titanium artificial tooth root implant 20;

[0069] Step S10: Evaluating the biological function of the coating of the porous titanium artificial tooth root implant 20 .

[0070] In this embodiment, the porous titanium artificial tooth root implant 20 is a porous Ti15Zr alloy.

[0071] 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.

[0072] Specifically, the porous titanium artificial tooth root implant 20 is immersed in different electrochemical solution reaction tanks at different depths, such as the depth of penetration of HA is different from the depth of penetration of GO. HA, HA-GO, HA-Ag, and HA-MgO nanocoatings are prepared on the porous Ti15Zr alloy.

[0073] 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.

[0074] 1) The microstructure, surface morphology, and surface roughness of the porous Ti15Zr alloy and coating were observed using scanning electron microscopy and atomic force microscopy. The effects of process parameters on the coating morphology were analyzed. The elemental composition of the material surface was qualitatively analyzed using X-ray photoelectron spectroscopy.

[0075] 2) An electrochemical workstation and a multifunctional material surface performance tester were used to analyze the corrosion resistance, adhesion, and mechanical strength of the coating. The solid-liquid contact angle method was used to analyze the hydrophilic and hydrophobic properties of the coating.

[0076] 3) The antibacterial activity of the coating was tested using Escherichia coli and Staphylococcus aureus. The physiological stability of the coating was investigated by measuring the absorbance of various ions in the immersion solution using a microplate reader.

[0077] In step S10, including but not limited to, performing cell compatibility evaluation on the implant using existing technology, in compliance with the GB / T16886 series of standards for biological evaluation of biomedical materials in my country.

[0078] 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 the precise preparation of porous Ti15Zr alloy by EBM were explored.

[0079] 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.

[0080] Preparation methods of porous titanium medical implant tooth root bone screws other than electron beam powder bed and laser powder bed cannot be compared with preparation methods of porous titanium medical implant bone screws by electron beam powder bed and laser powder bed due to the element contamination problem of curved forming mold and the problem of porous shape control. The electron beam powder bed of the present invention has the key point of economic industrialization in preparing porous titanium artificial tooth root implants. The commercial electron beam powder bed is 3kw, which has the advantages of high power and high forming efficiency compared to 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 be parallel, and can achieve continuous production.

[0081] The present invention provides a method for rapid prototyping of titanium alloy curved surfaces, which can achieve precise control of pore size and pore structure, and the pores are interconnected and connected, 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. Due to the high temperature during the melting process of titanium alloy powder, the grains in the material will grow, and the solid solubility will also change. 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 controllable temperature reduction gradient measure of high-pressure nitrogen 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.

[0082] 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 floating, thereby preventing the operator from inhaling titanium alloy dust, which is beneficial to the health and safety of the operator.

[0083] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

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); The forming mechanism comprises a forming cylinder (19) and a lifting platform (21), wherein the lifting platform (21) is slidably disposed in the forming cylinder (19) up and down; when the lifting platform (21) is in a descending position, it receives a fixed amount of powder pushed by the powder spreader (8); and when the lifting platform (21) rises, it lifts the printed porous titanium artificial tooth root implant (20); A preheater (6) for preheating titanium alloy powder is provided on the top of the powder box (5); 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 provided 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 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; The upper part of the material drop bin (18) is connected to a pipeline (12), the pipeline (12) is connected to a gas control system (11), and 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; 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; The porous titanium artificial tooth root implant (20) comprises a tooth root implant body (23), which is a hollow conical body and has internal threads (25) and external threads (24) on its inner and outer surfaces, respectively. The external threads (24) are used for fixing to the mandible, and the internal threads (25) are used for locking to the base and the crown. The porous titanium artificial tooth root implant (20) contains non-linear pine needles (31) outside the three-dimensional boundary (30), and the non-linear pine needles (31) can effectively penetrate into the mandibular bone.

2. The titanium alloy curved surface rapid prototyping device according to claim 1, 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).

3. A forming method using the titanium alloy curved surface rapid forming device as claimed in claim 1, 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).

4. The molding method according to claim 3, 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.

5. The molding method according to claim 4, 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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