Novel TPMS porous structure interbody fusion cage

Abstract

The invention provides a novel TPMS porous structure interbody fusion cage, and relates to the technical field of medical materials. The interbody fusion cage is designed by using a porous frame structure with different unit cell sizes and porosities, so that the biocompatibility of the interbody fusion cage is enhanced, the interbody fusion cage has higher mechanical properties, large static compression load and low elastic modulus, the elastic modulus is closer to that of human cortical bones, the stability of an implant in the early stage of osseointegration is improved, and the interbody fusion cage is suitable for being used in the field of osteosynthesis. Under the same porosity, the elastic modulus is lower, and the comprehensive performance is excellent.

Description

Technical Field

[0001] The invention relates to the technical field of medical materials, and in particular to a novel TPMS porous structure intervertebral fusion device. Background Art

[0002] Intervertebral fusion is one of the classic surgical methods for treating degenerative spinal diseases. Traditional intervertebral fusion techniques mostly use autologous bone or artificial bone transplantation, but they often cause complications in the transplant area and even lead to adverse reactions such as instability in the fusion segment. Therefore, the existing technology proposes the TPMS lattice structure, which is widely present in nature. The three-periodic minimal surface (TPMS) is a special surface that repeats periodically in three dimensions in space and has an average curvature of zero. This type of structure has a smooth surface and highly connected holes. The overall structure can be accurately controlled by implicit functions. It is an excellent solution for designing and modeling porous structures, and was initially widely used in architecture.

[0003] Recent studies have shown that the curvature of the surface where cells are located is an important factor in determining the rate of tissue regeneration, and the rate of tissue regeneration increases with the increase of curvature. Compared with convex and flat surfaces, tissue regeneration progresses faster on concave surfaces. Therefore, when designing a porous bone scaffold structure, it is particularly important to construct a relatively large curvature configuration, which also provides theoretical support for the biochemical application of TPMS lattice structures.

[0004] The TPMS lattice structure has significant advantages over previous structures. First, its average curvature is zero, which is closer to the average curvature of trabecular bone, and is therefore more conducive to early bone integration and even mid- to late-stage bone ingrowth. Second, the structure has a higher specific surface area, which can provide more space for cell adhesion, migration, proliferation, and differentiation. More importantly, compared with the traditional truss lattice structure, the TPMS porous structure can adjust the elastic modulus of the scaffold in a wider range, so that a modulus value similar to that of human bone can be designed, thereby enhancing the matching effect of the bone-scaffold interface.

[0005] At the same time, sufficient mechanical properties are also an important parameter that an intervertebral fusion cage should have. This structure has unique self-supporting characteristics, good porosity, permeability, and excellent mechanical properties. More importantly, at the same porosity, it has a lower elastic modulus, which can effectively reduce stress shielding and bone absorption, and is a more ideal model of an intervertebral fusion cage with a porous structure. Summary of the invention

[0006] The purpose of the present invention is to provide a novel TPMS porous structure intervertebral fusion device in view of the deficiencies of the prior art. The present invention uses a porous framework structure with different unit cell sizes and porosities to design an intervertebral fusion device, which not only enhances its biocompatibility, but also shows strong mechanical properties, improves the stability of the implant in the early and middle and late stages of bone integration, and has a lower elastic modulus at the same porosity, and has excellent comprehensive performance.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] A novel TPMS porous structure intervertebral fusion device, the basic structure of the TPMS porous structure intervertebral fusion device is a gyro (Gyroid) structure, and its basic function equation is:

[0009] sin X cos Y+sin Y cos Z+sin Z cos X=C;

[0010] Where X = 2απx, Y = 2βπy, Z = 2γπz; α, β, γ are constants related to the unit cell size in the x, y and z directions, respectively, and C is the value.

[0011] Furthermore, the framework includes two parameters: unit cell size and porosity; the unit cell size is 1-3 mm, preferably any one of 1 mm, 1.5 mm, 2 mm, 2.5 mm, and 3 mm; the porosity is 50-70%, preferably any one of 50%, 60%, and 70%.

[0012] Furthermore, the printing material of the TPMS porous structure intervertebral fusion device is Ti-6Al-4V medical titanium alloy.

[0013] Furthermore, the frame of the TPMS porous structure intervertebral fusion device is formed by 3D printing, and the interior of the fusion device is a porous structure composed of three-dimensional grids.

[0014] Furthermore, the pore size of the TPMS porous structure intervertebral fusion device is in the range of 50-640 μm; the height L1 of the TPMS porous structure intervertebral fusion device is 4-17 mm; the height L2 of the bone grafting area inside the TPMS porous structure intervertebral fusion device is 2-9 mm; the length L3 of the tail bone grafting area inside the TPMS porous structure intervertebral fusion device is 3-9 mm; the length L4 of the front bone grafting area inside the TPMS porous structure intervertebral fusion device is 3-9 mm; the length L of the adjacent barb structures above and below the TPMS porous structure intervertebral fusion device is 1. 5 is 1-4mm; the length L6 of the bone grafting area at the top of the TPMS porous structure intervertebral fusion device is 10-16mm; the width L7 of the bone grafting area at the top of the TPMS porous structure intervertebral fusion device is 3-7mm; the width L8 of the barb structure at the top of the TPMS porous structure intervertebral fusion device is 1.7-4mm; the length H of the TPMS porous structure intervertebral fusion device is 20-30mm; the width W of the TPMS porous structure intervertebral fusion device is 7-13mm; the diameter D of the connecting rod hole at the tail end of the TPMS porous structure intervertebral fusion device is 2-5mm.

[0015] The present invention also provides a method for preparing a TPMS porous structure intervertebral fusion device, comprising the following steps:

[0016] (1) Using the aforementioned basic function equation, the intervertebral fusion cage model is obtained, and the 3D model is placed at a suitable printing angle through STL processing software, and the export support is generated;

[0017] (2) Slice the model and support;

[0018] (3) Adjust the printing parameters, fill the printing chamber with protective gas, import the printing file and start printing;

[0019] (4) After printing is completed, the metal powder is cleaned and recovered, and the printed workpiece is sandblasted, vibrated and wire-cut, and ultrasonically cleaned before heat treatment.

[0020] Furthermore, in step (3), the printing parameters are: printing spot 20-100 μm, filling scanning power 110-250 W, printing layer thickness 0.01-0.1 mm, filling scanning speed 0.1-2 m / s, contour scanning speed 0.1-2 m / s, contour scanning power 50-150 W, scanning spacing 0.05-0.5 mm.

[0021] Preferably, the printing parameters are: printing spot 60 μm, filling scanning power 181 W, printing layer thickness 0.05 mm, filling scanning speed 0.89 m / s, contour scanning speed 0.89 m / s, contour scanning power 146 W, and scanning spacing 0.08 mm.

[0022] Furthermore, in step (4), during the process of cleaning and recovering the metal powder, the internal support is easy to store the powder, and the powder on the lifting platform is first recovered and then recovered in the cabin, and the powder is blown by tilting.

[0023] Furthermore, in step (4), the sandblasting includes sandblasting with corundum and pure titanium. Before sandblasting with corundum, the workpiece is ensured to be clean and dry to prevent the protective coating from being sprayed. The solid part is sandblasted and then polished. The sandblasting is repeated to ensure that there are no protrusions on the support part; then pure titanium powder is repeatedly sprayed to ensure that the surface is smooth and bright; the sandblasting conditions are: distance: 100mm-150mm, air pressure 0.6MPa, angle 45°, time: 20s.

[0024] Furthermore, in step (4), during the powder vibrating process, the substrate is vibrated at a high frequency to clean out residual powder and corundum.

[0025] Furthermore, in step (4), the wire cutting process uses the smallest thread as the cutting direction.

[0026] Furthermore, in step (4), detergent is added during the ultrasonic cleaning process, the cleaning temperature is 30-60°C, and the cleaning is repeated until no impurities and oil stains are washed out.

[0027] Furthermore, in step (4), the heat treatment is carried out by staged heating: first heating to 400-500°C, keeping warm for 0.5-1h, then heating to 920-930°C, keeping warm for 0.5-1h, and the pressure is maintained at 110-120MPa throughout the process.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The TPMS porous structure intervertebral fusion device provided by the present invention adjusts the unit cell size and porosity so that the pore size of the obtained TPMS porous structure intervertebral fusion device is controlled within a certain range. Such a structural design not only enhances its biocompatibility, but also shows strong mechanical properties, meets the strength requirements of the plants in the human body, has excellent comprehensive performance, and has a better bone integration effect.

[0030] 2. The TPMS porous structure intervertebral fusion device provided by the present invention has a high load, and the maximum load is much higher than the maximum load that the human body can withstand, and can provide better anti-compression performance.

[0031] 3. The TPMS porous structure intervertebral fusion device provided by the present invention has a low elastic modulus, which is closer to the elastic modulus of human cortical bone, is more conducive to early bone ingrowth and mid-to-late implant stability, and provides excellent mechanical properties for achieving better bone integration effect.

[0032] 4. The TPMS porous structure intervertebral fusion device provided by the present invention has good biocompatibility and can promote cell proliferation while satisfying the low elastic modulus of the support.

[0033] 5. The TPMS porous structure intervertebral fusion device of the present invention is heat-treated after printing. By controlling the heat treatment conditions, it has better mechanical properties and the ability to promote cell proliferation. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a solid diagram of the TPMS porous structure intervertebral fusion device of the present invention; A represents the neutral position; B represents the horizontal position.

[0035] Figure 2 It is a schematic diagram of the structure of the TPMS porous structure intervertebral fusion device of the present invention; A represents the front surface of the fusion device; B represents the side surface of the fusion device; and C represents the bottom surface of the fusion device.

[0036] Figure 3 It is a statistical diagram of cell proliferation at different porosities and different heat treatments of the TPMS porous structure intervertebral fusion device of the present invention (the single cell size in the figure is 1.0 mm); A represents cell proliferation at different porosities; B represents cell proliferation at different heat treatment conditions.

[0037] Figure 4 The figure is a statistical diagram of the proliferation of cells inoculated in the TPMS porous intervertebral fusion device of the present invention. A represents the proliferation of cells of different cell sizes when the porosity is 50; B represents the proliferation of cells of different cell sizes when the porosity is 60; C represents the proliferation of cells of different cell sizes when the porosity is 70. DETAILED DESCRIPTION

[0038] The following non-limiting examples can enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way. The following content is only an exemplary description of the scope of the present invention, and those skilled in the art can make various changes and modifications to the invention of the present invention based on the disclosed content, and they should also fall within the scope of the present invention.

[0039] The present invention is further described below by way of specific examples. Unless otherwise specified, the various chemical reagents used in the examples of the present invention are obtained through conventional commercial channels.

[0040] Example 1

[0041] This embodiment provides a method for preparing a TPMS porous structure intervertebral fusion device, comprising the following steps:

[0042] (1) Using the basic function equation, adjusting the porosity and unit cell size, the intervertebral fusion cage model is exported as an STL file. Using the STL processing software, the 3D model is placed at a suitable printing angle and the export support is generated;

[0043] The basic function equation is: sin X cos Y + sin Y cos Z + sin Z cos X = C, where X = 2απx, Y = 2βπy, Z = 2γπz; α, β, γ are constants related to the unit cell size in the x, y and z directions respectively;

[0044] (2) Slice the model and support;

[0045] (3) adjusting the printing parameters, filling the printing chamber with protective gas, importing the printing file, and printing with Ti-6Al-4V medical titanium alloy as the printing material;

[0046] The Ti-6Al-4V medical titanium alloy contains 4.03% V and 6.01% Al;

[0047] The printing parameters are: printing spot 60 μm, filling scanning power 181 W, printing layer thickness 0.05 mm, filling scanning speed 0.89 m / s, contour scanning speed 0.89 m / s, contour scanning power 146 W, scanning spacing 0.08 mm;

[0048] (4) After printing, clean and recycle the metal powder, sandblast the printed workpiece with diamond and pure titanium, then vibrate the powder and cut it in parallel, with the smallest thread as the cutting direction, and perform ultrasonic cleaning. During the cleaning process, add detergent for cleaning at a temperature of 30°C, and wash repeatedly until no impurities or oil stains are washed out; finally, perform heat treatment under the following conditions: first heat up to 500°C, keep warm for 0.5h, then heat up to 930°C, and keep warm for 1h. Maintain 110Mpa throughout the process to obtain the TPMS porous structure intervertebral fusion device, as shown in the solid figure. Figure 1 As shown, the structural diagram is as follows Figure 2 shown.

[0049] By adjusting the porosity and unit cell size parameters, different TPMS porous structure intervertebral fusion devices can be obtained, such as:

[0050] TPMS1-5: Porosity 50%

[0051] TPMS1: Porosity 50%, unit cell size 1mm

[0052] sin(2πx)cos(2πy)+sin(2πy)cos(2πz)+sin(2πz)cos(2πx)=0.766;

[0053] TPMS2: Porosity 50%, unit cell size 1.5mm

[0054] sin(4 / 3πx)cos(4 / 3πy)+sin(4 / 3πy)cos(4 / 3πz)+sin(4 / 3πz)cos(4 / 3πx)=0.766;

[0055] TPMS3: Porosity 50%, unit cell size 2mm

[0056] sin(πx)cos(πy)+sin(πy)cos(πz)+sin(πz)cos(πx)=0.766;

[0057] TPMS4: Porosity 50%, unit cell size 2.5mm

[0058] sin(4 / 5πx)cos(4 / 5πy)+sin(4 / 5πy)cos(4 / 5πz)+sin(4 / 5πz)cos(4 / 5πx)=0.766;

[0059] TPMS5: Porosity 50%, unit cell size 3mm

[0060] sin(2 / 3πx)cos(2 / 3πy)+sin(2 / 3πy)cos(2 / 3πz)+sin(2 / 3πz)cos(2 / 3πx)=0.766;

[0061] TPMS6-10: Porosity 60%

[0062] TPMS6: Porosity 60%, unit cell size 1mm

[0063] sin(2πx)cos(2πy)+sin(2πy)cos(2πz)+sin(2πz)cos(2πx)=0.623;

[0064] TPMS7: Porosity 60%, unit cell size 1.5mm

[0065] sin(4 / 3πx)cos(4 / 3πy)+sin(4 / 3πy)cos(4 / 3πz)+sin(4 / 3πz)cos(4 / 3πx)=0.623;

[0066] TPMS8: Porosity 60%, unit cell size 2mm

[0067] sin(πx)cos(πy)+sin(πy)cos(πz)+sin(πz)cos(πx)=0.623;

[0068] TPMS9: Porosity 60%, unit cell size 2.5mm

[0069] sin(4 / 5πx)cos(4 / 5πy)+sin(4 / 5πy)cos(4 / 5πz)+sin(4 / 5πz)cos(4 / 5πx)=0.623;

[0070] TPMS10: Porosity 60%, unit cell size 3mm

[0071] sin(2 / 3πx)cos(2 / 3πy)+sin(2 / 3πy)cos(2 / 3πz)+sin(2 / 3πz)cos(2 / 3πx)=0.623;

[0072] TPMS11-15: Porosity 70%

[0073] TPMS11: Porosity 70%, unit cell size 1mm

[0074] sin(2πx)cos(2πy)+sin(2πy)cos(2πz)+sin(2πz)cos(2πx)=0.48;

[0075] TPMS12: Porosity 70%, unit cell size 1.5mm

[0076] sin(4 / 3πx)cos(4 / 3πy)+sin(4 / 3πy)cos(4 / 3πz)+sin(4 / 3πz)cos(4 / 3πx)=0.48;

[0077] TPMS13: Porosity 70%, unit cell size 2mm

[0078] sin(πx)cos(πy)+sin(πy)cos(πz)+sin(πz)cos(πx)=0.48;

[0079] TPMS14: Porosity 70%, unit cell size 2.5mm

[0080] sin(4 / 5πx)cos(4 / 5πy)+sin(4 / 5πy)cos(4 / 5πz)+sin(4 / 5πz)cos(4 / 5πx)=0.48;

[0081] TPMS15: Porosity 70%, unit cell size 3mm

[0082] sin(2 / 3πx)cos(2 / 3πy)+sin(2 / 3πy)cos(2 / 3πz)+sin(2 / 3πz)cos(2 / 3πx)=0.48;

[0083] Embodiment 2-9

[0084] The difference from Example 1 is that the heat treatment conditions are different. Taking the TPMS porous structure intervertebral fusion device with a porosity of 60% and a unit cell size of 1 mm as an example, the heat treatment conditions are shown in Table 1 below.

[0085] Table 1

[0086]

[0087]

[0088] Test Example 1

[0089] The basic unit cell shape of the TPMS porous structure intervertebral fusion device provided by the present invention is a gyro shape (such as Figure 3 As shown in Table 2, the porosity and unit cell size parameters are adjusted, and the thickness and pore size of the TPMS porous structure intervertebral fusion device are obtained.

[0090] Table 2

[0091] sample Porosity (%) Unit cell size (mm) Thickness(mm) Pore ​​size (μm) TPMS1 50 1 1 50-70 TPMS2 50 1.5 1.5 70-90 TPMS3 50 2 2 100-120 TPMS4 50 2.5 2.5 120-140 TPMS5 50 3 3 180-200 TPMS6 60 1 1 100-110 TPMS7 60 1.5 1.5 140-160 TPMS8 60 2 2 210-230 TPMS9 60 2.5 2.5 330-360 TPMS10 60 3 3 460-490 TPMS11 70 1 1 200-220 TPMS12 70 1.5 1.5 300-320 TPMS13 70 2 2 420-430 TPMS14 70 2.5 2.5 510-530 TPMS15 70 3 3 620-640

[0092] Test Example 2

[0093] The TPMS porous intervertebral fusion cage obtained above was subjected to a quasi-static compression test using a universal testing machine (MTS 809, USA) with a loading pressure of 100 kN. Three repeated samples of each type were tested to ensure the reliability of the results. The compression force and displacement of the stent were recorded during the compression test, and the load-displacement curve was plotted. The test results are shown in Table 2 below.

[0094] Table 2

[0095] sample Maximum load (N) Elastic modulus (Gpa) TPMS1 32562.08 16 TPMS2 33545.75 14 TPMS3 30478.49 12 TPMS4 29498.61 10.9 TPMS5 28368.52 10.6 TPMS6 42562.08 22 TPMS7 36879.45 18 TPMS8 32478.59 16.2 TPMS9 30498.61 13.6 TPMS10 29968.52 10.7 TPMS11 34875.62 15.6 TPMS12 31623.68 12.7 TPMS13 29623.42 11.4 TPMS14 31478.16 12.3 TPMS15 29769.17 10.9 Comparative Example 1 20216.70 9.7 Comparative Example 2 10628.11 7.9 Comparative Example 3 18687.12 8.3 Comparative Example 4 22418.20 9.2 Comparative Example 5 32573.83 16.2 Comparative Example 6 26478.10 9.6 Comparative Example 7 18972.42 8.9 Comparative Example 8 12314.61 8.6

[0096] The results showed that the maximum load of TPMS6 was 42562.08N and the elastic modulus was 22GPa. The maximum load was much higher than the maximum load that the human body could withstand, and it fully met the requirements for long-term load-bearing implants. The elastic modulus was closer to the 10-30GPa of human cortical bone, which was more conducive to early bone ingrowth and mid-to-late implant stability, and provided excellent mechanical properties for achieving better bone integration.

[0097] Test Example 3

[0098] After the cells were inoculated into the TPMS porous intervertebral fusion cage, the proliferation of cells was detected by CCK-8 method and flow cytometry analysis at 1, 4, and 7 days. Among them, the solid Ti-6Al-4V alloy plate of the same volume was set as the NC group as the control group.

[0099] The specific experimental steps are as follows: (1) Mg-63 cells in the logarithmic growth phase were prepared into a cell suspension and the cells were counted; (2) the counted cells were diluted to 2×10 4 cells / 500 μL concentration; (3) take three new 24-well plates, mark them as 1d, 4d, and 7d (i.e., the test date), place a fusion device in each well plate, and set up three parallel samples for each; (4) drop 500 μL of the prepared cell suspension into each well to complete the cell inoculation; (5) place the above well plates in a cell culture incubator at 37°C and 5% CO2 concentration, and change the medium every two days; (6) take out the cell culture plate on the test date and place it in a sterilized and well-ventilated clean bench. Rinse each sample twice with PBS solution to remove untouched cells, then move it to a new 24-well plate, add 500 μL of new complete culture medium, 10% The CCK-8 solution was thoroughly mixed and placed in a cell culture incubator at 37°C and 5% CO2 for 4 h; (7) 100 μL of the mixture was aspirated from each well and dropped into a 96-well plate, and the absorbance was measured at 450 nm using an ELISA reader; (8) The data were exported and analyzed and plotted.

[0100] The results are as follows Figure 4 The results showed that after 1-7 days of culture, the ability of the fusion device obtained in any experimental group to promote cell proliferation was better than that in the control group, which indicated that the fusion device obtained in the present invention had the ability to promote cell proliferation.

[0101] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A novel TPMS porous structure intervertebral fusion cage, characterized in that: It includes a frame and a cross-linking rod; the basic structure of the TPMS porous structure intervertebral fusion device is a gyroscopic structure, and its basic function equation is: sin X cos Y+sin Y cos Z+sin Z cos X=C; Wherein, X = 2απx, Y = 2βπy, Z = 2γπz; α, β, γ are constants related to the unit cell size in the x, y and z directions, respectively, and C represents a constant related to the porosity.

2. The TPMS porous structure intervertebral fusion cage according to claim 1, characterized in that: The framework includes two parameters: unit cell size and porosity; the unit cell size is 1-3 mm; and the porosity is 50-70%.

3. The TPMS porous structure intervertebral fusion cage according to claim 1, characterized in that: The printing material of the TPMS porous structure intervertebral fusion device is Ti-6Al-4V medical titanium alloy.

4. The TPMS porous structure intervertebral fusion cage according to claim 1, characterized in that: The frame structure of the TPMS porous structure intervertebral fusion device is formed by 3D printing, and the interior of the fusion device is a porous structure composed of three-dimensional grids.

5. The TPMS porous structure intervertebral fusion cage according to claim 1, characterized in that: The TPMS porous structure intervertebral fusion device has an aperture size in the range of 50-6400 μm, a height L1 of 4-17 mm, an internal bone graft area height L2 of 2-9 mm, an internal tail bone graft area length L3 of 3-9 mm, an internal front bone graft area length L4 of 3-9 mm, an upper and lower adjacent barb structure length L5 of 1-4 mm, a top bone graft area length L6 of 10-16 mm, a top bone graft area width L7 of 3-7 mm, a top barb structure width L8 of 1.7-4 mm, a length H of 20-30 mm, a width W of 7-13 mm, and a tail connecting rod hole diameter D of 2-5 mm.

6. The method for preparing the TPMS porous structure intervertebral fusion device according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Using the basic function equation, the intervertebral fusion cage model is obtained, exported as an STL file, imported into the magics software, and processed before printing. The model is placed in the pre-printing position and the STL file is exported; (2) Use SoloSlicer to import the STL file for slicing, obtain the slice file, then open it with SoloControl, layout it according to the printing position, and save the print file for printing; (3) Adjust the printing parameters, fill the printing chamber with protective gas, import the printing file and start printing; (4) After printing is completed, the metal powder is cleaned and recovered, and the printed workpiece is sandblasted, vibrated and wire-cut, and ultrasonically cleaned before heat treatment.

7. The preparation method according to claim 6, characterized in that: In step (3), the printing parameters are: printing spot 20-100μm, filling scanning power 110-250W, printing layer thickness 0.01-0.1mm, filling scanning speed 0.1-2m / s, contour scanning speed 0.1-2m / s, contour scanning power 50-150W, scanning spacing 0.05-0.5mm; the preferred printing parameters are: printing spot 60μm, filling scanning power 181W, printing layer thickness 0.05mm, filling scanning speed 0.89m / s, contour scanning speed 0.89m / s, contour scanning power 146W, scanning spacing 0.08mm.

8. The preparation method according to claim 6, characterized in that: In step (4), during the process of cleaning and recovering the metal powder, the internal support is easy to store the powder, and the powder is first recovered on the lifting platform and then recovered in the cabin, using the side tilt to blow the powder.

9. The preparation method according to claim 6, characterized in that: In step (4), the sandblasting process includes sandblasting with diamond sand and / or pure titanium.

10. The preparation method according to claim 6, characterized in that: In step (4), the heat treatment is carried out by staged heating: first heating to 400-500°C, keeping warm for 0.5-1h, then heating to 900-1000°C, keeping warm for 0.5-1h, and the pressure is maintained at 110-120MPa throughout the process.

Images