CN111975001B - Laser selective area preparation method of grading porous tantalum implant and implant - Google Patents

Abstract

The invention discloses a preparation method of a laser selective area of a grading porous tantalum implant and the implant, wherein the method comprises the following steps: in the selective laser melting and forming process, under the laser radiation, the spherical tantalum powder is melted, the hydride of the nano tantalum decomposes hydrogen at high temperature, and the hydrogen explodes and overflows under the action of high temperature and high pressure to form a first-stage porous structure on the surface of the formed tantalum; because a gap is formed between the SLM forming melting channel and the melting channel, an included angle of 30-90 degrees is formed between the current layer melting channel and the next layer melting channel, and thus a second-stage porous structure is formed; the spherical tantalum powder is melted and solidified to form a third-stage porous structure and a fourth-stage porous structure which are customized by CAD design software. The total four-level porous structure forms a multi-level cross-scale macro-micro integrated multi-level porous tantalum implant with a cross-level nano scale, a micro-scale, a millimeter scale and the like. The invention widens the tiny forming capacity of the SLM (selective laser melting) by decomposing the grading structure generated by hydrogen explosion overflow, and enhances the forming capacity of porous tantalum formed by selective laser melting.

Description

A kind of laser selective preparation method of enhanced porous tantalum implant and implant

technical field

The invention belongs to the technical field of manufacturing of augmented materials, and in particular relates to a laser selective preparation method of an enhanced porous tantalum implant and an implant.

Background technique

Laser selective melting molding technology is already a widely used and mature metal additive manufacturing technology. This technology uses the laser as the heat source, focuses the laser beam on the metal powder on the forming plane through the control of the precise optical scanning system, and moves the laser focus at high speed according to the predetermined path, so that the metal powder scanned on the forming plane melts rapidly After that, it is rapidly cooled and solidified, and three-dimensional solid metal structural parts are finally processed by scanning the cross-sectional area layer by layer and layer by layer stacking. Laser selective melting molding technology breaks through the limitation of traditional machining technology on the shape of parts in principle, and is widely used in customized personalized implants in the medical field, especially in porous structure implants. In terms of implants, titanium alloys and cobalt-chromium alloys are also widely used, and the 3D printing technology of tantalum alloy implants has gradually gained popularity. The method of preparing porous tantalum by 3D printing has been proposed.

However, it is undeniable that there are still some problems in 3D printing tantalum implants. For example, electron beam forming of tantalum can ensure no pollution and no impurities. However, electron beam forming is relatively coarse, and the precision and fine structure are limited. Fine and high precision, however, only porous structures above 300 microns can be prepared, and the finer structures are limited, and cannot match the microstructure of the real trabecular bone below 100 microns, which is not conducive to the growth and combination of bone cells, and the atmosphere environment is unavoidable The introduction of oxygen increases the oxygen content. When the powder is recycled for many times, the oxygen content of the powder will continue to increase, resulting in changes in related properties.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art, to upgrade the laser selective preparation method and implant of porous tantalum implants, and to solve the problem that laser selective melting cannot form a microstructure below 100 microns to match the real trabecular bone structure. , and the problem that the oxygen content of the powder will increase during long-term use.

In order to achieve the above object, the present invention adopts the following technical solutions:

A method for preparing an enhanced porous tantalum implant by laser selection provided by the present invention comprises the following steps:

Prepare spherical tantalum powder and nano-tantalum hydride, mix 5-30 μm spherical tantalum powder with 1-10 nanometer nano-tantalum hydride, and use high-speed ball milling and homogeneous compounding to assemble and bond the nano-tantalum hydride on the spherical Tantalum powder surface for surface-adhesive assembly;

Carry out the design of the third-level porous structure and the fourth-level porous structure, and carry out data processing and import it into a laser selective melting molding system, and use the spherical tantalum powder to which the nano-tantalum hydride has been adhered as the molding material. The third-level porous structure is a porous structure of 100-500 μm level, and the fourth-level porous structure is a porous structure of 1-10 mm;

In the process of laser selective melting and forming, under the action of laser radiation with a spot size of 50-100 μm, the spherical tantalum powder with a thickness of 20-50 μm is melted according to the set scanning speed to form a single melt channel. Decompose hydrogen, the hydrogen bursts and overflows under the action of high temperature and high pressure, and a micro-nano structure is formed on the surface of the formed tantalum, which is the first-level porous structure. porous structure;

According to the laser process parameters, the scanning spacing of 0.08-0.20mm is adopted to form a gap between the melt channel and the melt channel. At the same time, the scanning direction of the current layer and the scanning direction of the next layer form a certain angle, and the layer thickness is 20-50μm Thereby, a second-level porous structure is constructed, and this hierarchical porous structure is mostly micron-level, 10-80 micron-level porous structure;

Combined with the CAD design of SLM forming customized multi-level porous structures, such as the third-level and fourth-level porous structures, this part is mostly model data designed from CAD, and most of the third-level structures are 100-500 micron level porous structure Structure; the porous structure of the fourth level is mostly 1mm-10mm porous structure, thus forming a multi-level porous structure;

The above-mentioned four-level porous structure forms a multi-level porous tantalum implant that integrates multi-level macro-micro scales of micro-nano-scale, micro-scale and millimeter-scale.

As a preferred technical solution, the third-level porous structure and the fourth-level porous structure are designed through three-dimensional CAD design software.

As a preferred technical solution, in the process of laser selective melting and forming, the laser power is 300-500W, the scanning speed is 400-1000mm/s, the layer thickness is 20-50μm, and the scanning distance is between 0.08-0.2mm. The preheating requirement for forming is above 200 degrees Celsius.

As a preferred technical solution, the first-level porous structure is specifically:

The first-level porous structure forms micro-blasting heterogeneous micro-nano pores due to the hydrogen overflow in tantalum hydrogen. Due to the hydrogen blasting, the gas overflow pores are larger than those normally formed by SLM, and this part of the pores is used to increase the forming surface roughness. , easy to adhere to the growth of tissue and cells.

As a preferred technical solution, the second-level porous structure is specifically:

The second-level porous structure forms a gap due to the gap between the SLM forming melt channel and the melt channel. In addition, a 30-90 degree angle is formed between the current layer melt channel and the next layer melt channel, thereby forming a 10-80 micron porous structure. The microscopic level of this part of the porous structure is relatively small and interconnected.

As a preferred technical solution, the third-level porous structure and the fourth-level porous structure are forward modeled by SolidWorks or UG, or the natural pores obtained by the reverse method of 3D scanning reconstruction, or the Grasshopper plug-in in Rhino software. etc. to parameterize the construction of porous structures.

As a preferred technical solution, the third-level porous structure and the fourth-level porous structure included in the enhanced porous tantalum implant are mainly designed and customized by CAD design software, and the porous structure can be customized through parametric design. The porosity is defined, and the elastic modulus is adjusted by changing the porosity to realize the customization of the implant porosity and elastic modulus.

As a preferred technical solution, the first-level porous structure and the second-level porous structure are distributed on the third-level and fourth-level porous structures designed by CAD.

As a preferred technical solution, after the hydrogen decomposed by tantalum hydride overflows from the molten pool, it combines with the micro-oxygen in the forming chamber to form water, which is driven by the circulating gas and is dried and removed by the filtration system.

The present invention also provides an enhanced porous tantalum implant, which is prepared by the laser selective preparation method of the enhanced porous tantalum implant.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

(1) The present invention breaks through the disadvantage that the laser selective melting forming porous structure can only be limited to the size of a single cell body in the order of hundreds of microns, and cannot form finer pores to facilitate cell adhesion and proliferation. Porous tantalum makes the structure of the implant conform to individual customization. The enhanced structure generated by the decomposition of hydrogen explosion and overflow broadens the extremely small ability of SLM forming, and further enhances the forming ability of laser selective melting and forming of porous tantalum;

(2) The elastic modulus and the like of the multi-level porous tantalum of the present invention make it more biocompatible, especially under the action of the self-assembled nano-tantalum hydrogen hydride proposed in this patent, the enhanced generation generated by decomposing hydrogen explosion and overflowing The structure further reduces the elastic modulus of porous tantalum;

(3) The cells have the strongest adhesion ability to the micro-nano porous structure. The present invention further improves the cell adhesion ability by decomposing the upgraded structure generated by the explosion and overflow of hydrogen, reduces the fretting between the implant and the body, and improves the bonding ability. force;

(4) The density of tantalum is much higher than that of bone. The present invention further reduces the weight of the porous tantalum implant through the enhanced structure generated by the explosion and overflow of decomposed hydrogen, making the implant lighter and more comfortable for the patient to use.

Description of drawings

FIG. 1(a) and FIG. 1(b) are the assembly diagrams of the tantalum powder and the nano-tantalum hydride of the present invention.

Fig. 2 is the formation diagram of the first-stage porous structure in the laser selective melting SLM forming process of the present invention;

Figure 3 is a schematic diagram of a multi-level and cross-scale porous structure;

Fig. 4 is the side view in the case of multi-layer multi-channel;

Figure 5 is a flow chart of the preparation method of the present invention.

Description of reference numerals: 1-spherical tantalum powder; 2-nano tantalum hydride; 3-melting channel; 4-melting channel pores; 5-melting pool; 6-melting pool pores; 7-laser spot; 8-first stage Porous structure; 9-second-level porous structure; 10-third-level porous structure; 11-fourth-level porous structure.

Detailed ways

The present invention will be described in further detail below with reference to the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

Example

The invention forms multi-level porous tantalum under the action of laser selective melting and forming, so that the structure of the implant is in line with individual customization, and the superstructure generated by decomposing hydrogen blasting and overflowing expands the extremely small ability of SLM forming, and enhances the The forming ability of laser selective melting to form porous tantalum is mainly as follows:

Put the tantalum powder attached to the nano-tantalum hydride into the laser selective melting equipment, spread the powder evenly, and then use the appropriate laser process parameters to form, wherein the laser process parameters include laser power, scanning speed, layer thickness, overlap ratio, etc.;

When the laser scans the tantalum powder attached to the nano-tantalum hydride, the focused point energy melts the tantalum powder, and at the same time the nano-tantalum hydride decomposes at high temperature, and hydrogen overflows. The number of air channels depends on the content of nano-tantalum hydride, and after the hydrogen overflows, on the one hand, it continues to consume a small amount of oxygen in the molding chamber, further reducing the possibility of oxidation. On the other hand, although a small amount of water vapor will be produced, the water vapor will be filtered out by a dry filter driven by the circulation of the inert gas.

When the laser is forming a customized implant, on the one hand, it is customized according to the multi-level porous structure required by the design. grade porosity;

Micro- and nano-scale pores are formed on the pore size of the multi-level porous structure, which is easier for cell adhesion and production when contacting the host bone, and further improves the bonding between the host bone and the customized porous tantalum implant.

In the following, the technical solutions of the present invention will be further elaborated in conjunction with specific implementation manners.

As shown in FIG. 5 , a method for preparing an enhanced porous tantalum implant by laser selection in this embodiment includes the following steps:

Step 1: As shown in Figure 1 (a), Figure 1 (b), Figure 2, prepare spherical tantalum powder and nano-tantalum hydride, and combine 5-30 μm spherical tantalum powder 1 with 1-10 nanometer nano-tantalum hydride 2. Mixing, using high-speed ball milling and homogeneous compounding, to assemble and bond the nano-tantalum hydride on the surface of spherical tantalum powder to achieve surface-adhesive assembly.

Step 2: The third-level porous structure 10 and the fourth-level porous structure 11 are designed by 3D CAD design software, and the data is processed and imported into the laser selective melting molding system, and the spherical tantalum powder that has adhered to the nano-tantalum hydride is used as forming material.

In this embodiment, most of the third-level porous structures 10 are 100-500 μm-level porous structures; most of the fourth-level porous structures 11 are 1 mm-10 mm porous structures. This part of the structure is modeled by SolidWorks, UG, etc., and the natural porous structure can also be obtained by inverse methods such as 3D scanning reconstruction. At the same time, the porous structure can be parametrically constructed by the Grasshopper plug-in in Rhino software.

Furthermore, the third-level porous structure 10 and the fourth-level porous structure 11 included in the enhanced porous tantalum implant are mainly designed and customized by CAD design software. The porosity of the porous structure can be defined through parametric design, and the elastic modulus can be adjusted by changing the porosity to realize the customization of the implant porosity and elastic modulus.

Step 3: As shown in Figure 3 and Figure 4, in the process of laser selective melting and forming, under the action of laser radiation with a spot size of 50-100μm, through 300W-500W laser power, according to the scanning speed of 400-1000mm/s 20- The spherical tantalum powder with a thickness of 50 μm is melted to form a melt channel 3. The melt channel has a melt channel air hole 4. The hydride of nano-tantalum in the melt channel decomposes hydrogen due to high temperature, and the hydrogen bursts and overflows under the action of high temperature and high pressure, forming micro-nano scale on the surface of the formed tantalum. structure, this is the first-level porous structure 8, the hierarchical porous structure is mostly 1-500 nm nanometer level, and a few 1-5 micrometer level porous structures.

Further, most of the first-level porous structures 8 form micro-blasting heterogeneous micro-nano pores due to the hydrogen overflow in the tantalum hydrogen. Part of the holes are mainly used to increase the roughness of the forming surface and facilitate the adhesion and growth of tissues and cells;

Step 4: According to the laser process parameters, the scanning surface spacing of 0.08-0.20mm is adopted to form a spacing between the melt channel and the melt channel. At the same time, the scanning direction of the current layer and the scanning direction of the next layer form a certain angle, and the layer The thickness is 20-50 μm, thereby constructing a second-level porous structure 9, which is mostly micron-level and 10-80-micron-level porous structure;

The second-level porous structure 9 is specifically as follows: the structure forms a gap due to the distance between the SLM forming melt channel and the melt channel, and in addition, an included angle of 30-90 degrees is formed between the current layer melt channel and the next layer melt channel, thereby It forms a 10-80 micron porous structure, and the microscopic level of this part of the porous structure is relatively small and interconnected;

Step 5: Design customized multi-level porous structures in combination with CAD formed by SLM, such as the third and fourth level porous structures. This part is mostly model data designed from CAD, and most of the third level structures are 100-500 microns. Micron-level porous structure; the fourth-level porous structure is mostly 1mm-10mm porous structure. Thus, a multi-level porous structure is formed.

Furthermore, the first-level pores and the second-level pores are distributed on the third-level and fourth-level porous structures designed by CAD.

The method of the present application also includes the following steps:

After the hydrogen decomposed by tantalum hydride overflows from the molten pool, it combines with the micro-oxygen in the forming chamber to form water. Driven by the circulating gas, it is dried and removed by the filtration system.

Based on the above-mentioned steps 1 to 4, the above-mentioned four-level porous structure forms a multi-level porous tantalum implant that integrates macro and micro scales across multiple scales such as nanoscale, micro-nanoscale, microscale, and millimeter scale.

The above-mentioned embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above-mentioned embodiments, and any other changes, modifications, substitutions, combinations, The simplification should be equivalent replacement manners, which are all included in the protection scope of the present invention.

Claims (4)

1. a laser selective preparation method for an enhanced porous tantalum implant, is characterized in that, comprises the following steps: Prepare spherical tantalum powder and nano-tantalum hydride, mix 5-30 μm spherical tantalum powder with 1-10 nanometer nano-tantalum hydride, and use high-speed ball milling and homogeneous compounding to assemble and bond the nano-tantalum hydride on the spherical Tantalum powder surface for surface-adhesive assembly; Carry out the design of the third-level porous structure and the fourth-level porous structure, and carry out data processing and import it into a laser selective melting molding system, and use the spherical tantalum powder to which nano-tantalum hydride has been adhered as the molding material. The third-level porous structure is a porous structure of 100-500 μm level, and the fourth-level porous structure is a porous structure of 1-10 mm; In the process of laser selective melting and forming, under the action of laser radiation with a spot size of 50-100 μm, the spherical tantalum powder with a thickness of 20-50 μm is melted according to the set scanning speed to form a single melt channel. Decompose hydrogen, the hydrogen bursts and overflows under the action of high temperature and high pressure, and forms a micro-nano structure on the surface of the formed tantalum, which is the first-level porous structure. Level porous structure; in the process of laser selective melting and forming, forming and forming according to the process parameters of laser power of 300-500W, scanning speed of 400-1000mm/s, layer thickness of 20-50μm, and scanning spacing of 0.08-0.2mm. The preheating requirement is above 200 degrees Celsius; According to the laser process parameters, a scanning distance of 0.08-0.20mm is adopted to form a distance between the melt channel and the melt channel. At the same time, the scanning direction of the current layer and the scanning direction of the next layer form a certain angle, thus constructing the second layer. The first-level porous structure, the second-level porous structure is a 10-80 micron-level porous structure; The third-level porous structure and the fourth-level porous structure included in the enhanced porous tantalum implant are designed and customized by CAD design software, and the porosity of the porous structure can be defined through parametric design, and the porous structure can be defined by parameterized design. The porosity change adjusts the elastic modulus to realize the customization of the implant porosity and elastic modulus; The first-level porous structure is specifically: The first-level porous structure forms micro-blasting heterogeneous micro-nano pores due to the hydrogen overflow in the tantalum hydride. Due to the hydrogen blasting, the gas overflow pores are larger than those normally formed by SLM, and this part of the pores is used to increase the forming surface roughness. , easy to adhere to the growth of tissue and cells; The second-level porous structure is specifically: The second-level porous structure forms a gap due to the distance between the SLM forming melt channel and the melt channel. In addition, a 30-90 degree angle is formed between the current layer melt channel and the next layer melt channel, thereby forming a 10-80 micron porous structure. The microscopic level of this part of the porous structure is relatively small and interconnected; The third-level porous structure and the fourth-level porous structure are forward modeled by SolidWorks or UG, or the natural porous structure obtained by the inverse method of 3D scanning reconstruction, or the parametric construction of porous structures through the Grasshopper plug-in in Rhino software. structure; The above-mentioned four-level porous structure forms an enhanced porous tantalum implant with multiple cross-scale macro-micro integration of cross-level nano-scale, micro-nano-scale, micro-scale and millimeter-scale. 2 . The method for preparing an enhanced porous tantalum implant by laser selection according to claim 1 , wherein the first-level porous structure and the second-level porous structure are distributed in the third and fourth levels of CAD design. 3 . on the porous structure. 3. A kind of laser selective preparation method of an enhanced porous tantalum implant according to claim 1, is characterized in that, after the hydrogen gas decomposed by tantalum hydride overflows from the molten pool, it is combined with the micro-oxygen in the forming chamber to form water, Driven by the circulating gas, it is dried and discharged through the filtration system. 4 . An enhanced porous tantalum implant, characterized in that, it is prepared by the laser selective preparation method for an enhanced porous tantalum implant according to any one of claims 1 to 3 .

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