CN110744054A

CN110744054A - Method for preventing medical laser additive manufacturing porous tantalum prosthesis from being polluted by linear cutting process

Info

Publication number: CN110744054A
Application number: CN201910484320.1A
Authority: CN
Inventors: 郭凯旋; 唐建中
Original assignee: Hunan Printer Medical Devices Co Ltd
Current assignee: Hunan Printer Medical Devices Co Ltd
Priority date: 2019-06-05
Filing date: 2019-06-05
Publication date: 2020-02-04

Abstract

The invention belongs to the technical field of additive manufacturing, and provides a method capable of preventing a porous tantalum prosthesis manufactured by medical laser additive manufacturing from being polluted by a linear cutting process. The method designs a proper support for the printing process between the printing substrate and the designed porous tantalum implant prosthesis, the support is enough to form firm connection between the laser printing substrate and the printed implant prosthesis, the buckling deformation of a printing part is prevented, the printed implant prosthesis is easily taken down from the printing substrate by a manual method after the printing is finished, a linear cutting method is not needed, various pollution in the linear cutting process of the porous tantalum prosthesis is avoided, and the trouble problem that the pollution is difficult to eliminate in the cleaning process is solved.

Description

Method for preventing medical laser additive manufacturing porous tantalum prosthesis from being polluted by linear cutting process

Technical Field

The invention belongs to the technical field of additive manufacturing, and further relates to a method capable of preventing a porous tantalum prosthesis manufactured by a medical laser additive manufacturing process from being polluted by a linear cutting process.

Background

The metal tantalum has excellent biocompatibility and excellent bone conduction, bone induction and bacteriostasis performance, is the metal with the best affinity with human bodies at present, and has been applied for decades. To solve the problem that the traditional processing is difficult due to the high melting point of tantalum metal, the company describes a process method for laser 3D printing of tantalum metal in an issued patent of 'manufacturing method for additive materials of tantalum, niobium or alloy thereof' (patent number ZL 201610322433.8). The patent provides a large-scale, low-cost and simple-process manufacturing method for niobium or tantalum or an alloy additive thereof, but in the practical production and application process of the process method, the pollution problem of the printed porous tantalum prosthesis and a porous tantalum prosthesis product caused by linear cutting oil, linear cutting cooling liquid and a cutting molybdenum wire in the cutting process of a metal substrate is obvious, and the problem is urgently needed to be solved.

The common laser additive manufacturing printed medical porous tantalum prosthesis (including laser 3D printed titanium alloy implant prosthesis) is directly printed on a metal substrate, and a linear cutting method is used for cutting and separating the printed porous tantalum prosthesis from the metal substrate. In the process of linear cutting, the porous tantalum prosthesis is polluted by linear cutting oil, linear cutting cooling liquid and cutting molybdenum wires, the pollution cannot be completely eliminated in the subsequent process of cleaning the human implanted prosthesis, or different complex methods are used for cleaning, and the industrial application is not facilitated.

Disclosure of Invention

Aiming at the problems in the background technology, the invention provides a method for avoiding the pollution of a medical laser additive manufacturing porous tantalum prosthesis caused by a linear cutting process, which is characterized in that a proper printing process support is designed between a printing substrate and a designed porous tantalum implant prosthesis, the support is enough to form firm connection between the laser printing substrate and the printed implant prosthesis, the warping and deformation of a printing part are prevented, the printed implant prosthesis is easy to take off from the printing substrate by a manual method after the printing is finished, the linear cutting method is not needed, various pollutions in the porous tantalum prosthesis linear cutting process are avoided, and the trouble problem that the pollutions are difficult to eliminate in a cleaning process is solved.

The purpose of the invention is realized by the following technical scheme:

a method capable of preventing a medical laser additive manufacturing porous tantalum prosthesis from being polluted by a linear cutting process comprises the following steps:

s1, laser additive manufacturing porous tantalum prosthesis design: establishing a three-dimensional model of the bone repair prosthesis according to CT image data, introducing the model into 3-Matic or other special software capable of designing a mesh structure, and primarily designing all or part of meshes according to the assumption and requirements provided by doctors, wherein the wire diameter of the meshes is 0.15-2.0 mm, the pore diameter of the meshes is 0.2-5 mm, the meshes are of a rhombic 12-face structure, and the porosity of porous tantalum is 40-90%, preferably 60-85%.

S2, support design: carrying out support design between a printing substrate and a designed porous tantalum implantation prosthesis model, wherein the support is composed of a plurality of discontinuous square support units, and each support unit comprises a plurality of unconnected strip-shaped support columns; the present invention is inventive in that the support is sufficient to provide a secure connection between the laser-printed substrate and the printed implant prosthesis, and that the printed implant prosthesis can be easily removed from the printed substrate by hand tools such as pliers, chisels, etc. after printing.

S3, finite element analysis: and predicting the stress conditions of the designed porous tantalum implantation prosthesis structure and the support, and performing finite element analysis to ensure that the prosthesis structure supports, the stress is dispersed and the stress is uniform.

S4.3D printing: carrying out selective laser cladding 3D printing, and printing the porous tantalum implantation prosthesis with the support designed in the preparation steps S1-S3; the invention preferably selects the laser cladding 3D printing process conditions as follows: the diameter of a laser spot is 50-200 um, the speed is 300-900 m/s, the laser power is 200-450W, and the powder spreading thickness is 30-60 um;

further preferably, the invention requires that the tantalum powder used as the raw material for 3D printing is: particle size distribution: d50 is 15-50 um, D10 ≧ 10um D90 ≦ 70 um; fluidity: 50g ≦ 15 seconds; oxygen content ≦ 2000 ppm; the grain type of the tantalum powder can be hydrogenated polyhedral tantalum powder or spherical tantalum powder prepared by various methods.

S5, support dismantling: step S4, after printing is finished and residual powder is blown off, chiseling the printed implanted prosthesis from the printing substrate by a hand tool, and then removing the support left on the porous tantalum implanted prosthesis workpiece; the present invention preferably uses a hand hammer and chisel to chisel the printed implant prosthesis from the print substrate, then uses pliers to remove the support left on the porous tantalum implant prosthesis workpiece, and if necessary, uses a miniature hand grinding wheel to grind away the support trace on the porous tantalum implant prosthesis workpiece.

S6, removing redundant tantalum powder: and (3) placing the porous tantalum implant prosthesis into a sand blasting machine for carrying out sand blasting to remove tantalum powder adhered to the surface and the interior of the implant prosthesis. According to the invention, the sand is preferably hydrogenated and dehydrogenated tantalum powder with the granularity of 200-400 meshes, and the pressure of sand blasting is 0.2-0.5 MPa conventionally.

The invention further preferably selects if the friction coefficient of the porous tantalum implant prosthesis is required to be as large as possible, or the porous tantalum implant prosthesis which is subjected to sand blasting and has the thickness of more than 30mm is required, in order to ensure that the powder does not fall off, the porous tantalum implant prosthesis is taken stably by hand, continuous vibration and striking is carried out on a wooden table top for 3-5 minutes, and the vibration and striking height is within 150 mm. The porous tantalum implant prosthesis was measured for no powder drop as a criterion of 3 times no powder drop from the porous tantalum implant prosthesis in a 200mm high free fall.

In a preferred embodiment of the present invention, in step S2, each of the square supporting units comprises 4 or 9 supporting columns uniformly arranged.

In a preferred embodiment of the present invention, in step S2, a gap of 0.2 to 1.0mm is designed between the square supporting units.

In a preferred embodiment of the present invention, in step S2, the supporting column is divided into an upper section, a middle section and a lower section along the length direction, the cross-sectional dimensions of the middle section are consistent, and the cross-sectional areas of the two ends gradually decrease from the middle section to the two ends; the middle sections among the supporting columns are naturally adjacent without design.

Further preferably, the middle section is 1/3-1/2 of the total length, the lower section is 1/4-1/3 of the total length, and the upper section is 1/3-1/4 of the total length.

Further preferably, the diameter of the cross section of the middle section or the width of the cross section is 0.2-1.0 mm, the shape of the cross section of the upper section or the lower section is the same as that of the middle section, the size of the cross section is gradually reduced towards two ends, and the cross sections are all symmetrical.

Further preferably, the diameter of the contact surface or the width of the cross section of the support pillar and the printing substrate is 0.06-0.25 mm, the diameter of the contact surface or the width of the cross section of the support pillar and the printed porous tantalum implantation prosthesis is 0.05-0.2 mm, and the height of the support pillar is 1-10 mm.

In a preferred embodiment of the present invention, in step S2, the supporting pillars are divided into an upper section, a middle section and a lower section along the length direction, the upper section is connected to the printed porous tantalum implant prosthesis, the lower section is connected to the printed substrate, the cross-sectional dimensions of the middle section and the lower section are the same, the cross-sectional area of the middle section and the lower section gradually decreases along the end direction of the upper section, and the middle sections are naturally adjacent to each other without design.

Further preferably, in step S2, the middle section and the lower section are 2/3 to 3/4 and the upper section is 1/4 to 1/3.

Further preferably, the cross-sectional shape of the upper section of the support column is the same as that of the middle section and the lower section, the cross-sectional dimension of the upper section is gradually reduced towards the end, and the cross sections are all symmetrical shapes.

As a further preferable scheme, the diameter of the contact surface or the width of the cross section of the support column and the printing substrate is 0.05-0.25mm, the diameter of the contact surface or the width of the cross section of the support column and the printed porous tantalum implantation prosthesis is 0.04-0.2mm, the diameter of the cross section of the middle section or the width of the cross section is 0.2-1.0 mm, and the cross sections are all symmetrical shapes.

Compared with the prior art, the invention has the beneficial effects that:

the invention provides a method for preventing a porous tantalum prosthesis manufactured by a medical laser additive from being polluted by a linear cutting process, which creatively designs a support between a printing substrate and the porous tantalum implant prosthesis to be printed, wherein the support is enough to form firm connection between the laser printing substrate and the printed implant prosthesis, prevent the warping and deformation of a printing part, and easily take down the printed implant prosthesis from the printing substrate by a manual method after the printing is finished, so that a linear cutting method is not needed, various pollutions in the online cutting process of the printed porous tantalum prosthesis are avoided, and the trouble problem that the pollutants cannot be easily eliminated in the cleaning process is solved.

Drawings

FIG. 1 is a first design drawing of a cylindrical support structure according to example 1.

Fig. 2 is a second design drawing of the cylindrical support structure of embodiment 1.

FIG. 3 is a design drawing of a porous stent prosthesis model printed in example 13D.

Figure 4 is a first design drawing of a cruciform support structure of example 2.

Figure 5 is a second design drawing of a cruciform support structure of example 2.

Figure 6 is a third design drawing of a cruciform support structure of example 2.

FIG. 7 is a pictorial view of a cross-shaped support printed porous test piece of example 2.

FIG. 8 is a design drawing of a porous stent prosthesis model printed in example 23D.

FIG. 9 is a 3D printed porous stent prosthesis physical representation after the stent is removed in example 2.

Detailed Description

In order to facilitate an understanding of the invention, the invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of the invention is not limited to the specific embodiments below.

Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.

Example 1

The embodiment provides a method capable of preventing a medical laser additive manufacturing porous tantalum prosthesis from being polluted by a linear cutting process, which comprises the following steps:

s1, laser additive manufacturing porous tantalum prosthesis design: establishing a three-dimensional model of the bone repair prosthesis according to CT image data, importing the model into 3-Matic design software, and performing preliminary design of mesh holes on the prosthesis model according to the assumption and the requirement proposed by a doctor, wherein the specific setting in the embodiment is as follows: the wire diameter of the grid is 0.35mm, the pore diameter of the grid is 0.8mm, the meshes are of a rhombic 12-sided body structure, and the designed porosity of the porous tantalum implant is 78.2%.

S2, support design: as shown in fig. 1 and 2, for the detailed design of the supporting structure of the present embodiment, a support is designed between a printed substrate and a designed porous tantalum implant prosthesis model, wherein the support is composed of a plurality of discontinuous square supporting units, and a gap of 0.5mm is designed between the supporting units; each supporting unit comprises 4 unconnected long-strip-shaped circular supporting columns, and the bottom of each supporting column is conical; the supporting column of this embodiment can be divided into an upper segment, a middle segment and a lower segment along the length direction, and the upper segment, the middle segment and the lower segment respectively occupy 1/3 lengths of the total length. The cross section sizes of the middle sections are consistent, and the cross section areas of the middle sections along end points of two ends are gradually reduced; the middle sections of the support columns of the embodiment are cylindrical, and the middle sections among the single cylindrical support columns are naturally adjacent to each other in an off-design mode. The upper section and the lower section of the support column are in the shape of a cone, the cross section of the upper section and the lower section of the support column are the same as that of the middle section, and the cross section size is gradually reduced towards two ends;

in this embodiment, the diameter of the middle section of each single cylindrical support is 0.8mm, the distance between the shafts of the single cylindrical supports is 0.8mm, the diameter of the end face of the porous tantalum implant prosthesis printed by the connection of the single cylindrical support is 0.2mm, and the diameter of the end face of the substrate printed by the connection of the single cylindrical support is 0.25 mm. The minimum height of the support column is 3 mm.

S3, finite element analysis: and predicting the stress conditions of the designed porous tantalum implantation prosthesis structure and the support, and performing finite element analysis to disperse the stress of the prosthesis structure and the support and ensure uniform stress.

S4.3D printing: as shown in fig. 3, for the 3D printed design drawing of the present embodiment, selective laser cladding 3D printing is performed with reference to fig. 3, and the porous tantalum implant prosthesis with a support designed in the preparation steps S1 to S3 is printed; the laser cladding 3D printing process conditions described in this embodiment are: the diameter of a laser spot is 100um, the speed is 500m/s, the laser power is 350W, and the powder spreading thickness is 50 um;

meanwhile, the 3D printing of the embodiment uses the raw material tantalum powder with the lot number 181221-: d50 ═ 29.38um, D10 ═ 10.56um, D90 ═ 58.99 um; fluidity: 50g/13.7 s; oxygen content 1138 ppm; the particle type of the tantalum powder is hydrogenated polyhedral tantalum powder.

S5, support dismantling: step S4, after printing is finished and residual powder is blown off, chiseling the printed implanted prosthesis sample from the printing substrate by the cooperation of a hand hammer and a chisel, and then removing the support left on the porous tantalum implanted prosthesis workpiece by a clamp; and then a micro hand grinding wheel is used for grinding and removing the support traces on the porous tantalum implantation prosthesis workpiece.

S6, removing the adhered tantalum powder: placing the porous tantalum implantation prosthesis into a sand blasting machine for carrying out sand blasting to remove tantalum powder adhered to the surface and the interior of the implantation prosthesis; the sand used in the embodiment is hydrogenated and dehydrogenated tantalum powder with the granularity of 200-400 meshes (44-150 um), and the pressure of sand blasting is 0.5MPa in the conventional mode.

Example 2

s1, laser additive manufacturing porous tantalum prosthesis design: establishing a three-dimensional model of the bone repair prosthesis according to CT image data, importing the model into 3-Matic design special software, and carrying out primary design according to the assumption and the requirement proposed by a doctor, wherein: the mesh has a wire diameter of 0.3mm, the mesh has a pore diameter of 0.75mm, the mesh has a rhombic 12-sided structure, and the porous tantalum implant of the present embodiment requires a designed porosity of 80.78%.

S2, support design: as shown in fig. 4 to 6, for the detailed design diagram of the cross-shaped support structure of the present embodiment, a support design is performed between the printed substrate and the designed porous tantalum implant prosthesis, wherein the support is composed of a plurality of discontinuous square support units, and a gap of 0.6mm is designed between the support units; each support unit includes 9 disconnected, rectangular form cross support columns, the support column divide into upper segment, interlude and hypomere along length direction, upper segment, interlude, hypomere respectively account for 1/3 of total length long, respectively set up to 1mm long in this embodiment. The cross section sizes of the middle sections of the supports are consistent, and the cross section areas along the end points of the lower sections and the end points of the upper sections are gradually reduced; the middle sections of the single cross-shaped supporting columns are naturally adjacent to each other in a non-designed way. The cross section shapes of the upper section and the lower section of the support column are the same as the middle section, and the cross section size is gradually reduced from the middle section to the end points of the two ends;

in this embodiment, section cross length is 0.4mm in the middle of single cross support, and thickness 0.05mm, the middle section height is 1mm, and each length of two end cones is 1mm, and the terminal surface cross length that false body was implanted to the porous tantalum that each single cross support connection printed is 0.1mm, and the terminal surface cross length that single cross support connection printed the base plate is 0.12 mm.

Referring to fig. 6, in the present embodiment, each support unit has a square edge on the periphery of the cross section, the thickness of the edge is 0.1mm, the side length of the square edge on the middle section of the square edge in the length (height) direction is 1.2mm, and the cross section of the contact end with the printed porous implant prosthesis is 0.4 mm; the cross-section of the end in contact with the printed substrate was square with a side of 0.48 mm.

S4.3D printing: as shown in fig. 8, in order to print the design drawing in 3D according to this embodiment, selective laser cladding 3D printing is performed with reference to fig. 8, and the porous tantalum implant prosthesis with a support, which is designed in the preparation steps S1 to S3, is printed; the laser cladding 3D printing process conditions described in this embodiment are: the diameter of a laser spot is 100um, the speed is 600m/s, the laser power is 300W, and the powder spreading thickness is 45 um;

meanwhile, in the 3D printing of the embodiment, the raw material tantalum powder is spherical tantalum powder prepared by a plasma method with a batch number of QTa 190212: particle size distribution: d50 ═ 31.36um, D10 ═ 12.93um, D90 ≦ 56.59 um; fluidity: 50g ≦ 8.6 seconds; an oxygen content of 1320ppm or less; the spherical tantalum powder is prepared by the tantalum powder plasma method. Referring to fig. 7, a cross-shaped support was printed with a physical map of the porous test piece.

S5, support dismantling: referring to fig. 9, a 3D printed porous stent prosthesis object map after support removal is shown. After printing is finished and residual powder is blown off in the step S4, chiseling the printed implanted prosthesis from the printing substrate by using a tool, and then removing the support left on the porous tantalum implanted prosthesis workpiece; the present invention preferably uses a hand hammer and chisel to chisel the printed implant prosthesis from the print substrate, then uses pliers to remove the support left on the porous tantalum implant prosthesis workpiece, and if necessary, uses a miniature hand grinding wheel to grind away the support trace on the porous tantalum implant prosthesis workpiece.

S6, removing redundant tantalum powder: and (3) placing the porous tantalum implant prosthesis into a sand blasting machine for carrying out sand blasting to remove tantalum powder adhered to the surface and the interior of the implant prosthesis. The sand used in the embodiment is hydrogenated and dehydrogenated tantalum powder with the granularity of 200-400 meshes (44-150 um), and the pressure of sand blasting is 0.5MPa in the conventional mode.

Claims

1. A method for preventing a medical laser additive manufacturing porous tantalum prosthesis from being polluted by a linear cutting process is characterized by comprising the following steps:

s1, laser additive manufacturing porous tantalum prosthesis design: establishing a three-dimensional model of the bone repair prosthesis, introducing the model into 3-Matic or other special software capable of carrying out mesh structure design, and carrying out primary design of mesh on the prosthesis model;

s2, support design: carrying out support design between a printing substrate and a designed porous tantalum implantation prosthesis model, wherein the support is composed of a plurality of discontinuous square support units, and each support unit comprises a plurality of unconnected strip-shaped support columns;

s3, finite element analysis: predicting stress conditions of the designed porous tantalum implantation prosthesis structure and the support, and performing finite element analysis to disperse the prosthesis structure, the support and stress and ensure uniform stress;

S4.3D printing: carrying out selective laser cladding 3D printing, and printing the porous tantalum implantation prosthesis with the support designed in the preparation steps S1-S3;

s5, support dismantling: step S4, after printing is finished and residual powder is blown off, chiseling the printed implanted prosthesis from the printing substrate by using a hand tool, and then manually removing the support left on the porous tantalum implanted prosthesis workpiece;

s6, removing the adhered tantalum powder: and removing tantalum powder adhered to the surface and the interior of the porous tantalum implantation prosthesis by various methods such as air blowing, sand blasting, vibration knocking and the like.

2. The method for avoiding the contamination of the medical laser additive manufacturing porous tantalum prosthesis caused by the wire cutting process according to claim 1, wherein in step S2, each square support unit comprises 4 or 9 support columns uniformly arranged, and a gap of 0.2-1.0 mm is designed between the square support units.

3. The method for avoiding the contamination of the porous tantalum prosthesis by the wire-electrode cutting process in the medical laser additive manufacturing process according to claim 1, wherein in step S2, the supporting column is divided into an upper section, a middle section and a lower section along the length direction, the cross section of the middle section is uniform in size, and the cross sections of the two ends are gradually reduced from the middle section to the two ends; the middle sections between the adjacent supporting columns are naturally adjacent without design.

4. The method for avoiding the contamination of the medical laser additive manufacturing porous tantalum prosthesis caused by the wire cutting process as claimed in claim 3, wherein the middle section of the single support column is 1/3-1/2 of the total length, the lower section is 1/4-1/3 of the total length, and the upper section is 1/4-1/3 of the total length.

5. The method for avoiding the contamination of the medical laser additive manufacturing porous tantalum prosthesis caused by the wire cutting process according to claim 3, wherein the diameter of the cross section or the width of the cross section of the middle section of the single support column is 0.2-1.0 mm, the cross section of the upper section or the lower section is the same as that of the middle section, the cross section size is gradually reduced towards two ends, and the cross sections are symmetrical.

6. The method for avoiding the contamination of the medical laser additive manufacturing porous tantalum prosthesis caused by the wire cutting process according to any one of claims 3 to 5, wherein the diameter of the contact surface or the width of the cross section of the support pillar and the printing substrate is 0.06-0.25 mm, the diameter of the contact surface or the width of the cross section of the support pillar and the printed porous tantalum implant prosthesis is 0.05-0.2 mm, and the height of the support pillar is 1-10 mm.

7. The method for preventing contamination of a porous tantalum prosthesis by a wire cutting process in medical laser additive manufacturing according to claim 1, wherein in step S2, the supporting pillars are divided into an upper section, a middle section and a lower section along the length direction, the upper section is connected with the printed porous tantalum implant prosthesis, the lower section is connected with the printed substrate, the middle section and the lower section have the same cross-sectional size, the cross-sectional area gradually decreases along the end direction of the upper section, and the middle sections are adjacent to each other in an unintended nature.

8. The method for avoiding the contamination of the medical laser additive manufacturing porous tantalum prosthesis by the wire cutting process according to claim 7, wherein in the step S2, the middle section and the lower section are 2/3-3/4 and the upper section is 1/4-1/3 of the total length.

9. The method for avoiding the contamination of the porous tantalum prosthesis by the wire cutting process in the medical laser additive manufacturing process according to claim 7, wherein the cross section of the upper section of the support column is the same as that of the middle section and the lower section, the cross section of the upper section is gradually reduced towards the end, and the cross sections are symmetrical.

10. The method for preventing the medical laser additive manufacturing porous tantalum prosthesis from being polluted by the wire cutting process according to any one of claims 7 to 9, wherein the diameter of the contact surface or the width of the cross section of the support pillar and the printing substrate is 0.05 to 0.25mm, the diameter of the contact surface or the width of the cross section of the support pillar and the printed porous tantalum implant prosthesis is 0.04 to 0.2mm, the diameter of the cross section or the width of the cross section of the middle section is 0.2 to 1.0mm, and the cross sections are symmetrical shapes.