阅读说明：本技术 一种胆道植入体及其制作方法 (Biliary tract implant and manufacturing method thereof ) 是由 郑元文 于 2020-12-31 设计创作，主要内容包括：一种胆道植入体及其制作方法,所述胆道植入体主体为管状结构,采用镍钛形状记忆合金通过激光选区熔化工艺制作而成,该胆道植入体在轴向上包含自下而上排列的第一分区段位Ⅰ、第二分区段位Ⅱ和第三分区段位Ⅲ,至少第一分区段位Ⅰ和第三分区段位Ⅲ在使用中具有形状记忆效应并且具有不同的相变温度范围,所述不同的相变温度范围是通过在铺粉和扫描熔化过程中保持粉末成分不变,在不同的分区段位改变激光扫描参数,同时配合对其中至少部分铺粉层激光扫描次数的改变来获得。本发明根据胆道植入体在使用中的功能(例如胆肠吻合)进行相变分区设计,借助激光选区熔化的能量控制技术实现了快速制作,在确保力学性能的基础上提高了功能区的相变控制精度。(A biliary tract implant and its making method, the said biliary tract implant body is a tubular structure, adopt nickel titanium shape memory alloy to select the district melting process to make through the laser, the biliary tract implant body includes the first sectional site I, the second sectional site II and the third sectional site III arranged from bottom to top in the axial direction, at least the first sectional site I and the third sectional site III have shape memory effect and have different phase transition temperature ranges in use, the said different phase transition temperature ranges are through keeping the powder composition unchanged in the course of powder laying and scanning melting, change the laser scanning parameter in different sectional sites, cooperate to spread the change of the laser scanning number of times of the powder layer among them to obtain at least partly at the same time. The invention carries out phase change partition design according to the functions (such as biliary-enteric anastomosis) of the biliary tract implant in use, realizes quick manufacture by means of the energy control technology of selective laser melting, and improves the phase change control precision of the functional area on the basis of ensuring the mechanical property.)

1. A biliary tract implant, the main body of which is a tubular structure and is made of shape memory alloy by an additive manufacturing process, is characterized in that the biliary tract implant comprises a plurality of subsection positions in the axial direction, wherein at least two subsection positions have shape memory effect and different phase transition temperature ranges in use.

2. The biliary implant of claim 1, wherein the additive manufacturing process is a metal laser selective melting process.

3. The biliary implant of claim 1 or 2, wherein the shape memory alloy is nitinol.

4. A method for manufacturing a biliary tract implant according to any one of claims 1 to 3, comprising the steps of:

step 1, designing a biliary tract implant model according to medical image data of a part of a human biliary tract needing to be supported;

step 2, guiding the biliary tract implant model into laser selective melting equipment, carrying out layered slicing on the biliary tract implant model by taking the axial direction as the printing direction of additive manufacturing, and planning a laser scanning path and laser scanning parameters of each layer of slice;

step 3, after the substrate is preheated, the selective laser melting equipment performs powder paving and scanning melting of nickel-titanium alloy powder according to a program, wherein the powder paving and scanning melting are alternately performed until a biliary tract implant component is obtained, and the selective laser melting equipment comprises:

along the printing direction, the biliary tract implant comprises at least three segmental positions in the axial direction: a first section (I), a second section (II) and a third section (III), the first section (I), the second section (II) and the third section (III) are arranged from bottom to top along the printing direction, the second section (II) is arranged between the first section (I) and the third section (III), wherein, at least the first section (I) and the third section (III) have shape memory effect and different phase-change temperature ranges, the different phase-change temperature ranges are obtained by keeping the components of the laid nickel-titanium alloy powder unchanged during the powder laying and scanning melting process, changing the laser scanning parameters at different sections and matching with the change of the laser scanning times of at least part of the laid powder layer, in particular, when the first section (I) is printed, and scanning and melting each powder laying layer by adopting a first laser scanning parameter, scanning and melting each powder laying layer by adopting a second laser scanning parameter when printing a third section position (III), and increasing the laser scanning times to be more than or equal to 2 times for at least partial powder laying layers in the third section position (III).

5. The method for manufacturing a biliary tract implant according to claim 4, wherein in step 3, specifically, in printing the first segment (I), the powder layers are melted by scanning with a first laser scanning parameter and the first laser scanning parameter is constant in the powder layers of the first segment (I), and in printing the third segment (III), the powder layers are melted by scanning with a second laser scanning parameter and the second laser scanning parameter is varied between at least part of the powder layers of the third segment (III).

6. The method as claimed in claim 4, wherein the second segment (II) has no shape memory effect in use, or the second segment (II) has shape memory effect in use, but has a phase transition temperature range different from that of the third segment (III) and the same as or different from that of the first segment (I).

7. The method as claimed in claim 4, wherein the laser scanning parameters are one or more of laser scanning interval, laser scanning power and laser scanning speed.

8. Method for producing a biliary implant according to claim 7, wherein at least two laser scanning parameters are preferably changed simultaneously during the printing of the respective segment, in particular of the third segment (III).

9. The method for manufacturing a biliary tract implant according to claim 4, wherein the phase transition temperature range of the third segment (III) is based on the body temperature inside the body cavity.

10. The method as claimed in claim 4, wherein the nickel-titanium alloy is nickel-titanium alloy with nickel atom content of 50.0-51.5%.

Technical Field

The invention relates to the technical field of metal additive manufacturing, in particular to a biliary tract implant with shape memory effect manufactured by additive manufacturing and a method for manufacturing the biliary tract implant by adopting shape memory alloy through a selective laser melting process.

Background

The selective melting (SLM) technology of metal laser is a technology that metal powder is melted and solidified quickly under the heat action of laser beam, the metal powder is melted completely under the action of high-energy laser, and is metallurgically welded with base metal after heat dissipation and solidification, and then a three-dimensional entity is formed by layer-by-layer accumulation. The metal laser selective melting (SLM) technology can disperse solid parts into independent layers and manufacture the layers layer by layer, so that the complex shapes can be formed, and laser processing parameters can be easily adjusted at any time in the part manufacturing process to meet the product control requirements.

Shape Memory Alloy (SMA) can realize shape memory through thermoelastic martensite phase change generated in the material, and is widely applied in the clinical medical field, a plurality of artificial tissues or auxiliary stents implanted into a human body, such as artificial bones and endoluminal stents, are manufactured by adopting a metal laser selective melting (SLM) process, wherein a biliary stent is a relatively special endoluminal stent, a common biliary-intestinal anastomosis stent is taken as an example, when the SMA is manufactured, different parts in the axial direction of the stent possibly need different temperature memory effects, a section of the stent is formed as an upper section, a section connected with a flow guide tube is taken as a lower section, a part between the biliary stent and the flow guide tube is taken as a middle section, the upper section supports the biliary tract, the SMA needs to have shape memory capacity within a temperature range based on the body temperature, the lower section is connected with the flow guide tube, in order to prevent unnecessary looseness, the phase transition temperature range is far from the temperature range of the upper section.

At present, a metal laser selective melting (SLM) process is adopted to plan the phase transition temperature of different parts of the same workpiece, mature means mainly comprise a composition adjustment method and a heat treatment method, for example, nickel-titanium alloy, as the phase transition temperature is highly related to the atomic ratio of nickel and titanium, different phase transition temperatures can be obtained at different parts by adjusting the atomic ratio of the two elements, the heat treatment method is to influence the internal phase composition by a heat treatment mode of a manufacturing part, and for the nickel-titanium alloy, Ni is introduced₄Ti₃The two-phase particles achieve the effect of changing the relative contents of nickel and titanium and further adjusting the phase transition temperature, wherein the former method has complicated operation,The accuracy is low and the regulating effect of the latter is very difficult to predict and control.

Disclosure of Invention

In order to solve the problems, the invention provides a biliary tract implant and a manufacturing method thereof, wherein phase change partition design is carried out according to the in-use function of the biliary tract implant, rapid manufacturing is realized by means of an energy control technology of selective laser melting, and the phase change control precision of a functional area is improved on the basis of ensuring the mechanical property.

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

A biliary tract implant is of a tubular structure, is made of shape memory alloy through an additive manufacturing process, and comprises a plurality of subsection positions in the axial direction, wherein at least two subsection positions have shape memory effect and different phase transition temperature ranges in use.

Preferably, the additive manufacturing process is a metal selective laser melting process.

Preferably, the shape memory alloy is a nickel titanium alloy.

The method for manufacturing the biliary tract implant comprises the following steps:

step 1, designing a biliary tract implant model according to medical image data of a part of a human biliary tract needing to be supported;

step 2, guiding the biliary tract implant model into laser selective melting equipment, carrying out layered slicing on the biliary tract implant model by taking the axial direction as the printing direction of additive manufacturing, and planning a laser scanning path and laser scanning parameters of each layer of slice;

step 3, after the substrate is preheated, the selective laser melting equipment performs powder paving and scanning melting of nickel-titanium alloy powder according to a program, wherein the powder paving and scanning melting are alternately performed until a biliary tract implant component is obtained, and the selective laser melting equipment comprises:

along the printing direction, the biliary tract implant comprises at least three segmental positions in the axial direction: a first section position, a second section position and a third section position, the first section position, the second section position and the third section position are arranged from bottom to top along the printing direction, the second section position is positioned between the first section position and the third section position, wherein, at least the first section position and the third section position have shape memory effect and different phase change temperature ranges in use, the different phase change temperature ranges are obtained by keeping the components of the laid nickel-titanium alloy powder unchanged during the powder laying and scanning melting processes, changing laser scanning parameters at different section positions and simultaneously matching the change of the laser scanning times of at least part of the powder laying layer, in particular, when the first section position is printed, each powder laying layer is scanned and melted by adopting the first laser scanning parameters, when the third section position is printed, and scanning and melting each powder laying layer by adopting a second laser scanning parameter, and increasing the laser scanning times to be more than or equal to 2 times for at least partial powder laying layers in the third section position.

Preferably, in step 3, in particular, when printing the first segment bit, the powder-laying layers are scan-melted using a first laser scanning parameter and the first laser scanning parameter is constant in the powder-laying layers of the first segment bit, and when printing the third segment bit, the powder-laying layers are scan-melted using a second laser scanning parameter and the second laser scanning parameter is varied between at least part of the powder-laying layers of the third segment bit.

Preferably, the second segment bit has no shape memory effect in use, or the second segment bit has shape memory effect in use, but a phase transition temperature range is different from that of the third segment bit, the same as or different from that of the first segment bit.

Preferably, the laser scanning parameter is one or more of a laser scanning pitch, a laser scanning power, and a laser scanning speed.

Preferably, at least two laser scanning parameters are changed simultaneously during the printing of the individual segment bits, in particular of the third segment bit.

Preferably, the phase transition temperature range of the third section position takes the body temperature in the human body cavity as a reference.

Preferably, the nickel titanium alloy is a nickel titanium alloy having a nickel atom content of between 50.0% and 51.5%.

The invention has the beneficial effects that:

the biliary tract implant and the manufacturing method thereof of the invention carry out phase change partition design according to the function of the biliary tract implant in use, realize quick manufacturing by means of energy control technology of laser selective partition melting, and divide the biliary tract implant into a first partition position, a second partition position and a third partition position in the axial direction along the printing direction, so that the first partition position corresponds to the connection end of a diversion pipe of the biliary tract implant, the third partition position corresponds to the support supporting section of the biliary tract implant, and further, when the first partition position is printed, each powder laying layer is scanned and melted by adopting a first laser scanning parameter, and when the third partition position is printed, each powder laying layer is scanned and melted by adopting a second laser scanning parameter, so that the first partition position and the third partition position respectively have different phase change temperature ranges according to the installation requirement of a sleeve and the expansion requirement in a cavity.

When the method of the invention carries out selective laser melting, aiming at the third section position which is taken as a main functional area, the second laser scanning parameters which are changed among the powder laying layers are selected to scan and melt each powder laying layer, so that the third section position has gradient phase change effect in the axial direction, and in practical application, for example, the method can play a role in ensuring that a stent supporting section of a biliary tract implant can extend along with temperature relief in a cavity after operation, and the method can replace means such as simply increasing the laser scanning power or simply reducing the laser scanning speed when increasing the laser scanning times to be more than or equal to 2 times for partial powder laying layers in the third section position, thereby preventing the upper limit value of the laser scanning power from being too high or the lower limit value of the laser scanning speed from being too low and exceeding the boundary value of the processing parameters which are determined according to theory or verified normal process routes and ensure that the components keep the best internal quality, thereby improving the phase change control precision of the functional area on the basis of ensuring the mechanical property.

Drawings

The aspects and advantages of the present application will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. In the drawings:

fig. 1 is a schematic structural view of a biliary tract implant according to embodiment 1 of the present invention.

In the figure: a first partition level-I, a second partition level-II, and a third partition level-III.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings.

Example 1

A biliary tract implant is shown in figure 1, and has a tubular main body, and is made of nickel-titanium shape memory alloy by a selective laser melting process, and comprises three segmental positions in the axial direction: a first section level i, a second section level ii and a third section level iii, which are arranged from bottom to top along the printing direction, the second section level ii being located in between the first section level i and the third section level iii, wherein at least the first section level i and the third section level iii have a shape memory effect in use and have different phase transition temperature ranges.

By way of example and not limitation, the first segment i is a segment of a biliary tract implant for biliary-enteric anastomosis, which is sleeved with a drainage tube, the third segment iii is a biliary tract stent support segment with a malleable stent, and the second segment ii is a connection extension segment therebetween.

Example 2

The method of making the biliary implant of example 1, comprising the steps of:

step 1, designing a biliary tract implant model according to medical image data of a part of a human biliary tract needing to be supported;

step 2, guiding the biliary tract implant model into laser selective melting equipment, carrying out layered slicing on the biliary tract implant model by taking the axial direction as the printing direction of additive manufacturing, and planning a laser scanning path and laser scanning parameters of each layer of slice;

step 3, after preheating the substrate, performing powder paving and scanning melting of nickel-titanium alloy powder (preferably, the content of nickel atoms is between 50.0% and 51.5%) by using a laser selective melting device according to a program, wherein the powder paving and the scanning melting are alternately performed until a biliary tract implant component is obtained, wherein:

along the printing direction, the biliary tract implant comprises three segmental positions in the axial direction: a first section I, a second section II and a third section III, which are arranged from bottom to top along the printing direction, the second section II is located between the first section I and the third section III, wherein the first section I and the third section III have shape memory effect and different phase change temperature ranges in use, the different phase change temperature ranges are obtained by keeping the components of the laid nickel-titanium alloy powder unchanged during the powder laying and scanning melting process, changing laser scanning parameters at different sections and simultaneously changing the laser scanning times of at least part of the powder laying layer, and particularly, when the first section I is printed, scanning and melting each powder laying layer by using the first laser scanning parameters, and when the third section position III is printed, scanning and melting each powder laying layer by adopting a second laser scanning parameter, and increasing the laser scanning times to be more than or equal to 2 times for at least partial powder laying layers in the third section position III. Preferably, during printing of the first section level i, the powder layers are melted by scanning with a first laser scanning parameter, the first laser scanning parameter being constant in the powder layers of the first section level i, and during printing of the third section level iii, the powder layers are melted by scanning with a second laser scanning parameter, the second laser scanning parameter varying between at least some of the powder layers of the third section level iii.

In this embodiment, the second segment ii is not particularly limited, and may not have a shape memory effect in use (not phase-change under extreme temperature conditions in a cavity and in a natural environment), or the second segment ii may have a shape memory effect in use, but a phase-change temperature range different from that of the third segment iii is the same as or different from that of the first segment i.

Preferably, the laser scanning parameters are one or more of laser scanning pitch, laser scanning power and laser scanning speed, and at least two laser scanning parameters can be simultaneously changed when each segment bit, especially the third segment bit iii, is printed, for example, the laser scanning speed can be appropriately reduced (in a small range) while the laser scanning power is reduced (in a large range), so that the variation range of the mechanical property and the phase transition temperature is alleviated.

Example 3

YAG laser is used in the embodiment, each powder layer of the first section I is subjected to laser scanning with constant power of 100W, a phase transition section with a phase transition temperature below 0 ℃ can be obtained after the scanning speed exceeds 0.9m/s, each powder layer of the third section III is subjected to laser scanning with decreasing power from 120W to 80W, and a phase transition section with a phase transition temperature range of 36.5 +/-7.1 ℃ can be obtained at the scanning speed of about 0.4m/s on average.

Example 4

In this embodiment, on the basis of embodiment 3, the portion of the third segment position iii, where the laser scanning power is distributed between 110-120W, is changed to scan each powder layer 2 times with the power of 105W and 110W respectively, where the phase transition temperature range high point reached by the power of 110W is both exceeded and is close to the phase transition temperature range high point reached by the power of 120W.

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention shall be subject to the protection scope of the appended claims.