Selective laser melting (SLM) molding method for magnesium alloy stent

A technology for selective laser melting and magnesium alloy blood vessels, which is applied in the field of magnesium alloy parts manufacturing, can solve the problems of low manufacturing accuracy, toxic release, low yield, etc., and achieves high shape and dimensional accuracy, simple processing procedures, and good mechanical properties. Effect

Active Publication Date: 2012-12-05
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although these metal biomaterials are easy to manufacture, they have disadvantages: they may release toxic metal ions or metal particles during corrosion or wear, resulting in tissue defects and reduced biocompatibility
The processed surface of the vascular stent obtained by this method is relatively rough, often with burrs, the manufacturing precision is not high, and the yield is also very low, which greatly restricts its application and promotion

Method used

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  • Selective laser melting (SLM) molding method for magnesium alloy stent
  • Selective laser melting (SLM) molding method for magnesium alloy stent
  • Selective laser melting (SLM) molding method for magnesium alloy stent

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Such as figure 1 As shown, the selective laser melting forming method of the magnesium alloy vascular stent specifically includes the following steps:

[0035] (1) Establish the geometric model of the vascular stent in the host computer, perform layered discretization on the geometric model, and generate a scanning path according to the geometric contour;

[0036] (2) inject inert gas into the molding chamber, and control the oxygen concentration in the molding chamber within a certain concentration range;

[0037] (3) The powder supply device supplies the metal powder to the molding cylinder in the molding chamber, and the powder spreading device pre-spreads it on the molding cylinder;

[0038] (4) The metal powder is scanned by laser, and the laser is emitted and transmitted by the laser, forming a focused spot on the processing plane of the metal powder, melting the metal powder, and forming a single-layer cross-section of the vascular stent;

[0039] (5) Determine...

Embodiment 2

[0054]This embodiment is the same as Embodiment 1 except for the following features: the powder feeding device is a powder feeding cylinder, the powder spreading device is a scraper, and the step (4) uses a fiber laser to emit laser light. In the step (2), the injected inert gas is high-purity nitrogen with a purity of 99.99%.

[0055] In the step (3), before the metal powder is placed on the base plate of the molding cylinder, it is first heated by a heating wire arranged under the base plate or in the powder spreading device, so that the temperature of the metal powder reaches 130°C.

[0056] In the step (2), the oxygen concentration in the molding chamber is controlled within a concentration range of 8 ppm.

[0057] The average particle size of the magnesium alloy powder is 5 μm.

[0058] The diameter of the focused light spot in the step (4) is 50 μm.

[0059] In the step (4), the laser performs interlayer staggered scanning on the metal powder, and at the same time scan...

Embodiment 3

[0062] This embodiment has the same characteristics as Embodiment 1 except for the following features: in the step (3), before the metal powder is preset to the substrate of the molding cylinder, it is first heated by a heating wire arranged under the substrate or in the powder spreading device , so that the temperature of the metal powder reaches 120°C.

[0063] In the step (2), the injected inert gas is high-purity nitrogen with a purity of 99.999%.

[0064] In the step (2), the oxygen concentration in the molding chamber is controlled within a concentration range of 6 ppm.

[0065] The average particle size of the magnesium alloy powder is 10 μm.

[0066] The diameter of the focused light spot in the step (4) is 40 μm.

[0067] In the step (4), the laser performs interlayer staggered scanning on the metal powder, and at the same time scans the outline of the part, the scanning speed of the laser outline is 130mm / s; the power of the laser is 180W; the The scanning speed i...

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Abstract

The invention provides a selective laser melting (SLM) molding method for a magnesium alloy stent, comprising the following steps: (1) constructing a stent geometrical model in an upper computer, layering and dispersing the geometrical model, and generating a scanning path based on the geometrical model; (2) injecting inert gas in a molding chamber and controlling the oxygen concentration in the molding chamber within a certain concentration range; (3) supplying metal powder to a molding cylinder in the molding chamber by a powder supplier and spreading the metal powder on the molding cylinder by a powder spreading device; (4) adopting laser to scan the metal powder; (5) judging whether the stent is molded or not, if so, taking a stent molding piece out, and otherwise, executing the next steps; and (6) descending the molding cylinder by one layer, repeating the steps of (3), (4) and (5), and melting the metal powder layer by layer until deposition molding to obtain the molded magnesium alloy stent. The invention can mold stents with grids in arbitrary shapes and has the advantages of high manufacture precision and the like.

Description

technical field [0001] The invention belongs to the technical field of manufacturing magnesium alloy parts, and in particular relates to a selective-area laser melting forming method of a magnesium alloy vascular stent. Background technique [0002] In medical treatment, vascular stent implantation is often used to dredge narrowed or blocked blood vessels of patients. Clinical vascular stents are generally made of 316L stainless steel, titanium alloy, magnesium alloy and other metals. Although these metal biomaterials are easy to manufacture, they have disadvantages: they may release toxic metal ions or metal particles during corrosion or wear, which may cause tissue defects and reduce biocompatibility. Furthermore, the modulus of elasticity of these metallic biomaterials is not quite commensurate with that of normal bone tissue, leading to a stress shielding effect that destabilizes the implant and necessitates a secondary surgery to remove it after the patient has fully h...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22F3/105
CPCY02P10/295Y02P10/25
Inventor 杨永强苏旭彬王迪孙婷婷
Owner SOUTH CHINA UNIV OF TECH
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