Method for preparing shape memory alloy intravascular stent based on automatic powder laying laser combination machining technology

Abstract

The invention discloses a method for preparing a shape memory alloy intravascular stent based on the automatic powder laying laser combination machining technology. The method comprises the steps that according to a three-dimensional data model of a part to be machined, a high-energy laser beam melting and mixing powder system is utilized, the manner of laying powder layer by layer and carrying out fusing overlaying accumulation layer by layer is carried out until a intravascular stent blank of a mesh structure is formed finally, and then electrochemical polishing is carried out to reach the specific surface roughness requirement. The intravascular stent prepared through the method is based on the unique superelasticity function and the shape memory effect of shape memory alloy, and the occurrence rate of vascular restenosis of the intravascular stent in clinical application can be effectively reduced; by means of mechanical performance and living body environment simulation tests, the intravascular stent has the good biological tissue and blood compatibility and meets the medical application condition; furthermore, based on the advantage of superhigh manufacturing precision of the laser combination machining technology and protection of inert gas in the forming process, the problems of surface roughness, burr, oxidation and the like of a traditional intravascular stent in the preparing process are effectively solved.

Description

technical field [0001] The invention relates to a method for preparing a shape-memory alloy vascular stent based on an automatic powder-spreading laser combination processing technology, and belongs to the technical field of medical device manufacturing. Background technique [0002] After the 1990s, minimally invasive interventional treatment of vascular diseases began to be widely used. At present, it has been recognized as one of the most effective means for the treatment of cardiovascular and cerebrovascular diseases. According to different vascular lesions and requirements, researchers and doctors have jointly developed vascular stents with superior performance. There are many factors that determine the performance of vascular stents, among which the two most important are the selection of appropriate stent materials and the selection of appropriate stent manufacturing processes. [0003] At present, the most commonly used vascular stent is a nickel-titanium alloy vasc...

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Problems solved by technology

[0004] Although the above-mentioned nickel-titanium alloy has many excellent characteristics, it has the following disadvantages: 1. The cost and difficulty of the processing and post-treatment process of the nickel-titanium alloy stent are higher than those of stainless steel 316L. The commonly used nickel-titanium alloy vascular stent is usually It is braided by shape memory alloy wire or shaped by laser engraving of shape memory alloy. It can be seen that such vascular stents have high production costs, limited stent structure design, and it is difficult to realize complex shapes of vascular stents. 2. The temperature sensitivity of Nitinol stent is very high, and obvious temperature changes will cause changes in the performance of the stent. Therefore, it has a certain impact on storage and transportation. condition requirements; at present, the commonly used nickel-titanium alloy stent is a self-expanding stent, which needs to cooperate with the delivery sheath to be transported to the stenotic vascular lesion area of ​​the patient. After the delivery sheath is withdrawn, the aforementioned self-expanding stent is opened to achieve The purpose of stretching the blood vessels, therefore, this expansion method is less flexible and usually causes greater irritation to the blood vessels

However, the preparation of medical devices generally has relatively high requirements on materials. The materials produced by 3D printing are often due to the selection of different materials, inappropriate binders selected during molding, and poor control of process parameters, which will lead to blanks. Defects such as fuzzy body surface, warping deformation, size deformation, stepped surface, microstructure defects, fragmentation, and mislayering are fatal hazards for the use of 3D printing technology in the manufacture of medical devices

And because the product still shrinks and deforms during the sintering process, it is difficult to control the dimensional accuracy of the product

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