RU2727031C1 - Method of manufacturing a vascular implant from alloys with shape memory effect braided with a single thread - Google Patents

Abstract

FIELD: medicine.SUBSTANCE: invention refers to medicine, namely to X-ray endovascular dilatation. A method for manufacturing a vascular implant from alloys with shape memory effect woven with a single thread involves automated braiding of the implant on the mandrel with a modified winding machine according to a given algorithm. During braiding, the wire thread extends from one end of the future article to the other at an angle providing for thread mixing at each approach to the end of the mandrel and cross weaving of the thread at points of intersection in the plane of the mandrel surface, thermomechanical treatment in vacuum medium to ensure memorization of mold and reliable protection against oxidation or nitriding of article in two stages: at first annealing is carried out on mandrel, on which braiding was performed, end expanders are screwed on the mandrel to increase the diameter of the product ends, followed by the second annealing step, removing the article from the mandrel, then the product is subjected to ultrasonic cleaning in the alcohol bath.EFFECT: invention is characterized by that the braided article has two ends of the wire thread.1 cl

Description

The invention relates to medicine, namely to X-ray endovascular dilation. The objective of the invention is to provide a method for machine weaving of a vascular implant from a single thread for automating production, reducing the cost of a product unit and increasing the volume of production.

There is a known method of manufacturing a self-expanding peripheral stent from an alloy based on titanium nickelide with a modified surface (RF Patent RU 2633639 C1 IPC A61F 2/82, publ. 16.10.2017), including manufacturing by laser cutting from a titanium nickelide billet, thermomechanical processing, cleaning and modification of the stent surfaces with accelerated silicon ions, while the thermomechanical treatment is carried out by successive annealing of the workpiece on cylindrical mandrels with a stepwise increase in the diameter of the mandrels, while the increase in the diameter of the stent workpiece when moving from one mandrel to another is 20 ÷ 50%.

The disadvantages of this method include large time and energy costs in obtaining products with a relatively large final diameter, so to obtain a product with a diameter of 10 mm, 6 annealing is assumed to be carried out on various mandrels, while products in practice may require a diameter of up to 35 mm.

A device for the manufacture of stent elements of a stent graft from nitinol wire is known (Patent of the Republic of Belarus BY 9887 U 2013.10.30, IPC A61F 2/06, publ. 03/25/2013), using a drum mounted on a support with protruding mandrels on the cylindrical surface of the drum serving to form the required stent profile by pulling a wire between stationary mandrels, according to the utility model, protruding mandrels on the cylindrical surface of the drum are made in the form of two systems of radial pins with their displacement by half a step relative to each other in each of the systems located in parallel planes relative to each other at a distance equal to the distance between two opposite vertices of the zigzag profile of the stent element, while the device is equipped with a means for calibrating the stretching of the stent elements of the stent graft and a means for heat fixing the uninhibited zigzag shape of the stent element.

The device is designed for the manufacture of a wide catalog number, but as a disadvantage, it can be noted that the maximum diameter of the resulting products is 16 mm, which does not cover the full need for the diameters of such products.

Closest to the proposed invention is a method of forming a self-expanding stent (RF Patent RU 2593980 C2, IPC A61F 2/90, publ. 10.10.2013) containing in its essence the formation of the first end of the stent by forming the first bend in each of the many threads, each of which includes a portion of the thread on both sides of the first bend of the thread, with each portion of the thread having an end. Thereafter, the thread parts are woven, with each end of the thread parts located near the second end of the stent after the thread parts are weaving. Then heat treatment of the plurality of yarns for a first period of time after the weaving of the yarn parts. Thereafter, the second end of the stent is formed by forming a second bend of each of the plurality of filaments, and the plurality of filaments are heat treated for a second period of time after the formation of the second bends.

This invention makes it possible to manufacture implants of various sizes, which, in turn, due to the lack of rigid fixation of the places of interweaving of the wire threads, reduce the effect on the implant of alternating loads on bending and compression-expansion during operation. However, the proposed product consists of many threads, which in turn complicates the production of additional multiple soldering of the connections of the ends of the threads or the use of connecting elements.

The object of the invention is to provide a method for the automated manufacture of a vascular implant from a thin wire thread with a shape memory effect, namely stents and Kava filters based on stents.

The technical result is a braided product with two ends of the wire thread.

The technical result is achieved by the fact that in the method of manufacturing a vascular implant from shape memory alloys, woven with a single thread, consisting of automated weaving of the implant onto a mandrel by a modified winding machine according to a given algorithm, when weaving, the wire thread goes from one end of the future product to another at an angle providing mixing of the thread at each approach to the end of the mandrel and cross-weaving of the thread at the intersection points in the plane of the mandrel surface, thermomechanical processing in a vacuum environment to ensure shape memory and reliable protection against oxidation or nitriding of the product, in two stages, at the first annealing is carried out on the mandrel , on which weaving was carried out, then end expanders are screwed onto the mandrel to increase the diameter of the ends of the product, followed by the second stage of annealing, the product is removed from the mandrel, then the product is subjected to ultrasonic cleaning in an alcohol bath. Weaving is carried out from one strand of wire, which is considered more optimal, since the number of ends is limited to two, and therefore, there is no need for multiple soldering or bonding as in the prototype. After weaving, both ends of the wire are set into the weaving of the product and do not cause inconvenience during installation and operation of the product. According to the invention, the manufacture of a vascular implant is carried out in 4 stages. At the first stage, an automated weaving of the implant onto a mandrel is carried out by a modified winding machine according to a given algorithm, so that when weaving, the wire thread goes from one end of the future product to another at an angle and is wound by the hook on the mandrel, and the number of hooks must be strictly odd, this ensures mixing threads at each approach to the end face of the mandrel and cross-weaving of the thread at the intersection in the plane of the mandrel surface, after the ends of the wire are tucked into the weaving. Next, thermomechanical processing is carried out in a vacuum environment to ensure shape memory and with reliable protection against oxidation or nitriding of the product in two stages, at the first, annealing is carried out on the mandrel on which the weaving was performed, after that end expanders are screwed onto the mandrel to increase the diameter of the ends of the product, followed by the second stage of annealing, remove the product from the mandrel. The last step is ultrasonic cleaning in an alcohol bath to remove any impurities that may have been produced during manufacture.

The resulting product can have different dimensions, which depend only on the need. The dimensions are set by the mandrel and the braiding program. A modified winding machine means a standard automated machine for winding woven yarns prepared for weaving with fine wire.

An example of a specific implementation of the invention:

Weaving was carried out with a wire of the TiNbTaZr composition with shape memory. The required dimensions of the product were given by the task of using the resulting product as part of the catching product Kava filter. The diameter was 30 mm, the length was 30 mm. The thread was fixed on the mandrel from one end, the number of hooks on each side was 11. The rotation speed of the machine shaft was set by the program of 12 rpm. After completing the program, the ends of the wire are manually threaded into the braid so that they cannot damage the walls of the vascular system.

Next, the braided product, together with the mandrel, was placed in a vacuum oven and annealed at a temperature of 600 ° C and annealed for 15 minutes. Then, the elements expanding the edges of the product were put on the ends of the mandrel, and they were again placed in a vacuum furnace and annealed at a temperature of 600 ° C and annealed for 15 minutes.

After that, the expanding elements were removed and the product was removed, placed in an ultrasonic bath with alcohol to clean it from contaminants that could be obtained at the time of weaving, annealing or contact with the operator.

Thus, the proposed invention makes it possible to obtain vascular implants in mass quantities, automating the binding part of the work, which is labor-intensive.

Claims (1)

A method of manufacturing a vascular implant from shape memory alloys, woven with a single thread, including automated weaving of the implant on a mandrel by a modified winding machine according to a given algorithm, characterized in that when weaving, the wire thread goes from one end of the future product to another at an angle that ensures mixing of the thread at each approach to the end of the mandrel and cross-weaving of the thread at intersections in the plane of the mandrel surface, thermomechanical processing in a vacuum environment to ensure shape memory and reliable protection against oxidation or nitriding of the product in two stages: at the first, annealing is carried out on the mandrel on which the weaving was performed , then end expanders are screwed onto the mandrel to increase the diameter of the ends of the product, followed by the second stage of annealing, the product is removed from the mandrel, then the product is subjected to ultrasonic cleaning in an alcohol bath.