CN111805108A

CN111805108A - Medical guide wire and method for welding and forming head end thereof

Info

Publication number: CN111805108A
Application number: CN201910290524.1A
Authority: CN
Inventors: 卢政; 王美贤; 姜鹏辉; 谭家宏
Original assignee: Microport Longmai Medical Technology Jiaxing Co ltd
Current assignee: Microport Longmai Medical Technology Jiaxing Co ltd
Priority date: 2019-04-11
Filing date: 2019-04-11
Publication date: 2020-10-23

Abstract

The invention discloses a medical guide wire and a method for welding and forming the head end of the medical guide wire, wherein the head end of the medical guide wire is provided with an inner core component, the inner core component is sleeved with a spring coil, and the spring coil is connected with the inner core component of the medical guide wire through welding, and the method comprises the following steps: s1: coating a flow resisting agent on the surface of the spring coil; s2: placing the spring coil coated with the flow resisting agent in a capillary cavity, so that the capillary cavity wraps the spring coil; s3: coating a soldering flux at the head end of the spring coil and coating a solder at the head end of the inner core structure; s4: heating the solder to a melting state, wherein under the capillary action of the capillary action cavity, one part of the solder permeates into the spring coil, and the other part of the solder is gathered at the head end of the inner core structure; and S5, cooling the solder to a solidification state, wherein the solder at the head end of the inner core structure directly forms a smooth ball head. The problems that the welding appearance of the head end of the guide wire is difficult to control, the length of a welding spot is too long, and impurities which are difficult to remove are introduced during welding are solved.

Description

Medical guide wire and method for welding and forming head end thereof

Technical Field

The invention relates to a medical instrument, in particular to a medical guide wire and a method for welding and forming a head end of the medical guide wire.

Background

The medical guide wire commonly used for treating various vascular diseases has certain controllability, and the head end of the medical guide wire enters the flexibility and the recovery of a tortuous vessel. After entering a human vascular system, the guide wire reaches a target lesion position through the vascular system, the human vascular system can be a very tortuous channel, in order to enable the medical guide wire to smoothly pass through a blood vessel, a guide wire body rod needs to have certain flexibility, and the guide wire head end needs to have proper head end hardness and good tactile feedback. Compared with the commonly used medical guide wire, the end position of the spring coil is connected with the guide wire inner core component by tin soldering, and the end after tin soldering has higher welding spot fracture connection strength. In the conventional head-end soldering technique, the molten solder activates the activity of the flux, and the solder is in the form of a low-viscosity liquid. The tin liquid is easy to freely flow and fill along gaps in the pitch of the spring coil, and head end welding spots are difficult to form. Therefore, the head end soldering molding technology is a relatively important difficulty in the manufacturing and production of the medical guide wire.

In the published patent EP1455883B1, a heat shrinkable tube is used to cover the wire guide shaft, a certain amount of soldering flux is coated at the position of the head end, a heat source is arranged near the solder ball after the solder ball is placed, and the solder ball is heated to a molten state, thereby completing the welding of the head end. The heat shrinkable tube adopted in the method is a polyolefin heat shrinkable tube which can prevent the flowing of soldering flux and molten tin, but the material has a low melting point, and the heat shrinkable tube is adhered to a wire guide shaft after being melted and is difficult to remove when the head end of the heat shrinkable tube is soldered. In addition, molten tin material flows freely in the gap position of the spring coil, and the length of tin soldering at the head end of the guide wire is easily inconsistent when the guide wire finished product is produced in batches.

Disclosure of Invention

The invention aims to solve the technical problems that a medical guide wire and a head end tin soldering forming method thereof are provided, and the problems that the tin soldering appearance of the head end of the guide wire is difficult to control, the length of a welding point is too long, and impurities which are difficult to remove are introduced during welding are solved.

The technical scheme adopted by the invention for solving the technical problems is to provide a method for welding and forming the head end of a medical guide wire, wherein the head end of the medical guide wire is provided with an inner core component, the inner core component is sleeved with a spring coil, and the spring coil is connected with the inner core component through welding, and the method comprises the following steps: s1: coating a flow resisting agent on the surface of the spring coil; s2: placing the spring coil coated with the flow resisting agent in a capillary cavity, so that the capillary cavity wraps the spring coil; s3: coating a soldering flux at the head end of the spring coil and coating a solder at the head end of the inner core structure; s4: heating the solder to a melting state, wherein under the capillary action of the capillary action cavity, one part of the solder permeates into the spring coil, and the other part of the solder is gathered at the head end of the inner core structure; and S5, cooling the solder to a solidification state, wherein the solder at the head end of the inner core structure directly forms a smooth ball head.

Preferably, the inner diameter of the capillary cavity is 0.02-0.06 mm larger than the outer diameter of the spring coil.

Preferably, the capillary chamber is a glass capillary.

Preferably, the temperature resistance level of the capillary cavity is above 300 ℃.

Preferably, in step S3, the solder is heated at a first heating position located at a port of the capillary cavity near the solder.

Preferably, in step S3, the solder is heated at a second heating location, which is located at a port of the capillary cavity away from the solder.

Preferably, the solder is a tin material.

Preferably, the flow blocker comprises a metal oxide; the flux includes a halide.

The invention also provides a medical guide wire which comprises a head end, wherein the head end is formed by welding through the method.

Compared with the prior art, the invention has the following beneficial effects: according to the medical guide wire and the method for welding and forming the head end of the medical guide wire, the flow resisting agent is coated on the adjacent area of the position to be welded of the spring coil, so that the free flowing and infiltration of the solder liquid in a molten state are effectively prevented, and the phenomenon that the welding point at the head end of the guide wire is too long and stiff is avoided; in addition, the guide wire is arranged in the capillary action cavity, particularly in the glass capillary tube, molten solder liquid can directly form a smooth ball head in the capillary tube due to the action of liquid surface tension during welding, secondary polishing is not needed, the glass capillary tube replaces a heat shrink tube for welding, and the molten heat shrink tube is prevented from remaining on the guide wire.

Drawings

Fig. 1 is a schematic view of a tip end of a medical guidewire coated with a flow inhibitor according to an embodiment of the invention;

FIG. 2 is a schematic view of the tip of a medical guidewire after being inserted into a capillary and heated;

fig. 3 is a schematic view of the medical guide wire with the head end soldered according to the embodiment of the invention.

In the figure:

1 guide wire, 2 capillary and 3 tin materials

4 first heating position 5 second heating position 11 core member

31 ellipsoidal ball head of 12 spring coil 13 flow resisting agent

Detailed Description

The invention is further described below with reference to the figures and examples.

Fig. 1 is a schematic view of a medical guidewire tip coated with a flow blocking agent according to an embodiment of the invention.

The head end of the medical guide wire provided by the invention is provided with an inner core component 11, the inner core component 11 is sleeved with a spring coil 12, the spring coil 12 is connected with the inner core component 11 of the medical guide wire 1 through welding, the solder of the embodiment mainly takes tin material 3 (such as solder ball or tin wire) as an example, the welding temperature can be prevented from being overhigh and the influence on the physical property of the material of the spring coil 12 can be avoided by adopting tin soldering (the front end spring is platinum-nickel, the melting point is lower than 470 ℃), and the tin material 3 can be silver-tin or gold-tin alloy. The concrete implementation steps of head end tin soldering forming are as follows:

first, referring to fig. 1, a flow blocking agent 13 is coated on the surface of the spring coil 12 adjacent to a position to be welded. The flow resisting agent 13 can block the free flow of tin liquid, and the tin liquid is coated on the surface of the spring coil 12 which does not need to be soldered, so that the formation of a solder joint at the coating position can be avoided, and the length of the soldered solder joint can be controlled. In other embodiments, the flow inhibitor 13 may also be replaced by other metal oxide powder or other glass ceramic powder that can effectively prevent soldering, is easy to clean, and has a temperature resistance level of 350 ℃ or higher, preferably magnesium oxide powder, and the flow inhibitor can effectively prevent penetration of molten tin due to free flow of molten tin, so as to facilitate soldering of spring coils with a controlled number of pitches.

Next, referring to fig. 2, the spring coil 12 coated with the flow resisting agent 13 is inserted into the capillary cavity, so that the capillary cavity wraps the spring coil 12; the capillary cavity is a glass capillary tube or a sleeve which can resist temperature of more than 300 ℃ and is not easy to melt, a coating material and the like; the present embodiment will be described mainly by taking the glass capillary 2 as an example. Preferably, the inner diameter of the glass capillary 2 is 0.02 to 0.06mm larger than the outer diameter of the spring coil 12. Because the existence of the glass capillary tube 2, the tin material solidified outside the spring coil after welding is limited in a certain size range, and the overlarge outer diameter size of the spring coil after tin welding is avoided.

Finally, referring to fig. 2 and 3, a soldering flux is applied to the position to be soldered of the spring coil 12 in the glass capillary 2, the soldering flux can assist and promote the soldering process, and has the functions of protecting and preventing oxidation reaction, the main component of the soldering flux is an active agent containing halide, not limited to solid, liquid or gaseous, preferably zinc chloride solution, the tin 3 is put into the head end part of the inner core structure 11, the tin 3 can be blown by a hot air blower at the first heating position 4 or heated by an electric iron at the second heating position 5, and the first heating position 4 is located at the nozzle of the glass capillary 2 far away from the tin 3; the second heating position 5 is located at the glass capillary 2 near the orifice of the solder 3. After being fully heated, the solid tin material 3 is melted and converged at the position of the wire guide head in the glass capillary tube 2, the tin liquid permeates into the spring coil 12 for a certain distance, redundant tin liquid which does not permeate into the spring coil 12 is converged at the position of the head end of the inner core structure 11, the molten tin liquid becomes thinner at two sides and is protruded in the middle due to the surface tension action of capillary action liquid, the ellipsoidal ball head 31 in smooth transition is directly formed after cooling, one part of redundant tin liquid is contacted with the inner wall of the glass capillary tube 2, and the tin liquid cannot be adhered to the surface of the glass tube. As shown in fig. 3. The ellipsoidal ball head with smooth transition of the head end of the spring coil is formed mainly by utilizing the surface tension action of molten tin.

In conclusion, the medical guide wire provided by the invention can not introduce other impurities which are difficult to remove under the participation of the glass capillary 2, the head end forming is completed by utilizing the surface tension effect of liquid tin material in the glass capillary 2, and the flow resisting agent 13 is coated on the outer side of the spring coil 12, so that the free flow of the tin liquid is effectively prevented, and the problem of overlong welding spot size is avoided. Therefore, the problems that the tin soldering appearance of the head end of the guide wire is difficult to control, the length of a welding point is too long, impurities which are difficult to remove are introduced during welding and the like are solved. Has the following advantages:

(1) the guide wire 1 is arranged at the inner side of the glass capillary tube 2, and molten tin can directly form a smooth soldering ball head in the glass capillary tube 2 due to the capillary action during soldering without being polished again.

(2) The adjacent area of the position to be welded of the spring coil 12 is coated with the flow resisting agent 13, so that the free flowing and infiltration of tin liquid in a molten state are effectively prevented, and the phenomenon that the welding point at the head end of the guide wire is too long and stiff is avoided.

(3) The capillary glass tube is used for welding instead of the heat shrinkable tube, so that the molten heat shrinkable tube component is prevented from remaining on the guide wire 1.

Although the present invention has been described with respect to the preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A method for welding and forming a head end of a medical guide wire is characterized by comprising the following steps of:

s1: coating a flow resisting agent on the surface of the spring coil;

s2: placing the spring coil coated with the flow resisting agent in a capillary cavity, so that the capillary cavity wraps the spring coil;

s3: coating a soldering flux at the head end of the spring coil and coating a solder at the head end of the inner core structure;

s4: heating the solder to a melting state, wherein under the capillary action of the capillary action cavity, one part of the solder permeates into the spring coil, and the other part of the solder is gathered at the head end of the inner core structure;

and S5, cooling the solder to a solidification state, wherein the solder at the head end of the inner core structure directly forms a smooth ball head.

2. The method for welding and forming the head end of the medical guide wire according to claim 1, wherein the inner diameter of the capillary cavity is 0.02-0.06 mm larger than the outer diameter of the spring coil.

3. The method for welding and forming the tip of the medical guide wire according to claim 1, wherein the capillary cavity is a glass capillary.

4. The method for welding and forming the tip of the medical guide wire according to claim 1, wherein the capillary cavity has a temperature resistance level of 300 ℃ or higher.

5. The method for tip solder molding of a medical guidewire as set forth in claim 1, wherein the step S3 heats the solder at a first heating location located in the capillary cavity near a port of the solder.

6. The method for tip solder molding of a medical guidewire as set forth in claim 1, wherein the solder is heated at a second heating location at a port of the capillary cavity remote from the solder in step S3.

7. The method for welding and forming the head end of the medical guide wire according to claim 1, 5 or 6, wherein the solder is tin material.

8. The method for welding and forming the tip end of the medical guidewire according to claim 1, wherein the flow inhibitor comprises a metal oxide; the flux includes a halide.

9. A medical guide wire comprising a tip, wherein the tip is welded by the method of any one of claims 1-8.