Cutting method and device for bracket pipe

Abstract

The present application provides a method and device for cutting a stent tube, the cutting method comprising: respectively sleeve a first tube and a second tube on both ends of a connector; pressurizing the connector so that the connector forms an interference fit combined structure with the first tube and the second tube; fixing the combined structure, and cutting the first tube and / or the second tube in the combined structure. The method and device for cutting a stent tube provided in the present application connect the first tube and the second tube evenly by means of pressure expansion of the connector, which can effectively improve the utilization rate of the stent tube and save production costs.

Description

Technical Field

[0001] The present application belongs to the field of medical device technology, and in particular, relates to a method and device for cutting a stent tube. Background Art

[0002] The existing laser cutting machines used to cut stents basically clamp the tube first, and the protruding part extends to the laser cutting head. There is a certain distance between the two parts (generally around 120mm), which makes this section of the tube (i.e. the tailing tube) unusable. The tubes used for high-end medical device products are often very expensive. For example, the waste of tailings for heart valve stents increases the production cost. In addition, conventional welding or gluing will cause deformation of the tube, poor coaxiality, heating and degumming that affect the mechanical properties of the tube, etc., which will lead to the cut stent not being cut through, uneven waveform, and substandard mechanical properties. Stents in these conditions are unqualified products and cannot be used clinically. Summary of the invention

[0003] In response to the above technical problems, the present application provides a method and device for cutting a stent tube, which evenly connects a first tube and a second tube by means of pressure expansion of a connecting piece, thereby effectively improving the utilization rate of the stent tube and saving production costs.

[0004] The present application provides a method for cutting a stent tube, comprising:

[0005] The first pipe and the second pipe are respectively sleeved on both ends of the connecting piece;

[0006] Pressurizing the connecting piece so that the connecting piece, the first pipe and the second pipe form an interference fit combined structure;

[0007] The combined structure is fixed, and the first pipe and / or the second pipe in the combined structure is cut.

[0008] Optionally, the first pipe, the second pipe and the connecting piece are located on the same axis.

[0009] Optionally, the step of sleeve-arranging the first pipe and the second pipe at two ends of the connector respectively includes:

[0010] determining a centerline of the connector;

[0011] One end of the first tube and one end of the second tube are passed through two ends of the connector respectively and aligned along the center line.

[0012] Optionally, pressurizing the connecting member comprises:

[0013] The connecting piece is pressurized by at least one of pneumatic pressurization, hydraulic pressurization, and extrusion.

[0014] Optionally, the step of pressurizing the connecting member further comprises:

[0015] The connecting piece and the pressurizing device are connected via a quick-change joint, and the pressurizing device is used to increase the pressure on the connecting piece.

[0016] Optionally, the method further includes:

[0017] When the length of the first pipe and / or the second pipe is less than or equal to a preset value, the connecting piece is depressurized.

[0018] Optionally, fixing the combined structure and cutting the first pipe and / or the second pipe in the combined structure includes:

[0019] The combined structure is fixed on a fixture of a laser cutting machine, and the first tube and / or the second tube is cut by a laser cutter head.

[0020] The present application also provides a stent tube cutting device, which uses the stent tube cutting method as described above, and the cutting device includes a connector, a first tube, a second tube and a cutting device;

[0021] The connecting piece is a cylindrical hollow structure;

[0022] The inner diameter of the first pipe is larger than the outer diameter of the connecting piece, and the inner diameter of the second pipe is larger than the outer diameter of the connecting piece;

[0023] The cutting device includes a fixing portion and a cutting portion.

[0024] Optionally, the hardness of the connecting member is less than or equal to the hardness of the first pipe, and the hardness of the connecting member is less than or equal to the hardness of the second pipe.

[0025] Optionally, the inner diameter of the first tube is equal to the inner diameter of the second tube.

[0026] The present application provides a method and device for cutting a stent tube, and the cutting method includes: respectively sleeve the first tube and the second tube on both ends of the connector; pressurize the connector so that the connector forms an interference fit combination structure with the first tube and the second tube; fix the combination structure, and cut the first tube and / or the second tube in the combination structure. The method and device for cutting a stent tube provided by the present application connects the first tube and the second tube evenly by means of pressure expansion of the connector, which can effectively improve the utilization rate of the stent tube and save production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic flow chart of a method for cutting a stent tube provided in an embodiment of the present application;

[0028] Figure 2 This is one of the process schematic diagrams of the method for cutting a stent tube provided in an embodiment of the present application;

[0029] Figure 3 This is the second process schematic diagram of the method for cutting the stent tube provided in the embodiment of the present application;

[0030] Figure 4 This is the third process schematic diagram of the method for cutting the stent tube provided in the embodiment of the present application. DETAILED DESCRIPTION

[0031] The technical solution of the present application is further elaborated in detail below in conjunction with the accompanying drawings and specific embodiments of the specification. Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those commonly understood by technicians in the technical field of this application. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. "And / or" used herein includes any and all combinations of one or more related listed items.

[0032] First embodiment

[0033] Figure 1 This is a schematic diagram of the process of cutting the stent tube provided in the embodiment of the present application. Figure 1 This embodiment provides a method for cutting a stent tube, comprising the following steps:

[0034] Step 201: The first pipe and the second pipe are respectively mounted on two ends of the connector.

[0035] Please refer to Figure 2 , take the case where the first pipe is the tailing pipe 1 and the second pipe is the new pipe 3 as an example. First, make a connector 2 with a length of about 20 mm. The outer circle of the connector 2 is divided into half according to the corresponding grade matching tolerance to form a gap assembly with the tailing pipe 1 and the new pipe 3, and the end of the tailing pipe 1 is aligned with the end of the new pipe 3. Among them, the inner diameter of the tailing pipe 1 is larger than the outer diameter of the connector 2, and the inner diameter of the new pipe 3 is larger than the outer diameter of the connector 2. Optionally, the difference between the outer diameter of the connector 2 and the inner diameters of the tailing pipe 1 and the new pipe 3 is between 0.05mm-0.10mm. The connector 2 is coaxially matched with the tailing pipe 1 and the new pipe 3 so that the tailing pipe 1, the new pipe 3 and the connector 2 are located on the same axis.

[0036] Optionally, the inner diameter of the tailings pipe 1 is equal to the inner diameter of the new pipe 3 , so that the tailings pipe 1 and the new pipe 3 can be deformed synchronously and evenly with the expansion of the connector 2 .

[0037] Optionally, the first pipe and the second pipe are respectively sleeved on both ends of the connector, including:

[0038] Determine the centerline of the connector;

[0039] Pass one end of the first tube and one end of the second tube through the two ends of the connector respectively and align them along the center line.

[0040] Specifically, the midpoint of the connector 2 along the length direction can be marked, half of the connector 2 is inserted into the tailing pipe 1, and the other half is inserted into the new pipe 3, so that the tailing pipe 1 and the second pipe 2 each occupy half the length of the connector 2.

[0041] Step 202: Pressurize the connector to form an interference fit structure with the first pipe and the second pipe.

[0042] Please refer to Figure 3 , after the connector is compressed, its outer wall expands outwards and fits tightly with the tail material pipe 1 and the new pipe 3 respectively. The connector 2 is evenly expanded by quantitative pressurization, so that a certain degree of interference fit is formed between the tail material pipe 1, the new pipe 3 and the connector 2. At the same time, the connector 2 has good torsion resistance, which not only realizes the coaxial and positioning docking between the tail material pipe and the new pipe, but also ensures sufficient torque requirements when cutting the pipe, preventing the subsequent stent from producing incomplete or uneven waveforms during cutting. The cutting method of this embodiment does not use chemical adhesives, so as to prevent chemical adhesives from affecting the surface quality of the stent pipe, making it difficult to remove later. If the cleaning is not thorough, the stent will carry chemical poisons, which will bring hidden dangers to the subsequent implanted valve products.

[0043] Specifically, the connector 2 can be pressurized by at least one of pneumatic pressurization, hydraulic pressurization, and extrusion, so that the connector 2 is uniformly expanded to maintain the stability of the physical and chemical properties of the stent pipe. Among them, the connector 2 is a cylindrical hollow structure. One end of the connector 2 can be provided with an opening, and the small hole of the connector 2 and the quick-change joint 4 are connected by a small tube or a seamless steel pipe. It can be connected by thread or welding, and ensure good sealing. When the connector 2 has an opening at only one end, the opening end of the connector 2 can be the end of the tail material pipe 1 or the end of the new pipe 3. In the case where the new pipe is relatively long, the quick-change joint 4 can be selected to be connected at one end of the tail material pipe, so that the quick-change joint 4 is exposed at one end of the tail material pipe, which is convenient for subsequent pressurization or pressure relief operations. If the space of the cutting device is insufficient, the quick-change joint 4 can be selected to be connected at one end of the new pipe for pressurization and pressure relief. Then the pressurization equipment is connected through the quick-change joint, and gas or liquid is introduced into the connector 2 to pressurize and expand it. Of course, the two ends of the connector 2 can also be directly squeezed to cause it to deform and expand.

[0044] Step 203: fix the combined structure, and cut the first pipe and / or the second pipe in the combined structure.

[0045] Please refer to Figure 3 , fix the combined structure consisting of the tail material pipe 1, the connector 2 and the new pipe 3 on the fixture 5 of the laser cutting machine, and cut the tail material pipe 1 and / or the new pipe 3 by the laser cutter head 6. Specifically, the connected combined structure is clamped on the fixture platform of the laser cutting machine, and the normal cutting operation is performed. When the length of the connector 2 is 20mm, the tail material pipe (the first pipe 3) is connected to the connector 2 by only about 10mm, and the final remaining length of the tail material pipe will be reduced to the greatest extent, greatly improving the utilization rate of the tail material pipe.

[0046] Optionally, the cutting method further comprises:

[0047] When the length of the first pipe and / or the second pipe is less than or equal to a preset value, the pressure of the connecting piece is released to separate the connecting piece, the first pipe and the second pipe.

[0048] In this embodiment, the length of the tail material pipe 1 and / or the new pipe 3 is less than or equal to the preset value, and the preset value can be set to the length of a finished bracket. When the remaining length of the bracket pipe is not enough to cut out a complete bracket, the connector 2 can be restored to its original shape by pressure relief, and the tail material pipe 1 and the new pipe 3 can be separated from the connector 2. This process does not require heating or shrinking the bracket pipe, avoiding the change of the mechanical properties of the bracket pipe itself due to heating or shrinking, thereby affecting the final quality of the bracket. It should be noted that the pressure relief method should correspond to the pressurization method in step 202. For example, when the pressurization method is air pressure or hydraulic pressurization, the small hole of the connector 2 and the quick-change connector 4 can be connected through a small tube or a seamless steel pipe, and then the pressure relief device is connected through the quick-change connector to discharge the gas or liquid used for pressurization in the connector 2, so that the connector 2 returns to its original shape. It should be understood that in this embodiment, a pressurization and pressure relief integrated device can be used to reduce the hardware equipment involved in the processing process. Correspondingly, if the connecting member 2 is pressurized by means of extrusion deformation, it is sufficient to remove the extrusion force acting on the connecting member 2.

[0049] Optionally, the hardness of the connecting member is less than or equal to the hardness of the first pipe, and the hardness of the connecting member is less than or equal to the hardness of the second pipe.

[0050] In this embodiment, the hardness of the material of the connecting member 2 is lower than that of the bracket tube, and the difference is preferably above HB50 to avoid damaging the inner hole surface of the bracket tube.

[0051] For example, the tail pipe 1, the connector 2 and the new pipe 3 are injected with gas or liquid through the quick-change joint 4, so that the connector 2 expands evenly, and the three are connected into one body in the form of interference fit, and then the assembly is clamped on the fixture 5 of the laser cutting machine, and the laser cutter head 6 performs normal production cutting. The specific operation steps are:

[0052] 1. The initial outer diameter of the connector 2 should be smaller than the inner diameter of the bracket pipe (determined according to different types of pipes), and the length should be about 20 mm. A line should be drawn in the middle of the connector 2 to ensure that the assembly lengths at both ends are equal. One end of the connector 2 is connected to the quick-change connector 4 through a small tube to ensure that the quick-change connector 4 is exposed at the other end of the tail pipe 1 after assembly, which is convenient for subsequent pressurization or pressure relief operations.

[0053] 2. Press the tail pipe 1, connector 2 and new pipe 3 Figure 2 The quick-change connector 4 is used to connect gas or liquid and control a certain pressure value. The connector is expanded under pressure to form an expanded state as shown in FIG. Figure 3 The combined structure shown.

[0054] 3. Clamp the assembly on the fixture 5 of the laser cutting machine, and perform normal production cutting with the laser cutter head 6. Since there is a centerline mark point exposed in the middle of the connector 2, which is visible to the naked eye, it can not only prevent the laser cutter head 6 from cutting the connector 2, but also determine whether the tail pipe 1 at one end of the connector 2 needs to be replaced according to the remaining length of the tail pipe 1 and the required length of the bracket during cutting. Finally, when the remaining length of the tail pipe 1 is not enough to cut a complete bracket, the pressure is released through the quick-change joint 4, so that the connector 2 retracts to its original shape and the tail pipe 1 is removed.

[0055] The invention realizes the reasonable docking of the tail material pipe and the new pipe, has high coaxiality, good torsion resistance and does not affect the various properties of the pipe, the connector can be reused, has few steps and is easy to operate. It can realize uniform elastic expansion after pressurization and restore to the original shape after pressure relief.

[0056] The present invention greatly improves the utilization rate of raw materials and saves production costs. The length of each pipe used for cutting the stent is usually controlled to be less than 1000 mm, and the remaining length of each tailing pipe after normal cutting is generally about 120 mm. By adopting the process measures of the present invention, the length of the tailing pipe can be reduced to about 20 mm, which can improve the pipe utilization rate by more than 10%.

[0057] The method and device for cutting the stent tube provided in the embodiment of the present application include: respectively sleeve the first tube and the second tube on both ends of the connecting piece; pressurizing the connecting piece so that the connecting piece forms an interference fit combined structure with the first tube and the second tube; fixing the combined structure, and cutting the first tube and / or the second tube in the combined structure. The method and device for cutting the stent tube provided in the embodiment of the present application connects the first tube and the second tube evenly by means of the pressure expansion of the connecting piece, which can effectively improve the utilization rate of the stent tube and save production costs.

[0058] Second embodiment

[0059] In this embodiment, the tailings and new pipes of nickel-titanium alloy are selected with outer diameter of 8 mm and wall thickness of 0.5 mm. The specific operation steps are as follows:

[0060] 1. Make a copper alloy connector with an outer diameter of 6.90-6.95mm. 2. Connect the connector and the quick-change joint together through a small copper tube or a seamless steel tube. The connection can be made by thread or welding, and ensure good sealing.

[0061] 2. Pre-assemble the nickel-titanium alloy tailings pipes, connectors and new pipes;

[0062] 3. Use the quick-change joint to ventilate and pressurize the connector to 0.06MPa, and check the interference fit of the three. The outer diameter of the pipe can be measured with a vernier caliper or a slight torsion test can be performed to verify the interference fit.

[0063] 4. Clamp the combination of the three on the fixture of the laser cutting machine, and use the laser cutter head to perform normal production cutting. Finally, when the remaining length of the tail pipe is less than 20mm, release the pressure through the quick-change joint, so that the connector retracts to its original shape and the tail pipe is removed.

[0064] Third embodiment

[0065] In this embodiment, the tailing pipe and new pipe of cobalt-chromium alloy are selected with outer diameter of 29mm and wall thickness of 0.6mm. The specific operation steps are as follows:

[0066] 1. Make nylon connectors with an outer diameter of 27.70-27.75mm, and connect the connectors and quick-change connectors together through small copper tubes or seamless steel tubes. They can be connected by threads or snaps, and ensure good sealing.

[0067] 2. Pre-assemble the tailings pipes, connectors and new pipes of cobalt-chromium alloy;

[0068] 3. Use the quick-change joint to ventilate and pressurize the connector to 0.1MPa to check whether the three are interference fit. The outer diameter of the pipe can be measured with a vernier caliper or a slight torsion test can be performed to verify the interference fit.

[0069] 4. Clamp the combination of the three on the fixture of the laser cutting machine, and use the laser cutter head to perform normal production cutting. Finally, when the remaining length of the tail pipe is less than 20mm, release the pressure through the quick-change joint, so that the connector retracts to its original shape and the tail pipe is removed.

[0070] Fourth embodiment

[0071] This embodiment provides a stent tube cutting device, which uses the stent tube cutting method in any of the above embodiments.

[0072] The cutting device of the stent tube comprises a connecting piece, a first tube, a second tube and a cutting device;

[0073] The connecting piece is a cylindrical hollow structure, and at least one end of the connecting piece is provided with an opening;

[0074] The inner diameter of the first pipe is larger than the outer diameter of the connecting piece, and the inner diameter of the second pipe is larger than the outer diameter of the connecting piece;

[0075] The cutting device includes a fixing portion and a cutting portion.

[0076] Optionally, the hardness of the connecting member is less than or equal to the hardness of the first pipe, and the hardness of the connecting member is less than or equal to the hardness of the second pipe.

[0077] Optionally, the inner diameter of the first tube is equal to the inner diameter of the second tube.

[0078] For the specific application method of the cutting device for the stent tube in this embodiment, please refer to the first to fourth embodiments, which will not be described in detail here.

[0079] The above embodiments are merely illustrative of the principles and effects of the present application and are not intended to limit the present application. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed in the present application shall still be covered by the claims of the present application.

Claims

1. A method for cutting a stent tube, characterized in that: include: The first pipe and the second pipe are respectively sleeved on both ends of the connecting piece, the connecting piece is a cylindrical hollow structure, one end of the connecting piece is provided with an opening, the difference between the outer diameter of the connecting piece and the inner diameter of the first pipe and the second pipe is between 0.05mm and 0.10mm, the material hardness of the connecting piece is HB50 lower than the material hardness of the first pipe and the second pipe, and the connecting piece is a copper alloy connecting piece; Pressurizing the connector by at least one of pneumatic pressurization, hydraulic pressurization, and extrusion, so that the connector, the first pipe, and the second pipe form an interference fit combined structure; Fixing the combined structure, and cutting the first pipe and / or the second pipe in the combined structure; The method of sleeve-arranging the first pipe and the second pipe at two ends of the connecting piece respectively comprises: determining a centerline of the connector; Pass one end of the first pipe and one end of the second pipe through two ends of the connector respectively and align them along the center line; Fixing the combined structure on a fixture of a laser cutting machine, and cutting the first tube and / or the second tube by a laser cutter head; When the length of the first pipe and / or the second pipe is less than or equal to a preset value, the connecting piece is depressurized.

2. The cutting method according to claim 1, characterized in that: The first pipe, the second pipe and the connecting piece are located on the same axis.

3. The cutting method according to claim 1, characterized in that: The step of pressurizing the connecting member further comprises: The connecting piece and the pressurizing device are connected via a quick-change joint, and the pressurizing device is used to increase the pressure on the connecting piece.

4. A cutting device for a stent tube, characterized in that: The method for cutting the stent tube according to any one of claims 1 to 3 is applied, wherein the cutting device comprises a connector, a first tube, a second tube and a cutting device; The connecting piece is a cylindrical hollow structure; The inner diameter of the first pipe is larger than the outer diameter of the connecting piece, and the inner diameter of the second pipe is larger than the outer diameter of the connecting piece; The cutting device includes a fixing portion and a cutting portion.

5. The cutting device according to claim 4, characterized in that The hardness of the connecting member is less than or equal to the hardness of the first pipe, and the hardness of the connecting member is less than or equal to the hardness of the second pipe.

6. The cutting device according to claim 4, characterized in that The inner diameter of the first pipe is equal to the inner diameter of the second pipe.

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