Valve stent heat setting mold and use method thereof

Abstract

The invention relates to the technical field of medical instruments, in particular to a valve stent heat setting mold which comprises a pre-expanding assembly and a setting assembly, the pre-expanding assembly and the setting assembly are each provided with an inlet end and a supporting part in the axial direction, and the inlet ends are constructed to be smaller than the diameter of a valve stent so that the valve stent can pass through; a positioning piece used for fixing a valve support is constructed on the supporting part, the pre-expanding assembly comprises a first pre-expanding mold, a second pre-expanding mold, a third pre-expanding mold and a fourth pre-expanding mold, and the diameters of the supporting parts of the first pre-expanding mold, the second pre-expanding mold, the third pre-expanding mold and the fourth pre-expanding mold are sequentially increased; the method has the effects of ensuring lower internal stress of the bracket structure and good heat setting effect.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to a valve stent heat-setting mold and its usage method. Background Technology

[0002] The core component of transcatheter aortic valves, mitral valves, and other interventional artificial heart valves is a self-expanding or balloon-expandable stent, typically made of shape memory materials such as nickel-titanium alloys. This stent, under radial compression, is encapsulated by the delivery system and delivered to the target location in the heart. After being released from its confinement or inflated by a balloon, it returns to a pre-set, geometrically specific unfolded state under the influence of body temperature or mechanical force, thus anchoring itself to the original valve annulus and supporting the replaced leaflet.

[0003] To ensure that the valve stent can accurately and stably recover and maintain its intended functional shape in vivo, it must undergo rigorous heat treatment during manufacturing, a process known as "heat setting." The heat setting mold is a key piece of equipment used in this heat treatment process to constrain, fix, and shape the final geometry of the stent. The mold cavity directly determines all key geometric parameters of the valve stent after full expansion, including its diameter, height, contour curve, and grid cell shape. Its design and manufacturing precision are prerequisites for ensuring the dimensional consistency, mechanical performance, and functional reliability of valve products. However, the industry-standard one-time heat setting process has inherent flaws: this process directly expands the stent from its initial state to a complex target shape through a single heating process. This drastic single deformation can easily lead to excessive internal stress and microscopic defects within the nickel-titanium alloy material, resulting in loss of dimensional accuracy or performance impairment of the valve stent.

[0004] Therefore, there is an urgent need for a thermoforming mold for valve stents to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a thermosetting mold for valve stents, which aims to solve the problems in the prior art and has the beneficial effects of ensuring low internal stress in the stent structure and good thermosetting effect.

[0006] Another object of the present invention is to provide a method for using a valve stent heat-setting mold, which is simple to operate. This invention is achieved through the following technical solution: A valve stent heat-setting mold includes a pre-expansion assembly and a setting assembly. Both the pre-expansion assembly and the setting assembly have an inlet end and a support portion in the axial direction. The inlet end is configured to be smaller than the diameter of the valve stent to allow it to pass through. The support portion is provided with a positioning element for fixing the valve stent. The pre-expansion assembly includes a first pre-expansion mold, a second pre-expansion mold, a third pre-expansion mold, and a fourth pre-expansion mold, and the diameter of the support portion of the first pre-expansion mold, the second pre-expansion mold, the third pre-expansion mold, and the fourth pre-expansion mold increases sequentially.

[0007] Preferably, the support portion is constructed as a hollow tubular structure.

[0008] Preferably, the support portion has a head, a waist, and a tail in the axial direction. Both the first and second pre-expanding molds have positioning components on their waist sections as support parts. The head, waist, and / or tail of the support portion of the third and fourth pre-expanding molds are equipped with positioning components.

[0009] Preferably, the shaping component includes a first shaping mold and a second shaping mold, wherein the support diameters of the first shaping mold and the second shaping mold are the same and larger than the support diameter of the fourth pre-expanding mold.

[0010] Preferably, the bottom of the first shaping mold is further provided with a boss, which is connected to the support part, and the outer surface of the boss is also provided with a positioning element.

[0011] Preferably, the tail portion of the support of the second shaping mold has a positioning element.

[0012] A method for heat-setting a valve stent, comprising the aforementioned heat-setting mold for the valve stent, and further comprising: S1. Install the unshaped valve stent onto the first pre-expansion mold, fix the valve stent with the positioning component, and then heat it. S2. After cooling the valve stent after the first pre-dilation treatment, install it on the second pre-dilation mold, and then heat it up. S3. After cooling the valve stent after the second pre-dilation treatment, install it on the third pre-dilation mold, and then heat it up. S4. After cooling the valve stent after the third pre-dilation treatment, install it on the fourth pre-dilation mold, and then heat it up. S5. After cooling the valve stent after the fourth pre-expansion treatment, install it on the first or second shaping mold, and then heat it up.

[0013] Compared with the prior art, the present invention has the following advantages and beneficial effects: The technical solution provided by this invention has a relatively simple overall structure, making it easy and quick to manufacture. Furthermore, the molding of the valve stent requires the use of pre-expansion and shaping components in stages. The pre-expansion component includes a first pre-expansion mold, a second pre-expansion mold, a third pre-expansion mold, and a fourth pre-expansion mold, with the diameter of the support portion of each mold increasing sequentially. Therefore, by pre-expanding the unfinished valve stent multiple times, timely adjustments and quality monitoring can be ensured during each pre-expansion, resulting in a more uniform increase in the size of each part of the valve stent structure during expansion, reducing internal stress. Finally, the shaping component completes the molding process, ensuring the valve stent has a good shaping effect and accurate dimensions. Attached Figure Description

[0014] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings: Figure 1 This is an overall schematic diagram of the first pre-expanding mold provided in an embodiment of the present invention; Figure 2 A front view of the first pre-expanded mold provided in an embodiment of the present invention; Figure 3 A front view of the second pre-expanded mold provided in an embodiment of the present invention; Figure 4 This is an overall schematic diagram of the second pre-expanding mold provided in an embodiment of the present invention; Figure 5 A front view of the third pre-expanding mold provided in an embodiment of the present invention; Figure 6 This is an overall schematic diagram of the third pre-expanding mold provided in an embodiment of the present invention; Figure 7 A schematic diagram of the back of the third pre-expanding mold provided in an embodiment of the present invention; Figure 8 A front view of the fourth pre-expanding mold provided in an embodiment of the present invention; Figure 9 This is an overall schematic diagram of the fourth pre-expanding mold provided in an embodiment of the present invention; Figure 10 A front view of the first shaping mold provided in an embodiment of the present invention; Figure 11 This is an overall schematic diagram of the first shaping mold provided in an embodiment of the present invention; Figure 12 This is a schematic diagram of the back of the first shaping mold provided in an embodiment of the present invention; Figure 13 This is an overall schematic diagram of the second shaping mold provided in an embodiment of the present invention; Figure 14 This is a schematic diagram of a valve stent installed on a pre-dilation assembly according to an embodiment of the present invention.

[0015] The attached diagram shows the markings and corresponding component names: 100-Pre-expansion component, 110-First pre-expansion mold, 120-Second pre-expansion mold, 130-Third pre-expansion mold, 140-Fourth pre-expansion mold, 200-Shaping component, 210-First shaping mold, 220-Second shaping mold, 230-Boss, 300-Inlet end, 400-Support part, 410-Head, 420-Waist, 430-Tail, 500-Positioning component, 600-Valve stent. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0017] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other instances, well-known structures, circuits, materials, or methods have not been specifically described in order to avoid obscuring the invention.

[0018] Throughout this specification, references to "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "an embodiment," "an example," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. Moreover, those skilled in the art will understand that the illustrations provided herein are for illustrative purposes and are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0019] In the description of this invention, the terms "front", "rear", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0020] Example like Figures 1-14 As shown, this embodiment provides a valve stent heat-setting mold, including a pre-expansion component 00 and a setting component 200. Both the pre-expansion component 00 and the setting component 200 have an entry end 300 and a support portion 400 in the axial direction. The entry end 300 is constructed with an arc shape, and its diameter is smaller than the diameter of the valve stent, thus facilitating the passage and installation of the valve stent on the support portion 400. The support portion 400 is constructed with multiple positioning elements 500 for fixing the valve stent, distributed according to the grid shape of the valve stent, achieving a good fixing effect. Multiple pre-expansion components 00 are provided, including at least a first pre-expansion mold 110, a second pre-expansion mold 120, a third pre-expansion mold 130, and a fourth pre-expansion mold 140, as shown... Figures 1 to 9 As shown, the diameters of the support portions 400 of the first pre-expansion mold 110, the second pre-expansion mold 120, the third pre-expansion mold 130, and the fourth pre-expansion mold 140 increase sequentially. Therefore, the diameter expansion of the valve stent can be carried out gradually, ensuring that each diameter expansion can be carried out stably, preventing damage to the structure of the valve stent itself, improving the production quality of the valve stent, and at the same time, manufacturing problems can be detected in time during multiple pre-expansion processes, ensuring the finished product quality and yield of the valve stent.

[0021] Furthermore, the support part 400 is constructed as a hollow tubular structure with a certain wall thickness to maintain the overall strength of the mold; at the same time, the hollow interior can improve the heat conduction efficiency, so that the expanded valve stent can achieve a better pre-expansion effect after heating.

[0022] Furthermore, the support portion 400 has a head 410, a waist 420, and a tail 430 in the axial direction, with the head 410 connected to the inlet end 300; the waist 420 of the support portion 400 of both the first pre-expanding mold 110 and the second pre-expanding mold 120 is constructed with positioning elements 500, such as... Figures 1 to 4 As shown, the waist 420 of both the first pre-expansion mold 110 and the second pre-expansion mold 120 is constructed with multiple positioning elements 500. Every four positioning elements 500 form a group, and the four positioning elements 500 in each group are distributed in a diamond shape, which can play a good role in fixing the grid structure on the valve stent. It should be noted that because the inner diameter of the valve stent increases after the first pre-expansion, the spacing between each group of positioning elements 500 on the second pre-expansion mold 120 is greater than the spacing between each group of positioning elements 500 on the first pre-expansion mold 110.

[0023] The head 410, waist 420, and / or tail 430 of the support portion 400 of the third pre-expanding mold 130 and the fourth pre-expanding mold 140 are provided with positioning elements 500; such as Figures 5 to 9As shown, the distribution of positioning elements 500 on the third pre-expansion mold 130 and the fourth pre-expansion mold 140 is similar. The head 410 of the support portion 400 has four positioning elements 500 per group, arranged according to the distribution of the connection holes at the bottom of the valve stent, and four groups are arranged along the axial direction of the support portion 400. The waist 420 of the support portion 400 has four rows of positioning elements 500, with five positioning elements 500 forming a group in the first row. The three middle positioning elements 500 are arranged in an inverted triangle, and two positioning elements 500 are symmetrically distributed on both sides. And along the support portion 400... There are four sets of positioning elements 500 arranged circumferentially around the support part 400; in the second row, there are also four sets of positioning elements 500 arranged circumferentially around the support part 400. Each set of positioning elements 500 has two groups of four positioning elements 500 arranged in a diamond shape. Then, on the outside of the diamond-shaped positioning elements 500, there is a group of two positioning elements 500 arranged diagonally. The two groups of positioning elements 500 arranged diagonally are also symmetrically arranged. In the third and fourth rows, there are four positioning elements 500 in each set, arranged in multiple sets circumferentially around the support part 400. The four positioning elements 500 in each set are arranged in a diamond shape.

[0024] Preferably, the shaping component 200 includes a first shaping mold 210 and a second shaping mold 220, wherein the support portions 400 of the first shaping mold 210 and the second shaping mold 220 have the same diameter and are larger than the diameter of the support portion 400 of the fourth pre-expanding mold 140; for example Figures 10 to 13 As shown, the first shaping mold 210 and the second shaping mold 220 are molds used after four pre-expansions. Therefore, the diameter of the support part 400 of the two is larger than the diameter of the support part 400 of the fourth pre-expansion mold 140. The bottom of the first shaping mold 210 is also constructed with a boss 230, which is connected to the support part 400. Its interior is also a hollow structure. At the same time, due to the setting of the boss 230, the tail part 430 of the support is combined with the structure of the boss 230. Therefore, a positioning part 500 is also constructed on the outer surface of the boss 230.

[0025] Preferably, the tail 430 of the support portion 400 of the second shaping mold 220 is equipped with a positioning element 500, such as... Figure 13 As shown, the tail 430 of the second shaping mold 220 has four positioning elements 500, which are evenly distributed; and the first shaping mold 210 and the second shaping mold 220 are used for two different valve stents, so the tail 430 is designed differently.

[0026] A method for heat-setting a valve stent, comprising the aforementioned heat-setting mold for the valve stent, and further comprising: S1. The nickel-titanium alloy valve stent, after laser cutting and preliminary polishing and cleaning, is installed onto the first pre-expanded mold 110. The key nodes at both ends and the middle of the valve stent are fixed by the positioning components 500. Figure 14 As shown, to ensure that it will not shift or twist during subsequent processing, it is then heated. The first pre-expansion mold 110 with the fixed valve stent is transferred as a whole to a heat treatment furnace, and then the furnace temperature is raised to 480°C±10°C at a heating rate of 10°C / min, and held at this temperature for a first preset time of 15 minutes. This process aims to initiate the phase transformation of the nickel-titanium alloy, and to perform preliminary shape setting and stress release for the valve stent. After the holding time, the first pre-expansion mold 110 and the valve stent are quickly removed together and immediately immersed in room temperature deionized water for quenching and cooling to fix the microstructure at this stage. Then the valve stent is removed and cooled to room temperature by water cooling, ready for the next process. S2. After the valve stent has cooled to room temperature following the first pre-expansion treatment, it is removed from the first pre-expansion mold 110 and then installed onto the second pre-expansion mold 120. Similarly, the positioning element 500 of the second pre-expansion mold 120 ensures that the valve stent is properly positioned and subjected to uniform force. The valve stent is then placed back into the heat treatment furnace, heated to 500°C ± 10°C, and maintained at that temperature for 15 minutes. After further adjustments to the valve stent's geometry are made, it is subjected to water quenching again.

[0027] S3. After the second pre-expansion treatment, the valve stent is cooled to room temperature, removed from the second pre-expansion mold 120, and installed on the third pre-expansion mold 130. Then, it is heated to 510°C ± 10°C for 10-15 minutes. This process maximizes the elimination of internal stress accumulated during previous processing and ensures a smooth transition of its contour. After treatment, a quenching operation is performed.

[0028] S4. After cooling the valve stent after the third pre-dilation treatment, install it on the fourth pre-dilation mold 140, and then heat it at a temperature of 510°C±10°C for 15 minutes. After that, remove the fourth pre-dilation mold 140 and remove the valve stent to cool to room temperature.

[0029] S5. Install the pre-dilated valve stent into the first shaping mold 210 or the second shaping mold 220. The diameter of the support part 400 of the shaping mold is consistent with the final design shape of the valve stent product. Therefore, after the valve stent is installed, it is placed in a heat treatment furnace together with the shaping mold for the final heat treatment step, with a heating temperature of 510°C ± 10°C and a heat treatment time of 15-20 minutes. This permanently "memorizes" the final functional shape of the product in the nickel-titanium alloy material. After final quenching, a finished valve stent with accurate geometric dimensions, uniform microstructure, and low residual stress is obtained.

[0030] The above embodiments of the present invention focus on describing the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be described in detail here.

[0031] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A thermoforming mold for a valve stent, comprising a pre-expansion assembly (00) and a shaping assembly (200), characterized in that, The pre-expansion assembly (00) and the shaping assembly (200) both have an inlet end (300) and a support portion (400) in the axial direction. The inlet end (300) is configured to be smaller than the diameter of the valve stent to allow it to pass through. The support portion (400) is provided with a positioning element (500) for fixing the valve stent. The pre-expansion assembly (00) includes a first pre-expansion mold (110), a second pre-expansion mold (120), a third pre-expansion mold (130), and a fourth pre-expansion mold (140), and the diameter of the support portion (400) of the first pre-expansion mold (110), the second pre-expansion mold (120), the third pre-expansion mold (130), and the fourth pre-expansion mold (140) increases sequentially.

2. The valve stent heat-setting mold according to claim 1, characterized in that, The support (400) is constructed as a hollow tubular structure.

3. The valve stent thermoforming mold according to claim 1, characterized in that, The support portion (400) has a head (410), a waist portion (420), and a tail portion (430) in the axial direction. The waist portion (420) of the support portion (400) of both the first pre-expanding mold (110) and the second pre-expanding mold (120) is provided with a positioning element (500). The head (410), waist (420) and / or tail (430) of the support portion (400) of the third pre-expanding mold (130) and the fourth pre-expanding mold (140) are provided with positioning elements (500).

4. The valve stent thermoforming mold according to claim 4, characterized in that, The shaping component (200) includes a first shaping mold (210) and a second shaping mold (220), wherein the support portion (400) of the first shaping mold (210) and the second shaping mold (220) has the same diameter and is larger than the diameter of the support portion (400) of the fourth pre-expanding mold (140).

5. The valve stent thermoforming mold according to claim 4, characterized in that, The bottom of the first shaping mold (210) is also provided with a boss (230), which is connected to the support part (400), and the outer surface of the boss (230) is also provided with a positioning element (500).

6. The valve stent thermoforming mold according to claim 6, characterized in that, The tail (430) of the support part (400) of the second shaping mold (220) is provided with a positioning element (500).

7. A method for heat-setting a valve stent, comprising a valve stent heat-setting mold as described in any one of claims 1-7, characterized in that: S1. The unshaped valve stent is installed on the first pre-expansion mold (110), the valve stent is fixed by the positioning part (500), and then heated. S2. After cooling the valve stent after the first pre-expansion treatment, install it on the second pre-expansion mold (120) and then heat it up; S3. After cooling the valve stent after the second pre-expansion treatment, install it on the third pre-expansion mold (130) and then heat it up; S4. After cooling the valve stent after the third pre-expansion treatment, install it on the fourth pre-expansion mold (140) and then heat it up. S5. After cooling the valve stent after the fourth pre-expansion treatment, install it on the first shaping mold (210) or the second shaping mold (220), and then heat it up.

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