Chemical polishing method, chemical polishing device and lumen stent

Abstract

The present invention relates to the technical field of medical instruments and provides a chemical polishing method, a chemical polishing device, and a lumen stent prepared by means of the chemical polishing method. The chemical polishing method of the present application comprises: immersing a workpiece in a polishing solution; and driving, in a set mode, the polishing solution to flow relative to the workpiece such that the flow velocity of the polishing solution relative to the workpiece is kept basically consistent in the axial direction of the workpiece. The chemical polishing method of the present invention can achieve a uniform and stable polishing effect on the workpiece, the polishing effect is good, and the polishing efficiency is high.

Description

Chemical polishing methods, chemical polishing equipment, and lumen supports Technical Field

[0001] This application relates to the field of medical device technology, specifically to a chemical polishing method, chemical polishing equipment, and a lumen stent prepared by the chemical polishing method, and more specifically to a semi-automatic / automatic chemical polishing method, a semi-automatic / automatic polishing equipment, and a lumen stent prepared by the method. Background Technology

[0002] Lumen stents are implantable medical devices used to treat narrowing or occlusion of blood vessels. Stent implantation reduces elastic recoil and reshapes the vessel, maintaining unobstructed blood flow. Lumen stents are mainly classified according to their implantation site, including coronary stents, cerebral stents, renal artery stents, and peripheral artery stents. Different diameters and sizes of stents are selected based on the diameter and length of the lumen at the lesion site. To achieve their functional role in supporting the blood vessel, luminal stents are designed with different pattern structures. Typically, the overall length of a stent is on the order of millimeters to decimeters, while the thickness of the stent stem is only on the order of tens to hundreds of micrometers. Therefore, luminal stents are medical devices requiring precision manufacturing. Polishing is a critical step in the fabrication process. The uniformity of the stent pattern after polishing directly affects the mechanical properties of the stent when it is supported in the blood vessel and its safety during treatment. Uneven stent patterns may lead to stent breakage during surgery, affecting treatment, or even stent failure. Therefore, ensuring the uniformity of the stent pattern is extremely important.

[0003] Chemical polishing uses a polishing slurry to corrode the workpiece, selectively dissolving and smoothing uneven areas on the surface to ensure the workpiece's dimensions and appearance meet design specifications. Current chemical polishing methods typically involve immersing the workpiece in an agitated polishing slurry using a fixture, often employing a magnetic rotor at the bottom of the container to stir the slurry. However, this method results in inconsistent slurry velocity along the container's height and generates eddies in the circumferential direction. For slender workpieces like tubular supports, ensuring uniform polishing across the entire surface is challenging. This often requires operators to continuously adjust the direction, angle, and duration of the workpiece's immersion in the slurry during polishing. The finished product's pass rate heavily relies on the operator's experience, leading to low polishing efficiency, poor polishing stability, and difficulty in guaranteeing the quality of the supports. Summary of the Invention

[0004] To address the aforementioned technical problems, the present application provides a chemical polishing method and equipment that enables uniform polishing of workpieces with high polishing efficiency.

[0005] As one aspect of this application, a chemical polishing method is provided, comprising: immersing a workpiece in a polishing liquid; driving the polishing liquid to flow relative to the workpiece in a set mode, such that the flow velocity of the polishing liquid relative to the workpiece is substantially consistent along the axial direction of the workpiece.

[0006] According to the chemical polishing method provided by the above technical solution, the step of driving the polishing liquid to flow relative to the workpiece in a set mode specifically includes: driving the workpiece to rotate around a first axis in the polishing liquid at a first rotation speed, wherein the angle between the first axis and the major axis of the workpiece is 0 to 10°; and / or driving the polishing liquid to rotate around a second axis at a second rotation speed, wherein the angle between the second axis and the major axis of the workpiece is 0 to 10°.

[0007] According to the chemical polishing method provided by the above technical solution, the setting mode includes: driving the workpiece to rotate at a uniform or variable speed, wherein the first rotational speed is 0-500 rpm. Further, the first rotational speed is 10-500 rpm; further, the first rotational speed is 40-450 rpm; further, the first rotational speed is 40-350 rpm; further, the first rotational speed is 60-300 rpm. The rotational speed of the workpiece can affect the polishing efficiency, the uniformity of polishing, and also the appearance of the polished workpiece. The higher the rotational speed of the workpiece, the higher the polishing efficiency and the better the uniformity of polishing. However, if the rotational speed is too high, it can also lead to a deterioration in the appearance of the workpiece, such as unevenness or rust, thus reducing the gloss of the workpiece.

[0008] According to the chemical polishing method provided by the above technical solution, the setting mode includes: driving the polishing liquid to rotate at a uniform or variable speed, wherein the second rotation speed is 0-1200 rpm. Further, the second rotation speed is 37.5-1200 rpm; further, the second rotation speed is 37.5-1200 rpm; in some embodiments of the present invention, the second rotation speed affects the polishing efficiency of the workpiece; the higher the second rotation speed, the higher the polishing efficiency of the workpiece. In some embodiments of the present invention, the second rotation speed affects the uniformity of workpiece polishing; the higher the second rotation speed, the better the uniformity of workpiece polishing. In other embodiments, the second rotation speed affects both the polishing efficiency and the uniformity of workpiece polishing. When the second rotation speed affects the polishing efficiency of the workpiece, if the second rotation speed is too high, the polishing efficiency of the workpiece will be too high, leading to some differences between the actual dimensions of the polished workpiece and the corresponding target dimensions.

[0009] According to the chemical polishing method provided by the above technical solution, driving the workpiece to rotate at a variable speed includes: driving the workpiece to rotate in an alternating manner of rotating and stopping, and / or driving the workpiece to rotate alternately in the forward and reverse directions; driving the polishing liquid to rotate at a variable speed includes: driving the polishing liquid to rotate alternately in the forward and reverse directions and / or driving the polishing liquid to rotate at a speed that varies in magnitude.

[0010] According to the chemical polishing method provided by the above technical solution, driving the workpiece to rotate at a variable speed includes: driving the workpiece to rotate alternately for 0.1 seconds to 3 minutes and stopping for 0.1 seconds to 5 seconds, and / or driving the workpiece to rotate alternately in the forward and reverse directions; driving the polishing liquid to rotate at a variable speed includes: driving the polishing liquid to rotate alternately in the forward and reverse directions and / or driving the polishing liquid to rotate at a speed that varies in magnitude.

[0011] According to the chemical polishing method provided by the above technical solution, when the workpiece rotates alternately between rotation and stop, the rotation time is 0.5-75 times the stop time; when the workpiece rotates alternately in the forward and reverse directions, the forward rotation time is 0.5-15.5 times the reverse rotation time. Further, when the workpiece rotates alternately between rotation and stop, the rotation time is 1-75 times the stop time; when the workpiece rotates alternately in the forward and reverse directions, the forward rotation time is 1-15.5 times the reverse rotation time. Further, when the workpiece rotates alternately between rotation and stop, the rotation time is 1-35 times the stop time; when the workpiece rotates alternately in the forward and reverse directions, the forward rotation time is 1-12 times the reverse rotation time. Further, when the workpiece rotates alternately between rotation and stop, the rotation time is 1-25 times the stop time; when the workpiece rotates alternately in the forward and reverse directions, the forward rotation time is 1-10 times the reverse rotation time.

[0012] According to the chemical polishing method provided by the above technical solution, the workpiece is immersed in the polishing liquid in a horizontal direction; and / or the first axis is located in a horizontal direction; and / or the second axis is located in a horizontal direction. Horizontal polishing can eliminate the slight differences in the flow rate of the polishing liquid to different parts of the workpiece 10 along the axial direction caused by gravity, further improving the polishing uniformity along the length of the workpiece; at the same time, it can avoid the long retention time of bubbles and other particles generated during vertical polishing on the surface of the workpiece or moving upward along the surface of the workpiece due to buoyancy, thus affecting the interaction between the polishing liquid and the workpiece surface and affecting the polishing effect. This is especially true when the workpiece has small internal cavities, where the impact on the inner surface is particularly significant. Therefore, by adopting horizontal polishing, the polishing uniformity of the inner surface of the workpiece and along the length of the workpiece can be improved.

[0013] According to the chemical polishing method provided by the above technical solution, the second axis is located outside the area enclosed by the rotation trajectory of the workpiece; and / or the distance from the first axis to the surface of the polishing liquid is less than the distance from the second axis to the surface of the polishing liquid.

[0014] According to the chemical polishing method provided by the above technical solution, the number of workpieces can be one or more. That is, a single polishing can polish one workpiece or polish multiple workpieces at the same time. When polishing multiple workpieces at the same time, the polishing efficiency can be greatly improved.

[0015] According to the chemical polishing method provided by the above technical solution, the number of workpieces is multiple, and the multiple workpieces have the same movement trajectory in the polishing liquid and / or the multiple workpieces are at the same distance from the first axis or the second axis.

[0016] According to the chemical polishing method provided by the above technical solution, the step of driving the workpiece to rotate around a first axis in the polishing liquid at a first rotation speed specifically includes: driving the workpiece to revolve / rotate around the first axis in the polishing liquid at the first rotation speed; and / or the step of driving the polishing liquid to rotate at a second rotation speed specifically includes: stirring the polishing liquid by rotating / revolving around the second axis at a second rotation speed to drive the polishing liquid to rotate.

[0017] According to the chemical polishing method provided by the above technical solution, immersing the workpiece in the polishing liquid specifically includes: limiting the workpiece in the polishing liquid by using a workpiece clamp, and keeping the relative positions of the two ends of the workpiece in the polishing liquid unchanged.

[0018] According to the chemical polishing method provided by the above technical solution, the axial direction of the workpiece is the long axis direction of the workpiece, the length of the workpiece is 8 to 500 mm, and the aspect ratio of the workpiece is 3 to 300.

[0019] According to the chemical polishing method provided by the above technical solution, the distance L between the first axis and the second axis, the first rotational speed r1, and the total rotation time t of the workpiece are negatively correlated, with a correlation coefficient of [-1, 0); and / or the second rotational speed r2 is not positively correlated with the total rotation time t of the workpiece, with a correlation coefficient of [-1, 0]. Where L, r1, and r2 are all average values.

[0020] According to the chemical polishing method provided by the above technical solution, during the polishing process, there is essentially no bubble accumulation on any part of the inner wall and / or outer wall of the support, or the time difference between the residence of bubbles on different parts of the workpiece surface is within 10 seconds. Bubble accumulation affects the uniformity of the polishing fluid's effect on different parts of the workpiece. Significantly reducing the time difference of bubble residence on different parts of the workpiece or completely eliminating bubble accumulation can greatly improve the uniformity of the polishing fluid's effect on the workpiece. Furthermore, the time difference between the residence of bubbles on different parts of the workpiece surface is within 5 seconds; further, the time difference is within 2.5 seconds; further, the time difference is within 1.5 seconds; further, the time difference is within 1 second; and further, the time difference is within 0.5 seconds.

[0021] In this application, if the time for a bubble to accumulate at a certain part of the workpiece surface is less than 2 seconds, it can be considered that there is basically no bubble accumulation.

[0022] According to the chemical polishing method provided by the above technical solution, the workpiece contacts the polishing liquid in a non-fixed area, and the contact area between the workpiece and the polishing liquid during the workpiece's rotation relative to the polishing liquid is not less than 80% of the total surface area of ​​the workpiece. In this invention, the specific area of ​​contact between the workpiece and the polishing liquid varies during the workpiece's rotation relative to the polishing liquid. This variation aims to make the contact time between different areas of the workpiece and the polishing liquid as uniform and consistent as possible, thereby improving the uniformity of workpiece polishing. In some embodiments, the contact area between the workpiece and the polishing liquid during the workpiece's rotation relative to the polishing liquid is not less than 80% of the total surface area of ​​the workpiece; in some embodiments, the contact area is not less than 90% of the total surface area of ​​the workpiece; in other embodiments, the contact area is not less than 95% of the total surface area of ​​the workpiece. The smaller the contact area between the workpiece and the polishing liquid during the rotation of the workpiece relative to the polishing liquid, the more uniform and consistent the interaction / contact time between the workpiece and the polishing liquid in each area is, which is more conducive to improving the uniformity of workpiece polishing.

[0023] As another aspect of this application, a chemical polishing apparatus is provided, comprising a container and a drive device; the container is used to hold a polishing slurry; the drive device is used to drive the polishing slurry to flow relative to a workpiece in a set mode, such that the flow velocity of the polishing slurry relative to the workpiece is substantially consistent along the axial direction of the workpiece.

[0024] According to the chemical polishing equipment provided by the above technical solution, the equipment further includes a workpiece clamp, which includes a polishing fixing device. The polishing fixing device includes a polishing rod or a magnetic fixing device. When the polishing fixing device is a polishing rod, the workpiece is sleeved on the polishing rod along its long axis. When the polishing fixing device is a magnetic fixing device, the workpiece is suspended at the fixed end of the magnetic fixing device. The polishing rod can be a metal rod or a fiber filament.

[0025] According to the chemical polishing equipment provided by the above technical solution, the maximum contact area between the workpiece and the polishing rod is 0.01 to 0.5 times the surface area of ​​the workpiece; the diameter of the polishing rod is smaller than the diameter of the workpiece; the diameter of the polishing rod is 0.3 mm to 18 mm; and the length of the polishing rod is greater than the length of the workpiece.

[0026] According to the chemical polishing equipment provided by the above technical solution, each end of the polishing rod is provided with a limiting member, and the ratio of the length of the polishing rod to the length of the workpiece between the limiting members at both ends is 1.05-1.5. By setting the relative lengths of the polishing rod and the workpiece, sufficient contact between the support and the polishing liquid can be ensured during the polishing process, thereby improving the uniformity of polishing. Furthermore, each end of the polishing rod is provided with a limiting member, and the ratio of the length of the polishing rod to the length of the workpiece between the limiting members at both ends is 1.05-1.2.

[0027] According to the chemical polishing equipment provided by the above technical solution, the ratio of the outer diameter of the polishing rod to the inner diameter of the workpiece is (0, 0.92). The diameter of the polishing rod directly affects the uniformity of workpiece polishing. An excessively large ratio of the outer diameter of the polishing rod to the inner diameter of the workpiece will not only affect the uniformity of workpiece polishing but also the appearance of the workpiece. When the ratio is too large, the contact area between the workpiece and the polishing rod is large during the flow of the polishing liquid relative to the workpiece, meaning the contact / action area between the workpiece and the polishing liquid is relatively small, which is detrimental to the uniformity of workpiece polishing.

[0028] According to the chemical polishing equipment provided by the above technical solution, the distances between each point on the polishing rod and the corresponding positions on the workpiece are substantially equal. The relative magnitude of these distances directly affects the consistency of the contact time between the polishing rod and the support during the flow of the polishing liquid relative to the workpiece, thus affecting the uniformity of workpiece polishing. The phrase "the distances between each point on the polishing rod and the corresponding positions on the workpiece are substantially equal" means that the difference between the maximum and minimum distances between the polishing rod and the corresponding positions on the workpiece is less than 15% of the maximum distance value.

[0029] According to the chemical polishing equipment provided by the above technical solution, the enclosing curve of the polishing rod along the axial direction of the support and the circumferential direction perpendicular to the axial direction of the support is parallel to the enclosing curve of the corresponding position of the inner surface of the workpiece. That is, the more similar the shape formed by the outer surface of the polishing rod is to the shape formed by the inner surface of the workpiece, the more beneficial it is to improve the uniformity of workpiece polishing.

[0030] According to the chemical polishing equipment provided by the above technical solution, the driving device causes the contact area between the workpiece and the polishing rod to vary within the range of 0 to the maximum contact area.

[0031] According to the chemical polishing equipment provided by the above technical solution, the driving device includes a first driving device, which is used to install the workpiece fixture and drive the workpiece to rotate so as to drive the polishing liquid to flow relative to the workpiece.

[0032] According to the chemical polishing equipment provided by the above technical solution, the first driving device includes a clamping shaft, the polishing rod is arranged in parallel and spaced apart from the clamping shaft, and the workpiece rotates around the clamping shaft.

[0033] According to the chemical polishing equipment provided by the above technical solution, the first driving device further includes a first mounting component and a second mounting component. The first mounting component and the second mounting component are fixedly connected to the clamp rotating shaft and are arranged opposite to each other at intervals along the clamp rotating shaft. The two ends of the polishing rod are respectively fixed on the first mounting component and the second mounting component.

[0034] According to the chemical polishing setup provided by the above technical solution, the workpiece fixture includes one polishing rod or multiple polishing rods arranged in parallel. When the rod fixture includes multiple polishing rods arranged in parallel, the multiple polishing rods are arranged parallel to the fixture shaft at equal or unequal distances, and each polishing rod is used to mount at least one workpiece.

[0035] According to the chemical polishing equipment provided by the above technical solution, the driving device includes a second driving device, the second driving device includes a stirring element, and the stirring shaft of the stirring element and the long axis of the workpiece are at an angle of 0 to 10°.

[0036] According to the chemical polishing equipment provided by the above technical solution, the stirring component further includes at least one fan blade, and the fan blade has one or any combination of the following characteristics: each fan blade is connected to the stirring shaft and extends along the length direction of the stirring shaft; the width of the fan blade is substantially consistent along the axial direction of the stirring shaft.

[0037] According to the chemical polishing equipment provided by the above technical solution, the ratio of the length of the stirring element to the length of the workpiece is greater than or equal to 0.8. Further, the ratio of the length of the stirring element to the length of the workpiece is greater than or equal to 0.85. Having a stirring element length of 0.8 or 0.85 times or more of the workpiece length helps ensure the uniformity of the relative flow rate of the polishing liquid on the workpiece surface, thereby improving the uniformity of workpiece polishing.

[0038] According to the chemical polishing equipment provided by the above technical solution, the distance between the outer edge of the fan blade and the corresponding position of the workpiece tends to be equal in the axial direction of the workpiece.

[0039] In this invention, "basically consistent," "basically the same," and "tending to be equal" mean that the difference between the corresponding maximum and minimum values ​​is less than 18% of the maximum value; further, the difference between the corresponding maximum and minimum values ​​is less than 15% of the maximum value; and even further, the difference between the corresponding maximum and minimum values ​​is less than 12% of the maximum value. For example, in this invention, "the flow rate of the polishing fluid relative to the workpiece is basically consistent along the axial direction of the workpiece" means that the difference between the maximum and minimum values ​​of the relative flow rate of the polishing fluid along the axial direction of the workpiece is less than 18% of the maximum value, that is, the minimum value of the relative flow rate of the polishing fluid along the axial direction of the workpiece is not less than 82% of the maximum value; similarly, in this invention, "the interval between the outer edge of the fan blade and the corresponding position of the workpiece tends to be equal along the axial direction of the workpiece" means that the minimum interval between the outer edge of the fan blade and the corresponding position of the workpiece is not less than 82% of the maximum interval; further, the minimum interval between the outer edge of the fan blade and the corresponding position of the workpiece is not less than 85% of the maximum interval; and the minimum interval between the outer edge of the fan blade and the corresponding position of the workpiece is not less than 88% of the maximum interval.

[0040] In this invention, the phrase "the distance between the outer edge of the fan blade and the corresponding position of the workpiece tends to be equal along the axial direction of the workpiece" refers to the distance between two intersection points of the curve formed by a straight line parallel to the x-axis or y-axis, the outer edge of the fan blade, and the outer wall of the workpiece. Other similar expressions can be found here.

[0041] The phrase "keeping the relative positions of the two ends of the workpiece in the polishing liquid unchanged" as used in this invention means that the two ends of the workpiece in the axial direction will not shift significantly relative to the center of the workpiece.

[0042] According to the chemical polishing equipment provided by the above technical solution, the distance between the outer edge of the fan blade and the corresponding position of the workpiece is 0.1 to 150 mm. The size of this distance affects both the uniformity and efficiency of the polishing process; a smaller distance results in higher efficiency, but too small a distance will affect the uniformity of the polishing and the appearance of the polished workpiece. In some embodiments of the present invention, the distance between the outer edge of the fan blade and the corresponding position of the workpiece is 0.1 to 150 mm; further, in some embodiments of the present invention, the distance is 0.1 to 100 mm; further, in some embodiments of the present invention, the distance is 0.1 to 80 mm; and even further, in some embodiments of the present invention, the distance is 0.5 to 80 mm.

[0043] The polishing method and equipment provided by this invention are suitable for polishing some relatively fine workpieces; furthermore, they are suitable for polishing some high-precision workpieces; furthermore, they are suitable for polishing medical devices; furthermore, they are suitable for polishing biodegradable medical devices; furthermore, they are suitable for chemical polishing with highly corrosive chemical polishing solutions (pH of the polishing solution is 3 or below, even 2 or below). The stronger the corrosiveness of the chemical polishing solution, the stronger the polishing / corrosion effect on the workpiece per unit time, thus requiring higher operational standards. Even a slight operational error can affect both the stability and uniformity of the polishing. For example, if a certain part of the workpiece is exposed to the polishing solution for slightly less time than other parts, it will have a significant adverse effect on the uniformity of the workpiece polishing; furthermore, the polishing method and equipment provided by this invention are particularly suitable for polishing biodegradable tubular stents.

[0044] The biodegradable materials include, but are not limited to, biodegradable iron-based, zinc-based, magnesium-based, and aluminum-based materials.

[0045] As another aspect of this application, a lumen stent prepared by chemical polishing is provided, wherein: the lumen stent is a tubular body with a hollowed-out pattern, and the cross-sectional profile of the lumen stent is a closed smooth curve; the wall thickness removal of the lumen stent before and after polishing is 5% to 95%.

[0046] According to the lumen support provided by the above technical solution, the chemical polishing method is the chemical polishing method described in any one of claims 1 to 11.

[0047] According to the luminal stent provided by the above technical solution, the vascular stent is a biodegradable luminal stent; further, the luminal stent includes an iron-based stent, a zinc-based stent, or a magnesium-based stent; further, the material of the luminal stent includes pure iron, iron alloy, pure zinc, zinc alloy, pure magnesium, and magnesium alloy; further, the substrate of the vascular stent includes pure iron and iron alloy; further, the substrate of the vascular stent includes pure iron and biodegradable iron alloy.

[0048] According to the luminal stent provided by the above technical solution, the length of the vascular stent is 8-500 mm, the aspect ratio of the stent in the expanded state is 2-150, the wall thickness of the stent is 30-500 μm, and the strut width of the stent is 45-650 μm. In some embodiments of the present invention, the wall thickness of the stent is 30-500 μm, and the strut width of the stent is 45-650 μm; in some embodiments of the present invention, the wall thickness of the stent is 30-450 μm, and the strut width of the stent is 45-550 μm; in some embodiments of the present invention, the wall thickness of the stent is 30-400 μm, and the strut width of the stent is 45-450 μm.

[0049] According to the luminal stent provided by the above technical solution, the wall thickness removal amount after polishing of the vascular stent is [5%, 20%), (20%, 60%) or (60%, 95%).

[0050] According to the lumen stent provided by the above technical solution, the standard deviation of each dimension of the stent after polishing is no greater than 15μm; further, the standard deviation of each dimension of the stent after polishing is no greater than 10μm; further, when the rod width / wall thickness of the stent rod is 180μm or more, the standard deviation of each dimension of the stent after polishing is no greater than 10μm; when the rod width / wall thickness of the stent rod is less than 180μm, the standard deviation of each dimension of the stent after polishing is no greater than 8μm; further, the standard deviation of each dimension of the stent after polishing is no greater than 8μm; further, the standard deviation of each dimension of the stent after polishing is no greater than 5μm.

[0051] The phrase "the standard deviation of all dimensions of the bracket after polishing is not greater than a certain value" in this invention includes both the standard deviation of the dimensions of each part of a single bracket not being greater than a certain value, and the standard deviation of the average value of each parameter of multiple brackets not being greater than a certain value. For example, "the standard deviation of all dimensions of the bracket after polishing is not greater than 5μm" includes both the standard deviation of the rod width / wall thickness values ​​of each part of a single bracket after polishing not being greater than 5μm, and the standard deviation of the rod width / wall thickness (average value) of multiple brackets not being greater than 5μm.

[0052] In this invention, "the standard deviation of each dimension of the workpiece / support after polishing" refers to the standard deviation of each dimension of the workpiece / support brought about by the polishing process. That is, it is the degree of dispersion of a certain dimension caused by this process alone. In other words, when a process before polishing introduces a difference in a certain dimension of the workpiece / support, the standard deviation of that dimension after polishing is obtained by subtracting the standard deviation of the workpiece / support caused by the previous process. For example, if the standard deviation of the support wall thickness after polishing is 3 μm, while the standard deviation of the support wall thickness before polishing is 1.8 μm, then the standard deviation of the support wall thickness brought about by the polishing process is 1.2 μm. That is, the standard deviation of the support wall thickness after polishing is 1.2 μm.

[0053] The phrase "the standard deviation of each dimension of the bracket after polishing is not greater than a certain value" as used in this invention includes both the standard deviation of the bracket's width and the standard deviation of its wall thickness after polishing being not greater than a certain value. It can also be understood as the average value of the wall thickness and width of a single bracket after polishing being within the target value (W) ± standard deviation (SD), and the wall thickness and width at different locations of a single bracket after polishing being within the target value (W) ± standard deviation (SD).

[0054] The luminal stents in this invention include all luminal stents used in living organisms, such as vascular stents, renal artery stents, prostate stents, and neural stents.

[0055] The chemical polishing method and equipment provided in this application achieve a relatively consistent polishing effect in both the axial and radial directions of the workpiece by driving a relative flow between the polishing slurry and the workpiece, with the flow velocity of the polishing slurry relative to the workpiece remaining essentially constant. This enables the chemical polishing process for precision workpieces to be transformed from manual to semi-automatic or even fully automated, particularly for precision medical device workpieces such as luminal stents. This significantly reduces manual intervention and reliance on operator experience during the polishing process, while also improving polishing quality, product stability, and polishing efficiency. It is suitable for fine polishing of slender workpieces such as luminal stents, resulting in metal or alloy absorbable luminal stents with a polishing standard deviation of no more than 10 μm, a length of 8–500 mm, an aspect ratio of 2–150, and a wall thickness of 30–500 μm, and a closed, smooth curved cross-section. The method and equipment provided by this invention are particularly suitable for polishing long supports (supports with a length of more than 38mm), and can significantly improve the uniformity and stability of polishing long supports. Attached Figure Description

[0056] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0057] Figure 1 is a partial flowchart of the chemical polishing method provided in the embodiments of this application;

[0058] Figure 2 is a schematic diagram of the structure of a chemical polishing apparatus provided in one embodiment of this application;

[0059] Figure 3 is a schematic diagram of one state of the chemical polishing equipment shown in Figure 2 during the polishing process;

[0060] Figure 4 is a schematic diagram of the structure of a chemical polishing apparatus provided in another embodiment of this application;

[0061] Figure 5 is a cross-sectional enlarged schematic diagram of an exemplary structure of the stirring element in the chemical polishing equipment of this application;

[0062] Figure 6 is a schematic diagram of an exemplary structure of the mounting components in the chemical polishing equipment of this application;

[0063] Figure 7 is a schematic diagram of the structure of a chemical polishing apparatus provided in another embodiment of this application;

[0064] Figure 8 is a schematic diagram of the structure of a chemical polishing apparatus provided in another embodiment of this application;

[0065] Figure 9 is a schematic diagram of the structure of a chemical polishing apparatus provided in another embodiment of this application;

[0066] Figure 10 is a schematic diagram of the structure of a chemical polishing apparatus provided in another embodiment of this application. Test Method

[0067] Luminosity

[0068] The brightness of the entire outer and inner walls of the support structure is fully inspected using a three-dimensional measuring microscope at an appropriate magnification (e.g., 50-200x). The brightness levels are ranked from best to worst as follows: extremely high, relatively high, high, medium, average, and poor. Detailed Implementation

[0069] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings, embodiments, and examples. It should be understood that the specific embodiments and examples described herein are merely illustrative of the invention and are not intended to limit the invention.

[0070] It should be noted that the terms "setup" and "connection" should be interpreted broadly. For example, they can refer to direct setup or connection, or indirect setup or connection through centered components or centered structures.

[0071] Furthermore, in embodiments of this invention, terms such as "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" are used to indicate orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, or in a conventional placement or usage state. These terms are merely for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the structures, features, devices, or elements referred to must have a specific orientation or positional relationship, nor that they must be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more, and the terms "within," "within," "below," and "above" related to numerical values ​​include the numerical value itself.

[0072] The various specific technical features and embodiments described in the detailed embodiments can be combined in any suitable manner without contradiction. For example, different implementation methods can be formed by combining different specific technical features / embodiments. In order to avoid unnecessary repetition, the various possible combinations of the various specific technical features / embodiments in this invention will not be described separately.

[0073] This invention provides a chemical polishing method that uses a polishing slurry to polish a workpiece immersed in it, achieving the desired surface finish. The polishing slurry can be selected from commercially available products or custom-mixed based on the workpiece's characteristics and polishing requirements; details are omitted here. The workpiece to be polished can be any part requiring surface treatment, such as pipes, electrical products, or medical devices. Furthermore, this polishing method is particularly suitable for polishing workpieces with complex shapes and internal polishing requirements. In this embodiment, for ease of understanding, a tubular support is used as the workpiece to be polished, but this does not limit the application scope of this chemical polishing method.

[0074] Please refer to Figure 1, which is a schematic flowchart of a chemical polishing method according to one embodiment of this application. The chemical polishing method includes the following steps:

[0075] S01: Immerse the workpiece in the polishing solution;

[0076] S02: Drive the polishing liquid to flow relative to the workpiece in a set mode, and make the flow velocity of the polishing liquid relative to the workpiece basically consistent in the axial direction of the workpiece.

[0077] To facilitate the explanation of the chemical polishing method according to the embodiments of this application, a detailed description will be provided below with reference to the chemical polishing equipment shown in Figures 2-9. It should be understood that driving the polishing liquid to flow relative to the workpiece means that the polishing liquid is flowing when the workpiece is used as a reference in various setting modes. The chemical polishing method according to the embodiments of this application is not limited to using any of the chemical polishing equipment described in the accompanying drawings and embodiments of this application.

[0078] As a feasible implementation method, the chemical polishing method provided in this invention can be performed using a chemical polishing apparatus 1. The chemical polishing apparatus 1 includes a container 12 for holding a polishing liquid 90. The workpiece 10 is immersed in the polishing liquid and can remain submerged below the liquid surface 900 during the polishing process. A driving device drives the polishing liquid to flow relative to the workpiece 10 in a set mode, ensuring that the flow velocity of the polishing liquid relative to the workpiece 10 remains substantially consistent along the axial direction of the workpiece 10. This application primarily uses the longitudinal axis of the workpiece 10 as an example for explanation. It should be understood that the polishing method of this application is not limited to generating a substantially consistent flow velocity along the longitudinal axis; it can also generate a substantially consistent flow velocity along the minor axis, or a substantially consistent flow velocity along both the longitudinal and minor axes, depending on the type of workpiece 10 and the polishing requirements. By driving the polishing fluid to generate a basically consistent flow rate along the 10-axis of the workpiece, the polishing amount of each part along the 10-axis of the workpiece can be made basically consistent, improving the overall polishing uniformity. At the same time, by driving the polishing fluid to generate a basically consistent flow rate along the 10-axis of the workpiece, air bubbles on the workpiece surface can also be promptly removed / eliminated, avoiding different effects of the polishing fluid on different parts of the workpiece due to the accumulation of air bubbles or the different accumulation times of air bubbles on different parts of the surface, thus avoiding uneven polishing of the workpiece surface.

[0079] When used for polishing lumen stents, this method can reduce the standard deviation of various dimensions of the stent to within 8 μm, and even to within 5 μm. For precision instruments like lumen stents, ensuring the stability of the quality of multiple stents after polishing is relatively easy. For example, it is relatively easy to achieve an RSD of less than 2% or even less than 1% after polishing multiple stents using a certain method. However, ensuring that the various dimensional parameters of the stent are relatively stable, such as having a standard deviation of less than 8 μm or even 5 μm, is quite difficult, especially for some long and hollow workpieces.

[0080] As a feasible implementation method, this method drives the workpiece 10 to rotate around a first axis S1 in the polishing slurry at a first rotational speed. The angle between the first axis S1 and the major axis of the workpiece 10 is set to 0-10°, so that the distance between each part of the workpiece 10 and the first axis S1 in the major axis direction is approximately the same, thus obtaining a consistent output speed. This corresponds to a relatively consistent polishing slurry flow rate at the contact position between the workpiece 10 and the polishing slurry. The selective dissolution effect of the flowing polishing slurry on the uneven areas of the workpiece 10 surface eliminates scratches and erosion, thereby obtaining a consistent polishing amount along the axial direction and improving the overall polishing uniformity. Taking the rotating workpiece 10 as a reference, the polishing slurry around the workpiece is in motion relative to the workpiece 10, that is, the polishing slurry flows relative to the workpiece 10, realizing the circulation and renewal of the polishing slurry on the surface of the workpiece 10, thereby ensuring the reliability and efficiency of the polishing effect.

[0081] As another feasible implementation, this method drives the polishing liquid to rotate around the second axis S2 at a second rotation speed, wherein the angle between the second axis S2 and the long axis of the workpiece 10 is 0 to 10°, so that the distance between the second axis S2, which serves as the power output axis, and each part of the workpiece 10 in the long axis direction is approximately equal, thereby making each part of the workpiece 10 in the long axis direction located in the region where the flow rate generated by the rotation of the polishing liquid is basically consistent, and obtaining a consistent polishing amount to improve polishing uniformity.

[0082] As another feasible implementation, the workpiece 10 is driven to rotate around a first axis S1 in the polishing slurry at a first rotational speed, while the polishing slurry is driven to rotate around a second axis S2 at a second rotational speed. The angles between the first axis, the second axis S2, and the major axis of the workpiece 10 are 0° to 10°. By driving the workpiece 10 to rotate, it moves within the polishing slurry, and simultaneously, the rotation of the polishing slurry drives the slurry to flow towards the workpiece 10. The speeds generated by the active movements of both are superimposed and remain essentially consistent along the major axis of the workpiece 10, further improving polishing efficiency while ensuring polishing uniformity. In addition, by generating a relative flow velocity through rotating the workpiece 10 or the polishing slurry, a relatively uniform polishing effect can be obtained simultaneously in the circumference of the workpiece 10, further improving the overall polishing uniformity of the workpiece 10.

[0083] Furthermore, in this method, the direction driving the workpiece 10 to rotate is opposite to the direction driving the polishing slurry to rotate. For example, the workpiece 10 can rotate clockwise around the first axis S1 and the polishing slurry can be stirred counterclockwise around the second axis S2, or vice versa. The opposite rotation direction can increase the impact speed between the polishing slurry and the workpiece 10, further improving polishing efficiency. Polishing can be achieved using a relatively low-power motor when the polishing slurry has high concentration, high density, and high resistance. Of course, the workpiece 10 and the polishing slurry can also rotate in the same direction. With appropriate axis spacing and rotation speed, better polishing uniformity can be obtained when the first axis S1 coincides with the second axis S2. It should be understood that the first and second rotation speeds are only used to define the rotation speeds that provide the driving force for the workpiece rotation and the rotation speeds that provide the driving force for the polishing slurry rotation, and are not used to limit the numerical relationship between the two.

[0084] Furthermore, the angle between the first axis S1 and the major axis of the workpiece 10 can be 0–9°, 0–8°, 0–5°, 0–4°, 0–3°, 0–2°, 1°–5°, or any value within the above range, such as 0°; the angle between the second axis S2 and the major axis of the workpiece 10 can further be 0–9°, 0–8°, 0–5°, 0–4°, 0–3°, 0–2°, 1°–5°, or any value within the above range, such as 0°. As an example, the angle between the first axis S1, the second axis S2, and the major axis of the workpiece 10 is 0°, and they are parallel to each other.

[0085] In one feasible implementation, the workpiece 10 can be held in place within the polishing liquid by a workpiece clamp such as the polishing rod 1421 in the chemical polishing equipment 1 shown in Figure 2, thereby maintaining its relative position during the polishing process to keep the included angles with each axis within a predetermined range. Specifically, the workpiece 10 is fitted onto the polishing rod 1421 along its long axis, so that the relative positions of the two ends of the workpiece 10 along its long axis remain unchanged in the polishing liquid. Specifically, the workpiece 10 is held in place by the polishing rod 10, so that the two ends of the workpiece along its long axis do not deflect significantly relative to the workpiece center, and the depth difference between the two ends of the workpiece 10 along its axial direction in the polishing liquid remains essentially unchanged. This ensures that each part of the workpiece along its long axis is stably located in the polishing liquid with a uniform flow rate, and also prevents the workpiece 10 from falling to the bottom of the container, or coming into contact with other devices in the polishing container, such as agitators, or causing disordered movement in the flowing polishing liquid, which would result in uncontrollable polishing quality.

[0086] As one possible implementation, the driving device may include a second driving device 13 and a first driving device 14, as shown in FIG. 2. The first driving device 14 is used to mount the workpiece fixture and drive the workpiece fixture and the workpiece 10 limited by the workpiece fixture to rotate around the first axis S1, thereby driving the polishing liquid to flow relative to the workpiece by rotating the workpiece 10 in the polishing liquid 90. The second driving device 13 is used to rotate and stir the polishing liquid 90, so that the polishing liquid flows to the workpiece 10. Specifically, it may include a stirring element 131 in the polishing liquid and a stirring drive unit 132 for driving the stirring element 131. In this example, the axis of the stirring element 131 is the second axis S2, and the stirring element 131 rotates around the second axis S2. The workpiece mounting axis S3 coincides with the axis of the polishing rod 1421. After the workpiece 10 is mounted on the polishing rod 1421, its major axis coincides with the workpiece mounting axis S3. Therefore, by setting the angle between the workpiece mounting axis S3 and the first axis S1 and the second axis S2 to -10° to 10°, the angle between the major axis of the workpiece 10 and the first axis S1 and the second axis S2 can be maintained between 0° and 10°. In the example of Figure 2, the first axis S1 is parallel to the workpiece mounting axis S3, and there is a certain distance between the two axes. That is, the workpiece 10 revolves around the first axis S1. The greater the distance between the workpiece 10 and the first axis S1, the greater the flow velocity of the polishing liquid relative to the workpiece 10 under the same driving force. It should be understood that the driving device may also include only one of the second driving device 13 and the first driving device 14, which are used to drive the workpiece 10 to rotate around the first axis S1 in the polishing liquid, or to drive the polishing liquid to rotate around the second axis S2.

[0087] Of course, in other embodiments, the first axis referred to in the chemical polishing method of this application is not limited to the specific examples described above. For example, the workpiece 10 can also rotate around the workpiece mounting axis S3 as the polishing rod 1421 rotates. In this case, the workpiece mounting axis S3 is equivalent to the first axis S1, that is, the axis of rotation of the workpiece 10. In addition to rotating around its own axis, the stirring member 131 can also revolve around an axis other than itself, such as rotating around the workpiece mounting axis S3. This is equivalent to the stirring member 131 making a circular motion around the workpiece 10. In this case, the workpiece mounting axis S3 is equivalent to the second axis S2, that is, the axis of rotation or stirring of the polishing liquid. Alternatively, the stirring member 131 can rotate around the second axis S2 and simultaneously make a circular motion around the workpiece 10. That is, in addition to rotating itself, the stirring member 131 can also make a circular motion around the workpiece 10 with the position of the workpiece 10 as the center of rotation. Alternatively, the workpiece 10 can rotate around the workpiece mounting axis S3 and simultaneously perform circular motion around the stirring element 131. That is, both the stirring element 131 and the workpiece 10 can rotate, and the workpiece 10 can also perform circular motion around the stirring element 131 with the position of the stirring element 131 as the center of rotation. Alternatively, the workpiece 10 can rotate around the workpiece mounting axis S3 and simultaneously perform circular rotation around the first axis S2. The chemical polishing method of this application provides a variety of motion modes for driving the polishing liquid to generate different flow rates relative to the workpiece 10, making the method have a wide range of applications. When there are multiple workpieces 10, and each rotates only with its corresponding polishing rod, the first axis is located in the middle position of the polishing rod, thus ensuring that the distance between the multiple workpieces and the first axis is the same.

[0088] In some feasible embodiments, the workpiece 10 is immersed in the polishing liquid in a horizontal direction. Specifically, this can be achieved by fixing the polishing rod 1421 horizontally to the first drive device 14, with the workpiece mounting axis S3 located in a horizontal direction and the workpiece 10 correspondingly located in a horizontal direction. For some workpieces, especially slender ones, horizontal polishing can eliminate slight differences in the flow rate of polishing fluid along the 10-axis of the workpiece caused by gravity, further improving the polishing uniformity along the workpiece's length. Simultaneously, it avoids the problem of air bubbles, generated during vertical polishing, adhering to the surface of some parts of the workpiece or remaining on certain surfaces for extended periods due to buoyancy. This can lead to inconsistent interaction between different parts of the workpiece surface and the polishing fluid, affecting the polishing effect. Especially when the workpiece has small internal cavities, air bubbles tend to accumulate on the inner surface of the support, making them difficult to disperse or remaining on the entire inner surface or a portion thereof for a longer time. This results in some surfaces having high polishing removal and others low removal, leading to uneven polishing. This unevenness worsens with increasing support length. Therefore, horizontal polishing effectively avoids the inconsistent retention time of air bubbles on different parts of the workpiece surface, significantly improving the polishing uniformity of the inner surface and along the workpiece's length. After polishing, the standard deviation of various workpiece dimensions can reach no more than 10 μm, and even no more than 5 μm. Even for small or slender workpieces with delicate and complex structures, the standard deviation of each dimension after polishing can reach no more than 5 μm or even smaller. The polishing method and equipment of this application are particularly suitable for polishing slender supports longer than 38 mm. For such slender and hollow supports, ensuring the uniformity and stability of polishing is particularly difficult. However, using the method or equipment provided in this application, the standard deviation of polishing can reach no more than 5 μm or even smaller, exhibiting excellent polishing uniformity and stability. Moreover, the uniformity and stability of polishing hardly change with the length of the support.

[0089] In other feasible embodiments, when using chemical polishing equipment 3 as shown in Figure 7 and polishing equipment 4 as shown in Figure 8, the workpiece 10 is placed vertically (perpendicular to the horizontal direction), and the corresponding workpiece rotation axis or polishing liquid rotation axis is also placed vertically or maintains an angle of 0 to 10° with the axis of the workpiece 10. Of course, the workpiece 10 can also be at any angle with the horizontal line, and the workpiece rotation axis or polishing liquid rotation axis can maintain an angle of 0 to 10° with the axis of the workpiece 10, all of which can achieve the effect of uniform polishing of the workpiece 10 by the polishing liquid. Horizontal polishing and vertical polishing are beneficial to the installation of various components of the driving device, such as the agitator 131. Preferably, the distance from the first axis S1 to the liquid surface 900 of the polishing liquid is less than the distance from the second axis S2 to the liquid surface 900. For example, the agitator 131 can be located below the workpiece 10. Thus, the agitator 131 can drive the polishing liquid to flow vertically upward. Under the action of gravity, the polishing liquid will not deflect in the horizontal direction, and the flow direction of the polishing liquid when it flows to the workpiece 10 is vertical, which makes it easier to predict the polishing effect of the workpiece 10. Meanwhile, this arrangement also facilitates the disassembly and assembly of the workpiece 10, making it convenient to disassemble the workpiece 10 after polishing and to install the workpiece 10 to be polished. Of course, the first axis S1 can also be located at the same level as the second axis S2 to accommodate situations where the height of the container 12 is limited, making the chemical polishing method of this application applicable to more polishing scenarios and needs. Preferably, the second axis S2 is located outside the area enclosed by the rotation trajectory of the workpiece 10. Referring to Figure 4, the workpiece rotates along the first axis S1 in the horizontal direction, and the area Z1 enclosed by the upper boundary B1 and the lower boundary B2 of the movement trajectory, and the second axis S2 around which the polishing liquid is stirred is located outside the area Z1. The clamping shaft 241 included in the first driving device 24 uses its own axis as the workpiece rotation axis, i.e., the first axis S1, and the stirring component 231 included in the second driving device 24 uses its own axis as the axis of stirring the polishing liquid, i.e., the second axis S2. This facilitates the installation of the clamping shaft 241 and the stirring component, and also facilitates the picking and placing of the workpiece 10.

[0090] In some embodiments, the second drive device 13 can drive the polishing slurry to flow along the direction of rotation of the vertical stirring member 131. In this way, when the polishing slurry flows to the workpiece 10, the flow direction of the polishing slurry is approximately perpendicular to the axis of the workpiece 10, that is, the polishing slurry polishes the workpiece 10 approximately perpendicular to the wall thickness of the workpiece 10, thereby achieving a better polishing effect.

[0091] In some feasible embodiments, the setting mode adopted by the chemical polishing method of this application includes driving the workpiece 10 to rotate at a uniform or variable speed in the polishing liquid, or driving the polishing liquid to rotate at a uniform or variable speed, or driving the workpiece 10 to rotate at a uniform or variable speed in the polishing liquid and simultaneously driving the polishing liquid to rotate at a uniform or variable speed. Specifically, variable speed motion includes changing the direction of motion and / or changing the magnitude of the rotation speed. Changing the direction of motion can be alternating between forward and reverse rotation, such as alternating between counterclockwise and clockwise rotation. Conversely, uniform speed rotation means that the direction of motion and the magnitude of the speed remain unchanged. Because workpiece 10 is generally a three-dimensional structure, and due to the complexity of liquid flow, when the polishing slurry flows on the surface of workpiece 10, there will be slight differences between the portion facing the direction of the polishing slurry flow velocity and the portion facing away from the flow velocity direction. By rotating the workpiece or the polishing slurry at varying speeds, the flow direction and / or velocity of the polishing slurry relative to workpiece 10 can be changed. This eliminates the flow differences of the polishing slurry in different parts of the workpiece 10 surface over time, further improving the polishing uniformity of workpiece 10, and allowing the workpiece polishing standard deviation to be within 5 μm or even smaller. It should be understood that the definitions of positive and negative can also be reversed.

[0092] Furthermore, as an example, when the workpiece 10 is driven to rotate at a constant or variable speed in the polishing slurry, the rotational speed of the workpiece 10, i.e., the first rotational speed, is 0 to 450 rpm; when the polishing slurry is driven at a constant or variable speed, the second rotational speed, for example, is the rotational speed of the stirring element 131, which is 0 to 1200 rpm. Within the above rotational speed range, the flow of the polishing slurry relative to the workpiece allows the polishing slurry to create a certain scouring effect on the surface of the workpiece 10, causing the protruding parts on the surface of the workpiece 10 to be dissolved more quickly and achieving more uniform polishing, which can keep the standard deviation of the workpiece polishing within 5 μm.

[0093] Furthermore, the rotational speed of the workpiece 10 can be preferably set to 0–500 rpm, 40–450 rpm, 60–350 rpm, or 60–3000 rpm; the rotational speed of the agitator 131 can be 0–1200 rpm, 50–1200 rpm, 37.5–1000 rpm, 100–1200 rpm, 200–1200 rpm, 300–1200 rpm, or 400–1200 rpm, etc. This ensures good flow of the polishing fluid around the workpiece 10, resulting in a better polishing effect. The polishing standard deviation can be further controlled within 4 μm or even smaller, such as within 3 μm or 2 μm. Simultaneously, it avoids the workpiece 10 from experiencing excessive longitudinal corrosion in the wall thickness direction due to being in a relatively slow-flowing polishing fluid, thus preventing changes in the overall structural characteristics of the workpiece. This allows the workpiece 10 to achieve a good overall mirror finish while satisfying uniform polishing requirements.

[0094] In some embodiments, the workpiece 10 can change its rotation speed by alternating between rotation and stop. During the rotation of the workpiece 10, due to the centripetal force, a portion of the workpiece 10 will be in close contact with the polishing rod 1421. The polishing fluid flow rate is relatively low at this location due to obstruction, resulting in uneven polishing of the workpiece 10. When the workpiece 10 rotates in variable speed mode, due to the difference in inertia between the polishing fluid and the workpiece 10, the polishing fluid will push the workpiece 10 to undergo a momentary rotation relative to the workpiece mounting axis (equivalent to workpiece rotation), thereby changing the contact position with the polishing rod 1421. This results in more uniform circumferential polishing of the workpiece 10, further reducing the polishing standard deviation to 5 μm or even lower. In other embodiments, changing the rotation speed can also include continuously changing the rotation speed, for example, driving the workpiece from 30 rpm to 150 rpm, and then gradually decreasing it back to 30 rpm. Of course, you can also change speeds in other ranges, such as increasing from 60 rpm to 150 rpm, and then gradually decreasing from 150 rpm to 60 rpm.

[0095] In some feasible solutions, the workpiece 10 can rotate clockwise or counterclockwise. Counterclockwise rotation can be defined as positive, and clockwise rotation as negative. The workpiece 10 can be driven to rotate alternately in both directions, or the polishing slurry can be driven to rotate alternately in both directions. Rotating the polishing slurry in opposite directions allows it to wash the opposite sides of the workpiece 10 along its axial direction, resulting in more uniform polishing on both sides. The workpiece 10 can rotate at least one revolution in one direction before rotating in the opposite direction. This results in a more consistent flow rate of the polishing slurry around the workpiece 10, leading to better polishing. Furthermore, when the diameter of the polishing rod 1421 is smaller than the diameter of the workpiece 10, alternating clockwise and counterclockwise rotation of the workpiece 10 increases the time the workpiece 10 is out of contact with the polishing rod 1421, reducing uneven polishing caused by obstruction at the contact points between the polishing rod 1421 and the workpiece 10, such as the inner wall of the workpiece 10. Driving the polishing slurry to rotate alternately in both directions has a similar effect. In other examples, the variable speed rotation of workpiece 10 can also be a combination of direction change and speed change.

[0096] In some implementations, in the variable-speed rotation mode of workpiece 10, the time for driving workpiece 10 to rotate is 0.1 seconds to 3 minutes, and the time for stopping driving workpiece 10 is 0.1 seconds to 5 seconds. At the same initial rotation speed, the shorter the stop time, the faster the polishing speed. The relative size of the stop time can be set according to the polishing volume requirements. When the time for driving workpiece 10 to rotate is less than 0.1 seconds, because the time is too short, workpiece 10 stops rotating as soon as it starts to rotate, making it difficult for the polishing fluid to effectively drive workpiece 10 to rotate and generate a high flow rate to quickly flush the protruding parts of the workpiece 10 surface. When the time for driving workpiece 10 to rotate is greater than 3 minutes, the frequency of interruptions of workpiece 10 during the entire polishing process is relatively low, and the circumferential polishing of workpiece 10 may still not be uniform enough. When the time for stopping the drive of workpiece 10 is less than 0.1 seconds, the rotational speed of workpiece 10 has not decreased significantly, the centripetal force on workpiece 10 is still relatively large, and the polishing fluid is unable to drive workpiece 10 to rotate instantaneously. When the time for stopping the drive of workpiece 10 is greater than 5 seconds, workpiece 10 remains stationary for a relatively long time, and the circumferential polishing of workpiece 10 is not uniform enough. Furthermore, the time for driving workpiece 10 to rotate can include, but is not limited to, 0.1 seconds to 2.5 minutes, 0.5 minutes to 3 minutes, 10 seconds to 1 minute, 20 seconds to 3 minutes, or 1 minute to 2 minutes. The time for stopping the drive of workpiece 10 can include, but is not limited to, 0.1 to 2 seconds, 0.5 to 4 seconds, 0.2 to 3 seconds, 0.5 to 1 second, or 0.2 to 1.5 seconds.

[0097] Furthermore, the drive to drive the workpiece 10 can be stopped after each rotation through a different angle. Alternatively, the rotation time of the workpiece 10 can be adjusted so that the angle rotated by the workpiece 10 is different each time it stops rotating. Thus, the position of the workpiece 10 in contact with the polishing rod 1421 is different each time it restarts rotation, thereby improving the uniformity of the polishing fluid contact at different positions of the workpiece 10, and consequently improving the uniformity of circumferential polishing of the workpiece 10. Of course, the drive to drive the workpiece 10 can also be stopped after each rotation through the same angle; or the rotation time of the workpiece 10 can be adjusted so that the angle rotated by the workpiece 10 is the same each time it stops rotating.

[0098] In some feasible implementations, there are multiple workpieces 10, and the multiple workpieces move along the same trajectory in the polishing fluid. Referring to Figure 4, two different polishing rods 2421 are used to limit the movement of two workpieces 10. Both workpieces 10 are spaced at the same distance from the first axis S1 (which coincides with the central axis of the fixture shaft 241). When the workpieces 10 rotate around the first axis S1, the movement trajectories of the two workpieces 10 are circles of the same size. Under the condition of consistent driving force, such as sharing the same fixture shaft 241 as the shaft, each workpiece 10 has a relatively consistent polishing fluid flow rate in its axial direction. In this way, multiple workpieces can be polished simultaneously, which can greatly improve the overall efficiency and ensure that each workpiece polished at the same time has good polishing uniformity, and make the polishing effect between batches of workpieces of the same specification have high consistency.

[0099] In some feasible implementations, multiple workpieces 10 are equidistant from the first axis S1. Taking Figure 4 as an example, each workpiece 10 is equidistant from the first axis S1. When the workpieces rotate around the first axis S1, each workpiece 10 can have a relatively consistent polishing fluid flow rate in its axial direction. Furthermore, the shortest distance between each workpiece 10 and the second axis S2 is equal. For example, the stirring element 232 is positioned below the fixture shaft 241, so that the polishing fluid flow rate caused by the rotation of the stirring element 232 around the second axis S2 is consistent across the axial direction of each workpiece 10, resulting in a relatively consistent polishing effect for multiple workpieces 10 in the same batch.

[0100] In this chemical polishing method, the length of the workpiece 10 is 8–500 mm, the length-to-width ratio is 3–300, and the width of the workpiece 10 is relatively narrow. While the polishing slurry flows along the entire length of the workpiece 10, it also spontaneously flows along its width. Because the workpiece 10 is relatively narrow, when the flow velocity of the polishing slurry is relatively uniform along its length, the flow velocity along its width is also relatively uniform. Therefore, the chemical polishing method of this application provides relatively uniform polishing of the entire workpiece 10. Furthermore, by incorporating the aforementioned various motion modes, such as alternating forward and reverse rotation of the workpiece or polishing slurry, or variable-speed rotation of the workpiece, the flow direction of the polishing slurry can be aligned with different parts of the workpiece's circumference. This further reduces the uneven polishing caused by slight differences in flow velocity between the front and back surfaces of the cylindrical workpiece 10, resulting in higher circumferential polishing uniformity of the workpiece 10.

[0101] Furthermore, the length of workpiece 10 can be 28–90 mm, 58–500 mm, 118–500 mm, 28–200 mm, 25–400 mm, 300–500 mm, 150–200 mm, 180–300 mm, or 58–120 mm, etc. When the workpiece length is relatively large, this polishing method has more obvious advantages in terms of workpiece polishing uniformity and stability, especially when the workpiece length is above 38 mm, or even above 50 mm, the uniformity of polishing at both ends of the support and the dimensional stability after polishing multiple supports will be better. The ratio of the length to the width of workpiece 10 can be 20–200, 30–300, 25–50, 22–100, 20–40, or 23–300, etc. The length or width of workpiece 10 can be the same or different across the entire workpiece 10, and the above values ​​can be values ​​at any part of workpiece 10 or average values.

[0102] As an example, the workpiece 10 is cylindrical and movably fitted onto the polishing rod 1421. Thus, during the polishing process of the workpiece 10, the polishing fluid can flow into the interior of the workpiece 10 to polish its inner wall. The polishing fluid can also enter the inner wall of the workpiece 10 through the perforated portions in its wall thickness for further polishing.

[0103] Specifically, the diameter of the polishing rod 1421 can be matched with the inner diameter of the workpiece 10, and the ratio of the outer diameter of the polishing rod to the inner diameter of the workpiece can be set to (0, 0.92). For example, the diameter of the polishing rod 1421 can be 0.3–18 mm, and the diameter of the workpiece 10 can be 1.0–40 mm. It should be understood that when the workpiece 10 is a tubular support, it is generally loaded into the delivery system in a radially compressed state and fixed to the implantation site in an expanded state when implanted into a living organism. The diameter of the tubular support in the chemical polishing process can be between the diameter of the compressed state and the diameter of the expanded state, or it can be equal to the diameter of either the compressed state or the expanded state. It can also be the diameter of the tubular support in the previous polishing process, such as the laser engraving process, or approximately equal to the diameter of the metal tubing used to manufacture the tubular support. When the diameter of the connecting rod is less than 0.3 mm... If the polishing rod 1421 is too thin, it is prone to bending or breaking, making it difficult to maintain a stable tension, affecting the positioning of the workpiece 10, thus impacting the polishing effect and potentially damaging the workpiece 10. When the diameter of the polishing rod 1421 is greater than 18mm, it becomes too thick, which is detrimental to the uniform polishing of the workpiece 10. Further, the diameter of the polishing rod 1421 can be 0.5–18mm, 0.5–15mm, 1–16mm, 1.5–10mm, 0.5–8mm, 2.5–10mm, or 1.5–5mm. Even further, the diameter of the polishing rod 1421 can be, but is not limited to, 0.3mm, 0.5mm, 0.8mm, 1mm, 1.5mm, 2.5mm, 3mm, 5mm, 8mm, 10mm, 12mm, 15mm, 16mm, or 18mm.

[0104] On the other hand, as examples, the maximum contact area between the workpiece 10 and the polishing rod 1421 is 0.01 to 0.5 times the surface area of ​​the workpiece 10. It should be understood that the surface area of ​​the workpiece 10 refers to the surface area of ​​the surfaces where the polishing rod 1421 and the workpiece 10 can make contact. For example, when the polishing rod 1421 passes through the axial center of the hollow tubular workpiece 10, the inner wall of the workpiece 10 can make contact with the polishing rod 1421, and the surface area of ​​the workpiece 10 is the surface area of ​​the inner wall. The maximum contact area can be the contact area between the workpiece 10 and the polishing rod 1421 when the workpiece 10 is in a stationary state after being fitted onto the polishing rod 1421; that is, the maximum contact area that the polishing rod 1421 and the workpiece 10 can have when they come into contact. By setting the maximum contact area between the workpiece 10 and the polishing rod 1421 to 0.01 to 0.5 times the surface area of ​​the workpiece 10, the workpiece 10 can be stably limited while minimizing contact between the workpiece 10 and the polishing rod 1421, thus reducing uneven polishing caused by contact. Furthermore, the contact area between the connecting part 142 and the workpiece 10 can be 0.02 to 0.5 times, 0.04 to 0.4 times, 0.05 to 0.3 times, 0.1 to 0.5 times, 0.2 to 0.25 times, 0.05 to 0.1 times, 0.1 to 0.25 times, 0.4 to 0.5 times, etc., of the surface area of ​​the workpiece 10.

[0105] Furthermore, the driving device can cause the contact area between the workpiece 10 and the polishing rod 1421 to vary within the range of 0 to the maximum contact area. Please refer to Figures 2 and 3 for comparison. When the workpiece 10 rotates around the first axis S1 or the workpiece mounting axis S3, or when the stirring element 131 rotates around the second axis S2 to drive the polishing liquid to flow towards the workpiece 10, since the workpiece 10 is movably sleeved on the polishing rod 1421, the two ends of the workpiece 10 in the long axis direction will deflect at a small angle relative to the center, but the deflection angle is still within the range of 0 to 10°. Therefore, the distances between the two ends of the workpiece 10 and the first axis S1 and the second axis S2 can still be considered to be basically consistent, so as to maintain the consistency of the polishing liquid flow rate in the axial direction. At the same time, the contact position between the workpiece 10 and the polishing rod 1421 changes, and even a partial or complete axial area of ​​the workpiece 10 may temporarily lose contact with the polishing rod 1421. This causes the contact area to change to be less than the maximum contact area or even to become zero. As a result, the total contact time between each point on the contact surface of the workpiece 10 and the polishing rod 1421 tends to be more balanced, and the time that each point is subjected to the polishing liquid at the same flow rate also tends to be equal, making the polishing effect of the workpiece 10 more uniform overall.

[0106] Furthermore, the length of the polishing rod 1421 can be greater than the length of the workpiece 10. This facilitates the axial positioning of the polishing rod 1421 on the workpiece while maintaining a certain degree of mobility, preventing the axial ends of the workpiece 10 from being tightly pressed against the workpiece clamp, thus ensuring a uniform polishing effect at its ends. The ratio of the polishing rod length to the workpiece length can be 1.05-1.5 or 1.05-1.2. For example, the length of the polishing rod 1421 can be 20-1000mm, 15-500mm, 20-300mm, 50-400mm, 30-700mm, or 15-200mm, etc., and the length of the support is within the above ratio range and the range corresponding to the polishing rod length, making it suitable for polishing workpieces 10 of different lengths.

[0107] Furthermore, the distance between the agitator 131 and the workpiece 10 is 0.1–150 mm. When the distance between the agitator 131 and the workpiece 10 is less than 0.1 mm, the agitator 131 and the workpiece 10 will come into contact. When the distance between the agitator 131 and the workpiece 10 is greater than 150 mm, the flow rate of the polishing liquid to the workpiece 10 is relatively slow and the change in flow direction is relatively large, affecting the polishing efficiency and effect. Furthermore, the distance between the agitator 131 and the workpiece 10 can be, but is not limited to, 0.5–100 mm, 0.5–80 mm, 0.5–50 mm, 1–40 mm, 20–50 mm, 10–50 mm, 5–20 mm, 30–40 mm, 20–40 mm, or 10–20 mm. The setting of this interval distance allows the polishing slurry to be less affected by the molecular forces between solutions, gravity, and other forces during the process of flowing from the agitator 131 to the workpiece 10. The flow rate and direction output from the agitator 131 will not change significantly when it reaches the workpiece 10. As a result, the flow rate and direction of the polishing slurry when it reaches the workpiece 10 are relatively uniform, and the polishing effect is more ideal. This is especially suitable when there is no additional driving force to drive the workpiece 10 to rotate, or when the workpiece 10 itself has a low rotation speed, so that the agitator 131 can have a more effective influence on the flow of polishing slurry around the workpiece 10.

[0108] In some possible embodiments, the spacing between the agitator 131 and the workpiece 10 is such that the agitator 131 has a fan-bladed structure, as shown in Figure 2. The agitator 131 includes an agitator shaft 1311 and at least one fan blade 1312. The fan blade 1312 is fixedly connected to the agitator shaft 1311, with the axis of the agitator shaft 1311 serving as a second axis S2, corresponding to an angle of 0 to 10° between the agitator shaft 1311 and the long axis of the workpiece 10. Each fan blade 1312 extends along the length of the agitator shaft 1311. The outer edge 1310 of the fan blade is preferably a straight edge, corresponding to the straight edge of the workpiece 10. Specifically, the spacing between the outer edge 1310 of the fan blade 1312 and the workpiece 10 remains equal in the axial direction of the workpiece. As an example, when the edge of the workpiece 10 is straight, the width w of the fan blade 1312 remains substantially consistent along the axial direction of the agitator shaft 1311. In this example, the distance between the agitator 131 and the workpiece 10 can be defined as the interval between the blade edge 1310 and the workpiece 10.

[0109] Assume the distance from the first end P1 to the second end P2 of the workpiece is the workpiece length L, and the distance from the first end T1 to the second end T2 of the fan blade is the fan blade length L2. When L2 is slightly less than or greater than L (L2 is 0.8 to 1.5 times L, or L2 is 0.9 to 1.5 times L, or L2 is 0.95 to 1.5 times L), the flow area generated by the fan blade 1312 driving the polishing fluid 90 covers the entire length range of the workpiece 10, and the spacing D1 between the fan blade edge 1310 and the workpiece 10 is consistent in the length direction of the workpiece 10, which can further ensure that the workpiece 10 is located in the same flow velocity area in the length direction to obtain a consistent scouring speed. Setting an appropriate spacing D1 can ensure that the workpiece and the stirring component maintain a certain distance without rubbing against each other, whether stationary or in motion, thus improving the reliability of the polishing equipment. It should be understood that the spacing D1 between the fan blade edge 1310 and the workpiece 10 can be defined as the distance between the fan blade edge 1310 and the contour edge of the workpiece 10 closest to the fan blade edge 1310. It should also be understood that, for example, as shown in Figure 3, during the polishing process, the two ends of the workpiece 10 along the long axis may deflect at a small angle relative to the center, or due to the complexity of the movement within the polishing fluid, a certain degree of tilting or bending may occur, resulting in slight differences in the distances D1 and D1' between the two ends of the workpiece 10 and the stirring component 131. However, when the tilt amplitude of the workpiece 10 during the polishing process is kept within the range of 0° to 10°, the above differences have a limited impact on the polishing effect, and the standard deviation of the polishing of the workpiece 10 can still be within the standard range.

[0110] In some possible implementations, the orthographic projection of the stirring shaft 1311 of the stirring element 131 onto the straight line containing the axis of the workpiece 10 at least completely covers the axis of the workpiece 10. That is, the length of the stirring element 131 is greater than or equal to the length of the workpiece 10, and the stirring element 131 is positioned opposite to the workpiece 10. This further ensures that the flow rate and direction of the polishing liquid flowing to the workpiece 10 are relatively uniform, resulting in a better polishing effect on the workpiece 10. Furthermore, the length of the stirring element 131 can be any value within any range greater than 0.8 times the length of the workpiece 10; furthermore, the length of the stirring element 131 can be any value within any range greater than 0.85 times the length of the workpiece 10, such as any value within the range of 0.8–30 times, 1–30 times, 1.5–3 times, 1–2 times, 1.2–1.5 times, 1.2–2 times, or even 0.8–150 times the length of the workpiece 10. Furthermore, as another example, the orthographic projection of the stirring shaft 1311 of the stirring element 131 onto the straight line of the axis of the polishing rod 1421 (that is, the workpiece mounting axis S3) at least completely covers the axis of the polishing rod 1421.

[0111] In this chemical polishing method, the temperature of the polishing slurry can be maintained between 10-50℃. Within this suitable temperature range, the polishing slurry maintains relatively stable activity. Too low a temperature leads to decreased activity, while too high a temperature easily causes deactivation. Maintaining the polishing slurry temperature between 10-50℃ eliminates the influence of temperature variations on the polishing speed.

[0112] The chemical polishing method provided in this application creates a relative flow between the polishing liquid 90 and the workpiece 10, and the flow velocity of the polishing liquid 90 relative to the workpiece 10 is basically consistent in the axial direction of the workpiece 10. This allows the workpiece 10 to obtain a relatively consistent polishing effect in its axial direction, resulting in a more ideal polishing effect. It reduces manual intervention and reliance on operator experience during the polishing process, thereby improving polishing quality and efficiency. It is suitable for fine polishing of slender workpieces such as tubular supports, and can well meet the requirement of uniform polishing of slender workpieces 10.

[0113] It should be understood that when the workpiece is driven to rotate or the polishing liquid is driven to flow with a preset driving force, such as the first driving device 14 driving the workpiece 10 to rotate at a first speed, or the second driving device 13 stirring the polishing liquid at a second speed, the rotation speed of the workpiece 10 in the polishing liquid or the flow speed of the polishing liquid is affected by various factors such as the driving method, the structure of the second driving device 13, the structure of the first driving device 14, the concentration of the polishing liquid, and the intermolecular forces, and is not completely consistent with the set speed. The first speed and the second speed referred to in this application can be the set output value of the corresponding motor or the speed converted from the set output value, or the actual speed of the stirring component and the workpiece fixture, or the actual speed of the polishing liquid and the actual speed of the workpiece.

[0114] Please refer to Figure 2, which is a schematic diagram of the structure of a chemical polishing apparatus provided in one embodiment of this application. The chemical polishing apparatus 1 includes a container 12 for holding a polishing slurry 90 and a drive device (not labeled) for driving the polishing slurry to flow relative to the workpiece in a set mode, ensuring that the flow velocity of the polishing slurry relative to the workpiece remains substantially consistent along the axial direction of the workpiece. The drive device includes a second drive device 13 and a first drive device 14. The first drive device 14 is used to mount a workpiece clamp (Figure 2 uses a polishing rod 1421 as an example) and drive the workpiece 10, which is constrained by the workpiece clamp, to rotate within the polishing slurry 90. The second drive device 13 is used to agitate the polishing slurry 90. The second drive device 13 includes a stirring element 131 located in the polishing slurry 90 for agitation, and a stirring element drive unit 132 connected to the stirring element 131 and used to drive the stirring element 131 according to a set mode. The stirring element 131 preferably covers the entire length of the workpiece 10, that is, the length of the stirring element 131 extending in the polishing slurry is equal to or greater than the length of the workpiece 10, and is preferably arranged side-by-side facing each other. The central axis of the stirring shaft 1311 of the stirring element 131 coincides with the second axis S2. That is, the stirring element 131 rotates around its own central axis to drive the polishing liquid to rotate and flow towards the workpiece 10. The workpiece 10 can rotate around the first axis S1, which is a certain distance from the workpiece mounting axis S3, or it can rotate around the workpiece mounting axis S3. The stirring element drive unit 132 can be any type of drive motor and is preferably placed outside the container 12. The polishing speed can be adjusted by controlling the rotational speed of the drive motor. The container 12 can specifically be a chemical polishing tank. The examples of the angular relationships and rotational speeds of the axes described above are applicable to the chemical polishing equipment of this embodiment and other embodiments of this application, and will not be repeated here.

[0115] In some possible implementations, the polishing rod 1421 is horizontally fixed to the first driving device 14, and limiting members 1422 are sleeved at both ends of the polishing rod 1421. The polishing rod 1421 suspends the workpiece 10 horizontally in the polishing liquid 90. The polishing rod 1421 can limit the radial movement range and possible deflection of the workpiece 10, and the limiting members 1422 at both ends can limit the axial movement range of the workpiece 10. The length of the polishing rod 1421 located between the limiting members 1422 at both ends is greater than the length of the workpiece 10, so that the workpiece 10 has a certain axial movement margin. This can avoid insufficient polishing of local areas of the workpiece 10 caused by the two ends of the workpiece 10 being in constant contact with the limiting members 1422 during the polishing process. At the same time, because it is limited to a suitable range of movement, it ensures that all parts of the workpiece 10 are in the same flow velocity region in the axial direction. The ratio of the length of the polishing rod between the limiting members 1422 to the length of the workpiece is 1.05-1.5. In addition, by using different limiting members 1422, workpieces 10 of different sizes can be limited, thus improving the versatility of the equipment.

[0116] As an example, the limiting member 1422 can be a retaining ring or a stop block. It is connected to the polishing rod 1421 by binding or threading. The number of limiting members 1422 can be at least one, and the number of limiting members 1422 can be adapted to the number of workpieces 10 connected to the polishing rod 1421, the connection method between the polishing rod 1421 and the workpieces 10, etc., without specific limitation. For example, after the workpiece 10 is sleeved on the polishing rod 1421 in the horizontal direction, limiting members 1422 can be provided at both ends of the polishing rod 1421 to limit the position of the workpiece 10.

[0117] As one example of a chemical polishing apparatus using the aforementioned chemical polishing method, the workpiece 10 of the chemical polishing apparatus 1 rotates around its axis so that the workpiece 10 is not only located in the polishing liquid area with a basically uniform flow rate in its long axis direction, but also achieves a more efficient polishing efficiency because the stirring element 131 also rotates to stir the polishing liquid. This causes the contact position between the workpiece 10 and the polishing rod 1421 to change over time, reducing the contact area or even causing them to lose contact. As a result, all parts of the inner and outer surfaces of the workpiece 10 in the long axis direction and circumferential direction can be fully exposed to the polishing liquid area with a basically uniform flow rate during the polishing duration, resulting in a more uniform polishing effect and high polishing efficiency.

[0118] As an example, the polishing rod 1421 can be made of stainless steel wire with a diameter in the millimeter range, such as a stainless steel wire with a diameter of 0.5 mm. Of course, the polishing rod 1421 can also be made of other materials, with the diameter as shown in the previous example. The container 12 can be configured in any shape with a cavity and an opening communicating with the cavity, for the workpiece 10, polishing fluid 90, etc., to enter and exit. If the container 12 is rectangular, the opening can be located on the side wall or top of the container 12. The container 12 may also include a lid for sealing the opening. The container 12 can also be made in various shapes such as cylindrical, frustum, and prism. The container 12 can be placed on the operating table 11.

[0119] In some alternative designs, the fan blade 1312 can be a rectangular metal sheet or alloy plate arranged along the stirring shaft 1311. The stirring element 131 can be a one-piece structure or a detachable structure. The workpiece 10 and the stirring element 131 can share a single stirring drive unit 132 (such as a motor) for driving rotation, or they can be driven independently by different motors.

[0120] Please refer to Figure 4, which is a schematic diagram of the structure of a chemical polishing apparatus according to another embodiment of this application. The chemical polishing apparatus 2 has a generally similar structure to the chemical polishing apparatus 1, the main difference being that the first driving device 24 has a structure that simultaneously loads multiple workpieces 10 and drives the multiple workpieces 10 to rotate coaxially. Specifically, the first driving device 24 includes a clamping drive unit 240, a clamping shaft 241, a workpiece clamp 242, and a mounting member 243. The central axis of the clamping shaft 241 serves as the first axis S1 around which the workpiece 10 rotates, and the clamping drive unit 240 drives the clamping shaft 241 to rotate around the first axis S1 in a predetermined pattern. The workpiece clamp 242 includes multiple polishing rods 2421, which are fixed by the mounting member 243 and arranged parallel and spaced apart from the clamping shaft 241. Each polishing rod is used to mount at least one workpiece 10. Furthermore, multiple polishing rods 2421 are arranged parallel to the fixture shaft 241 at equal or unequal distances, so that multiple workpieces 10 can not interfere with each other during the polishing process, and the trajectories generated by the multiple workpieces 10 rotating around the first axis S1 are the same, thus obtaining a consistent polishing effect.

[0121] As an example, the first driving device 24 includes two mounting members 243 symmetrically and spaced apart on the clamping shaft 241. The two ends of the polishing rods 2421 are respectively fixed to the two oppositely arranged mounting members 243. The mounting members 243 can be made of a hard material with good structural strength, such as connecting rods or plates. Please refer to Figure 6, which is a schematic diagram of an exemplary structure of the mounting members in the chemical polishing device 2 of this application embodiment. Figure 6 can be seen as the structure of the first driving device 24 viewed from the right side of Figure 4. The mounting member 243 can be a circular plate. The clamping shaft 241 passes through the center of the mounting member 243 and is fixed to it. The fixing method can be welding, riveting, screw locking, integral forming, etc. One end of each of the two polishing rods 2421 is fixed to two different positions on the mounting member 243, and the other end of each polishing rod is also fixed to a corresponding position on another mounting member 243, so that the two polishing rods 2421 are symmetrically distributed on both sides of the clamping shaft 241. As an example, these two positions can be the two ends of the same diameter of the mounting member 243. When the workpiece fixture 242 rotates, each polishing rod 2421 rotates around the fixture axis 241, forming the same rotation trajectory. Therefore, the workpieces 10 suspended on the polishing rods 2421 also have a consistent rotation trajectory. Although the distances between different workpieces 10 and the stirring component 231 are different at the same time, the consistency of the motion trajectory allows two workpieces 10 to alternately change their distance from the stirring component 231 within the area Z1 defined by their motion trajectories. This creates an integral effect over time, resulting in a consistent polishing amount. This further improves the polishing effect and ensures the polishing consistency of batch-polished workpieces. As an alternative, the mounting component 243 can also be a cross extension rod or similar structure.

[0122] The mounting component 243 itself can limit the workpiece 10 mounted on the polishing rod 2421 at both ends. As an example, the workpiece fixture 242 can further include one or more limiting components 2422 for further limiting the workpiece 10. Different specifications of workpieces 10 can be polished by using the same polishing rod 2421 with different limiting components 2422, thereby improving the versatility and utilization of the workpiece fixture 242.

[0123] Additionally, please refer to Figure 5, which is an enlarged cross-sectional view of an exemplary structure of the agitator 231 of the chemical polishing apparatus 2 according to an embodiment of this application. The agitator 231 includes four blades 2312 evenly distributed circumferentially along the agitator shaft 2311 and extending along the length direction of the agitator shaft 2311. Each blade 2312 has an equal length and is greater than the length of the workpiece 10, specifically 1 to 1.5 times the length of the workpiece 10, and may be further greater than the length of the polishing rod 2421, to ensure that the flowing polishing liquid generated by the agitator 2312 covers the entire length of the workpiece 10. The distance from the connection point of the blade 2312 to the outer edge of the blade 2312 is the width W of the blade 2312. Preferably, the width W of each blade is the same, and the blade width remains substantially consistent along the length direction of the agitator shaft 2311. The distance between the outer edge of the fan blade 2312 and the workpiece 10 remains equal along the length of the fan blade 2312. Furthermore, the distance between the outer edge of the fan blade 2312 and the workpiece 10 is 0.1–150 mm. As an example, the four fan blades 2312 are arranged in pairs, forming a 90° angle. Using four fan blades 2312 allows for better transmission of driving force to the polishing fluid, resulting in better stirring. The structure is also relatively simple and easy to implement.

[0124] In this application, the shape of the fan blade / stirring component can be adjusted according to the shape of the workpiece, so that the flow rate of the fluid in each part of the workpiece is basically the same, thereby ensuring the uniformity of polishing of each part of the workpiece.

[0125] The chemical polishing equipment 2 of this application has a simple and ingenious structure, is easy to operate, and well meets the requirements for uniform polishing of slender workpieces 10 and the consistency of the effect of polishing multiple workpieces at the same time.

[0126] Please refer to Figure 7, a schematic diagram of the structure of a chemical polishing apparatus provided in another embodiment of this application. The main difference between chemical polishing apparatus 3 and chemical polishing apparatus 1 is that in chemical polishing apparatus 3, the stirring element 331 and the workpiece 10 are arranged vertically and parallel in the polishing liquid. Specifically, chemical polishing apparatus 3 includes a second driving device 33 and a first driving device 34. The second driving device 33 includes a stirring element 331 and a stirring drive unit 332 for driving the stirring element 331 to rotate. The stirring element 331 is arranged vertically. Furthermore, the stirring element 331 can extend from near the liquid surface to near the bottom of the container 12. The angle between the stirring shaft 3311 and the axis of the workpiece 10 is maintained within the range of 0 to 10°, so that the polishing liquid is driven by the same power from the stirring element, which is a power output element, throughout almost the entire liquid surface height range, thereby reducing the generation of eddies. The extension direction of the fan blade 3312 is consistent with that of the stirring shaft 3311, and its specific structure can be referred to the aforementioned embodiment.

[0127] The first driving device 34 includes a fixing mechanism 340 and a workpiece clamp 342. The workpiece clamp 342 is mounted to the fixing mechanism 341 and placed vertically in the polishing liquid. The workpiece clamp 342 includes a polishing rod 3421 and a limiting member 3422. One end of the polishing rod 3421 is fixed to the fixing part 3420, and the other end is equipped with the limiting member 3422 and suspended in the polishing liquid. The limiting member 3422 is used to prevent the workpiece 10 from sliding off the polishing rod 3421. The workpiece 10 is movably sleeved on the polishing rod 3421. Optionally, in addition to fixing the workpiece clamp 342, the fixing mechanism 340 may further include a driving mechanism for driving the workpiece clamp 342 (together with the workpiece 10) to rotate in the polishing liquid.

[0128] Because of the vertical polishing method, in this embodiment, the agitator 331 of the chemical polishing equipment 3 and the workpiece 10 can enter the polishing liquid from the same direction. The relevant drive unit and fixing mechanism can be set above the container 12, so that there is no wall of the container 12 between these power mechanism / fixing mechanism and the driven / connected part (such as the agitator 331). The equipment power structure part has more options and facilitates the installation and disassembly of the workpiece 10.

[0129] Please refer to Figure 8, which is a schematic diagram of the structure of a chemical polishing device provided in another embodiment of this application. Similar to chemical polishing device 3, chemical polishing device 4 also adopts a vertical polishing method. A guide rail 45 and a slider 46 that can slide along the guide rail are provided above the polishing liquid. As an example, the guide rail 45 is a circular guide rail. The stirring member 431 is connected to the slider 46 and can move in a circle along the guide rail 45 with the slider 46. The stirring member 431 includes a stirring shaft 4311 that is vertically connected to the slider 46 and enters the polishing liquid, and multiple fan blades 4312 that are fixedly connected to the stirring shaft 4311. Multiple mounting members 4423 are used to vertically fix multiple polishing rods 4421. Multiple workpieces 10 can be movably sleeved on their respective corresponding polishing rods 4421 and are vertically limited by limiting members 4422 located below the workpieces 10.

[0130] Guided by the guide rail 45, the stirring component 431 can move around the workpiece 10 within the container 12, agitating the polishing slurry at different locations and improving its fluidity. Additionally, the mounting component 4423 can also cause the workpiece 10 to rotate off-axis via the rotation of the fixture shaft 4420. As an example, mounting components 4423 are provided at both ends and the middle along the length of the fixture shaft 4420. Some polishing rods 4421 are fixed at both ends to the two mounting components 4423 at the ends, allowing for longer workpieces 10 to be mounted. Other polishing rods 4421 can be mounted between the end mounting components 4423 and the middle mounting components 4423, allowing for shorter workpieces to be mounted. Thus, the same workpiece fixture can accommodate workpieces 10 of different lengths. Furthermore, the mounting component 4423 connected to the middle part of the clamping shaft 4420 can be fixedly connected to the clamping shaft 4420, or it can be connected by means of slide rails or clamps to achieve positional adjustment. This can meet the needs of polishing workpieces 10 of more length specifications at the same time, and improve the equipment's ability to meet more personalized polishing needs.

[0131] Please refer to Figure 9, which is a structural schematic diagram of the chemical polishing equipment and its mounting components according to another embodiment of this application. The overall structure and operating principle of the chemical polishing equipment 5 in this embodiment are roughly similar to those of the aforementioned chemical polishing equipment 2. The main difference lies in the use of multiple sets of workpiece clamps and multiple sets of fan blades to achieve simultaneous polishing of more workpieces. Specifically, the stirring component 531 and the workpiece clamp 542 are placed horizontally and parallel in the polishing tank 120, and polishing liquid is added to the polishing tank 120 as needed. The clamp shaft 5420 rotates around the first axis S1 (i.e., its own central axis). Multiple mounting components are fixed to the clamp shaft 5420 and arranged perpendicularly to it. These mounting components include a first mounting component 5423a, a second mounting component 5423b, a third mounting component 5423c, and a fourth mounting component 5423d, which are sequentially spaced along the length of the clamp shaft 5420. A first set of workpiece fixtures is fixedly connected between the first mounting component 5423a and the second mounting component 5423b, including: a first polishing rod 5421a, a second polishing rod 5421b, a third polishing rod 5421c, and a fourth polishing rod 5421d. The first polishing rod 5421a, the second polishing rod 5421b, the third polishing rod 5421c, and the fourth polishing rod 5421d are arranged in parallel pairs and are equidistant from the fixture rotation shaft 5420. Each polishing rod is used to mount the first set of workpieces, including: a first workpiece 10a, a second workpiece 10b, a third workpiece 10c, and a fourth workpiece 10d, so that each workpiece is equidistant from the fixture rotation shaft 5420.

[0132] A second set of workpiece fixtures, including a fifth polishing rod 5421e and a sixth polishing rod 5421f, is fixedly connected between the third mounting component 5423c and the fourth mounting component 5423d. The fifth polishing rod 5421e and the sixth polishing rod 5421f are arranged parallel to and equidistant from the fixture rotation shaft 5420, and are respectively used to mount the second set of workpieces, including a fifth workpiece 10e and a sixth workpiece 10f. Of course, three, four, or more polishing rods can also be mounted between the third mounting component 5423c and the fourth mounting component 5423d.

[0133] Referring again to Figure 9, the stirring shaft 5311 rotates around the second axis S2 (which is also the central axis of the stirring shaft 5311 itself). The first fan blade group 5312a and the second fan blade group 5312b are spaced apart along the stirring shaft 5311 to correspond to the first group of workpieces and the second group of workpieces, respectively. The distance between the two sets of fan blades is basically equal to the distance between the two sets of mounting components. The distance between the two sets of mounting components refers to the distance between the second mounting component 5423b and the third mounting component 5423c. The distance between the two groups of workpieces and the fixture rotating shaft 5420 can be kept basically consistent, so that the off-axis rotation trajectory of different groups of workpieces is the same, so as to obtain a consistent polishing effect in the same time. By polishing the workpieces using the equipment shown in Figure 9, multiple supports can be polished simultaneously. Not only is the polishing quality of each support comparable, that is, the polishing stability of multiple supports polished simultaneously is good, but the polishing efficiency is also greatly improved. In the same time, the polishing efficiency can be greatly improved without sacrificing the polishing quality of the workpieces.

[0134] The chemical polishing equipment 5 may further include a base 111, and a polishing tank 120 may be disposed on the base 111 and located within a frame 112. The frame 112 forms an operating space in which the main processes of the polishing process can be completed. The frame 112 may also be provided with a top rail 113, on which a shifting component 114 can reciprocate. The shifting component 114 may be a lifting mechanism, a robotic arm, etc., used to place a workpiece clamp containing a workpiece into the polishing tank 120.

[0135] Each fan blade assembly is located at the bottom of the polishing tank 120, facilitating the placement or removal of workpiece fixtures with multiple workpieces, along with the fixture shaft 5420 and various mounting components, via a movable component 114 that can move along the top track 113. This avoids manual operation in the vicinity of the polishing tank 120, and the operations of installing workpieces onto the workpiece fixtures and fixing the workpiece fixtures to the mounting components and fixture shaft can be completed in an area away from the polishing equipment, reducing potential hazards to operators. The polishing equipment 5 may further include areas for cleaning, pickling, and drying, improving the efficiency of centralized, streamlined operations and the degree of automation in processing.

[0136] Please refer to Figure 10, which is a schematic diagram of the structure of a chemical polishing device provided in another embodiment of this application. The chemical polishing device 6 is basically the same as the chemical polishing device 2 in structure and principle. The main difference is that the edge 6310 of the agitator 631 is not a straight line, but a curve that is basically consistent with the edge 200 of the workpiece 20. The distance D1 between the edge 6310 and the edge 200 of the workpiece remains basically consistent in the length direction of the workpiece, but the width of the blade is inconsistent along the axial direction of the agitator shaft. Therefore, this device 6 is suitable for processing non-cylindrical workpieces or workpieces with non-straight contour edges. Depending on the contour, length, and other characteristics of the workpiece 20, the type of corresponding blade can be changed; therefore, the chemical polishing device of this application has good versatility.

[0137] In addition, the workpiece 20 of this embodiment can also be used in conjunction with the stirring member described in FIG2 or FIG4, FIG7, FIG9, or conversely, a cylindrical or straight-edged workpiece 10 can be used in conjunction with a stirring member 631 with curved edges to obtain the desired specific polishing effect.

[0138] Although some embodiments of the chemical polishing equipment and method of this application have been described primarily using slender, hollowed-out workpieces as examples, the chemical polishing equipment and method of this application are applicable to workpieces of various shapes, such as sheet-like, plate-like, columnar, or cylindrical workpieces, and can also be applied to relatively short and thick hollowed-out workpieces, such as workpieces with an aspect ratio of less than 2. The workpiece can be a solid structure or include hollow structures. Of course, the workpieces for which the chemical polishing method and equipment of this application are applicable are not limited to medical device lumens and stents; they are also applicable to other medical device workpieces, and even precision micro-workpieces (such as wafers) in other technical fields. It should be understood that many alternative solutions can be derived under the concept of this invention. For example, as another example, multiple workpieces can be installed simultaneously on the same polishing rod along its length, and the multiple workpieces can be separated from each other by isolation members or limiting members; for another example, multiple sets of stirring members can be arranged in parallel below the workpiece, and the multiple sets of stirring members can be located at the same horizontal position or the same vertical position; or, the number of stirring members can be at least two, and the stirring members can be arranged at intervals along the circumference of the workpiece; or, although the above examples of horizontal polishing and vertical polishing have been exemplified, the chemical polishing equipment of this application also supports polishing of the workpiece and stirring members in parallel at an angle, depending on the situation; for another example, although the polishing rod is used to limit the workpiece to maintain its relative position during the polishing process, a magnetic levitation control device can also be used as the workpiece clamp and driving device to achieve non-contact limiting and motion control with the workpiece; and so on, which will not be described in detail here.

[0139] The embodiments and examples of this application also provide a lumen stent 10 prepared by a chemical polishing method. This lumen stent is characterized by its small size and slender shape. Specifically, the lumen stent 10 prepared by this method is a tubular body with a hollowed-out pattern, and its cross-sectional profile can be a roughly circular, elliptical, or other closed, smooth curve. The lumen stent 10 is made of an absorbable material, preferably an iron-based absorbable material, specifically a nitrided iron-based absorbable lumen stent, or other types of absorbable materials such as iron alloys, aluminum alloys, magnesium alloys, and zinc alloys. The prepared lumen stent 10 has a length of 8–500 mm, preferably 20–200 mm. In the expanded state, the ratio of the length of the lumen stent to the diameter of the lumen stent cross-section (i.e., the length-to-width ratio) is 1–150. Its wall thickness ranges from 30 to 500 μm. Depending on the application, it can be 45–450 μm, 45–400 μm, 45–350 μm, 45–300 μm, 45–250 μm, 45–200 μm, 45–70 μm, 60–85 μm, 70–120 μm, 90–200 μm, 130–200 μm, 150–250 μm, etc. The lumen stent prepared by this method has a wall thickness removal rate (i.e., the reduction in wall thickness after polishing relative to the wall thickness before polishing) of 5% to 95%, preferably 30% to 55%, with a polishing standard deviation within 5 μm. This results in a lumen stent with a thinner wall thickness and better polishing uniformity compared to existing technologies. In contrast, the wall thickness removal rate of nickel-titanium alloy (non-absorbable) stents using electrochemical polishing in existing technologies is generally within 10%. Exceeding this value results in significantly greater polishing at both ends than in the middle, causing uneven wall thickness and leading to unqualified polishing. The chemical polishing method and equipment of this application are particularly suitable for preparing iron-based absorbable lumen stents, a new product, and are a key process for producing qualified iron-based absorbable stents.

[0140] The specific implementation method of the chemical polishing method and chemical polishing equipment 1 of this application will be described in detail below with reference to embodiments and comparative examples. In the following embodiments, the diameter of the lumen support is the processing diameter. Example 1

[0141] In this embodiment, a tubular support is used as the workpiece 10 to be polished. Specifically, an iron-based tubular support with a length of 38 mm and a diameter of 1.6 mm is used. The single-sided polishing amount of the tubular support is 12 μm, and the ratio of the outer diameter of the polishing rod to the inner diameter of the support is 0.45.

[0142] The workpiece 10 is polished using the chemical polishing equipment 3 shown in Figure 7, with the polishing solution temperature maintained at 25°C. The stirring component 331 is driven to rotate clockwise at a speed of 540 rpm. The workpiece 10 is driven to rotate in different directions at a speed of 60 rpm, with clockwise and counterclockwise rotations lasting 1 second and 0.1 seconds respectively.

[0143] The target dimensions for the polished lumen stents were: average rod width of 96 μm and average wall thickness of 55 μm. Thirty stents were polished using the same method and equipment, and data were statistically analyzed after polishing. The results showed that the average rod width of the polished lumen stents was 96 μm with a standard deviation of 4.61 μm; the average wall thickness was 55 μm with a standard deviation of 4.89 μm, and the stent surface had high gloss. Example 2

[0144] Polishing was performed using an iron-based tubular support with a length of 58 mm and a diameter of 1.6 mm. The polishing depth on one side of the support was 12 μm, and the ratio of the outer diameter of the polishing rod to the inner diameter of the support was 0.45.

[0145] Chemical polishing was performed using the chemical polishing equipment 5 shown in Figure 9. The temperature of the polishing solution was maintained at 25°C, and the stirring component 231 was driven to rotate clockwise at a speed of 400 rpm. The workpiece 10 was driven to rotate clockwise at a speed of 150 rpm, alternating between rotation and stop, with a driving time of 1 second and a stopping time of 0.1 seconds.

[0146] The target dimensions of the lumen stent after polishing were: average rod width of 105 μm and average wall thickness of 55 μm. Thirty stents were polished using the above method and equipment, and data were statistically analyzed for the polished 30 lumen stents. The average rod width of the polished lumen stents was 105 μm with a standard deviation of 1.62 μm; the average wall thickness was 55 μm with a standard deviation of 1.91 μm, and the stent surface had a high gloss. Example 3

[0147] Polishing was performed using an iron-based tubular support with a length of 78 mm and a diameter of 1.6 mm. The polishing depth on one side of the support was 12 μm, and the ratio of the outer diameter of the polishing rod to the inner diameter of the support was 0.8.

[0148] Chemical polishing was performed using the chemical polishing equipment 2 shown in Figure 4. The temperature of the polishing solution was maintained at 25°C. The drive fan blade 2312 was rotated counterclockwise at a speed of 320 rpm. The drive workpiece 10 was driven to move clockwise at a speed of 150 rpm in an alternating rotation and stop manner for 2.5 minutes, and the drive was stopped for 2 seconds.

[0149] The target dimensions of the lumen stent after polishing were: average rod width of 105 μm and average wall thickness of 55 μm. Thirty stents were polished using the above method and equipment, and data were statistically analyzed for the 30 polished lumen stents. The average rod width of the polished lumen stents was 103 μm with a standard deviation of 5.95 μm; the average wall thickness was 54 μm with a standard deviation of 5.69 μm, and the surface gloss of the stents was generally moderate. Example 4

[0150] Polishing was performed using an iron-based tubular support with a length of 118 mm and a diameter of 2 mm. The polishing depth on one side of the support was 12 μm, and the ratio of the outer diameter of the polishing rod to the inner diameter of the support was 0.5.

[0151] Chemical polishing is performed using the chemical polishing equipment 2 shown in Figure 4, with the polishing solution temperature maintained at 25°C. The fan blade 2312 rotates clockwise at 250 rpm. The workpiece 10 is driven to rotate at 180 rpm, stopping and changing direction. It rotates clockwise for 1 second, stops for 0.5 seconds, then rotates counter-clockwise for 1 second, stops again for 0.5 seconds, and repeats the cycle.

[0152] The target dimensions of the lumen stent after polishing were: average rod width of 105 μm and average wall thickness of 55 μm. Thirty stents were polished using the above method and equipment, and data were statistically analyzed for the polished 30 lumen stents. The average rod width of the polished lumen stents was 103 μm with a standard deviation of 3.53 μm; the average wall thickness was 53 μm with a standard deviation of 3.16 μm, and the stent surface had high gloss. Example 5

[0153] Polishing was performed using an iron-based tubular support with a length of 58 mm and a diameter of 2 mm. The polishing depth on one side of the support was 12 μm, and the ratio of the outer diameter of the polishing rod to the inner diameter of the support was 0.45.

[0154] Chemical polishing was performed using the chemical polishing equipment 2 shown in Figure 4. The temperature of the polishing solution was maintained at 25°C. The fan blades were set to rotate counterclockwise at a speed of 37.5 rpm, and the workpiece 10 was set to rotate clockwise at a speed of 200 rpm, alternating between rotation and stop. Each rotation consisted of 4 stops, with each stop lasting 0.1 seconds.

[0155] The target dimensions of the lumen stent after polishing were: average rod width of 105 μm and average wall thickness of 79 μm. Thirty stents were polished using the same method and equipment as described above, and data were statistically analyzed. The average rod width of the polished lumen stents was 105 μm with a standard deviation of 2.55 μm; the average wall thickness was 78 μm with a standard deviation of 2.26 μm. Additionally, the polishing data obtained using the chemical polishing equipment 5 shown in Figure 9, with the same parameters as in this example, were essentially the same as in this example, and the relevant data will not be listed separately. The stent surface showed high gloss. Example 6

[0156] Polishing was performed using an iron-based tubular support with a length of 58 mm and a diameter of 2 mm. The polishing depth on one side of the support was 12 μm, and the ratio of the outer diameter of the polishing rod to the inner diameter of the support was 0.45.

[0157] Chemical polishing was performed using the chemical polishing equipment 2 shown in Figure 4. The temperature of the polishing solution was maintained at 25°C. The fan blades remained stationary, meaning the rotation speed of the agitator was 0 rpm. The workpiece 10 was set to rotate clockwise at a speed of 150 rpm, alternating between rotation and stop, stopping once every 90° (1 / 4 turn), with each stop lasting 0.1 seconds.

[0158] The target dimensions of the lumen stent after polishing were: average rod width of 105 μm and average wall thickness of 79 μm. Thirty stents were polished using the same method and equipment, and data were statistically analyzed. The results showed that the average rod width of the polished lumen stents was 105 μm with a standard deviation of 1.93 μm; the average wall thickness was 78 μm with a standard deviation of 3.05 μm.

[0159] It should be noted that the fan blade speed is 0 in this example. Therefore, in addition to using the chemical polishing device 2 in Figure 4, another chemical polishing device can be used, which omits the second drive device 23 from the chemical polishing device 2 in Figure 4, resulting in a high gloss on the support surface. Example 7

[0160] Polishing was performed using an iron-based tubular support with a length of 23 mm and a diameter of 3.5 mm. The single-sided polishing depth of the support was 35 μm, and the ratio of the outer diameter of the polishing rod to the inner diameter of the support was 0.45.

[0161] Chemical polishing is performed using the chemical polishing equipment 5 shown in Figure 9, with the polishing solution temperature at 25°C. The fan blade 2312 rotates clockwise at 400 rpm. The workpiece 10 is driven to rotate at 150 rpm, stopping and changing direction. It rotates clockwise for 1 second, stops for 0.5 seconds, then rotates counter-clockwise for 1 second, stops again for 0.5 seconds, and repeats the cycle.

[0162] The target dimensions of the lumen stent after polishing were: average rod width of 330 μm and average wall thickness of 232 μm. Thirty stents were polished using the above method and equipment, and data were statistically analyzed for the polished 30 lumen stents. The average rod width of the polished lumen stents was 332 μm with a standard deviation of 7.15 μm; the average wall thickness was 229 μm with a standard deviation of 7.53 μm, and the stent surface had a high gloss. Example 8

[0163] Polishing was performed using an iron-based tubular support with a length of 23 mm and a diameter of 3.5 mm. The single-sided polishing depth of the support was 35 μm, and the ratio of the outer diameter of the polishing rod to the inner diameter of the support was 0.45.

[0164] Chemical polishing is performed using the chemical polishing equipment 2 shown in Figure 4, with the polishing solution temperature at 25°C. The fan blades 2312 rotate clockwise at 400 rpm. The workpiece 10 is driven to rotate at 150 rpm, stopping and changing direction, rotating clockwise for 1 second, then stopping for 1 second, repeating this cycle.

[0165] The target dimensions of the lumen stent after polishing were: average rod width of 330 μm and average wall thickness of 232 μm. Thirty stents were polished using the above method and equipment, and data were statistically analyzed for the 30 polished lumen stents. The average rod width of the polished lumen stents was 330 μm with a standard deviation of 5.15 μm; the average wall thickness was 231 μm with a standard deviation of 5.53 μm, and the stent surface had a high gloss. Example 9

[0166] Polishing was performed using an iron-based tubular support with a length of 23 mm and a diameter of 3.5 mm. The single-sided polishing depth of the support was 35 μm, and the ratio of the outer diameter of the polishing rod to the inner diameter of the support was 0.25.

[0167] Chemical polishing is performed using the chemical polishing equipment 2 shown in Figure 4, with the polishing solution temperature at 25°C. The fan blades 2312 rotate clockwise at 400 rpm. The workpiece 10 is driven to rotate at 150 rpm, stopping and changing direction, rotating clockwise for 1 second, then stopping for 0.1 seconds, repeating this cycle.

[0168] The target dimensions of the lumen stent after polishing were: average rod width of 96 μm and average wall thickness of 55 μm. Thirty stents were polished using the above method and equipment, and data were statistically analyzed for the polished 30 lumen stents. The average rod width of the polished lumen stents was 95 μm with a standard deviation of 3.98 μm; the average wall thickness was 58 μm with a standard deviation of 3.47 μm, and the stent surface had a high gloss. Example 10

[0169] Polishing was performed using an iron-based tubular support with a length of 58 mm and a diameter of 1.6 mm. The polishing depth on one side of the support was 12 μm, and the ratio of the outer diameter of the polishing rod to the inner diameter of the support was 0.01.

[0170] Chemical polishing was performed using the chemical polishing equipment 5 shown in Figure 9. The temperature of the polishing solution was maintained at 25°C, and the stirring component 231 was driven to rotate clockwise at a speed of 1200 rpm. The workpiece 10 was driven to rotate clockwise at a speed of 120 rpm, alternating between rotation and stop, with a driving time of 0.1 seconds and a stopping time of 0.1 seconds.

[0171] The target dimensions of the polished lumen stents were: average rod width of 105 μm and average wall thickness of 55 μm. Thirty stents were polished using the same method and equipment, and data were statistically analyzed. The average rod width of the polished lumen stents was 104 μm with a standard deviation of 2.05 μm; the average wall thickness was 53 μm with a standard deviation of 2.08 μm, and the stent surface exhibited extremely high gloss. Example 11

[0172] Polishing was performed using an iron-based tubular support with a length of 58 mm and a diameter of 1.6 mm. The polishing depth on one side of the tubular support was 12 μm, and the ratio of the outer diameter of the polishing rod to the inner diameter of the support was 0.2.

[0173] Chemical polishing was performed using the chemical polishing equipment 5 shown in Figure 9. The temperature of the polishing solution was maintained at 25°C, and the stirring component 231 was driven to rotate clockwise at a speed of 400 rpm. The workpiece 10 was driven to rotate clockwise at a speed of 400 rpm, alternating between rotation and stop, with a driving time of 0.1 seconds and a stopping time of 0.1 seconds.

[0174] The target dimensions of the lumen stent after polishing were: average rod width 105 μm and average wall thickness 55 μm. Thirty stents were polished using the above method and equipment, and data were statistically analyzed for the 30 polished lumen stents. The average rod width of the polished lumen stents was 104 μm with a standard deviation of 3.43 μm; the average wall thickness was 54 μm with a standard deviation of 3.52 μm, and the surface gloss of the stents was generally moderate. Example 12

[0175] Polishing was performed using an iron-based tubular support with a length of 118 mm and a diameter of 2 mm. The polishing depth on one side of the support was 12 μm, and the ratio of the outer diameter of the polishing rod to the inner diameter of the support was 0.45.

[0176] Chemical polishing is performed using the chemical polishing equipment 2 shown in Figure 4, with the polishing solution temperature maintained at 25°C. The fan blade 2312 rotates clockwise at 250 rpm. The workpiece 10 is driven to rotate at 180 rpm, stopping and changing direction, rotating clockwise for 6 seconds, stopping for 0.2 seconds, then rotating counter-clockwise for 0.3 seconds, stopping again for 0.1 seconds, and repeating the cycle.

[0177] The target dimensions of the lumen stent after polishing were: average rod width of 105 μm and average wall thickness of 55 μm. Thirty stents were polished using the above method and equipment, and data were statistically analyzed for the polished 30 lumen stents. The average rod width of the polished lumen stents was 103 μm with a standard deviation of 6.05 μm; the average wall thickness was 54 μm with a standard deviation of 5.96 μm, and the stent surface had high gloss. Example 13

[0178] Polishing was performed using an iron-based tubular support with a length of 118 mm and a diameter of 2 mm. The polishing depth on one side of the support was 12 μm, and the ratio of the outer diameter of the polishing rod to the inner diameter of the support was 0.45.

[0179] Chemical polishing is performed using the chemical polishing equipment 2 shown in Figure 4, with the polishing solution temperature maintained at 25°C. The fan blade 2312 rotates clockwise at 250 rpm. The workpiece 10 is driven to rotate at 180 rpm, stopping and changing direction, rotating clockwise for 3 seconds, stopping for 0.1 seconds, then rotating counter-clockwise for 0.3 seconds, and stopping again for 0.1 seconds, repeating the cycle.

[0180] The target dimensions of the lumen stent after polishing were: average rod width of 105 μm and average wall thickness of 55 μm. Thirty stents were polished using the above method and equipment, and data were statistically analyzed for the polished 30 lumen stents. The average rod width of the polished lumen stents was 103 μm with a standard deviation of 5.05 μm; the average wall thickness was 54 μm with a standard deviation of 5.38 μm, and the stent surface had high gloss. Example 14

[0181] Polishing was performed using an iron-based tubular support with a length of 118 mm and a diameter of 2 mm. The polishing depth on one side of the support was 12 μm, and the ratio of the outer diameter of the polishing rod to the inner diameter of the support was 0.9.

[0182] Chemical polishing is performed using the chemical polishing equipment 2 shown in Figure 4, with the polishing solution temperature maintained at 25°C. The fan blade 2312 rotates clockwise at 250 rpm. The workpiece 10 is driven to rotate at 180 rpm, stopping and changing direction. It rotates clockwise for 1 second, stops for 0.5 seconds, then rotates counter-clockwise for 1 second, stops again for 0.5 seconds, and repeats the cycle.

[0183] The target dimensions of the lumen stent after polishing were: average rod width of 105 μm and average wall thickness of 55 μm. Thirty stents were polished using the above method and equipment, and data were statistically analyzed for the 30 polished lumen stents. The average rod width of the polished lumen stents was 103 μm with a standard deviation of 4.15 μm; the average wall thickness was 53 μm with a standard deviation of 4.67 μm, and the surface gloss of the stents varied. Example 15

[0184] Polishing was performed using an iron-based tubular support with a length of 118 mm and a diameter of 2 mm. The polishing depth on one side of the support was 12 μm, and the ratio of the outer diameter of the polishing rod to the inner diameter of the support was 0.5.

[0185] Chemical polishing is performed using the chemical polishing equipment 2 shown in Figure 4, with the polishing solution temperature maintained at 25°C. The fan blade 2312 rotates clockwise at 800 rpm. The workpiece 10 is driven to rotate at 300 rpm, stopping and changing direction. It rotates clockwise for 1 second, stops for 0.5 seconds, then rotates counter-clockwise for 0.25 seconds, stops again for 0.5 seconds, and repeats the cycle.

[0186] The target dimensions of the lumen stents after polishing were: average strut width of 105 μm and average wall thickness of 55 μm. Thirty stents were polished using the same method and equipment, and data were statistically analyzed. The average strut width of the polished lumen stents was 103 μm with a standard deviation of 2.95 μm; the average wall thickness was 53 μm with a standard deviation of 2.97 μm, and the surface gloss of the stents was moderate.

[0187] Comparative Example 1

[0188] A tubular support was used as the workpiece 10 to be polished. Specifically, an iron-based tubular support with a length of 58 mm and a diameter of 1.6 mm was used. The polishing amount on one side of the support was 12 μm.

[0189] The polishing slurry temperature is maintained at 25℃. A magnetic rotor at the bottom of the container is used to stir the polishing slurry, rotating clockwise at 400 rpm. The workpiece 10 is driven to rotate clockwise at 60 rpm, alternating between rotation and stop, with a rotation time of 1 second and a stop time of 0.1 seconds.

[0190] The target dimensions of the lumen stent after polishing were: average strut width of 105 μm and average wall thickness of 55 μm. Thirty stents were polished using the same method, and data were statistically analyzed. The average strut width of the polished lumen stents was 102 μm with a standard deviation of 9.72 μm; the average wall thickness was 54 μm with a standard deviation of 7.47 μm. (Comparative Example 2)

[0191] A tubular support was used as the workpiece 10 to be polished. Specifically, an iron-based tubular support with a length of 118 mm and a diameter of 1.6 mm was used. The polishing amount on one side of the support was 12 μm.

[0192] The polishing slurry temperature is maintained at 25℃. A magnetic rotor at the bottom of the container is used to stir the polishing slurry, rotating clockwise at 540 rpm. The workpiece 10 is driven to alternately rotate clockwise at 60 rpm and stop, with each rotation lasting 0.1 seconds.

[0193] The target dimensions of the lumen stent after polishing were: average strut width of 105 μm and average wall thickness of 55 μm. Thirty stents were polished using the same method, and data were statistically analyzed. The average strut width of the polished lumen stents was 102 μm with a standard deviation of 12.76 μm; the average wall thickness was 57 μm with a standard deviation of 12.53 μm. (Comparative Example 3)

[0194] Polishing was performed using an iron-based tubular support with a length of 23 mm and a diameter of 3.5 mm, with a single-sided polishing depth of 35 μm.

[0195] The polishing slurry temperature is maintained at 25℃. A magnetic rotor at the bottom of the container is used to stir the polishing slurry, rotating clockwise at 400 rpm. The workpiece 10 is driven to rotate clockwise at 60 rpm, alternating between rotation and stop for 1 second each time.

[0196] The target dimensions of the lumen stent after polishing were: average strut width of 96 μm and average wall thickness of 55 μm. Thirty stents were polished using the same method and equipment, and data were statistically analyzed. The average strut width of the polished lumen stents was 95 μm with a standard deviation of 9.35 μm; the average wall thickness was 55 μm with a standard deviation of 9.53 μm.

[0197] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Rather, any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A chemical polishing method, characterized in that, include: Immerse the workpiece in the polishing solution; The polishing fluid is driven to flow relative to the workpiece in a set mode, and the flow velocity of the polishing fluid relative to the workpiece is kept substantially consistent along the axial direction of the workpiece.

2. The chemical polishing method according to claim 1, characterized in that, The step of driving the polishing fluid to flow relative to the workpiece in a set mode specifically includes: The workpiece is driven to rotate about a first axis in the polishing slurry at a first rotational speed, the first axis being at an angle of 0 to 10° with respect to the major axis of the workpiece; and / or the polishing slurry is driven to rotate about a second axis at a second rotational speed, the second axis being at an angle of 0 to 10° with respect to the major axis of the workpiece.

3. The chemical polishing method according to claim 2, characterized in that, The setting modes include: The workpiece is driven to rotate at a uniform or variable speed, the first rotational speed being 0 to 500 rpm; and / or the polishing slurry is driven to rotate at a uniform or variable speed, the second rotational speed being 0 to 1200 rpm.

4. The chemical polishing method according to claim 3, characterized in that, The first rotational speed is 40 to 450 rpm and / or the second rotational speed is 37.5 to 1000 rpm; The method of driving the workpiece to rotate at varying speeds includes: driving the workpiece to rotate in an alternating manner of rotation and stopping, and / or driving the workpiece to rotate alternately in the forward and reverse directions; the method of driving the polishing slurry to rotate at varying speeds includes: driving the polishing slurry to rotate alternately in the forward and reverse directions and / or driving the polishing slurry to rotate at a speed that varies in magnitude.

5. The chemical polishing method according to claim 4, characterized in that, The method of driving the workpiece to rotate at different speeds includes: driving the workpiece to rotate in an alternating manner of rotating for 0.1 seconds to 3 minutes and stopping rotating for 0.1 seconds to 5 seconds; And / or: when the workpiece rotates in an alternating manner of rotation and stopping, the rotation time is 0.5-75 times the stopping time; when the workpiece rotates alternately in the forward and reverse directions, the forward rotation time is 0.5-15.5 times the reverse rotation time.

6. The chemical polishing method according to claim 2, characterized in that, The workpiece is immersed in the polishing liquid in a horizontal direction; and / or the first axis is located in a horizontal direction; and / or the second axis is located in a horizontal direction.

7. The chemical polishing method according to claim 2, characterized in that, The second axis is located outside the area enclosed by the rotation trajectory of the workpiece; And / or the distance from the first axis to the surface of the polishing fluid is less than the distance from the second axis to the surface of the polishing fluid.

8. The chemical polishing method according to claim 2, characterized in that, The number of workpieces is multiple, and the multiple workpieces have the same movement trajectory in the polishing liquid and / or the multiple workpieces are at the same distance from the first axis or the second axis.

9. The chemical polishing method according to claim 2, characterized in that, The step of driving the workpiece to rotate around a first axis in the polishing fluid at a first rotation speed specifically includes: driving the workpiece to revolve / rotate around the first axis in the polishing fluid at the first rotation speed; and / or the step of driving the polishing fluid to rotate at a second rotation speed specifically includes: driving the polishing fluid to rotate / revolve around the second axis at a second rotation speed to stir the polishing fluid and thus drive the polishing fluid to rotate.

10. The chemical polishing method according to claim 1, characterized in that, Immersing the workpiece in the polishing liquid specifically includes: using a workpiece clamp to limit the workpiece in the polishing liquid, and keeping the relative positions of the two ends of the workpiece in the polishing liquid unchanged; The axial direction of the workpiece is the direction of its major axis; the length of the workpiece is 8 to 500 mm; the aspect ratio of the workpiece is 3 to 300.

11. The chemical polishing method according to claim 2, characterized in that, The distance L between the first axis and the second axis, the first rotational speed r1, and the total rotational time t of the workpiece are negatively correlated; and / or the second rotational speed r2 and the total rotational time t of the workpiece are not positively correlated.

12. The chemical polishing method according to claim 1, characterized in that, During the polishing process, there is basically no bubble accumulation in any part of the inner wall and / or the outer wall of the bracket, or the time difference between the bubbles remaining on the workpiece surface is within 10 seconds. The workpiece contacts the polishing liquid in a non-fixed area, and the area of ​​the workpiece in contact with the polishing liquid during the rotation of the workpiece relative to the polishing liquid is not less than 80% of the total surface area of ​​the workpiece.

13. A chemical polishing apparatus, characterized in that, include: A container used to hold polishing liquid; A driving device for driving the polishing fluid to flow relative to the workpiece in a set mode, such that the flow velocity of the polishing fluid relative to the workpiece is substantially consistent along the axial direction of the workpiece.

14. The chemical polishing equipment according to claim 13, characterized in that, The device further includes a workpiece clamp, which includes a polishing fixing device. The polishing fixing device includes a polishing rod or a magnetic fixing device. When the polishing fixing device is a polishing rod, the workpiece is sleeved on the polishing rod along its long axis. When the polishing fixing device is a magnetic fixing device, the workpiece is suspended at the fixed end of the magnetic fixing device.

15. The chemical polishing apparatus according to claim 14, characterized in that, The maximum contact area between the workpiece and the polishing rod is 0.01 to 0.5 times the surface area of ​​the workpiece; the diameter of the polishing rod is smaller than the diameter of the workpiece; the diameter of the polishing rod is 0.3 mm to 18 mm; and the length of the polishing rod is greater than the length of the workpiece.

16. The chemical polishing apparatus according to claim 14, characterized in that, The ratio of the outer diameter of the polishing rod to the inner diameter of the workpiece is (0, 0.92). And / or the distances between each point on the polishing rod and the corresponding positions on the workpiece sleeved thereon are substantially equal; And / or each end of the polishing rod is provided with a limiting member, and the ratio of the length of the polishing rod between the two limiting members to the length of the workpiece is 1.05-1.

5.

17. The chemical polishing apparatus according to claim 14, characterized in that, The driving device causes the contact area between the workpiece and the polishing rod to vary within the range of 0 to the maximum contact area; and / or the driving device includes a first driving device for mounting the workpiece fixture and driving the workpiece to rotate so as to cause the polishing liquid to flow relative to the workpiece.

18. The chemical polishing apparatus according to claim 17, characterized in that, The first driving device includes a clamping shaft, the polishing rod is arranged parallel to and spaced apart from the clamping shaft, and the workpiece rotates around the clamping shaft.

19. The chemical polishing apparatus according to claim 17, characterized in that, The first driving device further includes a first mounting component and a second mounting component, the first mounting component and the second mounting component being fixedly connected to the fixture rotating shaft and arranged opposite to each other at intervals along the fixture rotating shaft, the two ends of the polishing rod being fixed to the first mounting component and the second mounting component respectively; and / or the workpiece fixture includes a plurality of polishing rods arranged in parallel, the plurality of polishing rods being arranged parallel to the fixture rotating shaft at equal or unequal intervals, and each polishing rod being used to mount at least one workpiece.

20. The chemical polishing equipment according to claim 13, characterized in that, The driving device includes a second driving device, which includes a stirring element, wherein the stirring shaft of the stirring element makes an angle of 0 to 10° with the long axis of the workpiece.

21. The chemical polishing equipment according to claim 20, characterized in that, The stirring component further includes at least one fan blade, and the fan blade has one or any combination of the following characteristics: each fan blade is connected to the stirring shaft and extends along the length direction of the stirring shaft; the width of the fan blade is substantially consistent along the axial direction of the stirring shaft; the ratio of the length of the stirring component to the length of the workpiece is greater than or equal to 0.8; the distance between the outer edge of the fan blade and the corresponding position of the workpiece tends to be equal along the axial direction of the workpiece; the distance between the outer edge of the fan blade and the corresponding position of the workpiece is 0.1 to 150 mm.

22. A lumen stent prepared by a chemical polishing method, characterized in that: The lumen support is a tubular body with a hollowed-out pattern, and the cross-sectional profile of the lumen support is a closed smooth curve; the wall thickness removal of the lumen support before and after polishing is 5% to 95%.

23. The lumen stent according to claim 22, characterized in that, The chemical polishing method is the chemical polishing method according to any one of claims 1 to 11; the lumen stent is a biodegradable lumen stent; the lumen stent includes an iron-based stent, a zinc-based stent, or a magnesium-based stent; the substrate of the lumen stent includes pure iron, iron alloy, pure zinc, zinc alloy, pure magnesium, and / or magnesium alloy; the substrate of the lumen stent includes nitrided iron-based.

24. The lumen stent according to claim 22, characterized in that, The length of the lumen stent is 8–500 mm; the aspect ratio of the stent in the expanded state is 2–150; the wall thickness of the stent is 30–500 μm; the rod width of the stent is 45–650 μm; the wall thickness removal after polishing of the lumen stent is [5%, 20%), (20%, 60%), or (60%, 95%); the standard deviation of each dimension of the stent rod after polishing is not greater than 15 μm.

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