Electrochemical polishing device and method for nickel-titanium alloy intracranial stent

Abstract

The present invention discloses an electrochemical polishing device and method for a nickel-titanium alloy intracranial stent, which relates to the technical field related to medical devices. The device comprises a polishing workbench and a lifting platform arranged on the polishing workbench. A clamp is provided on the lifting platform. Driven by the lifting platform, the clamp clamps the stent and enters the polishing liquid on the polishing workbench for electrochemical polishing. The clamp is made of an inert titanium material. The clamp comprises a central rod fixed to the lifting platform, and a plurality of contact rods uniformly arranged circumferentially of the central rod, with a gap between two contact rods at adjacent positions. When the nickel-titanium alloy intracranial stent is electrochemically polished, the stent is sleeved on the outer walls of the plurality of contact rods.

Description

Technical Field

[0001] The present invention relates to the technical field related to medical devices, and in particular to an electrochemical polishing device and method for a nickel-titanium alloy intracranial stent. Background Art

[0002] It is well known that with the development of neurointerventional technology, the application of nickel-titanium alloy stents is becoming more and more extensive. Due to the limitation of the size of intracranial blood vessels, its characteristics are that the stent has a small nominal diameter, low metal coverage, and high surface condition requirements. The small nominal diameter of the stent means a thinner stent rod, and the low metal coverage of the stent means more grid units. The stent is in direct contact with the intracranial blood vessels, which means a brighter and smoother surface treatment. The currently better surface treatment is electrochemical polishing, which can effectively remove burrs, protrusions and other appearance defects.

[0003] The device for electrochemical polishing of nickel-titanium alloy intracranial stents mainly consists of an electrochemical polishing workstation power system, a polishing workbench and an electrochemical polishing temperature control system; Figure 1 As shown in the figure, the working principle of electrochemical polishing of nickel-titanium alloy intracranial stent is as follows:

[0004] Step 1: Pour cooling water 10 into the polishing workbench 1 and add polishing liquid 13 into the beaker 12 containing the pure titanium mesh 11;

[0005] Step 2: Clamp the cathode interface 14 to the edge of the pure titanium mesh 11 to complete the cathode circuit; connect the anode interface 15 to the hanger 2 to complete the anode circuit; turn on the electrochemical polishing power system, set the voltage to a constant 60V, then set the current to 0.2-0.4A, the polishing time to 30-40s, and the number of polishing times to 6-8 times;

[0006] Step 3: Turn on the temperature control system 17 and set the polishing temperature to -5°C to 5°C; wait until the temperature drops to the set temperature;

[0007] Step 4: Use the clamp 3 to clamp the bracket 5, then lock the clamp 3 in the middle of the hanger 2 through the locking nut, control the downward movement of the hanger 2 through the hanger lifting platform 16, and completely immerse the bracket 5 in the polishing liquid 13 (the main components of the polishing liquid are: acetic acid 10%-20%, perchloric acid 5%-10%, glycerin 20%-30%, etc., among which perchloric acid plays the main surface treatment role, and adding an appropriate amount of acetic acid can slow down the polishing speed, and then adding an appropriate amount of glycerin to help brighten the surface of the bracket), until polishing is completed and enter ultrasonic cleaning.

[0008] The shortcoming of the existing technology is that since the bracket has a grid-like structure with narrow rod width and thin wall thickness, if the clamp cannot control the clamping of the bracket well, it is very easy for the bracket to be polished unevenly or the inflection point to be over-polished and broken. Summary of the Invention

[0009] The purpose of the present invention is to provide a nickel-titanium alloy intracranial stent electrochemical polishing device and method to solve the technical problems in the related art.

[0010] In order to achieve the above object, the present invention provides the following technical solutions:

[0011] A nickel-titanium alloy intracranial stent electrochemical polishing device includes a polishing workbench and a lifting platform arranged on the polishing workbench. The lifting platform is provided with a clamp. Driven by the lifting platform, the clamp clamps the stent and enters the polishing liquid on the polishing workbench for electrochemical polishing. The clamp is made of an inert titanium material; the clamp includes a central rod fixed to the lifting platform, and multiple contact rods are evenly arranged circumferentially of the central rod, with a gap between two contact rods at adjacent positions; when the nickel-titanium alloy intracranial stent is electrochemically polished, the stent is sleeved on the outer walls of the multiple contact rods.

[0012] As mentioned above, the number of the contact rods is six, and they are arranged in a hexagonal pattern in the circumferential direction of the central rod.

[0013] As mentioned above, the surface where the contact rod contacts the bracket is in an arc shape.

[0014] As mentioned above, both ends of the six contact rods along the axis of the central rod are tapered.

[0015] As mentioned above, a base block is provided on the center rod along the axial sliding sleeve, and the contact rod is arranged on the base block for radial sliding along the center rod. An extrusion piece is provided on the center rod. When the center rod and the base block move relative to each other in the axial direction, the extrusion piece squeezes the six contact rods based on the power of the center rod to expand along their respective corresponding radial directions.

[0016] As mentioned above, the extrusion part includes six extrusion rods arranged in the circumferential direction of the center rod, and each contact rod is arranged with a first slide, a slider is provided for sliding in the first slide, each slider is connected to the corresponding extrusion rod, and the first slide includes an inclined section and a straight section; in the sliding stroke of the slider from the inclined section in the direction close to the straight section, the contact rod moves in the direction away from the center rod, forming an expansion clamping action on the bracket; in the moving stroke of the slider along the straight section, the six contact rods maintain the expansion clamping action on the bracket; in the sliding stroke of the slider from the straight section in the direction close to the inclined section, the six contact rods move in the direction close to the center rod, and the expansion clamping action on the bracket is removed.

[0017] As mentioned above, the extrusion rod is arranged to slide radially on the center rod, and the sliding direction is consistent with the sliding direction of the corresponding contact rod. In the sliding direction, a first elastic member is provided between the extrusion rod and the center rod. During the sliding stroke of the slider along the inclined section toward the straight section, the elastic force of the first elastic member gradually increases to provide elastic force for the six contact rods to expand outward.

[0018] As mentioned above, the change in the elastic force of the first elastic member includes two strokes: in the first stroke, the elastic force of the first elastic member increases, providing the six contact rods with a force to expand and clamp the bracket, which causes the bracket to undergo elastic deformation; in the second stroke, the elastic force of the first elastic member continues to increase, and the force applied to the contact rod is not sufficient to cause the bracket to continue to undergo elastic deformation.

[0019] As mentioned above, in the axial direction, a second elastic member is provided between the center rod and the base block. When the slider is in the straight section close to the inclined section, the gravity of the six contact rods is balanced by the elastic force of the second elastic member, and the six contact rods and the center rod remain in a relatively static state; when the slider is in the straight section away from the inclined section, under the action of the rebound force of the second elastic member, the six contact rods overcome the action of gravity and move upward.

[0020] The present invention also relates to a method for chemical polishing of a nickel-titanium alloy intracranial stent, wherein the method comprises the following steps when the nickel-titanium alloy intracranial stent is polished by the nickel-titanium alloy intracranial stent electrochemical polishing device described above:

[0021] Step 1: Clamp the bracket. Fix the center rod on the lifting platform, then sleeve the bracket onto the six contact rods. Push the six contact rods along the axis of the center rod to move each slider along the corresponding inclined section into the straight section. The six contact rods expand radially away from the center rod to clamp the bracket.

[0022] Step 2: Polishing of the bracket: The lifting platform drives the bracket through the clamp into the polishing liquid on the polishing workbench for electrochemical polishing.

[0023] The beneficial effects of the present invention are that the clamp is made of inert titanium material, which has good electrical conductivity and corrosion resistance, does not participate in ionic chemical reactions, and multiple contact rods are in multi-angle contact with the bracket. There is a gap between two adjacent contact rods, that is, multiple contact rods are hollowed out with the center rod to ensure that the bracket is clamped without falling off. Compared with the traditional point clamping method, it solves the pain points of over-polishing or pitting at the clamping points of the bracket, and at the same time makes the polishing of various parts of the bracket more even, avoiding the generation of thick and thin rods in the bracket. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments described in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0025] Figure 1 A schematic plan view of the electrochemical polishing device for a nickel-titanium alloy intracranial stent according to an embodiment of the present invention;

[0026] Figure 2 A schematic diagram of the three-dimensional structure of a fixture of an electrochemical polishing device for a nickel-titanium alloy intracranial stent according to an embodiment of the present invention;

[0027] Figure 3 A schematic diagram of the radial cross-sectional structure of a fixture of an electrochemical polishing device for a nickel-titanium alloy intracranial stent according to an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of the axial cross-sectional structure of a fixture portion of an electrochemical polishing device for a nickel-titanium alloy intracranial stent according to an embodiment of the present invention;

[0029] Figure 5 A schematic diagram of the axial cross-sectional structure of another part of a fixture of an electrochemical polishing device for a nickel-titanium alloy intracranial stent according to an embodiment of the present invention;

[0030] Figure 6 for Figure 5 A in the figure shows the enlarged structural diagram;

[0031] Figure 7 This is a schematic diagram of the axial cross-sectional structure of a nickel-titanium alloy intracranial stent electrochemical polishing device according to an embodiment of the present invention when the slider is in a straight line segment;

[0032] Figure 8 for Figure 7 A schematic diagram of the structure at point B in FIG.

[0033] Figure 9 A schematic diagram showing a planar structure of a comparison of a first slideway and a second slideway on two adjacent contact rods of an electrochemical polishing device for a nickel-titanium alloy intracranial stent according to an embodiment of the present invention;

[0034] Figure 10 This is a schematic diagram of the comparative planar structure of the second slideways on two adjacent contact rods of an electrochemical polishing device for a nickel-titanium alloy intracranial stent in an embodiment of the present invention.

[0035] Description of reference numerals:

[0036] 1. Polishing workbench; 10. Cooling water; 11. Pure titanium mesh; 12. Beaker; 13. Polishing liquid; 14. Cathode interface; 15. Anode interface; 16. Lifting platform; 17. Temperature control system; 2. Hanger; 3. Clamp; 30. Center rod; 31. Contact rod; 32. Base block; 33. Slide; 34. Extrusion rod; 35. First slide; 350. Inclined section; 351. Straight section; 36. Slider; 37. Second slide; 38. Locking rod; 39. Trigger block; 40. Unlocking rod; 41. Transition section; 5. Bracket. DETAILED DESCRIPTION

[0037] In order to make those skilled in the art better understand the technical solution of the present invention, Figure 1 To the attached Figure 10 The present invention is further described in detail.

[0038] An embodiment provided by the present invention relates to an electrochemical polishing device for a nickel-titanium alloy intracranial stent 5, comprising a polishing workbench 1 and a lifting platform 16 arranged on the polishing workbench 1, wherein the lifting platform 16 is provided with a clamp 3. Driven by the lifting platform 16, the clamp 3 clamps the stent 5 and enters the polishing liquid 13 on the polishing workbench 1 for electrochemical polishing treatment, wherein the clamp 3 is made of an inert titanium material; the clamp 3 includes a central rod 30 fixed to the lifting platform 16, and a plurality of contact rods 31 uniformly arranged circumferentially of the central rod 30, with a gap between two contact rods 31 at adjacent positions; when the nickel-titanium alloy intracranial stent 5 is electrochemically polished, the stent 5 is sleeved on the outer wall of the plurality of contact rods 31.

[0039] Specifically, the device for electrochemical polishing the nickel-titanium alloy intracranial stent 5 is mainly composed of an electrochemical polishing workstation power system, a polishing workbench 1 and an electrochemical polishing temperature control system. The overall production process of the stent 5 is: nickel-titanium tube cutting - cutting waste cleaning - ultrasonic cleaning - stent 5 preheating treatment - stent 5 shaping - stent 5 polishing; the polishing principle of the stent 5 is introduced in detail in the background technology, and will not be elaborated on here. The lifting platform 16 can be a screw transmission mechanism, which is a prior art and will not be elaborated on. The connection between the lifting platform 16 and the clamp 3 can be fixed by bolts. The lifting platform 16 drives the bracket 5 to move vertically through the clamp 3, that is, drives the bracket 5 in and out of the polishing liquid 13 vertically. In the prior art, since the bracket 5 has a grid structure with the characteristics of thin rod width and thin wall thickness, if the clamp 3 cannot control the clamping of the bracket 5 well, it is very easy for the bracket 5 to be unevenly polished or over-thrown and broken at the inflection point.

[0040] Therefore, in this embodiment, the clamp 3 is made into a structure supported from the inner wall of the bracket 5, that is, the clamp 3 is composed of a center rod 30 and a plurality of contact rods 31 arranged circumferentially on the outer wall of the center rod 30. The center rod 30 is a long cylindrical structure, and the radial cross-section of the contact rod 31 is a fan-shaped structure. The contact rod 31 is away from the side of the center rod 30, that is, the outer wall of the contact rod 31 contacts and clamps the inner wall of the support, and the adjacent two contact rods 31 are arranged at intervals, that is, the clamp 3 is a hollow structure as a whole, and the clamp 3 as a whole adopts an inertial structure. The advantage of such a design is that the clamp 3 is made of inert titanium material, which has good electrical conductivity and good corrosion resistance and does not participate in ionic chemical reactions. Multiple contact rods 31 are in multi-angle contact with the bracket 5, and there is a gap between two adjacent contact rods 31, that is, multiple contact rods 31 are hollowed out with the center rod 30 to ensure that the bracket 5 is clamped without falling off. Compared with the traditional point clamping method, it solves the pain point of over-polishing or pitting of the clamping point of the bracket 5, and at the same time makes the polishing of various parts of the bracket 5 more uniform, avoiding the generation of thick and thin rods of the bracket 5.

[0041] Preferably, the number of the contact rods 31 is six, and they are arranged in a hexagonal pattern in the circumferential direction of the center rod 30; specifically, the six contact rods 31 are arranged in a hexagonal pattern in the circumferential direction, which ensures sufficient contact area with the bracket 5 while also ensuring that the gap between two adjacent contact rods 31 does not affect the electrochemical polishing operation of the bracket 5.

[0042] Preferably, the surface of the contact rod 31 in contact with the bracket 5 is arc-shaped; specifically, the outer wall of the contact rod 31 is arc-shaped, and when it contacts the inner wall of the bracket 5, it will not produce a bending indentation on the bracket 5, so as to ensure that the bracket 5 can be used normally.

[0043] Preferably, both ends of the six contact rods 31 along the axial direction of the central rod 30 are tapered structures; specifically, the tapered structure facilitates the bracket 5 to be quickly sleeved on the outer walls of the six contact rods 31 .

[0044] Furthermore, a base block 32 is provided on the center rod 30 along an axial sliding sleeve, and the contact rods 31 are arranged on the base block 32 to slide radially along the center rod 30. An extrusion piece is provided on the center rod 30. When the center rod 30 and the base block 32 move relative to each other in the axial direction, the extrusion piece squeezes the six contact rods 31 based on the power of the center rod 30 to expand along their respective corresponding radial directions.

[0045] Specifically, in the aforementioned embodiment, the bracket 5 is directly sleeved on the outer walls of the six contact rods 31 during electrochemical polishing, and the friction between it and the outer walls of the contact rods 31 is used to ensure that it will not fall off during polishing. However, this friction force will hinder the bracket 5 from being sleeved on the six contact rods 31, and will also hinder the bracket 5 from being removed from the six contact rods 31 after polishing is completed.

[0046] Therefore, in this embodiment, the six contact rods 31 are set to a movable structure, and the six contact rods 31 are all arranged to slide along their corresponding radial directions on the base block 32, that is, a sliding groove 33 corresponding to each contact rod 31 is arranged on the circumference of the base block 32, and a part of each contact rod 31 is arranged to slide in the corresponding sliding groove 33, and then when the axial relative movement occurs between the central rod 30 and the base block 32, the extrusion piece is used to control the expansion and contraction of the six contact rods 31, so that the bracket 5 can be taken and placed.

[0047] In a preferred embodiment, the extrusion member includes six extrusion rods 34 arranged in the circumferential direction of the central rod 30, and each contact rod 31 is provided with a first slide 35. A slider 36 is provided in the first slide 35. The slider 36 can only slide along its track in the first slide 35, and the slider 36 cannot be separated from the first slide 35 in other directions. The depth direction of the first slide 35 is consistent with the sliding direction of the corresponding contact rod 31 on the base block 32. Each slider 36 is connected to the corresponding extrusion rod 34, and the first slide 35 includes an inclined section 350 and a straight section 351. The depth of the straight section 351 is kept constant on its track. The depth of the end of the inclined section 350 away from the straight section 351 is greater than that of the end close to the straight section 351; during the sliding stroke of the slider 36 from the inclined section 350 to the direction close to the straight section 351, the contact rod 31 moves in the direction away from the center rod 30, forming an expansion clamping action on the bracket 5; during the moving stroke of the slider 36 along the straight section 351, the six contact rods 31 maintain the expansion clamping action on the bracket 5; during the sliding stroke of the slider 36 from the straight section 351 to the direction close to the inclined section 350, the six contact rods 31 move in the direction close to the center rod 30, and the expansion clamping action on the bracket 5 is removed.

[0048] Before operation, the six contact rods 31 are attached to the center rod 30 along their respective radial directions. During operation, the bracket 5 is first placed on the outer walls of the six contact rods 31. At this time, the bracket 5 has not yet contacted the outer walls of the six contact rods 31. Then, the six contact rods 31 are pushed to move relative to the center rod 30. That is, when the six contact rods 31 are used as a reference, the center rod 30 extends from the middle of the six contact rods 31. The movement of the center rod 30 drives the six extrusion rods 34 to move together. Then, each extrusion rod 34 drives its corresponding connected slider 36 to move along the inclined section 350 toward the straight section 351. In this embodiment, the length of the extrusion rod 34 cannot be extended or shortened, so the extrusion rod 34 and the inclined section 350 are wedge-shaped to form an extrusion action, so that each contact rod 31 moves toward the far end along its respective radial direction. Move in the direction away from the center rod 30, that is, the six contact rods 31 expand outward at the same time to internally support and clamp the bracket 5. After the slider 36 enters the straight section 351, there is no wedge-shaped matching structure between the extrusion rod 34 and the straight section 351, and no extrusion action can be formed. In this way, the six contact rods 31 maintain a stable internal support and clamping of the bracket 5. On the contrary, the slider 36 enters the inclined section 350 from the straight section 351, and the wedge-shaped matching between the extrusion rod 34 and the corresponding inclined section 350 no longer performs an extrusion action. Instead, the extrusion rod 34 cooperates with the slider 36 to form a pulling action on the contact rod 31, so that the contact rod 31 approaches the center rod 30 radially. In this way, the six contact rods 31 will remove the internal support and clamping of the bracket 5, thereby facilitating the removal of the bracket 5 after polishing, and at the same time, internal support and clamping can be performed on brackets 5 of different radial sizes.

[0049] In an optional embodiment, the extrusion rod 34 is arranged to slide radially on the center rod 30, and the sliding direction is consistent with the sliding direction of the corresponding contact rod 31. In the sliding direction, a first elastic member is provided between the extrusion rod 34 and the center rod 30. During the sliding stroke of the slider 36 along the inclined section 350 toward the straight section 351, the elastic force of the first elastic member gradually increases to provide an elastic force for the six contact rods 31 to expand outward.

[0050] Specifically, in the aforementioned embodiment, the internal support clamping of the bracket 5 is achieved by the expansion of the six contact rods 31. When the extrusion rod 34 drives the slider 36 to slide along the inclined section 350 toward the direction close to the straight section 351, as the distance between the slider 36 and the straight section 351 becomes closer and closer, the extrusion force exerted by the extrusion rod 34 on the contact rod 31 becomes greater and greater, and the internal support force of the contact rod 31 on the bracket 5 is also gradually increasing. If the strength of the internal support clamping cannot be properly controlled, there is a risk of the internal support damaging the bracket 5. In order to maintain the six contact rods 31 on the bracket 5 is clamped stably, the slider 36 must reach the straight section 351. Therefore, in order to avoid damaging the bracket 5, in this embodiment, the extrusion rod 34 is arranged on the center rod 30 along the radial sliding direction, and the sliding direction is consistent with the sliding direction of its corresponding contact rod 31, and each extrusion rod 34 is provided with a first elastic member between it and the center rod 30 in the sliding direction. The elastic force of the first elastic member is utilized to generate a flexible extrusion force between the extrusion rod 34 and the contact rod 31, thereby providing a certain protection to the bracket 5 when the bracket 5 is clamped by the internal support.

[0051] In another optional embodiment, the elastic force change of the first elastic member includes two strokes: in the first stroke, the elastic force of the first elastic member increases, providing the six contact rods 31 with a force to expand and clamp the bracket 5, which causes the bracket 5 to undergo elastic deformation; in the second stroke, the elastic force of the first elastic member continues to increase, and the force applied to the contact rods 31 is not sufficient to cause the bracket 5 to continue to undergo elastic deformation.

[0052] Specifically, in the aforementioned embodiment, the elastic force of the first elastic member is used to generate a flexible squeezing force between the squeezing rod 34 and the contact rod 31, thereby providing a certain protection to the bracket 5 when the bracket 5 is internally supported and clamped. However, as the elastic force of the first elastic member gradually increases, the contact rod 31 also has a greater internal supporting effect on the bracket 5, and there is a certain probability that the bracket 5 will be damaged. Therefore, in this embodiment, the elastic force of the first elastic member should first provide sufficient force for the six contact rods 31 to internally support and clamp the bracket 5 during the increasing process. At this time, the elastic force of the first elastic member makes the positive pressure between the contact rod 31 and the bracket 5 just enough to maintain the bracket 5 from being damaged. The contact rod 31 moves axially (corresponding to the first stroke). In the process of the elastic force of the first elastic member increasing, the six contact rods 31 can continue to expand outward until the slider 36 enters the straight section 351. The expansion of the six contact rods 31 can cause the bracket 5 to produce a certain elastic deformation, but the elastic deformation is within its normal elastic change range. For example, the elastic deformation of the bracket 5 is 1, and the maximum deformation of the first elastic member is 0.9, that is, the maximum elastic force generated by the first elastic member is insufficient to cause the bracket 5 to continue to deform elastically after the elastic deformation reaches 1 (corresponding to the second stroke). In this way, the bracket 5 can be protected during the process of being clamped by the internal support.

[0053] Furthermore, in the axial direction, a second elastic member is provided between the center rod 30 and the base block 32. When the slider 36 is in the straight section 351 close to one end of the inclined section 350, the gravity of the six contact rods 31 is balanced with the elastic force of the second elastic member, and the six contact rods 31 and the center rod 30 remain in a relatively static state; when the slider 36 is in the straight section 351 away from one end of the inclined section 350, under the action of the rebound force of the second elastic member, the six contact rods 31 overcome the action of gravity and move upward.

[0054] Specifically, during the electrochemical polishing process of the bracket 5, the movement of the bracket 5 can have a certain impact on the polishing effect: first, the movement of the bracket 5 can help achieve a uniform distribution of the polishing liquid 13, so as to improve the uniformity of polishing and reduce the risk of local over-polishing or pitting; second, the movement of the bracket 5 can help remove bubbles generated during the polishing process and ensure that the polishing liquid 13 is in good contact with the surface of the bracket 5; third, the appropriate movement of the bracket 5 can increase the uniformity of the current density, thereby improving the polishing efficiency; the movement of the bracket 5 can be rotation, vibration or linear motion. When performing linear motion, the speed needs to be adjusted according to the characteristics of the polishing liquid 13 and the material. Too fast may lead to uneven polishing, and too slow may reduce the drop. Therefore, in this embodiment, a second elastic member is set between the center rod 30 and the base block 32. In order to ensure that the six contact rods 31 can stably clamp the bracket 5, the slider When 36 is in the straight section 351 close to one end of the inclined section 350, the gravity of the six contact rods 31 is balanced by the elastic force of the second elastic member, and the six contact rods 31 and the center rod 30 remain in a relatively static state. At this time, when the bracket 5 is polished, the bracket 5 will not move linearly in the polishing liquid 13. When the slider 36 moves to the other end in the direction away from the inclined section 350 in the straight section 351, if there is no external force continuing to act on the six contact rods 31 and the center rod 30 to move relative to each other, the rebound force of the second elastic member is greater than the gravity of the six contact rods 31. Then, under the action of the rebound force of the second elastic member, the six contact rods 31 move axially, driving the bracket 5 to move linearly in the polishing liquid 13. The moving speed of the six contact rods 31 can be adjusted according to the actual situation, its gravity and the manufacturing specifications of the second elastic member to ensure the uniformity of the polishing of the bracket 5 while ensuring the polishing efficiency.

[0055] In another embodiment provided by the present invention, a second slideway 37 is further provided on each contact rod 31, one end of the second slideway 37 is connected to the inclined section 350, and the other end is connected to the straight section 351, the second slideway 37 is wavy, and in the radial direction of the center rod 30, the trough of the second slideway 37 is farther away from the center rod 30 than the crest. In this way, when the slider 36 is at the crest position, the corresponding contact rod 31 contacts the inner wall of the bracket 5, and when the slider 36 is at the trough position, the contact rod 31 contracts inwardly close to the center rod 30 and no longer contacts the inner wall of the bracket 5. In this way, the six contact rods 31 are evenly divided into two groups, and the three contact rods 31 in each group are arranged at intervals in the circumferential direction with the three contact rods 31 in the other group. Then, the crest positions and trough positions of the two second slideways 37 on the two contact rods 31 at adjacent positions should be staggered. For the convenience of description, the six contact rods 31 are named J1, J2, J3, J4, J5, and J6 in the clockwise direction, that is, J1, J3 and J5 are a group, and the arrangement of the three second slideways 37 is consistent. J2, J4 and J6 are a group, and the arrangement of the three second slideways 37 is consistent. The crest of J1 corresponds to the trough of J2, and the crest of J2 corresponds to the trough of J1. When J1, J3 and J5 are about to break away from the internal support clamping of the bracket 5, J2, J4 and J6 need to internally support and clamp the bracket 5, that is, the crest of J1 should partially overlap with the crest of J2, and the crest of J2 should partially overlap with the crest of J1. 3 partially overlaps, and so on, the wave crests of J6 and J1 also partially overlap, so that after the slider 36 enters the second slide 37 from the straight section 351, the six contact rods 31 drive the bracket 5 to move linearly based on the rebound of the second elastic member, and the two groups of contact rods 31 can alternately support and clamp the bracket 5, so that all parts of the inner wall of the bracket 5 can be in contact with the polishing liquid 13, thereby ensuring the comprehensiveness and uniformity of the polishing of the inner wall of the bracket 5.

[0056] In the above, during the movement of the slider 36 in the second slide 37, the length of the extrusion rod 34 should not change, so that the second slide 37 can be coordinated to realize the two contact rods 31 to alternately support and clamp the bracket 5, that is, a locking structure is provided at the connection between each extrusion rod 34 and the center rod 30, and the locking structure includes two locking rods 38 symmetrically arranged in the sliding space of each extrusion rod 34, and the locking rods 38 are swingably arranged on the center rod 30. A trigger block 39 is provided between the swing axes of the two locking rods 38 and slides along the sliding direction of the extrusion rod 34. The trigger block 39 is in friction contact with the two locking rods 38, and a third elastic member is provided between the trigger block 39 and the center rod 30 in the sliding direction. The ends of the two locking rods 38 away from their respective swing axes tend to approach each other due to the elastic force of the third elastic member. When the slider 36 is in the straight section 351, the ends of the two locking rods 38 away from their respective swing axes cannot approach each other due to the restriction of the extrusion rod 34. When the slider 36 reaches the straight section 351, the extrusion rod 34 restricts the contact of the locking rod 38. Then, under the elastic force of the third elastic member, the ends of the two locking rods 38 away from their respective swing axes approach each other to lock the extrusion rod 34. That is, the extrusion rod 34 has a T-shaped structure. When the slider 36 is in the straight section 351, it is away from the extrusion rod 34. One end of the slider 36 is restricted by the two locking rods 38 in its sliding direction, so that the extrusion rod 34 cannot move away from the center rod 30 in the sliding direction under the action of the rebound force of the first elastic member, thereby achieving the locking of the extrusion rod 34. After the polishing of the bracket 5 is completed, when the bracket 5 needs to be removed from the six contact rods 31, the extrusion rod 34 is required to drive the slider 36 into the inclined section 350. In this way, the lock of the extrusion rod 34 needs to be contacted, that is, an unlocking rod 40 is provided inside the center rod 30 along the axial sliding. The unlocking rod 40 is close to the end of the bracket 5 when the slider 36 enters the straight section 351 from the inclined section 350. In the process of entering the second slideway 37 from the straight section 351, it always rests against the center rod 30. When the squeezing rod 34 needs to be unlocked, the unlocking rod 40 is pushed in the direction away from the bracket 5. The unlocking rod 40 and each trigger block 39 are wedge-shaped to form an squeezing action. The movement of the trigger block 39 causes the corresponding two locking rods 38 to swing relative to each other, that is, the two locking rods 38 are away from each other at one end of the swing axis to contact and lock the squeezing rod 34. In this way, the squeezing rod 34 drives the slider 36 so that the second slide 37 enters the inclined section 350. During this process, the six contact rods 31 can retract inward to remove the inner support clamping of the bracket 5, wherein a transition section 41 is provided between the second slide 37 and the inclined section 350, and the inclination angle of the transition section 41 is consistent with the inclination angle of the inclined section 350.

[0057] Another embodiment provided by the present invention relates to a chemical polishing method for a nickel-titanium alloy intracranial stent 5, wherein the method comprises the following steps when the nickel-titanium alloy intracranial stent 5 is polished by the above-mentioned nickel-titanium alloy intracranial stent 5 electrochemical polishing device:

[0058] Step 1: Clamping the bracket 5. Fix the center rod 30 on the lifting platform 16. Then, sleeve the bracket 5 onto the six contact rods 31. Push the six contact rods 31 axially along the center rod 30 to move each slider 36 along the corresponding inclined section 350 into the straight section 351. The six contact rods 31 expand radially away from the center rod 30 to clamp the bracket 5.

[0059] Step 2: Polishing of the bracket 5: The lifting platform 16 drives the bracket 5 through the clamp 3 into the polishing liquid 13 on the polishing workbench 1 for electrochemical polishing.

[0060] The above description is merely illustrative of certain exemplary embodiments of the present invention. It goes without saying that those skilled in the art will be able to modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and description are illustrative in nature and should not be construed as limiting the scope of protection of the claims.

Claims

1. A nickel-titanium alloy intracranial stent electrochemical polishing device, comprising a polishing table and a lifting platform provided on the polishing table, wherein a clamp is provided on the lifting platform. Driven by the lifting platform, the clamp clamps the stent into the polishing liquid on the polishing table for electrochemical polishing, characterized in that: The fixture is made of an inert titanium material; The fixture includes a central rod fixed to the lifting platform, and a plurality of contact rods evenly arranged around the central rod, with a gap between two adjacent contact rods; when electrochemically polishing the nickel-titanium alloy intracranial stent, the stent is sleeved on the outer walls of the plurality of contact rods; The number of the contact rods is six and they are arranged in a hexagonal pattern in the circumferential direction of the central rod; A base block is provided on the center rod along the axial sliding sleeve, and the contact rods are arranged on the base block for radial sliding along the center rod. An extrusion piece is provided on the center rod. When the center rod and the base block move relative to each other in the axial direction, the extrusion piece squeezes the six contact rods to expand along their respective corresponding radial directions based on the power of the center rod.

2. The electrochemical polishing device for nickel-titanium alloy intracranial stent according to claim 1, characterized in that: The surface of the contact rod in contact with the bracket is in an arc shape.

3. The electrochemical polishing device for nickel-titanium alloy intracranial stent according to claim 1, characterized in that: Both ends of the six contact rods along the axis of the central rod are tapered structures.

4. The electrochemical polishing device for nickel-titanium alloy intracranial stent according to claim 1, characterized in that: The extrusion member includes six extrusion rods arranged in the circumferential direction of the central rod, each contact rod is provided with a first slideway, a slider is provided in the first slideway, each slider is connected to the corresponding extrusion rod, and the first slideway includes an inclined section and a straight section; When the slider slides from the inclined section to the direction close to the straight section, the contact rod moves in the direction away from the center rod, thereby forming an expansion and clamping action on the bracket; As the slider moves along the straight line, the six contact rods maintain the expansion and clamping action on the bracket; During the sliding stroke of the slider from the straight section to the direction close to the inclined section, the six contact rods move in the direction close to the central rod, and the expansion clamping action on the bracket is removed.

5. The electrochemical polishing device for nickel-titanium alloy intracranial stent according to claim 4, characterized in that: The extrusion rod is arranged to slide radially on the center rod, and the sliding direction is consistent with the sliding direction of the corresponding contact rod. In the sliding direction, a first elastic member is provided between the extrusion rod and the center rod. During the sliding stroke of the slider along the inclined section to the straight section, the elastic force of the first elastic member gradually increases to provide elastic force for the six contact rods to expand outward.

6. The electrochemical polishing device for nickel-titanium alloy intracranial stent according to claim 5, characterized in that: The elastic force change of the first elastic member includes two strokes: in the first stroke, the elastic force of the first elastic member increases, providing the six contact rods with a force to expand and clamp the bracket, which causes the bracket to undergo elastic deformation; in the second stroke, the elastic force of the first elastic member continues to increase, and the force applied to the contact rod is not sufficient to cause the bracket to continue to undergo elastic deformation.

7. The electrochemical polishing device for nickel-titanium alloy intracranial stent according to claim 4, characterized in that: In the axial direction, a second elastic member is provided between the center rod and the base block. When the slider is in the straight section close to the inclined section, the gravity of the six contact rods is balanced by the elastic force of the second elastic member, and the six contact rods and the center rod remain in a relatively static state; when the slider is in the straight section away from the inclined section, under the action of the rebound force of the second elastic member, the six contact rods overcome the action of gravity and move upward.

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