Manufacturing method of left atrial appendage occluder framework by high-speed electric spark milling

Abstract

A kind of left auricle occluder framework high-speed electric spark milling processing manufacturing method.First, the shell with the initial form of left auricle occluder framework is prepared by base, upper casting mold, middle casting mold and lower casting mold casting, then the hole for fixing is processed to the shell by drill bit, and then the excess material on the shell is removed by high-speed electric spark discharge milling through the method of high-speed electric spark milling processing on multi-axis linkage electric spark machine tool, the mesh framework semi-finished product with the shell of the part to be processed barb is processed, and the barb is processed using the same high-speed electric spark milling processing method, and the heat treatment memory shaping is carried out through product shaping upper mold, product shaping middle mold, product shaping lower mold and base etc.Finally, the manufacturing is completed after cleaning.The high-speed electric spark milling processing manufacturing method improves the precision, surface quality and consistency of the occluder framework processing, does not need to process special electrode, improves the processing efficiency, reduces the processing cost, solves the problem that left auricle occluder framework cannot be integrally formed and manufactured, and can realize the individual customization of left auricle occluder framework in any form.

Description

Technical Field

[0001] This invention relates to the processing and manufacturing of a cardiac medical device, specifically to a method for manufacturing a left atrial appendage occluder skeleton using high-speed electrical discharge milling. Background Technology

[0002] The clinical application of left atrial appendage occlusion (LAA) technology has developed rapidly. In terms of specialized medical devices, there are currently two main types globally, namely internal plug and external cap occluders, with more than ten different models used clinically. Among these, some researchers have proposed internal plug LAA occluders primarily composed of a metal skeleton and a mesh-like biodegradable membrane. The skeleton of the LAA occluder is crucial for its occlusion effect after release; the metal skeleton and its barbs ensure fixation and support after insertion into the left atrial appendage.

[0003] The skeleton of an internal left atrial appendage occluder often has a complex curved shape to meet the requirements of repeated contraction and release, and provides good occlusion when released at the left atrial appendage. Currently, traditional manufacturing methods mainly involve separate manufacturing followed by threaded connections, welding, and gluing. Some researchers have also woven various barbed filaments from raw materials into the skeleton. While separate manufacturing and assembly makes it easier to achieve dimensional and shape accuracy for individual skeletons, welding and gluing reduce the skeleton's fatigue resistance and make it prone to cracking and failure at the joints. Screw connections result in excessively small parts on the skeleton, making manufacturing and assembly difficult and posing potential risks to patients during subsequent use. Weaving filaments allows for better control of the skeleton's mesh density, but the weaving process and overall fabrication are complex. The various filaments used in the weaving process require precise length calculations before weaving, making it difficult to meet the demand for customized sizes.

[0004] Shanghai Shenqi Medical Technology Co., Ltd. disclosed a left atrial appendage occluder skeleton in CN104905840B, including a central ring frame with proximal and distal conical frames at both ends, the apexes of which are located inside the central ring frame. The beneficial effects of this invention are: 1) The fixing cap of the proximal conical frame does not protrude, thus not affecting blood flow and reducing the risk of secondary thrombosis; 2) The distal conical frame adopts a closed-loop design, with uniform expansion and compression deformation, resulting in a "flower" shape in the initial release form of the left atrial appendage occluder skeleton rather than a sharp "stick" shape, avoiding damage to the inner wall of the left atrial appendage during release; the central ring frame adopts a closed-loop design, ensuring that the axial length of the left atrial appendage occluder skeleton remains unchanged or changes very little during expansion or compression, adapting to left atrial appendages of various depths; 3) The overall structural design provides the left atrial appendage occluder skeleton with sufficient support and flexibility. A left atrial appendage occluder skeleton is made of nickel-titanium alloy, cobalt-based alloy, or other superelastic alloy. The entire skeleton is laser-cut and then heat-treated to form the desired columnar shape (i.e., a metal tube is hollowed out using laser cutting according to design requirements, and then heat-treated to process the hollowed-out metal tube into a columnar shape). From the above processing method, it is clear that the wave rod is a metal wire. However, specific implementation steps are not provided, and those skilled in the art cannot know the specific manufacturing process, making actual manufacturing impossible. Summary of the Invention

[0005] To address the aforementioned shortcomings of existing technologies, this invention proposes a high-speed electrical discharge milling method for manufacturing a left atrial appendage occluder skeleton. First, a shell with the initial shape of the left atrial appendage occluder skeleton is prepared by casting a base, an upper casting mold, a middle casting mold, and a lower casting mold. Then, holes for fixing are machined into the shell using a drill bit. Next, excess material on the shell is removed by high-speed electrical discharge milling on a multi-axis EDM machine, producing a mesh-like skeleton semi-finished product with barbs to be machined. The barbs are then machined using the same high-speed electrical discharge milling method. The product is then heat-treated and shaped using an upper mold for product shaping, a middle mold for product shaping, a lower mold for product shaping, and the base. Finally, the product is cleaned to complete the manufacturing process. This invention improves the precision, surface quality, and consistency of the occluder skeleton through high-speed electrical discharge milling, eliminating the need for specialized electrodes, thus increasing processing efficiency and reducing costs. It also solves the problem of the inability to manufacture the left atrial appendage occluder skeleton in a single piece, enabling personalized customization of any shape for the left atrial appendage occluder skeleton. This invention is achieved through the following technical solution:

[0006] This invention relates to a method for manufacturing a left atrial appendage occluder skeleton using high-speed electrical discharge milling, specifically achieved through the following steps:

[0007] S1: Design the base shape and shell based on the finished hooked mesh skeleton;

[0008] S2: Design casting molds and finished product shaping molds based on the base material, shell, and hooked mesh skeleton;

[0009] S3: After installing magnetic positioning pins and filler on the substrate, assemble the casting mold;

[0010] S4: After molten material is injected into a casting mold, it is cast to form shell A;

[0011] S5: Demold shell A, install the fastening cover together with the base body, and install the mounting adapter plate to assemble it into a tooling;

[0012] S6: Use a drill bit to drill a hole in housing A to obtain housing B. After removing the filler material from the base, install the fastening screws.

[0013] S7: Experimentally obtain the electrode wear rate of high-speed EDM milling under the corresponding working conditions and calculate the wear compensation value;

[0014] S8: Calculate and generate the toolpath trajectory for high-speed EDM machining of the skeleton using CAM software, confirm and generate machining code;

[0015] S9: Remove excess material from shell B by high-speed electrical discharge milling to create a mesh skeleton semi-finished product;

[0016] S10: The barbs on the semi-finished mesh skeleton are machined by high-speed electrical discharge milling to form a hooked mesh skeleton;

[0017] S11: The hooked mesh skeleton is heat-treated and shaped using the finished product shaping upper mold, finished product shaping middle mold, finished product shaping lower mold and base, etc., to produce the finished hooked mesh skeleton;

[0018] S12: Clean and remove dirt from the finished hooked mesh skeleton.

[0019] In one embodiment, the left atrial appendage occluder skeleton is an open-type skeleton.

[0020] In one embodiment, the left atrial appendage occluder skeleton is made of nickel-titanium shape memory alloy.

[0021] In one embodiment, the filler material has high temperature resistance and is not affected during the casting stage but can be easily removed after casting is completed, such as clay sand, quartz sand, limestone sand, etc., but not limited to the above materials.

[0022] In one embodiment, the substrate material is a non-conductive ceramic, but is not limited to non-conductive ceramics. It also includes various non-conductive substrates that meet the requirements, such as various metals and non-metals with a non-conductive coating on the surface.

[0023] In one embodiment, the mold for heat treatment memory shaping has channels and gaps for hot air circulation.

[0024] In one embodiment, the electrode used in high-speed electrical discharge milling is a hollow cylindrical electrode.

[0025] In one embodiment, the electrode wire material used in high-speed electrical discharge milling is a conductive material, typically brass, copper, titanium alloy, etc., and the polarity of high-speed electrical discharge milling is positive.

[0026] In one embodiment, the working fluid is deionized water to ensure the cleanliness of the workpiece surface after processing.

[0027] In one embodiment, the high-speed electrical discharge milling edge-to-edge function uses a voltage short-circuit signal to determine contact.

[0028] In one embodiment, high-speed electrical discharge milling uses the discharge signal and its statistical information collected between electrodes as the basis for servo control and loss compensation, thereby ensuring the complete removal of material from the machined area on the housing.

[0029] In one embodiment, high-pressure flushing fluid is introduced into the electrode wire of the high-speed electrical discharge milling process to quickly remove chips.

[0030] Compared with existing technologies, this invention comprehensively solves the problem that it is difficult to achieve integral molding of the left atrial appendage occluder skeleton and barbs, and also solves the problem of complex process design when customizing left atrial appendage occluder skeletons of various shapes. This invention obtains a shell with the shape of a left atrial appendage occluder skeleton through precision casting, avoiding the need for precise estimation of raw materials and improving the accuracy of the blank. After casting, the shell is fixed to the base body using fastening screws and fastening caps. The shell and base body do not separate during the entire manufacturing process, thereby reducing the probability of deformation or movement of the shell during processing and ensuring processing accuracy. Material is removed through a non-contact machining method using multi-axis linkage high-speed EDM milling. The skeleton and barbs are processed sequentially under the same equipment and tooling, improving processing efficiency and accuracy. This avoids the problem of easy cracking and breakage failure of the skeleton parts due to pre-bending the barbs and then connecting them using various methods, which is common in traditional methods. The unique new functions / effects of this invention include: reverse designing the substrate, casting mold, shaping mold, and generating high-speed EDM machining trajectory through the design model of the left atrial appendage occluder skeleton, ensuring subsequent machining accuracy; obtaining a shell with the shape of the left atrial appendage occluder skeleton through precision casting, avoiding precise estimation of raw materials and improving blank accuracy; using fastening screws and fastening caps to fix the shell and substrate throughout the entire machining process, reducing machining errors; using a non-contact machining method of high-speed EDM to remove material, and machining the skeleton and barbs sequentially under the same equipment and tooling to precisely control the shape of the finished left atrial appendage occluder skeleton and ensure product quality; compared with other methods, the method proposed in this invention can achieve one-piece machining of the skeleton with barbs, effectively avoiding the problems of easy cracking, fatigue fracture failure, and inconvenient assembly caused by welding, gluing, threaded connection and other connection methods, and has higher flexibility and reliability to meet different skeleton manufacturing needs. Attached Figure Description

[0031] To more concisely and clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. The accompanying drawings in the following description only represent one embodiment of the present invention.

[0032] Figure 1 This is a schematic cross-sectional view of the casting device for the shell casting stage of the present invention;

[0033] Figure 2 This is an exploded schematic diagram of the casting apparatus for the shell casting stage of the present invention;

[0034] Figure 3 This is a schematic diagram of the cross-section of the tooling used in the shell drilling stage of the present invention;

[0035] Figure 4 This is a schematic diagram of the apparatus and machining process for the high-speed electrical discharge milling stage of the present invention;

[0036] Figure 5 This is an exploded schematic diagram of the hooked mesh skeleton heat treatment memory shaping stage device of the present invention;

[0037] Figure 6 This is a cross-sectional schematic diagram of the hooked mesh skeleton heat treatment memory shaping stage device of the present invention;

[0038] In the diagram: 1-Base, 2-Shell A, 3-Upper casting mold, 4-Middle casting mold, 5-Lower casting mold, 6-Shell B, 7-Magnetic locating pin, 8-Fasting screw, 9-Locking pin, 10-Nut, 11-Bolt, 12-Fasting cover, 13-Mounting adapter plate, 14-EDM milling head, 15-Guide mounting plate, 16-Hollow electrode wire, 17-Guide, 18-Mesh skeleton semi-finished product, 19-Hooked mesh skeleton, 20-Finished product shaping upper mold, 21-Finished product shaping middle mold 22-Finishing shaping lower mold, 23-Filling material, 24-Drill bit, 1901-Barb, 2001-Finishing shaping upper mold groove-shaped auxiliary flow channel, 2002-Finishing shaping upper mold gap, 2003-Finishing shaping upper mold main flow channel, 2101-Finishing shaping middle mold groove-shaped auxiliary flow channel, 2102-Finishing shaping middle mold gap, 2103-Annular boss, 2201-Finishing shaping lower mold groove-shaped auxiliary flow channel, 2202-Finishing shaping lower mold gap, 2203-Annular groove. Detailed Implementation

[0039] To facilitate understanding of the present invention, a more comprehensive description of the high-speed electrical discharge milling manufacturing method for a left atrial appendage occluder skeleton proposed in this invention will be provided below with reference to the accompanying drawings. The embodiments given in the drawings are preferred examples of a high-speed electrical discharge milling manufacturing method for a left atrial appendage occluder skeleton. However, this method can be implemented in many different forms and is not limited to the embodiments provided herein.

[0040] It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings of this specification are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of the invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," "top," "side," and "one" used in this specification are merely for clarity and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, are also considered within the scope of the invention.

[0041] A method for manufacturing a left atrial appendage occluder skeleton by high-speed electrical discharge milling includes the following steps:

[0042] A shell with the initial shape of the left atrial appendage occluder skeleton was prepared by casting a matrix, an upper casting mold, a middle casting mold, and a lower casting mold.

[0043] Holes for fixing are machined into the shell by a drill bit, and then the excess material on the shell is removed by high-speed electrical discharge milling on a multi-axis linkage electrical discharge machine tool, producing a mesh skeleton semi-finished product with barbs to be processed.

[0044] The barbs are processed sequentially using the same equipment and tooling, and then heat-treated and molded through a series of steps including the upper mold for product shaping, the middle mold for finished product shaping, the lower mold for finished product shaping, and the substrate.

[0045] After cleaning, the shell is manufactured and shaped, and the shell and the base are not separated during the entire processing.

[0046] "Preparing a shell with the initial shape of a left atrial appendage occluder skeleton by casting a matrix, an upper casting mold, a middle casting mold, and a lower casting mold" further includes:

[0047] S1: Design the base shape and shell based on the finished hooked mesh skeleton;

[0048] S2: Design casting molds and finished product shaping molds based on the base material, shell, and hooked mesh skeleton;

[0049] S3: After installing magnetic positioning pins and filler on the substrate, assemble the casting mold;

[0050] S4: After molten material is injected into a casting mold, it is cast to form shell A;

[0051] S5: Demold shell A, install the fastening cover together with the base, and install the mounting adapter plate to assemble it into a tooling.

[0052] "The process of machining holes for fixing the housing using a drill bit, followed by high-speed electrical discharge milling on a multi-axis linkage electrical discharge machine to remove excess material from the housing, resulting in a semi-finished mesh skeleton housing with barbs to be machined," further includes:

[0053] S6: Use a drill bit to drill a hole in housing A to obtain housing B. After removing the filler material from the base, install the fastening screws.

[0054] S7: Experimentally obtain the electrode wear rate of high-speed EDM milling under the corresponding working conditions and calculate the wear compensation value;

[0055] S8: Calculate and generate the toolpath trajectory for high-speed EDM machining of the skeleton using CAM software, confirm and generate machining code;

[0056] S9: Remove excess material from shell B by high-speed electrical discharge milling to create a mesh skeleton semi-finished product.

[0057] The left atrial appendage occluder skeleton is made of nickel-titanium shape memory alloy. The filler material is characterized by high temperature resistance, and is unaffected during the casting stage but can be easily removed after casting. The matrix material is a non-conductive ceramic and a non-conductive matrix, which includes various metals and non-metals with a non-conductive coating on the surface.

[0058] The electrodes used in high-speed electrical discharge milling can be hollow cylindrical electrodes. Furthermore, the electrode wire material used in high-speed electrical discharge milling is conductive, and the polarity of high-speed electrical discharge milling is positive.

[0059] Furthermore, the high-speed EDM (Electrical Discharge Milling) edge-checking function uses a voltage short-circuit signal to determine contact. High-speed EDM uses the discharge signal and its statistical information collected between electrodes as factors for servo control and loss compensation to ensure complete material removal from the machined area on the housing. High-pressure fluid is passed through the electrode wires in high-speed EDM for rapid chip removal.

[0060] First Case

[0061] like Figure 1 and Figure 2 The diagram shows a casting device for the casting stage of the shell A in a high-speed EDM milling manufacturing method for a left atrial appendage occluder skeleton according to this embodiment. A magnetic positioning pin 7 is installed in a hole at the bottom of the base 1. The threaded hole at the top of the base 1 is filled with filler 23 during the casting stage. The base 1 is positioned on the lower casting mold 5 and fixed by the magnetic positioning pin 7. The middle casting mold 4 is installed on the lower casting mold 5, and the upper casting mold 3 is installed on the middle casting mold 4. The upper casting mold 3, middle casting mold 4, and lower casting mold 5 are positioned by positioning pins 9 and fixed by nuts 10 and bolts 11.

[0062] like Figure 1 and Figure 2 As shown, the dashed boxes contain enlarged views of the main runner and the barbed runner. The dashed arrows indicate the direction of the molten liquid flow. There are molding runners between the base 1 and the upper casting mold 3, the middle casting mold 4 and the lower casting mold 5. The upper casting mold 3 has a main runner. Molten material is injected into the main runner. After the molten material fills the gap along the runner and cools and solidifies, the shell A2 with the initial shape of the left atrial appendage occluder skeleton can be obtained after demolding. The shell A2 is never removed from the base 1 during subsequent processing.

[0063] like Figure 3 The diagram shows a cross-sectional view of the tooling for the drilling stage of the housing according to the present invention. After the casting stage is completed, the magnetic positioning pin 7 is removed, and the fastening cover 12 is installed on the housing A2 to fix the housing A2 and the base 1. The mounting adapter plate 13 is installed in the hole of the base 1, thereby assembling the tooling for the drilling stage.

[0064] like Figure 3 As shown, the housing drilling stage fixture is installed on the machine tool's worktable. The drill bit 24 is fed along the direction of the dashed arrow Z to drill a hole in the top of the housing A2, thus obtaining the housing B6. At the same time, the filler is removed.

[0065] like Figure 4 The diagram shows the apparatus and machining process for the high-speed electrical discharge milling stage of this invention. The tooling for the high-speed electrical discharge milling stage is installed in a similar manner to the tooling for the housing drilling stage. After drilling a hole in housing A and removing the filler material from the base 1, fastening screws 8 are installed on the base 1 to fix the top of housing B6, thus assembling the tooling for the high-speed electrical discharge milling stage. The tooling for the high-speed electrical discharge milling stage is installed on the machine tool's worktable. The machine tool achieves multi-axis linkage attitude control of the tooling during machining by driving the mounting adapter plate 13. The hollow electrode wire 16 is mounted on the electrical discharge milling head 14, and the guide 17... The hollow electrode 16 wire is mounted on the guide mounting plate 15, which is mounted on the machine tool. The hollow electrode 16 wire passes through the guide 17 to reduce the vibration of the hollow electrode wire 16 during rotation and processing, thereby improving stability. During processing, the EDM milling head 14 can drive the hollow electrode wire 16 to rotate, and at the same time drive the hollow electrode wire 16 to feed relative to the guide 17 along the dotted line S in the figure to achieve servo-compensated feed. The discharge gap between the head of the hollow electrode wire 16 and the processing area of ​​the mesh skeleton semi-finished product 18 is controlled to be kept within a reasonable processing range, thereby ensuring a good discharge state and material removal rate, so as to ensure the complete removal of material in the processing area.

[0066] like Figure 4 As shown, in the high-speed electrical discharge milling stage, the material is removed by electrical discharge between the hollow electrode wire 16 and the mesh skeleton semi-finished product 18. By executing multiple processing codes, the skeleton and barbs 1901 are processed sequentially under the same equipment and tooling to obtain the hooked mesh skeleton 19 within the dashed box in the figure that has not undergone heat treatment and memory shaping.

[0067] like Figure 5 and Figure 6 The diagram shown is a schematic of the hooked mesh skeleton heat treatment memory shaping stage device of the present invention. Figure 6The dashed box represents a magnified view of the positional relationship between a single barb and the mold. The hooked mesh skeleton 19 is not removed after the previous step and remains fixed to the base 1 by the fastening screws 8. The magnetic positioning pin 7 is installed on the base 1. The base 1, with the hooked mesh skeleton 19 attached, is positioned on the finished product shaping lower mold 22. The outer side of the barbs 1901 of the hooked mesh skeleton 19 can precisely engage with the annular groove 2203 of the finished product shaping lower mold 22. The finished product shaping mold 21 is installed on the finished product shaping lower mold 22. The inner side of the barb 1901 of the hooked mesh skeleton 19 is just stuck on the annular boss 2103 of the finished product shaping mold 21. That is, the annular boss 2103 and the annular groove 2203 constrain the barb 1901 between them. The finished product shaping upper mold 20 is installed on the finished product shaping middle mold 21. The three molds are positioned and constrained by the positioning pin 9 and fixed by the nut 10 and bolt 11.

[0068] like Figure 5 and Figure 6 As shown, the upper mold 20 for finished product shaping has a grooved auxiliary flow channel 2001, a gap 2002, and a main flow channel 2003. The middle mold 21 for finished product shaping has a grooved auxiliary flow channel 2101 and a gap 2102. The lower mold 22 for finished product shaping has a grooved auxiliary flow channel 2201 and a gap 2202. During heat treatment and memory shaping, circulating hot air is introduced and discharged into the main flow channel 2003 of the upper mold 20 for finished product shaping, and then flows through the grooved auxiliary flow channel 2001. The gap between the upper mold and the middle mold for finished product shaping is 2002. The grooved auxiliary flow channel between the middle mold and the lower mold for finished product shaping is 2101. The gap between the lower mold and the lower mold for finished product shaping is 2201. The gap between the lower mold and the lower mold for finished product shaping ensures that the heat treatment airflow is evenly distributed. After heat treatment, the left atrial appendage occluder skeleton is obtained after shaping.

[0069] Based on the above embodiments, the present invention has significant improvements: The design model of the left atrial appendage occluder skeleton is used to reverse design the base 1, upper casting mold 3, middle casting mold 4, lower casting mold 5, finished product shaping upper mold 20, finished product shaping middle mold 21, and finished product shaping lower mold 22, and a high-speed EDM machining trajectory is generated to ensure subsequent machining accuracy; a shell A2 with the shape of the left atrial appendage occluder skeleton is obtained through precision casting, avoiding precise estimation of raw materials and improving the accuracy of the blank shape; during the casting stage, a high-temperature resistant filler is used to fill the holes of the base 1 to prevent molten liquid from blocking the fixing holes, and after demolding, the shell A2... The filler 23 is removed by drilling holes and used for fixation; the housing B6 and the base 1 are kept fixed throughout the processing using fastening screws 8 and fastening caps 12 to reduce processing errors; the material is removed by a non-contact machining method of high-speed electrical discharge milling, and the skeleton and barbs 1901 are processed sequentially under the same equipment and tooling to ensure the shape and quality of the finished left atrial appendage occluder skeleton, thereby realizing the integral molding of the skeleton and its barbs, effectively avoiding the problems of easy cracking, fatigue fracture failure and inconvenient assembly caused by welding, gluing, threaded connection and other connection methods. It has higher flexibility and reliability to meet the manufacturing needs of different skeletons.

[0070] This embodiment is based on the above-described device, combined with... Figures 1 to 6 In practice, the specific steps include:

[0071] S1: Design the shape of the base 1 and the shell A2 according to the hooked mesh skeleton 19;

[0072] S2: Based on the base 1, shell A2, hooked mesh skeleton 19, design the upper casting mold 3, middle casting mold 4, lower casting mold 5, finished product shaping upper mold 20, finished product shaping middle mold 21, and finished product shaping lower mold 22;

[0073] S3: After installing the magnetic positioning pin 7 and filler 23 on the base 1, assemble the casting mold 3, the middle casting mold 4 and the lower casting mold 5.

[0074] S4: The material is melted and injected into a casting mold to form a shell A2 with the initial shape of the left atrial appendage occluder skeleton;

[0075] S5: Demold the shell A2 from the assembly of the casting mold, install the fastening cover 12 together with the base 1, and install the mounting adapter plate 13 to assemble it into a tooling.

[0076] S6: Use drill bit 24 to drill a hole in housing A2 to obtain housing B6;

[0077] S7: Conduct parameter experiments to obtain the electrode wear rate of high-speed EDM milling under corresponding machining conditions and calculate the wear compensation value.

[0078] S8: Calculate and generate the toolpath trajectory for high-speed EDM machining of the skeleton using CAM software, confirm and generate machining code;

[0079] S9-1: Remove the filler 23 from the base 1 with the shell B6, and install the fastening screws 8 to fix the assembly into a tooling.

[0080] S9-2: Install the assembled tooling onto the machine tool's worktable;

[0081] S9-3: Operate the machine tool to perform edge alignment and determine the workpiece coordinate system;

[0082] S9-4: Execute the machining code to remove excess material from the shell B6 by high-speed electrical discharge milling to produce a mesh skeleton semi-finished product 18;

[0083] S10: Execute the machining code to process the barbs on the mesh skeleton semi-finished product 18 by high-speed electrical discharge milling to form a hooked mesh skeleton 19 that has not undergone heat treatment and memory shaping.

[0084] S11: The substrate 1 with the hooked mesh skeleton 19 is installed on the finished product shaping lower mold 22 by magnetic positioning pin 7. The finished product shaping middle mold 21 and finished product shaping upper mold 20 are installed in sequence and positioned and fixed by positioning pin 9, bolt 11 and nut 10. The hooked mesh skeleton 19 is heat treated and shaped to produce the finished hooked mesh skeleton.

[0085] S12: Clean and remove dirt from the finished hooked mesh skeleton.

[0086] The methods described in the above embodiments are original to this invention, have never been disclosed, and their working methods are different from any existing literature. (1) The base, casting mold and shaping mold are designed in reverse using the finished model of the left atrial appendage occluder skeleton. The shell with the initial shape of the left atrial appendage occluder skeleton and the barb processing area is prepared by precision casting, which ensures the quality of the blank and avoids the precise calculation of raw materials. (2) The fixing holes on the base are blocked with high temperature resistant filler and drilled after casting to remove the skeleton. This ensures that the skeleton does not detach from the base during the entire processing. At the same time, the shell is fixed to the base with fastening caps and fastening screws, which effectively reduces the deformation and movement of the shell during processing and improves the processing accuracy and processing efficiency. (3) The material is removed by using a non-contact processing method of high-speed electric spark milling. The skeleton and barbs are processed sequentially under the same equipment and tooling and then heat-treated for shaping to achieve the integral molding of the left atrial appendage occluder skeleton and its barbs, which effectively controls the shape and quality of the finished left atrial appendage occluder skeleton.

[0087] Compared with existing technologies, the performance improvements of this device / method are as follows: The shell with the initial shape of the left atrial appendage occluder skeleton and barbed machining area is prepared by casting, improving the quality of the blank and avoiding precise calculation of raw materials; the shell and substrate remain fixed throughout the entire processing, reducing machining errors and improving machining accuracy and efficiency; material is removed by a non-contact machining method using high-speed electrical discharge milling, and the skeleton and barbs are machined sequentially under the same equipment and tooling before heat treatment for shaping, achieving integrated molding of the atrial appendage occluder skeleton and its barbs. This fully utilizes the high efficiency and lack of significant contact force of high-speed electrical discharge milling, reducing the shape error of the finished skeleton and avoiding the problems of cracks and fatigue fracture failures at skeleton joints and barb welding points caused by traditional manufacturing methods, thus improving the quality of the finished left atrial appendage occluder skeleton. The design method and process proposed in this invention have better versatility and higher feasibility, and can adapt to the manufacturing of different types of left atrial appendage occluder skeletons, reducing design and manufacturing costs. The above-described specific implementations can be partially adjusted by those skilled in the art in different ways without departing from the principles and purpose of the present invention. The scope of protection of the present invention is defined by the claims and is not limited to the above-described specific implementations. All implementation schemes within the scope of the claims are bound by the present invention.

Claims

1. A method for manufacturing a left atrial appendage occluder skeleton by high-speed electrical discharge milling, characterized in that, Includes the following steps: The shell with the initial shape of the left atrial appendage occluder skeleton was prepared by casting a matrix, an upper casting mold, a middle casting mold and a lower casting mold. Holes for fixing are machined into the shell by a drill bit, and then the excess material on the shell is removed by high-speed electrical discharge milling on a multi-axis linkage electrical discharge machine tool, producing a mesh skeleton semi-finished product with barbs to be processed. The barbs are processed sequentially using the same equipment and tooling, and then heat-treated and molded through the processing steps including the upper mold for finished product shaping, the middle mold for finished product shaping, the lower mold for finished product shaping, and the base. After cleaning, the shell is manufactured and shaped, and the shell and the base are not separated during the entire processing. The casting stage further includes: S1: Design the base shape and shell based on the finished hooked mesh skeleton; S2: Design casting molds and finished product shaping molds based on the base material, shell, and hooked mesh skeleton; S3: After installing magnetic positioning pins and filler on the substrate, assemble the casting mold; S4: After molten material is injected into a casting mold, it is cast to form shell A; S5: Demold shell A, install the fastening cover together with the base, and install the mounting adapter plate to assemble it into a tooling.

2. The manufacturing method as described in claim 1, characterized in that, "The process of machining holes for fixing the housing using a drill bit, followed by high-speed electrical discharge milling on a multi-axis linkage electrical discharge machine to remove excess material from the housing, resulting in a semi-finished mesh skeleton housing with barbs to be machined," further includes: S6: Use a drill bit to drill a hole in housing A to obtain housing B. After removing the filler material from the base, install the fastening screws. S7: Experimentally obtain the electrode wear rate of high-speed EDM milling under the corresponding working conditions and calculate the wear compensation value; S8: Calculate and generate the toolpath trajectory for high-speed EDM machining of the skeleton using CAM software, confirm and generate machining code; S9: Remove excess material from shell B by high-speed electrical discharge milling to create a mesh skeleton semi-finished product.

3. The manufacturing method as described in claim 1, characterized in that, The left atrial appendage occluder skeleton is made of nickel-titanium shape memory alloy.

4. The manufacturing method as described in claim 2, characterized in that, The filler material has the characteristics of being heat-resistant, unaffected during the casting stage, and easily removed after casting.

5. The manufacturing method as described in claim 1, characterized in that, The substrate material is a non-conductive ceramic and a non-conductive substrate, and the non-conductive substrate includes various metals and non-metals with a non-conductive coating on the surface.

6. The manufacturing method as described in claim 1, characterized in that, The mold used for heat treatment memory shaping has flow channels and gaps for the circulation of hot air.

7. The manufacturing method as described in claim 1, characterized in that, The electrodes used in high-speed electrical discharge milling are hollow cylindrical electrodes.

8. The manufacturing method as described in claim 1, characterized in that, The electrode wire used in high-speed electrical discharge milling is made of conductive material, and the polarity of high-speed electrical discharge milling is positive.

9. The manufacturing method as described in claim 1, characterized in that, High-speed EDM uses voltage short-circuit signals to determine contact in the edge-to-edge function. High-speed EDM uses the discharge signals and statistical information collected between electrodes as factors for servo control and loss compensation to ensure complete removal of material from the machined area on the housing.

10. The manufacturing method as described in claim 7, characterized in that, High-pressure flushing fluid is introduced into the electrode wire during high-speed electrical discharge machining to quickly remove chips.

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