Manufacturing process of closed spiral line impeller for centrifugal blood pump

Abstract

The application discloses a manufacturing process of a closed spiral line type impeller for a centrifugal blood pump, which comprises the following steps: S1, processing a first raw material into an integrated first impeller cover and a plurality of spiral line type blades; S2, processing a second raw material into a second impeller cover; S3, respectively performing plane grinding treatment on a first butt joint surface of the plurality of blades and a second butt joint surface of the second impeller cover; S4, performing chamfering and polishing treatment; S5, tightly pressing the first impeller cover, the plurality of blades and the second impeller cover by means of a tool clamp, so that the plurality of first butt joint surfaces are tightly attached to the second butt joint surface; S6, welding along the outer end edges of the first butt joint surfaces one by one; and S7, performing polishing treatment on the welding positions of the plurality of first butt joint surfaces and the second butt joint surface, so as to obtain the closed spiral line type impeller. The impeller is processed in a split type, no joint is formed, blood penetration is prevented, production is easy, and the application of the closed spiral line type impeller for the centrifugal blood pump is possible.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a manufacturing process for a closed spiral impeller for a centrifugal blood pump. Background Technology

[0002] The impeller is the core driving component of a blood pump. Due to biocompatibility requirements, dead corners, dead cavities, and rough surfaces are prohibited where blood flows. Any seams must be prevented from allowing blood to seep in, as these can lead to blood stagnation and thrombosis. Furthermore, sharp edges and corners are also unacceptable to avoid damage to blood cells during high-speed rotation. Unlike other media pumps, high-precision polishing is a necessary step in the manufacturing of blood pump impellers. Therefore, manufacturing these tiny impellers presents a significant challenge, as the processing methods used for impellers in other media pumps cannot be applied to blood pump impellers due to the unique characteristics of the medium, which differs from blood.

[0003] Due to the extremely high risks involved in split-type machining, blood pump impellers are currently all machined as a single piece. Therefore, most existing blood pump impellers are open impellers, semi-closed impellers, or closed impellers with straight blades. Open or semi-closed impellers have no seams and no machining dead corners, making it convenient for cutting tools or grinding tools to machine and polish them from all directions. Closed impellers are equipped with straight blades. The blades of this type of impeller can be machined as a single piece with the upper and lower cover plates. Hollow holes are left at the axis of rotation of the impeller, which can also achieve all-round machining and polishing.

[0004] Although the existing impellers can avoid the aforementioned problems such as dead angles, dead cavities, seams, sharp edges, and corners, they all come at the cost of fluid efficiency. The closed impeller with helical blades, which best meets the requirements of fluid flow and has the highest flow efficiency, has been abandoned because it requires separate manufacturing and the existing technology cannot solve the seam problem. Summary of the Invention

[0005] The problem to be solved by the present invention is to provide a manufacturing process for a closed helical impeller for a centrifugal blood pump, so as to overcome the defect that closed impellers with helical blades are difficult to process.

[0006] The technical solution adopted by this invention to solve its technical problem is: a manufacturing process for a closed-loop spiral impeller for a centrifugal blood pump, comprising the following steps:

[0007] S0, prepare the first and second raw materials required for manufacturing the impeller;

[0008] S1, the first raw material is processed into a first impeller cover of the required shape and a plurality of blades integrally connected to the first impeller cover. The plurality of blades are all spiral-shaped and are distributed in a ring at equal intervals on one side of the first impeller cover. The side of the plurality of blades facing away from the first impeller cover is set as a first mating surface, and the plurality of first mating surfaces are on the same plane.

[0009] S2, the second raw material is processed into a second impeller cover of the desired shape; wherein, the second impeller cover is provided with a second mating surface for mating with a plurality of first mating surfaces;

[0010] S3, perform surface grinding on the multiple first mating surfaces and the second mating surfaces respectively to achieve the required flatness and smoothness;

[0011] S4, the first impeller cover, the plurality of blades and the second impeller cover are chamfered and polished;

[0012] S5, using tooling fixtures to press the first impeller cover, the plurality of blades and the second impeller cover together so that the plurality of first mating surfaces are tightly fitted to the second mating surface;

[0013] S6, weld along the edge of the first mating surface away from the impeller central axis one by one to fix the multiple blades to the second impeller cover;

[0014] S7, Polish the weld joints of the first mating surfaces and the second mating surfaces to obtain a closed spiral impeller.

[0015] As a further improvement of the present invention, in S3, the first mating surface and the second mating surface are subjected to surface grinding treatment using a precision CNC surface grinder.

[0016] As a further improvement of the present invention, in S3, the flatness of the plurality of first mating surfaces and second mating surfaces after surface grinding is not greater than 0.004 mm and the smoothness is not greater than 0.2 μm.

[0017] As a further improvement of the present invention, in S4, the chamfering and polishing of the first impeller cover, the plurality of blades and the second impeller cover are performed by a combination of mechanical processing and manual labor.

[0018] As a further improvement of the present invention, the parts of the first impeller cover, the plurality of blades and the second impeller cover that are difficult to reach by mechanical processing are manually chamfered and polished. First, the chamfering is performed manually with a file, and then polishing is performed with a polishing cloth.

[0019] As a further improvement of the present invention, the tooling fixture includes a welding seat and a welding cover. The bottom of the welding seat is provided with a receiving groove, which is used to place the first impeller cover, a plurality of blades and the second impeller cover and can ensure their concentricity. The welding seat is provided with a plurality of welding windows around its outer periphery, all of which lead to the receiving groove. The plurality of welding windows are the same number as the plurality of blades and correspond one-to-one. The welding cover is used to be installed on the bottom of the welding seat and can press the first impeller cover, the plurality of blades and the second impeller cover tightly in the receiving groove.

[0020] As a further improvement of the present invention, S5 specifically includes the following steps:

[0021] S51, the first impeller cover and the plurality of blades are placed in the receiving groove;

[0022] S52, adjust the position of the first impeller cover and the plurality of blades so that the ends of the plurality of blades away from the central axis of the impeller are distributed opposite to the plurality of welding windows one by one;

[0023] S53, the second impeller cover is placed in the receiving groove, so that the second mating surface and the plurality of first mating surfaces are in contact with each other;

[0024] S54, install the welding cover on the bottom of the welding seat and press the second impeller cover tightly.

[0025] As a further improvement of the present invention, the welding method of S6 is laser welding or electron beam welding, and the first mating surface and the second mating surface are welded through the welding window.

[0026] As a further improvement of the present invention, the lower outer periphery of the welding seat is provided with an external thread, the welding cover is provided with an internal thread that matches the external thread, and a boss is provided at the top center of the welding cover. The welding cover is installed on the welding seat by means of a threaded connection, and the boss presses against the second impeller cover.

[0027] As a further improvement of the present invention, both the first raw material and the second raw material are medical-grade implantable metal materials, and the top of the first impeller cover is integrally machined with a rotor.

[0028] The beneficial effects of this invention are as follows: This invention provides a manufacturing process for a closed-loop helical impeller for a centrifugal blood pump. The impeller is processed in two parts: the helical blades are integrally processed with the first impeller cover, while the second impeller cover is processed separately. The first mating surface of the blades and the second mating surface of the second impeller cover are individually planar ground to ensure the overall flatness and smoothness of the first and second mating surfaces. This ensures a sealed state after the first and second mating surfaces come into contact, preventing blood penetration. Finally, tooling is used to ensure a tight fit between the two surfaces, and welding is performed only at the outer edge of the first mating surface. Since the weld only exists at the outer edge of the first mating surface, the internal seal is formed by the tight fit between the first and second mating surfaces without the need for further welding. This facilitates polishing of the welded area, and the internal impeller, having already undergone pre-processing, requires no further processing. This makes the manufacturing of a closed-loop helical impeller for a centrifugal blood pump possible, improving blood driving efficiency and addressing industry pain points. Attached Figure Description

[0029] Figure 1 This is a flowchart illustrating the manufacturing process of the closed helical impeller for the centrifugal blood pump of the present invention.

[0030] Figure 2 This is a perspective view of the closed helical impeller for the centrifugal blood pump of the present invention;

[0031] Figure 3 This is an exploded view of the closed helical impeller for the centrifugal blood pump of the present invention.

[0032] Figure 4 This is a perspective view of the second impeller cover of the closed helical impeller for the centrifugal blood pump of the present invention;

[0033] Figure 5 This is a perspective view of the assembly of the closed spiral impeller and tooling fixture for the centrifugal blood pump of the present invention.

[0034] Figure 6 This is an exploded view of the closed helical linear impeller and tooling fixture for the centrifugal blood pump of the present invention.

[0035] Figure 7 This is an exploded view of the closed helical impeller and tooling fixture for the centrifugal blood pump of the present invention from another perspective.

[0036] Referring to the accompanying drawings, the following explanations are provided:

[0037] 1. First impeller cover; 2. Blade; 201. First mating surface; 3. Second impeller cover; 301. Second mating surface; 4. Welding seat; 401. Receiving groove; 402. Welding window; 403. External thread; 5. Welding cover; 501. Internal thread; 502. Boss; 6. Rotor; A. Welding joint. Detailed Implementation

[0038] The preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0039] See Figures 1 to 7 The present invention provides a manufacturing process for a closed helical impeller for a centrifugal blood pump, comprising steps S0 to S7.

[0040] S0, the first and second raw materials required for manufacturing the impeller.

[0041] Both the first and second raw materials are medical-grade implantable metal materials, such as titanium alloys and cobalt alloys. In this embodiment, titanium alloy is preferred. The size and shape of the first and second raw materials are not limited and are generally determined according to the size of the impeller to be manufactured. In this embodiment, titanium alloy round bars are used.

[0042] S1, the first raw material is processed into a first impeller cover 1 of the required shape and multiple blades 2 integrally connected to the first impeller cover 1. The processing method of the first raw material in S1 can be machining, such as milling, and the first impeller cover 1 obtained by machining is generally circular.

[0043] The number of blades 2 is not limited, generally ranging from 4 to 8, but in this embodiment, it is 6. It is particularly important to emphasize that all blades 2 in this invention are helical; in other words, each blade 2 is formed by stretching a helical surface (more precisely, a segment of a helix) along the central axis of the impeller. The six blades 2 are distributed in a ring at equal intervals around the central axis of the impeller on the bottom surface of the first impeller cover 1. This helical blade design of the impeller better meets fluid flow requirements when driving blood flow, improving blood flow efficiency. The centrifugal force generated by the rotation of the blades 2 also more effectively ejects blood.

[0044] Furthermore, such as Figure 3 As shown, the side of each of the six blades 2 facing away from the first impeller cover 1 is designated as a first mating surface 201, and the six first mating surfaces 201 are on the same plane.

[0045] S2, the second raw material is processed into the second impeller cover 3 of the required shape. The processing method is the same as in step S1. The second impeller cover 3 is also circular. Preferably, the diameter of the second impeller cover 3 is the same as the diameter of the first impeller cover 1.

[0046] like Figure 4 As shown, the top surface of the second impeller cover 3 is configured as a second mating surface 301 for mating with the six first mating surfaces 201.

[0047] It should be noted that the projection of the first mating surface 201 of the six blades 2 along the central axis of the impeller can fall completely on the second mating surface 301, that is, the first mating surface 201 of the six blades 2 can be fully attached to the second mating surface 301.

[0048] It is understandable that the processing of the first raw material by S1 and the processing of the second raw material by S2 can be carried out simultaneously without distinguishing the order of their processing.

[0049] S3, perform surface grinding on the multiple first mating surfaces 201 and the second mating surfaces 301 respectively to achieve the required flatness and smoothness, so as to ensure that the multiple first mating surfaces 201 and the second mating surfaces 301 can form a planar seal after mating and fitting together, without any seams, to prevent blood penetration and avoid blood stasis and thrombosis.

[0050] In S3, the first mating surface 201 and the second mating surface 301 are surface ground using a precision CNC surface grinder. After surface grinding, the flatness of the multiple first mating surfaces 201 and the second mating surfaces 301 is no greater than 0.004mm and the surface finish is no greater than 0.2μm, so as to ensure the sealing performance when the two are tightly fitted.

[0051] S4. The first impeller cover 1, multiple blades 2 and the second impeller cover 3 are chamfered and polished to remove burrs, sharp edges and corners, so as to avoid blood cell damage during high-speed rotation.

[0052] S5, using tooling fixtures to press the first impeller cover 1, multiple blades 2 and the second impeller cover 3 together so that multiple first mating surfaces 201 are tightly attached to the second mating surface 301.

[0053] S6, weld along the edge of the first mating surface 201 away from the impeller central shaft (i.e., the outer edge of the first mating surface 201) one by one to fix the multiple blades 2 to the second impeller cover 3.

[0054] S7, the welding points A of multiple first mating surfaces 201 and second mating surfaces 301 are polished to obtain a closed spiral impeller.

[0055] like Figure 2 As shown, since weld A exists only at the outer edge of the first mating surface 201, the interior relies on the tight fit between the first mating surface 201 and the second mating surface 301 to form a seal without welding, making the polishing operation of weld A after welding convenient.

[0056] This invention processes the impeller in two parts: the helical blades 2 are integrally processed with the first impeller cover 1, while the second impeller cover 3 is processed separately. The first mating surface 201 of the blades 2 and the second mating surface 301 of the second impeller cover 3 are individually planar ground to ensure the overall flatness and smoothness of the first and second mating surfaces 201 and 301. This ensures a sealed state after the first and second mating surfaces 201 and 301 are joined, preventing blood penetration. Finally, tooling ensures a tight fit between the two parts, with welding only performed at the outer edge of the first mating surface 201. This facilitates polishing of the weld area A after welding, and the interior of the impeller, having already undergone pre-processing, requires no further processing. This makes it possible to process a closed helical impeller for centrifugal blood pumps, improving blood driving efficiency and addressing industry pain points.

[0057] See Figure 2 and Figure 3 In step S1, when machining the first raw material, a rotor 6 is integrally machined on the top of the first impeller cover 1.

[0058] In this embodiment, the rotor 6 is a hollow cylindrical shape, and the inner ends of the six blades 2 are integrally connected to the lower end of the rotor 6.

[0059] like Figure 2 As shown, the first impeller cover 1 in this embodiment has a circular hole in the middle.

[0060] In S4, the locations for chamfering and polishing include, but are not limited to: the connection between the blade 2 and the first impeller cover 1, the two ends of the blade 2, the outer periphery of the first impeller cover 1 and the edge of the circular hole, the connection between the blade 2 and the rotor 6, and the upper and lower ports of the rotor 6; however, the chamfering locations do not include the edge of the first mating surface 201, to prevent the formation of seams.

[0061] In this embodiment, the chamfer is specifically a rounded corner.

[0062] Furthermore, the chamfering and polishing of the first impeller cover 1, multiple blades 2, and the second impeller cover 3 are carried out using a combination of mechanical processing and manual labor.

[0063] Specifically, for locations easily accessible by machining, rounding can be achieved using milling machines, chamfering machines, and polishing machines. For areas of the first impeller cover 1, multiple blades 2, and the second impeller cover 3 that are difficult to reach by machining (such as the inner ends of blades 2, the connection between blades 2 and rotor 6, and the lower end of rotor 6), chamfering and polishing are performed manually. First, chamfering is done manually using a file, and then polishing is done using a polishing cloth.

[0064] See Figures 5 to 7The tooling fixture includes a welding seat 4 and a welding cover 5. The welding seat 4 is cylindrical and has a circular receiving groove 401 at its bottom. The receiving groove 401 is used to place the first impeller cover 1, multiple blades 2, and the second impeller cover 3. The inner diameter of the receiving groove 401 matches the outer diameter of the first impeller cover 1 and the second impeller cover 3 to ensure the concentricity of the first impeller cover 1 and the second impeller cover 3.

[0065] Furthermore, the welding base 4 is provided with multiple welding windows 402 around its outer periphery, all leading to the receiving groove 401. The number of welding windows 402 is the same as the number of blades 2 and they correspond one-to-one. The welding cover 5 is used to install on the bottom of the welding base 4 and can press the first impeller cover 1, the multiple blades 2 and the second impeller cover 3 into the receiving groove 401.

[0066] The welding seat 4 has an external thread 403 on its lower outer periphery, and the welding cover 5 has an internal thread 501 that matches the external thread 403 on its top. The welding cover 5 also has a boss 502 at the middle of its top. The welding cover 5 is installed on the welding seat 4 by means of a threaded connection, so that the boss 502 presses against the second impeller cover 3.

[0067] In addition, the welding seat 4 is provided with a through hole for the rotor 6 to pass through.

[0068] This embodiment S5 specifically includes the following steps:

[0069] S51, the first impeller cover 1 and multiple blades 2 are placed in the receiving groove 401, so that the rotor 6 extends outward through the through hole of the welding seat 4, and at the same time the first impeller cover 1 abuts against the top wall of the receiving groove 401.

[0070] S52, adjust the position of the first impeller cover 1 and the multiple blades 2 so that the ends of the multiple blades 2 away from the impeller central axis (i.e. the outer ends of the blades 2) are distributed opposite to the multiple welding windows 402;

[0071] S53, the second impeller cover 3 is placed in the receiving groove 401, so that the second mating surface 301 and the plurality of first mating surfaces 201 are in contact with each other;

[0072] S54, thread the welding cover 5 onto the bottom of the welding seat 4, and rotate the welding cover 5 to a suitable locking force to press it against the second impeller cover 3.

[0073] For example, the locking force is 100 to 300 Nm, preferably 200 Nm.

[0074] In this embodiment, the welding method of S6 is laser welding or electron beam welding, and the first mating surface 201 and the second mating surface 301 are welded through the welding window 402.

[0075] Therefore, the manufacturing process of the closed helical impeller for centrifugal blood pumps of the present invention involves processing the impeller in two parts: the helical blades 2 are integrally processed with the first impeller cover 1, and the second impeller cover 3 is processed separately. The first mating surface 201 of the blades 2 and the second mating surface 301 of the second impeller cover 3 are individually planar ground to ensure the overall flatness and smoothness of the first and second mating surfaces 201 and 301. This ensures that the first and second mating surfaces 201 form a seal after mating, preventing blood penetration. Finally, tooling is used to ensure a tight fit between the two. Welding is only performed at the outer edge of the first mating surface 201. Since the weld A only exists at the outer edge of the first mating surface 201, the interior relies on the tight fit between the first and second mating surfaces 201 and 301 to form a seal without further welding. This makes polishing the weld A after welding convenient. Furthermore, the interior of the impeller, having already undergone pre-processing, requires no further processing. This makes the manufacturing of the closed helical impeller for centrifugal blood pumps possible, improving blood driving efficiency and addressing industry pain points.

[0076] Many specific details have been set forth in the foregoing description to provide a thorough understanding of the present invention. However, the above description is merely a preferred embodiment of the present invention, and the present invention can be implemented in many other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed above. Furthermore, any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, using the methods and techniques disclosed above, without departing from the scope of the present invention. Any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A manufacturing process for a closed-loop helical impeller for a centrifugal blood pump, characterized in that, Includes the following steps: S0, prepare the first and second raw materials required for manufacturing the impeller; S1, the first raw material is processed into a first impeller cover (1) of the required shape and a plurality of blades (2) integrally connected to the first impeller cover (1). The plurality of blades (2) are all spiral-shaped and are distributed in a ring at equal intervals on one side of the first impeller cover (1). The side of the plurality of blades (2) facing away from the first impeller cover (1) is set as a first mating surface (201), and the plurality of first mating surfaces (201) are on the same plane. S2, the second raw material is processed into a second impeller cover (3) of the required shape; wherein the second impeller cover (3) is provided with a second mating surface (301) for mating with a plurality of first mating surfaces (201). S3, perform surface grinding on the multiple first mating surfaces (201) and the second mating surfaces (301) respectively to achieve the required flatness and smoothness; S4, the first impeller cover (1), the plurality of blades (2) and the second impeller cover (3) are chamfered and polished; S5, the first impeller cover (1), the plurality of blades (2) and the second impeller cover (3) are pressed together by tooling fixtures so that the plurality of first mating surfaces (201) are tightly attached to the second mating surface (301). S6, weld along the edge of the first mating surface (201) away from the impeller central shaft one by one to fix the multiple blades (2) to the second impeller cover (3); S7, the welding joints (A) of the multiple first mating surfaces (201) and the second mating surfaces (301) are polished to obtain a closed spiral impeller; The tooling fixture includes a welding seat (4) and a welding cover (5). The bottom of the welding seat (4) is provided with a receiving groove (401), which is used to place the first impeller cover (1), multiple blades (2), and the second impeller cover (3) and ensure their concentricity. The welding seat (4) is provided with multiple welding windows (402) around its outer periphery, all of which lead to the receiving groove (401). The number of welding windows (402) is the same as the number of blades (2) and they correspond one-to-one. The welding cover (5) is used to install on the bottom of the welding seat (4) and can connect the first impeller cover (1), multiple blades (2), and the second impeller cover (3). The impeller cover (3) is pressed into the receiving groove (401); the welding method of S6 is laser welding or electron beam welding, and the first mating surface (201) and the second mating surface (301) are welded through the welding window (402); the lower outer periphery of the welding seat (4) is provided with an external thread (403), the welding cover (5) is provided with an internal thread (501) that matches the external thread (403), and the top middle position of the welding cover (5) is provided with a boss (502). The welding cover (5) is installed on the welding seat (4) by a threaded connection, and the boss (502) presses against the second impeller cover (3).

2. The manufacturing process of the closed-loop helical impeller for a centrifugal blood pump according to claim 1, characterized in that: In S3, the first mating surface (201) and the second mating surface (301) are subjected to surface grinding using a precision CNC surface grinder.

3. The manufacturing process of the closed-loop spiral impeller for a centrifugal blood pump according to claim 2, characterized in that: In S3, the flatness of the plurality of first mating surfaces (201) and second mating surfaces (301) after surface grinding is not greater than 0.004 mm and the smoothness is not greater than 0.2 μm.

4. The manufacturing process of the closed-loop spiral impeller for a centrifugal blood pump according to claim 1, characterized in that: In S4, the chamfering and polishing of the first impeller cover (1), the plurality of blades (2) and the second impeller cover (3) are carried out by a combination of mechanical processing and manual labor.

5. The manufacturing process of the closed-loop spiral impeller for a centrifugal blood pump according to claim 4, characterized in that: For the parts of the first impeller cover (1), the multiple blades (2) and the second impeller cover (3) that are difficult to reach by mechanical processing, manual chamfering and polishing are carried out. First, manual chamfering is carried out by using a file, and then polishing is carried out by using a polishing cloth.

6. The manufacturing process of the closed helical impeller for a centrifugal blood pump according to claim 1, characterized in that, S5 specifically includes the following steps: S51, the first impeller cover (1) and the plurality of blades (2) are placed in the receiving groove (401); S52, adjust the position of the first impeller cover (1) and the plurality of blades (2) so that the ends of the plurality of blades (2) away from the central axis of the impeller are distributed one-to-one with the plurality of welding windows (402); S53, the second impeller cover (3) is placed in the receiving groove (401) so that the second mating surface (301) and the plurality of first mating surfaces (201) are in contact with each other; S54, the welding cover (5) is installed at the bottom of the welding seat (4), and the second impeller cover (3) is pressed tightly.

7. The manufacturing process of the closed-loop helical impeller for a centrifugal blood pump according to claim 1, characterized in that: Both the first raw material and the second raw material are medical-grade implantable metal materials, and the top of the first impeller cover (1) is also integrally machined with a rotor (6).

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