A production process for a drawbar

Abstract

The production process of the tie rod of the present invention belongs to the technical field of casting production and processing. The production process of the tie rod of the present invention includes the following steps: S1. Sand casting, using cast iron molten iron to pour and produce semi-finished tie rod castings; wherein, the semi-finished tie rod casting further includes a cylindrical process block, the cylindrical process block is integrally connected to the cantilever end of the support ear plate and is coaxially arranged with the tie rod main body; the cylindrical process block is connected to the end faces of the two support ear plates, and the outer diameter of the cylindrical process block is smaller than the outer diameter of the tie rod main body; S2. Heat treatment, annealing the semi-finished tie rod casting; S3. Machining, turning the outer circle of the tie rod main body, reaming the front pin hole and the rear pin hole, and removing the cylindrical process block; S4. Surface treatment, painting or spraying. The production process of the tie rod of the present invention can reduce the heat treatment deformation of the semi-finished tie rod casting, improve the yield rate, and improve the production efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of casting production and processing, and in particular to a production process for tie rods. Background Art

[0002] As Figure 1 and Figure 2 shown, the tie rod part is a common mechanical accessory for rail transit freight trains and large highway freight trucks, and is used for supporting the transition box plate. It is generally formed by machining a casting blank, and its main function is to transmit axial tensile and thrust forces after connecting other components through pin shafts at both ends. The specific structure: the tie rod includes a tie rod main body 1, a single-hole joint 2 and an ear plate 4 arranged coaxially. The front end of the tie rod main body 1 is integrally connected to the single-hole joint 2, and a front pin shaft hole 3 is centrally opened on the single-hole joint 2. The rear end of the tie rod main body 1 is integrally connected to two symmetrically arranged ear plates 4, and a rear pin shaft hole 5 is opened at the end of the ear plate 4. Generally, the axis lines of the front pin shaft hole 3 and the rear pin shaft hole 5 are arranged in parallel. An ear groove 6 for inserting a support arm plate is left between the two ear plates 4. In order to enable the tie rod main body 1 to obtain a larger working swing angle, the length of the ear groove 6 is relatively large, often greater than the diameters of the two tie rod main bodies 1.

[0003] After the tie rod casting blank is taken out of the sand box and the shakeout and gate and riser removal are completed, annealing treatment is often required to remove the casting stress. However, due to the influence of the casting residual stress, as Figure 2 shown, the tie rod casting blank inevitably deforms during the annealing heat treatment process. In most cases, the cantilever rear end parts of the two ear plates 4 deform inward and close together. Such serious deformation will cause the support arm plate to be unable to penetrate into the ear groove 6, resulting in the scrapping of some casting blanks and affecting the production efficiency.

[0004] In order to overcome the above problems, a production process for tie rods is needed. Summary of the Invention

[0005] The purpose of the present invention is to provide a production process for tie rods, which can reduce the heat treatment deformation of tie rod casting semi-finished products, improve the yield rate, and improve the production efficiency.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A production process for tie rods of the present invention includes the following steps:

[0008] S1. Sand casting, using cast iron molten iron to pour and produce tie rod casting semi-finished products; wherein, the tie rod casting semi-finished products further include a cylindrical process block, the cylindrical process block is integrally connected to the cantilever end of the ear plate and is coaxially arranged with the tie rod main body; the cylindrical process block is connected to the end faces of the two ear plates, and the outer diameter of the cylindrical process block is smaller than the outer diameter of the tie rod main body;

[0009] S2. Heat treatment: Anneal the semi-finished pull rod casting.

[0010] S3. Machining: Turn the outer circle of the pull rod main body, ream the front pin shaft hole and the rear pin shaft hole, and remove the cylindrical process block.

[0011] S4. Surface treatment: Spray paint or spray plastic.

[0012] Furthermore, the semi-finished pull rod casting further includes a thinning platform formed on the side of the ear plate away from the ear groove; the length of the thinning platform is aligned with the ear groove.

[0013] Furthermore, the bottom surface of the thinning platform is perpendicular to the axis line of the rear pin shaft hole, and the distance between the two thinning platforms is greater than the outer diameter of the cylindrical process block.

[0014] Furthermore, a center hole is coaxially provided on the outer end surface of the cylindrical process block.

[0015] Furthermore, an anti-deformation bowl mouth is coaxially provided on the outer end surface of the cylindrical process block, and the center hole is provided on the bottom surface of the anti-deformation bowl mouth.

[0016] Furthermore, when turning the outer circle of the pull rod main body in step S3, a turning tooling is used to clamp the single-hole joint.

[0017] Furthermore, the turning tooling is in the shape of a short cylinder, and its outer wall contacts the jaws of the lathe three-jaw chuck; a clamping groove is centrally provided on the end surface of the turning tooling facing the single-hole joint; the cross-section of the clamping groove is in the shape of an isosceles triangle, and the two inclined side surfaces of the clamping groove are respectively in contact with the outer arc wall of the single-hole joint; the width of the clamping groove is adapted to the thickness of the single-hole joint.

[0018] Furthermore, when turning the outer circle of the pull rod main body in step S3, the semi-finished pull rod casting uses a chuck to clamp the cylindrical process block at the other end or uses a lathe center to abut against the center hole.

[0019] Furthermore, in step S3, when removing the cylindrical process block, an angle grinder is used to install a cutting disc to cut off the cylindrical process block from the end surface of the ear plate.

[0020] Compared with the prior art, the beneficial technical effects of the present invention:

[0021] The tie rod production process of the present invention adds cylindrical process blocks to the cantilevered ends of the lug plates, effectively providing auxiliary supports at the cantilevered ends of the two lug plates. During the annealing process, the cantilevered ends of the lug plates are blocked by the cylindrical process blocks while residual stress is released, preventing them from closing inward. This prevents the spacing between the two lug plates from shrinking due to deformation. This process can reduce heat treatment deformation of the tie rod casting semi-finished products, improve the yield rate, and enhance production efficiency.

[0022] Furthermore, by forming a recessed thinning platform on the side of the lug plate facing away from the lug groove, the lug plate base and the tie rod body are roughly aligned on both sides, reducing left-right yaw deformation during the lug plate heat treatment. Furthermore, the thinning platform reduces material usage without significantly reducing the lug plate's strength. The presence of the thinning platform also facilitates the expansion of the rear pin hole during assembly and clamping. By adding a center hole to the outer end surface of the cylindrical process block, a lathe center can be used for auxiliary support during assembly of the semi-finished tie rod casting. By providing an anti-deformation lip on the outer end surface of the cylindrical process block, the outer wall of the cylindrical process block is thin-walled. During casting, the thin wall of the lip cools quickly and is subject to tensile stress, while the inner side of the cylindrical process block cools slowly and is subject to compressive stress. During annealing, stress relaxes, causing the thin wall of the lip to shrink, forming a closed edge. This causes the inner side of the cylindrical process block to expand outward, balancing the closing tendency of the lug plate. This anti-deformation lip not only reduces the material consumption of the cylindrical process block but also provides a reverse anti-deformation effect. By adding a turning fixture to clamp the single-hole joint, all outer diameters of the tie rod body and lug plate are cleared, allowing the entire outer diameter to be machined in a single pass. By providing a centrally located clamping slot on the outer end face of the turning fixture, the slot mates with the outer arc wall of the single-hole joint, preventing circumferential rotation while maintaining automatic centering. The coordinated use of the turning fixture and lathe center completely clears the outer diameter area that requires machining, reducing the difficulty of turning and significantly improving dimensional accuracy. The addition of the annular stop facilitates rapid positioning and installation of the turning fixture. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below with reference to the accompanying drawings.

[0024] Figure 1 It is a three-dimensional schematic diagram of an existing tie rod casting blank;

[0025] Figure 2 This is a schematic diagram of the main structure of an existing tie rod casting blank;

[0026] Figure 3 This is a schematic diagram of the three-dimensional structure of a semi-finished tie rod casting according to Example 1 of the present invention;

[0027] Figure 4 This is a schematic diagram of the main structure of a semi-finished tie rod casting according to Example 1 of the present invention;

[0028] Figure 5 It is a three-dimensional structural schematic diagram of a semi-finished product of a pull rod casting for Embodiment 2 of the present invention;

[0029] Figure 6 It is a front view sectional structural schematic diagram of the bottom of a semi-finished product of a pull rod casting for Embodiment 2 of the present invention;

[0030] Figure 7 It is a three-dimensional structural schematic diagram of a turning tooling for Embodiment 3 of the present invention;

[0031] Figure 8 It is a schematic diagram of the turning clamping state for Embodiment 3 of the present invention.

[0032] Explanation of reference numerals: 1, pull rod main body; 2, single-hole joint; 3, front pin hole; 4, support ear plate; 5, rear pin hole; 6, ear groove; 7, thinned platform; 8, cylindrical process block; 9, anti-deformation bowl mouth; 10, center hole; 11, turning tooling; 111, clamping groove; 12, lathe center. Detailed implementation manners

[0033] The core of the present invention is to provide a pull rod production process, which can reduce the heat treatment deformation of semi-finished pull rod castings, improve the qualified product rate, and improve production efficiency.

[0034] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0035] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0036] Referring to the accompanying drawings, Figure 1 It is a three-dimensional schematic diagram of an existing pull rod part; Figure 2 It is a front view structural schematic diagram of an existing pull rod part; Figure 3 It is a three-dimensional structural schematic diagram of a semi-finished product of a pull rod casting for Embodiment 1 of the present invention; Figure 4 It is a front view structural schematic diagram of a semi-finished product of a pull rod casting for Embodiment 1 of the present invention; Figure 5 It is a three-dimensional structural schematic diagram of a semi-finished product of a pull rod casting for Embodiment 2 of the present invention;Figure 6 Schematic diagram of the main view cross-section of the bottom of the semi-finished pull rod casting for Embodiment 2 of the present invention; Figure 7 Schematic three-dimensional structure diagram of the turning tooling for Embodiment 3 of the present invention; Figure 8 Schematic diagram of the turning clamping state for Embodiment 3 of the present invention. Embodiment 1

[0037] As Figure 3 and Figure 4 shown, the production process of the pull rod of the present invention includes the following steps:

[0038] S1. Sand casting, using cast iron molten iron to pour and produce semi-finished pull rod castings. Among them, most of the semi-finished pull rod castings are consistent with the existing pull rod casting blanks, including a pull rod main body 1, a single-hole joint 2, and an ear plate 4, and a front pin hole 5 is opened on the single-hole joint 2, and a rear pin hole 5 is opened on the ear plate 4. The important innovation of the process of the present invention: the semi-finished pull rod casting further includes a cylindrical process block 8, and the cylindrical process block 8 is integrally connected to the cantilever end of the ear plate 4 and is coaxially arranged with the pull rod main body 1. The cylindrical process block 8 is connected to the end faces of the two ear plates 4, and the outer diameter of the cylindrical process block 8 is smaller than the outer diameter of the pull rod main body 1.

[0039] S2. Heat treatment, annealing the semi-finished pull rod casting. When using gray cast iron material, the annealing temperature is controlled at 550 - 580 °C, heat preservation for 3 - 4 hours, and then slow cooling. It can eliminate internal stress, reduce surface hardness, and facilitate subsequent processing.

[0040] S3. Machining, turning the outer circle of the pull rod main body 1 to meet the dimensional requirements. Use a radial drill to ream the front pin hole 3 and the rear pin hole 5 so that the pin can be inserted smoothly. Remove the cylindrical process block 8.

[0041] S4. Surface treatment, painting or powder coating. After inspection, it is put into storage.

[0042] By adding a cylindrical process block 8 at the cantilever end of the ear plate 4, it is equivalent to setting auxiliary supports at the cantilever ends of the two ear plates 4. During the annealing process, when the residual stress is released, the cantilever end of the ear plate 4 is blocked by the cylindrical process block 8 and will not close inward, so that the distance between the two ear plates 4 will not shrink due to deformation. The production process of the pull rod of the present invention can reduce the heat treatment deformation of the semi-finished pull rod casting, improve the qualified rate, and improve the production efficiency.

[0043] Specifically, in step S3, when removing the cylindrical process block 8, use an angle grinder equipped with a cutting disc to cut off the cylindrical process block 8 from the end face of the ear plate 4. During the use of the angle grinder, avoid the situation that the ear plate 4 is damaged by the angle grinder cutting.

[0044] Obviously, when removing the cylindrical process block 8, a cutting tool can also be used on a lathe to cut off the cylindrical process block 8 from the end face of the ear plate 4. The advantage of this treatment is that the end face of the ear plate 4 can also be machined, and the disadvantage is that the man-hour cost is increased. Similar simple replacement methods all fall within the protection scope of the present invention.

[0045] In a specific implementation manner of this embodiment, as Figure 3 and Figure 4 shown, the semi-finished product of the pull rod casting further includes a thinning table 7, and the thinning table 7 is formed on the side of the ear plate 4 facing away from the ear groove 6 in a recessed forming manner. The length of the thinning table 7 is aligned with the ear groove 6.

[0046] Specifically, as Figure 3 and Figure 4 shown, the bottom surface of the thinning table 7 is perpendicular to the axis line of the rear pin hole 5, and two thinning tables 7 are symmetrically formed on the two ear plates 4. The distance between the two thinning tables 7 is greater than the outer diameter of the cylindrical process block 8.

[0047] By forming the thinning table 7 in a recessed manner on the side of the ear plate 4 facing away from the ear groove 6, the two sides of the part where the root of the ear plate 4 is connected to the pull rod main body 1 are made substantially the same, reducing the left-right yaw deformation during the heat treatment of the ear plate 4. At the same time, the thinning table 7 reduces the material consumption without substantially reducing the strength of the ear plate 4, and the setting of the thinning table 7 also facilitates the clamping during the reaming of the rear pin hole 5. Embodiment 2

[0048] In the above Embodiment 1, during the later turning of the outer circle of the pull rod main body 1, the cylindrical process block 8 can be clamped by a chuck method, avoiding directly clamping the cantilever end of the ear plate 4. However, a lathe center 12 is generally provided on the tailstock of a general lathe instead of a chuck tooling, so it needs to be improved.

[0049] In a specific implementation manner of this embodiment, as Figure 5 and Figure 6 shown, a center hole 10 is also coaxially provided on the outer end face of the cylindrical process block 8. The angle of the center hole 10 is 60 degrees.

[0050] By adding the center hole 10 on the outer end face of the cylindrical process block 8, the lathe center 12 can be used for auxiliary support when clamping the semi-finished product of the pull rod casting.

[0051] Specifically, an anti-deformation bowl mouth 9 is also coaxially provided on the outer end face of the cylindrical process block 8, and the center hole 10 is provided on the bottom surface of the anti-deformation bowl mouth 9.

[0052] By setting an anti-deformation bowl mouth 9 on the outer end face of the cylindrical process block 8, the outer wall opening of the cylindrical process block 8 is in a thin-wall shape. During casting, the thin-wall part of the bowl mouth cools quickly and is subjected to tensile stress; the inner side of the cylindrical process block 8 cools slowly and is subjected to compressive stress. During the annealing process, stress relaxation occurs, the thin-wall part of the bowl mouth shrinks to form a closed mouth, driving the inner side of the cylindrical process block 8 to have an outward expansion trend, which can balance the closing trend of the lug plate 4. That is, the anti-deformation bowl mouth 9 can not only reduce the material consumption of the cylindrical process block 8, but also play a role in reverse anti-deformation. Embodiment 3

[0053] Since the single-hole joint 2 of the semi-finished product of the tie rod casting is not in a cylindrical shape, three kinds of chucks cannot be used for direct clamping. In order to ensure the consistency of the outer diameter size of the tie rod main body 1, it is necessary to complete the turning process of the entire outer diameter as much as possible in one clamping, including the part where the lug plate 4 and the tie rod main body 1 are coplanar.

[0054] On the basis of the above Embodiment 2, as Figure 7 and Figure 8 shown, when turning the outer diameter of the tie rod main body 1 in step S3, a turning tooling 11 is used to clamp the single-hole joint 2.

[0055] By adding a turning tooling 11 to clamp the single-hole joint 2, all the outer diameter parts of the tie rod main body 1 and the lug plate 4 are vacated, enabling the entire outer diameter surface to be turned in one clamping.

[0056] Specifically, as Figure 7 and Figure 8 shown, the turning tooling 11 is in the shape of a short cylinder, and the outer wall contacts with the jaws of the three-jaw chuck of the lathe, that is, the outer diameter of the turning tooling 11 is directly clamped by the three-jaw chuck of the lathe spindle box. A clamping groove 111 is centrally opened on the end face of the turning tooling 11 facing the single-hole joint 2. The cross-section of the clamping groove 111 is in the shape of an isosceles triangle, and the two inclined waist surfaces of the clamping groove 111 are respectively abutted against the outer arc wall of the single-hole joint 2. The width of the clamping groove 111 is adapted to the thickness of the single-hole joint 2, that is, the single-hole joint 2 can be inserted into the clamping groove 111, and the two are in an interference fit.

[0057] By centrally opening a clamping groove 111 on the outer end face of the turning tooling 11, and the clamping groove 111 is adapted to the outer arc wall of the single-hole joint 2, it can also play a role in preventing circumferential rotation on the premise of automatic centering.

[0058] Specifically, as Figure 8 shown, when turning the outer diameter of the tie rod main body 1 in step S3, the semi-finished product of the tie rod casting is clamped by a chuck on the other end to clamp the cylindrical process block 8 or the lathe center 12 is abutted against the center hole 10.

[0059] Specifically, an annular stop is further provided on the outer wall of the turning tool 11 , and the annular stop is limited on the end face of the jaws of the three-jaw chuck, so that the turning tool 11 can be quickly positioned and installed.

[0060] By using the turning tool 11 in conjunction with the lathe center 12, the outer cylindrical portion to be processed is completely cleared, reducing the turning difficulty and significantly improving the turning dimensional accuracy.

[0061] In summary, the tie rod production process of the present invention, by adding cylindrical process blocks 8 to the cantilever ends of the lug plates 4, effectively provides auxiliary supports at the cantilever ends of the two lug plates 4. During the annealing process, the cantilever ends of the lug plates 4 are blocked by the cylindrical process blocks 8 and prevented from closing inward during residual stress release, thereby preventing the spacing between the two lug plates 4 from shrinking due to deformation. The tie rod production process of the present invention can reduce heat treatment deformation of the tie rod casting semi-finished product, improve the yield rate, and enhance production efficiency. Furthermore, by forming a recessed thinning platform 7 on the side of the lug plate 4 facing away from the lug groove 6, the connection between the base of the lug plate 4 and the tie rod body 1 is roughly aligned on both sides, reducing the left-right yaw deformation of the lug plate 4 during heat treatment. Furthermore, the thinning platform 7 reduces material usage without significantly reducing the strength of the lug plate 4. The provision of the thinning platform 7 also facilitates the expansion of the rear pin shaft hole 5 during assembly. By adding a center hole 10 to the outer end face of the cylindrical process block 8, a lathe center 12 can be used for auxiliary support when assembling the semi-finished tie rod casting. By providing an anti-deformation cup 9 on the outer end face of the cylindrical process block 8, the outer wall of the cylindrical process block 8 is thin-walled. During casting, the thin wall of the cup cools quickly and is subjected to tensile stress, while the inner side of the cylindrical process block 8 cools slowly and is subjected to compressive stress. During annealing, the stress relaxes, and the thin wall of the cup shrinks, forming a closed mouth. This drives the inner side of the cylindrical process block 8 to expand outward, balancing the closing trend of the lug plate 4. In other words, the anti-deformation cup 9 not only reduces the material consumption of the cylindrical process block 8, but also acts as a reverse anti-deformation agent. By adding a turning tool 11 to assemble the single-hole joint 2, the entire outer diameter of the tie rod body 1 and the lug plate 4 is freed up, allowing the entire outer diameter to be lathe-machined in a single assembly. By providing a centrally located mounting slot 111 on the outer end surface of the turning fixture 11, the mounting slot 111 mates with the outer arc wall of the single-hole connector 2, preventing circumferential rotation while ensuring automatic centering. The coordinated use of the turning fixture 11 and the lathe center 12 completely clears the outer diameter area to be machined, reducing turning difficulty and significantly improving dimensional accuracy. The addition of the annular stop facilitates rapid positioning and mounting of the turning fixture 11.

[0062] In this specification, the various embodiments are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the various embodiments, reference can be made to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple. For the relevant parts, reference can be made to the description in the method section.

[0063] The above-described embodiments are only descriptions of the preferred embodiments of the present invention and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A production process for a drawbar, characterized in that, It includes the following steps: S1. Sand casting is used to pour cast iron molten iron to produce semi-finished products of tie rod castings. Among them, the semi-finished products of tie rod castings include a tie rod main body (1), a single-hole joint (2) and a support ear plate (4). A front pin hole (3) is opened on the single-hole joint (2), and a rear pin hole (5) is opened on the support ear plate (4). The semi-finished products of tie rod castings also include a cylindrical process block (8). The cylindrical process block (8) is integrally connected to the cantilever end of the support ear plate (4) and is coaxially arranged with the tie rod main body (1). The cylindrical process block (8) is connected to the end faces of the two support ear plates (4), and the outer diameter of the cylindrical process block (8) is smaller than the outer diameter of the tie rod main body (1). S2. Heat treatment is carried out to anneal the semi-finished products of tie rod castings. S3. Machining is carried out. The outer circle of the tie rod main body (1) is turned, the front pin hole (3) and the rear pin hole (5) are reamed, and the cylindrical process block (8) is removed. S4. Surface treatment is carried out by painting or spraying.

2. The production process of the drawbar according to claim 1, characterized in that: The semi-finished products of tie rod castings also include a thinning table (7). The thinning table (7) is formed on the side of the support ear plate (4) facing away from the ear groove (6). The length of the thinning table (7) is aligned with the ear groove (6).

3. The production process of the pull rod according to claim 2, characterized in that: The bottom surface of the thinning table (7) is perpendicular to the axis line of the rear pin hole (5), and the distance between the two thinning tables (7) is greater than the outer diameter of the cylindrical process block (8).

4. The production process of the drawbar according to claim 1, characterized in that: A center hole (10) is also coaxially arranged on the outer end surface of the cylindrical process block (8).

5. The production process of the pull rod according to claim 4, characterized in that: An anti-deformation bowl mouth (9) is also coaxially arranged on the outer end surface of the cylindrical process block (8), and the center hole (10) is arranged on the bottom surface of the anti-deformation bowl mouth (9).

6. The production process of the pull rod according to claim 4, characterized in that, When turning the outer circle of the tie rod main body (1) in step S3, a turning tooling (11) is used to clamp the single-hole joint (2).

7. The production process of the pull rod according to claim 6, characterized in that: The turning tooling (11) is in the shape of a short cylinder, and its outer wall contacts the jaws of the lathe three-jaw chuck. A clamping groove (111) is centrally opened on the end surface of the turning tooling (11) facing the single-hole joint (2). The cross-section of the clamping groove (111) is in the shape of an isosceles triangle, and the two inclined waist surfaces of the clamping groove (111) are respectively in contact with the outer arc wall of the single-hole joint (2). The width of the clamping groove (111) is adapted to the thickness of the single-hole joint (2).

8. The production process of the drawbar according to claim 6, characterized in that: When turning the outer circle of the tie rod main body (1) in step S3, the semi-finished products of tie rod castings are clamped by a chuck at the other end for the cylindrical process block (8) or the lathe center (12) is abutted against the center hole (10).

9. The production process of the pull rod according to claim 1, characterized in that: In step S3, when removing the cylindrical process block (8), an angle grinder is installed with a cutting disc to cut off the cylindrical process block (8) from the end surface of the support ear plate (4).

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