Extrusion die machining process

Abstract

The application discloses an extrusion die machining process, comprising the following steps: S1, obtaining a forming die, and machining a stress-reducing hole at a sharp corner position of a die hole profile of the forming die, the extension direction of the stress-reducing hole being consistent with the forming direction of the forming die; S2, machining a stress-reducing rod according to the size of the stress-reducing hole, and fitting the stress-reducing rod into the stress-reducing hole in an interference fit, the hardness of the stress-reducing rod being less than the hardness of the forming die; S3, opening a die hole in the forming die, and machining an air knife structure, the die hole and the stress-reducing hole having an intersection part; S4, obtaining a die cushion, and machining a convex surface and a die hole in the die cushion; S5, placing the forming die on the side of the die cushion on which the convex surface is machined, and assembling the forming die and the die cushion to obtain an extrusion die. The extrusion die machining process provided by the application can greatly reduce stress concentration at the sharp corner position, reduce the risk of cracking failure at the sharp corner position, prolong the service life of the forming die, reduce elastic deformation of the middle part of the forming die, and thus reduce stress concentration at the sharp corner of the die hole.

Description

Technical Field

[0001] This invention relates to the field of extrusion die processing methods, and in particular to an extrusion die processing technology. Background Technology

[0002] Large or heavy-duty extrusion presses use extrusion dies in harsh environments due to the large size and high extrusion pressure of the forming die. When extruding flat bars or profiles with sharp corners, stress concentration can easily lead to corner cracking, causing die failure or scrap. The smaller the corner radius R, the more pronounced the stress concentration and the greater the risk of die cracking. Cracking is the primary cause of failure or scrapping for these dies. For large or heavy-duty extrusion presses with a capacity of 5000 tons or more, the outer diameter of the forming die is mostly over 400 mm, with a maximum outer diameter reaching 2000 mm. A single forming die can weigh several tons, and the cost ranges from tens of thousands to hundreds of thousands of yuan. Die failure or scrapping results in significant economic losses.

[0003] In addition, the end face of the forming die is subjected to extrusion pressure, and the working belt is subjected to frictional force from the deformed metal. The forming die will undergo elastic deformation under the combined force of these two forces. When the forming die cannot withstand the ultimate stress, cracking and damage will occur.

[0004] Therefore, how to effectively improve and extend the life of extrusion dies is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a processing technology for extrusion dies to solve the problem of stress concentration at the corners during the use of extrusion dies and improve the service life of extrusion dies.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] An extrusion die processing technology includes the following steps:

[0008] Step S1: Obtain the molding die, and process stress-reducing holes at the sharp corners of the die hole contour of the molding die, wherein the extension direction of the stress-reducing holes is consistent with the molding direction of the molding die;

[0009] Step S2: Machining a stress-reducing rod according to the size of the stress-reducing hole, and inserting the stress-reducing rod into the stress-reducing hole with an interference fit. The hardness of the stress-reducing rod is less than the hardness of the forming mold.

[0010] Step S3: Open a mold hole in the forming mold and machine a hollow structure. The mold hole and the stress relief hole intersect.

[0011] Step S4: Obtain the mold pad and process the mold pad with convex surfaces and shaped holes;

[0012] Step S5: Place the forming mold on the side of the mold pad with the convex surface, and assemble the forming mold and the mold pad to obtain the extrusion mold.

[0013] Preferably, in step S3: the length of the arc intersecting the mold hole on the stress-reducing hole is ≤ 20% of the circumference of the stress-reducing hole.

[0014] Preferably, in step S1, the maximum outer diameter of the forming mold is ≤400mm, the thickness of the forming mold is ≥70mm, and the diameter of the stress-reducing hole is 5-20mm.

[0015] Preferably, the stress-reducing rod and the stress-reducing hole have the same length, and the interference fit between the stress-reducing rod and the stress-reducing hole is 0.1-0.3 mm.

[0016] Preferably, both the stress-reducing hole and the stress-reducing rod are cylindrical in shape.

[0017] Preferably, both the stress-reducing hole and the stress-reducing rod are frustum-shaped, and the larger diameter end of the stress-reducing hole and the stress-reducing rod is away from the mold pad.

[0018] Preferably, in step S1, the forming mold is a heat-resistant mold steel forming mold that has undergone heat treatment, and the hardness of the forming mold is HRC35-58.

[0019] Preferably, the stress-reducing rod is a hot-work die steel stress-reducing rod, and the hardness of the stress-reducing rod is HRC3-10 lower than the hardness of the main structure of the forming die.

[0020] Preferably, step S4 further includes:

[0021] A convex surface is machined on the inlet end face of the mold pad, and a through hole is machined on the center of the mold pad; the height T of the convex surface is controlled to be 0.1-1.0 mm.

[0022] Preferably, the convex surface is an arc surface, and the highest point of the convex surface is close to the hole of the mold pad.

[0023] The extrusion die processing technology provided by this invention includes the following steps: Step S1: Obtain a forming die and process stress-reducing holes at the sharp corners of the die hole contour of the forming die, wherein the extension direction of the stress-reducing holes is consistent with the forming direction of the forming die; Step S2: Process stress-reducing rods according to the size of the stress-reducing holes and insert the stress-reducing rods into the stress-reducing holes with an interference fit, wherein the hardness of the stress-reducing rods is less than the hardness of the forming die; Step S3: Open die holes in the forming die and process a hollow structure, wherein the die holes and the stress-reducing holes have an intersecting portion; Step S4: Obtain a die pad and process a convex surface and a shaped hole on the die pad; Step S5: Place the forming die on the side of the die pad with the convex surface processed, and assemble the forming die and the die pad to obtain an extrusion die. The extrusion die processing technology provided by this invention involves machining stress-reducing holes on the forming die and assembling stress-reducing rods within these holes. Since the die hole and the stress-reducing hole intersect, a portion of the stress-reducing rod is removed during die hole machining, becoming part of the die hole itself. Because the hardness of the stress-reducing rod is lower than that of the forming die, and because the stress-reducing rod is smaller, its uneven elastic deformation is less, thereby significantly reducing stress concentration at sharp corners, lowering the risk of cracking failure at sharp corners, and extending the service life of the forming die. Simultaneously, by machining convex surfaces on the die pad and using these convex surfaces to support the die hole positions of the forming die, the central region of the forming die can be preferentially supported during extrusion, reducing elastic deformation in the central part of the forming die, thereby reducing stress concentration at sharp corners of the die hole.

[0024] In a preferred embodiment, in step S3: the length of the arc intersecting the stress-reducing hole with the mold hole is ≤ 20% of the circumference of the stress-reducing hole. This setting avoids the problem that an excessively large arc length intersecting the stress-reducing hole with the mold hole would result in an insufficient supporting area of ​​the mold pad for the stress-reducing rod, thus weakening the clamping force of the molding die on the stress-reducing rod. This reduces the risk of misalignment or detachment of the stress-reducing rod. Therefore, a smaller arc length intersecting the stress-reducing hole with the mold hole is preferable. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the extrusion equipment.

[0027] Figure 2 A flowchart illustrating a specific embodiment of the extrusion die processing technology provided by the present invention;

[0028] Figure 3 This is a schematic diagram of the die hole processing process in the extrusion die processing technology provided by the present invention;

[0029] Figure 4 This is a schematic diagram of the processing of the die pad in the extrusion die processing technology provided by the present invention;

[0030] Figure 5 This is a schematic diagram of the die hole structure in the extrusion die processing technology provided by the present invention;

[0031] Wherein: forming mold 1; mold hole 11; stress relief hole 12; stress relief rod 13; empty knife 14; first inlet end face 15; first outlet end face 16; mold pad 2; convex surface 21; shaped hole 22; second inlet end face 23; second outlet end face 24; product 3; extrusion rod 4; extrusion pad 5; extrusion cylinder 6; ingot 7; mold sleeve 8; mold hole outline A. Detailed Implementation

[0032] The core of this invention is to provide a processing technology for extrusion dies that can significantly improve the service life of extrusion dies and reduce the risk of deformation.

[0033] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] For typical flat bar or solid profile products 3, a flat die design is used. This design is simple, the extrusion die is easy to process and maintain, and the processing cost is low. The end face of the forming die 1 bears the extrusion pressure, and the working zone bears the frictional force of the deformed metal. The extrusion die will undergo elastic deformation under the combined force of these two forces. When the die cannot withstand the ultimate stress, cracking and damage will occur, especially for flat bars or profiles with sharp corners, where stress concentration is obvious at the sharp corners. At the same time, as the radius (R) of the sharp corners decreases, the stress concentration phenomenon will be aggravated. Therefore, when designing products, the radius of the corner is generally increased as much as possible to reduce stress concentration, extend die life, and reduce die usage costs. However, increasing the radius of the corner will affect the utilization efficiency of the material in subsequent parts processing, resulting in waste. Therefore, from a cost perspective, when the extrusion die has sufficient risk resistance, a smaller radius of the corner is more conducive to improving material utilization. However, for flat bar or sharp-cornered profile products 3, regardless of the radius of the corner, minimizing the stress concentration at the sharp corners is beneficial to improving the service life of the die.

[0035] Please refer to Figures 1 to 5 As shown, Figure 1 This is a schematic diagram of the extrusion equipment. Figure 2A flowchart illustrating a specific embodiment of the extrusion die processing technology provided by the present invention; Figure 3 This is a schematic diagram of the processing of the die hole 11 in the extrusion die processing technology provided by the present invention; Figure 4 This is a schematic diagram of the processing of the die pad 2 in the extrusion die processing technology provided by the present invention; Figure 5 This is a schematic diagram of the structure of the die hole 11 in the extrusion die processing technology provided by the present invention.

[0036] In this embodiment, such as Figure 2 As shown, the extrusion die processing technology includes the following steps:

[0037] Step S1: Obtain molding mold 1, and process stress relief hole 12 at the sharp corner position of mold hole contour A of molding mold 1. The extension direction of stress relief hole 12 is consistent with the molding direction of molding mold 1.

[0038] Step S2: Machining stress relief rod 13 according to the size of stress relief hole 12, and inserting stress relief rod 13 into stress relief hole 12 with interference fit. The hardness of stress relief rod 13 is less than the hardness of forming mold 1.

[0039] Step S3: Open a mold hole 11 in the forming mold 1 and machine the hollow tool 14 structure. The mold hole 11 and the stress relief hole 12 have an intersecting part.

[0040] Step S4: Obtain the mold pad 2, and machine the convex surface 21 and the hole 22 on the mold pad 2;

[0041] Step S5: Place the forming mold 1 on the side of the mold pad 2 with the convex surface 21, and assemble the forming mold 1 and the mold pad 2 to obtain the extrusion mold.

[0042] Specifically, such as Figure 3 As shown, before machining the die hole 11, the position of the stress-reducing hole 12 is determined according to the die hole contour A. Then, the stress-reducing hole 12 is opened on the forming die 1. After machining, the stress-reducing hole 12 overlaps with the die hole contour A. Then, the stress-reducing rod 13 is installed in the stress-reducing hole 12. The stress-reducing hole 12 and the stress-reducing rod 13 have the same shape. The size of the stress-reducing rod 13 is larger than the size of the stress-reducing hole 12 to facilitate interference fit and improve connection stability. After the stress-reducing rod 13 is installed, the die hole 11 is machined along the die hole contour A. At this time, most of the die hole contour A is on the forming die 1, and a small part is on the stress-reducing rod 13.

[0043] Furthermore, the extrusion die is used in the die system, which includes a forming die 1 and a die pad 2. The die system mainly consists of the extrusion die and a die sleeve 8. The first inlet end face 15 of the forming die 1 contacts the ingot 7, and the first outlet end face 16 of the forming die 1 fits against the second inlet end face 23 of the die pad 2. The product 3 exits from the second outlet end face 24 of the die pad 2. The forming die 1 and the die pad 2 are assembled and installed inside the die sleeve 8, and used in conjunction with tools such as the extrusion cylinder 6. Depending on the assembly structure of different extruders, the forming die 1 and the die pad 2 can also be assembled without being installed inside the die sleeve 8 and used directly with the extrusion cylinder 6; the forming die 1 can be cylindrical in shape, and depending on assembly needs, it can be equipped with pin holes, keyway holes, and other structures, and a stop can be provided to engage with the die sleeve 8. Figure 1 As shown, the preferred extrusion die processing technology is for extrusion dies used in large or heavy-duty extrusion presses with a capacity of 5000 tons or more, and the maximum outer diameter of a single extrusion die is not less than 400 mm; Figure 1 As shown, the extrusion principle of the extrusion die is as follows: the ingot 7 and the extrusion pad 5 are placed in the circular hole of the extrusion cylinder 6, and the extrusion rod 4 contacts the extrusion pad 5; one end of the extrusion cylinder 6 contacts the inlet end of the assembly of the die sleeve 8, the forming die 1, and the die pad 2; the extrusion pad 5 moves towards the forming die 1 under the push of the extrusion rod 4, applying pressure to the high-temperature metal of the ingot 7 in the extrusion cylinder 6 to cause plastic deformation, and flows into the die hole 11 of the forming die 1; under the radial constraint of the die hole 11 of the forming die 1, the metal of the ingot 7 is formed into a long strip metal product 3 with a stable cross section in the length direction after passing through the die hole 11, that is, the product 3 referred to in this invention, such as a flat bar or a profile with sharp corners; the forming die 1 is provided with a blanking tool 14, and the blanking tool 14 is machined after the die hole 11 is machined, such as Figure 4 As shown, the empty cutter 14 is an enlarged hole based on the size of the die hole 11, and a working strip of different lengths is formed on the side of the die hole 11 near the entrance of the forming die 1 to adjust the metal flow rate; the die hole 11 and the empty cutter 14 form the die hole 11 of the forming die 1; a typical extrusion die for flat bars or solid profiles includes at least two parts: the forming die 1 and the die pad 2. The forming die 1 has a through die hole 11, and the die pad 2 provides support for the forming die 1 to reduce the deformation of the forming die 1 and enhance the rigidity of the die system. The die pad 2 is provided with a hole 22 for the product 3 to pass through.

[0044] The extrusion die processing technology provided by this invention involves machining stress-reducing holes 12 on the forming die 1 and assembling stress-reducing rods 13 in the stress-reducing holes 12. Since the die hole 11 and the stress-reducing hole 12 intersect, a portion of the structure of the stress-reducing rod 13 is removed during the machining of the die hole 11, forming part of the die hole 11. Because the hardness of the stress-reducing rod 13 is less than that of the forming die 1, and because the size of the stress-reducing rod 13 is smaller, the uneven elastic deformation it generates is smaller. This can significantly reduce stress concentration at sharp corner positions, reduce the risk of cracking failure at sharp corner positions, and extend the service life of the forming die 1. At the same time, by machining a convex surface 21 on the die pad 2, the convex surface 21 supports the die hole 11 position of the forming die 1. During the extrusion process, the central area of ​​the forming die 1 can be preferentially supported, reducing the elastic deformation of the central part of the forming die 1, thereby reducing the stress concentration phenomenon at the sharp corner of the die hole 11.

[0045] In some embodiments, in step S3: the length of the arc intersecting the stress-reducing hole 12 with the mold hole 11 is ≤ 20% of the circumference of the stress-reducing hole 12. This setting avoids the problem that an excessively large arc length intersecting the stress-reducing hole 12 with the mold hole 11 would result in an insufficient supporting area for the stress-reducing rod 13 by the mold pad 2, thereby weakening the clamping force of the molding mold 1 on the stress-reducing rod 13. This reduces the risk of misalignment or detachment of the stress-reducing rod 13. Therefore, a smaller arc length intersecting the stress-reducing hole 12 with the mold hole 11 is preferable.

[0046] In some embodiments, in step S1, the maximum outer diameter of the molding die 1 is ≤400mm and the thickness of the molding die 1 is ≥70mm. That is to say, the processing technology preferably produces a large-sized molding die 1 with a maximum outer diameter ≤400mm and a thickness ≥70mm.

[0047] In some embodiments, the diameter of the stress-reducing hole 12 is 5-20 mm. Specifically, the larger the diameter of the stress-reducing hole 12, the smaller the stress concentration. However, if the diameter of the stress-reducing hole 12 is too large, the edge of the stress-reducing hole 12 will be closer to the outer side of the molding die 1, which will reduce the overall strength of the molding die 1 and thus lose the purpose of improving the die life. If the diameter of the stress-reducing hole 12 is too small, stress concentration will form at the stress-reducing hole 12, and the purpose of reducing stress concentration will not be achieved. Therefore, the diameter of the stress-reducing hole 12 is preferably 8-12 mm.

[0048] In some embodiments, the stress-reducing rod 13 and the stress-reducing hole 12 have the same length, and the interference fit between the stress-reducing rod 13 and the stress-reducing hole 12 is 0.1-0.3 mm. That is, the radial dimensions of the stress-reducing rod 13 and the stress-reducing hole 12 differ by 0.1-0.3 mm to meet the interference fit requirement. Furthermore, the stress-reducing rod 13 and the stress-reducing hole 12 have the same length, that is, the length of the stress-reducing rod 13 is the same as the thickness of the molding die 1 body. This is to ensure that the stress-reducing rod 13 abuts against the die pad 2 and reduce the risk of the stress-reducing rod 13 falling off.

[0049] In some embodiments, both the stress-reducing hole 12 and the stress-reducing rod 13 are cylindrical; or, both are frustum-shaped, with the larger diameter end of the stress-reducing hole 12 and the stress-reducing rod 13 facing away from the mold pad 2. Specifically, after heat treatment, the forming mold 1 has a stress-reducing hole 12 at the pointed corner of the designed mold hole 11. The stress-reducing hole 12 is a through hole, cylindrical or frustum-shaped. When it is frustum-shaped, the inlet end is large and the outlet end is small, that is, the larger diameter end of the stress-reducing hole 12 and the stress-reducing rod 13 faces away from the mold pad 2. This arrangement is to reduce the likelihood of the stress-reducing rod 13 detaching from the stress-reducing hole 12 under the action of friction during the extrusion of the ingot 7.

[0050] In some embodiments, in step S1, the forming mold 1 is a heat-resistant mold steel forming mold 1 that has undergone heat treatment, and the hardness of the forming mold 1 is HRC35-58. By setting a larger hardness of the forming mold 1, the elastic deformation of the forming mold 1 can be reduced, the service life can be improved, and the quality of the product 3 can be improved.

[0051] In some embodiments, the stress-reducing rod 13 is made of hot-work die steel, and its hardness is HRC 3-10 lower than that of the main structure of the forming die 1. Specifically, the low strength of the stress-reducing rod 13 creates a "hard forming die 1 - soft stress-reducing rod 13" state, which can reduce stress deformation on the forming die 1 during interference fit and extrusion, thereby protecting the main body of the forming die 1. However, if the hardness of the stress-reducing rod 13 is much lower than that of the main body of the forming die 1, the stress-reducing rod 13 is prone to deformation and reduces the surface quality of the extruded product. Therefore, preferably, the hardness of the stress-reducing rod 13 is HRC 3-10 lower than that of the main structure of the forming die 1.

[0052] In some implementations, such as Figure 4 As shown, step S4 further includes:

[0053] A convex surface 21 is machined on the inlet end face of the mold pad 2, and a through hole 22 is machined on the center of the mold pad 2. The height T of the convex surface 21 is controlled to be 0.1-1.0 mm. Specifically, the convex surface 21 can be machined before or after machining the through hole 22, preferably before machining the through hole 22, that is, the convex surface 21 is machined first, and then the through hole 22 is machined, which can ensure the machining accuracy of the through hole 22.

[0054] In some embodiments, the convex surface 21 is an arc surface, and the highest point of the convex surface 21 is close to the shaped hole 22 of the die pad 2. Specifically, the shaped hole 22 is a through hole, and the cross-sectional shape of the shaped hole 22 of the die pad 2 is similar to the cross-sectional shape of the outlet of the die hole 11 of the forming die 1, and is larger than the cross-sectional shape of the outlet of the shaped hole 22 of the forming die 1, so as to ensure the passage of the extruded product 3; the second inlet end face 23 of the die pad 2 is close to the first outlet end face 16 of the forming die 1 and is assembled for use. By setting the convex surface 21 on the die pad 2 and setting the highest point of the convex surface 21 close to the shaped hole 22, it is to allow the middle area of ​​the cross-section of the forming die 1 to be supported first during extrusion, reduce the elastic deformation of the middle part of the forming die 1, and thus reduce the stress concentration phenomenon at the sharp corner of the die hole 11.

[0055] Specifically, under normal conditions, the mold will undergo uneven elastic deformation under pressure. The larger the circumscribed circle of the mold hole 11, the greater the uneven deformation, and the greater the stress concentration at the sharp corners. These sharp corners are located at the corners of the mold hole 11 with smaller chamfer radii. Specifically, the position of the stress relief hole 12 needs to be predetermined based on the mold hole contour A. Generally, such as... Figure 5 As shown, stress relief holes 12 should be provided for chamfers with a radius of less than R1mm. For chamfers with a radius of more than R15mm, stress relief holes 12 are not required. In other words, stress relief holes 12 are preferably provided in areas where stress concentration is likely to occur.

[0056] The extrusion die processing technology provided by this invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are merely for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. A processing technology for extrusion dies, characterized in that, Includes the following steps: Step S1: Obtain the molding die (1) and process stress-reducing holes (12) at the sharp corner of the die hole contour (A) of the molding die (1). The extension direction of the stress-reducing holes (12) is consistent with the molding direction of the molding die (1). Step S2: Process the stress-reducing rod (13) according to the size of the stress-reducing hole (12), and insert the stress-reducing rod (13) into the stress-reducing hole (12) with an interference fit. The hardness of the stress-reducing rod (13) is less than the hardness of the forming mold (1). Step S3: Open a mold hole (11) in the forming mold (1) and process a hollow knife (14) structure. The mold hole (11) and the stress relief hole (12) have an intersecting part. Step S4: Obtain the mold pad (2) and process the mold pad (2) with a convex surface (21) and a hole (22); Step S5: Place the forming mold (1) on the side of the mold pad (2) where the convex surface (21) is processed, and assemble the forming mold (1) and the mold pad (2) to obtain the extrusion mold.

2. The extrusion die processing technology according to claim 1, characterized in that, In step S3: the length of the arc on the stress relief hole (12) that intersects with the mold hole (11) is ≤ 20% of the circumference of the stress relief hole (12).

3. The extrusion die processing technology according to claim 1, characterized in that, In step S1, the maximum outer diameter of the forming mold (1) is ≤400mm, the thickness of the forming mold (1) is ≥70mm, and the diameter of the stress relief hole (12) is 5-20mm.

4. The extrusion die processing technology according to claim 1, characterized in that, The stress-reducing rod (13) has the same length as the stress-reducing hole (12), and the assembly interference of the stress-reducing rod (13) and the stress-reducing hole (12) is 0.1-0.3mm.

5. The extrusion die processing technology according to claim 1, characterized in that, Both the stress-reducing hole (12) and the stress-reducing rod (13) are cylindrical in shape.

6. The extrusion die processing technology according to claim 1, characterized in that, The stress-reducing hole (12) and the stress-reducing rod (13) are both frustum-shaped, and the larger diameter end of the stress-reducing hole (12) and the stress-reducing rod (13) is away from the mold pad (2).

7. The extrusion die processing technology according to claim 1, characterized in that, In step S1, the forming mold (1) is a heat-resistant mold steel forming mold (1) after heat treatment, and the hardness of the forming mold (1) is HRC35-58.

8. The extrusion die processing technology according to claim 7, characterized in that, The stress-reducing rod (13) is a hot work die steel stress-reducing rod (13), and the hardness of the stress-reducing rod (13) is HRC3-10 lower than the hardness of the main structure of the forming die (1).

9. The extrusion die processing technology according to any one of claims 1 to 8, characterized in that, Step S4 further includes: A convex surface (21) is machined on the inlet end face of the mold pad (2), and a shaped hole (22) is machined on the center of the mold pad (2), wherein the shaped hole (22) is a through hole; the height T of the convex surface (21) is controlled to be 0.1-1.0mm.

10. The extrusion die processing technology according to claim 9, characterized in that, The convex surface (21) is an arc surface, and the highest point of the convex surface (21) is close to the hole (22) of the mold pad (2).

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