Extrusion die and design method

Abstract

The invention discloses an extrusion die and a design method, and relates to the technical field of die design, specifically, the extrusion die comprises a pre-deformation cavity and a shaping cavity which are arranged in a die main body and are communicated, the projection area of the pre-deformation cavity in the axial direction of the die is larger than the projection area of the shaping cavity in the axial direction of the die, and the pre-deformation cavity and the shaping cavity are arranged in the die main body. According to the extrusion die and the design method, the pre-deformation cavity is additionally arranged in the die, and the metal flow velocity of a bar in the die is regulated and controlled, so that the flow velocity difference of extruded metal at different parts of a metal fin profile is reduced, and the extrusion efficiency of the metal fin profile is improved. And the structure property difference of each part is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of die design, and more specifically, to an extrusion die. In addition, the present invention also relates to a die design method applied to the extrusion die. Background Art

[0002] With the advancement of science and technology, the development trend of aluminum alloy profiles for aerospace is high-precision size, complex cross-sectional shape, high surface quality requirements and high organizational uniformity.

[0003] In the prior art, mold design mainly relies on production experience. Different alloys and different cross-sectional sizes determine different dimensional shrinkage rates based on the empirical parameter range. After the new mold is tried, it is repaired according to the actual production situation. Some molds cannot be repaired after one trial or multiple iterations of mold repair, resulting in the mold being scrapped. At present, for high-precision and complex cross-section profiles, the one-time pass rate of the mold is very low, which is far from meeting the current requirements for high-precision, high-performance and high surface quality of aluminum alloy profiles for aviation.

[0004] For example Figure 1 The aviation fin profile shown includes a main body portion 1 and a fin portion, wherein the fin portion includes a first fin 2, a second fin 3 and a vertical rib portion 4. The metal fin profile has a complex shape, a large difference in wall thickness, and a narrow range of dimensional accuracy. Users have high requirements for the uniformity of the structural properties of the profile at different positions. In actual production, the extruded metal flow at different parts of the profile is very different, which makes it difficult to control the high-precision dimensional deviation of each part, and at the same time increases the difference in the structural properties of each part.

[0005] Therefore, how to solve the problem that when the existing die is used to extrude metal fin profiles, the flow of extruded metal in different parts is very different, and the difference in the organization and performance of each part is increasing. This is a technical problem that technicians in this field need to solve urgently. Summary of the invention

[0006] In view of this, the purpose of the present invention is to provide an extrusion die, by adding a pre-deformation cavity in the die, the metal flow rate of the bar in the die is regulated, thereby reducing the difference in metal flow rate of extrusion in different parts of the metal fin profile and reducing the difference in organizational performance of each part.

[0007] Another object of the present invention is to provide a die design scheme applied to the above-mentioned extrusion die, which can design an implementable extrusion die to ensure that the dimensional accuracy of the extruded metal fin profile is controllable and the structural properties of each part are uniform.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] An extrusion die is used for processing a metal fin profile including a main body and a fin part, the extrusion die includes a pre-deformation cavity and a shaping cavity which are arranged in the die main body and are connected, the projection area of ​​the pre-deformation cavity in the axial direction of the die is larger than the projection area of ​​the shaping cavity in the axial direction of the die, and the projection of the pre-deformation cavity in the axial direction of the die completely covers the projection of the shaping cavity in the axial direction of the die;

[0010] The projection of the shaping cavity in the axial direction of the mold is the same as the cross section of the metal fin profile along its own axial direction.

[0011] Preferably, the ratio of the projected area of ​​the pre-deformation cavity in the axial direction of the mold to the projected area of ​​the shaping cavity in the axial direction of the mold is the extrusion ratio, and the extrusion ratio at the corresponding position of the main body is smaller than the extrusion ratio at the corresponding position of the fin part.

[0012] Preferably, the distance between the center line of the pre-deformation cavity at the corresponding position of the main body and the axis of the mold is smaller than the distance between the center line of the pre-deformation cavity at the corresponding position of the fin part and the axis of the mold.

[0013] Preferably, the length of the pre-deformation cavity at the corresponding position of the main body along the axial direction of the mold is less than or equal to the length of the pre-deformation cavity at the corresponding position of the fin portion along the axial direction of the mold.

[0014] Preferably, a transition structure is provided at the connection position between the pre-deformation cavity and the shaping cavity.

[0015] Preferably, it further comprises a die pad fixedly arranged at the discharge end of the molding cavity, wherein a discharge channel and a main body channel are arranged in the die pad;

[0016] The material discharge channel is in communication with the shaping cavity and is used for the metal fin profile to pass through;

[0017] A plurality of groups of local channels are arranged in communication between the main channel and the feeding channel.

[0018] Preferably, the cross section of the main channel in a direction perpendicular to the axial direction of the die pad is an annular structure, and the annular structure surrounds the feed channel.

[0019] Preferably, the number of local channels between the main channel and the feed channel at the corresponding position of the fin portion is not less than the number of local channels between the main channel and the feed channel at the corresponding position of the main portion.

[0020] Preferably, both ends of the main channel are closed, and a channel entrance communicating with the main channel is provided in the mold pad.

[0021] A die design method, applied to any of the above extrusion dies, comprises the following steps:

[0022] Obtaining a cross section M1 of the metal fin profile along its own axial direction;

[0023] Obtain an upward projection M2 of the molding cavity along the mold axis, wherein the projection M2 is the same as the cross section M1;

[0024] Obtain an upward projection M3 of the pre-deformation cavity along the mold axis, wherein the projection M3 completely covers the projection M2;

[0025] According to the area ratio of the projection M3 to the projection M2, the length H of the pre-deformation cavity along the axial direction of the mold is calculated.

[0026] Preferably, according to the area ratio of the projection M3 to the projection M2, the length H of the pre-deformation cavity along the axial direction of the mold is calculated, including:

[0027] According to the maximum wall thickness of the metal fin profile With minimum wall thickness The length H is corrected according to the ratio of .

[0028] Compared with the prior art, the extrusion die provided by the present invention has at least the following beneficial effects:

[0029] By adding a pre-deformation cavity in the mold, the rod is extruded once in the pre-deformation cavity, and then the metal flow rate in the pre-deformation cavity is regulated. When the rod enters the shaping cavity, the metal flow rate difference in different parts is small, which helps to improve the uniformity of the organizational properties of different parts of the extruded metal fin profile, and helps to improve the dimensional accuracy control of the extruded metal profile.

[0030] The die design method provided by the present invention is applied to the above-mentioned extrusion die, and can design the above-mentioned extrusion die, which is helpful to improve the dimensional accuracy and uniformity of the structural performance of the extruded metal fin profile. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0032] Figure 1 is a cross-sectional view of a metal fin profile to be processed;

[0033] Figure 2A schematic diagram of the structure of the extrusion die provided by the present invention;

[0034] Figure 3 It is a schematic diagram of the projection of the pre-deformation cavity and the shaping cavity provided by the present invention in the axial direction of the mold;

[0035] Figure 4 A schematic diagram of the structure of the mold pad provided by the present invention;

[0036] Figure 5a This is a photo of a metal fin profile extruded from an extrusion die without a pre-deformed cavity;

[0037] Figure 5b This is a photo of a metal fin profile extruded by the extrusion die provided by the present invention;

[0038] Figure 6a It is a local characteristic diagram of a metal fin profile extruded by an extrusion die without a pre-deformation cavity;

[0039] Figure 6b A local characteristic diagram of a metal fin profile extruded by an extrusion die provided by the present invention;

[0040] Figure 7 The invention provides a mold design method.

[0041] In the figure:

[0042] 1. Main body; 2. First fin; 3. Second fin; 4. Vertical rib; 5. Pre-deformation cavity; 6. Forming cavity; 7. Mold body; 8. Mold pad; 9. Channel inlet; 10. Main channel; 11. Local channel. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] The core of the present invention is to provide an extrusion die, by adding a pre-deformation cavity in the die, the metal flow rate of the bar in the die is regulated, thereby reducing the difference in metal flow rate of different parts of the metal fin profile and reducing the difference in organizational performance of each part.

[0045] Another core of the present invention is to provide a die design scheme including the above-mentioned extrusion die, which can design an implementable extrusion die to ensure that the dimensional accuracy of the extruded metal fin profile is controllable and the organizational properties of each part are uniform.

[0046] Please refer to Figure 2 and Figure 3 , an extrusion die, used for processing a metal fin profile including a main body 1 and a fin part, the extrusion die including a pre-deformation cavity 5 and a shaping cavity 6 which are arranged in a die main body 7 and are connected, the projection area of ​​the pre-deformation cavity 5 in the axial direction of the die is larger than the projection area of ​​the shaping cavity 6 in the axial direction of the die, and the projection of the pre-deformation cavity 5 in the axial direction of the die completely covers the projection of the shaping cavity 6 in the axial direction of the die;

[0047] The projection of the molding cavity 6 in the axial direction of the mold is the same as the cross section of the metal fin profile along its own axial direction.

[0048] like Figure 2 and Figure 3 As shown, a connected pre-deformation cavity 5 is arranged at the upstream end of the shaping cavity 6, and the projection area of ​​the pre-deformation cavity 5 along the axial direction of the mold is larger than the projection area of ​​the shaping cavity 6 along the axial direction of the mold, and the projection area of ​​the pre-deformation cavity 5 along the axial direction of the mold completely covers the projection area of ​​the shaping cavity 6 along the axial direction of the mold, and a reserved distance is provided between the projection edge of the pre-deformation cavity 5 along the axial direction of the mold and the projection edge of the shaping cavity 6 along the axial direction of the mold to accommodate the flow of metal.

[0049] like Figure 1 As shown, the metal fin profile is a symmetrical structure, with the main body 1 in the middle and the fins on both sides. The wall thickness of the main body 1 is greater than that of the fins. Therefore, during extrusion molding, the metal flow rate corresponding to the main body 1 in the mold is greater than the metal flow rate corresponding to the fins, resulting in different extrusion metal flow rates at different positions of the metal fin profile, making it difficult to control the dimensional accuracy of the profile, and the organizational properties of each part are uneven;

[0050] By adding a pre-deformation cavity 5, whose projection along the axial direction of the mold is similar to the outer contour of the profile, the rod is pre-deformed when passing through the pre-deformation cavity 5, and the rod fills the pre-deformation cavity 5 during the process. The metal flow rate of the rod is regulated, and the metal flow rate difference in the molding cavity 6 at the corresponding position of the main body 1 and the fin part is reduced, thereby facilitating the improvement of the dimensional accuracy control of the extruded profile and improving the uniformity of the organizational properties of various parts of the extruded profile.

[0051] In some embodiments, the ratio of the projected area of ​​the pre-deformation cavity 5 in the axial direction of the mold to the projected area of ​​the shaping cavity 6 in the axial direction of the mold is the extrusion ratio, and the extrusion ratio at the corresponding position of the main body 1 is smaller than the extrusion ratio at the corresponding position of the fin part.

[0052] like Figure 1As shown, the wall thickness of the main body 1 of the metal fin profile is greater than the wall thickness of the first fin 2, the second fin 3 and the vertical rib 4 in the fin portion. Therefore, setting the extrusion ratio of the corresponding position of the main body 1 to be smaller than the extrusion ratio of the corresponding position of the fin portion can reduce the metal flow rate at the corresponding position of the main body 1 in the pre-deformation cavity 5, while increasing the metal flow rate at the corresponding position of the fin portion, thereby reducing the metal flow rate difference between the corresponding positions of the main body 1 and the fin portion in the pre-deformation cavity 5, ultimately improving the dimensional accuracy control and organizational performance uniformity of the extruded profile.

[0053] In some embodiments, the distance between the center line of the pre-deformation cavity 5 at the corresponding position of the main body 1 and the mold axis is smaller than the distance between the center line of the pre-deformation cavity 5 at the corresponding position of the fin portion and the mold axis.

[0054] like Figure 3 As shown in the figure, the intersection of the dotted lines is the axis position of the mold. Because the wall thickness of the main body 1 is greater than the wall thickness of the fin part, the metal flow rate at the corresponding position of the main body 1 in the mold is greater than the metal flow rate at the corresponding position of the fin part. Therefore, the distance between the center line of the corresponding position of the main body 1 in the pre-deformation cavity 5 and the mold axis is set to be smaller than the distance between the center line of the corresponding position of the fin part and the mold axis. Therefore, the flow distance of the metal in the mold perpendicular to the axial direction of the mold can be shortened, the flow resistance of the metal can be reduced, and the extrusion efficiency of the profile can be improved, while reducing the heat generation during the extrusion process.

[0055] At the same time, the distance relationship between the center line of the corresponding position of the main body 1 and the fin part in the molding cavity 6 and the mold axis is consistent with the relationship in the pre-deformation cavity 5, that is, the distance between the center line of the molding cavity 6 at the corresponding position of the main body 1 and the mold axis is smaller than the distance between the center line of the molding cavity 6 at the corresponding position of the fin part and the mold axis, further reducing the flow distance of the metal in the mold perpendicular to the axial direction of the mold.

[0056] In some embodiments, the length of the pre-deformation cavity 5 at the corresponding position of the main body 1 along the axial direction of the mold is less than or equal to the length of the pre-deformation cavity 5 at the corresponding position of the fin portion along the axial direction of the mold.

[0057] When designing the pre-deformation cavity 5, it is preferred that the overall axial length of the pre-deformation cavity 5 is consistent, which can reduce the difficulty of design and processing;

[0058] However, in some embodiments, because the extrusion ratios of the corresponding positions of the main body 1 and the fin part in the extrusion die are different at the pre-deformation cavity 5 and the shaping cavity 6, and when the rod is fed in the pre-deformation cavity 5, metal needs to flow to completely fill the cross-section of the pre-deformation cavity 5, and the metal flow rate at the corresponding position of the fin part is slower, it is designed that the axial length of the mold at the corresponding position of the fin part in the pre-deformation cavity 5 is greater than the axial length of the corresponding position of the main body 1, so that the corresponding positions of the main body 1 and the fin part in the pre-deformation cavity 5 are completely filled with the metal of the rod.

[0059] In some embodiments, a transition structure is provided at the connection position between the pre-deformation cavity 5 and the shaping cavity 6 .

[0060] A chamfer is provided at the connection position between the pre-deformation cavity 5 and the shaping cavity 6, and the radius of the chamfer is preferably 3-5 mm, thereby reducing the resistance of the metal flowing between the pre-deformation cavity 5 and the shaping cavity 6, thereby improving the profile extrusion efficiency and reducing the profile extrusion heat generation.

[0061] In some embodiments, it also includes a die pad 8 fixedly arranged at the discharge end of the molding cavity 6, and a discharge channel and a main body channel 10 are arranged in the die pad 8;

[0062] The material discharge channel is connected to the shaping cavity 6 for the metal fin profile to pass through;

[0063] A plurality of groups of local channels 11 are arranged in communication between the main channel 10 and the material discharge channel.

[0064] In the extrusion die, the bar is extruded into a metal profile. The internal metal flow generates a lot of heat, making its chemical properties active and easy to react with oxygen in the air, resulting in a decrease in the final surface quality and dimensional accuracy of the profile. Therefore, an additional Figure 4 The die pad 8 shown in the figure has a feed channel inside which can wrap the metal profile just extruded, and continuously replenishes low-temperature nitrogen or inert gas into the feed channel through the main channel 10 to quickly cool the metal profile, and utilizes nitrogen or other inert gas protection to avoid surface quality degradation caused by high-temperature oxidation of the profile surface.

[0065] Liquid nitrogen or other low-temperature inert gas is preferably introduced into the main channel 10.

[0066] In some embodiments, the cross section of the main channel 10 in a direction perpendicular to the axial direction of the die pad 8 is an annular structure, and the annular structure surrounds the feed channel.

[0067] like Figure 4 As shown, the cross section of the main channel 10 perpendicular to the axial direction of the die pad 8 is an annular structure, and the annular structure surrounds the feed channel, that is, there is only a thin wall between the main channel 10 and the feed channel. When low-temperature gas or liquid is introduced into the main channel 10, heat is directly exchanged with the feed channel through the thin wall, thereby increasing the heat exchange area, improving the heat exchange efficiency, and making the temperature in the feed channel uniform, so as to promote rapid cooling of the extruded profile;

[0068] At the same time, the main channel 10 of the annular structure facilitates the local channels 11 to be dispersedly arranged at different positions of the material discharge channel, so that the low-temperature gas or liquid can quickly contact the surface of the extruded profile to avoid surface oxidation.

[0069] In some embodiments, the number of local channels 11 between the main channel 10 and the feed channel at corresponding positions of the fin portion is not less than the number of local channels 11 between the main channel 10 and the feed channel at corresponding positions of the main body 1 .

[0070] like Figure 4 As shown, the surface area of ​​the fin portion of the metal fin profile is larger than the surface area of ​​the main body 1, so more local channels 11 are set at the corresponding positions of the fin portion, so that the gas in the main channel 10 can quickly fill the corresponding positions of the fin portion, thereby making the gas in the discharge channel evenly distributed, avoiding oxidation of the fin portion due to low gas concentration.

[0071] In some embodiments, both ends of the main channel 10 are closed, and a channel inlet 9 connected to the main channel 10 is provided in the mold pad 8 .

[0072] Both ends of the main channel 10 are closed to form a closed space, and liquid nitrogen is injected only through the channel inlet 9, which helps to increase the gas pressure in the main channel 10, and then helps to increase the gas flow rate in the local channel 11, so that the liquid nitrogen can be quickly vaporized and fill the feeding channel, thereby ensuring the nitrogen concentration in the feeding channel, improving the cooling efficiency of the extruded profile, and preventing the extruded profile from being oxidized.

[0073] In some embodiments, the axial length of the pre-deformation cavity 5 along the mold is set to 10-15 mm, the vertical height of the corresponding position of the main body 1 in the pre-deformation cavity 5 is set to 15-20 mm, and the vertical height of the corresponding position of the fin portion is set to 25-30 mm;

[0074] The distance between the upper surface of the main body 1 at the corresponding position in the molding cavity 6 and the axis of the extrusion mold is 8-15mm, the width of the main channel 10 in the mold pad 8 is 4-8mm, the wall thickness between the main channel 10 and the feeding channel is 4-8mm, and the inner diameter of the local channel 11 is 3-6mm.

[0075] In addition to the extrusion dies disclosed in the above embodiments, the present invention also provides a die design method applied to the above extrusion dies, such as Figure 7 As shown, the following steps are included:

[0076] Obtain the cross section M1 of the metal fin profile along its own axial direction;

[0077] Obtain an upward projection M2 of the mold cavity 6 along the mold axis, and the projection M2 is the same as the cross section M1;

[0078] Obtain an upward projection M3 of the pre-deformed cavity 5 along the mold axis, and the projection M3 completely covers the projection M2;

[0079] According to the area ratio of the projection M3 to the projection M2, the length H of the pre-deformation cavity 5 along the axial direction of the mold is calculated.

[0080] The axial section M1 of the metal fin profile is obtained by measurement, and the projection M2 of the mold cavity 6 with the same shape and area is formulated according to the section M1. The extrusion ratio λ is determined according to the ductility of the bar metal and the extrusion speed, and the projection M3 is drawn from the root projection M2, and the optimal shape of the projection M3 is obtained through the finite element simulation software;

[0081] Finally, the length H of the pre-deformation cavity 5 in the axial direction of the mold is calculated according to the formula;

[0082] The calculation formula for length H is:

[0083]

[0084] Where D is the circumscribed circle diameter of the metal fin profile (mm);

[0085] K is the correction factor (0.08-0.12, the upper limit value is taken for complex sections).

[0086] In some embodiments, the extrusion ratio λ1 at the corresponding position of the main body 1 in the pre-deformation cavity 5 and the shaping cavity 6 is smaller than the extrusion ratio λ2 at the corresponding position of the fin part, so the lengths H1 and H2 of the pre-deformation cavity 5 at the corresponding position of the main body 1 and the fin part in the axial direction of the mold are calculated respectively;

[0087] Specifically:

[0088] The length H1 of the pre-deformation cavity 5 at the corresponding position of the main body 1 in the axial direction of the mold is

[0089]

[0090] The length H2 of the pre-deformation cavity 5 at the corresponding position of the fin part in the axial direction of the mold,

[0091]

[0092] In some embodiments, the length H of the pre-deformation cavity 5 along the axial direction of the mold is calculated according to the area ratio of the projection M3 to the projection M2, including:

[0093] According to the maximum wall thickness of the metal fin profile With minimum wall thickness The length H is corrected according to the ratio of .

[0094] For some metal fin profiles, the ratio of the maximum wall thickness to the minimum wall thickness is greater than or equal to 2, and the length of the pre-deformation cavity 5 needs to be revised, referring to the formula:

[0095]

[0096] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0097] The extrusion die and design method provided by the present invention are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. An extrusion die for processing a metal fin profile comprising a main body (1) and a fin portion, characterized in that: It comprises a pre-deformation cavity (5) and a shaping cavity (6) which are arranged in a mold body (7) and are connected to each other, the projection area of ​​the pre-deformation cavity (5) in the axial direction of the mold is larger than the projection area of ​​the shaping cavity (6) in the axial direction of the mold, and the projection of the pre-deformation cavity (5) in the axial direction of the mold completely covers the projection of the shaping cavity (6) in the axial direction of the mold; The projection of the shaping cavity (6) in the axial direction of the mold is the same as the cross section of the metal fin profile along its own axial direction.

2. The extrusion die according to claim 1, characterized in that: The ratio of the projected area of ​​the pre-deformation cavity (5) in the axial direction of the mold to the projected area of ​​the shaping cavity (6) in the axial direction of the mold is the extrusion ratio, and the extrusion ratio at the corresponding position of the main body (1) is smaller than the extrusion ratio at the corresponding position of the fin portion.

3. The extrusion die according to claim 1, characterized in that: The distance between the center line of the pre-deformation cavity (5) at the corresponding position of the main body (1) and the axis of the mold is smaller than the distance between the center line of the pre-deformation cavity (5) at the corresponding position of the fin portion and the axis of the mold.

4. The extrusion die according to claim 1, characterized in that: The length of the pre-deformation cavity (5) at a corresponding position of the main body (1) along the axial direction of the mold is less than or equal to the length of the pre-deformation cavity (5) at a corresponding position of the fin portion along the axial direction of the mold.

5. The extrusion die according to claim 1, characterized in that: A transition structure is provided at the connection position between the pre-deformation cavity (5) and the shaping cavity (6).

6. The extrusion die according to claim 1, characterized in that: It also comprises a die pad (8) fixedly arranged at the discharge end of the molding cavity (6), wherein a discharge channel and a main body channel (10) are arranged in the die pad (8); The material discharge channel is in communication with the shaping cavity (6) and is used for the metal fin profile to pass through; A plurality of groups of local channels (11) are arranged in communication between the main channel (10) and the material discharge channel.

7. The extrusion die according to claim 6, characterized in that: The cross section of the main channel (10) in a direction perpendicular to the axial direction of the die pad (8) is an annular structure, and the annular structure surrounds the feed channel.

8. The extrusion die according to claim 7, characterized in that: The number of local channels (11) between the main channel (10) and the feed channel at corresponding positions of the fin portion is not less than the number of local channels (11) between the main channel (10) and the feed channel at corresponding positions of the main portion (1).

9. The extrusion die according to claim 7, characterized in that: Both ends of the main channel (10) are closed, and a channel inlet (9) communicating with the main channel (10) is provided in the die pad (8).

10. A die design method, applied to the extrusion die according to any one of claims 1 to 9, characterized in that: The following steps are involved: Obtaining a cross section M1 of the metal fin profile along its own axial direction; Obtaining an upward projection M2 of the molding cavity (6) along the mold axis, wherein the projection M2 is the same as the cross section M1; Obtaining an upward projection M3 of the pre-deformation cavity (5) along the mold axis, wherein the projection M3 completely covers the projection M2; The length H of the pre-deformation cavity (5) along the axial direction of the mold is calculated based on the area ratio of the projection M3 to the projection M2.

11. The method for designing a mold according to claim 10, characterized in that: The length H of the pre-deformation cavity (5) along the axial direction of the mold is calculated based on the area ratio of the projection M3 to the projection M2, including: According to the maximum wall thickness of the metal fin profile With minimum wall thickness The length H is corrected according to the ratio of .

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