Preparation method of hot stamping forming die insert and hot stamping forming die

Abstract

The invention provides a preparation method of a hot stamping forming die insert and a hot stamping forming die, and the preparation method of the hot stamping forming die insert comprises the following steps: carrying out rough machining on an obtained insert base body, and roughly forming a molded surface, and a cooling water path and a main vent hole in the molded surface; an R angle is formed between two adjacent molded surfaces; the angle R is formed into a plane, and a preset angle is formed between the plane and the two adjacent molded surfaces; a plurality of first holes are formed in the insert base body where the plane is formed, and any first hole extends from the plane to the interior of the insert base body to be communicated with the main vent hole; the plane is recessed inwards to form a groove part with the groove depth smaller than the hole depth of the first hole; a filling layer is applied to the groove part so that the groove part can be correspondingly restored to an R angle between the two adjacent molded surfaces; the filling layer is provided with a plurality of second holes which penetrate through the filling layer along the thickness direction and are communicated with the first holes; the second hole is smaller than the first hole; and the insert base body with the filling layer is subjected to finish machining and then is subjected to polishing treatment, and the hot stamping forming die insert is obtained.

Description

Technical Field

[0001] This invention belongs to the field of mold preparation technology, and particularly relates to a method for preparing a hot stamping mold insert and a hot stamping mold. Background Technology

[0002] In the existing hot stamping process, the blank will come into contact with the R-angle of the die insert, resulting in scratches on the surface of the part and wear of the die. To solve this problem, a coating is usually applied to the blank or the die, but this can only improve the situation and cannot completely solve it.

[0003] Tesla currently uses pneumatic-assisted bending technology to bend stainless steel parts, resulting in scratch-free surfaces. However, the radius (R) of the formed parts using this technology is typically only 1 mm, and the resulting R is usually straight. Theoretically, it's possible to achieve scratch-free surfaces on hot-stamped parts by filling the R of the hot-stamping die insert with extremely small holes and then ejecting high-pressure gas to force the hot-stamped blank. However, how to drill these tiny holes in the R of the hot-stamping die insert remains a problem worth exploring: using CNC drilling or EDM, the minimum diameter produced is only 1 mm, and the smaller the hole diameter, the more difficult it is to process. Therefore, these two methods cannot achieve the theoretically required hole diameter. Laser drilling can achieve a minimum hole diameter of 0.1 mm, but when the hole diameter reaches this lower limit, the hole depth is usually less than 2 mm, while the thickness at the R of the hot-stamping die insert far exceeds 2 mm. Summary of the Invention

[0004] In view of the problems existing in the prior art, the main objective of the present invention is to provide a method for preparing a hot stamping die insert.

[0005] The objective of this invention is achieved through the following technical solution: This invention provides a method for preparing a hot stamping die insert, comprising the following steps: The obtained insert substrate is rough machined to form a rough shape, including the internal cooling water channels and main vents; an R-angle is formed between two adjacent shapes. The R-angle is shaped into a plane, and the plane has a preset angle with the two adjacent surfaces; A plurality of first holes are formed on the insert substrate with a flat surface, and each of the first holes extends from the flat surface into the interior of the insert substrate and communicates with the main vent hole. The plane is recessed inward to form a groove, the depth of which is less than the depth of the first hole; A filling layer is applied to the groove to restore the groove to the R-angle between two adjacent surfaces; the filling layer has a plurality of second holes, each of which penetrates the filling layer along the thickness direction and is connected to the first hole; the diameter of the second hole is smaller than that of the first hole; The insert substrate with the filling layer applied is then finished. The precision-machined insert substrate is polished to obtain a hot-stamping mold insert.

[0006] As a further description of the above technical solution, along the transition path of two adjacent surfaces, there is at least one plane.

[0007] As a further description of the above technical solution, in the step of "forming a plurality of first holes on the insert substrate with a flat surface, wherein each first hole extends from the flat surface into the interior of the insert substrate and is connected to the main vent", the first hole is formed by CNC drilling or electrical discharge drilling. The diameter of any of the first holes is 0.5 mm to 5 mm, preferably 1 mm; Multiple first holes are arranged in an array, with the array spacing being 1-5 times the diameter of the first hole.

[0008] As a further description of the above technical solution, in the step of "making the plane concave inward to form a groove, the groove depth being less than the hole depth of the first hole", the groove is pre-formed on the plane using a CNC machine tool; the groove depth is 1 mm to 2 mm.

[0009] As a further description of the above technical solution, the step "applying a filling layer to the groove to restore the groove to the R-angle between two adjacent surfaces; the filling layer is provided with a plurality of second holes, each of which penetrates the filling layer along the thickness direction and is connected to the first hole; the diameter of the second hole is smaller than that of the first hole" specifically includes the following steps: The first hole was sealed using a high-temperature resistant material; A cladding layer is laser-clad onto the groove, the cladding layer protruding 0.5 mm to 2 mm from the surface of the insert substrate; The thickness of the cladding layer is reduced so that it becomes a filling layer flush with the surface of the insert substrate, thereby restoring the groove to the R-angle between two adjacent surfaces. Multiple second holes are formed in the filling layer by laser drilling; or, Obtain a filling layer that matches the dimensions of the groove; The filling layer is fixedly connected to the groove so that the groove is restored to the R-angle between two adjacent surfaces; Multiple second holes are formed in the filling layer by laser drilling; or, A filling layer adapted to the dimensions of the groove is obtained, and the filling layer is formed with multiple second holes by laser forming; The filling layer is fixedly connected within the groove so that the groove is restored to the radius (R) between two adjacent surfaces; or... A third hole is formed within the groove. The third hole is coaxially arranged with the first hole and extends in the same direction as the first hole. The cross-sectional area of ​​the third hole is larger than the diameter of the first hole, and the depth of the third hole is smaller than the depth of the first hole. Preferably, the depth of the third hole is 0.2 mm to 2.0 mm. A gasket that matches the size of the third hole is filled into the third hole to seal the first hole. The end face of the gasket facing away from the first hole is flush with the bottom wall of the groove. A cladding layer is laser-clad onto the groove, the cladding layer protruding 0.5 mm to 2 mm from the surface of the insert substrate; The thickness of the cladding layer is reduced so that it becomes a filling layer flush with the surface of the insert substrate, thereby restoring the groove to the R-angle between two adjacent surfaces. Multiple second holes are formed in the filling layer by laser drilling, and the second holes penetrate the gasket and communicate with the first hole. As a further description of the above technical solution, in the step "applying a filling layer to the groove to restore the groove to the R-angle between two adjacent surfaces; the filling layer has multiple second holes, each of which penetrates the filling layer along its thickness direction and communicates with the first hole; the diameter of the second hole is smaller than that of the first hole", the diameter of any second hole is 0.1 mm to 1 mm, preferably 0.1 mm to 0.5 mm. Multiple second holes are arranged in an array, with the array spacing being 1-5 times the diameter of the second hole.

[0010] As a further description of the above technical solution, the step of "polishing the finished insert substrate" includes fine polishing the main vent hole, the first vent hole and the second hole, so that the surface roughness of the main vent hole, the first vent hole and the second hole is less than Ra 1.0.

[0011] As a further description of the above technical solution, the hardness of the obtained insert substrate is less than 55HRC, preferably 25HRC-35HRC.

[0012] The present invention also provides a hot stamping forming die, comprising a hot stamping forming die insert prepared by the method described above for preparing hot stamping forming die inserts.

[0013] As a further description of the above technical solution, when hot stamping production is carried out using the hot stamping forming die, the gas pressure range introduced into the main vent is 1MPa-100MPa, preferably 20MPa-70MPa.

[0014] By employing the above technical solutions, the outstanding effects of this invention are as follows: The hot stamping die insert preparation method provided by the present invention can prepare a hot stamping die insert with dense micropores (second hole). After assembling it with other parts of the die, high pressure gas is introduced into the die. During the hot stamping process, the hot stamping blank does not come into contact with the die R-angle, so that scratch damage will not occur and the die will not wear. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a structure in one embodiment of the present invention in which the R-angle is shaped into a plane (the cooling water channel and main vent of the insert substrate are not shown); Figure 2 This is a schematic diagram showing the state of forming multiple first holes on a molded planar insert substrate in one embodiment of the present invention; Figure 3 This is a schematic diagram of a groove formed by an inwardly recessed plane in another embodiment of the present invention; Figure 4 This is a schematic diagram of a laser-clad layer on a groove in another embodiment of the present invention; Figure 5 This is a schematic diagram of a structure in another embodiment of the present invention in which a filling layer is applied to the groove and the corresponding R-angle between two adjacent surfaces is restored. Figure 6 This is a schematic diagram of a structure in another embodiment of the present invention in which the filling layer has a plurality of second holes; Figure 7 This is a cross-sectional structural diagram of a hot stamping die insert in another embodiment of the present invention; Figure 8 This is a schematic diagram of a third hole formed in a groove in another embodiment of the present invention; Figure 9 This is a schematic cross-sectional view of the groove structure in another embodiment of the present invention, showing the R-angle between two adjacent surfaces after a filling layer is applied to the groove.

[0016] Explanation of icon numbers: 1. Profile; 2. Main vent; 3. Radius; 4. Plane; 5. First hole; 6. Groove; 7. Filler layer; 8. Second hole; 9. Cladding layer; 10. Third hole; 11. Gasket. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] In the description of this invention, it should be noted that the terms "upper," "middle," "lower," "inner," "outer," "front," "rear," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The embodiments of this invention will now be described according to its overall structure.

[0019] Please see Figures 1 to 9 This embodiment discloses a method for preparing a hot stamping die insert, comprising the following steps: First, the obtained insert substrate is rough-machined to form a surface 1, as well as internal cooling water channels and main vents 2; an R-angle 3 is formed between two adjacent surfaces 1; then, the R-angle 3 is shaped into a plane 4, and the shaped plane 4 has a preset angle with the two adjacent surfaces 1; next, multiple first holes 5 are formed on the insert substrate with the shaped plane 4, each of the first holes 5 extending from the plane 4 into the interior of the insert substrate and communicating with the main vent 2; then, the plane 4 is recessed inward to form a groove 6, the groove depth of the groove 6 being less than the hole depth of the first holes 5; then, a filling layer 7 is applied to the groove 6 to restore the groove 6 to the R-angle 3 between two adjacent surfaces 1; the filling layer 7 has multiple second holes 8, each of which... The second holes 8 all penetrate the filling layer 7 along the thickness direction of the filling layer 7 and are connected to the first hole 5; the diameter of the second hole 8 is smaller than that of the first hole 5; further, the insert substrate with the filling layer 7 is then finely machined; finally, the finely machined insert substrate is polished to obtain the hot stamping die insert. The main vent 2, the first hole 5 and the second hole 8 in the hot stamping die insert prepared by this method form a high-pressure gas channel. In the hot stamping operation, the high-pressure gas enters from the main vent 2, passes through the first hole 5 and is ejected from the second hole 8, causing the hot stamping blank to be formed under force. Thus, the hot stamping blank does not contact the R-angle 3, effectively avoiding the problems of blank scratches and die wear.

[0020] Specifically, in this embodiment, along the transition path of two adjacent surfaces 1, there are multiple planes 4 (only one plane 4 is shown in the figure for ease of illustrating the hole forming process). This is because hot stamping forming dies are generally irregularly shaped surfaces 1 (i.e., the surfaces used for stamping are generally irregularly shaped), and the radius 3 between two adjacent surfaces 1 is composed of multiple arc segments. Therefore, they are formed into planes 4 one by one. The reason for processing the radius 3 into planes 4 first is that if holes are directly drilled on the arc of the radius 3, for example using CNC drilling, the drill bit is prone to slippage and breakage. However, this problem does not exist when drilling on planes 4 using CNC. For example, CNC technology can be used to form the radius 3 into planes 4.

[0021] Specifically, in this embodiment, in the step of "forming a plurality of first holes 5 on the insert substrate with the formed plane 4, wherein each of the first holes 5 extends from the plane 4 into the interior of the insert substrate and communicates with the main vent 2", the first holes 5 are formed by CNC drilling or EDM drilling; the diameter of each of the first holes 5 is 0.5 mm to 5 mm, preferably 1 mm; the plurality of first holes 5 are arranged in an array, and the array spacing is 1 to 5 times the diameter of the first holes 5. Thus, when the diameter of the first holes 5 formed on the insert substrate by CNC drilling or EDM drilling is 0.5 mm to 5 mm, the hole depth can reach 8 mm to 15 mm. This hole depth ensures the structural strength of the insert substrate while avoiding excessive processing time.

[0022] Specifically, in this embodiment, in the step of "making the plane 4 recessed inward to form a groove 6, the groove depth of the groove 6 being less than the hole depth of the first hole 5", a CNC machine tool is used to form the groove 6 on the plane 4; the groove depth of the groove 6 is 1 mm to 2 mm. It should be understood that the edge of the groove 6 can extend beyond the plane 4, thereby facilitating subsequent preparation steps. When its outer edge extends beyond the plane 4, the groove 6 extends to the bottom wall of the profile 1, which is parallel to the profile 1, to facilitate the application of the subsequent filling layer 7.

[0023] Specifically, in this embodiment, the step "applying a filling layer 7 to the groove 6 so that the groove 6 is restored to the R-angle 3 between two adjacent surfaces 1; the filling layer 7 is provided with a plurality of second holes 8, each of the second holes 8 penetrating the filling layer 7 along the thickness direction of the filling layer 7 and communicating with the first hole 5; the diameter of the second hole 8 is smaller than that of the first hole 5" specifically includes the following steps: First, the first hole 5 can be sealed with a high-temperature resistant material; then, a cladding layer 9 is laser-clad onto the groove 6, the cladding layer 9 protruding 0.5 mm to 2 mm above the surface 1 of the insert substrate and conforming to the mold surface 1; next (for example, CNC machining can be used), the thickness of the cladding layer 9 is reduced, so that the cladding layer 9 is lowered to a filling layer 7 flush with the surface 1 of the insert substrate, thereby restoring the groove 6 to the R angle 3 between two adjacent surfaces 1; finally, laser drilling is used to form multiple second holes 8 in the filling layer 7; in this process, the first hole 5 is sealed with a high-temperature resistant material before the cladding layer 9 is applied, so that the cladding material will not fall into the first hole 5 during the application of the cladding layer 9, thereby avoiding the collapse of the cladding layer 9 or the formation of pores.

[0024] Of course, in other embodiments, a sheet-like filling layer 7 adapted to the size of the groove 6 can be obtained first; then the filling layer 7 can be fixedly connected to the groove 6 so that the groove 6 is restored to the R-angle 3 between two adjacent surfaces 1; then, a laser drilling method can be used to form multiple second holes 8 in the filling layer 7; or a filling layer 7 adapted to the size of the groove 6 can be obtained first, and the filling layer 7 can be laser-formed with multiple second holes 8; then the filling layer 7 can be fixedly connected to the groove 6 so that the groove 6 is restored to the R-angle 3 between two adjacent surfaces 1. The fixed connection between the filling layer 7 and the groove 6 can be achieved, for example, by a sealing welding process.

[0025] Alternatively, in other embodiments, a third hole 10 may be formed first within the groove 6. The formed third hole 10 is coaxially arranged with the first hole 5 and extends in the same direction as the first hole 5. The cross-sectional area of ​​the third hole 10 is larger than the diameter of the first hole 5, and the depth of the third hole 10 is smaller than the depth of the first hole 5. Preferably, the depth of the third hole 10 is 0.2 mm to 2.0 mm. Then, a gasket 11, which is adapted to the size of the third hole 10, is filled into the third hole 10 to seal the first hole 5. The end face of the gasket 11 facing away from the first hole 5 is flush with the bottom wall of the groove 6. Then, in the groove... A cladding layer 9 is laser-clad onto the insert substrate. The cladding layer 9 protrudes 0.5 mm to 2 mm above the surface 1 of the insert substrate. Then (for example, using CNC machining), the thickness of the cladding layer 9 is reduced, making it a filler layer 7 flush with the surface 1 of the insert substrate. This restores the groove 6 to the R-angle 3 between adjacent surfaces 1. Finally, laser drilling is used to form multiple second holes 8 in the filler layer 7. It should be understood that, since the second holes 8 need to communicate with the first holes 5, each second hole 8 formed by laser drilling penetrates not only the filler layer 7 but also the gasket 11. In this process, the first hole 5 is first sealed with the gasket 11 before the cladding layer 9 is applied. This prevents the cladding material from falling into the first hole 5 during the application of the cladding layer 9, thus avoiding the collapse or formation of pores in the cladding layer 9.

[0026] Specifically, in this embodiment, in the step "applying a filling layer 7 to the groove 6 so that the groove 6 is restored to the R-angle 3 between two adjacent surfaces 1; the filling layer 7 is provided with a plurality of second holes 8, each of the second holes 8 penetrating the filling layer 7 along the thickness direction of the filling layer 7 and communicating with the first hole 5; the diameter of the second hole 8 is smaller than that of the first hole 5", the diameter of any second hole 8 is 0.1 mm to 1 mm, preferably 0.1 mm to 0.5 mm; the plurality of second holes 8 are arranged in an array, and the array spacing is 1 to 5 times the diameter of the second hole 8. It is possible that the plurality of second holes 8 are connected to one first hole 5.

[0027] Specifically, in this embodiment, the step of "polishing the finished insert substrate" includes fine polishing the main vent 2, the first vent, and the second hole 8, so that the surface roughness of the main vent 2, the first vent, and the second hole 8 is less than Ra1.0. The fine polishing operation can be performed by magnetic abrasive polishing or chemical polishing. The reason for performing fine polishing is that the smaller the surface roughness of the high-pressure gas channel wall formed by the main vent 2, the first vent, and the second hole 8, the smoother the gas flow and the greater the gas pressure, thereby effectively shaping the hot-stamped blank.

[0028] Specifically, in this embodiment, the hardness of the insert substrate is less than 55 HRC, preferably 25 HRC-35 HRC. The reason for setting this hardness range is that: since the R-angle 3 does not come into contact with the hot-stamped blank during the hot stamping process, there is no need to consider mold wear; in addition, the lower the hardness of the insert substrate, the easier it is to form the main vent 2 and the first hole 5.

[0029] Specifically, this embodiment also discloses a hot stamping forming die, including a hot stamping forming die insert prepared by the method described above. Furthermore, during hot stamping production using the hot stamping forming die, the gas pressure range introduced into the main vent 2 is 1MPa-100MPa, preferably 20MPa-70MPa. This gas pressure range is sufficient to form a high-pressure gas film between the die surface 1 and the hot-stamped blank, enabling non-contact forming of the hot-stamped blank.

[0030] The present invention will now be described in detail through specific embodiments: Example 1: Please see Figures 3 to 7 First, 45# steel with a hardness of 30HRC is obtained as the insert base. It is rough machined to form the surface 1, as well as the internal cooling water channel and main vent 2. An R angle 3 with a length shorter than the two surfaces 1 is formed between two adjacent surfaces 1. Then, the R-angle 3 position is CNC machined to form a plane 4 with an angle of 45° to the horizontal plane 4. The plane 4 has a preset angle with the two adjacent surfaces 1. Next, a CNC drilling process is used to form multiple first holes 5 with a diameter of 1 mm on the insert substrate with a formed plane 4. Each first hole 5 extends from the plane 4 into the interior of the insert substrate and connects to the main vent 2. The hole spacing is 2 mm, the array length is along the length direction of the plane 4, and 6 rows of first holes 5 are distributed in the array width direction. Of course, in other embodiments, the specific number of rows and columns of the first holes can be set according to actual needs.

[0031] Then, using CNC technology, the plane 4 is recessed inward to form a groove 6 with a depth of 1 mm; Then, the first hole 5 is sealed with molten high-temperature wax, and a cladding layer 9 is laser-clad on the groove 6. The thickness of the cladding layer 9 is 2 mm. After the laser cladding is completed, the thickness of the cladding layer 9 is reduced by CNC process, so that the cladding layer 9 is reduced to a filling layer 7 that is flush with the surface 1 of the insert substrate. This restores the groove 6 to the R angle 3 between two adjacent surfaces 1. At this time, multiple second holes 8 are formed on the filling layer 7 by laser drilling. Each second hole 8 penetrates the filling layer 7 along the thickness direction of the filling layer 7 and is connected to the first hole 5 (therefore, the depth of the second hole 8 is 1 mm). The second holes 8 are also arranged in an array. The diameter of each second hole 8 is 0.1 mm and the hole spacing is 0.5 mm. Furthermore, the insert substrate with the filling layer 7 is further precision machined to ensure that its dimensions and specifications meet the accuracy requirements for subsequent thermoforming operations. Finally, magnetic grinding and polishing are used to polish the finished insert substrate to obtain the hot stamping mold insert. The fine polishing is mainly applied to the inner walls of the main vent 2, the first hole 5 and the second hole 8, so that their roughness is reduced to Ra0.6.

[0032] Example 2: like Figures 1 to 2 As shown, firstly, H13 mold steel with a hardness of 35HRC is obtained as the insert base, and it is rough machined to form the surface 1, as well as the internal cooling water channel and main vent 2; an R angle 3 with the same length as the two surfaces 1 is formed between two adjacent surfaces 1. Then, the R-angle 3 position is CNC machined to form a plane 4 with an angle of 45° to the horizontal plane 4. The plane 4 has a preset angle with the two adjacent surfaces 1. Next, a CNC drilling process is used to form multiple first holes 5 with a diameter of 2 mm on the insert base with a plane 4. Each first hole 5 extends from the plane 4 into the interior of the insert base and is connected to the main vent 2. The hole spacing is 3 mm, the array length is along the length direction of the plane 4, and 6 rows of first holes 5 are distributed in the array width direction.

[0033] Then, using CNC technology, the plane 4 is recessed inward to form a groove 6 with a depth of 2 mm; Next, a 2mm thick sheet-like filling layer 7 conforming to the radius 3 is machined using CNC technology. This filling layer 7 is then welded into the groove 6 using a sealing welding method, so that the groove 6 corresponds to the radius 3 between two adjacent surfaces 1. Then, multiple second holes 8 are formed on the filling layer 7 using laser drilling. Each second hole 8 penetrates the filling layer 7 along its thickness direction and is connected to the first hole 5 (therefore, the depth of the second hole 8 is 2mm). The second holes 8 are also arranged in an array, with each second hole 8 having a diameter of 0.5mm and a spacing of 1.0mm. The surface roughness of the second holes 8 is Ra1.0 at this time. Furthermore, the insert substrate with the filling layer 7 is further precision machined to ensure that its dimensions and specifications meet the accuracy requirements for subsequent thermoforming operations. Finally, magnetic grinding and polishing are used to polish the finished insert substrate to obtain the hot stamping mold insert. The fine polishing is mainly applied to the inner walls of the main vent 2, the first hole 5 and the second hole 8, so that their roughness is reduced to Ra0.3.

[0034] Example 3: like Figures 1 to 2 As shown, firstly, H13 mold steel with a hardness of 35HRC is obtained as the insert base, and it is rough machined to form the surface 1, as well as the internal cooling water channel and main vent 2; an R angle 3 with the same length as the two surfaces 1 is formed between two adjacent surfaces 1. Then, the R-angle 3 position is CNC machined to form a plane 4 with an angle of 45° to the horizontal plane 4. The plane 4 has a preset angle with the two adjacent surfaces 1. Next, a CNC drilling process is used to form multiple first holes 5 with a diameter of 1 mm on the insert base with a 2 mm diameter drill bit. Each first hole 5 extends from the plane 4 into the interior of the insert base and is connected to the main vent 2. The hole spacing is 3 mm, the array length is along the length direction of the plane 4, and 6 rows of first holes 5 are distributed in the array width direction.

[0035] Then, using CNC technology, the plane 4 is recessed inward to form a groove 6 with a depth of 1 mm; Then as Figures 8 to 9 As shown, a third hole 10 is formed in the groove 6 using CNC technology. The formed third hole 10 is coaxially arranged with the first hole 5 and extends in the same direction as the first hole 5. The cross-section of the third hole 10 is circular, with a diameter of 1.2 mm and a depth of 0.5 mm. Then, a gasket 11 with a diameter of 1.2 mm and a thickness of 0.5 mm is placed in the third hole 10 (of course, in other embodiments, the cross-section of the third hole may also be non-circular, but its cross-sectional area is larger than the diameter of the first hole). A cladding layer 9 is then laser-clad onto the groove 6. The thickness of the cladding layer 9 is 2 mm. After the laser cladding is completed, the thickness of the cladding layer 9 is reduced by CNC process, so that the cladding layer 9 is reduced to a filling layer 7 that is flush with the surface 1 of the insert substrate. This restores the groove 6 to the R angle 3 between two adjacent surfaces 1. At this time, multiple second holes 8 are formed on the filling layer 7 by laser drilling. Each second hole 8 penetrates the filling layer 7 and the gasket 11 along the thickness direction of the filling layer 7 and is connected to the first hole 5 (therefore, the hole depth of the second hole 8 is 1.5 mm). The second holes 8 are also arranged in an array. The diameter of each second hole 8 is 0.1 mm and the hole spacing is 0.5 mm. Furthermore, the insert substrate with the filling layer 7 is further precision machined to ensure that its dimensions and specifications meet the accuracy requirements for subsequent thermoforming operations. Finally, magnetic grinding and polishing are used to polish the finished insert substrate to obtain the hot stamping mold insert. The fine polishing is mainly applied to the inner walls of the main vent 2, the first hole 5 and the second hole 8, so that their roughness is reduced to Ra0.6.

[0036] The application performance of the thermoforming mold inserts prepared in Examples 1 and 2 were tested respectively, and the specific test results are as follows: When the thermoforming mold insert in Example 1 is assembled into the thermoforming mold for hot stamping production testing, a high-pressure gas of 30MPa is introduced into the main vent 2. The high-pressure gas flows from the main vent 2 to the first hole 5, and then is ejected at high speed from the second hole 8, forming a high-pressure gas film between the mold surface 1 and the hot-stamped blank. The hot-stamped blank achieves non-contact forming with the R-angle 3. In Example 2, when the thermoforming mold insert is assembled into the thermoforming mold for hot stamping production testing, a high-pressure gas of 60MPa is introduced into the main vent 2. The high-pressure gas flows from the main vent 2 to the first hole 5, and then is ejected at high speed from the second hole 8, forming a high-pressure gas film between the mold surface 1 and the hot-stamped blank. The hot-stamped blank achieves non-contact forming with the R-angle 3.

[0037] In Example 3, when the thermoforming mold insert is assembled into the thermoforming mold for hot stamping production testing, a high-pressure gas of 40MPa is introduced into the main vent 2. The high-pressure gas flows from the main vent 2 to the first hole 5, and then is ejected at high speed from the second hole 8, forming a high-pressure gas film between the mold surface 1 and the hot-stamped blank. The hot-stamped blank achieves non-contact forming with the R-angle 3.

[0038] Therefore, the hot stamping die insert preparation method provided by the present invention can prepare a hot stamping die insert with dense micropores (second hole 8). After assembling it with other parts of the die, high pressure gas is introduced into the die. During the hot stamping process, the hot stamping blank does not come into contact with the die R angle 3, so that scratch damage will not occur and the die will not wear.

[0039] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any changes, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a hot stamping die insert, characterized in that, Includes the following steps: The obtained insert substrate is rough machined to form a rough shape, including the internal cooling water channels and main vents; an R-angle is formed between two adjacent shapes. The R-angle is shaped into a plane, and the plane has a preset angle with the two adjacent surfaces; A plurality of first holes are formed on the insert substrate with a flat surface, and each of the first holes extends from the flat surface into the interior of the insert substrate and communicates with the main vent hole. The plane is recessed inward to form a groove, the depth of which is less than the depth of the first hole; A filling layer is applied to the groove to restore the groove to the R-angle between two adjacent surfaces; the filling layer has a plurality of second holes, each of which penetrates the filling layer along the thickness direction and is connected to the first hole; the diameter of the second hole is smaller than that of the first hole; The insert substrate with the filling layer applied is then finished. The precision-machined insert substrate is polished to obtain a hot-stamping mold insert.

2. The method for preparing the hot stamping die insert according to claim 1, characterized in that, Along the transition path between two adjacent surfaces, there is at least one plane.

3. The method for preparing the hot stamping die insert according to claim 1, characterized in that, In the step "forming a plurality of first holes on the insert substrate with a flat surface, wherein each first hole extends from the flat surface into the interior of the insert substrate and communicates with the main vent", the first hole is formed by CNC drilling or electrical discharge drilling. The diameter of any of the first holes is 0.5 mm to 5 mm, preferably 1 mm; Multiple first holes are arranged in an array, with the array spacing being 1-5 times the diameter of the first hole.

4. The method for preparing the hot stamping die insert according to claim 1, characterized in that, In the step of "making the plane concave inward to form a groove, the groove depth being less than the hole depth of the first hole", the groove is pre-formed on the plane using a CNC machine tool; the groove depth is 1 mm to 2 mm.

5. The method for preparing the hot stamping die insert according to claim 1, characterized in that, The step "Applying a filling layer to the groove to restore the groove to the R-angle between two adjacent surfaces; the filling layer has a plurality of second holes, each of which penetrates the filling layer along its thickness direction and is connected to the first hole; the diameter of the second hole is smaller than that of the first hole" specifically includes the following steps: The first hole was sealed using a high-temperature resistant material; A cladding layer is laser-clad onto the groove, the cladding layer protruding 0.5 mm to 2 mm from the surface of the insert substrate; The thickness of the cladding layer is reduced so that it becomes a filling layer flush with the surface of the insert substrate, thereby restoring the groove to the R-angle between two adjacent surfaces. Multiple second holes are formed in the filling layer by laser drilling; or, Obtain a filling layer that matches the dimensions of the groove; The filling layer is fixedly connected to the groove so that the groove is restored to the R-angle between two adjacent surfaces; Multiple second holes are formed in the filling layer by laser drilling; or, A filling layer adapted to the size of the groove is obtained, and the filling layer is formed with a plurality of second holes by laser forming; or, a third hole is formed in the groove, the third hole is coaxially arranged with the first hole and has the same extension direction as the first hole; the cross-sectional area of ​​the third hole is larger than the diameter of the first hole, and the depth of the third hole is smaller than the depth of the first hole. A gasket that matches the size of the third hole is filled into the third hole to seal the first hole. The end face of the gasket facing away from the first hole is flush with the bottom wall of the groove. A cladding layer is laser-clad onto the groove, the cladding layer protruding 0.5 mm to 2 mm from the surface of the insert substrate; The thickness of the cladding layer is reduced so that it becomes a filling layer flush with the surface of the insert substrate, thereby restoring the groove to the R-angle between two adjacent surfaces. The filling layer is formed with multiple second holes by laser drilling, and the second holes penetrate the gasket and communicate with the first hole; The filling layer is fixedly connected to the groove so that the groove is restored to the R-angle between two adjacent surfaces.

6. The method for preparing the hot stamping die insert according to claim 1, characterized in that, In step "Apply a filling layer to the groove to restore the groove to the R-angle between two adjacent surfaces; the filling layer has a plurality of second holes, each of which penetrates the filling layer along the thickness direction and is connected to the first hole; the diameter of the second hole is smaller than that of the first hole", the diameter of any second hole is 0.1 mm to 1 mm, preferably 0.1 mm to 0.5 mm. Multiple second holes are arranged in an array, with the array spacing being 1-5 times the diameter of the second hole.

7. The method for preparing the hot stamping die insert according to claim 1, characterized in that, The step "polishing the finished insert substrate" includes fine polishing the main vent, the first vent, and the second hole, so that the surface roughness of the main vent, the first vent, and the second hole is less than Ra 1.

0.

8. The method for preparing the hot stamping die insert according to claim 1, characterized in that, The hardness of the obtained insert substrate is less than 55 HRC, preferably 25 HRC-35 HRC.

9. A hot stamping forming die, characterized in that, This includes hot stamping mold inserts prepared using the hot stamping mold insert preparation method as described in claims 1 to 8.

10. The hot stamping forming die according to claim 9, characterized in that, When hot stamping production is carried out using the hot stamping forming die, the gas pressure range introduced into the main vent is 1MPa-100MPa, preferably 20MPa-70MPa.

Images