A multi-angular door frame forming die and its processing method

Abstract

The present invention discloses a multi-angled door frame forming die and its processing method, which includes a lower die base and an upper die body. On the lower die base, there are a first cylinder located at both ends and a second cylinder located in the middle. The output end of the first cylinder is equipped with a connector, and the top of the connector is installed with a middle die body through bolts. The top of the middle die body is provided with a primary forming area adapted to the forming area of the upper die body. On the lower die base, there is a lower die body located below the connector, and the output end of the second cylinder is connected to the bottom of the lower die body. The area between the lower die body and the lower die base is the secondary forming area. The surfaces of the middle die body, the lower die body, and the upper die body are all provided with a Ti-xY wear-resistant alloy layer. By using the primary forming of the folding structure adapted to the upper die body and the primary forming area, and the micro short-distance retraction of the cylinder piston rod to complete the final forming of the folding structure, only one set of modules and two steps of processes are required, the efficiency is greatly improved, and the accuracy can also be guaranteed. By using this alloy layer, it is beneficial to reduce the wear resistance, reduce the wear rate, and improve the service life.

Description

Technical Field

[0001] The present invention relates to the technical field of door frame bending and forming, and particularly relates to a multi-angled door frame forming die and a processing method thereof. Background Art

[0002] A bending machine die is divided into an upper die, a lower die and a die base of the bending machine, and is a die used for sheet metal bending forming and separation. As Figure 6 shown, the door frame structure in the figure has seven bending structures. In particular, the key structure at point A in the door frame structure has a folding structure, and this folding structure generally requires four bends to complete, and it needs to be positioned reciprocally four times. Since there are errors in each positioning, the bending accuracy of this key structure is greatly reduced, and the production efficiency also needs to be further optimized.

[0003] Moreover, due to the key structure having a folding structure, when initially bending the folding structure, it is bound to cause wear of the bending die. If the traditional 42CrMo material is still used as the die raw material, its wear resistance cannot meet the existing working conditions. For example, therefore, it is necessary to further improve the wear resistance of the bending die. Summary of the Invention

[0004] The purpose of the present invention is to solve the deficiencies in the prior art. Therefore, a multi-angled door frame forming die and a processing method thereof are proposed. By using a cylinder as the support for the lower die body and the middle die body, and utilizing the initial forming of the folding structure adapted to the forming area of the upper die body and the slightly short-distance retraction of the cylinder piston rod to complete the final forming of the folding structure, it only requires one set of modules and two steps to complete, the efficiency is greatly improved, and the accuracy can also be guaranteed. Using this alloy layer can help reduce the wear resistance, reduce the wear rate, and improve the service life.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A multi-angled door frame forming die includes a lower die base and an upper die body. On the lower die base, a first cylinder is installed at both ends and a second cylinder is installed in the middle. The output end of the first cylinder is installed with a connector, and the top of the connector is installed with a middle die body through bolts. The top of the middle die body is provided with an initial forming area adapted to the forming area of the upper die body. A lower die body is also installed on the lower die base below the connector. The output end of the second cylinder is connected to the bottom of the lower die body. The area between the lower die body and the lower die base is a secondary forming area. The surfaces of the middle die body, the lower die body, and the upper die body are all provided with a Ti-xY wear-resistant alloy layer.

[0007] Based on the above embodiments, the following improvements are made. The lower die body includes a connecting portion connected to the output end of the second cylinder and sliding relative to the lower die base, and a secondary forming pressing head integrally connected to the connecting portion. A secondary forming area is defined between the bottom surface of the secondary forming pressing head and the top surface of the lower die base, and a positioning area is defined between the top surface of the secondary forming pressing head and the bottom surface of the connecting head located directly above the secondary forming pressing head.

[0008] Based on the above embodiments, the following improvements are made. The connecting head includes a mounting portion mounted on the middle die body through bolts, and connecting heads disposed at both ends of the bottom surface of the mounting portion and fixedly connected to the output ends of the corresponding first cylinders.

[0009] Based on the above embodiments, the following improvements are made. The primary forming area includes an L-shaped fold, a V-shaped fold, and a horizontal bearing platform arranged in sequence from the right front to the back. The L-shaped fold is inclined, and the top of the L-shaped fold and the horizontal bearing platform are coplanar.

[0010] Based on the above embodiments, the following improvements are made. The lower die base is provided with mounting grooves for mounting the first cylinder and the second cylinder, and threaded holes are arranged on the side of the mounting grooves.

[0011] Based on the above embodiments, the following improvements are made to the manufacturing processes of the middle die body, the lower die body, and the upper die body. The processing steps are as follows: subject the middle die body, the lower die body, and the upper die body made of 42CrMo as the raw material to nitriding and then oxidation treatment. Prepare a deposition solution by mixing tetraethoxysilane, ammonia water with a mass fraction of 25% - 28%, pure water, and absolute ethanol in a ratio of 1:4 - 5:7 - 8:3 - 4. Place the heat-treated middle die body, lower die body, and upper die body in 25 - 35 times the amount of the deposition solution, and perform ultrasonic reaction at 45 - 60 Hz for 2 - 4 h. Then add nano-yttrium oxide in an amount of 0.02 - 0.08 times the amount of tetraethoxysilane, and perform ultrasonic reaction at 45 - 60 Hz for 2 - 4 h. Take out and wash twice with 250 mL of pure water, wash twice with 180 mL of 95% ethanol, dry at 85 - 95 °C for 4 - 6 h. Subsequently, place it in a reactor, evacuate to make the pressure reach 3.5 - 4.5 MPa, introduce gaseous titanium tetrachloride in an amount of 0.05 - 0.12 times the amount of tetraethoxysilane, raise the temperature of the reactor to 330 - 350 °C, evacuate again to make the pressure reach 3.5 - 4.5 MPa, and then introduce a mixed reducing gas until the pressure reaches 75 - 95 MPa. Then, with the temperature of the middle die body, the lower die body, and the upper die body being 800 - 1200 °C, deposit for 5 - 8 h.

[0012] After the nitrided 42CrMo is oxidized, the surface of the nitrided layer will contain magnetite and have a certain magnetism. A silicon solution is prepared by mixing tetraethoxysilane, ammonia water with a mass fraction of 25% - 28%, pure water, and absolute ethanol in a certain proportion. Under ultrasonic reaction, it is deposited in two times. First, silica is coated on the outside of magnetite, and they are combined through stable Si - O - Fe chemical bonds to obtain the initial deposition layer. Then, due to the introduction of yttrium oxide into the silicon solution, a stable Si - O - Y chemical bond exists, which will form the final deposition layer. Thus, a porous silica layer doped with yttrium is deposited on the surface of the nitrided layer. Subsequently, in the gaseous titanium tetrachloride atmosphere, titanium tetrachloride will enter the porous silica and undergo cross - linking, hydrolysis, and condensation reactions with the amino groups on it to form a titanium dioxide cross - linked network. Finally, it is reduced at high temperature in a methane - containing reducing atmosphere to form titanium carbide. Since yttrium is doped in the silica layer, when titanium carbide is formed, yttrium can make the primary titanium carbide dendrites become fine, increase the dendrite spacing, and increase the amount of slender eutectic titanium carbide to obtain ultrafine - grained titanium carbide. The ultrafine - grained titanium carbide increases the interfacial wettability at the yttrium - purified interface, enabling it to be evenly dispersed in the silica layer and having a high density. When microcracks and residual stresses occur around the ultrafine - grained titanium carbide, it can pin the cracks and consume the fracture energy, thereby improving the toughness of the coating material.

[0013] In the above - mentioned further technical solution, the mixed reducing gas includes one or more of hydrogen and silane in addition to methane. When silane is added, silicon carbide can be distributed in the titanium carbide crystal and has a high density, and binary and / or ternary eutectic phases will appear.

[0014] The forming method of a multi - segment angular door frame uses the above - mentioned forming die, and the forming process includes:

[0015] Step 1: Place the plate at the positioning area on the horizontal plane composed of the L - shaped fold angle and the horizontal base.

[0016] Step 2: The upper die body moves downwards, and the plate is folded into the initial shape of a folded - back structure through the forming area at the lower part of the upper die body and the initial forming area of the middle die body. Then the upper die body moves upwards and resets.

[0017] Step 3: Take away the plate with the initial folded - back structure processed, insert the unprocessed horizontal section into the positioning area between the lower die body and the installation part, and position the right angle of the initial shape of the folded - back structure through the outer wall of the secondary forming pressure head. At the same time, the V - shaped structure of the initial folded - back structure is inside the secondary forming area.

[0018] Step 4: Place the new sheet on the positioning area of the horizontal plane formed by the L-shaped fold and the horizontal base. Lower the upper die body to form a preliminary shape of the folded-back structure on the new sheet. At the same time, the V-shaped structure located at the secondary forming area can be folded into the final shape of the folded-back structure. Description of the Drawings

[0019] Figure 1 Side view of the overall structure of the present invention;

[0020] Figure 2 Front view of the overall structure of the present invention;

[0021] Figure 3 Connection diagram of the lower die body and the lower die base of the present invention;

[0022] Figure 4 Side view of the lower die body of the present invention;

[0023] Figure 5 Side view of the lower die base of the present invention;

[0024] Figure 6 Structural schematic diagram of the final workpiece of the present invention.

[0025] In the figure: 10, lower die base; 11, cylinder one; 12, cylinder two; 13, connector; 131, installation part; 132, joint; 14, middle die body; 15, lower die body; 151, connection part; 152, secondary forming pressure head; 16, L-shaped fold; 17, V-shaped fold; 19, installation groove; 20, upper die body. Detailed Description of the Invention

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0027] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0028] Embodiment 1: As Figures 1 to 6As shown in the figure, a pneumatic upper and lower die for forming a door frame includes a lower die base 10 and an upper die body 20. On the lower die base 10, a first cylinder 11 is installed at both ends and a second cylinder 12 is installed in the middle. Installation grooves 19 for installing the first cylinder 11 and the second cylinder 12 are arranged on the lower die base 10, and threaded holes are arranged on the side of the installation grooves 19.

[0029] A connecting head 13 is installed at the output end of the first cylinder 11. The connecting head 13 includes an installation part 131 for installing the middle die body 14 by bolts and a connecting part 132 arranged at both ends of the bottom surface of the installation part 131 and fixedly connected to the output end of the corresponding first cylinder 11. The top of the connecting head 13 (installation part 131) is installed with a middle die body 14 by bolts. An initial forming area adapted to the forming area of the upper die body 20 is arranged on the top of the middle die body 14. The initial forming area includes an L-shaped fold 16, a V-shaped fold 17, and a horizontal bearing platform arranged in sequence from the right front to the back. The L-shaped fold 16 is inclined, and the top of the L-shaped fold 16 and the horizontal bearing platform are coplanar. By using the fact that the top of the L-shaped fold 16 and the horizontal bearing platform are in the same plane, when the upper die body 20 moves down for forming, the plate is bent on both the left and right sides with the top of the L-shaped fold 16 as the boundary. The plate on the right side is first bent by the right part of the L-shaped fold 16 and then formed into a key structure through the V-shaped fold 17. After forming the key structure, the folded structure is initially formed.

[0030] It should be particularly noted here that since the angle of the L-shaped fold 16 is generally 90°, if it is not inclined, the initial forming process of the folded structure cannot be carried out. Once it is set as an inclined structure, due to the single set of molds used in this application and the short-distance retraction characteristic of the cylinder piston rod, the angle of the V-shaped fold 17 will be relatively small, generally only about 25°. This will make the processing and forming of the V-shaped fold 17 more difficult.

[0031] A lower die body 15 is also installed on the lower die base 10 directly below the installation part 131 of the connecting head 13. The output end of the second cylinder 12 is connected to the bottom of the lower die body 15. By the short-distance retraction of the piston rod of the second cylinder 12, the lower die body 15 can form the initially formed V-shaped structure 17 into the final form of the folded structure. The area between the lower die body 15 and the lower die base 10 is the secondary forming area.

[0032] The lower die body 15 includes a connecting part 151 connected to the output end of the second cylinder 12 and sliding relative to the lower die base 10, and a secondary forming pressure head 152 integrally connected to the connecting part 151. The bottom surface of the secondary forming pressure head 152 and the top surface of the lower die base 10 enclose the secondary forming area, and the top surface of the secondary forming pressure head 152 and the bottom surface of the connecting head 13 directly above the secondary forming pressure head 152 enclose a positioning area.

[0033] The surfaces of the middle die body 14, the lower die body 15, and the upper die body 20 are all provided with a Ti-xY wear-resistant alloy layer.

[0034] During use, first place the sheet on the positioning area of the horizontal plane formed by the L-shaped fold 16 and the horizontal base. The upper die body 20 moves downward to fold out the initial shape of the folded-back structure of the sheet. Subsequently, insert the horizontal section of the sheet into the positioning area between the lower die body 15 and the installation part 131, and position the right angle of the initial shape of the folded-back structure through the outer wall of the secondary forming pressure head 152. At the same time, the V-shaped structure of the initial shape of the folded-back structure is inside the secondary forming area. When placing a new sheet on the positioning area of the horizontal plane formed by the L-shaped fold 16 and the horizontal base, the upper die body 20 moves downward to form the initial shape of the folded-back structure of the new sheet. At the same time, the V-shaped structure located in the secondary forming area can be folded out into the final shape of the folded-back structure. Only one set of molds and two-step processes can complete the bending treatment of the key structure.

[0035] Example 2: The following improvements are made on the basis of the above example: The manufacturing process of the middle die body 14, the lower die body 15, and the upper die body 20, the processing steps are as follows: Nitriding and then oxidation treatment are carried out on the middle die body 14, the lower die body 15, and the upper die body 20 made of 42CrMo raw material steel. Prepare a deposition solution by mixing tetraethoxysilane, 28% ammonia water by mass fraction, pure water, and absolute ethanol in a ratio of 1:4:7:3. Place the heat-treated middle die body 14, lower die body 15, and upper die body 20 in 25 - 35 times the amount of the deposition solution, and carry out ultrasonic reaction at 45 - 60 Hz for 2 - 4 h. Then add 0.03 times the amount of nano-yttrium oxide of tetraethoxysilane, and carry out ultrasonic reaction at 45 - 60 Hz for 2 - 4 h. Take out and wash 2 times with 250 mL of pure water, wash 2 times with 180 mL of 95% ethanol, dry at 85 - 95 ° for 4 - 6 h, and then place it in a reactor. Evacuate to make the pressure reach 3.5 - 4.5 MPa, introduce 0.05 - 0.12 times the amount of gaseous titanium tetrachloride of tetraethoxysilane, raise the temperature of the reactor to 345 °, evacuate again to make the pressure reach 3.5 - 4.5 MPa, and then introduce a mixed reducing gas until the pressure reaches 75 - 95 MPa. Then, with the temperature of the middle die body 14, the lower die body 15, and the upper die body 20 being 1150 °, deposit for 5 - 8 h to obtain the Ti-xY wear-resistant alloy layer.

[0036] Example 3: The following improvements are made on the basis of the above example: the manufacturing process of the middle die body 14, the lower die body 15, and the upper die body 20, and the processing steps are as follows: Nitriding and then oxidation treatment are carried out on the middle die body 14, the lower die body 15, and the upper die body 20 made of 42CrMo as the raw material steel. Tetraethoxysilane, ammonia water with a mass fraction of 25% - 28%, pure water, and absolute ethanol are configured into a deposition solution according to the ratio of 1:5:8:4. The heat-treated middle die body 14, lower die body 15, and upper die body 20 are placed in 25 - 35 times the amount of the deposition solution, and ultrasonic reaction is carried out at 45 - 60 Hz for 2 - 4 h. Then, 0.05 times the amount of nano-yttrium oxide of tetraethoxysilane is added, and ultrasonic reaction is carried out at 45 - 60 Hz for 2 - 4 h. After taking out, it is washed 2 times with 250 mL of pure water and 2 times with 180 mL of 95% ethanol, dried at 85 - 95 ° for 4 - 6 h, and then placed in a reactor. The pressure is reduced to 3.5 - 4.5 MPa by vacuum pumping. Gaseous titanium tetrachloride of 0.05 - 0.12 times the amount of tetraethoxysilane is introduced, the temperature of the reactor rises to 340 °, the pressure is reduced to 3.5 - 4.5 MPa again by vacuum pumping, and then a mixed reducing gas is introduced until the pressure reaches 75 - 95 MPa. Then, with the temperature of the middle die body 14, lower die body 15, and upper die body 20 being about 1000 °, deposition is carried out for 7 h to obtain a Ti-xY wear-resistant alloy layer.

[0037] Example 4: The following improvements are made on the basis of the above example: the manufacturing process of the middle die body 14, the lower die body 15, and the upper die body 20, and the processing steps are as follows: Nitriding and then oxidation treatment are carried out on the middle die body 14, the lower die body 15, and the upper die body 20 made of 42CrMo as the raw material steel. Tetraethoxysilane, ammonia water with a mass fraction of 25% - 28%, pure water, and absolute ethanol are configured into a deposition solution according to the ratio of 1:4:8:3. The heat-treated middle die body 14, lower die body 15, and upper die body 20 are placed in 25 - 35 times the amount of the deposition solution, and ultrasonic reaction is carried out at 45 - 60 Hz for 2 - 4 h. Then, 0.04 times the amount of nano-yttrium oxide of tetraethoxysilane is added, and ultrasonic reaction is carried out at 45 - 60 Hz for 2 - 4 h. After taking out, it is washed 2 times with 250 mL of pure water and 2 times with 180 mL of 95% ethanol, dried at 85 - 95 ° for 4 - 6 h, and then placed in a reactor. The pressure is reduced to 3.5 - 4.5 MPa by vacuum pumping. Gaseous titanium tetrachloride of 0.05 - 0.12 times the amount of tetraethoxysilane is introduced, the temperature of the reactor rises to 350 °, the pressure is reduced to 3.5 - 4.5 MPa again by vacuum pumping, and then a mixed reducing gas is introduced until the pressure reaches 75 - 95 MPa. Then, with the temperature of the middle die body 14, lower die body 15, and upper die body 20 being about 950 °, deposition is carried out for 7 h to obtain a Ti-xY wear-resistant alloy layer.

[0038] Comparative Example 1: Only nitriding and then oxidation treatment are carried out.

[0039] Comparative Example 2: The middle die body 14, lower die body 15, and upper die body 20 made of 42CrMo as raw materials were subjected to nitriding and then oxidation treatment. Tetraethoxysilane, ammonia water with a mass fraction of 25% - 28%, pure water, and absolute ethanol were configured into a deposition solution in a ratio of 1:4 - 5:7 - 8:3 - 4. The heat-treated middle die body 14, lower die body 15, and upper die body 20 were placed in 25 - 35 times the amount of the deposition solution, and ultrasonic reaction was carried out at 45 - 60 Hz for 2 - 4 h. After taking out, they were washed 2 times with 250 mL of pure water and 2 times with 180 mL of 95% ethanol, and dried at 85 - 95 °C for 4 - 6 h. Subsequently, they were placed in a reactor, evacuated to a pressure of 3.5 - 4.5 MPa, and gaseous titanium tetrachloride in an amount of 0.05 - 0.12 times the amount of tetraethoxysilane was introduced. The temperature of the reactor was raised to 330 - 350 °C, and then evacuated again to a pressure of 3.5 - 4.5 MPa. Subsequently, a mixed reducing gas was introduced until the pressure reached 75 - 95 MPa. Then, with the temperature of the middle die body 14, lower die body 15, and upper die body 20 being 800 - 1200 °C, deposition was carried out for 7 h.

[0040] Comparative Example 3: The middle die body 14, lower die body 15, and upper die body 20 made of 42CrMo as raw materials were subjected to nitriding and then oxidation treatment. Tetraethoxysilane, ammonia water with a mass fraction of 25% - 28%, pure water, and absolute ethanol were configured into a deposition solution in a ratio of 1:4 - 5:7 - 8:3 - 4. The heat-treated middle die body 14, lower die body 15, and upper die body 20 were placed in 25 - 35 times the amount of the deposition solution, and ultrasonic reaction was carried out at 45 - 60 Hz for 2 - 4 h, and ultrasonic reaction was carried out at 45 - 60 Hz for 2 - 4 h. After taking out, they were washed 2 times with 250 mL of pure water and 2 times with 180 mL of 95% ethanol, and dried at 85 - 95 °C for 4 - 6 h. Subsequently, they were placed in a reactor, evacuated to a pressure of 3.5 - 4.5 MPa, and then a mixed reducing gas was introduced until the pressure reached 75 - 95 MPa. A titanium wire was introduced and heated to about 2000 °C, and then with the temperature of the middle die body 14, lower die body 15, and upper die body 20 being 800 - 1200 °C, deposition was carried out for 6 h.

[0041] The performance analysis results of the density and wear resistance of the Ti - xY wear-resistant alloy layer using Examples 2 to 4 and Comparative Examples 1 to 3 of the present invention are given as follows:

[0042]

[0043] The forming method of a multi-segment angular door frame uses the forming die as described in Example 1 and Example 2, and the forming process includes:

[0044] Step 1: Place the plate at the positioning area of the horizontal plane composed of the L-shaped folding angle 16 and the horizontal bearing platform;

[0045] Step 2: The upper die body 20 moves downward, and the initial shape of the folded-back structure is folded out from the sheet material through the forming area at the lower part of the upper die body 20 and the initial forming area of the middle die body 14. Then the upper die body 20 moves upward and returns to its original position;

[0046] Step 3: Take away the sheet material processed with the initial shape of the folded-back structure, insert the unprocessed horizontal section part into the positioning area between the lower die body 15 and the installation part 131, and position the right angle of the initial shape of the folded-back structure through the outer wall of the secondary forming pressure head 152. At the same time, the V-shaped structure of the initial shape of the folded-back structure is inside the secondary forming area;

[0047] Step 4: Place the new sheet material at the positioning area of the horizontal plane composed of the L-shaped fold angle 16 and the horizontal bearing platform. The upper die body 20 moves downward to form the initial shape of the folded-back structure on the new sheet material. At the same time, the V-shaped structure located in the secondary forming area can be folded into the final shape of the folded-back structure.

[0048] As described above, it is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. The substitution may be the substitution of part of the structure, device, method steps, or a complete technical solution. Any equivalent substitution or change made according to the technical solution and inventive concept of the present invention should be covered within the protection scope of the present invention.

Claims

1. A forming method for a multi-edged door frame, characterized in that This method uses a forming die, which includes a lower die base (10) and an upper die body (20). On the lower die base (10), a first cylinder (11) is installed at both ends and a second cylinder (12) is installed in the middle. A connector (13) is installed at the output end of the first cylinder (11). A middle die body (14) is installed at the top of the connector (13) by bolts. An initial forming area adapted to the forming area of the upper die body (20) is arranged on the top of the middle die body (14). A lower die body (15) is also installed on the lower die base (10) below the connector (13). The output end of the second cylinder (12) is connected to the bottom of the lower die body (15). The area between the lower die body (15) and the lower die base (10) is the secondary forming area. Wear-resistant Ti-xY alloy layers are provided on the surfaces of the middle die body (14), the lower die body (15), and the upper die body (20). The lower die body (15) has an inverted L-shaped structure. The lower die body (15) includes a connecting part (151) connected to the output end of the second cylinder (12) and sliding relative to the lower die base (10), and a secondary forming pressing head (152) integrally connected to the connecting part (151). The connecting part (151) is vertically arranged, the secondary forming pressing head (152) is horizontally arranged, the connecting part (151) and the secondary forming pressing head (152) are perpendicular to each other. The bottom surface of the secondary forming pressing head (152) and the top surface of the lower die base (10) enclose the secondary forming area. The top surface of the secondary forming pressing head (152) and the bottom surface of the connector (13) directly above the secondary forming pressing head (152) enclose a positioning area. The connector (13) includes an installation part (131) for installing the middle die body (14) by bolts, and a joint part (132) arranged at both ends of the bottom surface of the installation part (131) and fixedly connected to the output ends of the corresponding first cylinders (11). The initial forming area includes an L-shaped corner (16), a V-shaped corner (17), and a horizontal bearing platform arranged in sequence from the front right to the back. The L-shaped corner (16) is inclined, and the top of the L-shaped corner (16) is coplanar with the horizontal bearing platform. The forming method includes: Step 1: Place the sheet on the positioning area of the horizontal plane formed by the L-shaped corner (16) and the horizontal bearing platform. Step 2: The upper die body (20) moves downwards, and an initial shape of the folded-back structure is folded out from the sheet through the forming area at the lower part of the upper die body (20) and the initial forming area of the middle die body (14). The upper die body (20) moves upwards and resets. Step 3: Take away the sheet processed with the initial shape of the folded-back structure, insert the unprocessed horizontal section into the positioning area between the lower die body (15) and the installation part (131), and position the right angle of the initial shape of the folded-back structure through the outer wall of the secondary forming pressing head (152). At the same time, the V-shaped structure of the initial shape of the folded-back structure is inside the secondary forming area. Step 4: Place a new sheet on the positioning area of the horizontal plane formed by the L-shaped corner (16) and the horizontal bearing platform. The new sheet is formed into the initial shape of the folded-back structure by moving the upper die body (20) downwards. At the same time, the V-shaped structure located in the secondary forming area can be folded into the final shape of the folded-back structure.

2. The forming method of a multi-angled door frame according to claim 1, characterized in that The lower die base (10) is provided with mounting grooves (19) for mounting the first cylinder (11) and the second cylinder (12), and threaded holes are provided on the side of the mounting grooves (19).

3. The forming method of a multi-angled door frame according to claim 1, characterized in that, The processing methods of the middle die body (14), the lower die body (15), and the upper die body (20) are as follows: The middle die body (14), the lower die body (15), and the upper die body (20) made of 42CrMo as the raw material are subjected to nitriding and then oxidation treatment. A deposition solution is prepared by mixing tetraethoxysilane, ammonia water with a mass fraction of 25% - 28%, pure water, and absolute ethanol in a ratio of 1:4 - 5:7 - 8:3 - 4. The heat-treated middle die body (14), lower die body (15), and upper die body (20) are placed in 25 - 35 times the amount of the deposition solution, and ultrasonic reaction is carried out at 45 - 60 Hz for 2 - 4 h. Then, 0.02 - 0.08 times the amount of nano-yttrium oxide of tetraethoxysilane is added, and ultrasonic reaction is carried out at 45 - 60 Hz for 2 - 4 h. After taking out, it is washed 2 times with 250 mL of pure water and 2 times with 180 mL of 95% ethanol, and dried at 85 - 95 °C for 4 - 6 h. Subsequently, it is placed in a reactor, the vacuum is pumped to make the pressure reach 3.5 - 4.5 MPa, 0.05 - 0.12 times the amount of gaseous titanium tetrachloride of tetraethoxysilane is introduced, the temperature of the reactor rises to 330 - 350 °C, the vacuum is pumped again to make the pressure reach 3.5 - 4.5 MPa, and then a mixed reducing gas is introduced until the pressure reaches 75 - 95 MPa. Then, with the temperature of the middle die body (14), the lower die body (15), and the upper die body (20) being 800 - 1200 °C, deposition is carried out for 5 - 8 h.

4. A forming method of a multi-angular door frame according to claim 3, characterized in that, The mixed reducing gas includes one or more of hydrogen and silane in addition to methane.

Images