A multi-constraint step extrusion forming die for a large-sized anisotropic special-shaped box blank

Abstract

The present invention discloses a multi-constraint step extrusion forming die for a large-sized anisotropic and heteromorphic box blank, which comprises a first set of dies and a second set of dies. The first set of dies includes an upper die assembly and a lower die assembly. The upper die assembly includes an upper template, a punch, a large anvil, a small anvil and a handle. The lower die assembly includes a first female die, an internal stress ring, an external stress ring, a lower template and a ejector rod. The first female die is provided with an inner cavity for placing a blank, and the lower end of the large anvil extends into the middle and right parts of the inner cavity to extrude the blank. The second set of dies includes an upper template, a strip-shaped punch, an arched punch, a second female die, an upper stress ring and a lower stress ring. The second female die is provided with a receiving cavity and an arched cavity, and the lower ends of the strip-shaped punch and the arched punch respectively extend into the receiving cavity and the arched cavity to extrude the blank. The present invention is ingeniously designed. By changing the force-bearing positions of the blank through two sets of dies, the two-dimensional extrusion is transformed into three-dimensional extrusion, the pressure is reasonably applied, the forming load is effectively reduced, and a product meeting the service conditions is manufactured.

Description

Technical Field

[0001] The invention belongs to the technical field of plastic processing and forming of metal materials, and particularly relates to a multi-constraint step-by-step extrusion forming die for a large-sized anisotropic and heterotypic box blank. Background Art

[0002] With the continuous development of the industrial era, anisotropic boxes with the characteristics of light weight, integration, and complexity have gradually become the first choice for special equipment and large complex components. A box, such a component has the characteristics of complex structure and large size. Especially for a heterotypic box with anisotropic bosses, the forming direction of the bosses of this type of heterotypic box component is not in the same plane as the overall forming direction of the box. Therefore, the difficulty in forming this type of heterotypic box component lies in how to reasonably design the die structure to make the excess blank flow to the required part. The traditional box forming method usually uses a set of dies and only extrudes and forms once from one planar direction. When using the traditional die to form a box, the forming load is too large, which will damage the tissue uniformity of the box, the material utilization rate is low, and the mechanical properties are difficult to guarantee. Therefore, a die that can overcome the above defects is needed to meet the service conditions of this type of large-sized heterotypic box component. Summary of the Invention

[0003] The purpose of the invention is to provide a multi-constraint step-by-step extrusion forming die for a large-sized anisotropic and heterotypic box blank, which transforms the traditional two-dimensional extrusion into three-dimensional extrusion through two sets of dies, and utilizes the metal flow law to extrude and form the complex boss part multiple times and distributively, reduces the forming load, and improves the material utilization rate and production efficiency.

[0004] To achieve the above purpose, the solution of the invention is: a multi-constraint step-by-step extrusion forming die for a large-sized anisotropic and heterotypic box blank, comprising a first set of dies and a second set of dies;

[0005] The first set of molds includes an upper mold assembly and a lower mold assembly; the upper mold assembly includes an upper template, a punch, a large anvil, a small anvil, and a handle; the upper template is connected to the upper part structure of the press, the punch is fixed to the lower end of the upper template, the large anvil and the small anvil are installed below the punch, and the handle is connected to the large anvil; the lower mold assembly includes a first female mold, an internal stress ring, an external stress ring, a lower template, a top plate, and a ejector rod; the lower template is connected to the lower part of the press, the internal stress ring is fixed to the lower template, the first female mold and the top plate are installed inside the internal stress ring, and the first female mold is installed on the top plate; the first female mold is composed of multiple inserts, and the multiple inserts enclose a horizontal T-shaped inner cavity for placing the blank below the punch; the length of the large anvil is the same as the widths of the right and middle parts of the inner cavity. By moving the large anvil above the right and middle parts of the inner cavity through the handle, the lower end of the large anvil extends into the right or middle part of the inner cavity to extrude the blank; the size of the small anvil is the same as that of the left rear part of the inner cavity, so that the lower end of the small anvil extends into the left rear part of the inner cavity to extrude the blank; a knockout hole is opened in the middle of the bottom of the inner cavity, and the size is matched with the ejector rod. The external stress ring is interference-fitted and sleeved outside the internal stress ring.

[0006] The second set of molds includes an upper template, a strip-shaped punch, an arched punch, a second female mold, an upper stress ring, and a lower stress ring; the upper template is connected to the upper part of the press, and the strip-shaped punch and the arched punch are installed at the lower end of the lower template; a receiving cavity is provided in the second female mold for placing the blank extruded and formed by the first set of molds after being flipped 90°; the strip-shaped punch has the same size as the upper part of the receiving cavity, so that the lower end of the strip-shaped punch extends into the receiving cavity to extrude the blank; an arched cavity protrudes forward from the top of the receiving cavity, and the arched punch has the same size as the arched cavity, so that the lower end of the arched punch extends into the arched cavity to extrude the blank; the upper stress ring is sleeved on the upper part of the second female mold, and the lower stress ring is sleeved on the lower part of the second female mold.

[0007] Further, the first female mold is composed of five inserts, including one insert provided in each of the front, rear, and right parts, and two inserts arranged side by side in the front and rear of the left part. The five inserts enclose a horizontal T-shaped inner cavity. Removing the insert in the left front part enables the large anvil and the small anvil to press down the blank to form a T-shaped box body with a protrusion in the left front part.

[0008] Further, the handle is arranged on one side in the length direction of the large anvil and is always located above the first female mold, the internal stress ring, and the external stress ring.

[0009] Further, the upper template and the punch, and the lower template and the internal stress ring are fixedly connected by screws.

[0010] Further, the second set of molds extrudes and forms a T-shaped box body with a horizontal boss at the top.

[0011] Further, the second female die is an assembled female die, which is composed of a plurality of side plates and a bottom plate, and the extruded box body is taken out by disassembling the side plates.

[0012] Further, a fixed backing plate is arranged between the strip-shaped punch and the arched punch and the upper template, and the fixed backing plate is fixed to the upper template.

[0013] Further, a chute is opened at the lower end of the fixed backing plate, a guide rail matched with the chute is arranged at the top of the strip-shaped punch and the arched punch, and the guide rail is clamped with the chute to fix the strip-shaped punch and the arched punch to the fixed backing plate.

[0014] Further, the upper template and the fixed backing plate are fixedly connected by screws.

[0015] Further, the second set of dies further includes a support block, and the support block fills the lower part of the arched cavity to support the second female die.

[0016] After adopting the above scheme, the beneficial effects of the present invention are as follows:

[0017] The present invention designs two sets of dies, and two extrusion processes can be carried out through the two sets of dies, that is, the blank is extruded distributively from two plane directions, the flow law of the metal can be fully utilized, and a special-shaped box body with a boss is finally formed, improving the material utilization rate and production efficiency. The present invention is ingeniously designed, and is provided with two female dies that can respectively accommodate the blank to be placed from the horizontal and vertical directions. By changing the force application position of the blank, the two-dimensional extrusion is changed into three-dimensional extrusion, the pressure is applied reasonably, the forming load is effectively reduced, and the product that meets the service conditions is made with fewer steps and less pressure.

[0018] In addition, the present invention designs anvils with different sizes and strip-shaped punches and arched punches with different shapes to extrude the blank distributively, which can change the force application area of the blank, better control the metal stress state, equivalent strain, plastic deformation, tissue uniformity, etc., and ensure the smooth progress of the forming; at the same time, the two sets of dies of the present invention adopt the hot extrusion forming technology, compared with the cold extrusion technology, the extrusion pressure is greatly reduced, and while ensuring near-net forming, the optimal comprehensive mechanical properties of the material are also ensured. Description of the Drawings

[0019] Figure 1 It is a cross-sectional view of the first set of dies of the present invention;

[0020] Figure 2 It is a structural schematic diagram of the first set of dies of the present invention;

[0021] Figure 3 It is a top view of the lower die assembly of the present invention with the left front insert removed;

[0022] Figure 4Top view of the complete lower die assembly of the present invention;

[0023] Figure 5 Schematic structural view of the large cutting board in the first pressing state of the present invention;

[0024] Figure 6 Schematic structural view of the large cutting board in the second pressing state of the present invention;

[0025] Figure 7 Schematic structural view of the small cutting board in the pressing state of the present invention;

[0026] Figure 8 Schematic structural view of the blank formed in the first process step of the present invention;

[0027] Figure 9 Schematic structural view of the second set of dies of the present invention;

[0028] Figure 10 Exploded view of the parts of the second set of dies of the present invention;

[0029] Figure 11 Cross-sectional view of the second set of dies of the present invention;

[0030] Figure 12 Top view of the second female die of the present invention;

[0031] Figure 13 Top view of the strip-shaped punch of the present invention;

[0032] Figure 14 Top view of the arched punch of the present invention;

[0033] Figure 15 Schematic structural view of the finally formed box of the present invention.

[0034] Reference numeral description:

[0035] 1. Target formed box; 11. Boss; 2. First set of dies; 201. Upper template; 202. Punch; 203. Large cutting board; 204. Small cutting board; 205. Handle; 206. First female die; 2061. Insert; 207. Inner stress ring; 208. Outer stress ring; 209. Lower template; 210. Top plate; 211. Ejector rod; 212. Inner cavity; 213. Arc cavity; 3. Second set of dies; 31. Strip-shaped punch; 32. Arched punch; 321. Guide rail; 33. Second female die; 331. Side plate; 332. Bottom plate; 333. Accommodating cavity; 334. Arched cavity; 34. Upper stress ring; 35. Lower stress ring; 36. Fixed backing plate; 361. Chute; 37. Support block; 38. Repair block; 4. Blank; 41. Protrusion; 5. Screw. Detailed implementation manners

[0036] AsFigure 15 As shown, the target forming box body 1 of the present invention is in a "T" shape. When the box body is placed vertically, its top is provided with a horizontal boss 11 protruding forward. The boss 11 and the overall box body are not in the same plane. Therefore, the forming direction of the boss 11 and the overall forming direction of the box body are not in the same plane. The traditional extrusion method is single-side centralized forming or overall one-time forming, which will bring the problem of uneven forming load. Therefore, the difficulty in forming this special-shaped box body component lies in how to flow the redundant blank 4 to the required part, that is, the horizontal boss 11 part of the present invention, by reasonably designing the shape of the forging and the structure of the female die. It is necessary to reasonably control the flow direction of the blank 4 and the forming load. For this purpose, two sets of molds of the present invention are used, and through two extrusion processes, the special-shaped box body can be formed by distributed extrusion from two plane directions.

[0037] A multi-constraint step-by-step extrusion forming die for a large-scale anisotropic special-shaped box body blank provided by the present invention includes a first set of die 2 and a second set of die 3. As Figures 1 to 7 shown, the first set of die 2 includes an upper die assembly and a lower die assembly; the upper die assembly includes an upper template 201, a punch 202, a large anvil 203, a small anvil 204 and a handle 205. The upper template 201 is connected to the upper part structure of the press. The punch 202 is fixed at the lower end of the upper template 201. The large anvil 203 and the small anvil 204 are installed below the punch 202. The handle 205 is connected to the large anvil 203, and the large anvil 203 can be moved by driving the handle 205.

[0038] The lower die assembly includes a first female die 206, an internal stress ring 207, an external stress ring 208, a lower template 209, a top plate 210 and ejector rods 211. The lower template 209 is connected to the lower part of a press. The internal stress ring 207 is fixed on the lower template 209. The first female die 206 and the top plate 210 are installed inside the internal stress ring 207, and the first female die 206 is installed on the top plate 210. The first female die 206 is assembled by a plurality of detachable inserts 2061, including one insert 2061 provided at each of the front, rear and right parts, and two inserts 2061 arranged side by side in the front and rear of the left part. The five inserts 2061 enclose a transverse T-shaped inner cavity 212 for placing a blank 4 below a punch 202. The left front part of the T-shaped inner cavity 212 extends leftward to form an arc-shaped cavity 213, and the arc-shaped cavity 213 is filled with the insert 2061 at the left front part. The punch 202 can be in a T shape corresponding to the first female die 206 to achieve sufficient extrusion and reduce the material for making the punch 202. The length of the large anvil 203 is the same as the widths of the right and middle parts of the inner cavity 212, and the large anvil 203 can be moved above the right and middle parts of the inner cavity 212 through a handle 205, so that the lower end of the inner cavity 212 can extend into the right and middle parts of the inner cavity 212 to extrude the blank 4. The handle 205 is arranged on one side in the length direction of the large anvil 203. When moving the large anvil 203, the handle 205 is always located above the first female die 206, the internal stress ring 207 and the external stress ring 208 and does not affect the first female die 206, the internal stress ring 207 and the external stress ring 208. The size of the small anvil 204 is the same as that of the left rear part of the inner cavity 212, so that the lower end of the small anvil 204 can extend into the left rear part of the inner cavity 212 to extrude the blank 4. A top hole is opened in the middle of the bottom of the inner cavity 212, and the size is matched with the ejector rods 211. The external stress ring 208 is sleeved on the outside of the internal stress ring 207 by interference fit. The internal and external cooperation of the internal stress ring 207 and the external stress ring 208 further improves the die strength and prevents the blank 4 from being damaged due to stress overload during forming. The upper template 201 and the punch 202, and the lower template 209 and the internal stress ring 207 are fixedly connected by screws 5 to prevent the punch 202 from sliding relative to the upper template 201 and the internal stress ring 207 from sliding relative to the lower template 209.

[0039] Such as Figures 9 to 14As shown in the figure, the second set of dies 3 includes an upper template 201, a strip-shaped punch 202, an arched punch 202, a second female die 33, an upper stress ring 34, and a lower stress ring 35. The upper template 201 is connected to the upper part of the press; the strip-shaped punch 202 and the arched punch 202 are installed at the lower end of the lower template 209. A fixed backing plate 36 can be arranged between the strip-shaped punch 202 and the arched punch 202 and the upper template 201, and is fixed to the upper template 201 through the fixed backing plate 36. The fixed backing plate 36 is fixed at the lower end of the lower template 209, and the strip-shaped punch 202 and the arched punch 202 are installed at the lower end of the fixed backing plate 36; the second female die 33 is an assembled female die composed of a plurality of side plates 331 and a bottom plate 332. The side plates 331 and the bottom plate 332 enclose a receiving cavity 333 for the blank 4 extruded and formed by the first set of dies 2 to be placed vertically after being turned 90°. The size of the strip-shaped punch 202 is the same as that of the receiving cavity 333, and the strip-shaped punch 202 can extend into the receiving cavity 333 to extrude the blank 4; a arched cavity 334 protrudes forward at the top of the receiving cavity 333. The size of the arched punch 202 is the same as that of the arched cavity 334, and the arched punch 202 can extend into the arched cavity 334 to extrude the blank 4; to save the production material of the second female die 33, the lower part of the arched cavity 334 can be set to be hollow, and a support block 37 is filled under the arched cavity 334 to support the second female die 33, ensure the stability of the second female die 33 during extrusion, make the extrusion more sufficient, and can also reduce the cost; the upper stress ring 34 is sleeved on the upper part of the second female die 33, and the lower stress ring 35 is sleeved on the lower part of the second female die 33. The upper stress ring 34 and the lower stress ring 35 can enhance the strength of the second female die 33 and prevent the second set of dies 3 from cracking due to stress overload.

[0040] The upper template 201 and the fixed backing plate 36 are fixedly connected by screws 5 to prevent the fixed backing plate 36 from sliding relative to the upper template 201; the strip-shaped punch 202 and the arched punch 202 are quickly installed at the lower end of the upper template 201 through the fixed backing plate 36. Specifically, a chute 361 is opened at the lower end of the fixed backing plate 36, and guide rails 321 matching the chute 361 are arranged at the tops of the strip-shaped punch 202 and the arched punch 202. The guide rails 321 are clamped with the chute 361 to fix the strip-shaped punch 202 and the arched punch 202 to the fixed backing plate 36, which is convenient for disassembling and assembling the strip-shaped punch 202 and the arched punch 202. The disassembly and assembly are simple and fast, saving production time and realizing rapid production; when the size of the fixed backing plate 36 is not enough, supplementary blocks 38 can be fixed on both sides of the fixed backing plate 36 to increase the extrusion pressure and prevent the strip-shaped punch 202 and the arched punch 202 from sliding.

[0041] The specific steps of the multi-constraint step-by-step extrusion forming method for the large-scale anisotropic and heterogeneous box blank involved in the present invention are as follows:

[0042] S1 Upsetting forming: The bar stock is formed into a blank 4 through the upsetting process;

[0043] S2 Prepare the first set of dies 2: Assemble the internal stress ring 207, external stress ring 208, lower template 209 and ejector rod 211 according to the above assembly relationship, and install the assembled above components on the lower working table of the press, so that the lower template 209 is connected to the lower part structure of the press; Connect and fix the upper template 201 and the punch 202, and install the installed upper template 201 and punch 202 on the upper working table of the press, so that the upper template 201 is connected to the upper part structure of the press; Preheat the first female die 206, large anvil 203, small anvil 204 and top plate 210. After the preheating is completed, place the first female die 206 and the top plate 210 into the internal stress ring 207;

[0044] S3 First process forming: Put the preheated blank 4 into the inner cavity 212, install the large anvil 203 below the punch 202, and the large anvil 203 presses down twice in sequence, including:

[0045] The first press down: As Figure 5 shown, install the large anvil 203 above the right part of the inner cavity 212. The descent of the press drives the punch 202 to move downward, so that the large anvil 203 presses down the right part of the inner cavity 212, and stop squeezing after the blank 4 completely fills the right part of the inner cavity 212;

[0046] The second press down: As Figure 6 shown, the press drives the punch 202 to rise, remove the insert 2061 at the left front part of the first female die 206, so that the arc cavity 213 at the left front part of the T-shaped inner cavity 212 is exposed. Use the handle 205 to move the large anvil 203 above the middle part of the inner cavity 212, and lower the press to make the large anvil 203 press down the middle part of the inner cavity 212, so that the excess blank 4 moves to the left front of the inner cavity 212, so that the blank 4 flows into the arc cavity 213 to form a horizontal protrusion 41, and make the height of the blank 4 in the middle part of the inner cavity 212 equal to the height of the blank 4 in the right part, so that the blank 4 completely fills the middle and right parts of the inner cavity 212;

[0047] If after two press downs, the heights of the middle and right parts of the blank 4 are not level, the large anvil 203 can be moved to the uneven part by using the handle 205 and continue to press down until the blank 4 is extruded flat;

[0048] After the large anvil 203 finishes pressing down, raise the press and remove the large anvil 203, and install the small anvil 204 below the punch 202, as Figure 7As shown, the length of the small anvil 204 is the same as the width of the left rear part of the inner cavity 212. The lower end of the small anvil 204 extends into the left rear part of the inner cavity 212. The press drives the punch 202 to descend, pressing down the small anvil 204 on the left rear part of the inner cavity 212, making the height of the blank 4 in the left rear part of the inner cavity 212 flush with the height of the blanks 4 in the middle and right parts. At the same time, the excess blank 4 is extruded towards the arc cavity 213 to form a vertical protrusion 41, that is, the blank 4 is preliminarily extruded and formed. After the extrusion is completed, the press drives the punch 202 to rise away from the formed blank 4, removes the small anvil 204, the ejector rod 211 rises to eject the formed blank 4, the first female die 206 and the top plate 210, removes the insert 2061 of the first female die 206, and takes out the formed blank 4; as Figure 8 shown, the formed blank 4 is a T-shaped box body with irregular protrusions 41 protruding horizontally to the left and vertically upwards at the left front part;

[0049] S4 Prepare the second set of dies 3: Connect and fix the upper template 201 and the fixed backing plate 36, and install the upper template 201 and the fixed backing plate 36 on the upper working table of the press, so that the upper template 201 is connected to the upper part structure of the press; Preheat the second female die 33, the strip-shaped punch 202, and the arched punch 202. After the preheating is completed, assemble the second female die 33, the support block 37, the upper stress ring 34, and the lower stress ring 35 according to the above assembly relationship;

[0050] S5 Second process forming: After preheating the blank 4 formed in the first process, turn it clockwise by 90°, make its protrusion 41 face upwards and place it into the accommodation cavity 333. Install the strip-shaped punch 202 at the lower end of the fixed backing plate 36. The press descends to drive the strip-shaped punch 202 to press down the top of the blank 4, so that the blank 4 fills the accommodation cavity 333, and presses the excess blank 4 in the upper part of the accommodation cavity 333 into the arched cavity 334; Then raise the press, install the arched punch 202 at the lower end of the fixed backing plate 36, and the press drives the strip-shaped punch 202 and the arched punch 202 to continue pressing down. Wait until the blank 4 completely fills the second female die 33 to obtain the formed box body, and stop the extrusion; The press drives the strip-shaped punch 202 and the arched punch 202 to rise away from the formed box body, removes the support block 37 and the stress ring, then removes the side plate 331 of the second female die 33, and takes out the formed box body. This formed box body is the special-shaped box body with a horizontal convex platform 11 protruding forward at the top finally manufactured by the present invention.

[0051] The above method uses a distributed extrusion method for forming. Compared with the traditional single extrusion forming method, multiple-step extrusion can effectively reduce the forming load. By using anvils of different sizes and strip-shaped punches 202 and arched punches 202 with different shapes to distributively extrude the blank 4, the stress area of the blank 4 is changed, which can better control the metal stress state, equivalent strain, plastic deformation, and tissue uniformity, etc., ensuring the smooth progress of forming. At the same time, the present invention adopts a hot extrusion forming technology. Compared with the cold extrusion technology, the extrusion pressure is greatly reduced, while ensuring near-net forming, the optimal comprehensive mechanical properties of the material are also ensured.

[0052] The present invention makes full use of the fluidity of the metal. In the second extrusion process of the large anvil 203 in step S3, by changing the number of inserts 2061, the protrusion 41 can be formed, and then the boss 11 part can be formed by extrusion with the strip-shaped punch 202 and the arched punch 202 in step S5.

[0053] The traditional forming method uses ordinary plastic forming technology, which will result in a large number of required processes for forming due to the very complex structure of the part, being time-consuming and laborious and difficult to machine a satisfactory structure. Compared with the traditional forming method, the present invention uses two sets of molds and, through two extrusion processes, distributively extrudes the blank 4 from two planar directions, converting two-dimensional extrusion into three-dimensional extrusion to form a special-shaped box body with a boss 11. The present invention changes the stress position of the blank 4, reasonably applies pressure, and manufactures a product that meets the service conditions with fewer steps and less pressure.

[0054] The above are only the preferred embodiments of the present invention and do not limit the design of this case. All equivalent changes made according to the key design of this case fall within the protection scope of this case.

Claims

1. A multi-constraint step extrusion forming die for a large-sized anisotropic and heterogeneous box blank, Characterized in that: It includes a first set of dies and a second set of dies; The first set of dies includes an upper die assembly and a lower die assembly; the upper die assembly includes an upper template, a punch, a large anvil, a small anvil and a handle; the upper template is connected to the upper part structure of the press, the punch is fixed at the lower end of the upper template, the large anvil and the small anvil are installed below the punch, and the handle is connected to the large anvil; the lower die assembly includes a first female die, an internal stress ring, an external stress ring, a lower template, a top plate and a ejector rod; the lower template is connected to the lower part of the press, the internal stress ring is fixed on the lower template, the first female die and the top plate are installed inside the internal stress ring, and the first female die is installed on the top plate; the first female die is composed of multiple inserts, and the multiple inserts form a horizontal T-shaped inner cavity for placing the blank below the punch; the length of the large anvil is the same as the width of the right and middle parts of the inner cavity, and the large anvil is moved above the right and middle parts of the inner cavity through the handle, so that the lower end of the large anvil extends into the right or middle part of the inner cavity to extrude the blank; the size of the small anvil is the same as that of the left rear part of the inner cavity, so that the lower end of the small anvil extends into the left rear part of the inner cavity to extrude the blank; a top hole is opened in the middle of the bottom of the inner cavity, and the size is matched with the ejector rod, and the external stress ring is interference-fitted and sleeved outside the internal stress ring; The second set of dies includes an upper template, a strip-shaped punch, an arched punch, a second female die, an upper stress ring and a lower stress ring; the upper template is connected to the upper part of the press, and the strip-shaped punch and the arched punch are installed at the lower end of the lower template; a receiving cavity for placing the blank extruded by the first set of dies after being turned 90° is arranged in the second female die; the strip-shaped punch has the same size as the upper part of the receiving cavity, so that the lower end of the strip-shaped punch extends into the receiving cavity to extrude the blank; an arched cavity protrudes forward from the top of the receiving cavity, and the arched punch has the same size as the arched cavity, so that the lower end of the arched punch extends into the arched cavity to extrude the blank; the upper stress ring is sleeved on the upper part of the second female die, and the lower stress ring is sleeved on the lower part of the second female die.

2. A multi-constraint step extrusion forming die for a large-sized anisotropic and heterogeneous box blank according to claim 1, Characterized in that: The first female die is composed of five inserts, including one insert provided in each of the front, rear and right parts, and two inserts arranged side by side in the front and rear of the left part. The five inserts form a horizontal T-shaped inner cavity. Removing the insert in the left front part enables the large anvil and the small anvil to press down the blank to form a T-shaped box with a protrusion in the left front part.

3. A multi-constraint step extrusion forming die for a large-sized anisotropic and heterogeneous box blank according to claim 1, Characterized in that: The handle is arranged on one side in the length direction of the large anvil and is always located above the first female die, the internal stress ring and the external stress ring.

4. A multi-constraint step extrusion forming die for a large-sized anisotropic and heterogeneous box blank according to claim 1, Characterized in that: The upper template and the punch, and the lower template and the internal stress ring are fixedly connected by screws.

5. A multi-constraint step-by-step extrusion forming die for a large-sized anisotropic special-shaped box blank as claimed in claim 1, characterized in that: The second set of dies extrude and form a T-shaped box with a horizontal boss at the top.

6. A multi-constraint step-by-step extrusion forming die for a large-sized anisotropic special-shaped box blank as claimed in claim 5, characterized in that: The second female die is an assembled female die, which is composed of a plurality of side plates and a bottom plate, and the extruded and formed box is taken out by disassembling the side plates.

7. A multi-constraint step-by-step extrusion forming die for a large-sized anisotropic special-shaped box blank as claimed in claim 1, characterized in that: A fixed backing plate is arranged between the strip-shaped punch and the arched punch and the upper template, and is fixed to the upper template through the fixed backing plate.

8. A multi-constraint step-by-step extrusion forming die for a large-sized anisotropic special-shaped box blank as claimed in claim 7, characterized in that: A chute is opened at the lower end of the fixed backing plate, guide rails matching the chute are arranged at the tops of the strip-shaped punch and the arched punch, and the guide rails are clamped with the chute to fix the strip-shaped punch and the arched punch to the fixed backing plate.

9. A multi-constraint step-by-step extrusion forming die for a large-sized anisotropic special-shaped box blank as claimed in claim 1, characterized in that: The upper template and the fixed backing plate are fixedly connected by screws.

10. A multi-constraint step-by-step extrusion forming die for a large-sized anisotropic special-shaped box blank as claimed in claim 1, characterized in that: The second set of dies further includes a support block, and the support block fills the lower part of the arched cavity to support the second female die.

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