A preparation mold for preventing aluminum cans from cracking during forming

Abstract

An aluminum can forming anti - cracking preparation die, including a third - order die for preliminary trimming of the stamping object, a fourth - order die for square drawing forming of the stamping object, and a fifth - order die for forming and diameter expansion of the stamping object. Among them, when the third - order die is stamping, the upper shear die can cut off the edge of the stamping object; when the fourth - order die is stamping, the bottom of the stamping object is between the upper pressing die and the lower forming die, and the periphery of the stamping object is between the lower forming die and the square - drawing upper clamping die; when the fifth - order die is stamping, the bottom of the stamping object is between the stamping flange and the stamping groove, the peripheral surface of the stamping object abuts against the forming concave pattern, and the top of the stamping object is between the lower diameter - expansion die and the diameter - expansion upper clamping die. By punching the edge of the stamping object before the square - drawing process, the fine cracks that may cause the tank body to rupture are removed in advance, reducing the defective rate; and the square - drawing and plastic - rib diameter - expansion processes are processed step by step, reducing the pressure during stamping and avoiding irreversible damage to the material and thus rupture.

Description

Technical Field

[0001] The present invention relates to the technical field of molds, in particular to an anti-cracking preparation mold for forming aluminum cans. Background Art

[0002] Metal cans are categorized as two-piece and three-piece cans. The three-piece can's body consists of a top cover, body, and bottom cover, and the manufacturing process is complex, including rounding, welding, re-coating, drying, flanging, gluing and drying the bottom cover, and sealing. A two-piece can's body, consisting of a top cover and body, is formed in one piece by stamping and stretching. Its manufacturing process is relatively simple: the can body undergoes cupping and one or more stretching steps, followed by bottom forming, ribbed walls, and expansion, before trimming.

[0003] The two-piece can forming process is commonly used for the forming of iron cans. If the two-piece can forming process is used for aluminum cans, it is easy for the sheet material to break during the stamping and stretching process, resulting in defective or waste products.

[0004] The reason is that aluminum's tensile strength is much lower than iron, making it prone to fine cracks on its edges during the stamping and stretching process. These cracks can then break during subsequent stretching processes. This is especially true for aluminum cans that require multiple stretching cycles, leading to lower yield rates. Therefore, it's necessary to optimize the molds used to form aluminum two-piece cans to improve yield rates. Summary of the Invention

[0005] The purpose of the present invention is to provide an anti-fracture preparation mold for aluminum cans, which solves the problems of easy breakage and low yield of the above-mentioned aluminum can bodies during the stamping process.

[0006] To achieve the above-mentioned object, the present invention provides an aluminum can forming anti-cracking preparation die, comprising a first sequence die for punching a blank, a second sequence die for initial stretching of the punch, a third sequence die for initial trimming of the punch, a fourth sequence die for square forming of the punch, a fifth sequence die for expanding the diameter of the punch, and a sixth sequence die for trimming the punch.

[0007] The third die includes a trimming upper die, an upper shearing die and a trimming lower die. The trimming upper die performs a reciprocating lifting motion along the vertical direction of the trimming lower die. A placement space is provided in the trimming upper die for placing a punched object. The upper shearing die is fixed to the lower end of the trimming upper die, and the upper shearing die is sleeved outside the trimming lower die.

[0008] When the trimming upper die is in a descending state, the upper shearing die cuts off the edge of the punched object;

[0009] The fourth sequence die includes a square drawing upper clamping die, an upper pressing die, a square drawing lower clamping die, and a lower forming die. The square drawing upper clamping die reciprocates vertically along the square drawing lower clamping die. The upper pressing die is inside the square drawing upper clamping die. The lower forming die is arranged inside the square drawing lower clamping die and directly below the upper pressing die.

[0010] When the square drawing upper clamping die is in the descending state, the bottom of the stamping object is between the upper pressing die and the lower forming die, and the periphery of the stamping object is between the lower forming die and the square drawing upper clamping die.

[0011] The fifth sequence die includes an expanding diameter upper clamping die, an upper forming die, an expanding diameter lower clamping die, a lower expanding die, and a rib forming die. The expanding diameter upper clamping die is directly above the expanding diameter lower clamping die and reciprocates vertically along the expanding diameter lower clamping die. The upper forming die is inside the expanding diameter upper clamping die. One end of the lower expanding die is fixed inside the expanding diameter lower clamping die. The rib forming die is fixedly connected to the other end of the lower expanding die. The diagonal length of the expanding diameter lower clamping die is greater than that of the rib forming die. A stamping flange is provided on one side of the upper forming die close to the rib forming die. A stamping groove corresponding to the stamping flange is provided on one side of the rib forming die close to the upper forming die. And forming concave lines are provided around the rib forming die.

[0012] When the expanding diameter upper clamping die is in the descending state, the bottom of the stamping object is between the stamping flange and the stamping groove, the peripheral surface of the stamping object abuts against the forming concave lines, and the top of the stamping object is between the lower expanding die and the expanding diameter upper clamping die.

[0013] Preferably, the trimming upper die includes a trimming upper die base, an upper shear pad die, and an upper shear pressing die. One end of the upper shear pad die is fixedly connected to the trimming upper die base. The upper shear pressing die is fixedly connected to the other end of the upper shear pad die. A fixing groove is provided at the end of the upper shear pressing die away from the upper shear pad die. A fixing convex edge is provided at one end of the upper shear die. The fixing convex edge is fitted and connected with the fixing groove.

[0014] Preferably, the trimming upper die further includes a demolding cylinder and an upper stripping die. The demolding cylinder passes through the trimming upper die base and the upper shear pad die and is fixedly connected to the upper stripping die. The upper stripping die is inside the upper shear pad die.

[0015] Preferably, the trimming upper die further includes a lower cutting knife. The lower cutting knife is arranged on the outer periphery of the trimming lower die, and the end close to the upper shear die is a blade. The lower cutting knife is within the moving range of the upper shear die. The lower cutting knife is used to cut off the waste after the initial trimming of the stamping object.

[0016] Preferably, the drawing square lower clamping die includes a lower die base, a lower cylinder, an inner guide column and a lower clamping stripping die. The lower cylinder is fixedly connected to the side of the lower die base away from the lower forming die. One end of the inner guide column passes through the lower die base and is connected to the lower cylinder, and the other end is fixedly connected to the lower clamping stripping die. The lower clamping stripping die is sleeved outside the lower forming die, and an air port is provided at the lower end of the lower cylinder.

[0017] A step groove is provided in the upper clamping die of the drawing square, and the outer side of the upper end of the lower clamping stripping die corresponds to the step groove sleeve;

[0018] The structure of the diameter-expanding lower clamping die is the same as that of the square-pulling lower clamping die.

[0019] Preferably, a limiting flange is provided on one side of the lower stripping die that is sleeved with the lower forming die, and a limiting groove is provided on the outer periphery of the lower portion of the lower forming die, and the limiting flange slides on the limiting groove.

[0020] Preferably, the drawing lower clamping die also includes an outer guide column and a lower outer stripping die, one end of the outer guide column passes through the lower die base and is connected to the lower cylinder, and the other end is fixedly connected to the lower outer stripping die, and the lower outer stripping die is sleeved outside the lower clamping stripping die.

[0021] Preferably, the square drawing lower clamping die also includes a lower outer cover die, the lower outer cover die is fixedly connected to the lower die base, the lower outer cover die is sleeved on the outside of the lower outer stripping die, a limiting convex edge is provided on the inner side of the lower end of the lower outer cover die, and a positioning groove is provided on the outer periphery of the lower outer stripping die, and the positioning groove is abutted against the limiting convex edge.

[0022] Preferably, the upper clamping die of the drawing square includes an upper die base and an upper cylinder, the upper cylinder is fixedly connected to the upper die base, an air port is provided at one end of the upper cylinder away from the upper die base, the output end of the upper cylinder passes through the upper die base and is fixedly connected to the upper pressure die, and a step groove is provided at one end of the upper die base close to the lower clamping die of the drawing square.

[0023] Beneficial effects of the present invention:

[0024] By punching the edges of the stamped material before squared-out, we preemptively remove any minor cracks that could cause can rupture, improving the success rate of aluminum can molding. Separating the squared-out and plastic rib expansion processes reduces pressure during the stamping process, ensuring that the pressure in each step remains within the aluminum material's tolerance and preventing irreversible damage. By optimizing the mold structure and ensuring the coordinated operation of components, we improve the overall structural stability of the aluminum can molding process, reduce the defective rate, and achieve excellent economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art.

[0026] Figure 1 It is the overall process schematic diagram of the present invention.

[0027] Figure 2 It is the connection schematic diagram when the third-stage die of the present invention is closed.

[0028] Figure 3 It is the connection schematic diagram when the third-stage die of the present invention is opened.

[0029] Figure 4 is Figure 3 the enlarged view of part A in

[0030] Figure 5 It is the connection schematic diagram when the fourth-stage die of the present invention is closed.

[0031] Figure 6 It is the connection schematic diagram when the fourth-stage die of the present invention is opened.

[0032] Figure 7 is Figure 5 the enlarged view of part B in

[0033] Figure 8 is Figure 6 the enlarged view of part C in

[0034] Figure 9 It is the connection schematic diagram when the fifth-stage die of the present invention is closed.

[0035] Figure 10 It is the connection schematic diagram when the fifth-stage die of the present invention is opened.

[0036] Figure 11 is Figure 10 the enlarged view of part D in

[0037] In the figure: trimming upper die 10; trimming upper die base 100; upper shear pad die 101; upper shear pressing die 102; fixing groove 1020; demolding cylinder 103; upper stripping die 104; lower cutting knife 105; upper shear die 11; fixing convex edge 110; trimming lower die 12; square drawing upper clamping die 20; step groove 201; upper die base 202; upper cylinder 203; upper pressing die 21; square drawing lower clamping die 22; lower die base 220; lower cylinder 221; inner guide pillar 222; lower clamping stripping die 223; limiting flange 2231; outer guide pillar 224; lower outer stripping die 225; positioning groove 2251; lower outer cover die 226; limiting convex edge 2261; lower forming die 23; limiting groove 231; diameter-expanding upper clamping die 30; upper forming die 31; stamping flange 310; diameter-expanding lower clamping die 32; lower diameter-expanding die 34; rib forming die 35; stamping groove 350; forming concave pattern 351. Specific embodiments

[0038] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present invention, but should not be construed as a limitation to the present invention.

[0039] In the traditional square iron can forming process, it includes blanking, initial stretching, square drawing forming and diameter expansion, and finally trimming operation. When attempting to directly apply aluminum materials to the stamping process originally designed for iron cans, during the square drawing forming and diameter expansion process of aluminum cans, the phenomenon of frequent cracking of the can body occurs, resulting in a relatively high production defective rate. The main reasons are as follows: First, in the blanking link, after the blank is punched, although its edge seems flat, there are actually fine and imperceptible uneven cracks to the naked eye. During the subsequent stamping forming process, when the can body is subjected to the tensile force, these tiny cracks will be further aggravated and then extend and expand, ultimately leading to the cracking of the can body; Second, in terms of material properties, the yield strength of iron is significantly greater than that of aluminum. In the traditional process of simultaneous square drawing, plastic ribbing and diameter expansion, for aluminum cans, the required stamping pressure strength is extremely easy to exceed the yield strength of aluminum, resulting in irreversible damage to the material.

[0040] Based on the above situation, the present invention proposes a preparation mold for preventing cracking in the forming of aluminum cans, as Figure 1As shown in the figure, it includes a first-stage die for blanking of the stamping object, a second-stage die for initial stretching of the stamping object, a third-stage die for initial trimming of the stamping object, a fourth-stage die for forming the stamping object into a square shape, a fifth-stage die for forming and expanding the diameter of the stamping object, and a sixth-stage die for forming and trimming the stamping object. Before the square-forming process of the present invention, the edge of the stamping object is first cut by the third-stage die, the purpose of which is to cut off in advance the cracks that are prone to force extension during the subsequent stretching process at the edge, effectively avoiding the problem of can body rupture caused by the extension of the edge cracks. At the same time, by processing the square-forming and plastic rib diameter expansion step by step, the pressure during the aluminum can stamping process can be further reduced, making the pressure in each step within the range that the aluminum material can withstand, avoiding irreversible damage to the material, thereby improving the success rate of aluminum can forming and reducing the defective rate.

[0041] As Figure 2 shown in the figure, the third-stage die includes an upper trimming die 10, an upper cutting die 11 and a lower trimming die 12. The upper trimming die 10 reciprocates up and down along the vertical direction of the lower trimming die 12. A placement space is provided inside the upper trimming die 10 for placing the stamping object. The upper cutting die 11 is fixed to the lower end of the upper trimming die 10 and is sleeved outside the lower trimming die 12. When the upper trimming die 10 is in the descending state, the upper cutting die 11 cuts off the edge of the stamping object. When the upper trimming die 10 moves down, the placement space inside it can well avoid the can body part of the stamping object, preventing accidental damage to the can body during the process of punching the edge. As the upper trimming die 10 moves down, when it moves to be pressed against the lower trimming die 12, the upper cutting die 11 will cut off the edge of the stamping object. At the same time, the upper trimming die 10 and the lower trimming die 12 will tightly clamp the remaining edge of the stamping object. By cutting the edge with the upper cutting die 11 and clamping the stamping object by the upper and lower trimming dies, the present invention can make the cut more smooth, reduce stress concentration, and thus effectively reduce the occurrence of cracks.

[0042] In the actual operation process, the stamping object undergoes the previous process treatments. For example, after the initial stretching by the second-stage die, the punching sheet is stretched into an elliptical can body, and this initial stretching process lays the foundation shape for the subsequent forming. Then, the edge of the elliptical can body is cut by the third-stage die, which can effectively reduce the cracks at the edge of the elliptical can body, improve the integrity of the edge of the stamping object, and contribute to the smooth progress of the subsequent forming process.

[0043] Then, this die performs the next step of square stretching on the already cut can body. As Figure 5As shown, the fourth sequence die includes a square upper clamping die 20, an upper pressing die 21, a square lower clamping die 22 and a lower forming die 23. The square upper clamping die 20 performs reciprocating lifting and lowering motions along the vertical direction of the square lower clamping die, providing a key movement basis for the subsequent forming operation of the stamping object; the upper pressing die 21 is inside the square upper clamping die 20, and the lower forming die 23 is arranged inside the square lower clamping die 22 and is directly below the upper pressing die 21. When the square upper clamping die 20 is in a descending state, the bottom of the stamping object is between the upper pressing die 21 and the lower forming die 23, and the periphery of the stamping object is between the lower forming die 23 and the square upper clamping die 20, forming an orderly stamping object forming space. The present invention can transform the stamping object from an elliptical can body formed by the second sequence die to a square can body by further utilizing the cooperation of the above-mentioned components in the fourth sequence die on the basis of the processing of the third sequence die. Furthermore, during the can body conversion and molding process, due to the large change in curvature at the corners of the square can body, the material is subjected to relatively large tensile and deformation forces at the corners during the molding process, which can easily cause cracking. In the present invention, the upper and lower clamping dies 20 and 22 of the square can body are used to press the corners of the protruding can body. This pressing can, to a certain extent, resist the tendency of the material to separate due to stretching and deformation at the corners, change the stress state of the material at the corners, and make it more evenly bear stress from all directions. This improves the overall structural stability of the can body during the molding process and effectively prevents the can body from cracking at the corners.

[0044] After the square stretching, the stamped object is further formed by the fifth die. Figure 9 As shown, the fifth sequence mold of the present invention includes an expanding upper clamping die 30, an upper forming die 31, an expanding lower clamping die 32, a lower expanding die 34 and a rib forming die 35. The expanding upper clamping die 30 is located directly above the expanding lower clamping die 32 and performs reciprocating lifting and lowering motions along the vertical direction of the expanding lower clamping die 32. The upper forming die 31 is located inside the expanding upper clamping die 30. One end of the lower expanding die 34 is fixed in the expanding lower clamping die 32. The rib forming die 35 is fixedly connected to the other end of the lower expanding die 34. The diagonal length of the expanding lower clamping die 32 is greater than that of the rib forming die 35. A stamping flange 310 is provided on the side of the upper forming die 31 close to the rib forming die 35, and a stamping groove 250 corresponding to the stamping flange 310 is provided on the side of the rib forming die 35 close to the upper forming die 31, and forming grooves 351 are provided around the rib forming die 35. When the expanding upper clamping die 30 is in a descending state, the bottom of the stamping object is between the stamping flange 310 and the stamping groove 250, the peripheral surface of the stamping object is in contact with the forming groove 351, and the top of the stamping object is between the lower expanding die 34 and the pulling upper clamping die 20.

[0045] During the manufacturing process of the tank body, the dimensional accuracy of the tank opening will have an important impact on subsequent use, such as encapsulation, connection with other components, etc. In the present invention, the lower diameter-expanding die 34 can further accurately expand the tank opening of the stamping object under the cooperation of the upper diameter-expanding clamping die 30 and the lower diameter-expanding clamping die 32, so as to meet the overall design requirements of the tank body. When the forming concave lines 351 around the rib forming die 35 abut against the peripheral surface of the stamping object, reinforcing ribs will be formed around the stamping object. Secondly, when the tank body is subjected to external pressure, impact or internal pressure changes, the reinforcing ribs can effectively disperse stress, avoid local deformation or rupture of the tank body, and thus improve the overall quality and durability of the tank body. When the upper diameter-expanding clamping die 30 is in the descending state, the bottom of the stamping object is located between the stamping flange 310 and the stamping groove 250, the peripheral surface abuts against the forming concave lines 351, and the top is located between the lower diameter-expanding die 34 and the upper drawing clamping die 20, ensuring the accurate action of each component on the stamping object during the stamping process. On this basis, the upper forming die 31 and the rib forming die 35 perform a concave stamping operation on the bottom of the stamping object through the cooperation of the stamping flange 310 and the stamping groove 250. The bottom concave forming, the tank opening diameter expansion and the formation operation of the peripheral reinforcing ribs cooperate with each other to jointly complete the formation of the overall shape of the tank body.

[0046] Specifically, referring to Figures 2 - 4 , the trimming upper die 10 of the present invention includes a trimming upper die base 100, an upper shearing pad die 101 and an upper shearing pressing die 102. One end of the upper shearing pad die 101 is fixedly connected to the trimming upper die base 100, the upper shearing pressing die 102 is fixedly connected to the other end of the upper shearing pad die 101, a fixing groove 1020 is provided at the end of the upper shearing pressing die 102 away from the upper shearing pad die 101, and a fixing flange 110 is provided at one end of the upper shearing die 11. The fixing flange 110 is fitted and connected with the fixing groove 1020. During the trimming process, the upper shearing die 11 and the upper shearing pressing die 102 adopt a fixing method of fitting connection between the fixing flange 110 and the fixing groove 1020. The detachable connection method is convenient for processing and assembly during the manufacturing process, can improve production efficiency, reduce processing difficulty and cost. In addition, this fitting connection method can play a buffering and fine-tuning role to a certain extent while ensuring connection stability. During the trimming operation, due to the fitting connection between the upper shearing die 11 and the upper shearing pressing die 102, when subjected to external force impact or minor adjustment is required, there can be a certain relative displacement space between the fixing flange 110 and the fixing groove 1020. This characteristic helps to reduce the stress concentration and component damage caused by rigid connection, and improves the service life and reliability of the entire trimming upper die 10 structure.

[0047] In addition, since the initial stretch of the stamping is oval, when its edge is punched, the edge waste is also a complete oval ring. Therefore, the problem of discharging the waste needs to be considered. Thus, the trimming upper die 10 of the present invention further includes a lower cutting knife 105. The lower cutting knife 105 is disposed on the outer periphery of the trimming lower die 12, and the end close to the upper shearing die 11 is the blade. The lower cutting knife 105 is within the moving range of the upper shearing die 11, and the lower cutting knife 105 is used to cut off the waste after the initial trimming of the stamping. The lower cutting knife 105 of the present invention can cut the waste in half while the edge of the stamping is being punched, avoiding the situation where the waste may cause blockage or hinder the discharging in the die due to irregular shape or large size. At the same time, the lower cutting knife 105 is disposed below, which can better utilize the relatively abundant space below, making the structure of the die more compact and reasonable, reducing unnecessary space waste, and enabling the waste to be smoothly discharged along the preset discharging channel (not shown in the figure) below the die after being cut by the lower cutting knife 105, reducing the residue and accumulation of the waste inside the die, and improving the discharging efficiency.

[0048] Further, referring to Figure 2 , the trimming upper die 10 further includes a demolding cylinder 103 and an upper stripping die 104. The demolding cylinder 103 passes through the trimming upper die base 100 and the upper shearing pad die 101 and is fixedly connected to the upper stripping die 104. The upper stripping die 104 is within the upper shearing pad die 101. One end of the upper stripping die 104 of the present invention extending into the demolding cylinder 103 forms a sealed sliding connection with the lower cylinder 221, enabling the upper stripping die 104 to perform a smooth linear motion under the push of the lower cylinder 221. The other end of the upper stripping die 104 is within the upper shearing pad die 101 and abuts against the stamping. During the stamping operation, the stamping is prone to displacement under the action of various external forces, and the abutment of the pressing block against the stamping can effectively limit the movement of the stamping and ensure the accuracy of the stamping process. In addition, after the stamping is completed, as the trimming upper die 10 moves upward, the upper stripping die 104 also moves accordingly. Due to the abutting relationship between the upper stripping die 104 and the stamping, under the push of the demolding cylinder 103, the upper stripping die 104 can push out the stamping. This pushing action effectively prevents the occurrence of material jamming.

[0049] Referring to Figure 2 , Figure 3 , the working principle of the third-stage die of the present invention: When the trimming upper die 10 descends, the internal placement space avoids the tank body part of the stamping, and the upper stripping die 104 abuts against the bottom of the stamping. As the trimming upper die 10 continues to move downward and is pressed against the trimming lower die 12, the upper shearing die 11 cuts off the edge of the stamping; at the same time, the trimming upper die 10 and the trimming lower die 12 clamp the remaining edge of the stamping, and the lower cutting knife 105 cuts the waste into two sections and discharges it. After the punching is completed, as the trimming upper die 10 moves upward, the demolding cylinder 103 drives the upper stripping die 104 to push the stamping away from the placement space.

[0050] Furthermore, referring to Figure 5 and Figure 6 , the lower clamping and stripping die 22 of the present invention includes a lower die base 220, a lower air cylinder 221, inner guide columns 222 and a lower clamping and stripping die 223. The lower air cylinder 221 is fixedly connected to one side of the lower die base 220 away from the lower forming die 23. One end of the inner guide column 222 passes through the lower die base 220 and is connected to the lower air cylinder 221, and the other end is fixedly connected to the lower clamping and stripping die 223. The lower clamping and stripping die 223 is sleeved outside the lower forming die 23, and an air port is provided at the lower end of the lower air cylinder 221. By inputting gas into the air port at the lower end of the lower air cylinder 221, the lower air cylinder 221 generates power and drives the inner guide column 222 to perform a linear motion. Since the inner guide column 222 is fixedly connected to the lower clamping and stripping die 223, the lower clamping and stripping die 223 is pushed to perform a linear motion for material stripping, realizing automatic demolding by using the power of the lower air cylinder 221, greatly improving the demolding efficiency and reliability, and effectively preventing the occurrence of material jamming of the stamping object. During the stamping process, the stamping object is subjected to a large pressure. If its position is unstable, uneven deformation may occur under the action of the pressure, resulting in cracking.

[0051] Referring to Figure 7 , a stepped groove 201 is provided inside the upper clamping die 20 of the present invention, and the outer side of the upper end of the lower clamping and stripping die 223 corresponds to the stepped groove 201. The edge of the stamping object is clamped by the stepped groove 201 of the upper clamping die 20 and the upper end of the lower clamping and stripping die 223, making the force on the stamping object more uniform during the stamping process. The pressure during stamping can be more evenly distributed to the entire stamping object through the clamped edge, reducing the situation of local stress concentration, and thus effectively preventing the risk of cracking of the stamping object due to uneven force.

[0052] As Figure 9 and Figure 10 shown, the structure of the diameter-expanding lower clamping die 32 is the same as that of the lower clamping die 22 of the square drawing, thereby reducing the design complexity of the die, improving the production efficiency and reducing the production cost.

[0053] In addition, referring to Figure 5 , a limiting flange 2231 is provided on one side of the lower clamping and stripping die 223 of the present invention that is sleeved with the lower forming die 23, and a limiting groove is provided on the outer periphery of the lower part of the lower forming die 23. The limiting flange 2231 slides on the limiting groove. During the opening and closing of the die, the limiting groove and the limiting flange 2231 can play a guiding role, making the movement of the die smoother and more stable, reducing the wear and damage of the die, and preventing the die from shifting or loosening during the working process, ensuring the stability and reliability of the die.

[0054] Furthermore, referring to Figure 6, the lower clamping die 22 of the square also includes an outer guide pillar 224 and a lower outer stripping die 225. One end of the outer guide pillar 224 passes through the lower die base 220 and is connected to the lower air cylinder 221, and the other end is fixedly connected to the lower outer stripping die 225. The lower outer stripping die 225 is sleeved outside the lower clamping and stripping die 223. During the stamping process, the power of the lower air cylinder 221 is transmitted to the lower outer stripping die 225 through the outer guide pillar 224, causing it to descend and abut against the end face of the upper clamping die 20 of the square, further providing positioning for the downward pressing of the upper clamping die 20 of the square, preventing its position from shifting, avoiding damage to the stamping object due to excessive local punching pressure, and ensuring the stamping forming effect. When the stamping is completed, the lower outer stripping die 225 rises under the drive of the lower air cylinder 221. Since the lower outer stripping die 225 is sleeved outside the lower clamping and stripping die 223, the two cooperate with each other during the movement process to jointly perform the stripping process on the stamping object, and can more thoroughly and smoothly strip the stamping object from the mold, effectively improving the success rate of demoulding and reducing the possibility of the stamping object remaining in the mold.

[0055] Furthermore, refer to Figure 6 , Figure 8, the lower clamping die 22 of the present invention further includes a lower outer cover die 226. The lower outer cover die 226 is fixedly connected to the lower die base 220. The lower outer cover die 226 is sleeved outside the lower outer stripping die 225. A limiting convex edge 2261 is provided on the inner side of the lower end of the lower outer cover die 226. A positioning groove 2251 is provided on the outer periphery of the lower outer stripping die 225. The positioning groove 2251 is in abutting connection with the limiting convex edge 2261. During the demolding process, the lower outer cover die 226 plays a role in restricting and guiding the movement of the lower outer stripping die 225 through the abutting relationship between the limiting convex edge 2261 and the positioning groove 2251 of the lower outer stripping die 225, ensuring that the lower outer stripping die 225 moves along a predetermined trajectory. When the lower outer stripping die 225 needs to move upward for demolding, the abutting of the limiting convex edge 2261 and the positioning groove 2251 can prevent the lower outer stripping die 225 from shifting, ensuring the smooth progress of the demolding action. In addition, in the working environment of the lower clamping die 22 of the present invention, the lower outer stripping die 225 is easily affected by external factors. For example, the intrusion of impurities such as dust and debris may affect its normal operation and reduce its service life. The setting of the lower outer cover die 226 is like a protective cover, which can effectively block external impurities from entering the lower outer stripping die 225 and its internal structure area. This helps to keep the lower outer stripping die 225 clean, reduce damage caused by factors such as impurity friction and corrosion, and thus improve the reliability and stability of the entire structure of the lower clamping die 22. Moreover, during the stamping process, the stability of the working environment around the lower outer stripping die 225 has an important impact on its working effect. The fixed connection between the lower outer cover die 226 and the lower die base 220 enhances the rigidity of the entire structure. This increase in rigidity helps to reduce the adverse effects caused by vibration during the stamping process. For example, excessive vibration may cause inaccurate positioning of the lower outer stripping die 225, thereby affecting the demolding effect. The presence of the lower outer cover die 226 can effectively suppress this vibration, provide a more stable working environment for the lower outer stripping die 225, and improve the accuracy of the stamping and demolding operations.

[0056] In addition, referring to Figure 6, the upper clamping die 20 of the present invention includes an upper die base 202 and an upper air cylinder 203. The upper air cylinder 203 is fixedly connected to the upper die base 202. One end of the upper air cylinder 203 away from the upper die base 202 is provided with an air port. The output end of the upper air cylinder 203 passes through the upper die base 202 and is fixedly connected to the upper pressing die 21. The step groove 201 is arranged at one end of the upper die base 202 close to the lower clamping die 22 for drawing. In the structure of the upper clamping die 20 for drawing, the upper die base 202 serves as a basic component and is fixedly connected to the upper air cylinder 203 to ensure the connection stability between the two. And an air port is arranged at one end of the upper air cylinder 203 away from the upper die base 202, which is the inlet for the upper air cylinder 203 to obtain the power source (such as compressed air). The output end of the upper air cylinder 203 passes through the upper die base 202 and is fixedly connected to the upper pressing die 21. This connection method enables the upper air cylinder 203 to directly transmit the power to the upper pressing die 21. In the present invention, the structure of the upper air cylinder 203 driving the upper pressing die 21 can provide precise stripping power by adjusting parameters such as the gas pressure and flow rate entering the air port, ensuring that the upper pressing die 21 performs the stripping operation on the material according to the predetermined trajectory and strength, and can be flexibly adjusted according to the actual stripping requirements (such as the thickness of the punched material, the stripping stroke, etc.).

[0057] As Figure 9 , Figure 10 shown, except for not having the convex patterns for stamping, the structure of the upper clamping die 30 for diameter expansion is the same as that of the upper clamping die 20 for drawing, and it can also reduce the design complexity of the die and lower the production cost.

[0058] Referring to Figure 5 , Figure 6 , the working principle of the fourth - stage die of the present invention: When the upper clamping die 20 for drawing descends, the bottom of the stamping object is between the upper pressing die 21 and the lower forming die 23, and the periphery is between the lower forming die 23 and the upper clamping die 20 for drawing. When forming the corners of the tank body, the upper clamping die 20 for drawing and the lower clamping die 22 for drawing tightly press the corners. And with the completion of stamping, the upper clamping die 20 for drawing moves upward. The lower clamping stripping die 223 and the lower outer stripping die 225 push up the stamping object under the action of the lower air cylinder 221, and at the same time, the upper pressing die pushes out the stamping object under the action of the upper air cylinder 203 to complete the die stripping.

[0059] Referring to Figures 9 - 11, The working principle of the fifth sequence die of the present invention: When the expanding upper clamping die 30 descends, the bottom of the stamping object is located between the stamping flange 310 and the stamping groove 250, the circumferential surface abuts against the forming concave pattern 351, and the top is located between the lower expanding die 34 and the pulling square upper clamping die 20. At this time, the lower expanding die 34 accurately expands the can mouth under the cooperation of the expanding upper clamping die 30 and the expanding lower clamping die 32, and the forming concave patterns 351 around the rib forming die 35 form reinforcing ribs on the circumferential surface of the stamping object; meanwhile, the upper forming die 31 and the rib forming die 35 perform a concave stamping operation on the bottom of the stamping object through the cooperation of the stamping flange 310 and the stamping groove 250. After the stamping is completed, the stamping object is unloaded, referring to the unloading method of the fourth sequence die, which will not be elaborated here.

[0060] The above disclosure is only one or more preferred embodiments of the present application, and cannot be used to limit the scope of rights of the present application. Those of ordinary skill in the art can understand all or part of the processes of implementing the above embodiments, and the equivalent changes made according to the claims of the present application still fall within the scope covered by the present application.

Claims

1. A mold for forming and preventing cracking of aluminum cans, characterized in that: The die comprises a first die for punching blanks, a second die for initial stretching of the punch, a third die for initial trimming of the punch, a fourth die for square forming of the punch, a fifth die for expanding the diameter of the punch, and a sixth die for trimming the punch. The third sequence die comprises a trimming upper die (10), an upper shearing die (11) and a trimming lower die (12). The trimming upper die (10) performs a reciprocating lifting motion along the vertical direction of the trimming lower die (12). A placement space is provided in the trimming upper die (10) for placing a punched object. The upper shearing die (11) is fixed to the lower end of the trimming upper die (10). The upper shearing die (11) is sleeved outside the trimming lower die (12). When the trimming upper die (10) is in a descending state, the upper shearing die (11) cuts off the edge of the punched object; The fourth sequence mold comprises a square upper clamping mold (20), an upper pressing mold (21), a square lower clamping mold (22) and a lower forming mold (23), wherein the square upper clamping mold (20) performs a reciprocating lifting motion along the vertical direction of the square lower clamping mold (22), the upper pressing mold (21) is located inside the square upper clamping mold (20), and the lower forming mold (23) is arranged inside the square lower clamping mold (22) and is located directly below the upper pressing mold (21). When the upper clamping die (20) is in a descending state, the bottom of the punched object is located between the upper pressing die (21) and the lower forming die (23), and the periphery of the punched object is located between the lower forming die (23) and the upper clamping die (20); The fifth sequence die comprises an upper diameter expansion die (30), an upper forming die (31), a lower diameter expansion die (32), a lower diameter expansion die (34) and a rib forming die (35), wherein the upper diameter expansion die (30) is located directly above the lower diameter expansion die (32) and performs reciprocating lifting and lowering motions along the vertical direction of the lower diameter expansion die (32), the upper forming die (31) is located inside the upper diameter expansion die (30), one end of the lower diameter expansion die (34) is fixed inside the lower diameter expansion die (32), and the rib forming die (35) is fixedly connected to the other end of the lower diameter expansion die (34), the diagonal length of the lower diameter expansion clamping die (32) is greater than that of the rib forming die (35), a stamping flange (310) is provided on the side of the upper forming die (31) close to the rib forming die (35), a stamping groove (350) corresponding to the stamping flange (310) is provided on the side of the rib forming die (35) close to the upper forming die (31), and forming grooves (351) are provided around the rib forming die (35). When the expansion upper clamping die (30) is in a descending state, the bottom of the punch is between the punching flange (310) and the punching groove (350), the peripheral surface of the punch abuts against the forming groove (351), and the top of the punch is between the lower expansion die (34) and the expansion upper clamping die (30); The trimming upper die (10) comprises a trimming upper die base (100), an upper notch pad die (101) and an upper notch pressing die (102), one end of the upper notch pad die (101) is fixedly connected to the trimming upper die base (100), the upper notch pressing die (102) is fixedly connected to the other end of the upper notch pad die (101), the end of the upper notch pressing die (102) away from the upper notch pad die (101) is provided with a fixing groove (1020), and one end of the upper notch die (11) is provided with a fixing ridge (110), and the fixing ridge (110) is engaged with the fixing groove (1020).

2. The anti-cracking mold for aluminum can molding according to claim 1, characterized in that: The trimming upper die (10) further comprises a demoulding cylinder (103) and an upper stripping die (104); the demoulding cylinder (103) passes through the trimming upper die base (100) and the upper notch pad die (101) and is fixedly connected to the upper stripping die (104); the upper stripping die (104) is located within the upper notch pad die (101).

3. The anti-cracking mold for aluminum can molding according to claim 1, characterized in that: The trimming upper die (10) further comprises a lower cutter (105), which is arranged on the outer periphery of the trimming lower die (12) and has a blade at one end close to the upper shearing die (11). The lower cutter (105) is within the moving range of the upper shearing die (11), and is used to cut off waste material after the initial trimming of the punched object.

4. The anti-cracking mold for aluminum can molding according to claim 1, characterized in that: The drawing square lower clamping die (22) comprises a lower die base (220), a lower cylinder (221), an inner guide column (222) and a lower clamping stripping die (223). The lower cylinder (221) is fixedly connected to the side of the lower die base (220) away from the lower forming die (23). One end of the inner guide column (222) passes through the lower die base (220) and is connected to the lower cylinder (221), and the other end is fixedly connected to the lower clamping stripping die (223). The lower clamping stripping die (223) is arranged outside the lower forming die (23). An air port is provided at the lower end of the lower cylinder (221). The upper clamping die (20) is provided with a step groove (201), and the outer side of the upper end of the lower clamping stripping die (223) is sleeved with the step groove (201); The structure of the diameter-expanding lower clamping die (32) is the same as that of the square-pulling lower clamping die (22).

5. The anti-cracking mold for aluminum can molding according to claim 4, characterized in that: A limiting flange (2231) is provided on one side of the lower stripping die (223) sleeved with the lower forming die (23), and a limiting groove (231) is provided on the outer periphery of the lower portion of the lower forming die (23), and the limiting flange (2231) slides on the limiting groove (231).

6. The anti-cracking mold for aluminum can molding according to claim 4, characterized in that: The drawing square lower clamping die (22) further includes an outer guide column (224) and a lower outer stripping die (225), one end of the outer guide column (224) passes through the lower die base (220) and is connected to the lower cylinder (221), and the other end is fixedly connected to the lower outer stripping die (225), and the lower outer stripping die (225) is sleeved outside the lower clamping stripping die (223).

7. The anti-cracking mold for aluminum can molding according to claim 6, characterized in that: The drawing square lower clamping die (22) further comprises a lower outer cover die (226), the lower outer cover die (226) is fixedly connected to the lower die base (220), the lower outer cover die (226) is sleeved outside the lower outer stripping die (225), a limiting convex edge (2261) is provided on the inner side of the lower end of the lower outer cover die (226), and a positioning groove (2251) is provided on the outer periphery of the lower outer stripping die (225), and the positioning groove (2251) is abutted against the limiting convex edge (2261).

8. The anti-cracking mold for aluminum can molding according to claim 4, characterized in that: The upper clamping die (20) for drawing square includes an upper die base (202) and an upper cylinder (203), wherein the upper cylinder (203) is fixedly connected to the upper die base (202), and an air port is provided at one end of the upper cylinder (203) away from the upper die base (202), and an output end of the upper cylinder (203) passes through the upper die base (202) and is fixedly connected to the upper pressing die (21), and a step groove (201) is provided at one end of the upper die base (202) close to the lower clamping die (22).

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