CN114669683A - Forming process and forming die for high-tensile straight-wall square tank - Google Patents

Abstract

The invention discloses a forming process and a forming die of a high-tensile straight-wall square can, wherein the stretching process comprises four procedures of blanking and punching a cup, stretch forming, flaring forming and trimming, and the forming die comprises a cup punching die for slicing and blanking a can body material and primary stretching, a stretch forming die for secondary stretching of the can body after the primary stretching, a flaring forming die for final forming of the can body after the secondary stretching and a trimming die for shearing a formed can body flanging.

Description

Forming process and forming die for high-tensile straight-wall square tank

Technical Field

The invention relates to the technical field of cold stamping processing, in particular to a forming process and a forming die for a high-tensile straight-wall square tank.

Background

The metal package is used as a fast food for food, and the market development space is huge. The two cans are integrally formed by punching and drawing, and are more and more popular in the market due to the unique advantages and characteristics of the cans. On the other hand, with the push of the concept of light weight of products, the thickness of the material for forming the food can is continuously reduced, and on the premise of ensuring that various basic performance parameters of the food can meet requirements, the hardness of the material is inevitably required to be enhanced. However, in the case of a deep-drawn two-piece food can, the ratio of the height to the diameter (or the median of the width of the cross section of the body) is greater than 1, and since the degree of deformation is large during the forming, it is not possible to form the can by drawing at one time as can be seen from the theory of drawing deformation. At present, the commonly adopted drawing technical process is to design the tank wall into a cone shape, and adopt a blank pressing forming drawing process with a flange edge to gradually reduce the tank diameter until the tank is finally drawn and formed. When the mode is used for high (deep) stretching, the material is easy to crack due to the fact that the material is large in stretching deformation degree and blocked in material flowing, and the stretching coefficient is gradually reduced by a plurality of stations. Taking three-time stretch forming of the most common conical tank (a non-high stretching tank, the ratio of the height to the diameter (or the intermediate value of the width of the cross section of the main body) is usually less than 0.6) as an example, when a large-to-small stretching method is adopted, because the local blank holding area is limited, and the forming of the third process has a suspended area due to the fact that the straight-surface conversion conical surface forming exists, the tank body is easy to crack in the third process, and the unstable wrinkling phenomenon is generated at the transition fillet of the tank body. Meanwhile, the production process is complex, the requirement on production equipment is high, the number of equipment procedures is large, and the production investment and the cost are high. Particularly, for a high-tensile straight-wall square tank, the tank body is easy to crack or unstably wrinkle in the stretching process due to the larger deformation degree. Particularly, when a high-strength and low-elongation thinned material is used for stretch forming, how to solve the problem by using a new stretch forming process is a technical problem to be solved urgently by technical personnel in the field of canned food, and a solution to the problem is not searched in the existing published documents.

Disclosure of Invention

The invention aims to solve the problems that the tank body is easy to break, the transition fillet of the tank body generates instability wrinkling phenomenon and the existing multi-station step-by-step reduction stamping process has more steps, the requirement on production equipment is high and the production investment and cost are high in the stamping process of the high-tensile straight-wall square tank in the prior art, and provides a forming process and a forming die of the high-tensile straight-wall square tank.

The invention adopts a specific technical scheme to solve the technical problems that a forming process of a high-tensile straight-wall square tank comprises the following steps:

a. the blanking and punching process is used for slicing and blanking the tank body materials and simultaneously stretching the tank body materials to form a cup body, the height of the cup body is 40% -60% of the height of a finished tank body, the cup body is cylindrical and is of a straight-wall structure, the diameter of the cup body is 1.8-2.2 times of the width of the middle cross section of the finished tank body, the cross section area of an opening of the cup body is the same as the middle cross section area of the cup body, and the cup body which completes the blanking and punching process is conveyed to the stretching and forming process through a tank body clamping and conveying device.

b. And a stretching forming process, wherein the limiting type is adopted to reduce the forming, the cross section area of the cup body after the blanking and cup punching process is reduced, the second stretching of the stretching height is increased, the ratio of the height of the stretching tank body after the stretching forming process to the width of the cross section is more than 1, the tank wall reinforcing ribs and the tank bottom are sunk into the plane to be formed while stretching is carried out, and the stretching tank body is conveyed to the flaring forming process through a tank body clamping and conveying device after the stretching forming process is completed.

c. And the flaring forming process adopts envelope forming, the material is formed at the downward envelope forming opening part, the influence of the stretching process on the tank opening part is reduced, the forming of the tank flaring part matched with the easy-open cover and the flanging fillet is completed, and the flared tank body completing the flaring forming process is conveyed to the edge cutting process through the tank body clamping and conveying device.

d. And a trimming process, namely cutting redundant materials of the flanging to enable the flanging to meet the matching requirement of the double-seaming tank cover, and moving the finished tank body which is subjected to the trimming process out of the trimming process through the tank body clamping and conveying device.

The forming process aims at the forming of the high-tensile straight-wall two-piece square can, the straight-wall punching cup without the outward flanging is adopted, then the limiting type reduction forming is carried out, the main part of the can body is basically completed, the third procedure adopts the enveloping forming, the material is formed by enveloping the forming opening part downwards, the influence of the stretching process on the can opening part is reduced, the dimensional stability is ensured, and the instability and wrinkling in the stretching process are avoided. The limited stretch forming is carried out after the cup punching, the enveloping forming of the opening part is favorable for controlling the material flow trend, and finally a straight-wall tank body is formed, wherein the straight wall refers to that the main part (excluding the flaring part of the tank opening) of the tank body is vertical to the plane of the tank bottom, so that the instability wrinkling and the common cracking problems in the forming process of the high-stretch two-piece tank are solved, on the premise of ensuring various performance requirements of the conical tank, the problems of tank body cracking and transition fillet instability wrinkling are effectively solved, the production process can be simplified, the equipment quantity is reduced, and the production investment and the cost are reduced.

A forming die of a high-tensile straight-wall square tank is suitable for the forming process of the high-tensile straight-wall square tank, and comprises the following steps:

the cup punching die is applied to a blanking cup punching process and is used for slicing and blanking a tank body material and forming a cup body through first stretching, the cup body after the first stretching is cylindrical, the wall of the cup body is of a straight wall structure, the height of the cup body is 40% -60% of the height of a finished tank body, the diameter of the cup body after the first stretching is 1.8-2.2 times of the width of the middle cross section of the finished tank body, the middle cross section area of the cup body after the first stretching is 85% -90% of the middle cross section area of the finished tank body, and the cross section area of an opening of the cup body after the first stretching is the same as the middle cross section area of the cup body. During the stretching forming process of the tank body material, the sheet material is changed into a three-dimensional box-shaped member, and the edge parts of the male die and the female die have horizontal tensile force and vertical extrusion force, so that the tank body material has a wrinkling tendency. When the edge-holding force of the mold is insufficient, the edges of the can body material are liable to be unstably wrinkled, and this phenomenon is often improved by increasing the edge-holding force. However, in order to reduce the production cost and improve the product competitiveness, manufacturers use high-hardness and low-ductility can body materials, and if the traditional flat edge pressing mode is adopted, the workpiece is easy to stretch and break by continuously improving the edge pressing force. The cup making process of the invention changes the mode of the wide flanging square cup body which is usually adopted in the past square can forming, the large-diameter straight-wall round can-shaped cup body without the flanging is adopted, the structure without the flanging relieves the limitation of blank holder stretching on the material flowability, greatly increases the material flowability, the large-diameter circular structure ensures that the tank body material in the cup punching stage is uniformly stressed on the tank wall, the problem of instability wrinkling or tensile fracture is not easy to occur, the molded cup body is fully expanded, the deformation of the subsequent stretching process is relatively less, therefore, the problems that the tank body material has the tendency of wrinkling, and the tank body material is easy to unstably wrinkle and stretch rupture due to the fact that the horizontal tensile force and the vertical extrusion force exist at the edge parts of the male die and the female die in the punching cup stretching process of the traditional square tank are greatly reduced.

The stretching forming die is applied to a stretching forming process and used for carrying out secondary stretching on the cup body after primary stretching to form a stretching tank body, and comprises primary forming of sinking planes on a tank wall reinforcing rib and a tank bottom and forming a flanging at a tank opening, wherein the stretching tank body is in a cuboid shape, the tank wall of the stretching tank body is of a straight wall structure, the height of the stretching tank body after secondary stretching is 70% -90% of the height of a finished tank body, the middle cross-sectional area of the stretching tank body after secondary stretching is 90% -95% of the middle cross-sectional area of the finished tank body, and the flanging width of the stretching tank body after secondary stretching is 10-15 times of the flanging width of the finished tank body.

The flaring forming die is applied to a flaring forming process and used for carrying out third-time stretching forming on the stretched tank body after the second stretching to form a formed tank body, and comprises the steps of final forming of tank wall reinforcing ribs and tank bottom reinforcing ribs, forming flaring and flanging fillet forming at an opening end of the tank body, wherein the height of the formed tank body after the third stretching is the height of the finished tank body, the middle cross-sectional area of the formed tank body is the middle cross-sectional area of the finished tank body, and the flanging width of the formed tank body after the third stretching is 3-6 times of the flanging width of the finished tank body.

And the trimming die is used for trimming the flanging part at the opening of the formed tank body, and the width and the fillet structure of the flanging of the finished tank body after trimming meet the matching requirements of the double-seaming tank cover.

Preferably, the punching cup die is a blanking forming compound die and comprises a punching cup lower die plate used for supporting, a punching cup lower cylinder arranged in the punching cup lower die plate, a piston of the punching cup cylinder is connected with a punching cup ejection ring through a punching cup ejection rod, a punching cup lower die seat used for fixing a punching cup lower die core, a punching cup fixing seat used for fixing a punching cup female die, a punching cup upper die core connected with a punching cup upper cylinder is arranged in the center of the punching cup convex-concave die, a punching cup unloading ring is arranged on the periphery of the punching cup convex-concave die, the punching cup unloading ring is fixed with a punching cup upper die seat used for fixing a punching cup upper die through a spring, and the punching cup upper die seat is arranged on the punching cup upper die plate. The lower punching cup template is used for supporting the whole punching cup die and is a bottom plate of the punching cup die, the lower punching cup die holder is used for fixing the lower punching cup die, the upper punching cup template is a bottom plate for fixing the upper punching cup die, and the upper punching cup die holder is used for fixing the upper punching cup die; the cup punching cylinder provides a blank pressing force, and the blank pressing force, the cup punching ejector rod, the cup punching ejector ring and the like form a material pressing device together to realize the blank pressing function; the punching cup fixing seat mainly has the main functions of fixing a punching cup female die, adjusting the height of a blanking plane of the punching cup female die and providing a forming space, the punching cup female die is matched with the punching cup male and female die, under the action of a power source, a sheet material is punched, the blanking function is realized, and a punching cup discharging ring pushes out waste materials so that the waste material ring is not sleeved on the punching cup male and female die; after the blanking action is finished, the punching cup punch-die continues to move downwards under the action of a power source and interacts with the punching cup lower die core to stretch the sheet material for forming, the punching cup upper die continues to move upwards to the upper dead point under the action of power, the punching cup lower die recovers, and the one-time punching process is finished.

Preferably, the stretching forming die comprises a stretching male die and a stretching female die which are arranged on a stretching lower die base, a stretching positioning ring is formed on the periphery of the upper end of the stretching male die and the stretching female die, a stretching lower die core and a stretching piston rod connected with the stretching lower die core are arranged in the center of the stretching male die and the stretching female die, a stretching ejection ring and a stretching ejection rod are arranged in the stretching fixing ring, the stretching fixing ring is arranged on a stretching upper die base, and a stretching die core is arranged in the center of the stretching ejection ring. The cross section area is reduced on the basis of a cup body in a first cup punching process, secondary stretching is carried out on the stretch height, and after the stretching is finished, the forming of a tank wall reinforcing rib part and a tank bottom sinking plane is required to be finished, so that the forming key process of the high-stretch tank is realized. The invention eliminates the unstable wrinkling phenomenon of the transition fillet forming through the blank pressing, simultaneously considers the problem of station conversion positioning between the die procedures, and adopts the stretching forming mode of increasing the height of the tank body gradually. According to the stretching principle, the technical scheme can effectively solve the instability wrinkling problem of the tank body under the conditions of increasing the transition fillet of the female die, reducing the surface roughness of the die, increasing the lubrication of materials and slowing down the stretching speed, and simultaneously ensures various performance requirements of the tank body.

Preferably, the flaring forming die is used for the flaring forming process of the tank body and comprises a flaring lower die holder and a flaring punch-die arranged on the flaring lower die holder, a flaring lower die core connected with a flaring piston rod is arranged in the center of the flaring punch-die, a flaring material pushing ring and a flaring material pushing rod are both arranged in a flaring fixing ring, a flaring upper die core is arranged in the center of the flaring material pushing ring, and the flaring fixing ring is arranged on the flaring upper die holder. The structure of the flaring forming die and the principle of preventing the instability and wrinkling of the tank body are similar to those of the stretching forming die.

Preferably, the trimming die comprises a trimming lower die holder and a trimming female die arranged on the trimming lower die holder, the trimming positioning upper die core is fixed on the trimming upper die holder, a trimming fixing ring is fixed on the trimming upper die holder, the trimming pressing ring is arranged in the trimming fixing ring, and the trimming male die is arranged in the trimming pressing ring and positioned on the outer side of the trimming positioning upper die core.

Preferably, the cup punching die is of an independent structure, the stretch forming die, the flaring forming die and the trimming die are arranged on the same die frame to form a progressive forming die, the die frame comprises a die frame lower template used for fixing a lower die and a die frame upper template used for fixing an upper die, the die frame lower template is provided with a transition plate, the die frame upper template is provided with a die frame cylinder, and a tank body clamping and conveying device is arranged among the cup punching die, the stretch forming die, the flaring forming die and the trimming die. The operation principle of the progressive forming die is as follows: under the action of a power source, an upper template of a die frame drives upper dies of the three dies to move downwards, a stretching female die of a stretching forming die and a stretching lower die core act to complete a stretching forming process, and tank wall reinforcing ribs and tank bottom sinking plane forming are completed at a lower dead point; the flaring female die of the flaring forming die and the flaring lower die core act to complete the flaring forming process; the trimming positioning upper die core of the trimming die is used for positioning the trimming tank body, then the trimming male die continues to move downwards to be matched with the trimming female die to finish trimming, the finished tank body after trimming falls into the trimming lower die seat and is sent out of the working range of the die, and the forming upper die plate drives the upper dies of the three dies to move upwards to the upper dead point, so that the one-step forming process is finished.

As another alternative, the cup punching die, the stretch forming die, the flaring forming die and the trimming die are all independent structures, and the tank body clamping and conveying device is arranged among the cup punching die, the stretch forming die, the flaring forming die and the trimming die. The processes are independent, power sources are used respectively, the purpose of product forming can be achieved, and only the power sources are added and independent die structures are adopted.

The forming step of the invention comprises the forming of the transition structure of the can body, and the invention does not describe in detail the can body clamping and conveying device used in the working process of the die, which belongs to the prior art. Meanwhile, the present invention expresses the corresponding mold structure by the definition of the structure of the can body (such as height, cross-sectional area, etc.), which is well understood by those skilled in the art.

The invention has the beneficial effects that: the forming process and the forming die of the high-tensile straight-wall square tank can effectively solve the problems of tank body fracture and unstable wrinkling at the transition fillet of the tank body on the premise of ensuring various performance requirements of the conical tank, can simplify the production process, reduce the equipment quantity, reduce the production investment and cost, and have high practical value.

Drawings

FIG. 1 is a schematic view of a change in the structure of a can body during the forming process of the present invention;

FIG. 2 is a schematic view of a construction of the cup die of the present invention;

FIG. 3 is a schematic view of a configuration of a stretch-forming die of the present invention;

FIG. 4 is a schematic diagram of a flare forming die of the present invention;

FIG. 5 is a schematic view of one embodiment of the trimming die of the present invention;

FIG. 6 is a schematic view of a progressive die of the present invention;

FIG. 7 is a schematic structural view of a progressive die set of the present invention;

figure 8 is a schematic view of one construction of the finished can body of the present invention.

In the figure: I. a cup punching die, a II progressive forming die, a III stretching forming die, an IV flaring forming die, a V trimming die, a VI die carrier, a cup body, a 2 stretching can body, a 3 flaring can body, a 4 finished can body, an outward flanging, a 6 flaring, a 7 die carrier lower template, an 8 transition plate, a 9 die carrier cylinder, a 10 die carrier upper template, a 11 cup punching lower template, a 12 cup punching cylinder, a 13 cup punching lower template, a 14 cup punching ejector rod, a 15 cup punching fixing seat, a 16 cup punching concave die, a 17 cup punching ejector ring, a 18 cup punching lower die core, a 19 cup punching discharging ring, a 20 cup punching convex-concave die, a 21 cup upper die core, a 22 cup punching upper die base, a 23 cup punching upper template, a 24 cup upper cylinder, a 25 spring, a 26 can wall reinforcing rib, a 27 can bottom sinking plane, a 28 flanging, a 29 notch, a 32 stretching lower template, a 32 stretching positioning ring, 33. the die comprises a drawing male die, a drawing female die, 34 drawing lower die cores, 35 drawing piston rods, 36 drawing ejector rings, 37 drawing ejector rods, 38 drawing fixing rings, 39 drawing die cores, 40 drawing upper die bases, 41 flaring lower die bases, 42 flaring male die cores, 43 flaring lower die cores, 44 flaring piston rods, 45 flaring ejector rings, 46 flaring ejector rods, 47 flaring upper die cores, 48 flaring fixing rings, 49 flaring upper die bases, 51 trimming lower die bases, 52 trimming female dies, 53 trimming positioning upper die cores, 54 trimming male dies, 55 trimming press rings, 56 trimming fixing rings and 57 trimming upper die bases.

Detailed Description

The following is a further description of embodiments of the present invention by way of examples and with reference to the accompanying drawings.

Example 1

In example 1 shown in fig. 1, a process for forming a high tensile straight-walled square can comprises the following steps:

a. the blanking and cup punching process is used for slicing and blanking the tank body materials and simultaneously stretching the tank body materials to form a cup body 1, the height of the cup body is 50% of the height of a finished tank body, the cup body is cylindrical and is of a straight wall structure, the diameter of the cup body is 2 times of the width of the middle cross section of the finished tank body, the cross section area of the opening of the cup body is the same as the middle cross section area of the cup body, and the cup body which is subjected to the blanking and cup punching process is conveyed to the stretch forming process through a tank body clamping and conveying device.

b. And a stretching forming process, wherein the limiting type is adopted to reduce the forming, the cross section area of the cup body after the blanking and cup punching process is reduced, the second stretching of the stretching height is increased, the ratio of the height of the stretching tank body 2 to the width of the cross section is greater than 1, the stretching tank body is stretched while the planar forming of the tank wall reinforcing ribs and the tank bottom sinking is completed, and the stretching tank body is conveyed to the flaring forming process through a tank body clamping and conveying device after the stretching forming process is completed.

c. And in the flaring forming process, enveloping forming is adopted, the material is formed at the downward enveloping forming opening part, the influence of the stretching process on the tank opening part is reduced, the flaring part of the tank body matched with the easy-open cover and the flanging fillet forming are completed, and the flaring tank body 3 completing the flaring forming process is conveyed to the trimming process through the tank body clamping and conveying device.

d. And a trimming process, namely cutting redundant materials of the flanging to enable the flanging to meet the matching requirement of the double-seaming tank cover, and moving the finished tank body 4 which finishes the trimming process out of the trimming process through the tank body clamping and conveying device.

A forming die of a high-tensile straight-wall square tank comprises:

the cup punching die I (see figure 2) is applied to the blanking and cup punching process and is used for slicing and blanking tank body materials and forming a cup body 1 through primary stretching, the cup body after primary stretching is cylindrical, the wall of the cup body is of a straight wall structure, the height of the cup body is 50% of the height of a finished tank body, the diameter of the cup body after primary stretching is 2 times of the width of the middle cross section of the finished tank body, the middle cross section area of the cup body after primary stretching is 88% of the middle cross section area of the finished tank body, and the cross section area of an opening of the cup body after primary stretching is the same as the middle cross section area of the cup body.

Stretch forming die III (see fig. 3), be applied to the stretch forming process for the cup after the first time is stretched and is formed tensile jar body 2 for the second time, include and sink into the primary forming (see fig. 8) of plane 27 at jar wall strengthening rib 26 and tank bottoms, and form flanging 5 at the jar mouth, tensile jar body is cuboid shape and its jar wall is straight wall structure, wherein the tank bottoms sinks into planar periphery and forms chimb 28, and the chimb is equipped with the breach 29 that is used for dodging the easy-open end pull ring near jar body length direction's both ends. The height of the stretched tank after the second stretching is 70-90% of the height of the finished tank 4, the middle cross-sectional area of the stretched tank after the second stretching is 93% of the middle cross-sectional area of the finished tank, and the flanging width of the stretched tank after the second stretching is 12.5 times of the flanging width of the finished tank.

And the flaring forming die IV (see figure 4) is applied to a flaring forming process and is used for carrying out third-time stretching forming on the stretched tank body after the second stretching to form a formed tank body 3, and comprises the final forming of tank wall reinforcing ribs and tank bottom reinforcing ribs, the forming of a flaring 6 and a flanging fillet at the opening end of the tank body, the height of the formed tank body after the third stretching is the height of the finished tank body, the middle cross-sectional area of the formed tank body is the middle cross-sectional area of the finished tank body, and the flanging width of the formed tank body after the third stretching is 4 times of the flanging width of the finished tank body.

And the trimming die V (see figure 5) is used for trimming the edge of the flanging at the opening of the formed tank body, and the width and the fillet structure of the flanging of the finished tank body after trimming meet the matching requirements of the double-seaming tank cover.

The punching cup die I is a blanking forming compound die and comprises a punching cup lower die plate 11 used for supporting, a punching cup lower cylinder 12 arranged in the punching cup lower die plate, a piston of the punching cup cylinder is connected with a punching cup ejector rod 17 through a punching cup ejector rod 14, a punching cup lower die base 13 used for fixing a punching cup lower die core 18, a punching cup fixing base 15 used for fixing a punching cup female die 16, a punching cup upper die core 21 connected with a punching cup upper cylinder 24 is arranged in the center of a punching cup convex-female die 20, a punching cup discharging ring 19 is arranged on the periphery of the punching cup convex-female die, a punching cup discharging ring is fixed with a punching cup upper die base 22 used for fixing a punching cup upper die through a spring 25, and a punching cup upper die base is arranged on the punching cup upper die plate 23.

The stretching forming die III comprises a die 31 and a stretching punch-die 33 arranged on a stretching die holder, a stretching positioning ring 32 is formed on the periphery of the upper end of the stretching punch-die, a stretching lower die core 34 and a stretching piston rod 35 connected with the stretching lower die core are arranged in the center of the stretching punch-die, a stretching ejection ring 36 and a stretching ejector rod 37 are arranged in a stretching fixing ring 38, the stretching fixing ring is arranged on a stretching upper die holder 40, and a stretching die core 39 is arranged in the center of the stretching ejection ring.

Flaring forming die IV is used for jar body flaring shaping process, including flaring die holder 41 and the flaring punch-die 42 of setting on the flaring die holder, the central authorities of flaring punch-die are equipped with the flaring die core 43 of being connected with flaring piston rod 44 down, and flaring liftout circle 45 and flaring ejector pin 46 all set up in flaring retainer plate 48, and flaring liftout circle's central authorities are equipped with flaring upper die core 47, and the flaring retainer plate sets up on flaring upper die base 49.

The trimming die V comprises a trimming lower die holder 51 and a trimming female die 52 arranged on the trimming lower die holder, the trimming positioning upper die core 53 is fixed on a trimming upper die holder 57, a trimming fixing ring 56 is fixed on the trimming upper die holder, a trimming pressing ring 55 is arranged in the trimming fixing ring, and a trimming male die 54 is arranged in the trimming pressing ring and positioned outside the trimming positioning upper die core.

The cup punching die is of an independent structure, the stretching forming die, the flaring forming die and the trimming die are arranged on the same die carrier VI to form a progressive forming die II (see figure 6), the die carrier comprises a die carrier lower template 7 for fixing a lower die and a die carrier upper template 10 for fixing an upper die, a transition plate 8 is arranged on the die carrier lower template, a die carrier cylinder 9 (see figure 7) is arranged on the die carrier upper template, and a tank body clamping and conveying device (not shown in the figure) is arranged among the cup punching die, the stretching forming die, the flaring forming die and the trimming die.

Example 2

The cup punching die, the stretch forming die, the flaring forming die and the trimming die in the embodiment 2 are all independent structures, and the can body clamping and conveying device is arranged among the cup punching die, the stretch forming die, the flaring forming die and the trimming die, and the rest is the same as the embodiment 1.

During the stretching forming process of the tank body material, the sheet material is changed into a three-dimensional box-shaped member, and the edge parts of the male die and the female die have horizontal tensile force and vertical extrusion force, so that the tank body material has a wrinkling tendency. When the edge-holding force of the mold is insufficient, the edges of the can body material are liable to be unstably wrinkled, and this phenomenon is often improved by increasing the edge-holding force. However, in order to reduce the production cost and improve the product competitiveness, manufacturers use high-hardness and low-ductility can body materials, and if the traditional flat edge pressing mode is adopted, the workpiece is easy to stretch and break by continuously improving the edge pressing force. The cup making process of the invention changes the mode of the wide flanging square cup body which is usually adopted in the past square can forming, the large-diameter straight-wall round can-shaped cup body without the flanging is adopted, the structure without the flanging relieves the limitation of blank holder stretching on the material flowability, greatly increases the material flowability, the large-diameter circular structure ensures that the tank body material in the cup punching stage is uniformly stressed on the tank wall, the problem of instability wrinkling or tensile fracture is not easy to occur, the molded cup body is fully expanded, the deformation of the subsequent stretching process is relatively less, therefore, the problems that the tank body material has the tendency of wrinkling and is easy to cause unstable wrinkling and tensile rupture of the tank body material due to the fact that the horizontal tensile force and the vertical extrusion force exist at the edge parts of the male die and the female die in the punching and cup stretching process of the traditional square tank are greatly reduced.

In addition to the above embodiments, technical features or technical data of the present invention may be reselected and combined to constitute a new embodiment within the scope disclosed in the claims and the specification of the present invention, and the embodiments of the present invention not described in detail can be easily implemented by those skilled in the art without creative efforts, and thus the embodiments not described in detail should be regarded as specific embodiments of the present invention and are within the protection scope of the present invention.

Claims (8)

1. A forming process of a high-tensile straight-wall square tank is characterized by comprising the following steps:

a. a blanking and cup punching process, wherein the blanking and cup punching process is used for slicing and blanking can body materials and simultaneously stretching the can body materials to form a cup body (1), the height of the cup body is 40-60% of the height of a finished can body (4), the cup body is cylindrical and has a straight wall structure, the diameter of the cup body is 1.8-2.2 times of the width of the cross section of the finished can body, the cross section area of an opening of the cup body is the same as the cross section area of the middle part of the cup body, and the cup body completing the blanking and cup punching process is conveyed to a stretching forming process through a can body clamping and conveying device;

b. a stretching forming process, wherein limiting type reduction forming is adopted, the cross section area of the cup body after the blanking and cup punching process is reduced, the second stretching of the stretching height is increased, the ratio of the height of the stretching tank body (2) after the stretching forming process to the width of the cross section is larger than 1, the forming of the tank wall reinforcing ribs and the tank bottom sinking plane is completed during stretching, and the stretching tank body is conveyed to the flaring forming process through a tank body clamping and conveying device after the stretching forming process is completed;

c. The flaring forming process adopts enveloping forming, materials are formed at a downward enveloping forming opening part, the influence of the stretching process on the tank opening part is reduced, the flaring part of the tank body matched with the easy-open cover and the flanging fillet forming are completed, and the flaring tank body (3) completing the flaring forming process is conveyed to the trimming process through the tank body clamping and conveying device;

d. and a trimming process, namely cutting redundant materials of the flanging to enable the flanging to meet the matching requirement of the double-seaming tank cover, and moving the finished tank body which is subjected to the trimming process out of the trimming process through the tank body clamping and conveying device.

2. A forming die of a high-tensile straight-wall square tank, which is suitable for the forming process of the high-tensile straight-wall square tank in claim 1, and is characterized by comprising the following steps:

the cup punching die (I) is applied to a blanking and cup punching process and is used for slicing and blanking a tank material and forming a cup body (1) through first stretching, the cup body after the first stretching is cylindrical, the wall of the cup body is of a straight wall structure, the height of the cup body is 40-60% of the height of a finished tank body, the diameter of the cup body after the first stretching is 1.8-2.2 times of the width of the middle cross section of the finished tank body, the middle cross section area of the cup body after the first stretching is 85-90% of the middle cross section area of the finished tank body, and the cross section area of an opening of the cup body after the first stretching is the same as the middle cross section area of the cup body;

The drawing forming die (III) is applied to the drawing forming process and is used for carrying out secondary drawing on the cup body after primary drawing to form a drawn tank body (2), and comprises primary forming of sinking a plane (27) in a tank wall reinforcing rib (26) and a tank bottom and forming an outward flange (5) at a tank opening, wherein the drawn tank body is in a cuboid shape, the tank wall of the drawn tank body is in a straight wall structure, the height of the drawn tank body after secondary drawing is 70-90% of the height of a finished tank body (4), the middle cross-sectional area of the drawn tank body after secondary drawing is 90-95% of the middle cross-sectional area of the finished tank body, and the flange width of the drawn tank body after secondary drawing is 10-15 times of the flange width of the finished tank body;

the flaring forming die (IV) is applied to the flaring forming process and is used for carrying out third-time stretching forming on the stretched tank body after the second-time stretching to form a formed tank body (3), and comprises the final forming of tank wall reinforcing ribs and tank bottom reinforcing ribs, the flaring (6) forming at the opening end of the tank body and the flanging fillet forming, wherein the height of the formed tank body after the third-time stretching is the height of the finished tank body, the middle cross-sectional area of the formed tank body is the middle cross-sectional area of the finished tank body, and the flanging width of the formed tank body after the third-time stretching is 3-6 times of the flanging width of the finished tank body;

And the trimming die (V) is used for trimming and trimming the flanging part at the opening of the formed tank body, and the width and the fillet structure of the flanging of the finished tank body after trimming and trimming meet the matching requirements of the double-seaming tank cover.

3. The forming mold of the high-tensile straight-wall square can according to claim 2, the punching cup die (I) is a blanking forming compound die and comprises a punching cup lower die plate (11) used for supporting and a punching cup lower cylinder (12) arranged in the punching cup lower die plate, a piston of the punching cup cylinder is connected with a punching cup material ejection ring (17) through a punching cup ejector rod (14), a punching cup lower die holder (13) used for fixing a punching cup lower die core (18), a punching cup fixing holder (15) used for fixing a punching cup concave die (16), an upper cup punching mold core (21) connected with an upper cup punching cylinder (24) is arranged in the center of a cup punching convex-concave mold (20), a cup punching discharging ring (19) is arranged on the periphery of the cup punching convex-concave mold, the cup punching discharging ring is fixed with an upper cup punching mold base (22) used for fixing an upper cup punching mold through a spring (25), and the upper cup punching mold base is arranged on an upper cup punching mold plate (23).

4. The forming die of the high-tensile straight-wall square can according to claim 2, characterized in that the stretch forming die (III) comprises a drawing punch-die (31) and a drawing punch-die (33) arranged on a drawing lower die holder, a drawing positioning ring (32) is formed on the upper end periphery of the drawing punch-die, a drawing lower die core (34) and a drawing piston rod (35) connected with the drawing lower die core are arranged in the center of the drawing punch-die, a drawing ejection ring (36) and a drawing ejection rod (37) are arranged in a drawing fixing ring (38), the drawing fixing ring is arranged on a drawing upper die holder (40), and a drawing die core (39) is arranged in the center of the drawing ejection ring.

5. The forming die of the high-tensile straight-wall square tank, as claimed in claim 2, wherein the flaring forming die (IV) is used in the flaring forming process of the tank body, and comprises a flaring lower die holder (41) and a flaring punch-die (42) arranged on the flaring lower die holder, a flaring lower die core (43) connected with a flaring piston rod (44) is arranged in the center of the flaring punch-die, a flaring ejector ring (45) and a flaring ejector rod (46) are both arranged in a flaring retainer ring (48), a flaring upper die core (47) is arranged in the center of the flaring ejector ring, and the flaring retainer ring is arranged on a flaring upper die holder (49).

6. The forming die for the high-tensile straight-wall square can according to claim 2, wherein the trimming die (V) comprises a trimming lower die holder (51) and a trimming female die (52) arranged on the trimming lower die holder, the trimming positioning upper die core (53) is fixed on the trimming upper die holder (57), a trimming fixing ring (56) is fixed on the trimming upper die holder, the trimming pressing ring (55) is arranged in the trimming fixing ring, and the trimming male die (54) is arranged in the trimming pressing ring and is positioned outside the trimming positioning upper die core.

7. The forming die of the high-tensile straight-wall square can according to any one of claims 2 to 6, characterized in that the punching cup die is of an independent structure, the stretch forming die, the flaring forming die and the trimming die are arranged on the same die carrier (VI) to form a progressive forming die (II), the die carrier comprises a die carrier lower template (7) for fixing a lower die and a die carrier upper template (10) for fixing an upper die, the die carrier lower template is provided with a transition plate (8), the die carrier upper template is provided with a die carrier cylinder (9), and a can body clamping and conveying device is arranged among the punching cup die, the stretch forming die, the flaring forming die and the trimming die.

8. The forming die for the high-tensile straight-wall square can according to any one of claims 2 to 6, wherein the cup punching die, the stretch forming die, the flaring forming die and the trimming die are independent structures, and a can body clamping and conveying device is arranged among the cup punching die, the stretch forming die, the flaring forming die and the trimming die.

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