Metal product necking die and progressive die

Abstract

The utility model discloses a metal product necking die and a progressive die. The metal product necking die comprises an upper die set and a lower die set. The upper die set comprises an upper female die and a die core arranged in the upper female die, the cavity shape of the upper female die corresponds to the peripheral shape of a metal product, and the die core is made of a non-rigid material capable of elastically deforming / resetting; the lower die set comprises a lower female die, and the cavity shape of the lower female die corresponds to the shape of the bottom of the metal product. In a to-be-closed state, the distance between the mold core and the bottom of a to-be-necked metal product is smaller than the mold closing stroke of the upper mold set and the lower mold set; when the upper die set and the lower die set are combined, the die core abuts against the inner bottom wall of a to-be-necked metal product, is extruded and deforms in the direction of the inner circumferential wall of the to-be-necked metal product, and the inner circumferential wall of the to-be-necked metal product is extruded through deformation. The upper female die and the lower female die are matched to finish forming of the outer shape and the inner cavity shape of a cup metal product to be necked.

Description

Technical Field

[0001] The utility model relates to the technical field of metal forming, in particular to a metal product shrinking die and a progressive die. Background Art

[0002] Stamping dies can generally only produce metal equal-mouth cups (the cup body diameter does not change). It is rare to use stamping dies to produce some metal cup neckings (the cup body diameter gradually decreases toward the cup mouth) because the product cannot be demoulded under normal circumstances and cannot be formed into the required shape. The reason is that the necking diameter is small, and the diameter of the punch is the same as the necking position diameter, so it cannot be formed as required. If the punch is the same size as the outer shape, the mold cannot be demoulded. Therefore, in view of the current technological level, the production of metal cup necking products basically adopts spinning molds or welding of two halves of the product. This processing method is complicated and inefficient, and cannot produce efficiently, reduce costs, or achieve good use effects. Utility Model Content

[0003] The utility model aims to overcome the defects of the prior art and provide a metal product shrinking die and a progressive die.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] A metal product shrinking die, comprising: an upper die set and a lower die set; the upper die set comprises an upper concave die and a die core arranged in the upper concave die, the cavity shape of the upper concave die corresponds to the peripheral shape of the metal product, and the die core is a non-rigid material that can be elastically deformed / reset;

[0006] The lower die set comprises a lower concave die, the cavity shape of the lower concave die corresponds to the bottom shape of the metal product;

[0007] In the state to be molded, the distance between the mold core and the bottom of the metal product to be shrunken is less than the mold-closing stroke of the upper mold assembly and the lower mold assembly;

[0008] When the upper mold assembly is combined with the lower mold, the mold core abuts against the inner bottom wall of the metal product to be shrunken and is squeezed and deformed toward the inner circumferential wall of the metal product to be shrunken. The inner circumferential wall of the metal product to be shrunken is extruded through deformation, and the upper and lower concave molds are cooperated to respectively complete the forming of the external shape and the inner cavity shape of the metal cup to be shrunken.

[0009] Preferably, the upper die assembly further includes an upper clamping plate and an upper die base, the upper die is fixed to the upper clamping plate, and the upper clamping plate is arranged below the upper die base.

[0010] Preferably, the metal product has a channel for the mold core to extend into, the minimum diameter of the opening end of the channel is not less than the diameter of the mold core, and the diameter of the bottom of the channel is larger than the diameter of the opening end; the inner diameter of the cavity of the upper die gradually decreases from the end close to the lower die to the end away from the lower die.

[0011] Preferably, the expansion structure is a frustoconical expansion, the fixed end of the mold core is arranged at the bottom of the upper mold, and the free end thereof extends from the bottom of the upper mold to the open end, and the free end of the mold core extends outside the opening of the upper mold and is higher than the cavity depth of the upper mold.

[0012] Preferably, the expansion structure is a frustoconical expansion, the mold core is arranged in the upper die, extending from the bottom of the upper die to the open end, and the end of the mold core is higher than the cavity depth of the upper die.

[0013] Preferably, the lower die assembly further comprises a lower clamping plate, a lower pad and a lower die seat, and a lower punch is arranged at a position of the lower pad corresponding to the lower die.

[0014] Preferably, a spring is provided between the lower clamping plate and the lower die base, and a guide column is provided between the lower die set and the upper die set.

[0015] Preferably, the mold core is made of PU, tendon, or rubber material.

[0016] The utility model also provides a progressive die, including a multi-stage forming die, and also includes any of the above-mentioned metal product shrinking dies;

[0017] The multi-stage forming die comprises: a stretching forming die for forming a columnar cavity and a rotary cutting forming die for rotary cutting to separate the columnar cavity from a material strip, and the station of the metal product shrinking die is arranged behind the rotary cutting forming die.

[0018] Preferably, the multi-stage forming die also includes a first punching forming die for punching out guide nail holes, a second punching forming die for punching out process holes, a shaping forming die for forming stretching fillets, a third punching forming die for punching out center holes, a reverse chamfering forming die for forming chamfers on the shrinking surface, and a chopping die for chopping waste materials. The workstations of the first punching forming die and the second punching forming die are arranged before the stretching forming die.

[0019] The metal cup necking forming mold of the utility model uses an extrudable and deformable mold core to extrude the mold core radially to expand the mold core when the mold is closed, thereby completing the filling of the mold cavity, thereby solving the problem that the necking diameter is small, the diameter of the punch is consistent with that of the necking position, and the product cannot be formed as required. If the punch is consistent with the outer shape in size, the product cannot be formed into the necking shape, and the dimensional accuracy is not high and the flatness is uneven.

[0020] Furthermore, by setting a process hole at the cup mouth, problems such as wrinkles and cracks can be avoided when shrinking the mouth.

[0021] Furthermore, by shaping to form a stretched fillet, the shrinking section starts shrinking from that location, and during the shrinking process, a large impact on the bottom of the cup body can be avoided to cause deformation of the bottom, thereby ensuring the flatness of the bottom of the cup body.

[0022] Furthermore, by chamfering the necking surface, the flatness of the necking surface can be ensured after necking. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the metal necking cup of the utility model;

[0024] Figure 2 It is a structural schematic diagram of the metal necked cup of the utility model (from another perspective);

[0025] Figure 3 It is a structural schematic diagram (cross section) of the utility model of the necked cup forming mold;

[0026] Figure 4 It is a schematic diagram of the mold opening state of the shrink cup forming mold of the utility model;

[0027] Figure 5 It is a schematic diagram of the mold closing process of the shrink cup forming mold of the utility model;

[0028] Figure 6 It is a schematic diagram of the expansion of the mold core during the mold closing process of the shrink cup forming mold of the utility model;

[0029] Figure 7 It is a schematic diagram of the mold closing of the necked cup forming mold of the utility model;

[0030] Figure 8 It is a schematic diagram of the necking forming of the necking cup forming mold of the utility model;

[0031] Fig. 9 It is a structural schematic diagram (part) of the progressive die of the utility model;

[0032] Fig.10 It is a schematic diagram of the arrangement structure of each level of the progressive die of the utility model;

[0033] Fig.11 It is a position diagram of the processing procedures of each level of the progressive die of the utility model;

[0034] Fig.12 Flow chart of the metal cup necking forming method of the utility model;

[0035] Fig.13It is a process position diagram of the shrinkage forming of a metal cup of the utility model.

[0036] In the figure:

[0037] A first punching forming die 100, a second punching forming die 200, a stretching forming die 300, a shaping forming die 400, a third punching forming die 500, a reverse chamfering forming die 600, a rotary cutting forming die 700, a chopping die 800, and a metal product shrinking die 900;

[0038] Metal necked cup 10, cup mouth 11, stretched fillet 12, process hole 13, cup body 14;

[0039] Upper cover plate 701, upper die seat 702, upper inner stripper 703, upper clamping plate 704, side slider 705, upper stripper plate 706, upper template 707, lower concave die 708, lower template 709, inner stripper 710, lower clamping plate 711, lower die screw 712, ejector rod 713, lower die seat 714, ejector plate 715, spring 716, and foot pad 717;

[0040] Upper die set 910 , upper die 911 , model 912 , upper die base 913 , upper clamping plate 914 , lower die set 920 , lower die 921 , lower clamping plate 922 , lower die base 923 , lower pad 924 , lower punch 925 , spring 926 , guide column 930 . DETAILED DESCRIPTION

[0041] The following embodiments are given in conjunction with the accompanying drawings to further illustrate the specific implementation of the metal product shrinking mold of the present utility model. The metal product shrinking mold of the present utility model is not limited to the description of the following embodiments.

[0042] Embodiment 1

[0043] This embodiment provides a metal product shrinking die, which is used to process a metal sheet into a walking device with a shrinking structure, such as Figure 1-2 As shown, a metal necking cup is used as an example for explanation. As shown in the figure, the diameter of the cup mouth 11 of the metal necking cup is smaller than the diameter of the cup body 14, and the diameter of the cup body 14 gradually decreases from the bottom of the cup to the cup mouth in the direction of the L section, and the inner cavity and outer wall of the cup body are overall in a frustum-shaped necking structure. The position where the cup body 14 starts to neck is provided with a stretch fillet 12, and the cup mouth 11 is provided with a process hole 13, wherein the stretch fillet 12 and the process hole 13 have been formed before necking. The metal necking cup of this embodiment can be a cup body made of metal materials such as aluminum cup, copper cup, alloy, etc.

[0044] like Figure 3The figure shows a metal product necking mold 900 provided by the utility model, and the molding mold comprises: an upper mold set 910 and a lower mold set 920; the upper mold set 910 comprises an upper concave mold 911 and a mold core 912 arranged in the upper concave mold 911, the cavity shape of the upper concave mold 911 corresponds to the outer peripheral shape of the molded necking cup, that is, the inner diameter of the cavity shape of the upper concave mold 911 gradually decreases from one end close to the lower concave mold 921 to one end away from the lower concave mold 921, and the mold core 912 is a non-rigid material, that is, a material with elasticity, which can expand when squeezed and reset when not squeezed; The lower mold assembly 920 includes a lower die 921, the cavity of which corresponds to the bottom shape of the molded necked cup; the distance between the mold core 912 and the bottom of the cup to be necked in the open mold state is smaller than the clamping stroke of the upper mold assembly 910 and the lower mold assembly 920; when the upper mold assembly 910 and the lower mold assembly 920 are clamped, the mold core 912 abuts against the bottom of the cup to be necked and is squeezed and expands toward the inner wall of the cup to be necked, and cooperates with the upper die 911 and the lower die 921 to respectively complete the molding of the external shape and the inner wall shape of the cup to be necked. The inner cavity of the metal shrink cup 10 and the cup mouth 11 form a channel for the mold core 912 to penetrate. The minimum diameter of the opening end of the channel (i.e., the cup mouth 11) is not less than the diameter of the mold core 911, and the diameter of the bottom of the channel is larger than the diameter of the opening end. In this embodiment, the diameter of the mold core 192 is the same as the diameter of the cup mouth 11 of the metal shrink cup 10 (or slightly smaller than the diameter of the cup mouth 11), so that it can be pulled out of the metal shrink cup and can also penetrate into the cup mouth smoothly.

[0045] In this embodiment, the upper die assembly 910 further includes an upper clamping plate 914 and an upper die base 913 . The upper die 911 is fixed to the upper clamping plate 914 . The upper clamping plate 914 is disposed below the upper die base 913 .

[0046] In this embodiment, the lower mold assembly 920 also includes a lower clamping plate 922, a lower pad 924 and a lower mold base 923. The lower pad 924 is provided with a lower punch 925 at a position corresponding to the lower die 921. A spring 926 is provided between the lower clamping plate 922 and the lower mold base 923. A guide column 930 is provided between the lower mold assembly 920 and the upper mold assembly 910.

[0047] In this embodiment, the cavity shape of the upper die 911 is a flaring structure adapted to the shape of the outer wall of the metal product. When the mold core 912 extends into the channel and deforms, it squeezes the inner wall of the metal product to be shrunken and cooperates with the upper die 911 to jointly shape the inner and outer walls of the metal product.

[0048] Furthermore, the expansion structure is a frustum-shaped expansion (corresponding to the shape of the metal cup), the fixed end of the core mold 912 is arranged at the bottom of the upper die 911, and the free end thereof extends from the bottom of the upper die 911 to the open end, and the free end of the core mold 912 extends out of the opening of the upper die 911 and is higher than the cavity depth of the upper die 911, so that the core mold 912 has sufficient volume and compression to fill the internal space of the metal shrink cup 10, so that it forms sufficient pressure to squeeze the inner wall of the metal shrink cup 10 toward the inner cavity wall of the upper die 911.

[0049] In this embodiment, the mold core 912 is made of existing PU, tendon, rubber and other materials. When squeezed, the mold core 912 can expand radially to fill the gap inside the cup body, and continue to extrude to form mutual extrusion shaping with the inner wall of the upper concave mold 911, so that the cup body can be formed into a necking structure. If not squeezed, the mold core 912 returns to its original shape.

[0050] like Figure 4-8 The forming process of the metal product shrinking die of this embodiment is shown:

[0051] like Figure 4 As shown, in the mold opening state, the upper mold assembly 910 and the lower mold assembly 920 are in a separated state, and at this time, the aluminum cup (the cup to be formed 10a) is placed in the corresponding position of the lower concave mold 921 of the lower mold assembly 920.

[0052] like Figure 5-6 As shown, the lower mold assembly 920 acts as a movable mold assembly to close the mold upwards, or the upper mold assembly 910 acts as a movable mold assembly to close the mold downwards. During the closing process, the upper concave mold 911 squeezes the cup mouth to shrink toward the center.

[0053] like Figure 6 As shown, before the mold is closed, the mold core 912 abuts against the bottom of the cup body and is squeezed axially.

[0054] like Figure 7 As shown, during the gradual mold closing process, the mold core 912 expands radially due to the axial extrusion force, filling the inner wall of the cup body and exerting pressure on the inner wall of the cup body, so that the inner wall of the cup body exerts pressure in the direction of the upper concave mold 911 and the lower concave mold 921, so that the inner wall of the cup body cooperates with the upper concave mold 911, the lower concave mold 921 and the mold core 912 to form a finished necked cup that fits the cavity shape.

[0055] like Figure 8 As shown, after the necked cup 10b is formed, during the mold opening process, the axial extrusion force of the mold core 912 disappears, and the mold core 912 returns to its original shape, so that it can be smoothly extracted from the necked cup body.

[0056] Embodiment 2

[0057] like Figure 9-10 As shown, this embodiment provides a progressive die, which includes a multi-stage forming die and also includes the metal product shrinking die 900 as described in the above embodiment 1, wherein the metal product shrinking die 900 is arranged at the first stage or the last stage in the multi-stage forming die.

[0058] Combination Fig.11 As shown, as a specific embodiment, the multi-stage forming mold includes: a stretching forming mold 300 for forming a columnar cavity and a rotary cutting forming mold 700 for rotary cutting to separate the columnar cavity from the material strip, and a metal product shrinking mold 900 can be arranged behind the rotary cutting forming mold 700.

[0059] In one embodiment, the multi-stage forming die also includes a chopping die 800 , which is used to chop the waste after rotary cutting. The metal product shrinking die 900 can also be arranged after the chopping die 800 .

[0060] As a further improvement, the multi-stage forming die further comprises a second punching forming die 200 for punching out process holes, and the station of the second punching forming die 200 is arranged before the stretching forming die 300. By setting the second punching forming die 200, combined with Figure 1 and Figure 2 As shown, a process hole 13 can be formed at the cup mouth 11 before shrinking. The setting of the process hole 13 can avoid the material at the cup mouth 11 from wrinkling, extrusion and splitting, and can cooperate with the metal product shrinking mold 900 to obtain a metal shrinking cup with better shrinking effect.

[0061] As a further improvement, the multi-stage forming die further comprises a first punching forming die 100 for punching out the guide pin holes, and the station of the first punching forming die 100 is arranged before the second punching forming die 200. By punching out the guide pin holes, the punching position of the process hole 13 can be made accurate, thereby ensuring the shrinking process accuracy of the shrinking cup.

[0062] As a further improvement, the multi-stage forming die further comprises a shaping die 400 for forming a stretched fillet, and the shaping die 400 is arranged behind the stretching forming die 300. Figure 1 and Figure 2 As shown, the setting of the stretch fillet 12 allows the shrinking section to start shrinking from that position, and the shrinking process can avoid a large impact on the bottom of the cup body and cause deformation of the bottom.

[0063] As a further improvement, the multi-stage forming die further comprises a third punching forming die 500 for punching out a center hole, and the station of the third punching forming die is arranged after the stretching forming die.

[0064] As a further improvement, the multi-stage molding die also includes a reverse chamfering molding die 600 for forming a chamfer on the necking surface. The reverse chamfering molding die 600 is located after the stretching molding die 300. The chamfering setting can maintain the flatness of the cup mouth after necking molding.

[0065] In this embodiment, each level of the multi-stage forming mold can be realized by a person skilled in the art according to the prior art, and can be realized according to the existing metal cup forming mold, etc., and will not be described in detail here. Taking the rotary cutting forming mold 700 as an example, the rotary cutting forming mold 700 includes: an upper cover plate 701, an upper die seat 702, an upper inner stripper 703, an upper clamping plate 704, a side slider 705, an upper stripper plate 706, an upper template 707, a lower concave die 708, a lower template 709, an inner stripper 710, a lower clamping plate 711, a lower die screw 712, a ejector rod 713, a lower die seat 714, an ejector plate 715, a spring 716 and a foot 717.

[0066] like Fig.11 The process of forming each stage of the progressive die in this embodiment is shown, which is used to form the material strip into a metal necking cup, combined with Fig. 9 and Fig.10 As a specific implementation method, the arrangement order of the molding dies at each level is as follows:

[0067] A first punching and forming die 100, a second punching and forming die 200, a stretching and forming die 300, a shaping and forming die 400, a third punching and forming die 500, a reverse chamfering and forming die 600, a rotary cutting and forming die 700, a chopping and cutting die 800, and a metal product shrinking die 900; wherein, an empty step 0 is provided between the second punching and forming die 200 and the stretching and forming die 300, and an empty step 0 is provided between the reverse chamfering and forming die 600 and the rotary cutting and forming die 700, that is, the material strip is not processed at this location.

[0068] according to Fig.11 As shown, the first punching forming die 100 pre-punches out the guide pin hole and removes the excess material; the second punching forming die 200 removes the excess material and punches out the process hole according to the positioning of the guide pin hole; the stretching forming die 300 stretches the material strip to form a columnar cavity, that is, to form the prototype of an equal-mouth cup; the shaping forming die 400 performs shaping, and obtains the stretching fillet through die stamping, so that the shrinking starts at the stretching fillet during the subsequent shrinking, and the third punching forming die 500 punches out the center hole; the reverse chamfering forming die 600 completes the chamfering forming; the rotary cutting forming die 700 cuts out the columnar cavity; the chopping die 800 chop off the excess waste, and the metal product shrinking die 900 completes the shrinking forming. During the forming, the material strip is formed into a metal shrinking cup by passing through the multi-stage forming dies of the above-mentioned progressive die in sequence.

[0069] Embodiment 3

[0070] like Fig.12As shown, the utility model also provides a metal product shrinking method, comprising the steps of:

[0071] S1, preliminarily forming the material strip to obtain a cup to be shrunken, that is, forming a cup body of a uniform mouth;

[0072] S2, performing necking forming on the cup to be necked, wherein the necking forming on the cup to be necked is performed by using the metal product necking mold described in Example 1.

[0073] Combination Fig.11 and Fig.13 In this embodiment, step S1 includes:

[0074] S13, stretching the material strip to form a columnar cavity;

[0075] S17, peeling the columnar cavity to separate the columnar cavity from the material strip.

[0076] Among them, the columnar cavity formed by stretching can be formed by stamping through a stamping forming mold, and the columnar cavity can be separated from the material strip by rotary cutting through a rotary cutting forming mold.

[0077] In this embodiment, before step S13, step S1 further includes:

[0078] S12, using the guide pin hole as a precision positioning punching process hole, the process hole can be punched out by a punching forming die, of course, as an alternative implementation, it can also be cut by laser or other cutting methods. Figure 1 and Figure 2 As shown, a process hole 13 can be formed at the cup mouth 11 before shrinking. The setting of the process hole 13 can prevent the material at the cup mouth 11 from wrinkling, extrusion and splitting.

[0079] In this embodiment, before step S12, step S1 further includes:

[0080] S11, pre-punching is performed to punch out guide pin holes on the material strip. The guide pin holes can be punched out by a punching forming die. Of course, as an alternative implementation, they can also be cut by laser or other cutting methods. By punching out the guide pin holes, the punching position of the process hole 13 can be accurate, ensuring the shrinking process accuracy of the shrinking cup.

[0081] In this embodiment, after step S13, step S1 further includes:

[0082] S14, shaping the stretched columnar cavity to form a stretched fillet at the bottom edge, and the stretched fillet can be formed by a shaping mold. Figure 1 and Figure 2As shown, the setting of the stretch fillet 12 allows the shrinking section to start shrinking from that position, and the shrinking process can avoid a large impact on the bottom of the cup body and cause deformation of the bottom.

[0083] In this embodiment, after step S13, step S1 further includes:

[0084] S15, punching out a center hole at the bottom, the center hole can be formed by a punching forming die, or by laser cutting.

[0085] In this embodiment, after step S13, step S1 further includes:

[0086] S16, performing chamfering on the necking surface. The chamfering can be formed by a reverse chamfering forming die. The setting of the chamfering can maintain the flatness of the cup mouth after the necking forming.

[0087] In a further embodiment, after step S17 or step S2, step S1 further includes:

[0088] S18, chopping off the excess waste.

[0089] Each step of this embodiment can be completed in a progressive die through a single process, or can be completed in a combination of multiple molding dies or multiple processing steps.

[0090] It should be noted that in the description of the present invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc. indicate directions or positional relationships based on directions or positional relationships shown in the drawings, or directions or positional relationships that are usually placed when in use, and are only for the convenience of description, rather than indicating that the device or element referred to must have a specific direction, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish descriptions, and cannot be understood as indicating relative importance.

[0091] The above contents are further detailed descriptions of the present invention in combination with specific preferred implementations, and the specific implementation of the present invention cannot be considered to be limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A metal product shrinking die, include: The upper mold assembly (910) and the lower mold assembly (920) are characterized in that: The upper die set (910) comprises an upper die (911) and a die core (912) disposed in the upper die (911); the cavity shape of the upper die (911) corresponds to the peripheral shape of the metal product, and the die core (912) is a non-rigid material that can be elastically deformed / reset; The lower die set (920) comprises a lower concave die (921), and the cavity shape of the lower concave die (921) corresponds to the bottom shape of the metal product; In a state to be molded, the distance between the mold core (912) and the bottom of the metal product to be shrunken is smaller than the mold-closing stroke of the upper mold assembly (910) and the lower mold assembly (920); When the upper mold assembly (910) and the lower mold assembly (920) are molded together, the mold core (912) abuts against the inner bottom wall of the metal product to be shrunken and is squeezed and deformed toward the inner wall of the metal product to be shrunken. The inner wall of the metal product to be shrunken is squeezed by the deformation, and the upper concave mold (911) and the lower concave mold (921) are used to respectively complete the molding of the outer shape and the inner cavity shape of the metal cup to be shrunken.

2. The metal product shrinking die according to claim 1, Features: The upper die assembly (910) further comprises an upper clamping plate (914) and an upper die seat (913); the upper die (911) is fixed to the upper clamping plate (914); and the upper clamping plate (914) is arranged below the upper die seat (913).

3. The metal product shrinking die according to claim 1, Features: The metal product has a channel for the mold core (912) to extend into, the minimum diameter of the opening end of the channel is not less than the diameter of the mold core, and the diameter of the bottom of the channel is greater than the diameter of the opening end; the inner diameter of the cavity of the upper die (911) gradually decreases from one end close to the lower die (921) to one end away from the lower die (921).

4. The metal product shrinking die according to claim 3, Features: The cavity shape of the upper die (911) is a flaring structure adapted to the shape of the outer peripheral wall of the metal product. When the die core (912) extends into the channel and deforms, it squeezes the inner peripheral wall of the metal product to be shrunken and cooperates with the upper die (911) to jointly shape the inner peripheral wall and the outer peripheral wall of the metal product.

5. The metal product shrinking die according to claim 4, Features: The expansion structure is a frustoconical expansion, the fixed end of the mold core (912) is arranged at the bottom of the upper die (911), and the free end thereof extends from the bottom of the upper die (911) to the open end, and the free end of the mold core (912) extends outside the opening of the upper die (911) and is higher than the cavity depth of the upper die (911).

6. The metal product shrinking die according to claim 2, Features: The lower die assembly (920) further comprises a lower clamping plate (922), a lower pad (924) and a lower die seat (923), and the lower pad (924) is provided with a lower punch (925) at a position corresponding to the lower concave die (921).

7. The metal product shrinking die according to claim 6, Features: A spring (926) is provided between the lower clamping plate (922) and the lower die seat (923), and a guide column (930) is provided between the lower die assembly (920) and the upper die assembly (910).

8. The metal product shrinking die according to claim 1, Features: The mold core (912) is made of PU, tendon, or rubber material.

9. A progressive die, comprising a multi-stage forming die, Features: It also includes the metal product shrinking die (900) according to any one of claims 1 to 7; The multi-stage forming die comprises: a stretching forming die (300) for forming a columnar cavity and a rotary cutting forming die (700) for rotary cutting to separate the columnar cavity from a material strip, and the station of the metal product shrinking die (900) is arranged behind the rotary cutting forming die (700).

10. The progressive die according to claim 9, Features: The multi-stage forming die also includes a first punching forming die (100) for punching out guide pin holes, a second punching forming die (200) for punching out process holes, a shaping forming die (400) for forming a stretching fillet, a third punching forming die (500) for punching out a center hole, a reverse chamfering forming die (600) for forming a chamfer on a shrinking surface, and a chopping die (800) for chopping waste materials. The working stations of the first punching forming die (100) and the second punching forming die (200) are arranged before the stretching forming die (300).

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