CN112935092A - Mold and method for extruding sharp corner by stretching excircle - Google Patents

Abstract

The invention discloses a die for stretching an excircle extrusion sharp corner and a machining method thereof, wherein the die comprises an upper die holder and a lower die holder, and is used for machining a bottom tube of which the product is provided with a bottom hole, the edge of the upper part of the bottom tube is provided with an outward-folded bending part, and the die further comprises a punching station, a chamfering station, a pier returning station, a shaping station, a deburring station and a shooting station which are sequentially arranged. And one product is sequentially subjected to the operation of the stations to form a finished product. The invention has the beneficial effects that: the design requirement that the excircle at the bending part of the formed product is a sharp angle is met on the stamping equipment, the whole structure is reasonable in design, the structure is compact, and the production line operation can be realized.

Description

Mold and method for extruding sharp corner by stretching excircle

Technical Field

The invention belongs to the field of machinery, and particularly relates to a mold and a method for stretching an excircle and extruding a sharp corner.

Background

A cup-shaped workpiece is processed, and the workpiece is provided with a bottom tube, and a bottom hole is formed below the bottom tube. If a traditional stretching process is used, the outer circle of the bent part of the formed product is a round corner instead of the sharp corner required by the client as shown in figures 1 and 2. How to meet the requirements of customers on products is a technical problem to be solved urgently at present.

Disclosure of Invention

The invention aims to provide a die and a method for extruding a sharp corner by reliably stretching an excircle.

In order to achieve the purpose, the invention provides the following technical scheme:

a mold for stretching an excircle to extrude a sharp corner comprises an upper mold base and a lower mold base, and is used for a bottom tube of a processed product with a bottom hole, wherein the edge of the upper part of the bottom tube is provided with an outward-turned bending part, and the mold further comprises a punching station, a chamfering station, a pier returning station and a shaping station which are sequentially arranged;

the punching station comprises a first shearing female die and a first shearing punch for punching a bottom hole on a product, the first shearing female die is arranged on the lower die base, the first shearing punch is arranged on the upper die base, and the first shearing female die is provided with a first central hole into which the first shearing punch can be inserted;

the chamfering station comprises a chamfering punch head positioned on the lower die holder and a chamfering forming female die positioned on the upper die holder; the outer wall of the chamfering punch is provided with a step part for extruding the edge of a bottom hole of a product, and the chamfering punch also comprises an arc surface for connecting the step part to form a product chamfer;

the pier returning station comprises a pier returning forming punch head positioned on the lower die base and a pier returning forming female die positioned on the upper die base, the pier returning forming punch head is arranged in the bottom tube to limit the shape of the inner side of the bottom tube, and the pier returning forming female die is arranged above the bent part to downwards extrude the bent part, so that a right-angled bent structure is formed between the bent part and the bottom tube;

the shaping station comprises a second shearing female die positioned on the upper die base and a second shearing punch positioned on the lower die base, and the second shearing female die is provided with a second central hole into which the second shearing punch can be inserted.

Preferably, the deburring device further comprises a deburring station arranged behind the shaping station, the deburring station comprises a deburring forming female die located on the lower die holder and a deburring forming punch located on the upper die holder, and the deburring forming female die is provided with a third central hole capable of accommodating the deburring forming punch.

Preferably, still including setting up beat the station back behind the burring station, beat the station back including being located the shaping drift is clapped back to the upper die base and being located the shaping die is clapped back to the die holder, it has a fourth centre bore that runs through to clap the shaping die back, still includes one and sets up in the fourth centre bore in order to support clap back the interior support of shaping drift, interior support below sets up on a nitrogen spring through an ejector pin, be provided with cup-shaped nitrogen spring protection ring between ejector pin and the nitrogen spring.

Preferably, the upper die holder is provided with an upper base plate, the upper base plate is provided with an upper fixing plate, and the upper fixing plate is provided with a plurality of upper mounting holes for accommodating the first shearing punch, the chamfering forming die, the pier returning forming die, the second shearing die, the deburring forming punch and the patting forming punch; the lower die base is provided with a lower base plate, the lower base plate is provided with a lower fixing plate, and the lower fixing plate is provided with a plurality of lower mounting holes for accommodating the first shearing female die, the chamfering punch, the pier returning forming punch, the second shearing punch, the deburring forming female die and the patting forming female die.

Preferably, first shearing drift, chamfer shaping die, the shaping die of mound, second shearing die and burring shaping drift are established through a drift fixing base card respectively go up in the mounting hole, first shearing die, chamfer drift, the shaping drift of mound, second shearing drift, burring shaping die and the shaping die of clapping back are established through a die insert card respectively down in the mounting hole.

Preferably, the first shearing female die, the chamfering punch, the pier returning forming punch, the second shearing punch, the deburring forming female die and the patting forming female die are respectively sleeved with a positioning block for fixing a product.

Preferably, a floating block for supporting the edge of the product is sleeved outside the positioning blocks of the chamfering punch, the back pier forming punch and the second shearing punch.

Preferably, the die further comprises a stripper plate movably arranged on the upper fixing plate, a guide rod arranged on the lower die base penetrates through a through hole in the stripper plate and is movably arranged in a guide hole penetrating through the upper fixing plate and the upper backing plate, the upper fixing plate is further provided with an upper limiting block for limiting the position of the stripper plate, and the lower fixing plate is provided with a lower limiting block for limiting the position of the stripper plate.

The invention also provides a method for stretching the excircle to extrude the sharp corner, which comprises the step of stretching the excircle to extrude the sharp corner mould, and comprises the following steps:

1) punching, namely, a first shearing punch downwards enters a first central hole of a first shearing female die to punch a product on the first shearing female die, and a bottom hole is punched at the bottom of the product, wherein the diameter of the bottom hole is smaller than the designed diameter so as to ensure that redundant materials are reserved;

2) chamfering, wherein the chamfering forming female die supports the bending part of the product from top to bottom, and a chamfering punch head positioned on the lower die seat extrudes the product from bottom to top so as to extrude the material at the edge of the bottom hole to the bending part; the outer wall of the chamfering punch is provided with a step part and an arc surface connected with the step part, and the chamfer of the edge of the bottom hole is formed by punching through the arc surface; the outer diameter of the step part of the chamfering punch is 0.1-0.2 mm smaller than the inner diameter of the bottom tube;

3) the pier-returning forming punch head positioned on the lower die base extends into the bottom pipe to limit the bottom pipe, the outer diameter of the pier-returning forming punch head is equal to the inner diameter of the bottom pipe, and the end surface of the pier-returning forming punch head is flush with the designed upper surface of the bent part; the bending part is downwards extruded by a pier-returning forming female die positioned on the upper die base so as to downwards and outwards extrude redundant materials above the bending part, and therefore a right-angled bending structure is formed between the bending part and the bottom tube;

4) shaping, namely a second shearing punch head positioned on the lower die holder penetrates through a bottom tube and is inserted into a second central hole of a second shearing female die positioned on the upper die holder, the edge of the second shearing female die abuts against the bending part, the outer diameter of the second shearing punch head and the inner diameter of the second central hole are equal to the designed inner diameter of the bottom tube, the inner wall of the bottom tube is upwards extruded through the second shearing punch head, and redundant materials are upwards extruded and sheared at the second central hole to be shaped;

5) the deburring device comprises an upper die base, a lower die base, a deburring forming punch, a deburring forming female die and a deburring forming female die, wherein the upper die base is provided with the deburring forming punch, the lower die base is provided with the deburring forming female die, a third central hole of the deburring forming female die is provided with a third central hole, the outer diameter of the deburring forming punch and the inner diameter of the third central hole are both equal to the designed inner diameter of a bottom tube, and the deburring forming punch penetrates through the bottom tube and is inserted into the;

6) the back clapping is carried out, is located the portion of bending that the product was held from the below to the shaping die of clapping back of die holder is located the portion of bending of beating shaping drift punching press product downwards of upper die base, the ejector pin that sets up on nitrogen spring passes the fourth centre bore of clapping shaping die back and from upwards propping up the shaping drift of clapping back down, forms the buffering, reduces clapping back the dynamics of shaping drift punching press downwards.

Preferably, the back beating forming punch of the upper die base is provided with a step structure matched with the shape of a product.

The invention has the beneficial effects that: the design requirement that the excircle at the bending part of the formed product is a sharp angle is met on the stamping equipment, the whole structure is reasonable in design, the structure is compact, and the production line operation can be realized.

Drawings

FIG. 1 is a design structure of a product;

FIG. 2 is an enlarged view of a portion of FIG. 1 at A;

FIG. 3 is a schematic sectional view of the mold of the present invention in a closed state;

FIG. 4 is an enlarged view of a portion of FIG. 3 at B;

FIG. 5 is a schematic diagram of a workstation.

Detailed Description

The technical solution of the present patent will be described in further detail with reference to the following embodiments.

As shown in fig. 1 and 2, the product to be produced by the present invention is a cup-shaped structure, which has a bottom tube 10, a bottom hole 12 is formed at the bottom of the bottom tube 10, a lower edge of the bottom hole 12 is provided with a chamfer, and an upper edge of the bottom tube 10 is provided with an outwardly turned bent portion 14. A sharp angle of 90 deg. is formed between the bend 14 and the bottom tube 10 as shown in fig. 2.

As shown in fig. 3 to 5, the die for drawing the excircle extrusion sharp corner of the invention comprises an upper die holder 16 and a lower die holder 18 (the upper and lower positions are shown in fig. 3, which is also the state in normal use), wherein the lower die holder 18 is fixedly arranged on a lower supporting plate 21 through a lower supporting foot 19. An upper backing plate 20 is disposed on the upper die base 16, an upper fixing plate 22 is disposed on the upper backing plate 20, a lower backing plate 24 is disposed on the lower die base 18, and a lower fixing plate 26 is disposed on the lower backing plate 24. The upper backing plate 20 is fixed on the upper die holder 16 through a countersunk head screw, and the upper fixing plate 22 is fixed on the upper die holder 16 through a countersunk head screw; the lower backing plate 24 is fixed on the lower die base 18 through a countersunk screw, and the lower fixing plate 26 is fixed on the lower die base 18 through a countersunk screw. And a stripper plate 28 movably provided on the upper fixing plate 22, the stripper plate 28 being connected to the upper fixing plate 22 by a spring (not shown), the stripper plate 28 being returned downward by the spring force after punching, thereby removing the product attached to the punch.

The punching station 101, the chamfering station 102, the pier returning station 103, the shaping station 104, the deburring station 105 and the rephotography station 106 are sequentially arranged between the upper die holder 16 and the lower die holder 18. And one product is sequentially subjected to the operation of the stations to form a finished product. The basis for this is the ductility of the metal, which flows as it is squeezed during the stamping process. The working process comprises the following steps: firstly, a semi-finished workpiece is stretched and punched to form the basic structure of the figure 1, and the designed sharp corner is also a fillet;

firstly, placing a semi-finished workpiece at a punching station, and punching a bottom hole 12 at the punching station; the diameter of the bottom hole 12 is slightly smaller than the designed diameter, so that a part of material is added, the part of material is used for filling the round corner to form a designed sharp corner, and the diameter is adjusted according to actual conditions;

secondly, moving the semi-finished workpiece to a chamfering station, and extruding the redundant materials upwards to fill the corners except for generating designed chamfers on the edges of the bottom tube 10;

thirdly, moving the semi-finished workpiece to a pier returning station, and downwards beating the bent part 14 to extrude the redundant materials outwards to fill the round corners so as to form the shapes of sharp corners, wherein a space for inward expansion is reserved in the bottom tube 10, and the redundant materials can be expanded inwards;

fourthly, moving the semi-finished workpiece to a shaping station, and adjusting the inner diameter of the bottom tube 10 to meet the designed inner diameter requirement of the bottom tube 10;

fifthly, moving the semi-finished workpiece to a deburring station to remove burrs on the inner wall of the bottom tube 10;

and sixthly, moving the semi-finished workpiece to a back-beating station, and punching a designed step structure at the bending part 14 of the product to finish the final shape to form a finished product.

Specifically, the method comprises the following steps:

the punching station comprises a first shearing female die 30 and a first shearing punch 32, wherein the first shearing female die 30 is used for punching the bottom hole 12 on the product, the first shearing punch 32 is arranged on the lower die base 18, the first shearing female die 30 is provided with a first central hole 34 into which the first shearing punch 32 can be inserted;

the chamfering station comprises a chamfering punch 36 positioned on the lower die holder 18 and a chamfering forming female die 38 positioned on the upper die holder 16; the outer wall of the chamfering punch 36 is provided with a step part 40 for extruding the edge of the bottom hole 12 of the product, and the chamfering punch further comprises a cambered surface 42 for connecting the step part 40 and forming the product chamfer;

the back-heading station comprises a back-heading forming punch 44 positioned on the lower die base 18 and a back-heading forming die 46 positioned on the upper die base 16, the back-heading forming punch 44 is arranged in the bottom tube 10 to limit the shape of the inner side of the bottom tube 10, and the back-heading forming die 46 is arranged above the bent part 14 to press the bent part 14 downwards, so that a right-angled bent structure is formed between the bent part 14 and the bottom tube 10;

the reforming station includes a second shear die 48 located on the upper die base 16 and a second shear punch 50 located on the lower die base 18, the second shear die 48 being provided with a second central aperture 52 into which the second shear punch 50 is inserted.

The deburring device further comprises a deburring station arranged behind the shaping station, the deburring station comprises a deburring forming female die 54 positioned on the lower die base 18 and a deburring forming punch 56 positioned on the upper die base 16, and the deburring forming female die 54 is provided with a third central hole 58 into which the deburring forming punch 56 can be inserted.

The deburring machine further comprises a back-beating station arranged behind the deburring station, the back-beating station comprises a back-beating forming punch 60 positioned on the upper die base 16 and a back-beating forming die 62 positioned on the lower die base 18, the back-beating forming die 62 is provided with a fourth central hole 64 penetrating through, the deburring machine further comprises an inner support 65 arranged in the fourth central hole 64 and used for supporting the back-beating forming punch 60, a push rod 66 supports the inner support 65, and the lower part of the push rod 66 is arranged on a nitrogen spring 70 through a cup-shaped nitrogen spring protection ring 68. The patting forming punch 60 is provided with a step structure 61 matched with the product shape, and finally the product is formed.

The upper fixing plate 22 is provided with a plurality of upper mounting holes (not shown) for accommodating the first shearing punch 32, the chamfering forming die 38, the back upsetting forming die 46, the second shearing die 48, the deburring forming punch 56 and the back beating forming punch 60; the lower fixing plate 26 is provided with a plurality of lower mounting holes (not shown) for receiving the first shearing die 30, the chamfering punch 36, the back-heading forming punch 44, the second shearing punch 50, the deburring forming die 54, and the patting forming die 62.

The first shearing punch 32, the chamfering forming die 38, the pier returning forming die 46, the second shearing die 48 and the deburring forming punch 56 are respectively clamped in the upper mounting hole through a punch fixing seat 72, and the first shearing die 30, the chamfering punch 36, the pier returning forming punch 44, the second shearing punch 50, the deburring forming die 54 and the slapping forming die 62 are respectively clamped in the lower mounting hole through a die insert 74.

The first shearing female die 30, the chamfering punch 36, the pier-returning forming punch 44, the second shearing punch 50, the deburring forming female die 54 and the patting forming female die 62 are respectively sleeved with a positioning block 76 for fixing a product.

The positioning blocks 76 of the chamfering punch 36, the back-heading forming punch 44 and the second shearing punch 50 are sleeved with a floating block 78 for supporting the edge of the product.

A guide rod 80 disposed on the lower die holder 18 passes through the through hole of the stripper plate 28 and is movably disposed in a guide hole passing through the upper fixing plate 22 and the upper backing plate 20, an upper limit block 82 for limiting the position of the stripper plate 28 is further disposed on the upper fixing plate 22, and a lower limit block 84 for limiting the position of the stripper plate 28 is disposed on the lower fixing plate 26.

The specific method for stretching the excircle and extruding the sharp angle comprises the following steps:

1) punching, namely, a first shearing punch 32 downwards enters a first central hole 34 of a first shearing female die 30 to punch a product on the first shearing female die 30, and a bottom hole 12 is punched at the bottom of the product, wherein the diameter of the bottom hole 12 is smaller than the designed diameter so as to ensure that redundant materials are left;

2) chamfering, wherein the chamfering forming female die 38 supports against the bent part 14 of the product from top to bottom, and the chamfering punch 36 positioned on the lower die base 18 extrudes the product from bottom to top so as to extrude the material at the edge of the bottom hole 12 to the bent part 14; a step part 40 is arranged on the outer wall of the chamfering punch 36, the chamfering punch further comprises an arc surface 42 connected with the step part 40, and the chamfer of the edge of the bottom hole 12 is formed through punching by the arc surface 42; the outer diameter of the step part 40 of the chamfering punch 36 is 0.1-0.2 mm smaller than the inner diameter of the bottom pipe 10, so that a space for flowing of redundant materials is formed;

3) the back pier is formed, a back pier forming punch 44 positioned on the lower die base 18 extends into the bottom tube 10 to limit the bottom tube 10, the outer diameter of the back pier forming punch 44 is equal to the inner diameter of the bottom tube 10, and the end surface of the back pier forming punch 44 is flush with the designed upper surface of the bent part 14; the back pier forming female die 46 positioned on the upper die holder 16 downwards extrudes the bent part 14 to extrude the redundant material above the bent part 14 downwards, outwards and towards a designed sharp angle, so that a right-angled bent structure is formed between the bent part 14 and the bottom tube 10;

4) shaping, namely inserting a second shearing punch 50 positioned on the lower die holder 18 into a second central hole 52 of a second shearing female die 48 positioned on the upper die holder 16 through the bottom tube 10, enabling the edge of the second shearing female die 48 to abut against the bent part 14, enabling the outer diameter of the second shearing punch 50 and the inner diameter of the second central hole 52 to be equal to the designed inner diameter of the bottom tube 10, extruding the inner wall of the bottom tube 10 upwards through the second shearing punch 50, extruding the redundant material upwards and shearing the redundant material at the second central hole 52 to shape;

5) deburring, wherein a deburring forming punch 56 is arranged on the upper die holder 16, a deburring forming female die 54 and a third central hole 58 of the deburring forming female die 54 are arranged on the lower die holder 18, the outer diameter of the deburring forming punch 56 and the inner diameter of the third central hole 58 are equal to the designed inner diameter of the bottom tube 10, and the deburring forming punch 56 penetrates through the bottom tube 10 and is inserted into the third central hole 58 to remove burrs on the inner wall of the bottom tube 10;

6) the back beating is carried out, the back beating forming female die 62 located on the lower die holder 18 supports the bending part 14 of the product from the lower side, the back beating forming punch 60 located on the upper die holder 16 downwards punches the bending part 14 of the product, and the ejector rod 66 arranged on the nitrogen spring 70 penetrates through the fourth center hole 64 of the back beating forming female die 62 to upwards eject the back beating forming punch 60 from the lower side, so that buffering is formed, and the downward punching force of the back beating forming punch 60 is reduced.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims (10)

1. The utility model provides a tensile excircle extrusion closed angle mould, its includes upper die base and die holder, and its product that is used for processing has the bottom tube of bottom hole, bottom tube upper portion edge is equipped with the portion of bending of turning over the book, its characterized in that: the device also comprises a punching station, a chamfering station, a pier returning station and a shaping station which are arranged in sequence;

the punching station comprises a first shearing female die and a first shearing punch for punching a bottom hole on a product, the first shearing female die is arranged on the lower die base, the first shearing punch is arranged on the upper die base, and the first shearing female die is provided with a first central hole into which the first shearing punch can be inserted;

the chamfering station comprises a chamfering punch head positioned on the lower die holder and a chamfering forming female die positioned on the upper die holder; the outer wall of the chamfering punch is provided with a step part for extruding the edge of a bottom hole of a product, and the chamfering punch also comprises an arc surface for connecting the step part to form a product chamfer;

the pier returning station comprises a pier returning forming punch head positioned on the lower die base and a pier returning forming female die positioned on the upper die base, the pier returning forming punch head is arranged in the bottom tube to limit the shape of the inner side of the bottom tube, and the pier returning forming female die is arranged above the bent part to downwards extrude the bent part, so that a right-angled bent structure is formed between the bent part and the bottom tube;

the shaping station comprises a second shearing female die positioned on the upper die base and a second shearing punch positioned on the lower die base, and the second shearing female die is provided with a second central hole into which the second shearing punch can be inserted.

2. The die for stretching the outer circle and extruding the sharp corner according to claim 1, wherein: still including setting up burring station behind the plastic station, the burring station is including being located the burring shaping die of die holder and being located the burring shaping drift of upper die base, the burring shaping die is provided with one and can holds burring shaping drift male third centre bore.

3. The die for stretching the outer circle and extruding the sharp corner according to claim 2, wherein: still including setting up being in beat the station back behind the burring station, it is including being located to beat the station back of upper die base and clap the shaping drift and be located the shaping die is clapped back of die holder, it has a fourth centre bore that runs through to clap the shaping die back, still includes one and sets up in the fourth centre bore in order to support it beats the interior support of shaping drift back, interior support below sets up on a nitrogen spring through an ejector pin, be provided with cup-shaped nitrogen spring protection ring between ejector pin and the nitrogen spring.

4. The die for stretching the outer circle and extruding the sharp corner according to claim 3, wherein: the upper die base is provided with an upper base plate, the upper base plate is provided with an upper fixing plate, and the upper fixing plate is provided with a plurality of upper mounting holes for accommodating the first shearing punch, the chamfering forming female die, the pier returning forming female die, the second shearing female die, the deburring forming punch and the patting forming punch; the lower die base is provided with a lower base plate, the lower base plate is provided with a lower fixing plate, and the lower fixing plate is provided with a plurality of lower mounting holes for accommodating the first shearing female die, the chamfering punch, the pier returning forming punch, the second shearing punch, the deburring forming female die and the patting forming female die.

5. The die for stretching the outer circle and extruding the sharp corner according to claim 4, wherein: first shearing drift, chamfer shaping die, the mound shaping die that returns, second shearing die and burring shaping drift are established through a drift fixing base card respectively go up in the mounting hole, first shearing die, chamfer drift, the mound shaping drift that returns, second shearing drift, burring shaping die and the shaping die of clapping are established through a die insert card respectively down in the mounting hole.

6. The die for stretching the outer circle and extruding the sharp corner according to claim 5, wherein: the first shearing female die, the chamfering punch, the pier returning forming punch, the second shearing punch, the deburring forming female die and the patting forming female die are respectively sleeved with a positioning block for fixing a product.

7. The die for stretching the outer circle and extruding the sharp corner according to claim 6, wherein: and a floating block for supporting the edge of a product is sleeved outside the positioning blocks of the chamfering punch, the back pier forming punch and the second shearing punch.

8. The die for stretching the outer circle and extruding the sharp corner according to claim 4, wherein: the die holder is characterized by further comprising a stripper plate movably arranged on the upper fixing plate, a guide rod arranged on the lower die holder penetrates through a through hole in the stripper plate and is movably arranged in a guide hole penetrating through the upper fixing plate and the upper base plate, an upper limiting block for limiting the position of the stripper plate is further arranged on the upper fixing plate, and a lower limiting block for limiting the position of the stripper plate is arranged on the lower fixing plate.

9. A method of drawing an external cylindrical extrusion tip angle comprising the external cylindrical extrusion tip angle drawing die of any one of claims 1 to 8, characterized by comprising the steps of:

1) punching, namely, a first shearing punch downwards enters a first central hole of a first shearing female die to punch a product on the first shearing female die, and a bottom hole is punched at the bottom of the product, wherein the diameter of the bottom hole is smaller than the designed diameter so as to ensure that redundant materials are reserved;

2) chamfering, wherein the chamfering forming female die supports the bending part of the product from top to bottom, and a chamfering punch head positioned on the lower die seat extrudes the product from bottom to top so as to extrude the material at the edge of the bottom hole to the bending part; the outer wall of the chamfering punch is provided with a step part and an arc surface connected with the step part, and the chamfer of the edge of the bottom hole is formed by punching through the arc surface; the outer diameter of the step part of the chamfering punch is 0.1-0.2 mm smaller than the inner diameter of the bottom tube;

3) the pier-returning forming punch head positioned on the lower die base extends into the bottom pipe to limit the bottom pipe, the outer diameter of the pier-returning forming punch head is equal to the inner diameter of the bottom pipe, and the end surface of the pier-returning forming punch head is flush with the designed upper surface of the bent part; the bending part is downwards extruded by a pier-returning forming female die positioned on the upper die base so as to downwards and outwards extrude redundant materials above the bending part, and therefore a right-angled bending structure is formed between the bending part and the bottom tube;

4) shaping, namely a second shearing punch head positioned on the lower die holder penetrates through a bottom tube and is inserted into a second central hole of a second shearing female die positioned on the upper die holder, the edge of the second shearing female die abuts against the bending part, the outer diameter of the second shearing punch head and the inner diameter of the second central hole are equal to the designed inner diameter of the bottom tube, the inner wall of the bottom tube is upwards extruded through the second shearing punch head, and redundant materials are upwards extruded and sheared at the second central hole to be shaped;

5) the deburring device comprises an upper die base, a lower die base, a deburring forming punch, a deburring forming female die and a deburring forming female die, wherein the upper die base is provided with the deburring forming punch, the lower die base is provided with the deburring forming female die, a third central hole of the deburring forming female die is provided with a third central hole, the outer diameter of the deburring forming punch and the inner diameter of the third central hole are both equal to the designed inner diameter of a bottom tube, and the deburring forming punch penetrates through the bottom tube and is inserted into the;

6) the back clapping is carried out, is located the portion of bending that the product was held from the below to the shaping die of clapping back of die holder is located the portion of bending of beating shaping drift punching press product downwards of upper die base, the ejector pin that sets up on nitrogen spring passes the fourth centre bore of clapping shaping die back and from upwards propping up the shaping drift of clapping back down, forms the buffering, reduces clapping back the dynamics of shaping drift punching press downwards.

10. The method of claim 9, wherein the step of drawing the outer circle extrudes the sharp corner comprises the steps of: the back beating forming punch of the upper die base is provided with a step structure matched with the shape of a product.

Images