CN104959460B - Slant punching die structure and punching method for automobile metal plate punch piece - Google Patents

Abstract

The invention relates to a die structure for an automobile metal plate punch piece and a punching method thereof, and provides a slant punching die structure of the automobile metal plate punch piece. The slant punching die structure of the automobile metal plate punch piece comprises a first sliding block mechanism (15) which moves horizontally and is provided with a punching concave die (8) and a second sliding block mechanism which moves aslant and is provided with a punching convex die (4). A material returning rod (10) is connected with the first sliding block mechanism through a limiting unit and a reset spring (9). When the material returning rod (10) makes contact with a stop dog (13), the reset spring (9) is pressed, the end portion of the material returning rod (10) moves outward and stretches out of waste material (19) pushed out of a hole cavity of the punching concave die (8). The punching method comprises the four stages that a die is opened, and the punch piece is placed; the die is closed, and punching is conducted; punching is finished, and the die is opened; the waste material is pushed out, and the punch die is taken out. According to the slant punching die structure of the automobile metal plate punch piece and the punching method thereof, the waste material of a slant punched hole is guaranteed to smoothly flow to a waste material sliding plate or a waste material groove, at the same time, the specific intensity of the die can be improved, the conveying condition of taking and placing the punch piece on a production line is improved, stable component positioning is guaranteed, the production takt is improved, and the production efficiency is improved.

Description

An oblique punching die structure and punching method for automobile sheet metal stamping parts

technical field

The invention relates to a die structure and punching method for automobile sheet metal stamping parts, in particular to an oblique punching die structure and punching method for automobile sheet metal stamping parts.

Background technique

At present, in the field of automobile manufacturing, the outflow direction of waste materials for punching sheet metal stamping parts is usually the same as the punching direction. This stamping method is generally feasible for flat stamping parts. Feeding, punching , Cutting, also suitable for automation. However, for the edge of one side of the plate, it is bent twice to form a cross-section similar to an n shape, and punching holes at the folded edge, it is difficult to discharge the waste after loading, punching, blanking and punching, especially for flat plates Parts with larger areas are more difficult. For example, the rear cover parts of passenger cars have a large area, and several rectangular lamp holes must be punched out after the lower edge is bent twice. The current traditional punching method is difficult to achieve.

In addition, for the oblique punching of some sheet metal stamping parts, it is impossible to realize the removal of waste materials. In order to successfully complete the bending side punching of bending parts, the traditional hook punching mechanism or rotating sheet metal stamping parts are generally used. Rotating the bent edge to vertical is accomplished with a horizontal side impact mechanism; however, these mechanisms tend to have some problems.

First, for the punching mechanism, after the punching is completed, in order to ensure the smooth removal of the parts, the punching parts in the punching mechanism need a larger stroke, but the mechanism slider must be installed in the reserved space For parts such as the upper punching punch and the side hold-down plate, the hooking parts are usually designed to have a triangular, trapezoidal or wedge-shaped cross-section to ensure a certain clearance stroke, but such a design often leads to the thinning of the hooking parts. Poor strength and poor stress state not only affect the punching accuracy, but also easily cause the slider to break, posing a great safety hazard. Therefore, this form of punching is subject to certain restrictions in the application of side punching and oblique punching of large and medium-sized sheet metal stamping parts.

Referring to Fig. 1, a punching die is provided on the punching mechanism 32. After the punching is completed, the driving device 32b of the punching mechanism is activated, and the punching part 32a moves toward the upper left direction for a stroke h, and the workpiece 17 is taken out.

Second, for the horizontal side punching mechanism, although the normal punching and waste flow can be completed after the bending side is placed vertically, the vertical or oblique placement of the non-bending side will cause parts The drop and depth are large, and the pick-and-place stroke of the parts in the production process of the automatic line is particularly large, and the running stroke of the upper mold is large, which seriously affects the beat of the assembly line and production efficiency. In addition, the positioning of the parts is difficult, and the unstable positioning will increase the scrap rate and shutdown rate. It will cause losses to production, and it will also cause the shape of the waste outflow path to be complicated, and it is easy to store waste, and it is invisible. These are taboos for automated production.

With reference to Fig. 2, the workpiece 17 is placed vertically. After the bending edge to be processed has completed normal punching and waste material outflow, the upper mold 21 moves upward for a relatively large stroke, and the workpiece 17 can be taken out.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of the prior art and provide a tool that can safely and conveniently place stamping parts, facilitate the automatic ejection of waste materials after punching, and facilitate the removal of workpieces after punching, and facilitate the transfer on the production line. Reasonable body structure, good strength, and a mold structure that is not easily damaged, and a corresponding punching method is proposed.

The purpose of the present invention is achieved by the following technical solutions:

An oblique punching die structure for automobile sheet metal stamping parts, characterized in that:

The oblique punching die mechanism includes a first slider mechanism and a second slider mechanism, the first slider mechanism is a slider mechanism that moves horizontally, the second slider mechanism is a slider mechanism that moves obliquely, and the second slider mechanism is a slider mechanism that moves obliquely. The working surfaces of the first slider mechanism and the second slider mechanism are arranged opposite to each other;

The first slider mechanism is provided with a punching die, the second slider mechanism is provided with a punching die, and the punching direction of the punching die is consistent with the punching die;

A material ejection rod, the material ejection rod is connected with the first slider mechanism through a limit unit and a return spring;

a stopper, the stopper is fixedly connected on the base;

During the movement of the first slider mechanism away from the second slider mechanism, its ejection rod contacts the stopper, presses the return spring, and the end of the ejection rod moves outward to extend out of the cavity of the punching die ;

The first slider mechanism and the second slider mechanism are the lower mold parts of the oblique punching die mechanism. When the upper and lower molds are closed, the first slider mechanism and the second slider mechanism are closed, When the upper and lower molds are opened, the first slider mechanism and the second slider mechanism are separated;

Described stamping part is the n shape of a long side in the observation direction of the schematic diagram of the mold of the present invention, the long side is a large panel, the short side is a punching plate, and the middle is a bending side;

The second slider mechanism includes an upward slanting guide plate, and the punching punch is arranged on the upward slanting guide plate;

The upper surface of the first slider mechanism is the rest surface of the long side of the large panel of the stamping part,

The length of the punching die and the ejector rod withdrawing from the tail is less than the length of the bending edge of the stamping part;

When the first slider mechanism and the second slider mechanism are closed, the punching punch and the punching die merge, the short side of the stamping part is clamped therebetween, and the punching die is against the inner wall of the bending edge of the stamping part.

Still further, when the stamping part is placed, the port with the short side bent inwards maintains a horizontal distance d from the protruding end of the punching die, and the length of d is 5-10 mm.

Still further, the contact surface between the stripping rod and the stopper is a vertical surface, or a surface that forms an angle with the vertical, and if the angle between the punching direction of the mold and the horizontal direction is α, then the contact surface and The angle formed by the vertical is smaller than α/2.

Still further, a through hole consistent with the moving direction of the ejector rod is opened at the tail of the ejector rod, and a limit bolt fixed on the punching die is inserted into the through hole, and the bolt head of the limit bolt limits the direction of the ejector rod. The tail pops out.

Still further, the top of the punching punch is also provided with a side holding plate supported by a side holding plate spring, and the side holding plate is provided with a punch hole matching the punch.

Still further, an ejector pin is arranged on the protruding end surface of the punching punch and/or the stripping rod.

Still further, the second slider mechanism also includes a slider A that moves up and down, a slider B that moves horizontally through an inclined plane, and a slider C that moves obliquely through a vertical plane; the first slider mechanism It also includes a D slider that moves up and down, which is converted into an E slider that moves horizontally through an inclined plane.

A punching method for an oblique punching die structure as described in the automobile sheet metal stamping parts, characterized in that: adopting the technical scheme has four stages,

The first stage: the mold is opened and the stamping is placed

The upper binder plate and the upper die are in the open state of the top dead center of the press, the punching die installed on the first slider mechanism and the punch punch installed on the second slider mechanism are separated from each other, the stopper and the ejection rod In the contact or non-contact state, the ejector rod is placed in the cavity of the punching die by the return spring and the limit unit; the bending side and the short side of the stamping part are downward, and the long side is placed on the an upper surface of the first slider mechanism;

Second stage: mold closing, punching

The upper mold and the upper binder plate move downward, the punching die on the first slider mechanism and the punching punch installed on the second slider mechanism move towards each other, and the punching punch moves in the direction of the inclined upward guide plate, and the long side of the stamping part The cavity between the upper die and the upper surface of the first slider mechanism, the punching die is against the inner wall of the bending side of the stamping part, and the short side of the stamping part is clamped between the punching die and the cutting edge of the punching die During this period, the upper mold and the upper binder plate continue to move downward, the punching punch punches holes, and the punching waste is contained in the cavity of the punching die;

The third stage: the punching is completed and the mold is opened

The upper die drives the upper clamping plate to move upward together, the upper clamping plate is released from the stamping part, the punching die on the first slider mechanism and the punching punch installed on the second slider mechanism are separated from each other, and the punching punch leaves the stamping part , the ejector rod on the punching die just touches the stopper;

The fourth stage: Ejection of scrap, removal of stamping parts

The punching die continues to retreat, the ejector rod on the punching die presses the block, squeezes the return spring, the end of the ejector rod moves outward, and the punching waste is pushed out of the cavity of the punching die and falls into the On the scrap slide below or in the scrap chute, remove the stamping.

Beneficial effects of the present invention:

For special automobile sheet metal stamping parts, special structure: large-area sheet, punching holes are located at the folded edge of one side and folded edge, adopt this technical solution:

(1) Solve the difficult problem of waste material flow out, and ensure that the punching waste material flows out smoothly to the waste material slide plate or waste material groove;

(2) In order to improve the strength of the mold tool body and the tool body of the side punching mechanism, avoid economic losses caused by frequent damage and adverse effects on normal production;

(3) Improve the conveying conditions of pick-and-place parts on the production line, and ensure stable parts positioning, increase production tempo, and improve production efficiency.

Description of drawings

The above and other features, properties and advantages of the present invention will become more apparent from the following description in conjunction with the accompanying drawings and embodiments, in which the same reference numerals represent the same features throughout, wherein:

Fig. 1 is the schematic diagram of hook punching mechanism in the prior art;

Fig. 2 is a schematic diagram of a horizontal side impact mechanism in the prior art;

Fig. 3 is an embodiment of the oblique punching die structure of the automobile sheet metal stamping part of the present invention, and the automobile sheet metal stamping part in this embodiment is a perspective view of a rear cover plate workpiece of a passenger car;

Fig. 4 is the view that Fig. 3 is observed from the rear of the car;

Fig. 5 is the observation view of Fig. 3 automobile rear cover plate workpiece in the observation direction of mold schematic diagram of the present invention;

Fig. 6 is a structural diagram of an embodiment of the oblique punching die structure of the present invention, and simultaneously shows the first stage of the four stages of the punching method of the present invention: the die is opened and the stamping parts are placed;

Fig. 7 is the second stage of the four stages of the punching method of the present invention: the mold is closed, the schematic diagram of the punching state;

Fig. 8 is a partially enlarged view of the punching part in Fig. 7;

Fig. 9 is the third stage of the four stages of the punching method of the present invention: the punching is completed and the mold is opened;

Fig. 10 is the fourth stage of the four stages of the punching method of the present invention: a schematic diagram of the state of ejecting waste and taking out stamping parts;

Fig. 11 is an embodiment of the oblique punching die structure of the present invention, a schematic diagram of the assembly and structure of the ejector rod using limit bolts.

In the figure, 1-Second slider mechanism, 1a-A slider, 1b-B slider, 1c-C slider, 2-Punch slider guide plate, 3-Blank spring on side, 4-Punching punch, 5- side pressing plate, 6- ejector pin, 7- ejector pin, 8- punching die, 9- return spring, 10- ejection rod, 11- waste sliding plate, 12- base, 13 -block, 14-die slider guide plate, 15-first slider mechanism, 15d-D slider, 15e-E slider, 16-upper binder plate, 17-workpiece, a-long side, b- Short side, c-bend side, 18-limit bolt, 19-scrap.

21-upper die, 22-horizontal side impact mechanism.

31 - upper die, 32 - punching mechanism, 32a - punching parts, 32b - driving device of punching mechanism.

detailed description

The structure and punching method of the present invention will be further described in detail below in conjunction with the accompanying drawings.

An oblique punching die structure for automobile sheet metal stamping parts,

The oblique punching die mechanism includes a first slider mechanism 15 and a second slider mechanism 1, the first slider mechanism 15 is a slider mechanism that moves horizontally, and the second slider mechanism 1 is a slider that moves obliquely mechanism, the first slider mechanism 15 and the working surface of the second slider mechanism 1 are arranged opposite to each other;

The first slider mechanism 15 is provided with a punching die 8, the second slider mechanism 1 is provided with a punching punch 4, and the punching direction of the punching die 8 is consistent with the punching punch 4;

A material withdrawal rod 10, the material withdrawal rod 10 is connected with the first slider mechanism through the limit unit and the return spring 9;

A stopper 13, said stopper 13 is fixedly connected on the stationary base 12;

During the movement of the first slider mechanism 15 away from the second slider mechanism 1, its ejection rod 10 contacts the stopper 13, squeezes the return spring 9, and the end of the ejection rod 10 moves outwards and stretches out the punch. The cavity of the hole die 8;

The first slider mechanism 15 and the second slider mechanism 1 are the lower mold part of the oblique punching die mechanism. When the upper and lower molds are closed, the first slider mechanism 15 and the second slider mechanism The mechanism 1 is closed, and when the upper and lower molds are opened, the first slider mechanism 15 and the second slider mechanism 1 are separated.

As a specific implementation example, the section of the stamped part 17 is n-shaped with a long side, the long side a is a large panel, the short side b is a punched plate, and the middle is a bent side c, similar to the rear cover of a car or a passenger car Component.

The second slider mechanism 1 includes an inclined upward guide plate 2, and the punching punch 4 is arranged on the inclined upward guide plate 2;

The upper surface of the first slider mechanism 15 is the rest surface of the long side a of the large panel of the stamping part 17,

The length of the punching die 8 and the retracting rod 10 to the tail is less than the length of the bending edge c of the stamping part 17;

When the first slider mechanism 15 and the second slider mechanism 1 are closed, the punching punch 4 and the punching die 8 merge, the short side b of the stamping part 17 is clamped therebetween, and the punching die 8 is against the stamping part 17 The inner wall of the bent edge c.

A better embodiment is that, when the stamping part 17 is placed, the inwardly bent port of the short side b maintains a horizontal distance d from the outwardly extending end of the punching die 8, and the length of d is 5-10 mm. Keep such a distance to facilitate the placement of the stamping part 17 when punching, and also not to damage the tip of the stamping part 17 and the punching die 8 .

A preferred embodiment is that the contact surface of the stripping rod 10 and the stopper 13 is a vertical surface, or a surface forming an angle with the vertical, and the angle formed between the punching direction of the mold and the horizontal direction is α, the angle between the contact surface and the vertical is smaller than α/2. Selecting the vertical surface is convenient for design and manufacture, but in special cases, according to the needs or limitations of the occasion, the included angle configuration of the technical solution can also be used to achieve the purpose of the present invention.

A preferred embodiment is to open a through hole at the tail of the stripping rod 10 that is consistent with the moving direction of the stripping rod 10, and insert a stop bolt 18 fixed on the punching die 8 into the through hole, and the stop bolt 18 The bolt head of 18 limits ejector bar 10 and ejects to afterbody. This solution is one of the options for restricting ejection of the ejection rod 10 to the rear, and has a simple structure, convenient assembly and reliable use.

A preferred embodiment is that the top of the punching punch 4 is also provided with a side binder 5 supported by a side binder spring 3 , and a punch hole matching the punch is provided on the side binder 5 . This is beneficial to press the stamping part 17, which is beneficial to stabilizing the punching operation.

A preferred embodiment is that the ejector pins 6 and 7 are arranged on the protruding end faces of the punching punch 4 and/or the stripping rod 10 . This scheme can make the waste material 19 unlikely to be taken out by the punching punch 4 after punching, so that the waste material 19 is unlikely to be pushed out by the ejector rod 10 and brought back.

The specific implementation method may be that the second slider mechanism 1 also includes an A slider 1a that moves up and down, a B slider 1b that is converted into a horizontal movement through an inclined plane, and a C slider 1c that is converted into an oblique movement through a vertical plane Composition; the first slider mechanism 15 also includes a D slider 15d that moves up and down, which is converted into an E slider 15e that moves horizontally through a slope. This structure facilitates the simple, direct and reliable transmission of power by the second slider mechanism 1 in the required direction, and also facilitates the direct transmission of power by the first slider mechanism 15 in the required direction.

In addition, the punching method of the oblique punching die structure of the automobile sheet metal stamping parts adopts this technical solution in four stages,

The first stage: the mold is opened and the stamping is placed

The upper binder plate is in the open state of the top dead center of the press with the upper die, the punching die 8 installed on the first slider mechanism 15 and the punch punch 4 installed on the second slider mechanism 1 are separated from each other, and the stopper 13 and the ejection rod 10 are in contact or non-contact state, and the end of the ejection rod 10 is placed in the cavity of the punching die 8 by the return spring 9 and the limit unit; the bending of the stamping part 17 The side c and the short side b are downward, and the long side a rests on the upper surface of the first slider mechanism 15;

Second stage: mold closing, punching

The upper mold and the upper binder plate move downward, the punching die 8 on the first slider mechanism 15 and the punching punch 4 installed on the second slider mechanism 1 move towards each other, and the punching punch 4 moves in the direction of the oblique upward guide plate 2 , the long side a of the stamping part 17 is located in the cavity between the upper die and the upper surface of the first slider mechanism 15, the punching die 8 is against the inner wall of the bending side c of the stamping part 17, and the short side b of the stamping part 17 Clamped between the cutting edge of the punching die 8 and the punching die 4, the upper die and the upper pressing plate continue to move downward, the punching die 4 punches holes, and the punching waste 19 is contained in the cavity of the punching die 8 ;

The third stage: the punching is completed and the mold is opened

The upper mold drives the upper binder plate to move upward together, the upper binder plate is disengaged from the stamping part 17, the punching die 8 on the first slider mechanism 15 and the punching punch 4 installed on the second slider mechanism 1 are separated from each other, The punching punch 4 leaves the stamping part 17, and the ejector rod 10 on the punching die 8 just touches the stopper 13;

The fourth stage: Ejection of scrap, removal of stamping parts

The punching die 8 continues to retreat, the ejector rod 10 on the punching die 8 presses the block 13, squeezes the return spring 9, the end of the ejector rod 10 moves outward, and the punching waste is ejected out of the punching recess. The die has 8 cavities, falls into the waste slide plate or the waste groove below, and takes out the stamping parts.

Although the present invention is disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention, all fall within the scope of protection defined by the claims of the present invention.

Claims (8)

1. the oblique punching die structure of a plates of automobile stamping parts, it is characterised in that:

Described oblique punching die mechanism includes the first slide block mechanism (15) and the second slide block mechanism (1), first slide block mechanism (15) is the slide block mechanism of horizontal movement, second slide block mechanism (1) is the slide block mechanism of oblique movement, and its first slide block mechanism (15) is oppositely arranged with the work surface of the second slide block mechanism (1)；

First slide block mechanism (15) is provided with punching concave die (8), second slide block mechanism (1) is provided with piercing punch (4), and the punching direction of described punching concave die (8) is consistent with piercing punch (4)；

One material returned bar (10), described material returned bar (10) is connected with the first slide block mechanism by position-limiting unit and back-moving spring (9)；

One block (13), described block (13) is fixedly connected on pedestal (12)；

Described first slide block mechanism (15) is in the motion leaving the second slide block mechanism (1), its material returned bar (10) contacts with block (13), pressed home spring (9), the end of material returned bar (10) is displaced outwardly stretching out the vestibule of punching concave die (8)；

Described first slide block mechanism (15) and the second slide block mechanism (1) are the part of the lower die of described oblique punching die mechanism, when upper and lower mould closure state, described first slide block mechanism (15) and the second slide block mechanism (1) close up, when upper and lower mould open mode, described first slide block mechanism (15) and the second slide block mechanism (1) separate；

Described stamping parts (17) cross section is the n shape on a long limit, and long limit (a) is big panel, and minor face (b) is punched-plate, and centre is bending edges (c)；

Described second slide block mechanism (1) includes that guide plate (2) obliquely, described piercing punch (4) are configured at obliquely on guide plate (2)；

The upper surface of described first slide block mechanism (15) be the big long limit (a) of panel of stamping parts (17) shelve face,

Punching concave die (8) is less than bending edges (c) length of stamping parts (17) together with the length that material returned bar (10) rearwardly exits；

When described first slide block mechanism (15) and the second slide block mechanism (1) close, piercing punch (4) merges with punching concave die (8), the minor face (b) of stamping parts (17) clamps therebetween, and punching concave die (8) props up bending edges (c) inwall of stamping parts (17).

The most oblique punching die structure of plates of automobile stamping parts, it is characterized in that: when described stamping parts (17) is placed, the port of minor face (b) inflection keeps d horizontal range, a length of 5 10mm of d with described punching concave die (8) overhanging end.

The most oblique punching die structure of plates of automobile stamping parts, it is characterized in that: the contact surface of described material returned bar (10) and block (13) is vertical, or with vertically form the face of an angle, if the punching direction of described mould and horizontal direction angle are α, then contact surface and the angle vertically formed are less than α/2.

The most oblique punching die structure of plates of automobile stamping parts, it is characterized in that: the afterbody described material returned bar (10) offers the through hole consistent with material returned bar (10) moving direction, inserting the caging bolt (18) being fixed in punching concave die (8) in through hole, the bolt head of caging bolt (18) limits material returned bar (10) and rearwardly ejects.

The most oblique punching die structure of plates of automobile stamping parts, it is characterized in that: the top of described piercing punch (4) also sets up the side pressure flitch (5) supported by lateral pressing flat spring (3), described side pressure flitch (5) is provided with the punch hole mated with punch.

The most oblique punching die structure of plates of automobile stamping parts, it is characterised in that: the end face that stretches out at described piercing punch (4) and/or material returned bar (10) also configures that bullet ejector pin (6,7).

The most oblique punching die structure of plates of automobile stamping parts, it is characterized in that: described second slide block mechanism (1) also includes the A slide block (1a) moved up and down, be converted to the B slide block (1b) moved horizontally through inclined-plane, and be converted to C slide block (1c) composition of oblique movement through vertical；First slide block mechanism (15) also includes the D slide block (15d) moved up and down, and the E slide block (15e) being converted to move horizontally through inclined-plane is constituted.

8. the hole-punching method of the oblique punching die structure of a plates of automobile stamping parts as claimed in claim 1, it is characterised in that: use the technical program to have four-stage,

First stage: mould is opened, place stamping parts

Upper holding pad is in the open mode of press top dead-centre with upper mold, the punching concave die (8) being arranged on the first slide block mechanism (15) and the piercing punch (4) being arranged on the second slide block mechanism (1) are separated from each other, block (13) is in material returned bar (10) and contacts or contactless state, and material returned bar (10) is made the end of material returned bar (10) be in the vestibule of punching concave die (8) by back-moving spring (9) and position-limiting unit；The bending edges (c) of stamping parts (17) and minor face (b) are downward, and long limit (a) is shelved on the upper surface of the first slide block mechanism (15)；

Second stage: mould closes, punching

Upper mold and upper holding pad move downward, punching concave die (8) on first slide block mechanism (15) and be arranged on the piercing punch (4) of the second slide block mechanism (1) and move towards, piercing punch (4) diagonally upper guide plate (2) direction is moved, the long limit (a) of stamping parts (17) is positioned at the cavity between upper mold and the first slide block mechanism (15) upper surface, punching concave die (8) props up bending edges (c) inwall of stamping parts (17), the minor face (b) of stamping parts (17) is held between the cutting edge of punching concave die (8) and piercing punch (4), upper mold and upper holding pad continue to move downward, piercing punch (4) punching, punched scrap (19) is contained in punching concave die (8) vestibule；

Phase III: punching terminates, open mould

Upper mold drives upper holding pad to move upwardly together, upper holding pad disengages stamping parts (17), punching concave die (8) on first slide block mechanism (15) and be arranged on the piercing punch (4) of the second slide block mechanism (1) and be separated from each other, piercing punch (4) leaves stamping parts (17), material returned bar (10) the just contact blocks (13) in punching concave die (8)；

Fourth stage: eject waste material, takes out stamping parts

Punching concave die (8) continues to retreat, material returned bar (10) compressing block (13) in punching concave die (8), pressed home spring (9), the end of material returned bar (10) is displaced outwardly, punched scrap (19) is ejected punching concave die (8) vestibule, fall on the waste sliding plate of lower section or in reject chute, take out stamping parts.