CN109092976B

CN109092976B - Female die for stamping thin plate

Info

Publication number: CN109092976B
Application number: CN201811127777.9A
Authority: CN
Inventors: 何旺君; 苏波; 凌常月; 邹捷波; 陈斌; 金齐齐; 聂慧萍; 汤雄江
Original assignee: AECC South Industry Co Ltd
Current assignee: AECC South Industry Co Ltd
Priority date: 2016-06-28
Filing date: 2016-06-28
Publication date: 2021-01-01
Anticipated expiration: 2036-06-28
Also published as: CN105921595B; CN109108151A; CN109108152B; CN109108152A; CN105921595A; CN109108151B; CN109092976A

Abstract

The invention provides a female die for sheet punching, which is used for overcoming the defect that a punch and the female die are easy to break and damage when a sheet material is punched at a high speed. According to the female die for stamping the thin plate, the inner surface of the punched through hole is designed into a structure with the annular groove, and a part of air can be reserved in the annular groove, so that the negative pressure state in the punched through hole is destroyed, the waste is effectively prevented from being brought into the female die again, the punch and the female die are prevented from being damaged by the waste in a clamping manner, the edge breaking phenomenon caused by the fact that the punch is adsorbed by the waste and is brought back to the working surface is effectively prevented, and the damage of the punch and the female die caused by the edge breaking is avoided.

Description

Female die for stamping thin plate

Technical Field

The invention relates to a die which can be used in the field of high-speed stamping, in particular to a female die which can be used for high-speed stamping of thin plates.

Background

In modern die production, to meet the demands of stamping parts, this is often done by increasing the stamping speed. In the high-speed press working of thin plates, the punch is often broken. Sometimes, the punched waste material can appear on the punching working surface, and the surface of the part is scratched. These conditions not only damage the die but also severely affect the stamping efficiency and part yield.

Disclosure of Invention

The technical problem underlying the present invention is to provide a matrix for sheet metal stamping that reduces or avoids the aforementioned problems.

Particularly, the invention provides an improved female die for sheet punching, which can effectively overcome the defect that a punch and a female die are easy to break and damage when a sheet material is punched at a high speed.

In order to solve the technical problems, the invention provides a female die for sheet punching, which is used for overcoming the defect that a punch and the female die are easy to break and damage when a sheet material is punched at a high speed.

Preferably, the inner surface of the punched through hole is a tapered surface expanding downward.

Preferably, the taper of the conical surface of the inner surface of the punched through hole is 2 to 5 degrees, preferably about 3 degrees.

Preferably, the width a of the annular groove is 0.2-1.0 mm.

Preferably, the average depth b of the annular groove is 0.2-1.0 mm.

Preferably, the height h from the uppermost end of the annular groove to the upper end cutting edge of the female die is 2-5 mm.

Preferably, the female die is circular, and the outer surface of the female die is a conical surface expanding downwards.

Preferably, the taper of the conical surface of the outer surface of the female die is 1 to 5 degrees, preferably about 2 degrees.

Preferably, the female die is removably disposed in a bore of a base.

According to the female die for stamping the thin plate, the inner surface of the punched through hole is designed into a structure with the annular groove, and a part of air can be reserved in the annular groove, so that the negative pressure state in the punched through hole is destroyed, the waste is effectively prevented from being brought into the female die again, the punch and the female die are prevented from being damaged by the waste in a clamping manner, the edge breaking phenomenon caused by the fact that the punch is adsorbed by the waste and is brought back to the working surface is effectively prevented, and the edge breaking damage of the punch and the female die caused by the phenomenon is avoided.

Drawings

The drawings are only for purposes of illustrating and explaining the present invention and are not to be construed as limiting the scope of the present invention. Wherein the content of the first and second substances,

FIG. 1 is a schematic cross-sectional view showing a sheet material blanked by a stamping die;

FIG. 2 shows a cross-sectional view of a female die for sheet stamping according to an embodiment of the present invention;

fig. 3 shows a cross-sectional view of a female die for sheet punching according to another embodiment of the present invention.

Detailed Description

In order to more clearly understand the technical features, objects, and effects of the present invention, embodiments of the present invention will now be described with reference to the accompanying drawings. Wherein like parts are given like reference numerals.

As described in the background art, in the high-speed press working of thin plates, the punch breakage phenomenon often occurs. This phenomenon is rarely observed in the case of press working at ordinary speed. Statistics show that when the thin plate part is punched at the high speed of 500 times/min and 800 times/min, the probability of punch breakage is 10-20 times lower than that when the same part is punched at the normal speed of 200 times/min, which is obviously a strange phenomenon. The breaking reason of the punch is searched by checking the die, and the punch is not the local edge breakage of the cutting edge; the general working abrasion can not cause fracture; if the punch is made of a material and is caused by internal stress in heat treatment, the phenomena of punch fracture and die edge chipping can only occur on an accidental site, but during high-speed blanking, particularly when thin and light parts are punched, after the punch is operated for a period of time. Obviously this is not a normal die wear, but rather a result of the punch hitting some foreign object during blanking, creating a great resistance.

Analyzed foreign matter generation, not caused by material drop from the die or part blank defects, the applicant judged that this is most likely due to scrap material from the punch returning to the punching zone, but why is the scrap material from the punch returning to the punching zone against gravity? By contrast, it is obvious and surprising to the skilled person that the applicant excluded the factor of magnetization of the material (the sheet material is an aluminium alloy, which is not likely to generate magnetism) and also the factor of tribostatic attraction (the aluminium alloy is a good conductor, and is not able to accumulate enough static electricity to generate an attraction force sufficient to overcome the weight of the scrap), and finally that the applicant accidentally judged that this could be due to aerodynamic factors.

As shown in fig. 1, which shows a schematic cross-sectional structure of a sheet material punched by a punching die, as shown in the figure, during high-speed punching, a punch 1 contacts with the sheet material 2 and then goes down into a die 3 to punch off a slug 4 and form a hole 5, during the process of descending the punch 1, the surface of the punch 1 is in close contact with the edge of the hole 5 of the sheet material 2, because the punching speed is very fast (up to 500 and 800 times/min), the gap between the surface of the punch 1 and the edge of the hole 5 is very small and cannot suck enough air from above, and the air in the die 3 is itself pushed down and rapidly exhausted by the punch 1 and the slug 4, so that during high-speed punching, the punch 1 enters the area 6 below the hole 5 to instantaneously form a negative pressure state.

Therefore, when the scrap 4 itself is made of a low-density aluminum alloy thin plate and has a small volume, its own weight is light, so that when the punch 1 is returned upward (the punching speed is high, the speed of the punch returning downward and then upward is high, and the conversion process is almost instantaneously completed), the scrap 4 is attracted to the bottom surface of the punch 1 by the negative pressure described above and moves upward together with the punch 1.

When the punch 1 is separated from the hole 5 upwards, the negative pressure state is eliminated, and the waste 4 is blocked by the edge of the hole 5 (the edge of the hole 5 always extends and deforms slightly so that the waste 4 is slightly larger than the area of the hole 5) and randomly falls into the female die 3. At this moment, the sheet material 2 moves to a new position, the punch 1 punches a new waste material downwards again and enters the die 3, the bottom of the punch 1 and the new waste material collide with the falling waste material 4, the waste material 4 can be punched out of the die 3 in most cases, but the waste material 4 can be extruded into the edge gap of the punch 1 and the die 3 to be clamped and damaged by the punch 1 and the die 3, or the waste material 4 can be sucked upwards together with a plurality of new waste materials and then is clamped into the edge gap of the punch 1 and the die 3 more easily, so that the punch and the die can be damaged quickly after the continuous high-speed punching for a period of time.

Through the above non-obvious and unexpected discovery, the invention provides an improved die for sheet punching, aiming at the problem that a punch and a die are easy to break edges when a sheet material is punched at high speed. Referring to fig. 2, there is shown a cross-sectional view of a die for sheet punching according to an embodiment of the present invention, wherein the die 3 for sheet punching according to the present invention can be used to overcome the defect that a punch and a die are easily chipped when a sheet-like material is punched at a high speed, and the die 3 has a punched through hole 31, which is different from the die of fig. 1 in that an annular groove 32 is formed around the inner surface of the punched through hole 31 in a direction perpendicular to the axial direction of the punched through hole 31, and the annular groove 32 is located above the lowest point of stroke of the punch 1.

The female die 3 for sheet punching of the present invention, in which the inner surface of the punched through hole 31 is designed to have the annular groove 32, has the advantages that when the punch 1 punches the sheet-like material 2, the punch 1 and the slug 4 discharge the air in the punched through hole 31 downward, but the annular groove 32 is perpendicular to the axial direction of the punched through hole 31, that is, perpendicular to the direction of the air flow in the punched through hole 31, so that a part of the air can be retained in the annular groove 32, and the retained air breaks the negative pressure state in the punched through hole 31, when the punch 1 carries the slug 4 downward through the annular groove 32 (the negative pressure still exists above the annular groove 32), the air in the annular groove 32 can instantly enter the contact surface between the punch 1 and the slug 4, and the negative pressure state is released, and when the punch 1 returns upward, the slug 4 is not sucked by the punch 1 to move upward, thereby effectively prevented that waste material 4 from being brought into die 3 again to avoid waste material 4 card to die to destroy drift 1 and die 3, effectively prevent because of the tipping phenomenon that the waste material adsorbs the drift and is brought back the working face and arouse, avoided drift, the die tipping damage that from this caused.

In addition, due to the existence of the annular groove 32, an extending space perpendicular to the axial direction is additionally provided in the punched through hole 31, so that when the waste 4 passes through the annular groove 32, the punching deformation state (shown in fig. 1) of the waste 4 can be fully restored to a straight state (shown in fig. 2), the waste 4 in an irregular shape is further prevented from being stuck in a gap between the punch 1 and the die 3, and the service life of the die is prolonged.

In another preferred embodiment, as shown in fig. 2, the inner surface of the punched through hole 31 is designed as a tapered surface expanding downward. The cutting edge in the form of the downward-enlarged conical surface can directly drop the punched waste or parts from the punched through hole 31, and the punched through hole 31 is larger downwards, so that the material is not easy to accumulate in the through hole, the pressure on the hole with small abrasion is small, and the cutting edge is particularly suitable for high-speed punching of the invention. Further, in a preferred embodiment, the taper of the conical surface of the inner surface of the punched through hole 31 is 2 to 5 degrees, preferably about 3 degrees, which is an angle range for easier blanking in high speed punching.

In addition, in order to effectively destroy the negative pressure state, relevant dimensional parameters of the annular groove 32 are also important, and in an optimal scheme, the optimal air retention effect is preferably obtained with the minimum processing amount, so that the negative pressure destruction effect can be obtained, and the processing cost can be saved. For example, it is preferable that the width a of the annular groove 32 is 0.2 to 1.0 mm. In another preferred embodiment, the average depth b of the annular groove 32 is 0.2-1.0 mm, and since the inner side surface where the annular groove 32 is disposed is inclined, the depths of the annular grooves 32 on the inner side surface are not all the same, and thus the preferred depth should be defined as the average depth.

Furthermore, the position of the annular groove 32 is also a ring which needs to be optimally arranged, that is, the annular groove 32 is not only arranged in the stroke range of the punch 1, but also the height h of the uppermost end of the annular groove 32 from the upper end cutting edge of the female die 3 is 2-5mm in another preferred embodiment, considering that the more the lower the stroke of the punch 1 is, the more the negative pressure is formed, and the more air is needed to completely break the negative pressure state.

In order to better prevent the generation of cracks and stress concentration, the upper and lower corners (301, 302) where the annular groove 32 and the punched through hole 31 intersect each other may be arc transition corners, for example, arc transition corners processed to have a radius of 0.1 mm.

Fig. 3 is a cross-sectional view showing a female die for sheet punching according to another embodiment of the present invention, in which the internal structure of the female die 3 in fig. 3 is identical to that in fig. 2, except that the female die 3 of this embodiment is designed in a circular ring shape, and the outer surface thereof is a tapered surface expanding downward. The advantage of this kind of design has designed into modular structure with die 3, after the die blade wearing and tearing only need with the annular die part change can, can effectively guarantee the part size. In addition, the outer surface of the conical surface form which is expanded downwards is adopted, so that the cutting edge of the female die can be quickly replaced after being worn, namely, the female die module in the conical surface form can be detachably arranged in a hole of the base 10, the female die module can be conveniently detached from the base 10 after being damaged, the conical surface form can prevent the female die from being deformed and clamped in the hole of the base 10, and the detachment time is saved. On the other hand, with the die structure of fig. 3, there is also a certain connection with the punched through holes 31 of the conical surface form, that is, in the above embodiment, the taper of the tapered surface of the inner surface of the punched through hole 31 is 2 to 5 degrees, preferably about 3 degrees, although the angle range is easier for blanking in high-speed blanking, the angle range is much larger than the angle (generally, the cylindrical surface has no taper, the taper formed by tolerance is generally less than 0.5 degree) adopted by some female dies for sheet stamping, and under the condition of large-batch high-speed production, the abrasion speed of the cutting edge of the female die is high, therefore, in a preferred embodiment of the present invention, the taper of the conical surface of the outer surface of the circular female die 3 is designed to be 1 to 5 degrees, preferably about 2 degrees, so that the assembly and disassembly are more convenient and reliable than the conventional cylindrical surface, and the production efficiency is improved.

In conclusion, according to the female die for stamping the thin plate, the inner surface of the punched through hole is designed into a structure with the annular groove, and a part of air can be reserved in the annular groove, so that the negative pressure state in the punched through hole is destroyed, the waste is effectively prevented from being brought into the female die again, the punch and the female die are prevented from being damaged by the waste in a clamping manner, the edge breaking phenomenon caused by the fact that the punch is adsorbed by the waste and is brought back to the working surface is effectively prevented, and the damage of the punch and the female die caused by the edge breaking is avoided.

It should be appreciated by those of skill in the art that while the present invention has been described in terms of several embodiments, not every embodiment includes only a single embodiment. The description is given for clearness of understanding only, and it is to be understood that all matters in the embodiments are to be interpreted as including technical equivalents which are related to the embodiments and which are combined with each other to illustrate the scope of the present invention.

The above description is only an exemplary embodiment of the present invention, and is not intended to limit the scope of the present invention. Any equivalent alterations, modifications and combinations can be made by those skilled in the art without departing from the spirit and principles of the invention.

Claims

1. The utility model provides a die for sheet metal punching press for overcome the easy tipping defect of drift, die when blanking sheet material at a high speed, die (3) have a blanking through-hole (31), its characterized in that centers on the internal surface of blanking through-hole (31) is formed with a perpendicular to annular groove (32) of the axis direction of blanking through-hole (31), annular groove (32) are located the stroke minimum top of drift (1), the conical surface that blanking through-hole (31) internal surface is expanding downwards, die (3) are ring shape, and its surface is the conical surface that enlarges downwards, annular groove (32) with two upper and lower corners (301, 302) that blanking through-hole (31) is crossing are circular arc transition angle, die (3) detachably sets up in the hole of a base (10), the surface of die (3) the tapering of conical surface is 1-5 degrees, when the punch (1) punches the thin plate material (2), the punch (1) and the waste (4) discharge air in the punched through hole (31) downwards, a part of air is reserved in the annular groove (32), and when the punch (1) carries the waste (4) to move downwards to pass through the annular groove (32), the air in the annular groove (32) instantly enters a contact surface between the punch (1) and the waste (4) to release a negative pressure state.

2. A die for sheet punching according to claim 1, wherein the width a of said annular groove (32) is 0.2 to 1.0 mm.

3. A die for sheet stamping according to claim 1, wherein the average depth b of the annular groove (32) is 0.2 to 1.0 mm.

4. A die for sheet punching according to claim 1, wherein the height h of the uppermost end of said annular groove (32) from the upper end cutting edge of said die (3) is 2-5 mm.

5. A matrix for sheet punching according to claim 1, characterized in that the taper of said conical surface of the outer surface of said matrix (3) is 2 degrees.