EP3112042B1 - Punching tool and method - Google Patents

Description

The invention relates to a punching tool, in particular a punching tool, which is used in a universal punching machine in which punching waste, also called punched slugs, are disposed of by a tool lower part.

To improve the economy of the stamping process, the cutting edges are extended on punching tools, so that in a single punching stroke a greater length of the workpiece can be processed. By extending the cutting edges in punching tools for universal punching machines but also extends the separated from a plate-shaped workpiece material.

If it allows the size of the separated material, it is usually discharged through an opening in a lower tool part. However, the size of this opening is limited by the size of the lower tool holder in connection with the structure of the lower tool part, so that it can not be increased arbitrarily. Therefore, it becomes more difficult to remove the separated material the longer it gets. There is then u.a. the risk that the separated material in the opening canted or jammed if its length is greater than the diameter of the opening.

document EP 2 662 160 A1 discloses a punching tool for nibbling according to the preamble of claim 1.

The invention is therefore based on the object to provide a punching tool and a method that eliminate the above disadvantage and allow an economical, reliable punching processing.

The object is achieved by a punching tool according to claim 1 and a method according to claim 8. Further developments of the invention are the subject of the dependent claims. According to one aspect of the invention, at least one cutting edge of the punch has a discontinuity adapted to separate the separated material into a plurality of parts in the same punch stroke in which a material is separated from the workpiece, such that a length dimension of the respective one separated pieces of material shorter. Thereby, the length of the cutting edge can be increased and thus the efficiency of the stamping process can be increased, without resulting in the problems of jamming or jamming of too long separated material parts in its removal.

The invention will now be described by way of example with reference to the accompanying drawings

The embodiments of the invention are in the Figures 2 and 6 shown. The remaining figures do not represent embodiments according to the invention.

Fig. 1a

eine teilweise geschnittene Seitenansicht eines Werkzeugoberteils und eines Werkzeugunterteils während eines Stanzhubs, bei dem ein Abschnitt von Schneidkanten einen Teil eines abzutrennenden Materials abteilt;

Fig. 1b

eine teilweise geschnittene Seitenansicht des Werkzeugoberteils und des Werkzeugunterteils von Fig. 1a nach einem vollendeten Stanzhub mit dem zerteilten abgetrennten Material;

Fig. 2

eine teilweise geschnittene Seitenansicht des Werkzeugoberteils und des Werkzeugunterteils nach einem vollendeten Stanzhub mit zerteiltem und verformtem abgetrennten Material;

Fig. 3a bis Fig. 3c

schematische Seitenansichten des Werkzeugoberteils mit stufenförmigen Übergängen und mit Abschnitten der Schneidkanten mit jeweils in einer Stanzrichtung konstantem Abstand zu einer Schneidkante des nicht gezeigten Werkzeugunterteils;

Fig. 4a und Fig. 4b

schematische Seitenansichten des Werkzeugoberteils mit stufenförmigen Übergängen und mit Abschnitten mit jeweils in der Stanzrichtung nicht konstantem Abstand zu der Schneidkante des nicht gezeigten Werkzeugunterteils;

Fig. 5a und Fig. 5b

schematische Seitenansichten des Werkzeugoberteils mit Knicken als Übergänge und mit Abschnitten mit jeweils in der Stanzrichtung nicht konstantem Abstand zu der Schneidkante des nicht gezeigten Werkzeugunterteils;

Fig. 6a

eine schematische Seitenansicht des Werkzeugoberteils mit einer Spitze als Übergang und mit Abschnitten mit in der Stanzrichtung jeweils nicht konstantem Abstand zu der Schneidkante des nicht gezeigten Werkzeugunterteils;

Fig. 6b

eine schematische Seitenansicht des Werkzeugoberteils mit einer Spitze als Übergangsstelle und mit Abschnitten mit einer konkaven Form;

Fig. 6c

eine schematische Seitenansicht des Werkzeugoberteils mit einer Spitze als Übergangsstelle und mit Abschnitten mit einer konvexen Form;

Fig. 7a

eine schematische Seitenansicht des Werkzeugoberteils mit Abschnitten mit stufenförmigen Übergangsstellen und mit jeweils konstantem Abstand in der Stanzrichtung zu der Schneidkante des nicht gezeigten Werkzeugunterteils und mit zusätzlichen weiteren Schneidkanten;

Fig. 7b

eine schematische Vorderansicht des Werkzeugoberteils von Fig. 7a.

In particular, show

Fig. 1a

a partially sectioned side view of a tool top and a tool lower part during a punching stroke, wherein a portion of cutting edges divides a part of a material to be separated;

Fig. 1b

a partially sectioned side view of the upper tool part and the lower tool part of Fig. 1a after a completed punching stroke with the cut separated material;

Fig. 2

a partially sectioned side view of the tool top and the tool base after a completed punching stroke with divided and deformed separated material;

Fig. 3a to Fig. 3c

schematic side views of the upper tool part with step-shaped transitions and with sections of the cutting edges, each in a punching direction constant distance to a cutting edge of the lower tool part, not shown;

Fig. 4a and Fig. 4b

schematic side views of the upper tool part with stepped transitions and with sections with each in the punching direction not constant distance to the cutting edge of the lower tool part, not shown;

Fig. 5a and Fig. 5b

schematic side views of the upper tool part with kinks as transitions and with sections with each in the punching direction not constant distance to the cutting edge of the lower tool part, not shown;

Fig. 6a

a schematic side view of the upper tool part with a tip as a transition and with sections with each in the punching direction not constant distance to the cutting edge of the lower die part, not shown;

Fig. 6b

a schematic side view of the tool shell with a tip as a transition point and with sections with a concave shape;

Fig. 6c

a schematic side view of the tool shell with a tip as a transition point and with sections with a convex shape;

Fig. 7a

a schematic side view of the upper tool part with sections with stepped transition points and at a constant distance in the punching direction to the cutting edge of the tool lower part, not shown, and with additional additional cutting edges;

Fig. 7b

a schematic front view of the upper tool part of Fig. 7a ,

In Fig. 1a is a partially sectioned side view of a tool upper part 1 and a lower tool part 2 of a punching tool shown. The upper tool part 1 and the lower tool part 2 are shown in a state mounted in the punching machine and have an axis 3. The upper tool part 1 and the lower tool part 2 are movable relative to each other along the axis 3.

The lower tool part 2 is received in a tool holder, not shown, and the punching machine has a discharge opening 10, can be disposed of by the separated material.

Fig. 1b shows the upper tool part 1 and the lower tool part 2 Fig. 1a after a completed punching stroke. Due to the disassembled state of the upper tool part 1 and the lower tool part 2 is an upper in this illustration To see cutting edge 6 of the upper tool part 1 and a lower cutting edge 7 of the lower tool part 2.

The upper cutting edge 6 defines an upper cutting surface 4 and the lower cutting edge 7 defines a lower cutting surface 5. The cutting edges 6, 7 are complementary to each other and have a required cutting gap.

The cutting surfaces 4, 5 are respectively at end faces of the tool upper part 1 and of the tool lower part 2 in the direction of the axis 3, i. in the punching direction, provided. The upper cutting surface 4 of the tool upper part 1 and the upper cutting edge 6 are divided along the cutting edge 6 into three sections 4a, 4b, 4c. As will be shown later, the upper cutting edge 6 may alternatively be divided into a different number of sections. However, at least two sections must be provided. Between the sections 4a, 4b, 4c, a transition point 8 is provided in each case. The transition point 8 has a discontinuity in the direction of the axis 3 along the upper cutting edge 6. Unsteadiness is an abrupt change in the upper cutting surface. Discontinuities are, as shown later, for example, a step (a jump), a kink or a peak.

Alternatively, the lower cutting surface 5 of the tool lower part 2 can have transition points 8. In this case, it is then necessary that the tool lower part 2 is provided with a sprung scraper or the punching machine with an active lower tool holder, which allows an axial movement of the tool lower part 2.

By the transition point 8 two of the sections 4a, 4b, 4c are separated. The upper cutting edge 6 and the lower Cutting edge 7 have in the sections 4a, 4b, 4c in the direction of the axis 3 in a respective predetermined position of the upper tool part 1 and the lower tool part 2 a distance A from each other. The distance A is in the in Fig. 1a and 1b shown embodiment within one of the sections 4a, 4b, 4c constant and increases along the cut edges 6, 7 alternately in stages or drops gradually.

In operation, after a positioning of a plate-shaped workpiece 9, for example a metal plate, a punching stroke of the tool upper part 1 is carried out in a punching position. In this case, during the punching stroke, first an inner region of a contour to be punched is stretched beyond its elastic limit or yield point by the section 4b with the smallest axial distance A between the upper cutting edge 6 and the lower cutting edge 7 until the material breaks and a segment 9a of a material to be separated through the discharge opening 10 falls down ( Fig. 1 ).

Upon further movement of the tool upper part 1 during the punching stroke, further segments 9b, 9c of the remaining material to be separated off are separated by the same mechanism and fall downwards through the discharge opening 10 (FIG. Fig. 2 ).

By dividing the separated material of the workpiece 9 into three parts, the separated material, the entire length dimension of which would be greater than a diameter of the failure opening 10, can be disposed of safely through the failure opening 10 without jamming or jamming.

The division of the punching slugs on several levels during a punching stroke basically results from the speed of the punching stroke Punching strokes and the resistance of the material or material to be punched. In the case where the resistance of the material to be punched is relatively small, a resulting punching slug is partially deformed before being diced, thereby forming an enveloping circle (meaning the projected length of the punching slug, when taking the bent punching slug projected onto an underlying level) of the Butzens to be disposed is smaller than the failure opening 10 of the punching machine. However, it is not mandatory that the transitions 8 have an exact discontinuity, but slight deviations from an ideal jump, an ideal tip or an ideal kink is possible, as long as the resistance of the material to be punched or material in conjunction with the speed of Punching strokes allows a division.

In Fig. 2 is a partially sectioned side view of the upper tool part 1 shown in another embodiment and the lower tool part 2 after the completed punching stroke.

The upper tool part 1 has in this embodiment, a transition point 8, which is formed as a tip. The lower tool part 2 remains unchanged from the previous embodiment.

In operation, in this embodiment, as in FIG Fig. 1a, 1b , one segment punched out in advance. Here, during the punching stroke, the material is first stretched by the tip against its residual stress beyond its elastic limit or yield point until it is deformed or cut, and then the material to be separated is moved through the cutting edge 6 in the sections as the tool head 1 advances in the same punching stroke 4a, 4b separated from the workpiece 9, it also is divided into the two segments 9a, 9b. Again, the separated material, whose entire length dimension is greater than a diameter of the failure opening 10, disposed of by dividing into the two segments 9a and 9b safely through the outlet opening 10 without jamming or tilting.

The cutting edges 6 of the sections 4a, 4b adjoining the tip-formed transition point 8 have a spacing A from the second cutting edge 7 in the punching direction which is not constant within the sections 4a, 4b. The distance A increases in a non-linear manner and the cutting edges 6 in the sections 4a, 4b have a concave shape in this embodiment. Due to the non-linear change (concave shape), the segments 9a, 9b are additionally deformed so that a length dimension, ie a projected length, of the separated material is further shortened. As a result, a saving of transition points 8 or a further enlargement of the cutting edges 4, 5 is possible, without increasing the risk of jamming or jamming in an opening of the tool lower part 2 or the outlet opening 10.

In the FIGS. 3 to 6 Transition points 8 and arrangements of sections 4a, 4b, 4c, 4d, 4e are shown in various embodiments. The lower cutting edge 7 of the lower tool part 2 is not shown here. With axial distance, the axial distance to this lower cutting edge 7 is meant.

Fig. 3a to 3c each show a tool upper part 1, the upper cutting surface 4 and upper cutting edge 6 by steps (jumps) as transition points 8 in the three sections 4a, 4b, 4c and the five sections 4a, 4b, 4c, 4d, 4e is divided.

The distance A in the punching direction of the upper cutting edge 6 in the sections 4a, 4b, 4c (4d, 4e) rises in the Fig. 3a and 3b in a direction along the upper cutting edge 6 in each case from the center in stages. Alternatively, the distances may also increase gradually starting from one end of the cutting edge 6.

In Fig. 3c the distance in the punching direction of the upper cutting edge 6 of the tool upper part 1 in the sections 4a, 4b, 4c, 4d, 4e along the cutting edge 6 is gradually increasing and decreasing. The distance A of the cutting edge 6 from one of the sections 4a, 4b, 4c, 4d, 4e in this embodiment is identical to the distance A of the cutting edge 6 of the next but one section 4a, 4b, 4c, 4d, 4e. In an alternative embodiment, the distance A of the cutting edge 6 of the next but one section 4a, 4b, 4c, 4d, 4e is not identical.

In Fig. 4a and 4b the upper cutting surface 4 and the upper cutting edge 6 of the tool upper part 1, the portions 4a, 4b, 4c ( Fig. 4a ) or the sections 4a, 4c ( Fig. 4b ), in which the distance A of the upper cutting edge 6 to the lower cutting edge 7 is not constant. In this case, a sawtooth shape along the cutting edges is formed by the shape of the sections.

Also in Fig. 5a and 5b the distance A in the punching direction between the upper cutting edge 6 of the tool upper part 1 and the lower cutting edge 7 within the sections 4a, 4b, 4c, 4d is not constant. The transition points 8 are formed here as discontinuities by kinks.

In Fig. 6a to 6c is, as well as in Fig. 2 , the transition point 8 as a discontinuity of the cutting surface 4 of the upper tool part 1 in formed the shape of the tip. The distance A in the punching direction between the upper cutting edge 6 and the lower cutting edge 7 is not constant within the individual portions 4a, 4b adjacent to the tip.

In Fig. 6a the distance A in the punching direction of the upper cutting edge 6 from the lower cutting edge 7, starting from the tip, increases linearly along the upper cutting edge 6 within the portions 4a, 4b.

In Fig. 6b and 6c the distance A does not increase linearly. Again, how to Fig. 2 described by the concave in the punching direction ( Fig. 6b ) or convex shape ( Fig. 6c ) the separated material in addition to the dicing also deformed, whereby the length dimension is additionally reduced.

By the transition points 8 in the form of a discontinuity, mainly at a transition point 8, which is designed as a stage, a different edge indentation may be present, so that in the punching process no clean edge can be produced.

In Fig. 7a and 7a By way of example, a punching tool is shown which, in addition to the upper cutting edge 6 and the lower cutting edge not shown here, has a further upper cutting edge 11 on the upper die 1 and a further lower cutting edge (not shown) on the lower tool part 2, each with a continuous course.

The further upper cutting edge 11 and the further lower cutting edge are set back in the axial direction with respect to the upper cutting edge 6 and the lower cutting edge 7, respectively and, like in Fig. 7b shown, laterally adjacent to the upper and lower cutting edge 6, 7 outside the upper cutting surface 4 on the upper die 1, and also arranged laterally outside the lower cutting surface 5 on the lower tool part 2. The lateral offset between the upper cutting edge 6 and further upper cutting edge 11 or between the lower cutting edge 7 and the further lower cutting edge is a few tenths of a millimeter. The lateral offset may alternatively have a different dimension, provided that the function of separating or deforming the separated material and a uniform cut are made possible.

In operation, in this embodiment, in one and the same punch stroke in a first step, such as Fig. 1 described, a part of the material to be separated by the upper cutting edge 6 and lower cutting edge 7 separated, and divided and possibly deformed, but a different edge indentation can occur. In a continuation of the same punching stroke breaks in a second section through the further upper continuous cutting edge 11 and the further lower continuous cutting edge another part of the material to be separated, namely remaining material residues between a pre-punching contour and a finished punching contour, and a punching edge is formed with a continuous edge feed. The material separated from the workpiece 9 is divided into the segments 9a, 9b, 9c. Since a width of the remaining material remnants is only very small, they are also divided, and the segments 9a, 9b, 9c with the respective material residues can be disposed of through the discharge opening 10 without the risk of jamming or tilting.

The different embodiments can be combined with each other.

Claims (10)

1. Punching tool for a punching machine for punching a plate-shaped workpiece (9) comprising
   an upper tool part (1) and a lower tool part (2) being movable relatively to each other in a punching direction in a state when the punching tool is mounted in the punching machine, wherein
   the upper tool part (1) comprises an upper cutting edge (6) and the lower tool part (2) comprises a lower cutting edge (7) being complementary shaped to the upper cutting edge (6) and opposite thereto so that a material is cut off from the workpiece (9) by the cutting edges (6, 7) upon a punching stroke, and,
   in the state when the punching tool is mounted in the punching machine in a predetermined positon of the upper tool part (1) and the lower tool part (2), the upper cutting edge (6) and the lower cutting edge (7) comprise, along their course, a varying distance (A) in the punching direction, wherein
   the upper cutting edge (6) and/or the lower cutting edge (7) are/is partitioned along its course in at least two portions (4a, 4b, 4c, 4d, 4e) at at least one transition spot (8),
   the transition spot (8) comprises, relatively to the respectively adjacent portions in the punching direction between two adjacent portions (4a, 4b, 4c, 4d, 4e), a discontinuity, and
   the transition spot (8) is a tip,
   wherein the distance (A) in the portions (4a, 4b, 4c, 4d, 4e) adjacent to the tip is not constant,
   characterized in that the transition spot (8) is adapted such that the material (9a, 9b, 9c) cut off from the workpiece (9) is divided into several individual parts in the same punching stroke by the discontinuity at the transition spot.
2. Punching tool according to claim 1, wherein the distance (A) at the transition spot (8) is smaller than in at least one of the adjacent portions.
3. Punching tool according to claim 1 or 2, wherein the distance (A) in the respectively adjacent portion (4a, 4b, 4c, 4d, 4e) linearly increases along the cutting edge (6, 7).
4. Punching tool according to claim 1 or 2, wherein the distance (A) in the portion (4a, 4b, 4c, 4d, 4e) increases different from linear along the cutting edge (6, 7) so that a linear dimension of the material (9a, 9b) cut off from the workpiece (9) is reduced by deforming in the punching direction by the cutting edge (6, 7) in the same punching stroke.
5. Punching tool according to claim 4, wherein the cutting edge (6, 7) comprises a convex shape in the punching direction in the portion (4a, 4b, 4c, 4d, 4e).
6. Punching tool according to claim 4, wherein the cutting edge (6, 7) comprises a concave shape in the punching direction in the portion (4a, 4b, 4c, 4d, 4e).
7. Punching tool according to one of the preceding claims, wherein, in the punching direction, the upper tool part (1) comprises an upper cutting face (4) and the lower tool part comprises a lower cutting face (5), respectively, and the upper cutting edge (6) delimits the upper cutting face (4) and the lower cutting edge (7) delimits the lower cutting face (5),
   the upper tool part (1) comprises a further upper cutting edge (11) and the lower tool part (2) comprises a further lower cutting edge, and
   the further upper cutting edge (11) and the further lower cutting edge comprise a steady course and, in the punching direction, they are provided being set back respectively opposite to the punching direction with respect to the upper cutting edge (6) and the lower cutting edge (7) and being laterally outside from the upper and lower cutting faces (4, 5) beside the upper and lower cutting edges (6, 7) to perform a second cut during the same punching stroke of the punching machine.
8. Method for cutting off material from a workpiece and for reducing a linear dimension of the material (9a, 9b, 9c) cut off from the workpiece (9) by performing a punching stroke by a punching tool according to one of the claims 1 to 7 whereby, in the same punching stroke, a part of a material to be cut off is cut off by a discontinuous cutting edge (6) and the linear dimension is reduced by dividing the cut off material (9a, 9b, 9c) by the discontinuity at the tip where the material to be cut off is firstly stretched beyond its elasticity limit or its yield strength until it is deformed or divided and, then, the material to be cut off is cut off from the workpiece by the cutting edges in the portions (4a, 4b) adjacent to the tip upon continuing the punching stroke, whereby it is divided in two segments (9a, 9b).
9. Method according to claim 8 with a punching tool according to one of the claims 4 to 6, wherein the linear dimension is further reduced by deforming the cut off material (9a, 9b, 9c).
10. Method according to claim 8 or 9 with a punching tool according to claim 7, wherein a further part of the material to be cut off is cut off by a steady cutting edge (11) in the same punching stroke subsequently.

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