EP1604751A1 - Punching device and punch therefor - Google Patents

Abstract

A perforating press, e.g. for perforating green sheets in the production of ceramic substrates, has a pattern of thin needles (21) held in a press block with the pointed ends passing through the sheets and into a set of socket holes. The top ends of the needles have waisted sections (24) onto which are secured shrink fit sleeves (22) to provide a thrust surface to drive the thin needles. The waisted profile can be prepared in a variety of processes and with a variety of profiles. The sleeve can be metal or plastic and can be fitted by a cold or hot process. The needles are replaceable when worn.

Description

The invention relates to a punching device and its Punch. In particular, the invention relates to a stamping device and a punch for unburned areal Ceramic substrates, in particular so-called green Sheets.

Green sheets usually have to be produced during their manufacture be provided with a number of small holes later serve for example for the passage of conductors, the be applied to the ceramic substrates. It is about thereby relatively small holes of significantly less than one Millimeters in diameter, with such holes in large numbers are to be attached. The punching device has a corresponding large number of punches on. The punches are provided with heads, in a holding device, for example a holding plate, are held to with this in the shaft longitudinal direction, i. e.g. to be moved up and down.

A similar punching device is for example off EP 0 354 152 B1. The punches will be here moved by magnetic drives. These punches are also each with a head attached to the elongated shaft the punch is attached.

The punches are in their activity of a high exposed to abrasive stress. You must therefore from one designed according wear-resistant hard material be. They are therefore made of an elongated needle-like Body trained, in which usually other Material existing head to approach the top plate or other Drives is subsequently recognized.

For example, as known from US Pat. No. 3,974,728 the working part of a punch also in one with a punch Head fitted body used and this example be attached by adhesive. However, this sets a relatively expensive preparation ahead. After stamping be regarded as wearing parts, it is therefore desirable to produce them as quickly, easily and inexpensively to be able to, with the quality suffered no loss may. However, the quality is determined by the straightness, i.e. determines the precision of the punch. splices between a cylindrical drive body and a cylindrical one Working part are critical here.

It is also known from US Pat. No. 4,700,601 to use punches, which are intended for punching paper, with a To provide plastic head. For this purpose, the metal existing Punch on an annular groove. The one with the ring groove provided area is then covered with a cylindrical plastic body molded around, with the plastic partially in the Ring groove flows and thus a positive connection between the head and the stamp manufactures.

The punches for green sheets can usually not be provided with artificial heads. Due to the low Diameter of the shanks of the punches arise usually also no sufficiently durable form-fitting connections between a plastic head and the punch.

On this basis, it is an object of the invention to provide a Punch for a green-sheet punching device and a to create appropriate punching device, wherein the punches be easy and inexpensive to manufacture and thereby high quality standards.

Der erfindungsgemäße Stanzstempel weist einen Stempelschaft auf, der an einem Ende einen Kopf und am gegenüberliegenden Ende ein Arbeitsteil aufweist. Am Kopfende ist der Stempelschaft an seiner Mantelfläche mit wenigstens einer Ausnehmung versehen. Im Bereich der Ausnehmung sitzt ein ringförmiger Kopf, der einen in die Ausnehmung greifenden und den Kopf dadurch formschlüssig an dem Schaft sichernden Vorsprung aufweist. Dieser Vorsprung ist durch plastische Verformung des Kopfs erzeugt. Dies hat in der Regel zur Folge, dass das Material des Kopfs unter einer gewissen Vorspannung an dem Schaft anliegt. Dies gilt insbesondere wenn der Kopf aus einem geeigneten Metall, wie Stahl, Messing oder Aluminium, gefertigt ist. Anders als eine Kunststoffumspritzung, die sich schon in Folge von natürlicher Schrumpfung oder Schwindung des Kunststoffs etwas lösen kann, ist hier ein fester Sitz gesichert.

This object is achieved with the punch of claim 1 and the punching device according to claim 20:

The punch according to the invention has a punch shaft which has a head at one end and a working part at the opposite end. At the head of the stamp shaft is provided on its lateral surface with at least one recess. In the region of the recess sits an annular head having a recess in the recess and the head thereby positively locking on the shaft projection. This projection is created by plastic deformation of the head. This usually has the consequence that the material of the head rests against the shaft under a certain bias. This is especially true when the head is made of a suitable metal such as steel, brass or aluminum. Unlike a Kunststoffumspritzung, which can be solved as a result of natural shrinkage or shrinkage of the plastic something, a tight fit is secured here.

The production of the punch is very short Cycle times possible. It just has to be a head blank over pushed the shaft and then by a suitable deformation process for plastic deformation of the head on the Shank to be secured. The manufacturing processes with those this can be realized, for example, embossing, pressing, Rolling, hammering or other non-cutting methods Shaping. Is the head of a low-melting If necessary, he could also use metal in a casting process, for example in a die-casting process. However, this is considered less advantageous because the associated effort is higher.

The projection securing the head to the shaft is like mentioned, preferably by plastic deformation of the head blank generated. This is done on the head during production formed a depression. Preferably, the shape corresponds the recess of the shape of the recess provided on the shaft. If this example, an annular bead, is at the otherwise cylindrical outer circumferential surface of the head preferably formed an annular recess. This will the required plastic deformation of the head to a minimum limited. However, it is also possible, in addition a restraining or deforming pressure, e.g. in Form axial direction on the head to the radially after directed inward flow of the head material into the recess of the stem.

The recess of the shaft preferably has a waisted Shape up. Sharp edges are avoided to cancel of the slender shaft in the region of the recess not to favor. Preferably, the recess is through a annular concavely curved ring surface bounded, the edged and is formed without heel. The depression then has a adapted form.

The head preferably sits at the end of the shaft, which is opposite to the working part. He prefers sitting at the end of the shaft, leaving the shaft end with the head closes or slightly protrudes from the head. It has proved to be advantageous, the recess and accordingly the protrusion of the recess reaching into the recess Head close to the shaft end to order. Thus, the Passage of the head at the remote from the shaft end Side on a cylindrical guide portion which on the Head attacking tilting moments on the shaft transfers or on this supported without the weakened by the recess Zone of the shaft. This is especially true if the Recess of the shaft, as is preferably the case to the upper, the shank end facing the plan surface of the head concludes.

The head preferably has before its plastic deformation a through hole whose width is slightly larger than that of the shaft, so that the shaft is low Game can be introduced into the head. After the plastic Deformation, the head sits without play on the shaft. Preferably, the through-hole of the head is on whole Length has been narrowed so far that the head is gapless on the Shaft is seated.

In addition to the positive locking of the head on the shaft a cohesive connection can be provided become. This can for example be an adhesive bond be. The advantage of this measure is for example in the easy application of the adhesive before the plastic Deformation process housed in the recess of the shaft can be.

It is also possible that the adhesive for positive locking Securing the head on the shaft after the plastic Deformation of the head is introduced by capillary action retracts between stem and head after application.

Notwithstanding the embodiments described above can instead of a recess also several recesses be provided, in which case the above statements apply accordingly. The recesses can be around the whole Scope of the shaft around or just over a part extend and axially spaced from each other or be arranged at the same height.

Further advantageous details of embodiments The invention are the subject of the drawing, the description and / or claims.

Figur 1

eine Stanzeinrichtung für Green Sheets in einer schematisierten perspektivischen Prinzipdarstellung,

Figur 2

die Stanzeinrichtung nach Figur 1 in einer längs geschnittenen ausschnittsweisen schematisierten Darstellung,

Figur 3

einen Stempel vor Befestigung seines Kopfs an seinem Schaft in längs geschnittener Prinzipdarstellung,

Figur 4

den Stempel mit fest auf seinem Schaft sitzenden Kopf,

Figur 5 und 6

einen Stempel jeweils vor und nach der Befestigung seines Kopfs auf dem Schaft in einer alternativen Ausführungsform in längs geschnittener Darstellung,

Figur 7 und 8

einen Stempel jeweils vor und nach der Befestigung seines Kopfs auf dem Schaft in einer alternativen weiteren Ausführungsform in längs geschnittener Darstellung und

Figur 9 und 10

einen Stanzstempel jeweils vor und nach der Befestigung seines Kopfs auf dem Schaft in einer alternativen fortentwickelten Ausführungsform in längs geschnittener Darstellung.

In the drawings, embodiments of the invention are illustrated. Show it:

FIG. 1

a punching device for green sheets in a schematic perspective schematic representation,

FIG. 2

1 shows the punching device according to FIG. 1 in a longitudinal sectioned schematized representation,

FIG. 3

a stamp before attachment of his head to his shaft in longitudinally cut schematic diagram,

FIG. 4

the stamp with his head firmly seated on his shaft,

FIGS. 5 and 6

a punch in each case before and after the attachment of its head on the shaft in an alternative embodiment in longitudinal section,

FIGS. 7 and 8

a punch in each case before and after the attachment of his head on the shaft in an alternative further embodiment in longitudinal sectional view and

FIGS. 9 and 10

a punch in each case before and after the attachment of his head on the shaft in an alternative developed embodiment in longitudinal section.

In Figure 1, a punching tool 1 is illustrated, to a lower tool 2 and an upper tool 3 belong. The Upper tool 3 is by means of two guides 4, 5 on the lower tool 2 back and forth linearly reciprocating movable. The lower tool 2 contains a support plate or receiving device 6, formed in the punched holes 7 are. The punch holes 7 are numerous in the platen 6 and formed in such places, where in one on the Platen 6 applied green sheet (unfired ceramic substrate) Holes are to be punched out. These are on the upper tool 3 punch 8 arranged on the lower tool 2 and point above the support plate 6 ends. The punches 8 can dip into the punch holes 7 when they are moved down. Above the platen 6 is to guide the punch 8 and hold down the on the platen lying Green Sheets a hold-down plate 9, which have been omitted in Figure 1 is to look at the punch 8 and the recording device 6 free.

The upper tool 3 together with hold-down plate 9 go out Figure 2 shows. The hold-down plate 9 is above the Platen 6 regardless of the punching movement of the stamp 8 arranged vertically movable and defined with this one Gap 11 for receiving a not illustrated green Sheets. The hold-down plate 9 is connected to the upper tool. 3 connected or part of the same and movable with this. One Arrow 12 indicates the direction of movement of the upper tool 3.

The punch 8 is in the hold-down plate 9 by at least a guide bush 13 and possibly another at the Hold-down plate 9 provided guide bush 14 axially guided. In this case, the punch 8 at its lower, in the Guide bush 14 projecting part preferably a multi-stepped Profile and a slim working part 15. this is associated with the punch hole 7, which in one of the receiving device 6 held sleeve 16 is formed.

The punch 8 is in an upper holding device 17 held axially immovable, which serves to the stamp 8 to give its axial movement. The holding device 17 belongs to the upper tool 3. It can basically be different Be formed manner. It is essential that it has a drive element 18, in the present embodiment is designed as a plate and serves to move the punch 8 down. Next belongs to the Holding device 17, a return element 19, in the present Embodiment is designed as a plate and to serves the punch 8 against its punching direction, i. of the Recording device 6 to move away. The driving element 18 and the return member 19 forming plates can, as represented, firmly against each other or against each other be designed to be movable. You can by spring means against each other be curious and the stamp 8 between each other Clamp. It may also not illustrated spring means provided between the punch 8 and the holding device 17 be.

The punch 8 has at least one preferably cylindrical elongated shaft 21 and one preferably also essentially cylindrical head 22, the form-fitting connected to each other. There are the Shank 21 and the head 22 preferably made of different Metals. The shaft 21 is in terms of its Stan properties optimized. In particular, at its working part 15 subject he suffered a considerable amount of wear, in particular in the area of its cutting edges. This is by a suitable Material choice encountered. The shaft 21 thus exists made of a suitable steel. The head 22, however, serves only to the required driving forces in the stamp. 8 initiate. On oversized hardness or wear resistance it does not matter. He is thus as a separate part from a suitable metal, such as a good one deformable steel or other metals and attached to the shaft 21. This is in detail in the Figures 3 and 4 illustrated. The shaft 21 has for attachment of the head 22 a recess 23, for example in Shape of a shank 21 surrounding flat annular bead. This has, as Figure 3 illustrates, a waisted Shape up. The limiting annular surface 24 is edged and formed without a heel. The axial length of the annular surface 24 exceeds the depth of the recess 23 by far. The axial Length of the annular surface 24 also exceeds the largest diameter the annular surface 24 by far. Next, it has to be advantageous exposed, if the axial length also the circumference the ring surface 24 exceeds, as he in place with smallest diameter of the annular surface 24 is to measure.

The head 22 is made of an initially hollow cylindrical Blank 22 'is formed, which has a central through hole 25 has. The diameter of the through-hole is preferably slightly larger than the shaft diameter, so that the Blank 22 'pushed over the shaft 21 without difficulty can be. For attachment of the blank 22 'on the shaft 21 and thus for the formation of the head 22, the blank 22 ' deformed. This can be seen by comparing Figures 3 and 4. The head 22 is with one on its cylindrical Outer surface 26 provided around running recess 27, the by a radially inward compression of the head 22 has emerged. The recess 27 corresponds in shape preferably the shape of the recess 23. The material of Head 22 flows to form a radially inwardly directed rib-like projection 28 in the recess 23rd one. The head 22 is thus in particular in the region of the recess 23 flat and gapless on the annular surface 24 at. Furthermore the head 22 can also be radial in its remaining area be compressed to the inside, so that its through hole 25th completely and preferably with a certain bias the shank 21 abuts. The head 22 thus has an upper, for the introduction of force serving planar surface 29, a lower, also serving for force application plane surface 31 and a cylindrical surface 26 on which the lower, the Working part 15 of the shaft 21 facing plane surface 31st borders. The recess 27, however, preferably adjacent to the Planar surface 29. Further preferably, the head 22 is arranged that the plane surface 29 substantially with an upper Edge 32 is aligned, in which the cylindrical shaft 21 in the curved annular surface 24 passes. On the other hand is located the other edge 33 at which the annular surface 24 ends, preferably approximately at mid-height of the head 22.

The presented configuration has the advantage that the Head 22 on the shaft 21 in an axially desired and selected Position can be attached. It plays the Precision of the position of the recess 23 does not matter. The position of the head 22 becomes at the moment of crimping the head 22 set. Other manufacturing tolerances play thereby no or only a very minor role. It can be thus in a simple way punches 8 in high quality produce. It can also be in the simplest way very different Create embodiments by, for example differently shaped heads 22 with shafts 21 a and of the same type. It can be different axial head lengths or head diameters or head materials be applied. In addition, the heads 22 in different Axial positions in which the recess 23rd is within the through hole 25, to be attached. Furthermore, it is possible, the recesses 23 at different To mount shaft positions. This is especially true if the recesses 23 in a machining process, for example by grinding become.

The stamping punch 8 described so far works in the Punching tool 1 as follows:

As illustrated in FIG. 2, the upper tool 3 becomes moved back and forth in the direction of arrow 12. The head 22 is between the drive element 18 and the return element 19 held. Both grip on the flat surfaces 29, 31 of the Head 22 on. The power transmission between the head 22 and the shaft 21 takes place by positive engagement between the Projection 28 and the recess 23 (Figure 4). The power transmission is flat and uses the entire ring surface 24. It Therefore, neither comes to local voltage peaks, nor Shear effects. Even with fast work, the heads dissolve 22 of the stamps 8 not. This is an essential asset deriving from the fact that the projection 28 and the Recess 23 are the same shape or, strictly speaking, to each other have completely complementary shapes.

Die Ausnehmung 23 erstreckt sich nicht um den gesamten Umfang des Schafts 21 sondern lediglich über einen Teil desselben. Sie kann als gerundete, beispielsweise einer zylindrischen Mantelfläche folgende Kerbe vorgestellt werden. Optional kann an der gegenüber liegenden Seite und auf gleicher Höhe oder, wie dargestellt, axial versetzt eine weitere Ausnehmung 35 vorgesehen sein, die eine gleiche oder eine abgewandelte Form aufweist. Entsprechend weist der Kopf 22 nach Verformung des Rohlings 22' eine erste obere Vertiefung 27 im Bereich der oberen Ausnehmung 23 und eine Vertiefung 36 im Bereich der unteren Ausnehmung 35 auf. Die Vertiefungen 27, 36 sind durch radiale Kompression und Verformung des Rohlings 22' entstanden und bilden Dellen oder Einbuchtungen in der Mantelfläche 26.

For the punch 8 according to FIGS. 5 and 6, the above statements apply correspondingly, with the following exceptions:

The recess 23 does not extend around the entire circumference of the shaft 21 but only over a part thereof. It can be presented as a rounded, for example, a cylindrical lateral surface notch following. Optionally, on the opposite side and at the same height or, as shown, axially offset, a further recess 35 may be provided which has a same or a modified shape. Accordingly, after deformation of the blank 22 ', the head 22 has a first upper recess 27 in the region of the upper recess 23 and a recess 36 in the region of the lower recess 35. The recesses 27, 36 are formed by radial compression and deformation of the blank 22 'and form dents or indentations in the lateral surface 26.

As Figures 7 and 8 illustrate, the head 22 also extend upward beyond the recess 23, so that the upper plane 29 an axial distance to the edge 32 has. Preferably, however, remains between the lower plane 31 of the head 22 and the lower Edge 33 of the shaft 21 an axial distance, at least is about as large as the axial length of the recess 23rd and which is much larger than the diameter of the shaft 21. As a result, the head 22 is tilt-proof on the shaft 21st held.

Figures 9 and 10 illustrate a modified Embodiment of the punch 8, wherein the head 22 in addition for positive locking cohesively on the Shank 21 is secured. To make the connection is in the recess 23, a suitable connecting means, for example by pressure or heat or intimate metal contact curing adhesive 37 is arranged. This one will when donning the blank 22 'not stripped and thus remains as a depot in the recess 23. In the following plastic deformation of the blank 22 'and the training the projection 28, which penetrates into the recess 23, the adhesive 37 is largely displaced, where he on both sides of the recess 23 in the between the head 22 and the shaft 21 formed gap penetrates and this under the formation of an adhesive joint 38 fills. The adhesive 27 can subsequently cure over time. In addition, can it is cured by heat. It can too Adhesives are used which cure once the glue line a minimum size falls below, as happens with some instant adhesives the case is.

The punch of the invention has a positive fit held head 22 on. The head 22 is at the Shank 21 of the punch 8 held by by plastic Deformation, for example by radial pressure application, material displaced radially inward, so that a Projection 28 forms the area on the wall of a Recess 23 is present. It is a safer and more permanent Force transfer ensured.

LIST OF REFERENCE NUMBERS

1

punching tool

2

lower tool

3

upper tool

4, 5

guides

6

recording device

7

punch holes

8th

stamp

9

Down plate

11

gap

12

arrow

13, 14

guide bush

15

working part

16

Rifle

17

holder

18

driving element

19

return element

21

shaft

22

head

22 '

blank

23

recess

24

ring surface

25

Through Hole

26

lateral surface

27

deepening

28

head Start

29, 31

plane surfaces

32, 33

edge

35

recess

36

deepening

37

adhesive

38

bonded joint

Claims (21)

Punch (8) for a green-sheet punching device (1),
with a shank (21) provided at one end with at least one recess (23),
with an annular head (22), which has a projection (28) which engages in the recess (23) and thereby locks the head (22) in a form-fitting manner on the shaft (21), by plastic deformation. Punch according to claim 1, characterized in that associated with the projection (28) is a recess (27) formed during the production of the projection (28). Punch according to claim 1, characterized in that the recess (23) is an annular bead. Punch according to Claim 1, characterized in that a plurality of recesses (27, 35) arranged in an annular region thereof are formed on the shaft (21). Punch according to claim 1, characterized in that the recess (23) has a waisted shape. Punch according to claim 1, characterized in that the recess (23) is bounded by an annular concavely curved annular surface (24). Punch according to claim 6, characterized in that the annular surface (24) is formed without edges and without offset. Punch according to one of claims 2 to 7, characterized in that the recess (27) has a recess (23) adapted shape. Punch according to one of claims 2 to 7, characterized in that the recess (27) is formed in a non-cutting shaping operation. Punch according to one of claims 2 to 7, characterized in that the recess (23) is arranged completely within the head (22). Punch according to one of claims 2 to 7, characterized in that the recess (27) on the outer peripheral surface (26) of the head (22) is arranged. Punch according to claim 1, characterized in that the head (22) is substantially cylindrical. Punch according to claim 1, characterized in that the head (22) has at least one substantially flat end face (29, 31). Punch according to claim 13, characterized in that the end face (29) adjoins the recess (23). Punch according to claim 1, characterized in that the head (22) has a through-bore (25) which has been narrowed during assembly of the head (22) on the shank (21) by plastic deformation of the head (22) the shank (21) is held free of play in the passage bore (25) over the entire axial length of the head (22). Punch according to claim 1, characterized in that the head (22) has a through-bore (25) which has been narrowed during assembly of the head (22) on the shank (21) by plastic deformation of the head (22) the shaft (21) is held without gaps in the through hole (25) over the entire axial length of the head (22). Punch according to claim 1, characterized in that the head (22) consists of a metal. Punch according to claim 1, characterized in that the plastically deformed head (22) on the shaft (21) is positively secured and additionally cohesively. Punch according to claim 18, characterized in that for the material-locking securing of the head (22) an adhesive deposit (37) is used, which is arranged in the recess (23) of the shaft (21) before the plastic deformation of the head (22). Punch according to claim 18, characterized in that for the cohesive securing of the head (22) adhesive (37) is used, which is arranged after the plastic deformation of the head (22) in the recess (23) of the shaft (21). Punching device (1) with a punch (8) after a of the preceding claims.

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