EP1839825A1 - Method and apparatus for producing perforated sheet material - Google Patents

Abstract

The method involves producing holes in a film or foil (2) by a needle-like tool (16) while crimping the edges of the resultant holes in the film or foil with clamping elements preferably a lower tool (6) and a tool guide plate (9). The film or foil is guided and clamped between two clamping elements. An independent claim is included for the device for perforation of films or foils.

Description

The invention relates to a method and a device with which perforated films can be produced.

Frequently films, such as plastic films, metal foils or plastic-metal composite films are provided with a number of holes, the holes are often to have only a small hole diameter. In principle, various processes are known for the production of perforated films.

The DE 299 08 254 U1 discloses the production of perforated films by means of two counter-rotating rollers, between which the film to be perforated is passed. The rollers are provided with cutting teeth which form short tears in the film passing between the rollers, which are more or less widened by the wedge shape of the teeth.

In this process, no material is removed from the film. There is a risk that the tears formed largely close again when the film has elastic properties.

Furthermore, from the DE 39 06 573 A1 a method for piercing very small holes in a film web or tubular film is known, in which the film web is guided over a piercing roller. In the piercing roller needle strips are provided, the needles, when the needle bars are moved by an eccentric radially outward, piercing the film web.

The JP 2001 001 007 A discloses a method for producing a perforated film by means of a profile roller and an elastic pad. The metal foil to be perforated is placed on the elastic base over which the profiled roller is rolled. As a result of the pressure exerted, portions of the elastic base penetrate into recesses of the roller and separate film sections from the film. This is a punching process.

Furthermore, thin sheets, for example, not too thin metal foils can be punched by punch, each punch then on the other side of the foil an insert is associated with a cutting opening, which forms a cutting gap with the punch.

This method reaches its limits with decreasing sheet metal or film thickness, because the cutting gaps must be narrower than the film thickness. With thin films, it is hardly possible to achieve sufficient free-standing quantities. For very small hole diameters of e.g. 100 microns is also difficult to ensure that all punches (for example, several hundred or several thousand) find in the associated holes of the insert.

On this basis, it is an object of the invention to provide a method by which perforated films can be produced in a simple and economical manner.

This object is achieved by the method according to claim 1:

In the method according to the invention, first holes are produced in the film, for example by the film being pierced at several points. Subsequently, the edges of the resulting holes of the film are pressed. This measure ensures that standing away from the edges of the hole short Folienzipfel or lobes do not close the resulting hole again. Rather, these lobes or flaps are deformed so that they, even if they relax elastically something, the resulting hole can not close.

This method is suitable both for metal foils and plastic films or composite films, such as metallized plastic films or metal foils with plastic coating, paper with metal coating, paper with plastic coating or coated films made of different materials. The film thickness can vary within wide limits. The

Method is particularly suitable for processing films with a thickness of a few tens of micrometers, for example 50 microns. It can holes are introduced into the film whose diameter is smaller or larger than the film diameter. For example, holes with a diameter of 100 μm can be inserted into an aluminum foil with a thickness of 50 μm. While the hole is first opened in the step of piercing the film, it is fixed in the step of pressing the edge of the hole concerned. The hole shape can be maintained or changed depending on the process. The hole shape can be largely determined or left to random process influences.

The generated holes may be substantially round or polygonal or irregularly shaped. The hole shape may be influenced by the cross-sectional shape of a needle-like tool for piercing the film and / or, if it has no circular cross-section, by the orientation of the cross section of the tool to the film transport direction. In addition, the shape of the hole can be influenced by the way the hole edges are pressed.

The holes are preferably made with needle-like tools having a tip and a conically flared portion. After the tip has penetrated through the preferably held resting film, the tool is axially moved further, whereby the resulting hole is widened. The material displaced thereby forms lobes or lobes that stand away from the film. When pressing these tabs or lobes are pressed against the back of the film or compressed into it. The resulting hole edges are relatively smooth. They essentially exist from drawn into the hole, former surface areas of the film. Also, the film back is largely smooth by pressing.

Another object of the invention is to provide a device for producing perforated films. A corresponding device has a means for piercing the film and a means for preferably stationary or, if necessary, moving storage of the film during the piercing operation. Furthermore, a means for pressing the edges of the holes produced is provided. The means for pressing the edges of the holes produced allows a fixation of the holes produced in the stitch process, so that they can not close unintentionally. They are fixed in their shape and in diameter.

The means for piercing the film is preferably in at least one tool having an elongated working part with a tip, starting from which increases the cross section of the working part. In this sense, the working part is formed at least partially or conically as a whole. The diameter increase of the working part away from the tip may be linear, progressive or degressive or degressive-progressive degressive (s-shaped) or otherwise formed. The tip of the working part may be a point point or a cutting edge. In the case of a point tip, the tip is formed by a sphere portion or similarly shaped surface area of very small radius. In the case of the formation of the tip as a cutting edge, the working part ends in a straight or curved edge, which creates a small cut on the film during insertion, which is widened by the working part. The tool can be used for punching a linear axial back and forth to carry out walking movement. It is also possible to attach the tool or several tools to a rotating machine element, for example a roller, in order to perforate a passing film. A support means is then not necessary for the film. As support means can serve as an air cushion, for example.

Due to the formation of the tip as a cutting edge and the alignment of the cutting edges on the material transport direction of the film, for example, along this, the position of the resulting by the insertion of the tools on the film tabs or lobes can be set as it favorable for the subsequent compression process is to push the rag or tail on the back of the film, but not in the tap hole.

The working part of the tool can have a circular cross section, a knife cross section, a polygonal cross section or another cross section. Knife and polygon cross-section allow the targeted determination of the positions of the first edge of the edge of the hole or flap. A knife cross-section is, for example, a slender triangular cross-section (two corners and edges bent away from each other) or a triangular or polygonal cross-section with at least one very acute angle (for example a narrow rhombus).

The working part may have a section with a constant cross section in a section. This is advantageous if the size of the stitch hole should be independent of the stroke of the tool. If the piercing process is limited to the conical section of the working part, the hole size can be regulated with the stroke distance.

The film is placed on the means for storing the film when piercing, for example, a support table. This is preferably provided with openings into which the needles or other tools can enter. These openings preferably have a diameter which is significantly greater than the diameter of the working part associated with the relevant opening. The diameter is preferably so large that no cutting gap is created. The annular space between the working part and the wall of the opening has a width which is greater than the film thickness to prevent pinching the pierced in the opening hole edges.

The means for pressing the edges of the holes preferably has two elements with pressure surfaces between which the film is pressed. The elements may be arranged to be stationary, linearly movable or rotatable. The elements can also be designed either rigid or flexible. They may be formed, for example, by a stiff or elastic support, a rigid or elastic stamp associated with it, or rigid or flexible rollers.

In order to move the film continuously or in accordance with the cycle of the piercing movement of the needle-like tools in a stepwise manner, a transport device is preferably provided. The transport device can at the same time form the means for pressing the edges of the holes produced in the unit. For example, two rollers, which progressively convey the film and between which the film passes, can simultaneously cause the edges of the holes to be pressed. Also, jaws that squeeze the film can periodically clamp and progressively promote the film.

Figur 1

eine Vorrichtung zum Perforieren einer Folie in schematisierter, teilweise geschnittener Darstellung,

Figur 2

einen Ausschnitt aus der Vorrichtung nach Figur 1 in schematisierter, vergrößerter Darstellung, vor der Erzeugung eines Lochs,

Figur 3 und 4

die Vorrichtung nach Figur 2 während der Erzeugung eines Lochs in unterschiedlichen Stadien und in vertikal geschnittener, schematisierter Darstellung,

Figur 5

die Vorrichtung nach Figur 2 bis 4 nach Erzeugung des Lochs,

Figur 6

der zu der Vorrichtung nach Figur 1 gehörige, zum Verpressen der Lochränder gehörige Teil vor dem Verpressen der Lochränder,

Figur 7

der Vorrichtungsteil nach Figur 6 während des Verpressens der Lochränder,

Figur 8

die Folie mit hergestellter Perforierung nach dem Verpressen in vertikal geschnittener Darstellung des hergestellten Lochs,

Figur 9

einen Abschnitt des Arbeitsteils des Werkzeugs zur Herstellung eines Lochs in Seitenansicht,

Figur 10 bis 14

verschiedene Konfigurationen der Spitze und des Querschnitts des Arbeitsteils gemäß Figur 9 in Blickrichtung auf die Spitze.

Details of advantageous embodiments will become apparent from the claims, the drawings or the description. In the drawings, embodiments of the invention are illustrated. Show it:

FIG. 1

a device for perforating a film in a schematic, partially sectioned illustration,

FIG. 2

1 shows a detail of the device according to FIG. 1 in a schematized, enlarged representation, before the creation of a hole,

FIGS. 3 and 4

FIG. 2 shows the device according to FIG. 2 during the production of a hole in different stages and in a vertically sectioned, schematic illustration;

FIG. 5

the device according to FIGS. 2 to 4 after production of the hole,

FIG. 6

1 belonging to the device according to Figure 1, belonging to the pressing of the hole edges part before the pressing of the hole edges,

FIG. 7

the device part according to FIG. 6 during the pressing of the hole edges,

FIG. 8

the film with produced perforation after the pressing in vertically cut representation of the produced hole,

FIG. 9

a section of the working part of the tool for producing a hole in side view,

FIGS. 10 to 14

different configurations of the tip and the cross section of the working part according to Figure 9 in the direction of the tip.

FIG. 1 schematically illustrates a device 1 which serves for perforating a film 2, which is guided through the device 1 as a film web. The film 2 is e.g. wound on a bale 3, which is supported by a take-off device 4 and, if necessary, selectively driven to rotate. The take-off device 4 can serve as a transport device for the stepwise movement of the film 2. Alternatively, not shown grippers or rollers may be provided which promote the film 2 gradually.

To the device 1 includes a means 5 for piercing the film 2. To the means 5 in the present embodiment includes a support means in the form of a lower tool 6. This is designed as a perforated plate over the preferably flat top slides the film 2. The upper side of the perforated plate forms a support surface 7 for the film 2.

To the means 5 further includes an upper tool 8 with a tool guide plate 9 preferably with a flat bottom. The tool guide plate 9 forms a gap with the support surface 7. In the tool guide plate 9 openings 10 are formed, which are in the lower tool 6 formed openings 11 opposite. The diameters of the openings 10, 11 may be the same or different from each other.

The upper tool 8 further comprises a head support plate 12 in which heads 13 are held by needle-like tools 14 for piercing the film. The tools 14 have a cylindrical shaft 15, for example, which protrudes into the openings 10 and is guided in a sliding manner. From the shaft 15, a working part 16 extends away, whose Preferably, the diameter is substantially smaller than the diameter of the opening 11. The working part 16 is preferably a straight portion which extends longitudinally to the shaft 15 and ends at a tip 18 via a conical portion 17 (Figure 2).

The head support plate 12 and the tool guide plate 9 are, as indicated in Figure 1, for example, mounted movably with respect to each other, the tool holder plate 9 is resiliently biased against a stop of the head support plate 12 away. The head support plate 12 is connected to a not further illustrated drive which is adapted to give it a reciprocating motion, as indicated in Figure 1 by an arrow. The stroke of the movement is so great that, on the one hand, the tool guide plate 9 can be lifted off the foil and, on the other hand, the working parts 16 of the tools 14 can be stung through the foil 2.

To the device 1 further includes a means 19 for pressing the film 2 for fixing holes produced. In the exemplary embodiment according to FIG. 1, this means 19 is formed by a fixed element 20 and a movably arranged element 21, which preferably have in each case flat pressure surfaces 22, 23 on the sides facing each other. While the element 20 is preferably arranged or is stationary in addition to the lower tool 6, which is likewise preferably stationary, the element 21, as shown in FIG. 1 by an arrow, is movable toward and away from the element 20. It may be rigid or yielding, for example, be arranged resiliently and / or be connected to the head plate 12 or with its own drive. Alternatively, both elements 20, 21 can not only to each other and away from each other but additionally in the direction of the film 2 are oscillated back and forth to promote the film 2 gradually.

The device 1 is used, for example, for perforating plastic or metal foils, for example aluminum foils or for perforating composite foils, which consist of plastic as well as of metal or else of other materials. Preferably, it serves to perforate films whose material is plastically deformable. The top plate 2 holds corresponding tools 14 in several rows, which preferably extend over the entire width of the film 2 or at least over the width of the area to be perforated. The tools 14 of the individual rows (for example, ten rows) may be offset from each other or arranged in a different pattern.

With the device 1 according to FIG. 1, the film 2 is perforated as follows:

As illustrated in FIGS. 1 to 6, the film 2 is inserted in the gap between the upper tool 8 and the lower tool 6 and between the elements 20, 21. The end of the film 2 is taken from the take-off device 4. The film 2 rests on the support surface 7, which thus forms a means 24 for the storage of the film 2 during the subsequent piercing operation.

To carry out the piercing operation or piercing step, the head plate 12 is moved in the direction of the lower tool 6 until the tool guide plate 9 clamps the film 2 against the bearing surface 7. This condition is illustrated in FIG.

While the plate 9 rests on the film 2, the top plate 12 is moved further down, so that the tip 18, as shown in FIG. 3, pierces the film 2. A tap hole is formed, which is widened by the conical section 17 as the tool 14 is moved further down into the opening 11. Preferably, the tool 14 is moved so far that the cylindrical portion of the working part 16 enters the now formed in the film 2 hole 25. The film material forced out of the hole 25 hangs down as a tab or flap 26 into the opening 11 and forms an edge 27 of the hole 25 (FIG. 4).

In this state, the hole 25 is fully opened. The upper tool 8 is again moved away from the lower tool 6, whereby initially, as illustrated in Figure 5, the working part 16 and the tip 18 drive out of the hole 25 and the tool guide plate 9 lifts from the film 2. She takes the film 2 with something, so that it is also lifted from the support surface 7. If necessary, this process can be supported by introducing air (compressed air) into the opening 11 or in separate, the support surface 7 passing through blow openings.

As long as the film 2 is released between the support surface 7 and the tool guide plate 9, it is further moved by one step, which is for example as large as to be measured in the film transport direction, detected by the tool 5 film length (to be measured from left to right in FIG 1). The perforated parts of the film 2 thus reach between the pressure surfaces 22, 23 of the elements 20, 21. This is illustrated in Figure 6 on the basis of the newly opened hole 25. There are now the elements 20, 21 moved towards each other so that the pressure surfaces 22, 23 clamp the film 2 between each other. The flaps or Zipfel 26 are pressed. A variant of how this can be done, Figure 8 can be seen. The ears 26 are compressed and folded on the back of the film 2, which has been located on the support surface 7 when opening the hole 25. The tips 26 are at least so far plastically deformed that they do not move back into the cross section of the hole 25. But you can also be pressed flat on the back of the film. They can lie there loosely or even glued to the back or be cold-welded. It is possible to support the pressing process by further measures, for example by ultrasonication of at least one of the elements 20, 21, by heat or by material fixing agents, such as fixing or adhesive coatings, which can be applied around the holes 25 on the back of the film.

Figures 9 and 10 illustrate the tool 14 as it may be used to pierce the film in a first embodiment. The working part 16 is substantially cylindrical, wherein the portion 17 forms a circular cone, the tip 18 is rounded. FIG. 10 illustrates the working part 16 of the tool 14 with respect to its tip 18.

Alternatively, the tip 18 may be otherwise shaped, as illustrated in particular FIGS. 11-14. In the figures 11 and 12, the tip 18 has a cutting edge shape, wherein the cutting edge can be relatively short (Figure 11) or even so long that it almost corresponds to the diameter of the working part 16 (Figure 12). In the latter case, the section 17 has a knife cross section, starting from a End cutting edge gradually merges into the circular section of the working part 16.

The tip 18 can, as illustrated in FIG. 13, also be formed on a pyramid-shaped region of the portion 17. The cross section of the portion 17 is thus bounded at least partially polygonal. It is also possible, as illustrated in FIG. 14, to make both the section 17 and the remaining part of the working part 16 polygonal, for example triangular, quadrangular or polygonal. In this way, non-circular holes 25 can be generated.

The means for piercing the film, as shown, by a needle-like tool 14 or by any other suitable means for piercing the film 2, such as a sharp air or water jet, other fluids or pressure waves formed therein, flexible Elemente.oder the like be formed. The means for pressing the edges of the holes produced may be formed by rigid, flat or non-planar surfaces provided on corresponding elements, or by non-figurative means such as fluids or pressure waves formed in fluids.

A device for producing perforated films has a means 5 for piercing the film 2 and a means 19 for pressing the edges 27 of the holes 25 thus produced. By pressing the edges 27 or the ends 26 of film material, the holes 25 are fixed after opening. To produce the holes 25 no punching tools are required, which cut the perforation of the film 2. Rather, the desired hole 25 is initially generated punctually or in a section during the stitching process and expanded. During pressing, the material bent out of the plane of the film during expansion is fixed in such a way that it does not close the needle hole again.

LIST OF REFERENCE NUMBERS

1

device

2

foil

3

bale

4

off device

5

medium

6

lower tool

7

bearing surface

8th

upper tool

9

Tool guide plate

10, 11

openings

12

Head holding plate

13

heads

14

Tools

15

shaft

16

working part

17

section

18

top

19

medium

20, 21

element

22, 23

Imprint areas

24

medium

25

hole

26

tip

27

edge

Claims (19)

Process for producing perforated films (2),
in which in the film (2) first holes (25) are produced and
in which the edges (27) of the resulting holes (25) of the film (2) are pressed. A method according to claim 1, characterized in that the holes (25) are produced with needle-like tools (14). A method according to claim 1, characterized in that the film (2) for piercing between two clamping elements (6, 9) is guided and clamped between them. A method according to claim 1, characterized in that for generating the holes (25) first creates stitch holes and these are subsequently widened. A method according to claim 1, characterized in that when pressing on the edges (27) of the holes (25) existing material on the film (2) is folded and pressed against this. Device for perforating foils (2),
with a means (5) for creating holes in the film (2),
with a means (19) for pressing the edges (27) of the holes (25) produced. Apparatus according to claim 6, characterized in that the device comprises means (7) for supporting the film (2) during the piercing operation. Apparatus according to claim 6, characterized in that the means (5) for piercing the film (2) comprises a tool (14) having an elongate working part (16) with a tip (18), starting from which the cross-section of the working part ( 16). Apparatus according to claim 8, characterized in that the working part (16) has the shape of a needle. Apparatus according to claim 8, characterized in that the tip (18) is a point tip. Apparatus according to claim 8, characterized in that the tip (18) has the shape of a cutting edge. Apparatus according to claim 8, characterized in that the working part (16) has a circular cross-section. Apparatus according to claim 8, characterized in that the working part (16) has a knife cross-section. Apparatus according to claim 8, characterized in that the working part (16) has a polygonal cross-section. Apparatus according to claim 8, characterized in that the working part (16) has a section with a constant cross-section. Apparatus according to claim 8, characterized in that the means for supporting the film (2) has a support surface (7) which are provided with openings (11) which are associated with the tool (14) for generating the holes (25). Apparatus according to claim 8 and 16, characterized in that the openings (11) each have a diameter which is greater than the diameter of the opening (11) associated with the working part (16). Apparatus according to claim 6, characterized in that the means (19) for pressing the edges (27) of the holes (25) comprises a first element (20) with a bottom of the film (2) facing the pressure surface (22) and a second element (21) with a top side of the film (2) facing the pressure surface (23) and a drive means for the two elements (20, 21) controlled to each other and move away from each other. Apparatus according to claim 6, characterized in that the film (2) is associated with a transport device (4) in order to move the film (2) stepwise through the device (1).

Images