SE514093C2 - Method of punching of packaging material and punching form and use thereof - Google Patents

Abstract

A punch form (1) for die-cutting of packaging material (7), comprising cutting knives and/or scoring rules, wherein the punch form at least partly is provided with sheet material provided in such a way that a crack-reducing effect is achieved in the packaging material, at least in connection to the cutting knives and/or scoring rules, wherein the sheet material is air permeable to during die-cutting evacuate air between the packaging material and the parts of the punch form which are provided with sheet material; a method for die-cutting packaging material by means of a punch form as above, in which air between the packaging material and the punch form provided with sheet material is evacuated; and the use of a punch form as above.

Description

J 514 093 'j 2 and / or punching rulers and a punching stop, the punching taking place at high speed.

The punching devices, ie punching knives, punch rulers, etc., are usually mounted on a flat or cylindrical bed, so-called flat punch shape and rotary punch shape, respectively. For each package to be produced, a specially designed punch mold is required, which is mounted in the current punching machine at the time of production.

The punching stops can be in the form of a flat plate or a rotating cylinder.

In the punch pinch, the punching knives completely cut through the packaging material, while the punching rulers and other punching devices only partially cut through or only deform the packaging material. Usually, crease or fold lines are provided, which weaken the flexural stiffness of the packaging material.

The punched packaging material is pushed out of the punching mold by means of resilient elements, usually so-called ejector rubbers. Such ejector rubbers are generally in direct contact with the packaging material.

After the ejection from the punch mold, the punched packaging material is fed on and the packaging blanks are cleaned of excess material, so-called punch waste, in connection with leaving the punch mold and the punch pinch in question or immediately after.

There is often a certain buckling of the packaging material when it is applied to the punch mold, during the punching pressure load, during feeding through the punch, during ejection and during cleaning, which can lead to packaging blanks with incorrect dimensions or incorrect cutting positions or damage to the packaging blanks. The problems increase with increased production speed.

Another problem is damage to the surface of the packaging material caused by the ejector rubbers, especially when punching pressure-sensitive packaging materials and at high production speeds.

.M A | These problems can be alleviated by applying a crack-absorbing sheet material between the punch mold and the packaging material, as shown in EP 454 753 B1, the contents of which are hereby incorporated into this specification.

The crack-absorbing sheet material may be applied to parts of or over the entire punch shape. Even with this solution, problems can arise with damaged packaging blanks, with incorrect dimensions or incorrect cutting positions in relation to graphic printing or the like. These problems increase with increasing production rate.

SUMMARY OF THE INVENTION The object of the present invention is to improve the known defects in the punched packaging blanks in a simple and inexpensive punching technique in order to minimize undesired ways and at the same time allow increased production speed.

In accordance with the invention, this is achieved by a method and a punching form, according to the introductory paragraph, which have the features of the appended claims.

The invention means that the crack-absorbing sheet material is provided with openings or holes, especially perforations. Alternatively, a porous, air-permeable sheet material can be used.

The invention is thus based on the realization that air permeability of the sheet material solves the problems of punching. The invention has been found to give the effect that stable contact occurs quickly and that the packaging material is quickly smoothed out when the packaging material is applied to the punch mold. When using the invention, the air is effectively evacuated between the packaging material and the punch mold when the packaging material is applied to the punch mold. 5 15 20 25 30 35 _ 514 093 '4 The same applies when the punching mold and the abutment are quickly compressed or when the packaging material enters the punching pinch.

It has been found that the punching processes work well even at high punching speeds, although increased punching speed increases the requirement for air permeability of the sheet material.

To enhance the above effect, negative pressure can be applied either to spaces in the space between the bottom of the punch and the apertured or air-permeable sheet material, which spaces are preferably delimited by ejector elements, or directly to the openings.

The punch shape is preferably divided into a number of separate spaces. Negative pressure can thus be selectively, both spatially and temporally, applied to different openings and spaces, which, for example, enables the punched packaging blanks to be held against the punch shape while the punch spill is removed. Preferably, in a corresponding manner, overpressure can also be selectively applied to different openings or spaces, which, for example, facilitates the removal of the punch waste when the packaging blanks are held by means of negative pressure. Of course, the overpressure or negative pressure can be applied in reverse, for example so that the punch waste is retained while the packaging is passed on. Of course, only some of the spaces can be provided with openings.

The application of negative pressure also has the advantage that no sliding of the packaging material takes place relative to the punching form during the punching process.

Negative pressure can be applied before the punch mold and the packaging material are introduced into the punch nip to be selectively disconnected after the punch nip and then completely disconnected after cleaning of the punch spill. Those skilled in the art will appreciate that negative pressure can also be applied to selective parts of the air permeable sheet material. Preferably, the sheet material is mounted at substantially the same level over the various parts of the punch, for example on equally high ejector rubbers, so that the packaging material is prevented from buckling. The sheet material should have such a large bending resistance that the packaging material is not dented into the punching mold during the entire punching process.

The sheet material can preferably cover all of the punch shape of the punch, including the areas for punch spillage and a bit outside the outer punch knives. As a result, the contact between the punch mold and the packaging material in different parts of the punch mold will be synchronized and become uniform, which reduces the occurrence of disturbing acceleration or deceleration forces in the packaging material during the punching process.

The sheet material according to the present invention ensures that the ejection of the packaging material takes place synchronously in different parts of the punch mold and effectively prevents parts of the packaging material from getting stuck in the punch mold and interfering with the continued production.

It has been found suitable with an air permeability of at least about 1.5 m3 per m2 and second calculated over the surface of the punch mold, preferably at least 2 m3 per m2 and second and preferably at least 3 m3 per m2 and second at normal production speeds, typically 2-3 m / s. At higher production speeds, the requirement for air permeability of the sheet material increases.

It has been found that the invention greatly prevents problems associated with the packaging material sliding relative to the punch shape. The present invention thus provides an opportunity for increased production speed as well as an improved punching result, even for very light and sloppy packaging materials.

Further advantages are that the sheet material, especially when mounted on a level above the edges of the punching knives, protects the user from being damaged on said punching knives, and especially when the entire punching form is covered by sheet material, the punching forms become easier to stack and handle and easier to clean from dust and paper materials.

One aspect of the invention is that it can be seen, inter alia, as a further development of the invention in EP 454 753 B1, the contents of which have previously been referred to for incorporation in this application.

Brief Description of the Drawings Preferred embodiments of the invention will now be illustrated by way of example and with reference to the accompanying drawings, in which: Figure 1 shows the invention in a process with a flat punch shape and a flat punch resistance.

Figure 2 shows the invention in a process with a flat punch shape and a rotating cylinder as punch resistance.

Figure 3 shows the invention in a process with a rotary punch shape and a rotating cylinder as punch resistance.

Figure 4 shows diagrammatically in detail a punch shape provided with sheet material having holes.

Figure 5 shows schematically in detail a punch shape provided with a porous, air-permeable sheet material.

Figures 6a, 6b and 6c show plan punch shapes from above with examples of placement of openings, slots and perforations in the sheet material.

Figure 7 shows two packages in that punched packaging material.

Figure 8 shows the packages in Figure 7 after cleaning of punch waste.

Figure 9 shows from the side suction of the packages in figure 7 while the punch waste is cleaned away.

Figure 10 shows from the side suction of the punch waste while the packages in figure 7 are removed. Description of Preferred Embodiments Referring to Figure 1, an embodiment of the present invention will be described in a punching process in which a flat punch 1, a flat punch 2, and means for abutting the punch 1 against the punch 2 planar punch 1 is provided with a sheet material 3 (not shown) is used. which is arranged, for example glued, on resilient elements 4; so-called ejector rubbers 4. The sheet material 3 is provided with openings 5, for example round with a typical diameter of about 4 mm or slit-shaped with a typical width of about 3 mm. The length of the slit-shaped openings varies depending on the shape of the packaging blank. The openings 5 are preferably placed in the vicinity of the ejector rubbers 4 so as not to weaken the stiffness of the sheet material 3 too much but also not too close to them so that 6b and 6c illustrate three different ways of placing openings in not disturbing their function. In Figures 6a, the sheet material. Figure 6a shows holes, figure Gb shows slits and figure 6c shows perforations.

Along punch knives 6 and punch rulers 6 there are slots 16 arranged in the sheet material. These slots cannot be compared with the air evacuating openings 5 in the sheet material because the sheet material slides close to the punch 6 and because the ejector rubbers 4 are arranged close to the punch, i.e. there is virtually no space where air could be evacuated.

The sheet material 3 is preferably mounted at a level above the edges of the punching knives 6 so that the sheet material 3 comes into contact with the packaging material 7 to be punched before the punching means 6 'in the punching pinch 8.

The packaging material 7 is fed onto the punch holder 2, after which the punch mold 1 is pushed against the punch holder 2 and the packaging material 7 so that a packaging blank 9 is punched out. When the punching mold 1 is pushed against the punching support 2, there is usually a risk of an air cushion forming between the packaging material 7 and the sheet material-provided parts of the punching mold 1. The problems increase with increasing speed. The impact velocity is of the order of 10 times greater than the feed velocity of the packaging material 7 into the punch nip 8.

Since the sheet material 3 according to the invention is air-permeable, the air between the packaging material 7 and the sheet material 3 will be evacuated, as a result of which the previously reported problems are eliminated.

After punching, the packaging material 7 is fed out of the punch nip 8 and the punched packaging blank 9 is cleaned from punch waste 10 in a conventional manner.

The sheet material 3 may, for example, be of plastic, preferably of polypropylene plastic, and with a typical thickness of 1-1% mm.

The person skilled in the art realizes that instead of distinct openings, a perforated, ie provided with a larger number of smaller holes, or in itself porous, air-permeable sheet material can be used. This of course applies to all embodiments shown.

An example of a porous, air-permeable sheet material is a plastic fabric, preferably polypropylene plastic. The fabric can preferably be mounted in double layers.

Figure 2 shows another embodiment of the present invention. The punching mold 1 is flat and movable in this punching process and the abutment 2 is a rotating cylinder.

The punching pin 8 arises where the cylinder 2 is pressed against the punching mold 1 and is thus moved along the punching mold 1 during the punching.

The packaging material 7 is applied to the sheet material-provided punch 1, wherein air present between the packaging material 7 and the sheet material 3 is evacuated through said air-evacuating openings 5, perforations or porous, air-permeable sheet materials 3. The punch 1 is then introduced into and through the punch nip 8, after which the punched packaging blanks 9 are cleaned from punch waste 10 in a conventional manner.

In order to further reduce sliding movements of the packaging material 7 when applying the packaging material 7, the transport into the punch nip 8 and into the punch nip 8 itself, negative pressure can be applied to the apertured sheet material 3 from inside the punch 1 by means of negative pressure generating means (not shown in Fig. 2).

This is further illustrated in Figures 4 and 5, where Figure 4 shows an embodiment with openings 5 in the sheet material 3 and Figure 5 shows an embodiment with a perforated or porous, in itself air-permeable sheet material 3. the sheet material covering the punch is perforated or Figure 5 shows a variant in which the whole is porous. Of course, only selected parts of the sheet material can be perforated, porous or apertured.

The bottom 12 of the punch 1, the sheet material 3 and, for example, the ejector rubbers 4 form spaces 13.

Air ducts, preferably conduits 11 in the form of hoses mounted in grooves or ducts, are arranged in the bottom 12 of the punch 1 between the negative pressure generating member 15 and the spaces 13 to be pressurized.

The punching mold 1 is preferably provided with a number of separate spaces 13. When the spaces 13 in Figure 4 are subjected to a negative pressure, a suction will arise in the openings 5 in the sheet material 3, which will suck the packaging material 7 against the sheet material 3.

The same applies in Figure 5, where the negative pressure means that a suction will arise through the perforated or porous, air-permeable sheet material 3, which will suck the packaging material 7 against the sheet material 3. The openings 5 in the sheet material 3, the negative pressure can also be imparted separately by, for example, pulling a hose 11 all the way to the respective opening 5, see Fig. 4. In this way, different parts of the punching mold 1 can be imparted selectively and at different times.

Returning to the punching process illustrated in Figure 2, the suction function is used as follows.

When the packaging material 7 is applied to the punch 1, a negative pressure is also applied to the sheet material 3 so that the packaging material 7 is held against the punch 1. This negative pressure is maintained during transport and into the punch 8. Then the openings 5 or spaces 13 corresponding to the punch 10 are successively disconnected. , whereby the punching waste 10 is cleaned from the punched-out packaging blanks 9 while the packaging blanks 9 are still held by means of the negative pressure. 9 and 10, shows two packaging blanks 9 in a punched This can be seen in Figures 7, 8, where Fig. 7 packaging material 7. The dashed area shows the punch waste 10. The packaging blanks 9 have received crease lines 14. Figure 8 shows the two packaging blanks cleaned from punch spills 10 9.

Figure 9 illustrates how the packaging blanks 9 are sucked against the sheet material 3 while the punch waste 10 is cleaned away. Of course, the reverse may be the case, see figure 10, where instead the punching waste 10 the sheet material 3 and the packaging blanks. After the cleaning operation is disconnected, suction fixed to 9 is removed. the negative pressure completely and the packaging blanks 9 are fed on, whereby the punching mold 1 returns to the initial position.

If the punching device shown in Figure 1 is designed so that the punching mold 1 and the punching bracket 2 have exchanged places, i.e. the packaging material 7 is fed onto the punching mold 1 and the punching bracket 2 abuts against the punching mold 1, of course a suction function as above is arranged in the punch mold 1.

Figure 3 shows a further embodiment of the present invention where the apertured sheet material 3 is mounted on a rotary punch 1, i.e. a cylindrical punch 1. The punch 2 is also cylindrical and both punch 1 and punch 2 rotate but in different directions.

The packaging material 7 is fed into the punch 8 between the punch 1 and the punch holder 2 and the air between the packaging material 7 and the punch 2 is evacuated through the openings 5 in the air-permeable sheet material 3. After the punch 8 the punch 10 is cleaned away in a conventional manner. This embodiment can also be provided with a suction function as described above. In this case, the openings 5 and the spaces 13, respectively, in the punching mold 1 are connected to a negative pressure-creating member via transfer means (not shown) which are arranged at one shaft attachment of the punching mold 1. In addition, there are control means (not shown) which control the negative pressure so that negative pressure with the rotation of the punch 1 is applied before the punch 8 to be either selectively released after the punch 8 and totally after the cleaning or completely disconnected after the punch 8.

Of course, the rotary punch 1 can be used together with a flat punch 1 as well.

Claims (19)

t 514 093 i t 12 BAIENIKRAH Punching mold for punching packaging material, comprising punching knives (6) and / or punching rulers (6), the punching mold (1) being at least partially provided with sheet material (3) so arranged in the punching mold (1) that crack damping of the packaging material (7) is obtained at least in connection with the punching knives and / or the punching rulers (6), the sheet material (3) being air-permeable in order to evacuate air between the packaging material (7) and the sheet material-provided parts of the punching mold (1). p Punching form for punching packaging material according to claim 1, wherein the sheet material (3) is provided with air-evacuating openings (5). Punching form for punching packaging material according to claim 1 or 2, wherein the sheet material is perforated to achieve the desired air permeability. A punch for punching packaging material according to claim 1, 2 or 3, wherein the sheet material is porous to achieve the desired air permeability. Punch form according to claim 1, 2, 3 or 4, wherein the air permeability is at least about 1.5 HP per m2 and second calculated over the surface of the punch form (1), preferably at least 2 n fi per m2 and second and preferably at least 3 n fi per n fl and second. Punch mold according to claim 1, 2, 3, 4 or 5, wherein the punch mold (1) is so arranged for applying a negative pressure from the side of the sheet material (3) which does not abut against the packaging material (7) which should be punched, through the air-permeable sheet material (3) so that the packaging material (7) to be punched is sucked against the sheet material (3) of the punch mold (1). A punch mold according to claim 6, wherein conduits (11) are directly attached to at least one opening (5) in the sheet material (3) of the punch mold for connection to a negative pressure generating member (15). Punching according to claim 6, wherein conduits (11) are connected to at least one delimited space (13) where there are openings (5) in said sheet material (3), for connection to a negative pressure-creating means (15) . Punch mold according to claim 6, 7 or 8, wherein the punch mold (1) is divided into more than one delimited space (13). A punch mold according to any one of the preceding claims, wherein the punch mold (1) is completely covered by said sheet material (3). Method for punching packaging material by means of a punching form, comprising punching knives (6) and / or punching rulers (6) and sheet material (3) arranged in the punching mold (1) such that crack damping of the packaging material (7) is obtained at least in connection with the punching knives and / or the punching rulers (6), where the packaging material (7) is inserted between said punching mold (1) and a punching bracket (2), the punching mold (1) and the punching support (2) being brought together so that the packaging material ( 7) punching, in which an air-permeable sheet material (3) is used, by means of which air is evacuated between the packaging material (7) and the punching mold (1) provided with at least partially sheet material. A method of punching packaging material according to claim 11, in which an apertured, porous or perforated sheet material (3) is used. A method of punching packaging material according to claim 11 or 12, in which air is actively evacuated by suction through the sheet material (3). A method for punching packaging material according to any one of claims 11-13, in which a negative pressure is applied in the punch mold (1) so that the packaging material (7) is sucked against the air-permeable sheet material (3) of the punch mold (1). _ A method for punching packaging material according to claim 14, in which negative pressure is selectively imparted and disconnected from the various armored wear parts of the punch mold (1). 16. .16. A method for punching packaging material according to claim 14 or 15, in which a negative pressure is applied before insertion into the area where the punching mold (1) and the punching counter (2) cooperate for punching and selectively disconnected according to said area. A method for punching packaging material according to claim 14, 15 or 16, in which negative pressure is switched off after the remaining punch waste (10) has been removed after the punching. A method for punching packaging material according to claim 13, 14, 15, 16 or 17, in which one or more packages (9) punched out of the packaging material (7) are sucked against the punch mold (1) and the negative pressure on the punch waste (10) is disengaged. while the punch waste (10) is cleared away. Use of a punch mold, for punching packaging material, comprising punch knives (6) and / or punch rulers (6) and an air-permeable sheet material (3) which at least partially covers the punch mold (1) and which is arranged in the punch mold (1) for ¿, 5 {¿¿contact with said packaging material (7) when punching packaging material (7) so that air between the packaging material (7) and the sheet material-provided parts of the punch mold (1) is evacuated through the air-permeable sheet material (3) during punching of the packaging material (7).