EP3756842B1 - Kiss-cut draw knife - Google Patents

Description

FIELD OF INVENTION

The present invention relates to a cutting machine blade which is designed and precisely intended for kiss-cutting or through-cutting of stickers.

BACKGROUND OF THE INVENTION

For such cutting of stickers, cutting machines are used which provide a kiss-cut cutting mode and a through-cut cutting mode and in whose cutting tool the cutting machine knife according to the invention is used.

With kiss-cutting, the top side, i.e. the sticker itself, is to be cut through so that it can be removed in the desired shape. The bottom side, i.e. the carrier layer to which the sticker adheres, remains intact or is only slightly grooved, scored or cut. To make it easier to remove, the carrier layer is usually provided with an anti-adhesion coating, whereby the sticker, which has a special adhesive layer, adheres removably to this anti-adhesion coating.

When cutting through, both sides - the sticker and the carrier layer - should be cut through, as it is desirable for the sticker as a whole (i.e. with the carrier layer) to already show its shape. To make it easier to remove the sticker, an additional tab can also be cut out, whereby a small kiss-cut is usually made at the transition between the tab and the sticker so that the tab is not part of the sticker.

To ensure a perfect cutting result, there are special requirements for the knives used in the cutting modes mentioned. Cutting machine knives are known from the state of the art, which have a pointed or have a blade tip that is parallel to the cutting direction. Such knives are not optimal for the cutting process and have a limited lifespan because their blade tips tend to break out early.

TASK OF THE INVENTION

It is therefore an object of the invention to provide an improved cutting machine knife of the generic type for kiss-cut cutting and through-cut cutting. The cutting machine knife according to the invention is significantly less susceptible to wear due to its design, thus enabling a more stable cutting process and offering a longer service life with constant cutting precision.

SUMMARY OF THE INVENTION

The invention relates to a cutting machine knife for use in a cutting tool of a cutting machine, designed and precisely intended for cutting a sticker in a kiss-cut cutting mode of the cutting machine, in particular in addition to cutting the sticker in a through-cut cutting mode of the cutting machine, wherein the sticker has a cover layer and an adhesive layer, wherein the sticker carrier has an adhesion-reducing layer and a carrier layer, wherein the adhesive layer detachably adheres to the adhesion-reducing layer, wherein in the context of the kiss-cut cutting mode the cutting machine knife is automatically guided by the cutting machine in a cutting direction along the sticker and in the process completely cuts through the sticker and not or only partially cuts through the sticker carrier, optionally wherein in the context of the through-cut cutting mode the cutting machine knife is automatically guided by the cutting machine in a cutting direction along the sticker and in the process completely cuts through the sticker and the sticker carrier, wherein the cutting machine knife has the following: a holding section for inserting the cutting machine knife into a knife holder of the cutting tool, a cutting edge facing the cutting direction rectangular longitudinal axis, a blade with a cutting edge and a back, the cutting edge, when viewed in a plane spanned by the cutting direction and the longitudinal axis, forming a first angle with the cutting direction which is less than 90°, and an intermediate zone located between the cutting edge and the back which, again viewed in said plane, forms a second angle with the cutting direction which is between 130° and 170°.

In one embodiment, the second angle is between 140° and 160°, in particular 150°.

In a further embodiment, the first angle is less than 70°, in particular between 20° and 65°, in particular 35°, 45° or 60°.

The blade between the cutting edge and the intermediate zone preferably has a tip which is pointed or rounded, in particular wherein the cutting edge and the intermediate zone enclose a third angle which results from a subtraction of the second angle from the first angle.

The blade can taper along the longitudinal axis and with respect to an axis that is perpendicular to the longitudinal axis and the cutting direction, towards the tip at least on one side, in particular on both sides, in particular taper in a linear or curved concave or convex manner.

In one embodiment, a normal distance of the tip to the longitudinal axis is less than 0.04 mm, in particular 0.02 mm, especially 0.01 mm.

The back can taper parallel to the cutting direction and with respect to an axis that is perpendicular to the longitudinal axis and the cutting direction, at least on one side, in particular on both sides, in particular in a linear or curved concave or convex manner.

According to the invention, the intermediate zone forms a wedge-shaped triangular surface which runs from the tip to the back.

The longitudinal axis is preferably an axis of symmetry of at least a part of the cutting machine knife, in particular a central shaft, and wherein the axis of symmetry runs through the back with a tolerance of -0.01 mm to +0.01 mm, in particular wherein the back runs parallel to the longitudinal axis.

The intermediate zone can have a length, in particular between tip and back, of less than 0.04 mm, in particular between 0.03 mm and 0.01 mm, in particular 0.02 mm.

At least one of: the cutting edge, the intermediate zone and the back, runs, in particular, again when viewed in the said plane, linearly or curved, concave or convex.

The cutting machine blade preferably has a length of between 10 mm and 30 mm, in particular a length of less than 20 mm.

In particular, the cutting edge has a depth along the longitudinal axis of between 0.5 mm and 3 mm, in particular a depth of between 1 mm and 2.6 mm.

In one embodiment, the holding section has a diameter of between 2 mm and 4 mm, in particular a diameter of 3 mm.

The invention further relates to a use of the cutting machine knife according to the description herein used in a cutting machine with cutting tool.

The invention also relates to a cutting machine with a cutting tool into which the cutting machine knife is inserted as described herein, wherein the cutting machine provides a kiss-cut cutting mode or a through-cut cutting mode, which are intended for cutting a sticker, wherein the sticker has a cover layer and an adhesive layer, wherein the sticker carrier has an adhesion-reducing layer and a carrier layer, wherein the adhesive layer is detachably adhered to the adhesion-reducing layer, wherein in the kiss-cut cutting mode the cutting machine knife is automatically guided by the cutting machine in a cutting direction along the sticker and The sticker is completely cut through and the sticker carrier is not or only partially cut through, whereby in the through-cut cutting mode the cutting machine knife is automatically guided through the cutting machine in a cutting direction along the sticker and in the process completely cuts through the sticker and the sticker carrier.

BRIEF DESCRIPTION OF THE DRAWINGS

• Figur 1 zeigt eine gattungsgemässe Schneidemaschine, für welche das erfindungsgemässe Schneidemaschinenmesser genau vorgesehen und ausgestaltet ist;
• Figur 2 zeigt eine Ausführungsform des erfindungsgemässen Schneidemaschinenmessers;
• Figur 3 zeigt die Spitze der Klinge des Schneidemaschinenmessers aus Figur 2 in einer Detailansicht, wobei der zu durchtrennende Aufkleber, der Aufkleberträger und die Schneiderichtung zu sehen sind;
• Figur 4 zeigt die Spitze der Klinge des Schneidemaschinenmessers aus Figur 2 in einer dreidimensionalen Detailansicht;
• Figur 5 zeigt den Schichtenaufbau des zu durchtrennenden Aufklebers aus Figur 3 in einer Detailansicht;
• Figuren 6 und 7 zeigen ein gattungsgemässes Schneidemaschinenmesser aus dem Stand der Technik;

Further advantages of the present invention will become apparent from the detailed description and drawings.

• Figure 1 shows a generic cutting machine for which the cutting machine knife according to the invention is precisely intended and designed;
• Figure 2 shows an embodiment of the cutting machine knife according to the invention;
• Figure 3 shows the tip of the blade of the cutting machine knife from Figure 2 in a detailed view, showing the sticker to be cut, the sticker carrier and the cutting direction;
• Figure 4 shows the tip of the blade of the cutting machine knife from Figure 2 in a three-dimensional detailed view;
• Figure 5 shows the layer structure of the sticker to be cut from Figure 3 in a detailed view;
• Figures 6 and 7 show a cutting machine knife of the type in question from the state of the art;

DETAILED DESCRIPTION OF THE DRAWINGS

Figure 1 shows a cutting machine 1 of this type, which can move a cutting tool in the X and Y directions over a machine table 4 by means of a portal. The control for this is usually carried out by a control unit 2, which can be located in the cutting machine or externally. The cutting machine knife 3 is designed to be inserted into the tool holder. Using specially adjustable forces (e.g. via a spring force or via a servomotor), the cutting machine knife 3 is pressed in a defined manner onto the object 5 to be cut. This pressing is used for so-called kiss-cut cutting, in which only an upper layer of the object 5 is completely severed and a carrier layer that carries this upper layer either remains intact or is at most minimally scratched or grooved by the knife 3.

If the defined force of the pressing is increased in a defined manner, or if a defined cutting depth is set, the cutting machine knife according to the invention can also be used to advantageously carry out a through-cut cutting, in which the object 5 is completely severed and the knife tip only lightly touches the machine table 4. The machine table 4 is usually permeable to air, because by sucking in air, the object 5 can be held on the table 4 by the force of a vacuum generated thereby. The surface material of the table 4 can be based on polyurethane, or consist of a nonwoven fabric.

The object 5 is preferably a sticker that adheres to its carrier material, or more generally: a material that carries one or more stickers. Such stickers are usually self-adhesive films or paper.

A pressure mode is used for cutting stickers (the pressure mentioned above). Which type of film is cut with which pressure depends on the material specifications and may need to be determined and defined using cutting tests. The cutting machine is designed to measure the pressure exerted by the tip on the material. When the defined pressure is reached, this can optionally be signaled by a green LED.

The optimum processing depth is achieved in kiss cutting when the knife cuts through the cover layer 100, the adhesive layer 101 and part of the sticker carrier 11. This means that the adhesion-reducing layer 111 is grooved, cut or severed, and the carrier layer 110 is cut or remains intact. The components are in Figure 5 This type of cut ensures that a sticker can be removed from the sticker carrier without the sticker carrier tearing. Common film materials reach thicknesses of up to 3 mm.

With through-cutting, the optimum processing depth is achieved when the knife cuts through all layers, i.e. the sticker 10 and the sticker carrier 11, without damaging the machine table 4.

The knife on the cutting tool can be surrounded by a (e.g. cylindrical) slider, which presses the object 5 to be cut onto the table 4 in the cutting area. This ensures once again (i.e. in addition to any vacuum suction function of the table 4, which securely fixes the object 5) that the cut is carried out cleanly. The use of the slider is particularly suitable for processing reflective foils.

A pressure mode can be designed such that the module (cutting tool) exerts a constant pressure, adjustable between 30 and 3500 grams, on the processing material 5.

In addition to the pressure mode, there is also a so-called position mode, which is not suitable for kiss cutting, but only for through-cutting, where a defined cutting depth is set (and no pressure), which ensures that the material is cut completely through and the table is not cut. The position mode is therefore an alternative to the pressure mode for through-cutting.

The cutting machine knife 3 according to the invention is precisely designed for the kiss-cut cutting mode and the through-cut cutting mode and ensures that precise and predictive cutting results are achieved by setting defined cutting pressures or defined cutting depths. An embodiment of the invention is shown in the Figures 2 and 3 The semi-cylindrical holding section 6 is used to clamp the cutting tool of the cutting machine 1 and ensures that the knife is precisely aligned. The holding section shown is not essential to the invention and other possible designs of a holding section are known to the person skilled in the art.

Cutting machine knives are usually made from a cylindrical raw material. In the middle area of the knife 3, this cylinder is essentially still in tact and in relation to this, a longitudinal axis L is defined for the cutting machine knife 3, which is an axis of symmetry for this middle section.

With the cutting edge 7, the cutting machine knife 3 naturally first comes into contact with the object to be cut, as the cutting direction S in Figure 3 The cutting direction S is a vector that points from the cutting edge in the direction of the cutting feed. In the example of Figure 1 the tool moves relative to the table, but embodiments are also conceivable in which the table moves relative to the tool. Usually, the cutting direction S is perpendicular to the longitudinal axis L. A depth T of the cutting edge 7 - viewed parallel to the longitudinal axis L - is preferably between 0.5 mm and 3 mm.

The blade of the knife 3 also has a back 8 which is located away from the cutting edge. According to the invention, there is an angled intermediate zone 9 between the cutting edge 7 and the back 8, which ensures a surprisingly high wear resistance of the knife in the cutting modes mentioned and thus a long-lasting and constant precision of the cutting results. In addition, the cutting machine knife according to the invention allows a lower piercing force and a lower cutting force (along the cutting direction) in both cutting modes compared to known knives.

The view of Figure 3 lies in a plane spanned by the longitudinal axis L and the cutting direction S. According to the invention, in this view the intermediate zone 9 has an angle W2 to the longitudinal axis L of between 40° and 80°. This means that an angle with the cutting direction S of 130° to 170° prevails. If this angle approaches the range of approximately 60° (relative to L) or 150° (relative to S) an optimum of the inventive effects is increasingly achieved. The longitudinal axis L runs in Figure 3 through the intermediate zone 9, but preferably it runs along the back 8, with a tolerance range around the back of -0.01 mm to +0.01 mm.

When we talk about the cutting edge, the back and the intermediate zone, we generally mean their edge. These edges are preferably straight, i.e. linear. However, in other embodiments they can also have a curved shape.

During kiss cutting, the tip 12 of the blade extends "just" into the sticker carrier 11 so that it is not damaged as much as possible, but the sticker 10 is completely severed. In this situation, peak loads arise which require special requirements for the design of the cutting machine knife. Similar peak loads arise during through cutting, where the tip of the knife touches the machine table.

The intermediate zone 9 has - viewed normal to the longitudinal axis L or parallel to the cutting direction S - between the tip 12 and the back 8 a length Z which is preferably less than 0.04 mm, in particular between 0.03 mm and 0.01 mm, in particular 0.02 mm.

Figure 4 shows the area A again in a three-dimensional (but not necessarily dimensionally accurate) view. Here you can see how the intermediate zone 9 forms a wedge-shaped triangular surface, which runs from the tip 12 to the back 8, ie a triangle is formed by the two corners on the back 8 and the tip 12. This surface can be completely flat, or in other embodiments concave or convex. The back also preferably has a flat surface, as in the Figure 4 can be seen. This surface can also take on other shapes in other embodiments - as with the above-mentioned triangular surface of the intermediate zone. The cutting edge 7 is of course sharpened and is therefore a sharp edge. The sharpening can also be linear or curved (concave or convex).

Figure 5 shows the layers of the object to be cut in detail in a side view. The sticker 10 has a cover layer 100 and an adhesive layer 101 firmly connected to the cover layer 100. Using this adhesive layer 101, the sticker 10 adheres to the adhesion-reducing layer 111 of the sticker carrier 11. The adhesion-reducing layer 111 is in turn firmly connected to the carrier layer 110. The material of the adhesion-reducing layer 111 is based on silicone or wax, for example. The cover layer 100 and the carrier layer 110 can consist of paper and/or plastic film.

The design of the knife 3 according to the invention specifically improves the process of cutting stickers and minimizes the wear that occurs on knives of the prior art and is briefly explained below.

Figure 6 shows the structure of a typical kiss-cut knife with cutting edge 14 and back 15. Figure 7 the in Figure 6 tip area labeled B. Between the cutting edge 14 and the back 15 there is a so-called flat spot 16, which also extends slightly into the carrier 11 during kiss-cutting and completely cuts through the sticker 10. The flat spot 16 is provided to prevent a "perfect" tip, ie a tip that tapers to a point, from breaking off.

The cutting process of such a knife 13 known from the state of the art is not optimal, however, because depending on the design of the flat spot 16, the area of the knife back 15 rests on the carrier layer. This causes higher cutting forces and vibrations during cutting, which impairs the cutting result. Furthermore, this effect greatly limits the service life. This is due to wear, which is shown by first breaks 17 in the area of the flat spot 16 and second breaks 18 in the area of the back 15. The results of kiss-cut cutting and through-cut cutting therefore no longer meet the requirements relatively early on and the knife must be replaced. In addition, the flat spot 16 causes higher piercing forces, which is relevant because the Cutting machine knives are typically lifted off and reinserted (at a different location or in a different orientation) frequently in a sticker cutting process.

The knife 3 according to the invention avoids all these signs of wear and tear and thus offers a significantly better cutting quality as well as an increased service life.

While the invention has been described in terms of its preferred embodiment(s), many other changes and variations may be made without departing from the scope of the present invention. Therefore, it is intended that the appended claims cover such changes and variations as come within the true scope of the invention.

Claims (14)

1. Cutting machine knife (3) for insertion into a cutting tool of a cutting machine (1), designed and precisely provided for cutting a sticker (10) in a kiss-cut cutting mode of the cutting machine, in particular in addition to cutting the sticker in a through-cut cutting mode of the cutting machine,

   wherein the sticker comprises a cover layer (100) and an adhesive layer (101), wherein the sticker backing comprises an adhesion-reducing layer (111) and a backing layer (110),

   wherein the adhesive layer adheres detachably to the adhesion-reducing layer, wherein within the scope of the kiss-cut cutting mode the cutting machine knife is automatically guided by the cutting machine in a cutting direction (S) along the sticker and in this process cuts through the sticker entirely and the sticker backing not at all or only partially,

   optionally wherein, in the through-cut cutting mode, the cutting machine knife is automatically guided by the cutting machine in a cutting direction (S) along the sticker and in so doing completely cuts through the sticker and the sticker backing entirely,

   wherein the cutting machine knife comprises:

   - a holding section (6) for inserting the cutting machine knife into a knife holder of the cutting tool,

   - a longitudinal axis (L) disposed at a right angle to the cutting direction,

   - a blade having a cutting edge (7) and a back (8), wherein the cutting edge, when viewed in a plane defined by the cutting direction and the longitudinal axis, forms with the cutting direction a first angle (W1) which is less than 90°,

   characterized by

   an intermediate zone (9) located between the cutting edge and the back, which, again when viewed in said plane, forms with the cutting direction a second angle (W2) of between 130° and 170°, wherein the intermediate zone (9) forms a wedge-shaped triangular surface which extends from the tip (12) to the back (8).
2. Cutting machine knife (3) according to claim 1, wherein the second angle (W2) is between 140° and 160°, in particular 150°.
3. Cutting machine knife (3) according to one of the preceding claims, wherein the first angle (W1) is less than 70°, in particular between 20° and 65°, especially 35°, 45° or 60°.
4. Cutting machine knife (3) according to one of the preceding claims, wherein the blade comprises, between the cutting edge (7) and the intermediate zone (9), a tip (12) which is pointed or rounded, in particular wherein the cutting edge and the intermediate zone enclose a third angle (W3) resulting from a subtraction of the second angle (W2) from the first angle (W1).
5. Cutting machine knife (3) according to claim 4, wherein the blade tapers along the longitudinal axis (L) and relative to an axis perpendicular to the longitudinal axis and to the cutting direction, towards the tip (12) at least on one side, in particular on both sides, in particular in a linear or curved concave or convex manner.
6. Cutting machine knife (3) according to one of claims 4 and 5, wherein a normal distance of the tip (12) from the longitudinal axis (L) is less than 0.04 mm, in particular 0.02 mm, especially 0.01 mm.
7. Cutting machine knife (3) according to one of the preceding claims, wherein the back (8) tapers parallel to the cutting direction (S) and with respect to an axis perpendicular to the longitudinal axis and to the cutting direction, at least on one side, in particular on both sides, in particular in a linear or curved concave or convex manner.
8. Cutting machine knife (3) according to one of the preceding claims, wherein the longitudinal axis (L) is an axis of symmetry of at least part of the cutting machine knife, in particular of a central shaft, and wherein the axis of symmetry passes through the back (8) with a tolerance of -0.01 mm to +0.01 mm, in particular wherein the back extends parallel to the longitudinal axis.
9. Cutting machine knife (3) according to one of the preceding claims, wherein the intermediate zone (9) between the tip (12) and the back (8) has a length (Z) which is less than 0.04 mm, in particular between 0.03 mm and 0.01 mm, especially 0.02 mm.
10. Cutting machine knife (3) according to one of the preceding claims, wherein at least one of: the cutting edge (7), the intermediate zone (9) and the back (8), again when viewed in said plane, extends in a linear or curved concave or convex manner.
11. Cutting machine knife (3) according to one of the preceding claims, wherein the cutting machine knife has a length of between 10 mm and 30 mm, in particular a length of less than 20 mm.
12. Cutting machine knife (3) according to one of the preceding claims, wherein the cutting edge (7) has a depth (T) along the longitudinal axis (L) of between 0.5 mm and 3 mm, in particular a depth of between 1 mm and 2.6 mm.
13. Cutting machine knife (3) according to one of the preceding claims, wherein the holding section (6) has a diameter of between 2 mm and 4 mm, in particular a diameter of 3 mm.
14. Use of the cutting machine knife (3) according to one of claims 1 to 13 inserted into a cutting machine (1) with cutting tool.

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