EP1110685B1 - Cutting and scoring tool - Google Patents

Abstract

Cutting and fold-lining tool primarily for production of card-board packaging units is provided with chamfered surfaces (6) whose convex curvature (6a) next to the cutting edge (4) is gradually transformed into a concave curvature (6b) located nearer to the base section (2).

Description

The invention relates to a cutting and scoring tool, preferably for pressure cutting, according to the generic term of Claim 1 and use of such a tool according to the preamble of claim 23.

Such tools are e.g. in the cardboard industry used to cut from a cardboard or cardboard material for boxes or boxes (e.g. cigarette boxes) manufacture. This usually happens by means of punching devices that the blade-shaped tools with at least during the cutting process to the material level Take up the vertical blade so that it is on one side of the blade existing chamfer starting with the cutting edge perpendicular to the material plane by lifting or rotating movement penetrates into the material. This allows the blanks cut out on the one hand and also on the other hand to form fold lines by only partially cutting out be scored, the fold lines unfolding the cut, e.g. enable to a box.

The cutting edge (tip section) of the cutting and scoring tool has the shape of a wedge, the side surfaces form a wedge angle. The effect of such a cutting edge is, for example, in Spaethe-Trzebiatowsky: metalworking Vol. 1, Olten - Freiburg i. Br., 6th ed. 1965, p. 67 described. This effect depends on the position and movement the cutting edge relative to the workpiece. In the during vertical cutting the good cut or separated, while at oblique Employment chips would be separated. Through the angry The wedge is driven into the material by cutting force. He has to displace the material. The one to be overcome Cutting resistance depends on the strength properties of the material to be cut, the size of the Wedge angle and the effective cutting edge length. With slim Wedge with a small wedge angle means less material has to be displaced than with a large wedge angle. The cutting resistance is therefore lower. However, the slim wedge has one lower mass, breaks more easily or the cutting edge becomes blunt slightly off. When cutting, the cutting force breaks down into Wedge force components directed at right angles to the side surfaces. The resulting friction requires a higher one Effort. The wedge force components are divided into vertical ones and horizontal partial forces (normal and transverse partial forces). The vertical forces cause the propulsion, a crack may appear in front of the cutting edge form or a so-called bursting in the punched Material can occur. Exceed the horizontal Partial forces (shear force components) the strength of the Punched good, so it is torn apart. There is a Fracture with a rough fracture surface, while the actual cutting surface should be smooth.

In the magazine "Paper + plastic processor" No. 8, 1994, page 12 is a balance of forces for a symmetrical trained cutting and scoring tool for pressure cutting reproduce that over that of Spaethe-Trzebiatowsky specified considerations, insofar as this It also takes into account the frictional forces acting on the wedge and counteracting the cutting force (here called knife force) Punching force should be taken into account. It is carried out that the knife force to be applied the necessary punching force to destroy the material and the vertical resulting from the material displacement components of the wedge and Frictional forces should be composed, the frictional force in each case by multiplying an average sliding friction number is calculated with the wedge force. From this too Balance follows that with a slim wedge with a small Wedge angle a lower cutting resistance occurs than for a wedge with a larger wedge angle. It also becomes the balance clearly that the necessary to be applied Knife force by reducing the coefficient of sliding friction can reduce. As a corresponding technical Measures are therefore. on the one hand double bevels with two effective wedge angles and on the other hand a lubricating lacquer coating etc. of the wedge-shaped tip section proposed.

DE-A-2 743 258 states that for cutting of cardboard, paper, etc. normally blades made of hardened Steel are used in the usual grinding have a roughness of a few micrometers or less and have to be replaced and re-ground more often. Although it also blades with a tungsten carbide cladding for such purposes, which have this disadvantage do not have, however, these statements are extraordinary expensive and little used. Purpose of the object of registration this document is therefore an improvement of hardened steel blades for punching / cutting machines in such a way that their service life is extended and at the same time the penetration of the blade into the material to be machined. Punched material is facilitated. It will be a hardened blade Steel described a first ground side surface with a maximum roughness of 0.9 µm, which is an angle of 19 to 22 degrees with a flat one Blade side forms, and which continues to be a second ground Side surface with a maximum roughness of 0.02 µm, which is an angle with the flat blade side forms, which is 1 to 5 degrees larger than the angle the first ground side surface. The desired So improvement is particularly through a very pronounced Smoothness and fineness of the blade, i.e. by a sometimes extremely low surface roughness achieved, with what considerable manufacturing effort is involved.

Especially when processing foil or aluminum-clad Cardboard forms with the processing known cutting and scoring tools edge dust on the Cut, often called "lint". That punch dust must be laboriously manual work, with brushes, Orbital sander, compressed air or similar tools from the blanks are removed. Therefore are different technical solutions to avoid edge dust are proposed Service.

In the production of the also under the name "cutting lines" known steel cutting and scoring tools, such as it is described, for example, in DE-A-3 919 536, a steel strip is first machined, such as scraping or blasting, bevelled with the cutting or scoring edge form. Then the steel band in the tip section, hardened especially in the area of the cutting and scoring edge. This hardening is done by heating to the required Hardening temperature and a subsequent defined Cooling down. The heating can advantageously in the induction process with high frequency, because the Hardening especially in the area of the cutting and scoring edge only with a small depth in the thickness of the steel strip must be done. The area of the cutting or scoring edge is preserved thereby in a continuously executable work step the required hardness so that the cutting and Scribing tools also have a long service life. At the High frequency heating up to the required hardening temperature however, the surface is tarnished and scaled of the steel strip. Such scaling on the surfaces of the bevels affect the smooth indentation in cardboard, paper or the like, so that on the cut edges of the cardboard, paper or the like cut dust and fraying arise. The tarnishing and scaling can, as DE-A 3 919 536 proposes, by a protective gas treatment be counteracted.

If you look at the cross section of the blades more familiar Cutting and scoring tools, so a variety of different Determine shapes. The cross section can be symmetrical or be asymmetrical (see US-A-2 276 376). The blade can have a concave shape, such as according to US-A-2 211 213 in the base section, or a convex shape such as corresponding to US-A-2 049 157 or US-A-2 276 376, have. Common to all these known blades however at least one chamfer in the area of the blade tip, which is always flat.

An exception to this characteristic is a the German utility model DE-U-296 16 585 used as a generic Cutting and scoring tool in which the chamfer is such a has convex curvature that each towards the Cutting edge on the bevel with a tangent Cutting direction through the axis of the cutting edge includes an angle that is less than 90 °.

DE-A-29 07 325 relates to a cutting roller for producing profiled inner and outer cuts on moving webs or individual blanks from paper or the like, in particular for the production of blank envelopes on envelope making machines, consisting of a base body which carries a web-shaped knife, the latter Processing corresponds to the contours of the format to be cut. The knife consists of one or more welding beads placed side by side and one above the other on the base body. By milling a sloping roof in the upper, somewhat more strongly held area of the web, the weldable caterpillars can be made into cutable knives without further rework. The sloping roof, which can also be understood as a _" chamfer", has no curvature, but is flat. The foot area of the welding bead has an indentation in the lower area which is not involved in the cutting process.

EP-A-0 418 768 describes a stamped sheet made of sheet steel, a process for its Manufacture and a tool for performing the method described. The Punching plate has at least one protruding from the front, one each Cutting edge carrying web, the normal distance of the cutting edge from the Back of the stamping plate by a nominal size with a tolerance of 0.04 at the most mm varies. On the back is material in at least one area of the webs removed or filled and / or on both flanks of the punched edge directly on this, one depression each by pressing or one Bulge arranged. By pressing or upsetting the Punching sheet is first connected to the punching edge using a spherical curved carbide pin creates a concave curvature. By the material displacement occurs - adjoining the concave area - a convex bulge, which in turn in the original (undeformed) contour the flanks merges. From the description of the cutting process and the type and the geometry of the material to be cut results in the fact that the in Cutting direction behind the convex area is not part of it is a cutting bevel.

The majority of the known cutting and scoring tools has in particular either a scraped or a ground bevel (FR-A-1 483 301, DE-A-2 304 237, DE-A-2 743 258), i.e. for the preliminary product, a cold-rolled, hardened and tempered steel strips made of spring steel, the chamfer is either by grinding or by Cockroaches formed. Scraping means one machining, in which the to be machined Workpiece relative to a fixed tool, e.g. a hard metal tool or the like, i.e. the steel strip becomes the longitudinal bevel pulled through at least one drawing station.

EP-A-0 234 009 describes the advantages and disadvantages of known either ground or scraped generic Cutting and scribing tools described. The honed Bevel has a minimal hollow section, which results in excellent sharpness, so that a low punching pressure is required. However, the dimensional accuracy such a chamfer not for all purposes satisfactory. Because of their scraped bevels Very good dimensional accuracy in the drawing process, so that they are used for high demands on dimensional accuracy become. Since such chamfers are weakly convex, their sharpness is low and they do not have a cutting effect but pressing on the material, so that higher punching pressures (Knife forces) are required. Such cutting tips can also have a radius, a fillet or a Have flattening. In the above writings is therefore a cutting and scoring tool, or a manufacturing process proposed for a tool that is particular due to an extraordinarily high dimensional accuracy, i.e. a very low height tolerance, distinguishes what for the above the use case described is particularly important than the cutting edge is exactly linear and parallel to the plane of the material to be cut and / or scribed must run, otherwise only an uneven Cutting or scoring would be achieved. Further the tool known from EP-A-0 234 009 has one increased tool life, and there is the formation of cut dust largely avoided. The cutting and scoring tool has one in order to achieve this, starting from the tip of the bevel scratch-free, polished surface, which is on the one on a long side of the blade trained scraped bevel. The bevel angle the fine-tuning is advantageous Execution approx. 45 ° to 60 °.

Punch knives are presented in EP-A-0 715 933 differ from all those described above in that that the cutting tip is deliberately aimed Has rounding. This rounding is considered the crucial one Viewed feature by which prevented should be that the cutting edge is damaged in case of overpressure, i.e. is flattened and a ridge arises. The resilience such a rounded cutting edge is three times higher than that of a pointed cutting edge, the cut quality would also be preserved over long runs. At a Such execution must have high cutting forces be assumed. Such a blunt edge is created due to the manufacturing process also when scraping chamfers the blade.

• Einhaltung der geometrisch genauen Schnittfläche;
• keine, z.B. durch Messerbeschädigungen verursachte, Streifenbildung in Schnittrichtung;
• keine, z.B. durch wechselnde Härte über die Höhe eines zu schneidenden Stapels hervorgerufenen, wellenartigen Ausbuchtungen;
• minimale Rauheit der Schnittfläche;
• keine Rißbildung bzw. Bersten vor der Schneidkante;
• minimaler Anfall von Schneidstaub, als dessen Hauptursache eine zu hohe Rauheit des Schneidwerkzeugs angesehen wird.

From the above information, the high demands on the tools used for cutting and scoring are evident, which can be summarized as follows with regard to the requirements for the quality of the cut material:

• Compliance with the geometrically precise cutting surface;
• no streaking in the cutting direction, for example caused by knife damage;
• none, eg wave-like bulges caused by changing hardness over the height of a stack to be cut;
• minimal roughness of the cut surface;
• no cracking or bursting in front of the cutting edge;
• minimal amount of cutting dust, the main cause of which is considered too high roughness of the cutting tool.

• hohe Schneidhaltigkeit, und zwar
  • eine sehr geringe Höhentoleranz der Klinge, weil die Schneidkante genau linear sowie parallel zu der Ebene des zu schneidenden und/oder zu ritzenden Materials verlaufen muß;
  • Maßhaltigkeit der Fase;
  • geringe, aber hinsichtlich der Herstellungskosten optimierte Rauheit der Klinge;
• hohe Standzeit des Werkzeugs durch
  • Festigkeit der Klinge - insbesondere darf diese auch bei überhöhtem Schneiddruck nicht beschädigt werden;
  • Härte der Klinge zur Gewährleistung einer hohen Verschleißfestigkeit;
• Gewährleistung eines optimalen Ablaufs des Schneidvorgangs hinsichtlich
  • eines schneidenden (nicht drückenden) Eindringens in das Stanzgut;
  • eines geringen Stanzdruckes durch minimalen Schnittwiderstand und kleine Reibungskräfte beim Schneiden;

• möglichst niedriger Herstellungsaufwand;
• kurze Zurichtzeiten bei der Bemesserung der Stanzformen.

The following requirements for the cutting tools are then derived from the requirements for the quality of the clippings:

• high edge retention, namely
  • a very low height tolerance of the blade because the cutting edge must be exactly linear and parallel to the plane of the material to be cut and / or scribed;
  • Dimensional accuracy of the chamfer;
  • low roughness of the blade, but optimized in terms of manufacturing costs;
• long service life of the tool
  • Strength of the blade - in particular, it must not be damaged even with excessive cutting pressure;
  • Blade hardness to ensure high wear resistance;
• Ensuring that the cutting process runs optimally
  • a cutting (not pressing) penetration into the punched material;
  • a low punching pressure due to minimal cutting resistance and low frictional forces when cutting;

• production costs as low as possible;
• short preparation times when dimensioning the dies.

Through the above, from the German utility model DE-U-296 16 585 known cutting and scoring tool already met this requirement profile to a high degree, however, it has been shown that this is still not to be neglected There is room for improvement.

The invention has for its object a cutting and To create scribing tool of the type described at the outset, with which these are partially antagonistic to each other cautious demands can be met even better and also a corresponding advantageous use of the to indicate the generic type.

This task is made appropriate by the technical measures of the features of claims 1 and 23 solved.

According to the invention, this occurs when cutting or scoring with advantage to a swelling and swelling of the occurring Forces such that in the convex area of the side of the cutting edge starting when penetrating into the Good to be cut the ratio of one in the cutting direction pointing knife force perpendicular to the cutting direction standing lateral force does not initially decrease, in particular but grows steadily while penetrating further in the concave area the ratio of the in the cutting direction pointing knife force perpendicular to the The transverse direction of the cutting direction does not increase afterwards, but especially steadily decreasing. That way comes in optimally during the separation process of the good temporarily cutting, temporarily the pressing effect of the tool predominantly to the advantage, whereby the penetration behavior of the tool according to the invention in the material to be processed At its best. Especially through the concave area among other things, there is a possible formation of bulges of the material to be cut on its surface.

The knife force to be applied is when penetrating into the Good to be cut due to the curved contour of the chamfer depending on the distance h of the point of action of the wedge force component from the cutting edge, as the effective one Wedge angle, e.g. as a cutting angle from both sides in Tip section each to the bevel in the direction of Cutting edge of tangents can be defined, changes constantly depending on this distance h. This constant change is advantageous avoided that during the separation or scribing process in Tool and sudden changes in the material to be processed the effective forces or mechanical stresses could occur.

If the blade longitudinal sides of a tool according to the invention, in particular in the region of the chamfers, are symmetrical with respect to a central axis running through the cutting edge in the cutting direction, it can be shown that the knife force can be expressed as follows: F M * ( H ) F Q * ( H ) = 2tan ( β 2 + ρ)

Here ρ is the so-called friction angle, which increases ρ = arctanµ can be calculated, and F _M ^* the knife force, F _Q ^* the transverse force, β the wedge angle, h the vertical distance of the cutting edge. and µ the sliding friction number. It should be noted, however, that equation (1) along the bevel - strictly speaking - leads point by point to different values for the knife force F _M ^* and the lateral force F _Q ^* , since the shape of the contour of the bevel is not constant. It is therefore necessary to switch from an integral view to an infinitesimal view in this balance of forces, in which case the forces (knife force F _M ^* , transverse force F _Q ^* ) are to be understood in each case as specific quantities. All sizes are therefore related to infinitesimally small values of the distance coordinate h running counter to the cutting direction from the cutting edge, and the total force values only result from integration of the cutting edge (value h = 0) up to the effective maximum vertical distance (h = h _max ) the point of action of the wedge force at the respective moment of the cutting or scribing process.

From (1) and (2) - depending on the underlying task - target functions and boundary conditions for an optimization calculation (formation and solution of differential equations) can be derived, by means of which the detailed course of the function β (h), which is optimized under the relevant aspect, (Function type and parameters) can be determined. For example, such an objective function can consist in that the quotient of knife force F _M and lateral force F _Q assumes a minimum value or remains constant when the tool according to the invention penetrates the material. An analytical expression for the function β (h) and / or F _M ^{* can also be} specified as a boundary condition, by means of which it can be taken into account, for example, whether the material to be processed is to be cut or only scratched.

In particular, this leads to the execution of a tool according to the invention, according to which Chamfer - seen in cross section - an approximately S-shaped or (on the other side) reversed S-shaped contour has and an imaginary, starting from the cutting edge Straight through a base at the transition from the tip section to the base section on the long side of the blade runs, intersects in at least three points.

Further advantageous embodiments of the invention are in the Subclaims and the following description included. Using the shown in the accompanying drawing figures The invention becomes closer to exemplary embodiments explained. 1 to 18 each show in cross section and enlarged compared to natural size, 18 different embodiments of an inventive Cutting and scoring tools.

The same in the different figures of the drawing Parts always have the same reference numerals so that they are usually only described once.

1 shows, there is a first embodiment of a Cutting and scoring tool according to the invention, preferably is provided for the pressure cut from a Blade 1, which has a base section 2 and one attached to the Base section 2 adjoining wedge-shaped tip section 3 with a cutting edge 4 and with at least one - Two in the embodiment shown - each on one Blade longitudinal side 5 formed with the other blade longitudinal side 5 a chamfer 6 including a wedge angle β. The wedge angle β is the cutting angle from both sides' in the tip section 3 each on the chamfer 6 in the direction of Cutting edge 4 created tangents T-T defines and can over an opposite to the cutting direction S from the cutting edge 4 from the current distance coordinate h, that of the respective Depth of penetration into what is to be cut or scored Well corresponds to be changeable. The one from the chamfer 6 the two sides of the blade 5, or from the tangents T-T included effective wedge angles β can e.g. steady increase with increasing distance from the cutting edge 2. or decrease.

The wedge-shaped tip section 3, each with the chamfer 6 on each blade longitudinal side 5 is advantageous in terms of one running in the cutting direction S through the cutting edge 4 Center axis X-X symmetrical. at such a symmetrical formation of the blade 1 results the wedge angle β is a double value of an angle between the on a blade longitudinal side 5 in the direction of Cutting edge 4 on the chamfer 6 tangent T-T with the Center axis X-X.

The chamfer 6 has at least two continuously merging Areas 6a, 6b, and at least one first area located near the cutting edge 4. 6a with - seen in cross section - convex curvature (wedge angle β increases) and at least one of the convex ones Area 6a adjoining the second, near the Base section 2 arranged area 6b with - in cross section seen - concave curvature (wedge angle β increases from).

The bevel 6 can - at least in cross-section in sections an approximately S-shaped or - on the other blade longitudinal side 5 an inverted S-shaped Show contour course. An imaginary one, from the cutting edge 4 outgoing straight line G-G, which through a base point F at the transition from tip section 3 to base section 2 the longitudinal side of the blade 5 runs, can be advantageous cut from the S-contour of the chamfer 6 in at least three points become.

It is also possible and advantageous that - as shown - The symmetrical on both sides of the blade 5 trained chamfers 6 in sections (in areas 6c) run parallel. Returns to a parallel course bevels 6 should however be avoided. This parallel areas 6c, which are preferably flat are formed, or others described below flat areas in the cross section of the chamfer 6 can each proportionally to the convex area 6a or the concave area 6b, depending on the arc of the S they are. Through the areas can be advantageous if necessary in coordination with the goods to be processed Extension of the tip section 3 can be achieved. This each illustrate comparisons of pairwise similar ones 1 and 2, 3 and 4 ... 17 and 18. Die areas 6c running in parallel do not contribute to being pushed apart the material of the goods to be processed, thereby advantageously forming a bulge in the material is completely prevented or at least severely restricted. The parallel areas 6c can be advantageous a length of up to 45 percent of a vertical (in Cutting direction S running) length l of the tip section 3 have.

As shown in FIG. 1, the contour of the chamfer 6 can advantageously also be designed in such a way that between the base section 2 and the area with concave curvature 6b of the chamfer 6 - in particular with a continuous transition - at least one further area 6d with convex curvature of the chamfer 6 is arranged. In the vicinity of the base section 2 there is an increased risk of breakage of the blade 1, which can be counteracted by the additional convex area 6d, so that the blade 1 easily and easily penetrates even relatively thick material to be cut. Due to this additional convex area 6d, the embodiment according to FIG. 1 has not only three but four intersection points with the imaginary straight line GG starting from the cutting edge 4. These are the points P ₁ , P ₂ , P ₃ and F. As can be seen from FIG. 1, these intersection points P ₁ , P ₂ , P ₃ , F each mark approximately the beginning and end of a convex area (6a and 6d) and of the concave region 6b, wherein - in accordance with the above definition, the flat regions 6c are each included proportionately. The convex region 6a lies approximately between the point P ₁ on the cutting edge 4 and the point P ₂ in the central region of the tip section 3, and the concave region 6b lies approximately between the point P ₂ in the central region of the tip section 3 and the point P ₃ located in the tip section 3 near the base section 2. The convex area 6d lies approximately between the point P ₃ , which is located in the tip section 3 near the base section 2, and the base point F.

The bevel 6 thus - seen in cross section - not only an approximately S-shaped or - on the other side of the blade 5 shows an inverted S-shaped contour course, but even one - seen in cross section - double S-shaped or - on the other longitudinal side of the blade 5 reverse-double-S-shaped on.

An average half wedge angle γ = β / 2 between the imaginary straight line G-G starting from the cutting edge 4 through the base point F at the transition from the tip section 3 to Base section 2 runs on the longitudinal side 5 of the blade, and the one running in the cutting direction S through the cutting edge 4 Center axis X-X can be in particular in the range of 15 ° to 45 °, preferably - as shown in Fig. 1 - at about 27 °. The ones that occur when cutting or scoring Forces oscillate through it in a way that still is described in more detail below with reference to FIG. 2 in order to an average value resulting from this angle γ and in practice for most machining tasks, which are to be carried out with a tool according to the invention, has proven to be optimal.

The blade 1 can have a thickness D in the region in the region from 0.3 to 2.5 mm, preferably about 0.7 mm, and the Tip section 3 can be vertical (in the cutting direction S running) length l in the range of 0.5 to 3.5 mm, preferably about 0.7 to 1.3 mm.

The blade 1 can preferably be made from one, from the cutting edge 4 starting at least into the convex area 6a of the tip section 3 additionally remunerated Spring band steel exist. In this remunerated area can the blade 1 in a preferred embodiment, in particular by an induction, flame or laser hardening and a subsequent one Temper, preferably at a temperature from 250 to 500 ° C, a hardness of 30 to 67 HRC.

A second embodiment of an inventive Cutting and scoring tool is shown in Fig. 2. This differs from the first version in that that the tip section 3 has a lower vertical has (running in the cutting direction S) length l and that which are formed symmetrically on both longitudinal sides of the blade 5 Chamfers 6 do not run parallel in sections.

The forces that become effective are also exemplarily illustrated in FIG. 2. As already mentioned, different values of the knife force F _M ^* and the transverse force F _Q ^{* are} present point by point along the chamfer 6, since the shape of the contour of the chamfer 6 is not constant. The sizes are each related to infinitesimally small values of the distance coordinate h running counter to the cutting direction S from the cutting edge 4 and are therefore to be regarded as force components.

2 shows in the convex region 6a of the symmetrically shaped chamfer 6 a wedge force F _K ^* acting on the material to be machined, that of the invention. Cutting and scoring tool is applied at a point P. This wedge force F _K ^* , which is perpendicular to a tangent TT to the contour of the chamfer 6 through the point P, causes a frictional force F _R ^* directed in the direction of the tangent TT to the cutting edge 4, which is the product of the wedge force F _K ^* can be quantified with a sliding friction coefficient µ. The superposition of the friction force F _R ^* and the wedge force F _K ^* results in a resulting wedge force F _L ^* , which is at an angle ρ to the wedge force F _K ^* , which can be calculated according to equation (2) above. The knife force F _M ^* to be applied at point P for the cut or scoring is composed of the two symmetrically acting resulting wedge forces F _L ^* , as can be seen from the parallel diagram of forces shown in FIG. 2 - for clarity in the lower area (shifted) , The resulting wedge forces F _L ^* , which are each at an angle β / 2 + ρ to the horizontal, have force components acting at right angles to the cutting direction S, which act as transverse forces F _Q ^* and push the material to be separated sideways. The above-mentioned equation (1) applies to the ratio of the knife force F _M ^* to the transverse force F _Q ^{* which} is dependent on the coordinate h. All (action) forces F _M ^* , F _Q ^* , F _L ^* , F _K ^* , F _R ^* shown in FIG. 2, which are applied by the tool according to the invention, are each opposed by equally large (reaction) forces which are not shown for the sake of simplicity.

It has proven to be particularly favorable if - as shown - the convex curvature in the first section 6a of the chamfer 6 is designed such that the ratio of the knife force F _M ^* acting in the cutting direction S to the material to be cut in each case penetrates into the material to be cut transverse force F _Q ^* acting at right angles to the cutting direction S decreases from the cutting edge 2 over the length h of the chamfer 6 measured in the cutting direction S from a maximum of approximately 100 to a minimum of approximately 0, preferably from a maximum of approximately 5 to a minimum of approximately 0.5. With such a course of forces, not only is a cutting penetration of the cutting edge 4 into the cardboard or the paper stack guaranteed, but it can also be worked with a comparatively low punching pressure, since the material to be cut presents only a minimal cutting resistance to the cutting tool. The course of the frictional forces F _R ^* between the blade 1 and the material to be cut can advantageously be controlled in a controlled manner by the size and the course of the convex curvature when cutting. In addition, it has also been shown that the preferred embodiment of the chamfer 6 according to the invention has a particularly favorable effect in terms of reducing the amount of cutting dust. Due to the convex design of the cutting wedge in the area of the chamfer 6, the cutting and scoring tool according to the invention has a comparatively higher strength of the blade 1 than known tools. The blade 1 can therefore not be damaged even with high cutting pressure, and in addition to improved dimensional accuracy, an extension of the tool life is also possible. An unclean cut edge in the punched good caused by knife damage is prevented.

A not inconsiderable proportion of these positive effects can also be achieved in that the concave curvature in the second section 6b of the chamfer 6 is designed such that the ratio of the knife force F _M ^* acting in the cutting direction S to the material to be cut in each case transverse force F _Q ^* acting at right angles to the cutting direction S increases from the cutting edge 4 over the length h of the chamfer 6 measured in the cutting direction S from a minimum of 0 to a maximum of approximately 100, preferably from a minimum of 0.5 to a maximum of approximately 5.

The convex region 6a and / or the concave region 6b of the chamfer 6 can in each case be delimited, for example in a production-technically simple manner, by an arc section with a radius R, which is in each case approximately 0.1 to 15 times the value of the distance P ₁ F between the cutting edge 2 and the base point F at the transition from the tip section 3 to the base section 2. For example, with a thickness D of the blade 1 of approximately 0.71 mm and an angle γ of approximately 27 °, this radius R can advantageously assume a value of approximately 1.0 mm in the convex region 6a. The respective values of such a radius R can differ from one another in the convex region 6a and in the concave region 6b. 1 and 2 there is a sharp (pointed) cutting edge 4, ie each tangent T -T applied in the direction of the cutting edge 4 to the chamfer 6 closes with the axis XX running in the cutting direction S through the cutting edge 4 An angle β / 2 which is less than 90 °. Due to the sharp cutting edge 4, the tool according to the invention easily penetrates the material to be machined from the start of the cutting or scribing process.

3 and 4 (third and fourth version) there is no sharp cutting edge 4 in front. In these versions, the cutting edge 4 each have a flat flattening 4a. In the area of this flat flattening 4a adjoins the cutting edge 4 the chamfer 6 created tangent T-T with the in the cutting direction S through the cutting edge 4 axis X-X an angle β / 2, which is exactly 90 °. This can advantageously the cutting edge 4 - for example when Dressing the tool according to the invention - highly stressed be without causing harmful tip deformations comes.

Instead of the flattening 4a on the cutting edge 4 in Longitudinal direction of the blade 1 but also a groove 4b be designed such that the cutting edge 4 over their entire length has two cutting edges 4c (fifth and sixth embodiment in Fig. 5 and 6). The cutting edge 4 can have a width b of approximately 0.005 up to 0.050 mm. The fillet 4b can preferably - As shown - at least one in its cross section include an arcuate section or by a circular arc-shaped section, the Diameter of the arcuate section of the fillet 4b corresponds at least to the width b of the cutting edge 4 and at most ten times, preferably at most about three to five times the width b of the cutting edge 4 can assume. Such an embodiment of the invention Cutting and scoring tool points in terms of force to be cut due to the two Cutting 4c with a long tool life an excellent cutting effect on. Since the cutting edge 4 has two support points on the material to be cut, on which the Distributed cutting force also occurs compared to one Cutting edge 4 with only one tip reduces wear on. The counter-punching plate is also protected. It has also been shown that with such an inventive Cutting and scoring tool a very small one Height tolerance of the blade can be achieved, which makes the Preparation of the dies (carrier plates) simplified and shortens the necessary preparation time. Another advantage exists - especially with a ground flank - in that by the cutting and scoring tool according to the invention a "lint free" cut is made that the quality requirements for the cut goods will do justice.

Furthermore, a rounding 4d (seventh and eighth embodiment in FIGS. 7 and 8) can be provided on the cutting edge 4. Even with such a design, the cutting edge 4 can be subjected to high loads without causing harmful tip deformations. The radius of the rounding can advantageously be in a range from less than 10 μm to greater than 15/100 mm. When cutting cardboard, for example, the values of the pressure load on the cutting edge 4 thus remain far below the permissible limit load of approximately 1100 N / mm ² .

Between the cutting edge 4 and the area with convex curvature 6a of the chamfer 6, at least one further area 6e with concave curvature of the chamfer 6 can be arranged with a continuous transition, as shown in FIGS. 9 and 10 (ninth and tenth embodiments of the invention). Such a region 6e can be produced, for example, by hollow grinding. Due to the additional concave region 6e, for example, the embodiment according to FIG. 9 has not only four but five intersection points with the imaginary straight line GG starting from the cutting edge 4. These are the points P ₁ , P ₂ , P ₃ , P ₄ and F. The additional concave area 6e lies approximately between the points P ₁ and P ₄ , the convex area 6a between the points P ₄ and P ₂ , while the end and start points of the remaining areas 6b and 6d lie exactly as in the first and second exemplary embodiments described above (existing flat areas 6c - FIG. 9 - are proportionally attributed to the convex and concave areas 6a, 6b.)

Like the embodiments of the invention in FIGS. 1 and 3 to 17 show, it is also possible that between the Cutting edge 4 and the base section 2 at least one Area of the chamfer 6 has a flat contour. at this area can be that of the first embodiment act described area 6c, in which the trained symmetrically on both sides of the blade 5 Chamfers 6 run parallel in sections and which are in Direction towards the base section 2 towards the convex Connect area 6a. But it is also possible and advantageous if - such as in the embodiments in Fig. 11 and 12 shown - areas 6f with a flat contour between the concave portion 6b of the tip portion 3 and the base section 2, in particular on the Foot point F, extend. (Also several other versions of the tool according to the invention show such however, sometimes less pronounced flat areas 6f.) In FIGS. 11 and 12, a flat region 6f runs from Starting point F (there in an unspecified one Angle of approximately 15 ° to the cutting direction S)) the concave area 6b and continuously merges into it. Fig. 12 shows a peculiarity that in some Special cases can occur, namely that the straight line G-G sectionally coincides with the contour of the chamfer 6.

Finally, one or more areas 6g, 6h of the chamfer 6 with a flat contour can also be arranged between the cutting edge 4 and the convex area 6a of the chamfer 6, as is the case with the embodiments according to FIGS. 3 to 8 and 13 to 16 demonstrate. 13 and 14, on the one hand, there are flat areas 6g which, like the areas 6c, also run parallel to one another (β = 0) and end in a flattening 4a at the cutting tip 4. The friction force F _M * assumes a minimum value in the parallel areas 6g. In particular, these areas 6g, in addition to the contour course of the chamfer 6 according to the invention, additionally promote what is known as "self-leveling", ie height tolerance compensation over the entire length of a tool according to the invention clamped in a punching device. Depending on the length of the parallel areas 6g at the cutting tip and the width of the flattening, up to five intersection points P ₁ to P ₅ can even occur in the contour of the chamfer 6, as shown in FIG. 14, with the straight line GG. It is also possible that the convex area 6a (including a possibly existing flat area 6h) does not intersect the straight line GG.

In the other flat areas 6h in FIGS. 13 and 14 and the corresponding flat areas 6h in the other versions mentioned - such as in FIGS. 15 and 16, in which as in FIGS. 1, 2, 9 to 12 and 17 and 18 there is a sharp cutting edge 4 - the flat regions 6g converge towards the cutting edge 4 (β ≠ 0). In all flat areas 6c, 6f, 6g, 6h, the ratio of the knife force F _M ^* acting in the cutting direction S to the transverse force F _Q ^* acting perpendicular to the cutting direction S is constant, or the transverse force F _Q ^* becomes almost zero (area 6c, area 6g in Figs. 13 and 14).

The embodiments in Figs. 17 and 18 have large ones Similarity to the exemplary embodiments in FIGS. 11 and 12 on. One difference, however, is that the 11 and 12 a convex area 6d in the tip section 3 near the base section 2 and the explanations in FIGS. 17 and 18 are not. On another difference is that the middle half Wedge angle γ = β / 2 between the imaginary, from the cutting edge 4 outgoing straight line G-G, which passes through the base point F am Transition from tip section 3 to base section 2 at the Blade length side 5 runs, and in the cutting direction S through the cutting edge 4 center axis X-X at 17 and 18 is larger.

As the geometrical relationships in the drawing illustrate, can be the respective length of the convex Area 6a or concave area 6b with advantage about 5 to 95 percent of the length l of the tip section 3 amount, the flat areas 6c, 6f, 6h on the respective length of the convex area 6a and / or concave area 6b advantageously about 0 to 85 percent can be involved.

The contours described above and shown in figures the chamfer 6 can be machined by scraping and / or at least partially produce by grinding. Also a surface treatment by etching and Eroding is alternatively or additionally advantageous possible. In particular, scraping is preferred wherein a blank for the inventive to be manufactured Tool to form the chamfer in the longitudinal direction pulled at least one hard metal tool or the like whose negative contour is the chamfer course of the tool equivalent. The negative contour acting as a patrix for the chamfer 6 can be extremely precise e.g. by electroerosive removal, such as wire EDM, be generated.

The surface of the blade 1, in particular that of the tip section 3, can be an additional finishing experienced by applying a functional layer. For this purpose, a lubricating lacquer coating, evaporation with titanium nitride, tungsten carbide plating, a coating with polytetrafluoroethylene (PTFE) or a similar measure can be provided. Such functional layers reduce friction and increase the corrosion and wear resistance of the tool according to the invention.

The invention is not limited to the foregoing Embodiments. For example, it is also possible that the blade longitudinal sides 5 with their chamfers 6 also can optionally be formed asymmetrically to each other. The concave and / or convex curvature of the chamfer 6 does not have to run in a circular arc, but can also be part an ellipse or a geometric curve with curvature (Parabola, e-function) can be executed without the Is left within the scope of the invention.

Furthermore, the person skilled in the art can take additional measures for Improving the cutting behavior of an inventive Provide tools such as the length of the Tip section 3, especially in the area of the cutting edge 4, distributed perforations, curls and / or Serrations.

reference numeral

1

blade

2

base section

3

tip portion

4

cutting edge

4a

Flattening on 4

4b

Fillet on 4

4c

Cut to 4b

4d

Rounding to 4th

5

Sound long side

6

chamfer

6a

convex area of 6

6b

concave area of 6

6c

flat area with parallel course between 6a and 6b

6d

additional convex range from 6 to 2

6e

additional concave area between 4 and 6a

6f

flat area between 6b and 3

6g

flat area with parallel course between 4 and 6a

6h

flat area between 4 and 6a

b

Width of 4b

D

Thickness of 1 (in the range of 2)

F

Base point at the transition from 3 to 2

F _K ^*

Wedge force (perpendicular to T-T)

F _L ^*

wedge force resulting from F _R ^* and F _R ^*

F _M ^*

knife force

F _R ^*

frictional force

F _Q ^*

lateral force

H

Longitude coordinate for 3

1

Length of 3

P

Force application point on 6

P ₁

Intersection of 6 with G-G

P ₂

Intersection of 6 with G-G

P ₃

Intersection of 6 with G-G

P ₄

Intersection of 6 with G-G

R

Radius of 6a, 6b

S

cutting direction

T-T

Tangent to 6

X X

Center axis of 1

β

wedge angle

γ

Angle between G-G and X-X

μ

Coefficient of friction

ρ

angle of friction

Claims (25)

1. Cutting and scoring tool, preferably for cutting by pressure, comprising a blade (1) which has a base portion (2) and a wedge-shaped tip portion (3) which connects up with the base portion (2) and penetrates into a material to be cut or scored and which has a cutting edge (4) and at least one bevel (6) which, starting from the cutting edge (4), extends for a length (I) to a foot point (F) at the transition from the tip portion (3) to the base portion (2) and which forms a wedge angle (β) at the cutting edge (4), the wedge angle (β) being defined by means of a tangent (T-T) taken to the bevel (6) in the direction of the cutting edge (4) and the bevel (6) having a region (6a) of, when seen in cross-section, convex curvature which is arranged in the vicinity of the cutting edge (4), characterised in that the bevel (6) has at least two regions (6a, 6b) which merge smoothly into one another and which penetrate into the material to be cut, namely the first region (6a) which is of convex curvature when seen in cross-section, and a second region (6b) which is of concave curvature when seen in cross-section and which is arranged in the vicinity of the base portion (2), the two regions (6a, 6b) being so formed that, when seen in cross-section, the bevel (6), or at least portions thereof, has, as a function of the side of the tip section (3) on which it is arranged, an approximately S-shaped contour or a reverse of S-shaped contour, which is intersected at at least three points (F, P₁, P₂) , namely at the cutting edge (P₁) , at the foot point (F) and at at least one point (P₂) situated therebetween, by an imaginary straight line (G-G) originating from the cutting edge (4), which straight line (G-G) passes through the foot point (F).
2. Cutting or scoring tool according to claim 1, characterised in that the convex curvature in the first portion (6a) of the bevel (6) is such that, starting from the cutting edge (2) and as penetration takes place into the material to be cut, the ratio of a blade force (F_M ^*) acting in the direction of cutting (S) to a transverse force (F_Q ^*) acting at right angles to the direction of cutting (S) decreases over the length (h) of the bevel (6) measured in the direction of cutting (S) from a maximum of approximately 100 to a minimum of approximately 0, and preferably from a maximum of approximately 5 to a minimum of approximately 0.5.
3. Cutting and scoring tool according to claim 1 or 2, characterised in that the concave curvature in the second portion (6b) of the bevel (6) is such that, starting from the cutting edge (4) and as penetration takes place into the material to be cut, the ratio of a blade force (F_M ^*) acting in the direction of cutting (S) to a transverse force (F_Q ^*) acting at right angles to the direction of cutting (S) increases over the length (h) of the bevel (6) measured in the direction of cutting (S) from a minimum of 0 to a maximum of approximately 100, and preferably from a minimum of 0.5 to a maximum of approximately 5.
4. Cutting and scoring tool according to one of claims 1 to 3, characterised in that the wedge-shaped tip portion (3) having a bevel (6) on each longitudinal side (5) of the blade is symmetrically formed in relation to a centre axis (X-X) which passes through the cutting edge (4) in the direction of cutting (S).
5. Cutting and scoring tool according to claim 4, characterised in that portions (6c, 6g), of the bevels (6) which are symmetrically formed on the two longitudinal sides (5) of the blade, extend parallel to one another.
6. Cutting and scoring tool according to one of claims 1 to 5, characterised by a form which is asymmetrical in relation to an axis which passes through the cutting edge (2) in the direction of cutting (F).
7. Cutting and scoring tool according to one of claims 1 to 6, characterised in that, in the base portion (2), the thickness (D) of the blade (1) is in the range from 0.3 to 2.5 mm, and is preferably approximately 0.7 mm.
8. Cutting and scoring tool according to one of claims 1 to 7, characterised in that the vertical (extending in the direction of cutting) length of the tip portion (3) is in the range from 0.5 to 3.5 mm, and is preferably approximately 0.7 to 1.3 mm.
9. Cutting and scoring tool according to one of claims 1 to 8, characterised in that a central half wedge-angle (y) between an imaginary straight line (G-G) originating from the cutting edge (4), which straight line (G-G) passes through a foot point (F) at the transition from the tip portion (3) to the base portion (2) at the longitudinal side (5) of the blade, and a centre axis (X-X) which passes through the cutting edge (4) in the direction of cutting (S) is in the range from 15° to 45° and is preferably approximately 27°.
10. Cutting and scoring tool according to one of claims 1 to 9, characterised in that the convex and/or concave region (6a, 6b) of the bevel (6) is in each case bounded by a portion of an arc have a radius (R) which is approximately 0.1 to 15 times the size of the length of a straight-line distance (FP₁) between the cutting edge (4) and a foot point (F) at the transition from the tip portion (3) to the base portion (2).
11. Cutting and scoring tool according to one of claims 1 to 10, characterised in that the cutting edge (4) is of a pointed configuration, i.e. a tangent (T-T) taken to the bevel (6) in the direction of the cutting edge (4) or, where there is a plane region (6h) of the bevel (6), the bevel (6) itself, makes, with an axis (X-X) passing through the cutting edge (4) in the direction of cutting (S), an angle (β/2) which is less than 90°.
12. Cutting and scoring tool according to one of claims 1 to 10, characterised in that the cutting edge (4) has a rounding (4d).
13. Cutting and scoring tool according to one of claims 1 to 10, characterised in that the cutting edge (4) has a flattening (4a).
14. Cutting and scoring tool according to one of claims 1 to 10, characterised in that there is formed in the cutting edge (4) in the longitudinal direction of the blade (1), a flute (4b) such that the cutting edge (4) has two knife edges (4c) for its entire length.
15. Cutting and scoring tool according to one of claims 1 to 14, characterised in that arranged between the cutting edge (4) and the region (6a) of the bevel (6) which is of convex curvature, with a smooth transitions, is at least one further region (6e) of the bevel (6) which is of concave curvature, produced for example by hollow grinding.
16. Cutting and scoring tool according to one of claims 1 to 15, characterised in that, between the cutting edge (4) and the base portion (2), at least one region (6c, 6f, 6g, 6h) of the bevel (6) is of a plane contour.
17. Cutting and scoring tool according to claim 16, characterised in that a region (6g, 6h) of the bevel (6) which is of plane contour is arranged between the cutting edge (4) and the convex region (6a) of the bevel (6).
18. Cutting and scoring tool according to one of claims 1 to 17, characterised in that, arranged between the base portion (2) and the region (6b) of the bevel (6) which is of concave curvature, particularly with a smooth transition, is at least one further region (6d) of the bevel (6) which is of convex curvature.
19. Cutting and scoring tool according to one of claims 1 to 18, characterised in that the blade 1 is composed of spring steel in strip form which, starting from the cutting edge (4), is additionally heat-treated at least into the convex region (6a) of the tip portion (3) and has, in the heat-treated region, a hardness of from 30 to 67 HRC, particularly as a result of induction, flame or laser hardening.
20. Cutting and scoring tool according to one of claims 1 to 19, characterised in that the bevel (6) is shaved, ground, etched and/or eroded.
21. Cutting and scoring tool according to one of claims 1 to 20, characterised in that there is applied to the surface of the blade (1), and particularly to the surface of the tip portion (3), a corrosion-inhibiting, friction- and/or wear-reducing functional layer, such as by means of a coating of anti-friction lacquer, vapour deposition of titanium nitride, cladding with tungsten carbide, coating with polytetrafluoroethylene (PTFE), or the like.
22. Cutting and scoring tool according to one of claims 1 to 21, characterised in that perforations, corrugations and/or teeth are distributed along the length of the tip portion (3), particularly in the region of the cutting edge (4).
23. Use of a cutting and scoring tool, preferably for cutting by pressure, the cutting and scoring tool comprising a blade (1) which has a base portion (2) and a wedge-shaped tip portion (3) which connects up with the base portion (2) and penetrates into a material to be cut or scored and which has a cutting edge (4) and at least a bevel (6) which, starting from the cutting edge (4), extends for a length (1) to a foot point (F) at the transition from the tip portion (3) to the base portion (2) and which forms a wedge angle (β) at the cutting edge (4), the wedge angle (β) being defined by means of a tangent (T-T) which is taken to the bevel (6) in the direction of the cutting edge (4), and the bevel (6) having a region (6a) of, when seen in cross-section, convex curvature which is arranged in the vicinity of the cutting edge (4), characterised in that the bevel (6) has at least two regions (6a, 6b) which merge smoothly into one another and which penetrate into the material to be cut, namely the first region (6a) which is of convex curvature when seen in cross-section, and a second region (6b) which is of concave curvature when seen in cross-section and which is arranged in the vicinity of the base portion (2), with the cut extending, in the course of the cutting or scoring, over the entire length (1) of the bevel (6) and, in the process, over a contour of the bevel (6) which, as a function of the side of the tip section (3) on which the bevel (6) is arranged, is approximately S-shaped or the reverse of S-shaped, that is to say, first over the region (6a) which is of convex curvature when seen in cross-section and then over the region (6b) which is of concave curvature when seen in cross-section.
24. Use according to claim 23, characterised in that an imaginary straight line (G-G) originating from the cutting edge (2), which straight line (G-G) passes through a foot point (F) at the transition from the tip section (3) to the base section (2) at the longitudinal side (5) of the blade, intersects the contour of the bevel (6) at at least three points (F, P₁, P₂)
25. Use of a tool according to one of claims 3 to 22.

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