WO2006000460A1

WO2006000460A1 - Cutting tools or punching tools comprising cutting lines

Info

Publication number: WO2006000460A1
Application number: PCT/EP2005/006986
Authority: WO
Inventors: Anton Haas
Original assignee: Böhler-Uddeholm Precision Strip GmbH & Co. KG
Priority date: 2004-06-29
Filing date: 2005-06-29
Publication date: 2006-01-05
Also published as: DE102004031421A1

Abstract

The invention relates to a method for producing a cutting or punching tool (1), said method comprising the following steps in the cited order: (a) at least one cutting line (20) is bent into the desired end form thereof, and (b) a hardener (30) is guided along the end form of the cutting line (20) in a continuous-path manner, a tip region (26) of the cutting line (20) being selectively hardened. The invention also relates to cutting or punching tools (1), or cutting lines (20) that are produced according to the cited method.

Description

Cutting lines having cutting tools or punching knife

1. Technical field The invention relates to cutting tools or punching knives and to a method for producing cutting tools or punching knives for punching cardboard, leather and textiles or the like.

2. Description of Related Art Cardboard boxes, in particular corrugated cardboard, textiles and leather, are mostly cut by means of cutting tools on an industrial scale. To this end, cutting tools are used which punch out the desired contours of the finished part from a raw material sheet.

A cutting tool according to the prior art is produced in the following manner: grooves are placed in the mold on a base plate, usually by means of a laser, which is to have the cut-out or punched-out workpiece later. It will continue in this base mounting holes or other mounting options for Punzierstifte, punch holes or the like attached when the finished product should have corresponding elements.

On this plate, the cutting lines or cutting knives - in the following, for reasons of better readability spoken only by cutting lines - attached. For this purpose, an already ground and hardened starting metal strip is unwound from the roll and bent into the desired shape by means of suitable tools. The starting metal strip may also be in rod form. Thereafter, the pre-bent starting metal strip is pushed into the burned-in grooves of the base plate and connected to the base plate either by being pressed in or glued. The cutting lines are usually made of a steel with a tough base body, which can withstand the bending stresses when bending in the form well, and a cutting area which is hardened in the tip region, to ensure increased wear resistance during punching. In this case, the tip portion can be hardened only to a certain hardness, so that the cutting line can be reliably bent around the smallest intended radius of the desired shape. If this smallest intended radius is undershot, ie the cutting line bent more narrowly than intended, cracks or fractures may occur, especially in the hardened tip region of the cutting line. The thus specified maximum usable hardness is thus significantly lower than would be possible from the hardening technology and the material. Therefore, the cutting tools thus produced wear out quite quickly and must be replaced wer¬. Furthermore, despite the already low curing of the tip region, the smallest possible bending radius is limited in order to prevent the tip region of the cutting line from tearing or breaking. As a result, no narrow radii or corners can be punched out of the starting material with the abovementioned cutting tools.

A workshop and insufficient approach to increase the hardening of the tip area is to place the finished cutting tool in a water bath, so that only the cutting area protrudes from the water upwards. Then the cutting area is heated by hand by means of an autogenous burner and quenched with water, so that it can come to a "hardening". However, such a rough workshop procedure often results in cracks or the punching tool warps. It is also very disadvantageous that - if at all - then sets a locally very uneven hardness and a very unevenly through-hardened tip area, which thus unevenly wears. Depending on the skill of the user, however, the hardness values achieved are also below the values of the precured starting material, so that this manual method is not suitable for commercial production of a cutting or punching tool. Comparable with the above-mentioned cutting tools is the construction of punching blades, which differ from the cutting tools only by their larger dimensions and thus the greater inherent rigidity. For punching blades can therefore be dispensed with a base plate. Instead, stiffening rods or the like may additionally be provided. Such punching blades are increasingly bent by automatic benders that receive their working specifications (bending parameters) from control computers. The control computers also convert or "translate" the desired geometry of the punching or cutting lines into corresponding machine commands for the automatic bending devices, the same applies to these cutting blades with respect to their problematic hardness properties and minimum bending radii and the risk of breakage or cracking As a result, the differences between cutting knives and punching knives, which are unimportant for the invention, are not dealt with in the following: The invention can also be applied to the punching knives.

It is therefore the problem underlying the invention to provide a cutting or punching tool and a method for its production which has a higher wear resistance than the prior art, and with which it is possible to punch out particularly narrow radii or corners from the starting material ,

3. Summary of the Invention This problem is solved by a method of manufacturing a cutting or punching tool according to claim 1 or by a cutting line according to claim 12 or a cutting or punching tool according to claim 15.

In particular, it is achieved by a method for producing a cutting or punching tool, comprising the following steps in the specified range: - A -

(a) bending at least one cutting line to its desired final shape, and (b) guiding a hardening agent along the final shape of the cutting line by path, selectively hardening a tip portion of the cutting line.

It is therefore proposed first to bend the uncured and therefore relatively soft and less brittle cutting line into its desired final shape and only then to selectively harden the cutting area or parts thereof by means of a sheet-steered hardening agent. By hardening the tip area after the cutting line has been bent to its desired final shape, it is possible to achieve a hardness of the tip area which is far above the hardness of precured unbent cutting lines. Furthermore, particularly small bending radii can be achieved, which would not be producible with pre-hardened cutting lines without cracking or breaking. The path-controlled guiding enables the hardening process to be carried out automatically and precisely controlled. In particular, hardness parameters such as heating temperature and cooling time over the length of the cutting line can thus be precisely defined and maintained. Thus, a precisely defined hardness and depth of hardness at the tip or cutting area of the cutting line is achieved and uniform hardness properties are ensured over the entire length of the cutting line.

Preferably, the step of bending the at least one cutting line is carried out by means of an NC-controlled bending means on the basis of geometric data. Thus, the bends, which later determine the contour of the component to be punched out, are introduced particularly quickly and precisely into the strip material. This is particularly advantageous for punching knives that do not require a geomet¬ riebestimmende base plate.

In a preferred embodiment, prior to the hardening step, the method further comprises the step of inserting a groove into a base plate by means of a web-controlled engraving means on the basis of geometry data, the shape of the groove corresponding to the final shape of the cutting line. This will change the contour of the to be punched out component, especially quickly and accurately introduced into a base plate, which supports the cutting line, supports and prevents bending of the cutting line.

Further preferably, the method further comprises the step of inserting the cutting line into the groove in the base plate before the hardening step. The curved cutting line is introduced into the likewise contour-determining groove of the baseplate and thus fastened to the baseplate and geometrically fixed.

In a further embodiment, the step of guiding the hardening agent is carried out by means of a sheet-guided guide means on the basis of geometry data.

The geometric data of the web-controlled guiding means for the step of guiding the hardening agent are preferably based on the geometric data of the web-controlled engraving means for the step of introducing the groove or the geometry data of the NC-controlled bending means. The geometry data, which have already been used for the generation of the desired cutting contour can thus be reused for curing. This reduces the effort required for the controlled guiding of the hardener to minimal adjustments.

Furthermore, the web-controlled guide means and the web-controlled engraving means are preferably the same guide element. Thus, no additional system is needed for curing. The guide means can be used both for the production of the groove in the base plate and for guiding the hardener.

In a further preferred embodiment, the curing agent is a CW laser, a CO ₂ laser, an electron beam generator, an induction coil or a plasma generator. The engraving agent is preferably a CW laser, a CCV laser or an end mill. Particularly preferably, the engraving agent and the curing agent are the same CW laser or the same CO ₂ laser. Thus, the engraver itself can be used as a curing agent, which in turn reduces the cost of equipment.

Preferably, the method further comprises the step of exchanging an engraving optics of the CW laser or the CO ₂ laser by a hardening optics before the hardening step. In order to change the laser from engraving the groove to hardening of the cutting area, it is simply possible to use a different optical system than for engraving.

The above problems are also solved by a cutting line, which after the o.g. Procedure was made.

The cutting line preferably has a base body and a hardened tip region, which has a hardness which substantially corresponds to the maximum possible service hardness of the material used for the cutting line.

The cutting line preferably has a steel of the grade C60, the hardened tip region having a service hardness of more than 800 HV 0.5, preferably of more than 850 HV 0.5 and particularly preferably more than 900 HV 0.5. Thus, the hardness of the tip region is far above the hardness of the cutting lines of the prior art. For example, in the case of cutting lines made of the material C60, it is possible to achieve the maximum hardness of about 850 HV 0.5 which is possible by the material manufacturer. When using a laser, even values of more than 900 HV 0.5 can be achieved, since the deterrence is particularly fast due to the small-area, practically punctiform heat source.

The abovementioned problems are also solved by a cutting or stamping tool which has at least one o.g. Cutting line has.

Further preferred embodiments emerge from the subclaims. 4. Brief description of the drawings The invention will be explained in more detail with reference to the drawing. Showing:

1 shows a base plate of a cutting tool with an introduced groove.

FIG. 2 shows the base plate of FIG. 1 with a cutting line inserted into the groove; FIG. and

3 shows schematically the movement of a hardening agent during hardening of the inserted cutting line.

5. DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the invention will be described by means of the drawings.

As shown in FIG. 1, a groove 12 is milled or engraved in a base plate 10 by means of a web-controlled engraving means (not shown in FIG. 1). The shape of the groove 12 corresponds to the desired cutting profile of the cutting or punching tool to be produced.

The base plate 10 is preferably a flat plate of wood, plastic or ei¬ nem wood material, such as pressboard, MDF or the like. The Grund¬ plate could also be made of another suitable material or curved or bent for special punching or cutting tasks.

For engraving the groove 12 in the base plate 10, a web-controlled engraving agent is preferably used. For this purpose, a CW laser or a CO ₂ laser but also a conventional end mill is suitable. The power of the laser is adjusted so that a sufficient burn-in depth is achieved in the base plate 10, but it still has enough residual thickness. The laser or milling cutter is located in a suitable laser or milling head, which is preferably moved NC-controlled via the base plate 10. Instead of an NC control but also a simpler control can be used. The NC control preferably controls an XYZ portal to which the laser or milling head is attached. Alternatively, an industrial robot can be used for this purpose.

The NC control guides the laser or milling head to engrave the groove 12 on the basis of geometric data which are based on the geometry of the workpiece to be rejected.

In the groove 12, as shown in Fig. 2, a bent cutting line 20 sets einge¬ and fixed, for example glued. The cutting line 20 consisting of a band-shaped metal strip with a base body 22 and a pointed cutting area 24 (see Fig. 3). The cutting line 20 is bent in its uncured state, so that particularly small bending radii are possible without the risk of crack formation.

A preferred material for the cutting line 20 is a grade C60 steel, but any other carbon steel or tool steel can be used, which can be bent well in the unhardened band-shaped state, and in the cured state has a service life sufficient for the stamping operation ¬ points. If hardening without coolant is required, air-hardening steel grades are the material for cutting line 20.

In Fig. 3, the hardening process is shown schematically. 3 shows a detail of a part of the base plate 10 with an inserted cutting line 20. A hardening agent 30 is guided along the curved and still uncured cutting line 20 so that it can act on the cutting area 24 and at least one Tip area of the cutting area 24 hardens. The direction of movement of the hardening agent 30 is indicated by the arrow V.

The curing agent 30, like the engraving means for inserting the groove 12, may be a CW or CO ₂ laser. Depending on the desired hardening method, however, it can also be an electron beam generator, an induction coil or a plasma generator. Other curing agents are conceivable, which can cause a heat input into the cutting area 24 of the cutting line.

During the hardening process, the hardening agent 30 (in this case a laser head 30) is guided and optionally pivoted by means of an NC-controlled guiding means so that it exactly follows the cutting line 30 and hardens it in its tip region 26. For this purpose, a laser beam 32 generated by the laser 30 preferably impinges directly on the tip of the cutting line 20. Depending on the hardener used, this requires an offset "h" normal to the baseplate and possibly a twist which always controls the hardening agent normally to the respectively processed tip region 26 and thus in the direction of the curvature radius of the cutting line 20. The other parameters of the hardening process, such as processing speed, heat-up intensity, cooling rate, are integrated into the control algorithm for the hardening agent.

In the case of inductive hardening, the rotation of the hardening agent, which is guided directly "from above", to be more precise normal to the base plate plane, along the tip region 26 of the cutting line 20 is dispensed with.

After hardening, the hardened tip region 26 of the cutting line 20 has a service hardness of more than 800 HV 0.5 or preferably more than 850 HV 0.5 in the case of a steel of the grade C60. With the use of a specially pulsed CW or CO ₂ laser, hardness values of up to 900 HV 0.5 or more can be achieved by the almost punctiform and thus locally very limited heat input. The hardening agent 30 may preferably be the same as that used for the engraving process. The laser used, for example, can also be used for curing. If necessary, only the operating parameters need to be adjusted. It is also possible to swing optics into the beam path of the laser. Thus, for example, the optics for engraving the groove 12 could be replaced by a special hardening optics.

Of course, however, it is also possible to exchange the machining head for curing and to use a special laser for curing. The hardening process can also be carried out on another workstation, since the control of the hardening agent with an already existing control program for the production of the grooves 12 is only associated with a small amount of computation.

It is of course possible, especially when curing on its own processing station er¬, to take all the measures desired during curing or to set special conditions. This can be, for example, working in a protective gas atmosphere or quenching with a special medium. In the case of quenching, the quenching medium can either be integrated in the hardness head, or a second processing head can be guided at a corresponding distance from the first head, which serves for quenching.

The control data required for NC or web control can be automatically calculated from the geometry data already available for the groove by the engraving process.

The assumption of the geometry data also applies to the case of the above-mentioned punching knives, since the geometry for the NC-controlled bending machines is also already available in electronic form and by means of a relatively simple "overlay". or a transformation program for the movements of the hardener can be transformed.

Another form of cutting tools 1 of the type mentioned also uses cutting lines 20 and punching blades, which are not mounted on a flat base plate 10, but on a circular cylindrical drum or roller. The material to be cut is then pulled through between this roller and a counter-roller and is cut or embossed at designated locations.

The present invention is, of course, also applicable to this type of tool. In this case as well, the production of the grooves 12 on the drum or roller is preferably carried out by means of a device which is controlled by an NC program, so that a hardening agent can likewise be guided along the cutting line by appropriate adaptation of the NC program , In this case - if available - the data for producing the grooves 12 can be used.

Another advantage of the invention is that not only the cutting lines, but also all the other in-mold tools such as puncturing pens, punches, perforating lines / perforating knives, combination lines / combination knives and the like, can also be selectively cured. In this way, these elements are brought to the same level of hardness as the tip portion 26 of the cutting line 20, whereby the life and the set-up times of the cutting or punching tools 1 optimized and thus the corresponding costs are minimized. Bezuεszeichenhste

1 punching or cutting tool 10 base plate 12 groove 20 cutting line 22 base body 24 cutting area 26 hardened tip area 30 hardening agent or laser 32 laser beam

Claims

claims

1. A method for producing a cutting or punching tool (1) aufwei¬ send the following steps in the order given:

a. Bending at least one cutting line (20) into its desired final shape;

b. path controlled guiding of a hardening agent (30) along the final shape of the cutting line (20), wherein a tip region (26) of the cutting line (20) is selectively hardened.

2. The method according to claim 1, wherein the step of bending the at least one cutting line (20) by means of an NC-controlled bending means is carried out on the Basis of geometric data.

3. The method according to claim 1, further comprising the step of introducing a groove into a base plate by means of a web-controlled engraving medium on the basis of geometric data, wherein the shape of the groove (12) corresponds to the final shape of the cutting line (20).

The method according to claim 3, further comprising the step of inserting the cutting line (20) into the groove (12) in the base plate (10) before the hardening step.

A method according to any one of claims 1-4, wherein the step of guiding the hardening agent (30) is carried out by means of a sheet-guided guide means on the basis of geometric data.

6. The method according to claim 5, wherein the geometric data of the web-controlled guide means for the step of guiding the hardening agent (20) to the mold. geometry data of the web-controlled engraving means for the step of incorporating the groove (12) or the geometry data of the NC-controlled bending means.

7. The method according to claim 5 or 6, wherein the web-controlled Führungsmit¬ tel and the web-controlled engraving means is the same guide element.

8. The method according to any one of claims 1-6, wherein the curing agent is a CW laser, a CCV laser, an electron gun, an induction coil or a plasma generator.

9. The method according to any one of claims 1-7, wherein the engraving means is a CW laser, a CCV laser or an end mill.

10. The method according to claim 9, wherein the engraving agent and the curing agent are the same CW laser or the same CO ₂ laser.

11. The method according to claim 10, further comprising the step of exchanging an engraving optics of the CW laser or the CO ₂ laser by a hardening optics prior to the hardening step.

12. cutting line (20) produced by a method according to claims 1-10.

13. A cutting line (20) according to claim 12, comprising:

a) a base body (22); and

b) a hardened tip region (26), having a hardness which essentially corresponds to the maximum possible service hardness of the material used for the cutting line (20).

14. Cutting line according to claim 13, comprising a steel of the grade C60, wherein the hardened tip region (26) has a service hardness of more than 800 HV 0.5, preferably of more than 850 HV 0.5 and particularly preferably of more than 900 HV 0, 5 has.

15. Cutting or punching tool (1) having at least one cutting line (20) according to claims 12 - 14.