Punching tool

Abstract

A stamping tool formed from a steel strip and method of forming the stamping tool. The stamping tool is formed from a steel strip shaped on a narrow side with a cutting part having a cutting edge. The stamping tool includes a back part with a contour in cross section on a narrow side of the steel strip, recesses shaped in the back part with free spreading of the material to be transverse to a longitudinal extension of the steel strip and perpendicular to lateral surfaces of the steel strip, such that an extent of the spreading is smaller than a thickness of the steel strip, and undeformed regions located between the recesses.

Claims

1. A stamping tool formed from a steel strip having a height extending between a first narrow side and a second narrow side, and a longitudinal extension transverse to the height and a thickness in a width direction perpendicular to the height and the longitudinal extension, the first narrow side being shaped with a cutting part having a cutting edge, the stamping tool comprising: a back part on the second narrow side of the steel strip having deformed regions and undeformed regions; the undeformed regions located between the deformed regions; the deformed regions forming recesses extending in the longitudinal extension direction that have been shaped in a chipless manner in the back part, and wherein the recesses have bottoms located at a depth t below the undeformed regions, and the bottoms of the recesses have thicknesses in a width direction perpendicular to the height and the longitudinal extension greater than thicknesses in a width direction perpendicular to the height and the longitudinal extension of the undeformed regions at the depth t.

2. The stamping tool according to claim 1 being a cutting rule.

3. The stamping tool according to claim 1, wherein the strip steel is at least one of at least partially thermally treated and/or quenched and tempered.

4. The stamping tool according to claim 1, wherein the contoured material of the back part comprises one of a convex contour or a contour having plural projecting convex regions.

5. The stamping tool according to claim 1, wherein the recesses are shaped in a chipless manner by cold forming or embossing; and the undeformed region between the recesses is structured to be plastically deformable with a startup of the tool.

6. The stamping tool according to claim 1, wherein the recesses have a depth within a range of one of 5 m to 80 m and 20 m to 50 m.

7. The stamping tool according to claim 1, wherein a ratio of a longitudinal extension of the shaped recess to a longitudinal extension of the undeformed region is within a range of between one of 1.0 to 4.9 and 1.5 to 3.0.

8. The stamping tool according to claim 1, wherein a distance between two recesses or two undeformed regions is within a range of one of 0.1 mm to 0.95 mm and 0.35 mm to 0.65 mm.

9. The stamping tool according to claim 1, wherein the contour of the back part in cross section comprises at least one of rounded or polygonal regions when viewed in the longitudinal direction.

10. The stamping tool according to claim 1, wherein the steel strip comprises a strip body structured with: low-alloy steel with an inner zone having a carbon content between approximately 0.3% by weight to approximately 0.95% by weight; a fine structure achieved by a conversion in the lower bainite range; a hardness within a range of 280 to 480 HV; and a surface decarburization zone with a depth on the lateral surfaces within a range of one of 0.01 mm to 0.05 mm and 0.02 mm to 0.04 mm, wherein the undeformed regions to a depth of no more than 95 m have a tempering structure formed at a temperature between 300 C. and the austenite formation temperature of the material.

11. The stamping tool according to claim 1, wherein the steel strip is structured to be at least one of at least partially thermally treated and/or quenched and tempered, and the cutting region has a hardness of greater than one of 52 HRC or 550 HV and a rounded cutting edge with a radius within a range of between 0.004 mm and 0.05 mm.

12. The stamping tool according to claim 11, wherein the cutting edge has a cutting surface angle within a range of 50 to 100.

13. The stamping tool according to claim 12, wherein at least one lateral surface is formed towards the cutting edge with a primary and a secondary facet.

14. A stamping tool formed from a shaped steel strip having a height extending between a first narrow side and a second narrow side, a longitudinal extension transverse to the height and a thickness in a width direction perpendicular to the height and the longitudinal extension, the first narrow side being shaped with a cutting part having a cutting edge, comprising: a back part on the second narrow side of the steel strip having elevations and undeformed regions located between the elevations; the elevations being shaped in a chip less manner by recesses formed along the longitudinal extension in at least on one lateral surface of the back part, wherein the elevations have peaks and the undeformed regions have bottoms located a depth t below the peaks, and the bottoms of the undeformed regions have thicknesses in a width direction perpendicular to the height and the longitudinal extension greater than thicknesses in a width direction perpendicular to the height and the longitudinal extension of the elevations at the depth t below the peaks, and wherein the elevations are plastically deformable with a startup of the tool.

15. The stamping tool according to claim 14, wherein the elevations over the contour of the back part are formed by deformation of the lateral surfaces at an angle to one another, have an extent of 20 m to 90 m, and are spaced apart by a length of 0.1 mm to 0.95 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is explained in greater detail with exemplary embodiments, each of which represents only one way of carrying out the invention, and described based on drawings below.

(2) FIG. 1 illustrates a cutting rule in cross section;

(3) FIG. 1a illustrates a rounded convex contour of a back part in cross section;

(4) FIG. 2 illustrates a plastically deformed back part in cross section;

(5) FIG. 2a illustrates a plastically deformed back part in elevation;

(6) FIG. 3 illustrates a convex region of a back part deformed with free spreading in cross section;

(7) FIG. 3a illustrates the convex region of FIG. 3 in elevation;

(8) FIG. 4 illustrates an embossing tool;

(9) FIG. 5 illustrates a view of machined recesses in the back part;

(10) FIG. 6 illustrates a view of recesses formed in a chipless manner by embossing in the back part;

(11) FIG. 6a/b illustrates a local enlargement of FIG. 6 and a contour line over the recesses in the back part;

(12) FIG. 7 illustrates a contour of a back part with recesses formed in some parts in a chipless manner on the lateral surfaces of the cutting rule in cross section; and

(13) FIG. 7a illustrates a back part according to FIG. 7 in elevation.

(14) FIG. 8 illustrates a polygonal convex contour of a back part in cross section;

DETAILED DESCRIPTION OF THE EMBODIMENTS

(15) FIG. 1 shows diagrammatically in cross section a cutting rule 1 with a back part 2 shaped in a rounded convex manner 211 and, lying opposite, a cutting part 3 with a cutting edge 31, which has a radius 311. Cutting edge 31 can be formed with, e.g., a primary 33 and secondary 34 facet to define a cutting surface angle , within a range of 50 to 100. At least one lateral surface can be formed towards the cutting edge with a primary and a secondary facet.

(16) FIG. 1a shows in cross section a back part 2 of a cutting rule with two regions 21, 21 projecting in a convex manner. FIG. 8 shows a back part 2 shaped in a polygonal convex manner 211.

(17) FIG. 2 shows a shaped back part 2 with free spreading (or plastic material displacement) 22 of the material with a shaping by a tool with a shaping force direction P in cross section (FIG. 2) from FIG. 2a. With a thickness D of the cutting rule 1, an enlarged width B is formed with a depth of impression t by plastic material displacement 22 in the convex back part 2, which, however, has a smaller extent than the rule thickness D.

(18) FIG. 2a shows in elevation a cutting rule 1 with a plastic embossed depth 4 in the convex region on the back part 2. The undeformed back part 2 has a length a, the plastically deformed region has a length with a designation b.

(19) FIG. 3 and FIG. 3a show essentially the same images as in FIG. 2 and FIG. 2a, but the back part 2 comprises two contour regions formed by scraping with free material spread 22 and a total width B.

(20) FIG. 4 shows a tool or stamping wheel for perpendicular deformation for a back part (2) of a cutting rule 1.

(21) FIG. 5 shows in elevation according to the prior art recesses ground into a tool or into a back part 2 of a cutting rule 1, wherein the ground flutes 5 run in the thickness direction of the cutting rule 1.

(22) FIG. 6 shows embossed recesses according to the invention in the back part 2 of a cutting rule 1.

(23) FIG. 6a shows the embossed recesses 4 in an enlarged form. The scraped flutes 6 can still be seen in reduced form in the surface of the embossed flutes 4. Outside the recesses, the scraped flutes convey the material flow with a free spreading in their longitudinal extension through the wave form or bulges in the region of the embossed recesses 4.

(24) FIG. 6b shows a measured height progression in the central convex region 21 of the back part 2 of a cutting rule 1.

(25) FIG. 7 and FIG. 7a show in cross section (FIG. 7) and in elevation a back part 2 with embossed recesses 4 on the lateral surfaces of a cutting rule 1. Elevations 23 with a height oft are formed in a length a by the material flow with a free spread due to the embossed recesses 4 in the lateral surfaces of a cutting rule 1 at an angle to the lateral surface 1, which were made by tools with a force direction P.sub.1 and P.sub.2. A distance b of the elevations 23 from one another is determined by the tool shape.

(26) A list of reference characters is designed to facilitate the assignment of the functional regions and parts of the tool in the images.

(27) They represent: 1 Cutting rule 2 Back part 21 Convex regions 22 Spread material 23 Elevation 3 Cutting part 31 Cutting edge 311 Cutting edge radius 4 Embossed recess 5 Machined flutes 6 Scraped flutes B Freely spread contour D Width of the cutting rule P, P.sub.1, P.sub.2 Shaping force a Length of the projecting region b Length of the recess