EP4240556A1

EP4240556A1 - Micro forming cutter

Info

Publication number: EP4240556A1
Application number: EP20838974.2A
Authority: EP
Inventors: Martin RUCK; Thilo HUTMACHER
Original assignee: Zecha Hartmetall Werkzeugfabrikation GmbH
Current assignee: Zecha Hartmetall Werkzeugfabrikation GmbH
Priority date: 2020-12-18
Filing date: 2020-12-18
Publication date: 2023-09-13
Also published as: WO2022128130A1; JP2023553735A; US20240051043A1; CA3200906A1; KR20230117453A

Abstract

The present invention relates to a micro forming cutter (1) for producing forming tools in tool and mould making, for example for forming fuel cell components. The disclosed micro forming cutter comprises a tool shank (2) that is designed to be received in a tool receptacle of a milling machine, and a cutting head (3) that is fixedly connected to the tool shank (2). The cutting head (3) has a plurality of cutting teeth (Z), and each of the plurality of cutting teeth (Z) has a cutting edge (S). A maximum distance (Amax) of cutting points (6, 7, 8, 9) on the cutting edge (S) from the longitudinal axis (L) is less than 0.5 mm. At least two cutting edges (S) are, at least in regions, situated so as to be radially offset from one another, wherein a radial offset (V) corresponds to a difference in the distances from the longitudinal axis (L) of such cutting points (6, 7, 8, 9) on the at least two cutting edges (S), which lie in a common plane (E) perpendicular to the longitudinal axis (L).

Description

description

"MICRO FORM CUTTERS"

technical field

[01] The present invention relates to a form cutter for

Milling of workpieces in the micro range.

background

[02] In recent years, new products such as bipolar plates for fuel cells have increased the need for ever smaller components and have placed ever increasing demands on the dimensional accuracy and surface roughness of these components.

[03] At the same time, the demand for ever smaller components is increasing

Requirements for the tools used to manufacture these components.

[04] As a result, there is a need for milling tools in the field

Micromills emerged. Milling cutters with a tool diameter of less than 1 mm are referred to as micro milling cutters. The cutting conditions of micro milling cutters cannot be compared with the cutting conditions of a larger milling cutter with a tool diameter of, for example, 3 mm, 4 mm or 6 mm. Therefore, the geometry for a micro mill cannot be determined by simply scaling down the geometry of the larger mill.

[05] Bevel milling cutters are included from 6C Tools

Known tool diameters in the range of 0.4 mm to 3 mm. For example, the chamfer milling cutter from 6C Tools with item number CM-P-1045-030-020 has eight cutting teeth, each with one cutting edge. The cutting edges have a maximum diameter of 3.0 mm and a minimum diameter of 2.0 mm. The cutting edges run at a constant angle of 45°.

The technical problem on which the invention is based is to improve the dimensional accuracy and surface roughness in the production of components in the micro range compared to known milling cutters.

Summary of Revelation

The technical problem on which the invention is based is solved by a micro-form milling cutter for the production of forming tools in tool and mold making, for example for the forming of fuel cell components. The micro-form milling cutter comprises a tool shank, which is designed to be accommodated in a tool holder of a milling machine, and a cutting head, which is firmly connected to the tool shank. The tool shank and cutting head share a common longitudinal axis around which the micro form cutter rotates during use. The cutting head has multiple cutting teeth, and each of the multiple cutting teeth has a cutting edge. A maximum distance from any cutting points on the cutting edge to the longitudinal axis is less than 0.5 mm. At least two cutting edges are arranged radially offset from one another, at least in certain areas. A radial offset corresponds to a difference in the distances from the longitudinal axis of such cutting points on the at least two cutting edges that lie in a common plane that is perpendicular to the longitudinal axis.

[08] The invention is based on the idea that

To adapt and coordinate the engagement conditions of cutting multiple cutting teeth of a micro-form milling cutter in such a way that the micro-form milling cutter can achieve a uniform and optimal dimensional accuracy on a workpiece to be machined. [09] The engagement conditions are adjusted to each other by a radial offset of several cutting edges.

[10] This can create a pre-finishing effect when machining the workpiece. The final contour of the workpiece to be machined can be pre-finished by the cutting edges, which are offset radially inwards in the direction of the longitudinal axis. The radially outermost cutting edges create the final contour on the workpiece.

[11] Cutting edges can be offset over the entire length of the cutting edge or offset only in certain areas. Accordingly, the final contour can also be created by the outermost areas of different cutting edges.

[12] Due to the offset of the cutting edges, not all of the cutting edges of the micro form milling cutter are on the outer envelope curve, but are set back somewhat depending on the position on the tool and the wrapping on the component. The envelope curve characterizes the enveloping area of all paths of any cutting points that rotate around the longitudinal axis when using the micro form cutter. The envelope curve is thus formed by the points with the greatest radial distance from the longitudinal axis, points in a common plane perpendicular to the longitudinal axis being considered in each case. This prevents chatter marks and ensures better surface quality on the component. For example, the cutting edges in the front area of the cutting head can be arranged such that the cutting edges of all cutting teeth lie on the outer envelope, whereas the cutting edges in the rear area of the cutting head can be arranged such that only some of the cutting edges of all cutting teeth lie on the outer envelope.

[13] Due to the very small distances between any cutting points on the cutting edge and the longitudinal axis, the micro form milling cutter is suitable for the precision milling of very small workpieces, such as forming tools in tool and mold making, for example for forming fuel cell components. [14] Preferably, the cutting teeth are formed integrally with the cutting head. Production is preferably carried out using laser technology from a polycrystalline diamond (PCD) blank. Material can be removed by laser ablation until the desired geometry of the cutting edge of the respective cutting teeth is left on the cutting teeth.

[15] According to a preferred embodiment, at least one cutting edge extends from a minimum distance at a cutting start facing the exposed end of the cutting head to the maximum distance at a cutting end facing the tool shank such that it has an S- having shaped section. Preferably, the S-shaped section comprises, viewed from the beginning of the cutting edge in the direction of the end of the cutting edge: a first arcuate area in which the setting angles of the cutting edge change in such a way that the cutting edge runs in an arc of a circle with a first radius, a central area in which the cutting edge runs with a constant angle of attack, and a second arc region in which the angles of attack of the cutting edge change in such a way that the cutting edge runs in a circular arc shape with a second radius. The angle of incidence of a cutting point is the angle between a tangent that touches the cutting edge at that cutting point and a line parallel to the longitudinal axis that passes through that cutting point.

[16] At least one cutting edge with an S-shaped section can be used to create the radial offset of the cutting edges and for improved adaptation of the engagement conditions.

[17] The S-shaped section of the cutting edge allows the spacing of cutting points along the cutting edge to be adjusted according to the requirements of the workpiece to be machined. Compared to a straight shape of the cutting edge, the S-shape allows different cutting points along the cutting edge to have different angles of attack. [18] Due to the S-shape of the cutting edges, it is possible for several cutting edges to be arranged in relation to one another in such a way that they are offset from one another only in certain areas.

[19] The cutting edge can only be formed by the S-shaped section. Alternatively, further sections can be connected in front of the S-shaped section and/or behind the S-shaped section of the cutting edge. For example, a section with a constant setting angle can be provided in front of and behind the S-shaped section, which connects the S-shaped section to the start of the cutting edge or to the end of the cutting edge.

[20] In another exemplary embodiment of the present invention, the first arcuate portion of the S-shaped portion curves away from the common longitudinal axis and the second arcuate portion curves toward the common longitudinal axis.

[21] Alternatively, the first arched area of the S-shaped section can be curved in the direction of the common longitudinal axis and the second arched area can be curved away from the common longitudinal axis, as a result of which the engagement conditions of the cutting points along the cutting edge can be better adapted to the workpiece to be machined .

[22] In a further exemplary embodiment of the present invention, the cutting edge lies in a plane in which the longitudinal axis also lies. In this way, the engagement conditions of the micro form milling cutter can be influenced.

[23] In a further exemplary embodiment of the present invention, the cutting edge lies in a plane which intersects the longitudinal axis. In this way, the engagement conditions of the micro form milling cutter can be influenced.

[24] In a further exemplary embodiment of the present invention, the wedge angles and/or clearance angles and/or rake angles of cutting points change at least in regions along the cutting edge. [25] The wedge angle can be variably adjusted depending on the distance and/or angle of cutting points along the cutting edge. This allows an even removal along the cutting edge and the best possible service life to be achieved. The shape and surface accuracy of the workpiece can be maintained more precisely.

[26] Furthermore, the rake and clearance angles can be adjusted along the cutting edge on the basis of changed engagement conditions for different milling tasks. The engagement conditions include, in particular, the cutting depth a _p , the cutting width a _e , the feed per tooth f _z , the cutting speed v _c and the distance from the cutting points on the cutting edge to the longitudinal axis.

[27] As a result, for example, in the area of smaller distances from cutting points to the longitudinal axis and with outer radii of the cutting edge, i.e. Radii that are curved away from the longitudinal axis, a large rake angle is applied, whereas with inner radii of the cutting edge, i.e. Radii that are curved in the direction of the longitudinal axis, and in the area of greater distances from cutting points to the longitudinal axis, a small or negative rake angle is applied.

[28] In a further exemplary embodiment of the present invention, the cutting head comprises at least 4, in particular 8 to 12 cutting teeth, which are preferably distributed evenly over the circumference of the cutting head.

[29] The cutting edges are the wear part of the micro form cutter. The more cutting edges the micro form milling cutter has, the more cutting edges share the wear and the longer the service life. A micro form cutter with several cutting edges also runs "rounder" than one with only one cutting edge. With multiple cutting edges, a smoother surface can be achieved on the workpiece to be machined.

[30] Furthermore, by using many cutting edges, the contact time of the cutting edges is greatly reduced, resulting in polycrystalline diamond (PCD) - Tools with steel for finishing can be used without any problems.

[31] In a further exemplary embodiment of the present invention, the cutting head has a group of at least two consecutive cutting teeth, the cutting edges of the consecutive cutting teeth being arranged radially offset from one another, at least in some areas. This group of at least two consecutive cutting teeth is repeated at least once in the circumferential direction of the cutting head.

[32] The smooth running of the tool and the surface quality during milling can be positively influenced by the partial offset of cutting edges and the repeated circumferential sequence of a group of cutting teeth with several cutting edges offset from one another.

[33] It is also possible to design the geometry of the cutting head in such a way that there is a radial offset of cutting edges in the rear areas of the cutting edges, in which the distances between cutting points on the cutting edge and the longitudinal axis are large. On the other hand, in the front area of the cutting edges, in which the distances between the cutting points on the cutting edge and the longitudinal axis are small, there is no radial offset of the cutting edges.

[34] In an embodiment with a total of twelve cutting edges, each of which has an S-shaped section, the cutting edges can be arranged, for example, in such a way that the cutting edges are not offset in the front area of the cutting edges, in which the distances between the cutting points and the longitudinal axis are smaller is present, whereas in the rear area of the cutting edges, in which the distances from the cutting points to the longitudinal axis are greater, there are only four cutting edges on the outer envelope. This reduces the number of teeth whose cutting edge lies on the outer envelope, from twelve in the area of the cutting start to four cutting points in the area of the cutting end. [35] The cutting edges on the cutting teeth are preferably formed in such a way that the ratio of feed per tooth to the effectively acting diameters of the cutting edges along the cutting edges is in the range of 0.8%-1.5%. As a result, the load on the cutting edges from the beginning of the cutting edge to the end of the cutting edge is as constant as possible along the cutting edge. The effective diameter of a cutting point corresponds to twice the distance from this cutting point to the longitudinal axis. The effective diameter of cutting points along a cutting edge increases from front to back along the longitudinal axis.

[36] In a further exemplary embodiment of the present invention, the minimum distance of the cutting edge in the area of the first arch area (I) is in the range of 0.1 - 0.3 mm and the maximum distance of the cutting edge in the area of the second arch area (III) in the range of 0.3 - 0.5 mm. Further, the first radius of the first arcuate portion is in the range of 0.005mm - 0.25mm and the constant angle of incidence in the central portion of the S-shaped section is in the range of 0° - 45°. Furthermore, the second radius of the second arc region is in the range of 0.1 mm - 0.25 mm, and the plurality of cutting edges are arranged radially offset from one another such that a maximum cutting edge offset (Vmax) is in the range of 0.001 mm - 0.08 mm.

[37] The design of the cutting edges according to the dimensions of this exemplary embodiment allows an optimal design of the individual cutting edges and an optimal coordination of the several cutting edges with one another, in which the offset of cutting edges in some areas leads to a pre-finishing effect and to a high degree of dimensional accuracy and surface roughness of the workpiece to be machined leads.

[38] According to a further aspect of the present invention, the technical problem is solved by a micro-form milling cutter for the production of forming tools in tool and mold construction, for example for the forming of fuel cell components. The micro form cutter comprises at least one cutting edge which extends from a minimum distance at a cutting start facing the exposed end of the cutting head to a maximum distance at a cutting end facing the tool shank such that it has an S-shaped section. The S-shaped section, viewed from the beginning of the cutting edge in the direction of the end of the cutting edge, preferably comprises: a first arcuate area in which the angle of attack of the cutting edge changes in such a way that the cutting edge runs in an arc of a circle with a first radius, a central area in which the cutting edge runs with a constant angle of attack, and a second arc region in which the angles of attack of the cutting edge change in such a way that the cutting edge runs in a circular arc shape with a second radius. The angle of incidence of a cutting point is the angle between a tangent that touches the cutting edge at that cutting point and a line parallel to the longitudinal axis that passes through that cutting point.

Brief description of the drawings

[39] Exemplary embodiments of the present invention are described and explained in more detail below with reference to the attached figures.

[40] FIG. 1 shows a side view of a micro form milling cutter according to the invention.

[41] FIG. 2 shows a front view of the cutting head of the micro form milling cutter shown in FIG.

[42] Fig. 3 shows a sectional view of the cutting tooth ZI of the cutting head shown in Fig. 2 along the section B-B, the cutting plane being arranged such that it contains the longitudinal axis of the cutting head and the cutting edge S1 of the cutting tooth ZI shown.

4 shows the sectional views of the cutting teeth Z1-Z12 of the cutting head shown in FIG. 2, each showing three sectional views in superimposed form and the multiple sectional planes such are arranged to include the longitudinal axis of the cutting head and the cutting edge S1-S12 of the respective cutting tooth Z1-Z12 shown.

[44] Fig. 5 shows the sectional views of twelve cutting teeth Z1-Z12 of another cutting head according to the invention, the sectional views being shown in superimposed form and the multiple sectional planes being arranged in such a way that they define the longitudinal axis of the cutting head and the cutting edge S1-S12 of the respective shown cutting tooth Z1-Z12 contains.

[45] FIG. 6 shows a side view of a cutting head according to a further embodiment of the invention.

Detailed description

[46] The direction along the longitudinal axis is hereinafter referred to as the front-back direction or as the longitudinal direction. The side of the micro form cutter on which the cutting head is located is referred to as the front of the micro form cutter. The side where the tool shank is located is called the rear of the micro form cutter. The direction perpendicular to the longitudinal axis is referred to as the radial direction.

1 shows a side view of a micro form milling cutter 1 according to the invention. The micro form milling cutter 1 consists of a tool shank 2 and a cutting head 3. The cutting head 3 is fixed to the tool shank

2 connected. For example, the tool shank 2 and the cutting head

3 must be firmly connected to one another by means of a soldered connection. In the front area of the cutting head 3 there are several cutting teeth Z. The tool shank 2 and the cutting head 3 have a common longitudinal axis L. The micro-form milling cutter 1 rotates about this common longitudinal axis L during use. The feed when using the micro form milling cutter shown in Fig. 1 is perpendicular to the longitudinal axis L.

[48] Preferably, the tool shank 2 is made of solid carbide (VHM). The cutting head 3 is preferably made of polycrystalline diamond (PCD) or cubic boron nitride (CBN). [49] FIG. 2 shows a front view of the micro form milling cutter 1 shown in FIG. 1. The cutting head 3 comprises a total of twelve cutting teeth ZI to Z12. Each of these cutting teeth ZI to Z12 contains a cutting edge S1 to S12. When the micro form milling cutter 1 is used, these cutting edges S1 to S12 engage in the workpiece. The micro form cutter 1 shown rotates counter-clockwise when in use. In the embodiment of the micro form milling cutter 1 shown, the cutting edges S1 to S12 run straight, ie in the direction of the longitudinal axis, from front to back. The cutting edges S1 to S12 are arranged in such a way that the beginning of the cutting edge lies at a common point on the longitudinal axis L.

[50] According to further embodiments, the cutting edge can also run obliquely or spirally from front to back.

[51] The rake face 11 can extend radially outwards from the longitudinal axis L in a straight, inclined or curved manner. The face of the cutting tooth Z over which the chip runs during machining is referred to as the face 11 .

[52] Fig. 3 shows a sectional view of the cutting tooth ZI of the cutting head shown in Fig. 2 along the section B-B, the section plane being arranged such that it contains the longitudinal axis of the cutting head and the cutting edge S1 of the cutting tooth ZI shown. The cutting edge S runs from a cutting start 4 to a cutting end 5. The cutting start 4 is in front of the cutting end 5. The

Distance A from any cutting points 6, 7, 8, 9 on the cutting edge S increases along the cutting edge S from front to back. At the cutting end 5, the distance between the cutting edge S is greatest. At the beginning of the cutting edge 4, the distance between the cutting edge S is the smallest. In the present case, the minimum distance is 0 since the cutting edge S begins on the longitudinal axis L.

[53] The cutting edge S has an S-shaped section on its course from the cutting start 4 to the cutting end 5 . The S-shaped section includes a first arc region I, in which the angle of attack oc change the cutting edge S in such a way that the cutting edge S runs in a circular arc shape with a first radius RI. The circular arc shape is curved outwards, ie away from the longitudinal axis L. The cutting points 6 and 7 are located at the beginning and at the end of the first arc region I. The S-shaped section also includes a central region II, in which the cutting edge S runs with a constant angle of incidence α. The cutting points 7 and 8 are located at the beginning and at the end of the central area II. The S-shaped section also includes a second arc area III, in which the angle of attack a of the cutting edge S change in such a way that the cutting edge S is in a circular arc shape with a second radius R2 runs. The circular arc shape is curved inwards, ie towards the longitudinal axis L. The cutting points 8 and 9 are at the beginning and at the end of the second arc region III.

[54] In front of the S-shaped and behind the S-shaped section of the cutting edge S is an area with a constant setting angle, which connects the S-shaped section to the beginning 4 of the cutting edge and the end 5 of the cutting edge, respectively.

[55] The angle of attack a is the angle between a tangent that touches the cutting edge S at the cutting point 6 and a parallel to the longitudinal axis L that runs through the cutting point 6.

[56] E shows a plane that is perpendicular to the longitudinal axis L and runs through the cutting point 8 on the cutting edge S.

4 shows the sectional views of the cutting teeth Z1-Z12 of the cutting head shown in FIG. S12 of the respective cutting tooth Z1-Z12 shown.

[58] The cutting edges SI, S5 and S9 of the cutting teeth ZI, Z5 and Z9 are the same. The S-shaped sections of the cutting edges are SI, S5 and S9 characterized by the same radii RI, R2 of the first and second arc sections and the same angle of incidence α of the central section.

[59] The cutting edges S2, S6 and S10 of the cutting teeth Z2, Z6 and Z10 are the same. The S-shaped sections of the cutting edges S2, S6 and S10 are characterized by the same radii RI', R2' of the first and second arcuate areas and the same setting angle a' of the central area, with at least one of the radius RI', the radius R2 ' and the angle of attack a' differ from the corresponding sizes of the cutting edges SI, S5 and S9.

[60] The cutting edges S3, S7 and SI 1 of the cutting teeth Z3, Z7 and ZU are the same. The S-shaped sections of the cutting edges S3, S7 and Si l are characterized by the same radii RI", R2" of the first and second arcuate areas and the same setting angle a" of the central area, with at least one of the radius RI", the radius R2" and the angle of attack a" differ from the corresponding sizes of the cutting edges SI, S5 and S9.

[61] The cutting edges S4, S8 and S12 of the cutting teeth Z4, Z8 and Z12 are the same. The S-shaped sections of the cutting edges S4, S8 and S12 are characterized by the same radii RI ", R2 " of the first and second arcuate areas and the same setting angle a " of the central area, with at least one of the radius RI ", the radius R2 " and the angle of attack a " differ from the corresponding sizes of the cutting edges SI, S5 and S9.

[62] Due to the differences in the respective radii and the respective angles of attack, the arbitrary cutting points 6, 6', 6" and 6"', which are all in a common plane perpendicular to the longitudinal axis L, can be at different distances from the longitudinal axis be spaced. The cutting beginnings 4, 4', 4" and 4"' and the cutting ends 5, 5', 5" and 5"' can lie at different points on the longitudinal axis L or be spaced at different distances away from the longitudinal axis. [63] Fig. 5 shows the sectional views of twelve cutting teeth Z1-Z12 of another cutting head according to the invention, the sectional views being shown in superimposed form and the multiple sectional planes being arranged in such a way that they define the longitudinal axis of the cutting head and the cutting edge S1-S12 of the respective shown cutting tooth Z1-Z12 contains.

[64] The cutting edges SI, S5 and S9 are identical to one another. The cutting edges S2, S6 and S10 are identical to one another. The cutting edges S3, S7 and SI 1 are identical to one another. The cutting edges S4, S8 and S12 are identical to one another. However, these four groups of equal cutting edges differ from one another, so that cutting edges SI, S2, S3 and S4 are different from one another, for example.

[65] Due to the unequal design of the respective cutting edges S1 to S12, not all cutting points of the multiple cutting edges S1 to S12 have the same distance from the longitudinal axis L if they lie in the same plane E, which runs perpendicular to the longitudinal axis L. Rather, the unequal design of the respective cutting edges S1 to S12 creates a radial offset V between the cutting edges S1 to S12. The cutting edge offset V corresponds to the difference in the radial distances of cutting points on different cutting edges S1-S12 to the longitudinal axis L. The cutting points 6, 6 under consideration 'lie in a common plane E, which is perpendicular to the longitudinal axis.

[66] In relation to the points from Fig. 5, the envelope curve is formed by the points (4,4') - 6'-(5',7'), i.e. the points with the greatest radial distance to the longitudinal axis in a plane E .

[67] Cutting point 6 is on one of the cutting edges of group S3, S7, SI 1 or S4, S8, S12. The cutting point 6' lies on one of the cutting edges of the group S1, S5, S9 or S2, S6, S10. Cutting point 6' is spaced further away from the longitudinal axis L than cutting point 6. The difference is the radial offset V. [68] Cutting point 7 lies on one of the cutting edges of group S3, S7, Si 1 or S4, S8, S12 or S2, S6, S10. The cutting point 7' lies on one of the cutting edges of the group S1, S5, S9. It coincides with the cutting end 5'. Cutting point 7' is spaced farther away from the longitudinal axis L than cutting point 7. The difference is the radial displacement V, which in this case is the maximum radial displacement Vmax.

[69] The cutting edges SI, S5 and S9 are spaced further away from the longitudinal axis L over their entire length than the remaining cutting edges or at the same distance. Accordingly, the final contour on the workpiece to be machined is determined by them.

[70] According to a preferred embodiment, the cutting teeth ZI to Z12 with the cutting edges Sl to S12 are arranged on the cutting head 3 in such a way that in the circumferential direction of the cutting head 3 unequal cutting edges Sl to S4 follow one another and this sequence of unequal cutting edges Sl to S4 in Circumferentially repeated. Correspondingly, the sequence of the unequal cutting teeth S5 to S8 follows the cutting tooth S4 in this order, the cutting teeth S5 to S8 corresponding to the cutting teeth S1 to S4 in this order. Furthermore, the sequence of the unequal cutting teeth S9 to S12 follows the cutting tooth S8 in this order, the cutting teeth S9 to S12 corresponding to the cutting teeth S1 to S4 and the cutting teeth S5 to S8 in this order.

[71] FIG. 6 shows a side view of a cutting head according to a further embodiment of the invention. In comparison to the other embodiments, the cutting edges include two further sections at the cutting end, each of which has a constant angle of incidence α. These areas are production-related, non-cutting extensions of the cutting edge. Commercial Applicability

[72] With a micro form milling cutter according to the invention, workpieces can be machined in the micro range and the highest demands on shape accuracy and surface roughness can be met.

[73] For example, a micro form milling cutter according to the invention can be used to produce forming tools in tool and mold construction, which are used to produce fuel cell components. In particular, the micro form milling cutter according to the invention is used for finishing contours when finishing such forming tools. The component height of such forming tools is generally less than 0.5 mm and the areas between the lateral contours are a maximum of 0.6 mm. The demands on the components in terms of dimensional accuracy and surface roughness Ra are very high. The dimensional accuracy is preferably in the range of less than 0.003 mm and the surface roughness Ra is preferably in the range of less than 0.2 μm.

Reference List

1 micro shaping cutter

2 tool shank

3 cutting head

4, 4', 4", 4"" start of cutting

5, 5', 5", 5'" cutting end

6, 6', 7, 7', 8, 9 cutting points

10 workpiece

11 rake face

12 main flank a, a , a", a'" angle of attack ß wedge angle

5 free angle

Y rake angle

Z, Z1-Z12 cutting tooth

S, S1-S12 cutting edge

A Distance

amine minimum distance

Amax maximum distance

V radial offset

Vmax maximum radial displacement

L longitudinal axis

E plane perpendicular to the longitudinal axis L

Ri,Ri ,Ri , Ri Radius of the first arc shape

R2, R2 , R2 , R2 Radius of the second arc shape

I first arch area

II mid range

III second arch area

Claims

Expectations

1. Micro form milling cutter (1) for the production of forming tools in tool and mold making, for example for the forming of fuel cell components

- a tool shank (2) which is designed to be accommodated in a tool holder of a milling machine, and

- a cutting head (3) fixedly connected to the tool shank (2), the tool shank (2) and the cutting head (3) having a common longitudinal axis (L) around which the micro-forming cutter (1) during use rotates, in which a) the cutting head (3) has a plurality of cutting teeth (Z) and each of the plurality of cutting teeth (Z) has a cutting edge (S), b) a maximum distance (Amax) from any cutting points (6, 7, 8, 9) on the cutting edge (S) to the longitudinal axis (L) is less than 0.5 mm, and c) at least two cutting edges (S) are arranged radially offset from one another at least in some areas, with a radial offset (V) being a difference in the distances to the Corresponds to the longitudinal axis (L) of such cutting points (6, 7, 8, 9) on the at least two cutting edges (S) which lie in a common plane (E) which is perpendicular to the longitudinal axis (L).

2. Micro form cutter (1) according to claim 1, wherein at least one cutting edge (S) from a minimum distance (Amin) at a cutting start (4) facing the exposed end of the cutting head (3) towards the maximum Distance (Amax) at a cutting end (5) facing the tool shank (2) runs in such a way that it has an S-shaped section, the S-shaped section going from the cutting start (4) in the direction of the cutting end (5 ) preferably includes: - a first arc region (I), in which the angle (a) of the cutting edge (S) change in such a way that the cutting edge (S) runs in an arc of a circle with a first radius (RI),

- A central area (II) in which the cutting edge (S) runs with a constant setting angle (a), and

- a second arc region (III), in which the angle (a) of the cutting edge (S) change in such a way that the cutting edge (S) runs in an arc of a circle with a second radius (R2), the angle of attack (a) being a cutting point (6, 7, 8, 9) the angle between a tangent touching the cutting edge (S) at that cutting point (6, 7, 8, 9) and a parallel to the longitudinal axis (L) passing through that cutting point ( 6, 7, 8, 9) is.

3. Micro form milling cutter (1) according to claim 2, in which the first curved region (I) of the S-shaped section is curved away from the common longitudinal axis (L) and the second curved region (III) in the direction of the common longitudinal axis (L) is curved.

4. Micro form milling cutter (1) according to one of the preceding claims, in which the cutting edge (S) lies in a plane in which the longitudinal axis (L) also lies.

5. Micro form milling cutter (1) according to any one of claims 1 to 3, wherein the cutting edge (S) lies in a plane which intersects the longitudinal axis (L).

6. Micro form milling cutter (1) according to any one of the preceding claims, in which the wedge angle (ß) and / or clearance angle (5) and / or rake angle (γ) of cutting points (6, 7, 8, 9) along the cutting edge (S) at least partially change.

7. Micro form milling cutter (1) according to one of the preceding

Claims in which the cutting head (3) has at least 4, in particular 8 to 12 cutting teeth (Z), which are preferably distributed evenly over the circumference of the cutting head (3).

8. Micro form milling cutter (1) according to any one of the preceding claims, in which the cutting head (3)

- has a group of at least two consecutive cutting teeth (ZI, Z2), wherein the cutting edges (SI, S2) of the consecutive cutting teeth (ZI, Z2) are arranged radially offset from one another, at least in some areas, and

- This group of at least two consecutive cutting teeth (ZI, Z2) is repeated at least once in the circumferential direction of the cutting head (3).

9. micro form cutter (1) according to any one of claims 2 to 8, wherein

- the minimum distance (Amin) of the cutting edge in the area of the first arched area (I) is in the range of 0.1 - 0.3 mm and the maximum distance (Amax) of the cutting edge in the area of the second arched area (III) in the range of 0 .3 - 0.5 mm,

- the radius (RI) of the first arc area is in the range of 0.005 mm - 0.25 mm,

- the constant angle of attack (a) in the central area of the S-shaped section is in the range of 0° - 45°,

- the radius (R2) of the second arc region is in the range of 0.1 mm - 0.25 mm, and 21

- the multiple cutting edges are arranged radially offset from one another in such a way that a maximum cutting offset (Vmax) is in the range of 0.001 mm - 0.08 mm.