SK50782010U1 - Milling tool - Google Patents

Abstract

The object of the invention is a milling tool having a tool body, a shank portion, and cutting edges adapted for machining a workpiece, the cutting edges being disposed on the tool body. Corner edges of the tool, formed at the junction of peripheral and front edges, are arranged such that the corner edges of adjacent cutting edges have different geometrical arrangements.

Description

Technical field

The object of the technical solution is a milling tool having a tool body, a shank 5 and blades adapted for machining a workpiece, the blades being located on the tool body.

BACKGROUND OF THE INVENTION

Milling tools are devices that are commonly used in machining technology to remove material from workpieces.

In FIG. 1 shows the operation of a conventional shank type milling tool.

The tool rotates about its own axis at an angular velocity ω while advancing to the workpiece at instantaneous velocity v. The milling tool S has blades arranged either parallel to the axis of symmetry of the tool S or along a helical line coaxial to the axis of symmetry. These cutting edges are the peripheral cutting edges 1 of the tool S. The pitch angle (angle between the tangent to the cutting edge and the principal axis of the tool a) of the helical cutting edge may be:

a) constant (helix with constant pitch),

(b) variable (helix with variable pitch).

In actual implementations, both variants a) and b) may be combined.

For example, in the case of a 6-blade tool, the pairs of blades have opposing edges

0 blades numbered 1 and 4, 2 and 5, 3 and 6, constant pitch angles of 60 °, 55 ° and 65 °. According to another possible 6-blade implementation, the opposite blades 1 and 4 have a constant pitch angle of 60 °, while the blades 2 and 5 have a variable pitch angle that decreases linearly from 65 ° to 55 °.

The cutting edges located on the front face of the tool are the front cutting edges 2 of the tool. Corner cutting edges 3 are formed at the intersection of the peripheral cutting edges 1 and the front cutting edges 2

5 shows the corner cutting arrangements shown in FIG. 3 to 3 d.

These typical corner cutting arrangements are as follows: a) sharp corner cutting edge;

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b) one corner bevel,

c) multiple corner bevels,

d) rounded corner edge.

A common characteristic of the conventional corner cutting arrangement is that all 5 corner cutting edges 3 of the tool S have the same geometrical arrangement (a), b), c), d)).

Working parameters such as cutting depth, cutting speed, feed speed and tool life are greatly influenced by the geometrical arrangement of the corner cutting edges.

If the tool S does not have chip grooves 4 on the cutting edges, each cutting edge removes a cutting element having a width B and a thickness H, as shown in FIG. 4a.

The conventional milling tool S often comprises so-called chip forming grooves 4.

The chip-forming grooves are formed by producing a plurality of grooves 4 having a width d between which the axial distance L is formed on the tool blades, the grooves located on adjacent blades being offset in the axial direction by a distance L / 2. Therefore, as shown in FIG. 4b, the chips removed by the individual blades will have a maximum width L-d, which is favorable with respect to the usability and workload of the tool.

The essence of the technical solution

The aim of the technical solution is to provide a milling tool that will have a longer life and better usability (under the same working conditions) than conventional milling tools and / or capable of machining operations corresponding to higher technological requirements.

The technical solution is based on the realization that the tool corner configuration has a critical impact on tool life and other technological parameters.

The milling tool according to the invention has a tool body, a shank portion and blades adapted to machine the workpiece, the blades are located on the tool body or on cutting inserts fixed to the tool body, the tool being characterized in that the corner tool blades formed on the joints of circumferential and front blades are arranged so that the corner blades of adjacent blades have different geometric shapes.

elaborated documents, reaction to the Office assessment from 25.01.2011

A preferred embodiment of the milling tool according to the invention has a shank type or disk type configuration.

Another preferred embodiment of the milling tool according to the invention has cutting inserts wherein the corner cutting edge of each cutting insert is formed by successive sections of different geometrical shape.

A further preferred embodiment of the milling tool according to the invention has a geometrical arrangement in which the tool has an even number (2, 4 ...., 2n) of blades, the odd blades (1,3, ..., 2n-1) having rounded edges. the shape and even blades (2,4, ..., 2n) have a bevelled shape.

Image overview

Known implementations of the milling tool as well as preferred embodiments of the milling tool according to the invention are further explained with reference to the accompanying drawings, in which:

In FIG. 1 shows a conventional, known shank type milling tool in a working position;

In FIG. 2 shows the blades of a known milling tool;

In FIG. 3a to 3d show known corner blade shapes;

In FIG. 4a shows a side view of a known milling tool without chip forming grooves;

In FIG. 4b shows a side view of a known milling tool which comprises chip grooves;

In FIG. 5 shows a schematic view of a tool according to a technical solution;

In FIG. 6 shows an embodiment of a milling tool according to the invention adapted to produce a chamfered corner;

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elaborated documents, reaction to the Office assessment from 25.01.2011

In FIG. 7 shows an embodiment of a milling tool according to the invention adapted to produce a rounded corner;

In FIG. 8 shows the geometry of the material removal process for the milling tool of FIG. 6; and

In FIG. 9 shows the geometry of the material removal process for the milling tool of FIG. 7th

Examples of technical solution

In FIG. 1 to 4 show geometrical arrangements of various milling tools known in the art, which are described in detail above in the section which describes the prior art for a milling tool according to the invention.

In FIG. 5 is a schematic view of a shank type milling cutter according to the present invention showing the configuration of the peripheral cutting edges 1, the front cutting edges 2, the corner cutting edges 3 and the chip forming groove 7.

The area of the tool S in which the greatest stresses occur is the corner cutting edge 3.

In FIG. 6 shows the geometry of a corner cutting edge 3 machining a bevelled corner, wherein the corner cutting edge 3 is comprised of a first cutting edge, a rectangular triangle 9, 10, and a contiguous curved cutting edge having a radius R.

Therefore, the corner can be formed in a substantially single step.

In FIG. 7 shows another embodiment of a milling tool according to the invention usable for machining rounded corner portions. In this case, the first part of the corner cutting edge 3 of the tool consists of a hypotenuse part 11 which connects the leggings 12,13 of a rectangular triangle having an angle α, and a contiguous curved part having a radius R.

An essential feature of the invention is that chip formation on the corner blades 3 of the tool S is achieved by configuring adjacent corner blades 3 so that they have different geometric shapes.

’’ Redesigned, response to the Office’s assessment of 25.01.2011

In FIG. 8 shows cross-sectional shapes of a chip separated by a milling tool having on different cutting edges different geometries of corner cutting edges 3, as shown in FIG. 6. The cross-sections are shown as a function of the chip thickness H of FIG. 1 to 4, since the cutting edge having the bevelled corner cutting geometry continues on a portion of the cutting surface having the rounding corner cutting geometry.

In FIG. 9 shows the cross-sectional shapes of a chip separated by a milling tool having, on adjacent blades, different geometries of the corner blades 3, as shown in FIG. 7. The cross-sections are shown as a function of the chip thickness H of FIG. 1 to 4, since the blade having the geometry of the rounded corner blade continues on the part of the area machined by the blade having the geometry of the bevelled corner blade.

The corner cutting edges 3 of the milling tool according to the invention may have geometrical arrangements different from the geometry described above, provided that the adjacent cutting edges have different corner cutting geometries, for example rounded and multiple chamfered. The tapered portions may have the shapes described by parabolic or any other function.

Using corner blades with other geometrical shapes, plane milling can be performed which provides a high quality machined surface that does not require finishing.

Claims (4)

PROTECTION REQUIREMENTS A milling tool having a tool body, a shank portion (5) and blades (1, 2, 3) adapted to machine a workpiece (M), wherein the blades (1, 2, 3) are located on the tool body or 5 cutting inserts fixed to the tool body, characterized in that the corner blades (3) of the tool (S) formed on the joints of the peripheral blades (1) and the front blades (2) are arranged such that the corner blades (3) adjacent blades have different geometric shapes. A milling tool according to claim 1, characterized in that it has a shank type or disk type configuration. A milling tool according to claim 1 or 2, characterized in that it has cutting inserts wherein the corner cutting edge of each cutting insert is formed by successive sections of different geometric shape. A milling tool according to any one of claims 1 to 3, characterized in that it has a geometrical arrangement in which the tool has an even number of blades, the odd blades having a rounded shape and the even blades having a chamfered shape. A milling tool according to any one of claims 1 to 3, characterized in that the tool (S) has a geometrical arrangement in which the cutting radii R are between 0.5 to 5 mm and the cutting angles and bevels are between 15 to 75 °.