JP2001212711A - Formed milling cutter for rough cutting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a formed milling cutter for roughing capable of increasing working efficiency and facilitating regrinding in a formed milling cutter used for roughing a formed milling cutter having a varying form radius. SOLUTION: In this formed milling cutter for rough cutting having a rotating locus forming a shape similar to the form thereof by differentiating the phase of an outer periphery cutting blade having a waveform by a first blade and a second blade, the flank of the outer periphery cutting blade is formed by providing a distance between the rotating locus of the cutting blade and a flank (hereafter referred to as waste percentage of flank) at the positions where the rotating angle from the cutting blade about a rotating axis are equal to each other at roughly any position along the cutting blade.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention is based on the JIS standard (JIS
B0172, terminology of milling), a tool for rough machining of a general-purpose milling cutter used for groove machining of a turbine blade or a turbine disk.

[0002]

2. Description of the Related Art A general shape milling machine is a milling machine for forming a foam having a special contour, and has a name according to an application such as a groove for a turbine blade or a turbine disk. It is used in the form of a second milling cutter or a contour milling cutter provided with a blade along the form. Therefore, the form milling machine has a feature that the original form can be easily regenerated by re-grinding even if the milling cutter is used for a long time and is worn. In the case of having a complex form including a curve with a changing curvature, the thickness of the chip changes greatly at each part of the form, and the cutability is not uniform. There was a problem with large rough cutting. As an improvement of this, for example, there is an example of a corrugated roughing cutting edge disclosed in JP-A-11-267916.

[0003] In particular, in the form milling machine used for groove machining,
The shaving amount is large and the form is finished from a solid state. For example, as described in Japanese Unexamined Patent Application Publication No. 11-267916, FIG. 8, machining is performed through a process such as roughing, special shape, and finishing using a plurality of tools. When a large number of tools are used in this way, not only the number of tools but also the processing time is required, resulting in poor efficiency.

[0004]

SUMMARY OF THE INVENTION Problems to be Solved by the Invention
The corrugated roughing cutting edge of No. 916 is the blade shape used in FIG. 10 (d), and the clearance angle of the outer peripheral cutting edge is substantially the same size. This is a problem because the blade shape is greatly different, and there is a problem that it is difficult to maintain the foam during repolishing.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and has an outer peripheral cutting edge shape and an arrangement thereof in a general milling cutter used for rough machining of a general milling cutter in which the curvature of a foam changes. By reducing the cutting force, it is possible to increase the feed rate by reducing the cutting force even for a complicated form, improve the machining efficiency and facilitate re-grinding. The purpose is to provide.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention forms a form including a curve whose curvature varies, such as a form milling cutter used for machining a turbine blade or a turbine disk. In the form milling machine having a plurality of cutting edges, the outer circumferential cutting edge having a corrugated shape is different in phase between one blade and the next blade, and the rotation locus is a general form milling forming an approximate shape of a foam, The flank of the outer peripheral cutting edge is characterized in that an interval between the flank of the cutting edge rotation path and the flank at a position where the rotation angle from the cutting edge is equal to the rotation axis is substantially equal at an arbitrary position along the cutting edge. This is a general-purpose milling cutter for roughing.

[Action]

[0007] By applying the present invention, even if the length of the cutting edge is long due to the corrugated cutting edge, the chip can be made finer, the cutting resistance can be reduced, the chip can be easily discharged, and the wear of the cutting edge is localized to the local area. It is possible to increase the cutting conditions without causing any cuts, burrs and the like caused by the wavy cutting edges on the formed foam, and to obtain a smooth processed surface. Normally, the corrugated cutting edge is cut vertically into the cutting edge. However, if the form is complicated as in the present invention, the corrugated cutting edge may be provided on an inclined surface. A part of the corrugated cutting edge acts as a cutting edge in the rotation direction of the tool. for that reason,
Although a failure is likely to occur in this part, it can be improved by applying the present invention. The corrugated cutting edge may be provided alternately with one blade and the next blade, but three or more blades may be provided at different positions.

[0008] The corrugated cutting edge is formed in a continuous wave shape of a substantially circular arc of a convex and a substantially circular arc of a concave shape. The reason for setting it to be 0.8 times is that if it is less than 0.01 times, chips cannot be sufficiently divided, and if it exceeds 0.8 times, it becomes difficult to connect the chips smoothly. The distance from the cutting edge was set to 0.01 to 0.5 times. The reason why the radius of the convex arc connected to the cutting edge is set to 0.2 to 5 times the interval is that if the radius is less than 0.2, the arc is too small to be provided, and there is no point in providing the arc. If provided, the cutting edge would be too long, so the radius of the convex substantially circular arc connected to the cutting edge was 0.2 to 5 times the interval. By setting these numerical values, it is possible to reduce the interval between the waveform cutting edges and to obtain a roughing blade in which the waveform cutting edge of one blade and the waveform cutting edge of the next blade are shifted in position and overlapped. Even if the contour of the cutting edge may deviate from the overall form due to the blade, the depth of the corrugated cutting edge may be shallow within the above-mentioned range. it can.

Next, since the form of the cutting edge of the form milling machine is various, the mode thereof will be described. First, when the form of the cutting edge is at a small angle with respect to a plane orthogonal to the rotation axis of the milling cutter, the slope of the cutting edge acts so as to cut, the chip thickness becomes thin, and the scraping phenomenon occurs. In addition, since the direction in which the waveform cutting edge is cut does not match the cutting direction, the effect is diminished and the cutting resistance increases. Therefore, when the form of the cutting edge is inclined at an angle of 30 ° or less, a straight line portion inclined at an angle smaller than the angle is provided between the substantially circular arc and the substantially circular arc so that the apex of the convex portion of the corrugated cutting edge is provided. The effect of the original waveform cutting edge can be obtained by increasing the interval.

Next, when the curvature of the form of the cutting edge is large, particularly when the adjacent cutting edge is curved by 60 degrees or more, one of the two cutting edges is located on the above-mentioned inclined surface. In addition, since the curved portion is short, the cutting edge is offset by one portion and moved in and out with one blade and the next blade. That is, the effect of the corrugated cutting edge is obtained to enhance the machinability.

Further, in the present invention, a part of the form of the cutting edge is thinned alternately for each cutting edge. In particular, when the inclined surface is at a steep angle, since the rubbing phenomenon is large on the side surface, it can be alleviated by thinning a part of the cutting edge. If the diameter difference between the cutting blades is large depending on the position of the form, the interval between the first blade and the next blade is reduced in the small diameter portion, and the sharpness is reduced. Further, even at the outer peripheral portion, it may be thinned out due to the twist angle or the form.

Further, when a coating is applied to the form milling cutter, the coating may be made of a transition metal of Group 4a, 5a or 6a of the periodic table, a low melting point metal, a rare earth metal, or a carbide of Al, nitride, or the like. , Oxides, borides, hard boron nitride, hard carbon, and one or more hard films selected from the group consisting of solid solutions and mixtures thereof and / or M
One or two or more lubricating films such as oS may be 0.2
When coated with a thickness of up to 20 μ, the wear resistance can be improved and the service life can be further extended. In addition, a high-speed steel, an ultra-fine-grain cemented carbide, a TiCN-based cermet, or the like can be used for the form milling machine. In particular, a molten high-speed steel and a powdered high-speed steel are excellent in terms of workability.

Further, by making the amount of flank drop substantially equal in each part of the foam, a re-polishing method similar to that of a full-form milling machine for finishing or the like can be performed. Maintenance of the processed form by polishing and re-polishing itself become easy. Hereinafter, the present invention will be described with reference to the drawings showing the embodiments.

【Example】

FIGS. 1 and 2 show an embodiment of the present invention, which is a general-purpose milling cutter used for roughing a blade root portion of a turbine blade having a Christmas tree form. The form milling cutter shown in FIG. 1 is a second-order cutting form milling cutter in which the outer peripheral cutting edge and the following outer peripheral flank are corrugated. As shown in an enlarged view in FIG. 3, it is composed of a convex arc portion constituting the outermost peripheral portion, a steep slope connected thereto, and a concave arc portion constituting a small diameter portion. The corrugated cutting edges are provided at intervals of 0.2 mm in depth and 1 to 1.5 mm in width along the cutting edges. Here, the details of the corrugated cutting edge are as shown in FIGS.
That is, FIG. 4 shows a wave-shaped cutting edge having a continuous wave shape of a substantially circular arc and a substantially circular arc provided at the outermost convex circular arc portion, and FIG. A small angle linear portion is provided. FIG. 6 shows a bent portion that transitions from the outermost periphery to a steep slope portion. Since the curvature is large, the cutting edge is moved in and out to replace the corrugated cutting edge. The amount of fall of the outer peripheral flank is constant at each part of the Christmas tree-shaped form. Furthermore, since the amount of flank drop is constant at each part of the foam, not only the cutting conditions can be increased but also maintained after repolishing, and further, there is no change in the foam after repolishing, and the regrinding itself is also scooped. Because it can be performed from the surface side, it became easy.

Using this, a flat plate of stainless steel SUS410 was formed and cut into the above-mentioned form. The cutting specifications are a cut of 15 mm in the axial direction of the tool, a cut of 10 mm in the radial direction of the tool, a rotational speed of the tool of 65 revolutions / min, and a feed speed of 65 mm / min. In the example of the present invention, one workpiece was completed in 40 minutes. For comparison, when the cutter described in the prior art for processing the same form was used, the number of rotations could not be increased, so that two cutters per workpiece were used.
It took 50 minutes.

[0016]

As described above, according to the present invention, even a complicated form such as a Christmas tree type milling cutter has a good chip discharge property and can be processed at high speed.
Furthermore, maintenance of the processed foam by re-polishing and re-polishing itself became easy.

[Brief description of the drawings]

FIG. 1 shows a front view of an embodiment of the present invention.

FIG. 2 shows a part of the forming form formed according to FIG.

FIG. 3 shows the configuration of another part of the corrugated cutting edge of FIG. 1;

FIG. 4 shows the configuration of still another part of the corrugated cutting edge of FIG. 1;

FIG. 5 shows a configuration of still another part of the corrugated cutting edge of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body 2 Cutting edge 3 Corrugated cutting edge 4 Depth of corrugated cutting edge 5 Spacing of corrugated cutting edge 6 Roundness connecting cutting edge with cutting edge 7 Form of total form α Angle of inclination of form of general form θ Angle of inclination of the substantially straight part provided on the waveform cutting edge

Claims (4)

[Claims] 1. A general-purpose milling cutter having a plurality of cutting edges forming a form including a curve whose curvature changes, such as a general-purpose milling cutter used for machining a groove of a turbine blade or a turbine disk, has a corrugated shape. A form milling machine in which the outer peripheral cutting edge has a different phase between the first blade and the next blade, and the rotation trajectory forms an approximate shape of a foam. 1. A rough milling cutter according to claim 1, wherein the clearance between the cutting edge rotation track and the flank at a position where the rotation angle is equal is substantially equal at an arbitrary position along the cutting edge. 2. A rough milling cutter according to claim 1, wherein said corrugated cutting edge has a continuous wave shape of a substantially circular arc of a convex and a substantially circular arc of a concave, and the difference between the concavities and convexities of said corrugated cutting edge is an adjacent wave. The radius of the convex substantially circular arc connected to the cutting edge is set to a value of 0.2 to 5 times the interval between the apex of the cutting edge convex portion and / or 0.2 to 5 times the interval. Form milling for roughing. 3. The milling cutter according to claim 1, wherein the form of the cutting edge is inclined at an angle of not more than 30 degrees with respect to a plane perpendicular to the axis of rotation of the milling machine. A general form milling machine for rough machining, wherein a straight line portion inclined at an angle smaller than the angle is provided between a substantially circular arc and a substantially circular arc. 4. A rough milling cutter according to claim 1, wherein the form of the cutting edge has a large curvature, and when the adjacent cutting edge is curved by more than 60 degrees.
A general-purpose milling cutter for roughing, characterized in that the cutting edge form is moved in and out of the first and second blades.