JP3354905B2 - Form milling for rough cutting - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a form milling machine used for rough cutting of a form including a curve having a changing curvature in a machine tool.

[0002]

2. Description of the Related Art Form milling machines conform to JIS (JIS) standards.
B0172, milling terminology)
This is a milling cutter for forming a foam with a special contour, and is called a milling cutter used for forming grooves in a turbine blade or a turbine disk. Conventional cutters and roughing end mills with a corrugated cutting edge, whose purpose is to create a constant curvature or a straight plane, do not fall under the general form of milling cutters using only these blade shapes. The form milling cutter is used in the form of a second-order milling cutter in which a flank is formed by a second-order cutting process or a contour milling cutter provided with a blade along a form. Therefore, the form milling machine has the feature that the original form can be easily regenerated by re-grinding even if it is used for a long time and wears out, but on the other hand, depending on the form, the chip width becomes long and cutting Impair the nature. In particular, in the case of having a complex form including a curve in which the curvature changes, the change in the chip thickness at each part of the form is large, the cutting property is not uniform, and the chip is jammed or jammed.
There was a problem in rough cutting with a large depth of cut. As an improvement measure for cutting chips and facilitating chip discharge, for example, as shown in Japanese Patent Application Laid-Open No. 8-39323, a V-shaped or U-shaped nick-shaped cutting edge may be provided on a cutting edge. Also, as shown in FIGS. 1 and 2, a nick is provided in a part of the foam to improve the machinability.

[0003]

However, the conventional nicked general-purpose milling cutter described in the prior art focuses on the cutting of chips, so that the nick-to-nick spacing is wider than the cutting edge length, and cutting is performed. There was no effect of improving the resistance, and therefore it could not be expected to improve the cutting efficiency by increasing the cutting conditions for rough cutting. V-shaped, U
Inadvertently providing a character nick may cause wear to concentrate at the intersection of the cutting edge and the nick, impairing the cutting accuracy, shortening the tool life, and there is a problem with rough milling, even if it is used in a general milling machine. This is a problem particularly in the case of a form having a large curvature, a form inclined at a large angle with respect to the rotation axis of the milling machine, and the like.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and by improving the shape and arrangement of nicks of a general-purpose milling cutter, it is possible to improve the quality of a complicated form. An object of the present invention is to provide a form milling machine for rough cutting, which has improved chipping efficiency and can improve the machining efficiency capable of increasing the feed rate by reducing the cutting resistance.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention achieves the above-mentioned object by providing a forma containing a curve having a varying curvature.
In a milling cutter having a plurality of cutting edges comprising a plurality of cutting edges, the cutting edges are provided with corrugated cutting edges at different positions for one and the next blades, and the corrugated cutting edges are formed of a continuous substantially arcuate and concave substantially arcuate shape. The main cutting edge and its side face are smoothly connected.

[0006]

By applying the present invention, the chips can be made finer and easier to discharge even when the length of the cutting edge is long due to the corrugated cutting edge. Since the blade and the blade are smoothly connected to each other smoothly, the cutting edge is not worn locally, and the cutting conditions can be increased. In addition, the cut edge caused by the corrugated cutting edge on the formed form can be obtained. No burrs, etc.
A smooth processed surface can be obtained.

Conventionally, the nick is normally cut vertically into the cutting edge. However, if the form is complicated as in the present invention, a nick may be provided on the inclined surface. A part of the nick acts as a cutting edge in the rotation direction of the tool. Therefore, a failure is likely to occur in this portion, but 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 convex arc and a substantially concave circular arc, and the difference between the concave and convex portions of the corrugated cutting edge is 0.01 times to 0 times the interval between the adjacent peaks of the corrugated cutting edge. The reason for setting it to be 0.8 times is that if it is less than 0.01 times, the 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 interval is less than 0.2, the arc is too small to be provided and there is no point in providing a large value exceeding 5 times. 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. Also in the case of the V-shaped and U-shaped cutting edges, similar operations and effects can be obtained by smoothly connecting the main cutting edges with a large circular arc as in the case of the wavy cutting edges.

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 at 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, nitride, or oxide of Al. , Boride, hard boron nitride, hard carbon, and one or more hard films selected from the group consisting of solid solutions and mixtures thereof and / or one lubricating film such as MoS Alternatively, coating with a multilayer of two or more layers at a thickness of 0.2 to 20 μ can improve abrasion resistance and further prolong the life. 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. Hereinafter, the present invention will be described with reference to the drawings showing the embodiments.

[0012]

FIG. 3 shows a milling cutter having a maximum diameter of 118 mm, a cutting edge width of 20 mm, and eight blades. As shown in an enlarged view in FIG. 4, the overall form is composed of a convex arc portion forming the outermost peripheral portion, a steep slope connected thereto, and a concave arc portion forming 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 waveform cutting edge 5, is shown in Figure 6. That is, FIG. 5 shows a wave-shaped cutting edge in the form of a continuous wavy shape of a convex substantially circular arc and a concave substantially circular arc provided on the outermost convex circular arc portion, and FIG. A small angle linear portion is provided.

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 45 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.

FIG. 7 shows another embodiment of the present invention, in which the dimensions are similar to those of FIG. 1 described above, but instead of the second cutting edge type, the flank is formed as a contoured edge shape. A cutting edge is provided toward the axis. The side blades are thinned out from the vicinity of the outer periphery for each blade. Since the distance between the cutting edges becomes narrower as approaching the partial axis, cutting performance can be enhanced by thinning.

[0015]

As described above, according to the present invention, by improving the shape and arrangement of the corrugated cutting edge, it is possible to obtain a good chip discharge property, and to reduce the cutting resistance to increase the feed rate. The result is an improved form milling cutter for rough cutting.

[Brief description of the drawings]

FIG. 1 shows a front view of an example of a conventional product.

FIG. 2 shows a side view of FIG. 1;

FIG. 3 shows a front view of another embodiment of the present invention.

FIG. 4 shows a full-form form formed according to FIG.

FIG. 5 shows a configuration of a corrugated cutting edge of a part of FIG. 3;

FIG. 6 shows the configuration of another part of the corrugated cutting edge of FIG. 3;

Figure 7 shows a front view of another embodiment of the present invention.

Figure 8 shows a front view of another embodiment of the present invention.

Claims (4)

(57) [Claims] 1. A form milling machine having a plurality of cutting edges forming a form including a curve of varying curvature.
The cutting edge is provided with a corrugated cutting edge at a different position between the first blade and the next blade, and the corrugated cutting edge is formed by a continuous waveform of a substantially circular convex and a substantially circular concave. fries. 2. The rough milling cutter according to claim 1, wherein the difference between the irregularities of the corrugated cutting edge is 0.01 to 0.8 times the interval between adjacent corrugated cutting edge convex portions, and / or Alternatively, the radius of the convex substantially circular arc connected to the cutting edge is 0.2 to 5 times the interval.
Form milling cutter for rough cutting characterized by being provided with double the value. 3. A rough 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 cutter. A general form milling cutter for rough cutting, 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 form-milling of claims 1 to 3, wherein the cutting edge follower - form-milling for rough cutting, characterized in that thinned out alternately for each cutting edge part of the arm.