JPH06281B2 - Step cutting milling cutter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a step of a milling cutter such as an end mill, a flat milling cutter, and a side milling cutter mainly for cutting a flat surface by an outer peripheral cutting edge, which is configured to enable high efficiency heavy cutting. The present invention relates to a cutting type milling cutter.

In the conventional step type cutter, the positions of the cutting edges arranged on the outer peripheral surface of the cutter are sequentially shifted in steps in the direction of the central axis of rotation of the cutter and in the radial direction. When comparing such a step type cutter with a non-step type ordinary cutter (for example, an end mill), in the case of an ordinary cutter, the cutting shape shown in FIG.
If the axial cutting auxiliary is d and the feed amount per one rotation of the blade is f, chips having a width d and a thickness f are generated. On the other hand, in the case of a step type cutter, as shown in Fig. 2, f'is the feed amount per rotation or an integer fraction thereof, and is divided into d / the number of blades or an integer fraction of the number of blades. Generated chips.

As described above, the step type cutter has a small chip width (1) when the machining feed amount is constant. (2) f'is the feed amount per revolution (or 1 / integral thereof), and since it is the feed per blade, the chip thickness becomes thick and the specific cutting resistance is small. (3) Chip pockets may be small, as wide chips do not come out. (4) Since the number of cutting edges that participate in chips at the same time is less than half of the total number of cutting edges, the total cutting width is d / 2.
The cutting width of each cutting edge is narrow and the chip thickness is large, resulting in good sharpness. There are advantages such as.

However, conventionally known step-type cutters have cutting edges arranged in steps in both the rotational center axis direction and the radial direction of the cutter, so that flat milling cutters, end mills, side milling machines, etc. In the cutter which produces the final finishing plane (or curved surface) by the above, the finishing surface has a step-like shape by the axial step amount Sa and the radial step amount Sr of each cutting edge as shown in FIG. However, there is a drawback in that it is impossible to generate a flat surface (or curved surface) by the outer peripheral cutting edge, which is the basic performance of.

An object of the present invention is to provide a milling cutter capable of performing heavy-duty step-cutting heavy-duty cutting, such as a flat milling cutter, a side milling cutter, and an end mill, which performs flat surface machining mainly by an outer peripheral cutting edge.

The present invention, in the conventional step-type cutter, the cutting edge is arranged by displacing only the axial direction, and instead of being not displaced in the radial direction, the outer peripheral cutting edge has a plurality of linear main cutting edges and auxiliary cutting edges that are continuous. The cutting width is narrow because the protruding point apex in the cutting order is offset from the protruding point apex in the front cutting order in the direction of the auxiliary cutting edge in the axial direction. Taking advantage of the feature of a step type cutter that discharges chips with a large chip thickness, it is characterized in that it is possible to prevent the disadvantage that the processed surface by the outer peripheral cutting edge becomes stepwise.

Hereinafter, the present invention will be described with reference to the drawings.

FIGS. 4 and 5 show an embodiment in which the present invention is applied to a throw-away end mill, in which eight throw-away tips 2 _a , 2 _b, ... Are provided on the outer peripheral portion of the cutter body 1. It shows a state in which 2 _g and 2 _h are attached.
Each throw-away tip 2 _a , 2 _b, ... 2 _g , 2 _h is attached with its rotation direction shifted by a certain angle β, and has the same radius of rotation, but is attached with _a certain amount Sa in the axial direction and rotated. The radii are the same for all, and the main cutting edge 3 is attached so as to be inclined with respect to the outer peripheral surface 4 of each blade by an inclination angle α. When the main cutting edge is extended and considered, it becomes a continuous saw-tooth shape, and since this extended portion does not participate in actual cutting, the effect of the present invention is not affected even with such a configuration. Regarding the direction of rotation, the protrusion apex formed by the main cutting edge 3 and the sub cutting edge of each throw-away tip is such that the projection apex at the rear of the cutting order is in the sub cutting edge direction with respect to the protrusion apex at the front of the cutting order. It is attached with _a certain amount of Sa offset. In addition,
Here, the inclination angle α of the main cutting edge 3 with respect to the outer peripheral surface 4 is such that the feed amount per revolution of the cutter is f ′, the circumferential pitch angle of the cutting edge is β, and the axial step amount is Sa. If
It must be determined so as to satisfy α ≧ tan ⁻¹ {(f ′ / S _a ) × (β / 360)}, and the axial step amount _a
Also, according to the present invention, even if the pitch angle β in the circumferential direction of the cutting edge is changed for each cutting edge and the cutting edge is unequal division, the protrusion tip of the main cutting edge 3 of the throw-away tip has a rearward cutting order. Is arranged in the sub-cutting edge direction of the cutting order preceding item, and the main cutting edge 3 is inclined by an angle α with respect to the outer peripheral surface. Therefore, the main cutting edge 3 is in all throw-away tips, Only the amount of deviation S _{a in} the axial direction is involved in cutting. Therefore, chips with a narrow width and a large thickness are discharged. In this way, for example, when the end mill is of the throw away type, the cutting width for cutting with each throw away tip is less than 1/2 of the cutting edge length, and like the face milling, the feed per revolution It enables heavy-duty heavy-duty cutting.

6 to 8 show another embodiment when applied to a flat brazing mill. Each cutting edge 5 _a , 5 _b
...... 5 _k and 5 _l are saw-tooth-shaped as shown in FIG. 8 and are displaced by _a constant amount Sa in the axial direction. Here, the saw-tooth-shaped inclination angle α of each cutting edge with respect to the outer peripheral surface 4 is determined in the same manner as in the above-described throw-away end mill, and the axial step amount S _a and the circumferential pitch angle β are unequal. It may be divided.

In the case of such a brazing (or solid) type cutter, there is an effect that it can be manufactured relatively inexpensively.

It should be noted that the main cutting edge may be arranged by twisting in a spiral.

When cutting with the step cutting type milling cutter configured as described above, if the step amount in the axial direction is S _a and the feed amount per revolution of the cutter is f ′, the conventional steps described in FIG. 9th as well as the type cutter
As shown in the figure, a narrow chip with _a width S _a and a thickness f ′ is ejected, and the finished surface by the outer peripheral cutting edge of this step cutting type milling cutter is the finished surface of the step type cutter. Has a stepped shape as described with reference to FIG. 3, whereas it has a planar shape as shown in FIG.

11 to 13 show another embodiment in which the present invention is applied to a throw-away end mill, and FIG. 11 shows a throw-away tip 11 mounted on this end mill. The throw-away tip 11 is an equilateral triangle whose basic shape has a constant thickness t, and has a mounting hole 12 in the center. The cutting edge 13 is provided on the outer periphery of the equilateral triangle, and the length l thereof is equal to or slightly longer than the axial step amount S _a (see FIG. 12) of the end mill, and a portion other than the cutting edge 13 on each side of the triangle. Escape 14 and cutting edge
It escapes from 13 toward the center of the equilateral triangle.

FIG. 12 and FIG. 13 show a step cutting type throw-away end mill equipped with the throwaway tip 11 having the special shape. The eight throw-away tips 11 _a , which are provided on the outer peripheral portion of the cutter body 15, are shown in FIG. 11 _b …… 11
_It shows the state with _g and 11 _h attached. The throw-away tips 11 _a , 11 _b, ..., 11 _g , 11 _h are mounted with a certain angle β offset in the rotational direction, and the radius of gyration is the same, but they are displaced by _a certain amount Sa in the axial direction. There is. The cutting edge 13 is installed parallel to the outer peripheral surface. Here, the escape amount δ of the throw-away tip has a relationship of δ ≧ f ′ × β / 360, where f ′ is the feed amount per rotation of this cutter and β is the circumferential pitch angle of the cutting edge. However, the axial step amount S _a and the circumferential pitch angle β of the cutting edge may be changed for each cutting edge and may be unequal division.

When the throw-away method is used in this way, the cutting width for cutting with each throw-away tip is 1/2 or less of the length of one side of the throw-away tip, and the feed amount per rotation is the same as for cutting with a face milling cutter. Enables large heavy cutting.

14 to 16 show still another embodiment when applied to a brazing flat milling machine. 12 pieces of cutting edge _{16 a, 16 b ...... 16 k} , 16 l , as shown in FIG. 16, then when the cutting edge (e.g. 16 _a cutting 16 _b, 16 _b
In the case of 16 _c ), the amount of axial step is equal to or slightly longer than the axial step amount S _a, and the other portions are left as shown in FIGS.
It is released as described in the embodiment of the step cutting type throw-away end mill in FIG. Here, the escape amount δ may satisfy the same condition as in the case of the throw-away end mill, and the axial step amount S _a and the circumferential pitch angle β may be unequally divided.

In the case of such a brazing (or solid) type cutter, there is an effect that it can be manufactured relatively inexpensively.

When cutting with the step cutting type milling cutter configured as shown in FIGS. 11 to 16, the axial step amount is S _a , and the feed amount per one rotation of the cutter is
If f ′, as in the step cutting type milling cutter described in FIG. 9, as shown in FIG. 17, the width S _a and the thickness are
Chips with a narrow f'width and a large thickness are discharged, and the machined surface in this case becomes a perfect plane, which is applicable to finishing.

〔The invention's effect〕

As described above, according to the present invention, a plurality of grooves are provided with a main cutting edge and a sub cutting edge that are formed in a saw-tooth shape, and a protrusion of a saw blade portion formed by each of the main cutting edge and the sub cutting edge. The main cutting edge of the cutting blade order rear position is arranged in a step by shifting in the sub cutting edge direction of the main cutting edge of the cutting order front position, and the spacing of the main cutting edge and the sawtooth-shaped protruding portion. By forming the amount of deviation almost the same, the step type cutter prevents the processing surface from becoming microscopically stepwise and macroscopically sloping, and the movement trajectory of the center of the cutter Since it is possible to form a cutting surface parallel to the cutting edge and to reduce the cutting width of each cutting edge, it is possible to reduce the cutting resistance. Further, since the auxiliary cutting edge can be formed to have an obtuse angle with respect to the main cutting edge, the edge strength is increased and powerful heavy cutting is possible.

[Brief description of drawings]

FIG. 1 is a sectional view of a cutting shape by a normal cutter, and FIG.
The figure is a cross-sectional view of the cutting shape with a step cutter, the third
FIG. 4 is a perspective view of a finishing surface by an outer peripheral cutting edge of a step type cutter, FIG. 4 is a front view when the present invention is applied to a throw-away end mill, FIG. 5 is a side view thereof, and FIG. FIG. 7 is a front view of a brazing flat milling cutter as another embodiment, FIG. 7 is a side view thereof, FIG. 8 is a detailed view of the outer peripheral cutting edge thereof, and FIG. 9 is a step cutting type milling cutter of FIGS. A cross-sectional view of the cutting shape, FIG. 10 is a perspective view of a finish surface similarly processed by the outer peripheral cutting edge, and FIG. 11 shows another embodiment of a throw-away tip used when the present invention is applied to a throw-away end mill. Fig. 12 is a perspective view, Fig. 12 is a front view of a throw-away end mill using the throw-away tip of Fig. 11, Fig. 13 is a side view thereof, and Fig. 14 is a brazing flat milling machine which is still another embodiment of the present invention. Front view of Figure 15 is a side view, FIG. 16 detailed view of the peripheral cutting edge, FIG. 17 is a sectional view of a cutting shape by step cutting type milling cutter of the 12-16 diagrams. 1 ... Cutter body, 2 ... Throw-away tip,
3 …… Main cutting edge, 4 …… Cutter outer surface, 5 …… Brazed main cutting edge, 11 …… Throw-away tip, 12 ……
Mounting holes, 13 ... Cutting edge, 14 ... Relief, 15 ... Cutter body, 16 ... Brazing flat milling cutting edge, α ... Inclination angle of outer peripheral cutting edge with respect to outer peripheral surface, β ... Each Circumferential pitch angle of cutting edge, S _a …… Axial step amount of each cutting edge, δ …… Relief amount, f, f ′ …… Feed amount per 1 rotation of blade

Claims (7)

[Claims] 1. A saw blade of each cutting edge, wherein a plurality of grooves are provided in the outer peripheral surface of the cutter body in the axial direction, and a linear main cutting edge and a sub cutting edge are formed in a sawtooth shape in each groove. The protrusion apex of the cutting order rear position in the protruding portion of the part is arranged in a stepwise manner in the axial direction with respect to the protrusion apex of the cutting order front position and is displaced in the direction of the sub-cutting edge thereof, and the main cutting edge A step cutting type milling cutter characterized in that the gap and the amount of displacement of the saw-toothed protrusion are formed to be substantially the same. 2. The step cutting type milling cutter according to claim 1, wherein the main cutting edge and the sub cutting edge are integrally formed into a saw-tooth shape. 3. A step cutting type milling cutter according to claim 1, wherein the main cutting edge and the sub cutting edge which are integrally formed in the shape of a saw blade are attached to a cutter body. 4. One of the above-mentioned blade-shaped main cutting edge and sub-cutting edge.
The step cutting type milling cutter according to claim 1, wherein a plurality of throwaway tips constituting one of the two are mounted in the axial direction of the same groove. 5. A plurality of throw-away tips each having a plurality of main cutting edges and sub-cutting edges formed in the shape of a saw blade are mounted in the axial direction of the same groove. Step cutting type milling cutter. 6. The invention as set forth in claim 1, wherein the groove formed in the axial direction on the outer peripheral surface of the cutter body has a spiral shape. Step cutting type milling cutter. 7. The invention according to claim 1, wherein the grooves provided in the axial direction on the outer peripheral surface of the cutter body have unequal division pitches. A step cutting type milling cutter according to item 5 or 6.