JP3237035B2 - Indexable inserts and indexable milling tools - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw-away insert used as a cutting tool such as a face mill or a cutter, and more particularly to a throw-away insert for cutting a work material into a right-angled surface. About.

[0002]

2. Description of the Related Art
When the indexable insert is attached to a milling cutter, a cutter or the like, in order to improve the cutting performance, the insert is inclined so as to increase the positive axial rake angle. For example, as shown in FIG. 6A, a plate-like throw-away tip 1 having a substantially triangular shape in plan view is
(B), the indexable insert 1 is attached such that the rake face is inclined with respect to the axis L of the milling cutter 2. As shown in FIG. In this case, since the main cutting edge 3 of the throw-away tip 1 is formed in a straight line, the turning radius at the central portion of the main cutting edge becomes smaller than the turning radius at the cutting edge tip 3a and the cutting edge rear end 3b. I will. Therefore, as shown in FIG. 6 (a), even if the work material 4 is to be cut into a right-angled surface, the processed surface 5 is cut into a convex curved surface shape protruding at the central portion with respect to the processed bottom surface 6. The processing accuracy was low.

[0003] In view of the above problems, it is an object of the present invention to provide a throw-away insert which is capable of improving the processing accuracy while maintaining a high mounting accuracy of the insert.

[0004]

The indexable insert according to the present invention has a main cutting edge formed on each side of a peripheral edge of an upper surface opposed to a lower surface forming a seating surface, and a sub cutting edge formed on a nose portion. In addition, in a substantially flat-shaped throw-away chip in which a breaker groove is formed on the rake face of the upper surface, the main cutting edge is formed in a convex curved shape in a plan view, and each side surface between the upper and lower surfaces is provided with the main cutting edge. A convex curved side upper surface and a planar lower surface side forming a flank of the cutting edge are formed, and the breaker groove has a maximum breaker width at a central portion of the main cutting edge and approaches the nose portion. before the low-cut side region with a planar view substantially circular arc shape gradually decreases
Breaker width once increases toward the nose and gradually decreases
A small groove having a substantially small arc shape in a plan view is formed,
The sub-portion is adjacent to the sub-portion so as to be partitioned into small grooves.
Sub cutting edge extending from the ridge line of the cutting edge toward the center of the upper surface
It is characterized in that flat projections of the same height are formed
Is what you do.

[0005] Further , on the upper surface, the pressing surface for fixing the throw-away tip is characterized by forming a plane parallel to the lower surface which is partitioned by a breaker groove and extends in the direction of each nose.

Also, a throw-away type milling machine according to the present invention.
The tool is located on the outer periphery of the tip of the milling tool body that rotates around the axis,
The indexable insert has its main cutting edge outside the tool body.
Position on the peripheral side, and the sub-cutting edge on the tip side.
With an axial rake angle and mounted in an inclined state
Indexable milling tool, the main cutting edge of which is
It is located on an arc plane centered on the axis of the milling tool body.
The main surface of the cutting edge is
It is characterized in that it is cut at a right angle to it.

[0007]

When the indexable insert is fixed to the mounting seat of the cutting tool, the side surface in contact with the seating surface of the indexable insert is formed as a flat surface, so that its positioning is easy, and it is difficult to move. By deep cutting
In the case of cutting, the chips generated by the main cutting edge
Flows smoothly and curls in the largest central area,
Chips are easily ejected without clogging
Cutting resistance is reduced. In addition, cutting of work material with low depth of cut
Chips are curled by short runs in small grooves.
And are easily discharged in the form of a helix. And small
Because the projection parted by the groove is the same height as the sub cutting edge
Chips can be processed without cutting clogging, and chip processing performance
And the strength of the auxiliary cutting edge is reinforced.

Since the pressing surface of the throw-away tip, which is partitioned by the breaker groove, extends in the direction of the nose and has a large area, the contact surface of the wedge for fixing the chip is increased, and the tip is more securely fixed.

The main cutting edge is formed in a convex curve shape in plan view.
On the arc surface centered on the axis of the milling tool body.
The work material is attached to the main cutting edge.
At right angles to the bottom surface without forming a convex curved surface
Is cut into

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 5 show an embodiment of the present invention. FIG. 1 is a plan view of a throw-away tip, and FIG.
1 is a side view of FIG. 1, FIG. 3 is an enlarged sectional view taken along line AA of FIG. 1, FIG. 4 (a) is a plan view of the concave groove, and FIG. 4 (b) is BB of FIG.
5 is a diagram showing a state of attachment to a milling machine. FIG. 1 to 3, the indexable insert 7 has a substantially triangular flat plate shape, and an upper surface 9 substantially parallel to and opposed to a lower surface 8 serving as a seating surface of a cutting tool such as a milling cutter for mounting a cutting tool such as a milling cutter. Is formed. A main cutting edge 10 constituting each side of the triangle is formed in an arc shape having a large diameter in a plan view, and a nose portion between adjacent main cutting edges 10 includes an R portion 11a and a straight portion. Each of the sub-cutting blades 11 made of 11b is formed. In particular, the main cutting edge 10
Is formed in an arc shape in a plan view, the tip 7 is fixed to the cutting tool in an inclined state with a positive axial rake angle, and when the work material is to be cut at a right angle, the machined surface is set at a right angle. It becomes possible to cut. In this case, the main cutting edge 10
The arc shape of the above shows that the tip 7 is attached to the cutting tool,
It is desirable to form the cutting tool so as to be located on an arc surface centered on the axis L of the cutting tool. Also, the straight portion 1 of the sub cutting edge 11
1b is located near the other main cutting edge 10 adjacent to the main cutting edge 10 to which the R portion 11a is connected, and the indexable insert 7 is configured to be right-handed.

At the center of the upper surface 9 of the chip 7, there is provided a pressing surface 12 to be pressed by a wedge when it is mounted on a holder or the like. The pressing surface 12 is provided on each of the cutting blades 10 and 11.
And has a height that is the same as or slightly greater than A rake face between the main cutting edge 10 and the pressing surface 12 includes a main cutting edge 10
Flat land 13 and chip breaker groove 14
Are formed respectively. The breaker groove 14 has a maximum breaker width at the center of the main cutting edge 10 and
Are formed in a substantially arc shape so that the breaker width becomes smaller toward both end portions. In addition, in one end region of the breaker groove 14, the breaker width, which decreases in an arc shape toward the end portion, increases again at the bent portion 14a to form a small groove portion 15 to form the main cutting edge 10 And near the boundary between the cutting edge 11 and the flat cutting portion 11. The position where the small groove portion 15 in the breaker groove 14 is formed is provided at a position where chips generated from the work material at the time of low cutting can contact with the chip 7 attached to the cutting tool. In FIG. 1, it is provided at the left end of the main cutting blade 10.

The breaker groove 14 is formed as shown in FIG.
In the cross section taken along the line A, as viewed from the main cutting edge 10 in the direction of the pressing surface 12, a first surface 14 b having a downward slope (for example, an angle of 19 ° with respect to the lower surface) following the land portion 13 and a second surface parallel to the lower surface 8. Surface 14c and an upward gradient (for example, an angle 3 with respect to the lower surface 8) from the second surface 14c to the upright surface 12a of the pressing surface 12.
゜) and a third surface 14d.
In addition, the third surface 14d is not provided in the small groove portion 15 of the breaker groove 14, and is connected from the second surface 14c to a boundary surface of a protrusion described later. In each of the breaker grooves 14, a plurality of concave grooves 16 are provided, each extending from the first surface 14b to the third surface 14d, and having a substantially triangular shape in plan view and gradually increasing in width from the main cutting edge 10 side to the pressing surface 12 side. (Four in the figure). As shown in FIGS. 4A and 4B, the in-groove shape of the concave groove portion 16 has a concave curved surface shape. Moreover, the concave grooves 16 are separated from each other and arranged in a direction parallel to the main cutting edge 10. The groove 16 allows the breaker groove 1
The area where the chips running on the surface 4 contact the rake face is reduced.

In the nose portion between the adjacent breaker grooves 14, 14, a flat surface having substantially the same height as the sub-cutting edge 11 and extending from the ridge line of the sub-cutting edge 11 to the pressing surface 12. A protrusion 17 is formed (see FIG. 1). Projection 17
Is a pair of mutually inclined boundary surfaces 17a, 1 that rise in a tapered shape from the adjacent breaker grooves 14, 14, respectively.
7a, the width of the protrusion 17 is wide at the end on the side of the sub-cutting edge 11, and minimized at the constriction 17b of the small groove 15 of the breaker groove 14, and from this area toward the pressing surface 12 The width is gradually widened to form a shape connected to the pressing surface 12. Also, each boundary surface 17a is
The ends on the side of the sub-cutting edge 11 are connected to the ends of the R portion 11a and the straight portion 11b, respectively. The projecting portion 17 reinforces the strength of the sub-cutting edge 11, improves the chip controllability by the boundary surface 17a, and can reduce the cutting resistance.

As described above, the pressing surface 12 and the protruding portion 17 are separated by the breaker groove 14 including the small groove portion 15, and the pressing surface 12 is particularly extended in the direction of each nose as shown in FIG. ing. Thereby, the pressing surface 12 for pressing the chip 7 at the time of mounting the chip can be widened. Also, the boundary surface 17a of the projection 17 and the pressing surface 1
With the second raised surface 12a, the flow and curl of the chips can be made smooth.

In the side surface 19 between the upper and lower surfaces of the throw-away tip 7, the flank 19a of the main cutting edge 10 formed by the upper part of the side surface 19 corresponding to the main cutting edge 10 is formed in a plan view. It is formed in a curved shape with a certain clearance angle along the arc shape. Further, a lower portion 19b of the side surface extending from the flank surface 19a to the lower surface 8 is formed in a planar shape. The lower side surface 19b is inclined more than the flank 19a (see FIGS. 2 and 3). Thereby, when the indexable insert 7 is attached to the mounting seat of the cutting tool, the lower side surface 19b corresponding to the main cutting edge 10 forming each side is formed in a plane, so that the lower portion 19b is linearly formed with the mounting seat. Positioning can be performed and positioning becomes easy. On the other hand, when the main cutting edge 10 is formed into a curve in a plan view, and the entire side surface forming the flank is formed into a convex curved surface, accurate positioning with the mounting seat becomes difficult, and the side surface of the convex curved surface becomes difficult. Therefore, there is a drawback that the position is easily shifted from the mounting seat even after the mounting.

Since the present embodiment is constructed as described above, when cutting with the indexable insert 7, first, when attaching the insert 7 to a holder such as a face mill or a cutter, Since the lower side surface 19b adjacent to the lower surface 8 which is the seating surface is flat,
The positioning with the side surface of the mounting seat can be performed by the straight portion. In addition, as shown in FIG. 5, when the pressing surface 12 is pressed and fixed by the wedge 21, the area of the pressing surface 12 is set to be large, so that the contact surface of the wedge 21 can be made large, and the mounting can be performed more easily. Become sure and strong.

Then, with the chip mounted, the small groove portion 15 of the breaker groove 14 of the main cutting blade 10 for cutting is positioned in the low cutting area. When cutting at a low depth of cut, the sub cutting edge 11 and the main cutting edge 10
The chips generated by the cutting process travel through the small groove 15 of the breaker groove 14 and collide with one boundary surface 17 a of the projection 17 to be curled. Then, the chips are discharged in the form of a helix. In addition, since the protrusion 17 is at the same height as the sub-cutting edge 11, clogging of chips in the small groove 15 can be reduced. Further, when the work material is cut at a right angle, even when the indexable insert 7 is mounted at a predetermined axial rake angle, the main cutting edge 10 is formed in an arc shape in a plan view. In addition, the processing surface can be cut at right angles to the processing bottom surface without forming a convex curved surface (see the dashed line in FIG. 6). Thereby, processing accuracy is improved.

As described above, in the present embodiment, since the main cutting edge 10 is formed in an arc shape in plan view, the right-angled surface is suppressed by suppressing the processing surface from being curved as a convex curved surface at the time of right-angle cutting. Processing accuracy can be improved. At the same time,
When the throw-away tip 7 is mounted on the mounting seat, the lower side surface 19b is flat and can be positioned in a straight line, so that the positioning is easy and accurate, and it is hard to rattle after being fixed. Further, since the pressing surface 12 is widened, a large pressing area by the wedge can be taken, and firmly fixed.

In the above embodiment, the small groove 15 of the breaker groove 14 has a larger breaker width than the bent portion 14a. However, as shown by a dashed line in FIG.
The breaker width may be the same as 4a. or,
In the above-described embodiment, the throw-away tip 7 is configured to be right-handed, but needless to say, a left-handed configuration may be employed. If left-handed, small groove 15 in breaker groove 14
Is formed at the opposite end.

[0020]

As described above, in the indexable insert according to the present invention, the main cutting edge and the sub cutting edge are formed in a curved shape in plan view, and each side surface between the upper and lower surfaces is formed by the main cutting edge. Since it is formed of a convex curved side upper surface and a flat side lower surface forming a flank, it can be positioned in a straight line when mounting the throw-away tip to the mounting seat, making positioning easy and accurate. It can be firmly fixed by preventing rattling. Furthermore, the breaker width is mainly determined by the breaker width.
Flat so that it becomes maximum at the center of the blade and minimum at the nose
Since view substantially an arc shape, at the time of deep cuts, switching is generated
Debris can easily curl without causing chip clogging,
Easy to be served. Breaker width increases in low-cut area
Due to the formation of small grooves, it is generated at low depth of cut.
Chips are easy to curl and become wrapped and discharged
Easy to be. In addition, the strength of the secondary cutting edge is reinforced by the protrusion
Is done. Further, on the upper surface, the pressing surface for fixing the throw-away tip is a plane parallel to the lower surface that is separated by the breaker groove and extends in the direction of each nose, so that the area of the pressing surface is increased and the surface is more firm. The chip can be fixedly held. Also, when cutting at right angles, the processing surface with the main cutting edge is a convex curved surface
A right angle plane to the processing bottom by suppressing bending as
As a result, the processing accuracy can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view of a throw-away tip according to an embodiment of the present invention.

FIG. 2 is a plan view of the throw-away tip of FIG.

FIG. 3 is an enlarged cross-sectional view taken along line AA of the throw-away tip of FIG.

4A is an enlarged plan view of the concave groove portion of FIG. 1, and FIG. 4B is a cross-sectional view taken along line BB of FIG.

FIG. 5 is a view showing a state where the indexable insert is attached to a milling machine.

FIG. 6A is a view showing a relationship between a conventional throw-away tip and a processing surface, and FIG. 6B is a view showing an attachment angle of the throw-away tip in FIG.

[Explanation of symbols]

 7 indexable insert 10 main cutting edge 11 sub-cutting edge 12 pressing surface 14 breaker groove 15 small groove 19 side 19a flank 19b lower side

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-52-103081 (JP, A) JP-A-48-52078 (JP, A) JP-A-4-109805 (JP, A) 74905 (JP, U) Japanese Utility Model Application Hei 5-53822 (JP, U) Japanese Utility Model Application Hei 7-31202 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23B 27/14 B23B 27 / 16 B23B 27/22 B23C 5/06 B23C 5/20

Claims (3)

(57) [Claims] 1. A main cutting edge is formed on each side of a peripheral edge of an upper surface facing a lower surface forming a seating surface, a sub cutting edge is formed on a nose portion, and a breaker groove is formed on a rake surface of the upper surface. The main cutting edge is formed in a convex curved shape in a plan view, and on each side surface between upper and lower surfaces, a convex curved side surface forming a flank of the main cutting edge is provided. and lower side of the top and flat shape is formed, the blade
The groove has a maximum breaker width at the center of the main cutting edge.
And gradually becomes smaller as it approaches the nose.
It is approximately arc-shaped in plan view and front in the low cutting side area
Breaker width once increases toward the nose and gradually decreases
A small groove having a substantially small arc shape in a plan view is formed,
The sub-portion is adjacent to the sub-portion so as to be partitioned into small grooves.
Sub cutting edge extending from the ridge line of the cutting edge toward the center of the upper surface
It is characterized in that flat projections of the same height are formed
A throw-away tip. 2. A said upper surface, the pressing surface of the cutting insert for fixation, to claim 1, wherein the forming the lower surface and parallel planes extending divided by the breaker grooves in the nose portion direction The described throwaway tip. 3. A tip of a rolling tool body rotating around an axis.
3. The throwaway according to claim 1 or 2 on the outer periphery.
The insert positions its main cutting edge on the outer peripheral side of the tool body.
And, with the secondary cutting edge located on the tip side,
Slot that is attached in an inclined state with an axial rake angle
An away type milling tool, wherein the main cutting edge is
So that it is located on an arc plane centered on the axis of the cutting tool body
The main cutting edge faces the bottom surface.
Slotted to be cut at right angles
-Away milling tools.