JP2014028423A - Cutting insert, cutting edge replaceable end mill, and end mill body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting insert, a cutting edge replaceable end mill and an end mill body which can secure cutting edge strength in a peripheral cutting blade among cutting edges having recesses, prevent deviation of a cutting margin from occurring in a corner blade, suppress early wear and chipping of the cutting edge, and secure ramping performance, stably maintain high quality cutting work, and extend tool life.SOLUTION: A cutting insert 1A is detachably attached to the tip outer circumference of an end mil body. A cutting edge 15 includes: outer peripheral cutting blades 16 in which a virtual contour P forms a linear shape; corner blades 17 which are continuous to the outer peripheral cutting blades 16, and in which the virtual contour P forms a convex curve shape; and ramping blades 24 which are continuous to sides of the corner blades 17 opposite to outer peripheral cutting blades 16. Recesses 18 recessed to the virtual contour P are formed, in the peripheral cutting blades 16 and corner blades 17, when viewing a rake surface 12 in the front. The lengths N of the recesses 18 along the virtual contour P in the corner blades 17 are made shorter than the lengths M of the recesses 18 along the virtual contour P in the outer peripheral cutting blades 16.

Description

  The present invention relates to a cutting insert constituting a cutting edge of a blade edge replaceable end mill, a blade edge replaceable end mill to which the cutting insert is attached, and an end mill body thereof.

  Conventionally, as this type of blade-end-exchangeable end mill, for example, as shown in Patent Document 1 below, a plurality of cutting inserts are circumferentially spaced at the tip outer peripheral portion of an end mill body that has a cylindrical shape and is rotated around an axis. A device that is detachably mounted with an opening is known. The cutting insert has a plate-like insert body, one side facing the thickness direction of the insert body is a rake face, and the side face facing the direction intersecting the thickness direction of the insert body is a flank face. The intersecting ridge line between the surface and the flank is regarded as a cutting edge.

When the cutting insert is mounted on the end mill body, the cutting edge is positioned on the outer peripheral edge (straight main cutting edge) that is linear so as to be parallel to the axis of the end mill body, and on the distal end side of the outer peripheral edge. The corner blade (curved secondary cutting blade) that gradually forms a convex curve toward the inner side in the radial direction of the end mill body as it goes toward the tip side of the end mill body, and the outer edge of the corner blade on the opposite side (in the radial direction) It has a series of ramping blades (straight secondary cutting blades).
The blade end replaceable end mill of Patent Document 1 is a blade end replaceable radius end mill that performs shoulder processing, grooving processing, subduction processing, sumi R processing, and the like using the cutting insert configured as described above.

  On the other hand, as shown in the following Patent Document 2, there is known a blade edge exchange type end mill in which a concave portion (nick) is formed in a cutting blade of a cutting insert. By forming the recesses in the cutting edge in this manner, the chips are easily divided, chip disposal is improved, and impact reduction and cutting load can be reduced when biting the work material.

Here, for example, among the cutting blades of the cutting insert of Patent Document 1, it is conceivable to form a recess described in Patent Document 2 on the outer peripheral blade and the corner blade to obtain a blade-tip replaceable raffin gradient end mill. In this case, the cutting insert has a shape as shown in FIG. 10, for example.
Cutting inserts 101A to 101C for the blade-tip replaceable raffin gradient end mill shown in FIGS. 10 (a) to (c) are mounted on the same end mill main body, and in the state mounted on the end mill main body, The cutting inserts 101A to 101C are arranged so that the virtual contours that are the basic shapes of the cutting blades 115 coincide with each other, while the positions of the recesses are shifted in the direction along the virtual contours (the blade length direction of the cutting blade 115). It is supposed to be.

  Thus, by using a plurality of types of cutting inserts 101A to 101C (three in the example of FIG. 10) in which the positions of the recesses of the cutting edge 115 are different from each other, one of the cutting inserts 101A to 101C is used. Concavities and convexities projected (transferred) from the rotation trajectory of the cutting edge 115 (rotation trajectory around the axis of the end mill body) onto the work surface of the work material, in particular, the convex portion of the work surface, are caused by the cutting blade 115 of the other cutting insert. Each of them is cut into a smooth machined surface, and the machined surface quality can be improved.

JP 2000-42821 A JP 7-299636 A

However, the above-mentioned blade tip replaceable end mill has the following problems.
Of the cutting edges 115 of the cutting inserts 101A to 101C shown in FIGS. 10 (a) to 10 (c), in the outer peripheral edge 116 that is arranged far from the axis of the end mill body and has a high cutting speed, the thickness of the chips is also increased. Since the cutting load becomes large, it is necessary to ensure sufficient edge strength. Therefore, when determining the wave shape of the cutting edge 115 of these cutting inserts 101A to 101C, first, the concave portion of the outer peripheral blade 116 is set so as to ensure the strength of the cutting edge, and based on this concave portion (that is, the outer peripheral blade 116). The concave portion of the corner blade 117 is set so as to be equivalent to the length of the concave portion.

  However, while the cutting allowances (hereinafter referred to as cutting allowances) at the outer peripheral blades 116 of the respective cutting inserts 101A to 101C are easily made substantially equal to each other, the cutting allowances at the corner blades 117 of the respective cutting inserts 101A to 101C are made equal. That was difficult. That is, the corner blade 117 extends so as to be inclined with respect to the axis line of the end mill body (so-called cutting edge is in a sleeping state), and thus, like the outer peripheral blade 116 substantially parallel to the axis line of the end mill body. The cutting allowance could not be set evenly.

  Here, the cutting allowance of the corner blade 117 of the cutting inserts 101A to 101C will be specifically described. 11 (a) to 11 (c) show the cutting allowance at the corner blade 117 of each of the cutting inserts 101A to 101C when the cutting inserts 101A to 101C described above are mounted on the end mill body and cut. The cut portion of is colored black.

  As shown in FIGS. 11A to 11C, among these cutting inserts 101A to 101C, the cutting margin of the corner blade 117 in one cutting insert 101A is that of the corner blade 117 of the other cutting inserts 101B and 101C. It is larger than the cutting allowance. Thus, if the cutting allowance of the corner blades 117 of the cutting inserts 101A to 101C is uneven, the corner blade 117 of the predetermined cutting insert 101A having a high cutting load may be worn or lost early.

  In particular, as shown in FIGS. 11A to 11C, the cutting depth ap in the tool axial direction is smaller than the length in the axial direction of the concave portion (groove portion) that does not easily contribute to cutting in the corner blade 117. Are equal (or less), some of the corner blades 117 of these cutting inserts 101A to 101C do not function (in the example of FIG. 11, the corner blade 117 of the cutting insert 101B does not function). Further, the cutting load on the other corner blades 117 other than the some corner blades 117 is remarkably increased. That is, as the cutting amount (particularly, the cutting depth ap) becomes smaller, the balance of the cutting allowance for each cutting edge 115 of the cutting inserts 101A to 101C becomes worse, the tool generates vibration, and the cutting edge has a large cutting allowance. Chipping is likely to occur at 115. Therefore, in order to perform stable cutting, the lower limit value of the cutting depth cannot be reduced.

  By the way, referring to FIGS. 11A to 11C, the cutting margin of the corner blade 117 of the cutting insert 101A is larger than the cutting margin of the corner blade 117 of the cutting insert 101C. Further, the corner blade 117 of the cutting insert 101B hardly functions (there is no cutting allowance). For the purpose of equalizing these cutting allowances, for example, a ramping blade 118 (see FIG. 10) connected to the tip end portion of the corner blade 117 of the cutting insert 101A, that is, the inner peripheral side of the corner blade 117 (the side opposite to the outer peripheral blade 116). It is conceivable that a concave portion having a small length (that is, a narrow width) along the virtual contour line is formed in the connecting portion with the). This makes it easy to make the cutting allowances between the corner blades 117 uniform, but on the other hand, the strength of the edge of the ramping blade 118 cannot be secured, and the ramping performance may be reduced.

  On the other hand, in the cutting edges 115 of the cutting inserts 101A to 101C, instead of predetermining the wave shape of the outer peripheral edge 116 in advance as described above, first, the cutting edges 115 are formed with concave portions so that the cutting allowances of the corner edges 117 are equal. When formed, the length of the convex portion adjacent to the concave portion becomes small, so that there is a possibility that the cutting edge strength of the outer peripheral blade 116 having the wave shape based on the length cannot be secured.

  The present invention has been made in view of such circumstances, and among cutting edges having recesses, the cutting edge strength can be secured at the outer peripheral edge, and the cutting margin can be biased at the corner edge. Cutting inserts that can prevent premature wear and chipping of the cutting edge, as well as ensure ramping performance, stably maintain high-grade cutting, and extend the tool life. An object of the present invention is to provide an edge mill replaceable end mill and an end mill body.

In order to solve such problems and achieve the above object, the present invention proposes the following means.
That is, the present invention is a cutting insert that is formed in a columnar shape and is detachably mounted on the outer periphery of the end of the end mill body that rotates about the axis, and has a plate-like insert body, One surface facing the thickness direction is a rake surface, a side surface facing a direction intersecting the thickness direction of the insert body is a flank surface, and a cross ridge line between the rake surface and the flank surface is a cutting edge. The cutting edge includes an outer peripheral blade in which a virtual contour, which is a basic shape of the cutting blade, forms a linear shape, a corner blade that is connected to the outer peripheral blade, and the virtual contour forms a convex curve, and A ramping blade connected to the opposite side of the outer peripheral blade, and when viewed from the front side of the rake face, the outer peripheral blade and the corner blade of the cutting blade are recessed with respect to the virtual contour line. A recess is formed, The concave portion is not formed in the connection portion of the blade with the ramping blade, and the length of the concave portion along the virtual contour line in the corner blade is the length of the concave portion along the virtual contour line in the outer peripheral blade. It is characterized by being smaller than the length.

  When the cutting insert of the present invention is mounted on the outer periphery of the tip end of the end mill body and the work material is cut (turned), the outer peripheral edge of the cutting insert has an outer peripheral edge at the outer peripheral end of the end mill main body. The corner blade is disposed radially inward from the outer peripheral blade at the outer peripheral end of the end mill body. In addition, the ramping blade is disposed radially inside the corner blade. And when the end mill body is rotated around the axis and cut into the work material with the cutting insert, the cutting edge of the cutting insert has a corrugated shape with the outer peripheral edge and the corner edge having a recess, The entire length of the cutting edge does not bite into the work material at one time, but gradually bites into the work material from each convex part adjacent to the concave part. Effects such as reduction of cutting load and improvement of chip disposal are obtained.

  In the cutting insert of the present invention, the cutting speed is arranged closer to the axis than the outer peripheral blade with respect to the length of the concave portion along the virtual contour line of the outer peripheral blade arranged far from the axis and having a high cutting speed. By reducing the length of the concave portion along the virtual contour line of a slow corner blade, the following remarkable effects can be obtained.

  That is, it is necessary to sufficiently secure the edge strength (cutting edge strength) in the outer peripheral blade where the cutting speed is high and the thickness of the chip is increased. According to the present invention, corresponding to the length of the concave portion along the virtual contour line of the outer peripheral blade, the cutting edge length at the convex portion cut into the work material is secured and the strength of the blade edge is increased. Thus, chipping and chipping are suppressed, and stable cutting can be maintained.

  On the other hand, a corner blade whose cutting speed is slower than the outer peripheral blade and the thickness of the chip is thinner does not require the edge strength as much as the outer peripheral blade. Therefore, in the present invention, the length of the concave portion along the virtual contour line of the corner blade is set smaller than the length of the concave portion along the virtual contour line of the outer peripheral blade. Thus, by shortening the length of the recesses of the corner blade, the arrangement interval between the recesses adjacent to each other in the blade length direction (the direction along the virtual contour line) can be set small in the corner blade, and further adjacent to these recesses. It is also possible to reduce the arrangement interval between the convex portions. Thereby, for example, a plurality of cutting inserts are attached to the outer peripheral end of the end mill body with an interval around the axis, and the positions in the direction along the virtual contours of the recesses between the cutting edges in the rotation trajectory of these cutting inserts are shifted. Thus, the cutting margins of the corner blades of the cutting inserts can be made substantially equal to each other.

Specifically, unlike the present invention, for example, as in the conventional cutting inserts 101A to 101C shown in FIGS. 10 and 11 described above, the length of the concave portion along the virtual contour line of the corner blade 117 is set to the outer peripheral blade. 116, the cutting allowance of the corner blade 117 of the predetermined cutting insert 101A is larger than the cutting allowance of the corner blade 117 of the other cutting inserts 101B and 101C. As the size increases, the cutting load of the corner blade 117 of the cutting insert 101A becomes larger than the others, and the corner blade 117 may be prematurely worn or chipped. In particular, as shown in FIGS. 11A to 11C, the cutting depth (cutting amount) ap in the tool axis direction is the length in the axial direction of the concave portion (groove portion) that hardly contributes to cutting in the corner blade 117. If these are equal (or less), some of the corner blades 117 of these cutting inserts 101A to 101C will not function, and other corner blades 117 other than the some of the corner blades 117 will not function. The cutting load will increase significantly.
On the other hand, according to the present invention, in the cutting edge of each cutting insert, not only the cutting allowance between the outer peripheral blades but also the cutting allowance between the corner blades is substantially equal, that is, the cutting of the corner blade of the predetermined cutting insert. The load is prevented from becoming larger than the corner blades of other cutting inserts, and the corner blades are prevented from being worn early, chipped or chipped. In particular, even when the cutting depth ap is small, the cutting depth ap is less likely to be smaller than the length in the axial direction of the concave portion of the corner blade. Can be suppressed.

  Furthermore, since the concave portion is not formed in the connecting portion of the corner blade with the ramping blade, the strength of the edge of the ramping blade is sufficiently ensured, and the ramping performance in subduction processing or the like is stably maintained.

  As described above, according to the cutting insert of the present invention, a concave portion is provided in the cutting edge, and effects such as shock mitigation, reduction of cutting load, and improvement of chip disposal are achieved. Cutting edge strength can be secured, and it is possible to prevent the occurrence of uneven cutting allowance in the corner blade, thereby suppressing the early wear and chipping of the cutting edge and ensuring the ramping performance, High-quality cutting can be stably maintained and the tool life can be extended.

  Further, in the cutting insert of the present invention, the outer peripheral edge and the corner blade are formed with a convex portion adjacent to the concave portion, and the convex portion extends along the virtual contour line, and the virtual edge in the corner blade is formed. The ratio n / N of the length n of the convex portion along the virtual contour line to the length N of the concave portion along the contour line is the virtual to the length M of the concave portion along the virtual contour line in the outer peripheral blade. It is good also as larger than ratio m / M of the length m of the said convex part along an outline.

  In this case, the unevenness projected on the work surface of the work material from the rotation trajectory of the cutting edge of one cutting insert, in particular, the convex portion of the work surface is cut by the cutting blades of the other cutting inserts, respectively, to achieve smooth machining. The surface quality can be improved. In order to reliably improve the processing quality, it is necessary to overlap the rotation trajectories of the convex portions of the corner blade and the outer peripheral blade of each cutting insert. When the ratios n / N and m / M of the lengths n and m of the convex portions along the virtual contour line to the lengths N and M of the concave portion along the virtual contour line are constant, the virtual contour line Due to the difference in the length of the concave portions along, the overlap length of the corner blade becomes smaller than that of the outer peripheral blade, and the processing quality of the processing surface cut by the corner blade is higher than the processing quality of the processing surface cut by the outer peripheral blade. It will be inferior. Therefore, as in the above-described configuration of the present invention, the ratio n / N of the length n of the convex portion along the virtual contour line to the length N of the concave portion along the virtual contour line in the corner blade is set as an outer peripheral blade. By making the ratio m / M of the length m of the convex part along the virtual contour line to the length M of the concave part along the virtual contour line in FIG. The lengths can be made substantially equal, and the difference in processing quality between the processed surfaces cut by the corner blade and the outer peripheral blade can be reduced.

  In the cutting insert of the present invention, the rake angle of the corner blade may be larger than the rake angle of the outer peripheral blade.

  In this case, since the rake angle in the outer peripheral blade with high cutting speed and thick chip is reduced, the cutting edge strength in the outer peripheral blade is ensured, and chipping and chipping are effectively suppressed. Become. On the other hand, in the corner blade having a cutting load smaller than that of the outer peripheral blade, the rake angle is increased, so that a sharp sharpness can be secured, the cutting resistance is reduced, and the processing quality is improved.

  In the cutting insert of the present invention, the rake angle of the corner blade may be increased from the outer peripheral blade toward the ramping blade side.

  In this case, the corner edge rake angle is reduced at the peripheral blade side of the corner blade where the cutting speed is high and the thickness of the chip is thick (that is, the cutting load is large). , Chipping and defects are suppressed. On the other hand, among the corner blades, the cutting speed is slow and the thickness of the chip is thin (that is, the cutting load is small) on the ramping blade side, since the rake angle of the corner blade is increased, a sharp sharpness can be secured, Cutting resistance is reduced and processing quality is improved.

  Further, according to the present invention, a plurality of insert mounting seats are formed around the axis of the end mill body on the outer periphery of the end mill body having a cylindrical shape, and a plurality of types of cutting inserts can be attached to and detached from these insert mounting seats. The cutting edge replaceable end mill mounted on the cutting mill includes the above-mentioned cutting insert as the cutting insert, and the virtual contour line of the outer peripheral blade is the axis of the end mill body among the cutting edges of the cutting insert. The virtual contour line of the corner blade extends toward the tip side of the end mill body and gradually extends inward in the radial direction perpendicular to the axis, and the plurality of types of cutting inserts are The positions of the recesses are arranged so that the virtual contour lines of the cutting edges coincide with each other in a rotation locus around the axis. Characterized in that it is offset in a direction along the imaginary contour lines.

  According to the cutting edge replaceable end mill of the present invention, the position of the recesses of the cutting inserts of the cutting inserts can be determined by the simple operation of simply mounting a plurality of types of cutting inserts on the insert mounting seat of the end mill body. Are shifted from each other in the direction along the edge (that is, the blade length direction of the cutting edge), and the work surface quality of the work material can be improved. That is, when these cutting inserts are attached to the end mill body, troublesome work such as adjusting the cutting edge position is unnecessary, and the workability is excellent.

  Further, the present invention is an end mill main body used in the above-described blade edge replaceable end mill, and is arranged on the outer peripheral surface of the end mill main body on the rear side in the tool rotation direction of the insert mounting seat, and A groove extending around the axis is formed corresponding to the concave portion of the cutting edge.

  According to the end mill body of the present invention, since the groove is formed on the outer peripheral surface of the end mill body corresponding to the recess of the cutting edge of the cutting insert attached to the insert mounting seat, the cutting insert is used as the insert mounting seat. It is possible to prevent incorrect mounting when mounting. That is, a predetermined cutting insert having a recessed portion of a cutting edge corresponding to a groove formed on the rear side in the tool rotation direction of the predetermined insert mounting seat is selected from a plurality of types of cutting inserts, and the insert mounting seat is selected. All you need to do is install it, and you can easily and accurately install the cutting insert.

  In addition, since a groove is formed in the end mill body corresponding to the concave portion of the cutting edge of the cutting insert, a rib or the like adjacent to the groove (a groove on the outer peripheral surface of the end mill body) is formed on the convex portion adjacent to the concave portion. The part of the end mill body is secured, while preventing the contact between the outer peripheral surface of the end mill body and the processed surface of the work material and ensuring the quality of the processed surface. The seating stability of the cutting insert with respect to the insert mounting seat can be enhanced.

  According to the cutting insert, the cutting edge replaceable end mill and the end mill body of the present invention, among cutting edges having recesses, the cutting edge strength can be secured at the outer peripheral cutting edge, and the cutting margin can be biased at the corner cutting edge. Thus, early wear and chipping of the cutting edge can be suppressed, and the ramping performance can be secured, high-quality cutting can be stably maintained, and the tool life can be extended.

It is a perspective view which shows the blade-tip-exchange-type end mill which concerns on one Embodiment of this invention. It is the front view which looked at the blade-tip-exchange-type end mill of FIG. 1 from the tool tip. It is the side view which looked at the blade-tip-exchange-type end mill of FIG. 2 from the arrow A direction. It is the side view which looked at the blade-tip-exchange-type end mill of FIG. 2 from the arrow B direction. It is a perspective view which shows multiple types of cutting insert used for a blade-tip-exchange-type end mill. It is a top view which shows the cutting insert. It is a fragmentary sectional view explaining the XX cross section of FIG. 6, and the YY cross section. It is a figure explaining the cutting allowance in the corner blade of multiple types of cutting insert. It is a perspective view which shows the modification of multiple types of cutting insert. It is a perspective view which shows the multiple types of cutting insert used for the conventional blade-tip-exchange-type end mill. It is a figure explaining the cutting allowance in the corner blade of the conventional multiple types of cutting insert.

Hereinafter, a blade-tip replaceable end mill 10 according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1 to FIG. 6, the cutting edge replaceable end mill 10 of the present embodiment includes a plurality of types of cutting inserts 1 </ b> A to 1 </ b> C for roughing having a cutting edge 15 having a recess (nick) 18. These are cutting edge-exchangeable roughing end mills that are detachably attached to the outer periphery of the end of an end mill body (holder) 2 that is rotated around an axis O. These cutting inserts 1A to 1C are made of the axis O of the end mill body 2. While the virtual contour line P (see FIG. 6), which is the basic shape of the cutting edge 15, is arranged so as to coincide with each other in the rotation locus around, the positions of the concave portions 18 are in the direction along the virtual contour line P ( The cutting locus 15 is shifted in the direction of the blade length), and the rotation trajectory of all the cutting edges 15 is substantially cylindrical. As shown in FIG. 5, in this embodiment, three types of cutting inserts 1 </ b> A to 1 </ b> C are used. P is shifted in the direction along P and attached to the end mill main body 2 (that is, the phase of the concave portion 18 is shifted). They are shifted so that they are even (3 equal parts). However, these cutting inserts 1 </ b> A to 1 </ b> C are not limited to the above three equal parts, as long as the positions of the recesses 18 between the cutting edges 15 are shifted in the direction along the virtual contour line P.

In addition, the blade tip replaceable end mill 10 has an outer peripheral blade 16 in which the rotation trajectory around the axis O of the end mill main body 2 of the cutting blade 15 of the cutting inserts 1A to 1C is located at the outer peripheral end of the end mill main body 2 in the cutting blade 15. , The end mill body 2 is linearly formed so as to be parallel to the axis O of the end mill body 2, while the corner blade 17 positioned at the outer peripheral end of the end mill body 2 gradually moves toward the tip end side of the end mill body 2. This is also a radius end mill with a replaceable cutting edge, which has a convex curve shape toward the inside in the radial direction.
That is, the blade edge replaceable end mill 10 of the present embodiment is a blade edge replaceable raffin gradient end mill.

This blade-tip replaceable end mill 10 has a rear end portion (upper end portion in FIGS. 3 and 4) of the end mill body 2 in the axis O direction that is rotatably held by a spindle of a machine tool (not shown). The workpiece is cut (rolled) by the cutting edge 15 of the cutting inserts 1A to 1C by being fed in the direction intersecting the axis O or the direction of the axis O while being rotated in the tool rotation direction T. This is a cutting tool with replaceable cutting edge.
In the present specification, the side opposite to the main axis of the machine tool along the direction of the axis O of the end mill body 2 (the lower side in FIGS. 1, 3 and 4) is referred to as the front end side. The main shaft side (the upper side in FIGS. 1, 3 and 4) is referred to as the rear end side. A direction orthogonal to the axis O is referred to as a radial direction, and a direction around the axis O is referred to as a circumferential direction.

  The end mill main body 2 is made of a steel material or the like, and a plurality of chip pockets 3 are formed on the outer peripheral portion of the end mill at intervals in the circumferential direction. In the present embodiment, three tip pockets 3 are formed so as to cut out the outer peripheral portion of the tip end of the end mill main body 2 at intervals in the circumferential direction. It opens toward the outside in the direction. In addition, recessed insert mounting seats 4 </ b> A to 4 </ b> C are formed on a wall surface facing the tool rotation direction T in the chip pocket 3.

  One type of cutting insert corresponding to a predetermined insert mounting seat among the plurality of types of cutting inserts 1A to 1C is detachably mounted on these insert mounting seats 4A to 4C. The wall surfaces facing the tool rotation direction T in the insert mounting seats 4A to 4C are the mounting surfaces of the cutting inserts 1A to 1C. The mounting surfaces are inserted into through holes 20 described later of the cutting inserts 1A to 1C. A screw hole 6 into which the clamp screw 5 is screwed is formed. In the present embodiment, two screw holes 6 are formed on the mounting surfaces of the insert mounting seats 4A to 4C corresponding to the number (two) of the through holes 20 of the cutting inserts 1A to 1C.

  In addition, these insert mounting seats 4A to 4C are formed corresponding to the shapes of the cutting inserts 1A to 1C to be mounted and are different in shape from each other. When an incorrect cutting insert other than the insert is to be mounted, the operator can easily recognize the incorrect mounting.

  Further, on the outer peripheral surface of the end mill main body 2, between the chip pockets 3 adjacent in the circumferential direction, corresponding to the concave portion 18 of the cutting edge 15 of the cutting inserts 1 </ b> A to 1 </ b> C and the convex portion 19 adjacent to the concave portion 18. Grooves 7 and ribs 8 extending in the circumferential direction are formed. These grooves 7 and ribs 8 are arranged on the rear side in the tool rotation direction T of the insert mounting seats 4A to 4C, and a groove portion 22 to be described later of the flank 14 of a predetermined cutting insert mounted on the predetermined insert mounting seat. And it is formed so as to continue to the rib portion 23.

That is, the grooves 7 and the ribs 8 positioned between the chip pockets 3 correspond to the insert mounting seats 4A to 4C adjacent to the front side in the tool rotation direction T and the cutting inserts 1A to 1C attached thereto, respectively. While being formed, the grooves 7 and the ribs 8 located between the chip pockets 3 have different shapes.
Specifically, on the flank 14 of the cutting insert, the groove 22 is connected to the rear side of the tool rotation direction T of the groove 22 in the same direction as the axis O direction of the end mill body 2, and the groove 7 is continuous. 23, the rib 8 is connected to the rear side of the tool rotation direction T with the same position in the axis O direction.

  As shown in FIGS. 5 and 6, the cutting inserts 1 </ b> A to 1 </ b> C have a vertically long insert body 11 made of a hard material such as cemented carbide. Of the pair of surfaces facing the thickness direction of the insert body 11, the upper surface (one surface) is a rake face 12, and when the cutting inserts 1A to 1C are mounted on the end mill body 2, the rake face 12 is a tool. It faces the rotation direction T. Moreover, the lower surface (other surface) of the pair of surfaces facing the thickness direction of the insert body 11 is a seating surface 13 that comes into contact with the mounting surfaces of the insert mounting seats 4A to 4C (see FIG. 2). reference).

  Further, in the insert main body 11, the insert main body 11 is disposed around the rake face 12 and the seating surface 13 and faces a direction intersecting the thickness direction of the insert main body 11 (specifically, a direction substantially perpendicular to the thickness direction). The side surface is a flank 14. Further, in the insert main body 11, the intersecting ridge line between the rake face 12 and the flank face 14 is a cutting edge 15.

  Since this cutting edge 15 is a cutting edge of a radius end mill of the blade tip exchange type as described above, its basic shape is shown by a two-dot chain line (symbol P) in FIG. 6 when viewed from the direction facing the rake face 12. As shown in the drawing, an outer peripheral blade 16 extending linearly in the longitudinal direction of the insert body 11 (vertical direction in FIG. 6), and a corner blade that is connected to one end of the outer peripheral blade 16 to form a substantially ¼ arc shape. 17 and a linear ramping blade 24 connected to the opposite side of the outer peripheral blade 16 of the corner blade 17.

Such a basic shape of the cutting edge 15 is referred to as a virtual contour line P of the cutting edge 15 in this specification. That is, the cutting edge 15 extends so that the virtual contour P is parallel to the axis O of the end mill body 2 when the cutting inserts 1 </ b> A to 1 </ b> C are attached to the end mill body 2. A corner blade 17 which is located on the distal end side of the outer peripheral blade 16 and gradually extends toward the inner side in the radial direction as the virtual contour line P moves toward the distal end side, and a radially inner side of the corner blade 17 And a ramping blade 24 that gradually extends from the corner blade 17 toward the rear end side as it is spaced radially inward.
In a state where these cutting inserts 1A to 1C are mounted on the insert mounting seats 4A to 4C of the end mill body 2, the virtual contour lines P of the cutting edges 15 of the cutting inserts 1A to 1C are mutually around the axis O of the end mill body 2. The rotation trajectories are matched.

In the present embodiment, the virtual contour P of the cutting edge 15 is provided in two-fold symmetry (180 ° rotational symmetry) with respect to an insert center line (not shown) extending in the thickness direction of the insert body 11 through the center of the rake face 12. Therefore, a pair of cutting edges 15 are also formed.
Further, the insert body 11 is formed with a through hole 20 that penetrates the insert body 11 in the thickness direction and opens to the rake face 12 and the seating face 13. As shown in FIG. 6, in this embodiment, a pair of through-holes 20 having the same shape and the same size are arranged in the longitudinal direction of the insert body 11 across the insert center line when viewed from the direction facing the rake face 12. It is formed as follows.
Also, what is indicated by reference numeral 21 on the rake face 12 is a used blade confirmation index (used blade confirmation mark) disposed close to one of the pair of cutting edges 15. The cutting inserts 1 </ b> A to 1 </ b> C are 180 ° rotationally symmetric bodies around the insert center line except for the used blade confirmation index 21.

  Moreover, since the cutting edge 15 of the cutting insert 1A-1C of this embodiment mentioned above is also a cutting edge of a cutting edge exchange-type roughing end mill, seeing the rake face 12 as shown in FIG. 15, the outer peripheral edge 16 and the corner edge 17 are formed with recesses 18 that are recessed with respect to the virtual contour line P at an interval, and the outer peripheral edge 16 and the corner edge 17 have a wave shape. .

  Specifically, in the top view of the insert shown in FIG. 6, the concave portion 18 of the cutting edge 15 has a concave curved shape, and forms a waveform of the cutting edge 15 together with the concave portion 18 to be adjacent to the concave portion 18. Reference numeral 19 denotes a straight line or a convex curve having a radius of curvature larger than that of the recess 18 along the virtual contour P of the cutting edge 15. In FIG. 6, the convex portion 19 of the outer peripheral blade 16 is linear along the virtual contour P portion of the outer peripheral blade 16, and the convex portion 19 of the corner blade 17 is the virtual contour line of the corner blade 17. A convex curve is formed along the P portion. In addition, the connection end of the recessed part 18 and the convex part 19 in the cutting edge 15 is made into the convex curve shape, and, thereby, the recessed part 18 and the convex part 19 are connected smoothly.

  In the cutting inserts 1 </ b> A to 1 </ b> C, the length N of the recess 18 along the virtual contour P in the corner blade 17 of the cutting blade 15 is greater than the length M of the recess 18 along the virtual contour P in the outer peripheral blade 16. It has been made smaller.

  That is, in this embodiment, since the length N of the concave portion 18 of the corner blade 17 is small, the arrangement interval between the concave portions 18 adjacent to each other in the blade length direction in the corner blade 17 is also reduced. 15, the wave-like wavelength formed by the concave portion 18 and the convex portion 19 in the corner blade 17 is made smaller than the wave-shaped wavelength formed by the concave portion 18 and the convex portion 19 in the outer peripheral blade 16.

  Specifically, the length n of the convex portion 19 along the virtual contour line P with respect to the length N of the concave portion 18 along the virtual contour line P in the corner blade 17 when the rake face 12 is viewed in front as shown in FIG. The ratio n / N is larger than the ratio m / M of the length m of the convex portion 19 along the virtual contour P to the length M of the concave portion 18 along the virtual contour P in the outer peripheral edge 16. In addition, about the cutting edge 15 of the cutting insert 1B shown by FIG.5 (b), the position along the virtual outline P of the recessed part 18 and the convex part 19 with respect to each cutting edge 15 of other cutting insert 1A, 1C ( That is, the relationship of the above ratios is exceptionally different for the purpose of shifting the phase of the unevenness and smoothly connecting the corner blade 17 and the outer peripheral blade 16.

  Here, shifting the phase of the irregularities specifically means that the corresponding convex portions 19 of the cutting edges 15 of the cutting inserts 1A to 1C overlap in the blade length direction (direction along the virtual contour line P). In particular, the protrusions 19 (portions indicated by reference numeral 16) of the outer peripheral blades 16 of the cutting inserts 1A and 1C shown in FIGS. 5A and 5C are surely overlapped with each other. It is desirable to make it. In order to reliably obtain this configuration, the ratio n / N is set larger than the ratio m / M.

  Further, corresponding to the concave portion 18 and the convex portion 19 of the cutting edge 15, the flank 14 of the insert body 11 extends from the rake face 12 to reach the seating face 13 as shown in FIG. 5. A plurality of groove portions 22 and rib portions 23 are formed so as to be alternated in the insert circumferential direction. In other words, since the groove portion 22 and the rib portion 23 are formed on the flank 14, the cutting edge 15 formed at the intersecting ridge line between the flank 14 and the rake face 12 has the concave portion 18 and the convex portion 19. An uneven shape (wave shape) is formed. Accordingly, the cutting edge 15 is generated by cutting only the convex portion 19 of the concave-convex shape, and the chips are divided at the concave portion 18.

  The cutting inserts 1A to 1C of the present embodiment are inclined so that the flank 14 gradually recedes from the rake face 12 to the seating face 13 side including the groove 22 and the rib part 23. The positive insert is provided with a clearance angle 15 in advance. Further, the entire seating surface 13 is a plane perpendicular to the thickness direction, whereas the rake face 12 is directed toward the inner side of the rake face 12 at the peripheral edge along the cutting edge 15. A positive surface that gradually recedes in the thickness direction is formed, and a portion including the opening portion of the through hole 20 on the inner side in the plane direction than the positive surface is a plane perpendicular to the thickness direction.

  6 and FIG. 7, the rake angle C (for example, the rake angle in the XX cross section of FIG. 6) of the cutting edges 15 among the cutting edges 15 is the rake angle C (for example, the rake angle C of the outer peripheral edge 16). It is made larger than the rake angle in the YY section of FIG. In the present embodiment, the rake angle C of the cutting edge 15 is −10 ° to 15 °. Further, the rake angle C of the corner blade 17 is increased continuously or stepwise from the outer peripheral blade 16 toward the ramping blade 24 side.

  In FIG. 7, in this embodiment, chamfer honing is formed on the cutting edge 15, the honing width E of the chamfer honing is 0.2 mm, and the honing angle F is 12 °. Instead of forming chamfer honing on the cutting edge 15, round honing may be formed. Further, a land is formed on the rake face 12 side of the cutting edge 15, and the land width D of the land is 0.7 mm. However, each said dimension is an example and is not limited to this embodiment.

  Further, as shown in FIG. 2, when the flank 14 of the cutting inserts 1 </ b> A to 1 </ b> C is viewed from the front of the tool, the corner blade 17 of the cutting blade 15 is a convex curve protruding in the thickness direction of the insert body 11. It has a shape. Further, as shown in FIG. 4, when the flank 14 of the cutting insert 1 </ b> A is viewed from the front in the tool radial direction, the outer peripheral edge 16 of the cutting edges 15 is separated from the corner edge 17 (after the end mill body 2. Inclined and extended so as to gradually recede in the thickness direction (toward the end side).

  In FIG. 6, of the pair of cutting edges 15 of the insert body 11, an obtuse angle is formed between the corner edge 17 of the one cutting edge 15 and the corner edge 17 at the end opposite to the outer peripheral edge 16. A ramping blade 24 is formed so as to intersect the corner blade 17 and extend linearly. The ramping blade 24 connects the end of the corner blade 17 of one of the cutting edges 15 and the end of the outer peripheral edge 16 of the other cutting edge 15, and the cutting inserts 1 </ b> A to 1 </ b> C are mounted on the end mill body 2. Sometimes, the end mill body 2 is disposed so as to protrude from the front end surface. The ramping blade 24 is cut into a work material when the blade end replaceable end mill 10 sinks as shown in FIG. 2 of Patent Document 1 (Japanese Patent Laid-Open No. 2000-42821), for example.

  In addition, as shown in FIG. 6, the concave portion 18 is not formed in the connection portion between the corner blade 17 and the ramping blade 24. That is, the corner blade 17 continues from the convex portion 19 to the ramping blade 24, and the concave portion 18 of the corner blade 17 is located at a position away from the ramping blade 24 (part other than the portion connected to the ramping blade 24). Is formed.

  When the workpiece is cut (turned) by using the edge-replaceable end mill 10 of the present embodiment described above, the outer peripheral edge 16 of the cutting edges 15 of the cutting inserts 1 </ b> A to 1 </ b> C is the end mill body 2. The corner blade 17 is disposed at the outer peripheral end, and is disposed radially inward from the outer peripheral blade 16 at the outer peripheral end of the end mill body 2. Further, the ramping blade 24 is disposed on the inner side in the radial direction of the corner blade 17. Then, when the end mill body 2 is rotated around the axis O and cut into the work material by the cutting inserts 1A to 1C, the outer peripheral edge 16 and the corner edge 17 of the cutting edges 15 of the cutting inserts 1A to 1C are recessed. By being made into a wave shape having 18, the entire cutting edge does not bite into the work material at once, and gradually bites into the work material from each convex part 19 adjacent to the concave part 18. At the same time, the chips are easily divided finely, and effects such as shock reduction, reduction of cutting load, and improvement of chip disposal are obtained.

  In the cutting inserts 1 </ b> A to 1 </ b> C of the present embodiment, the length M of the concave portion 18 along the virtual contour P of the outer peripheral blade 16 that is arranged far from the axis O and has a higher cutting speed than the outer peripheral blade 16. By reducing the length N of the recess 18 along the virtual contour line P of the corner blade 17 which is disposed near the axis O and has a slow cutting speed, the following remarkable effects are obtained.

  That is, it is necessary to sufficiently secure the edge strength (cutting edge strength) in the outer peripheral edge 16 where the cutting speed is high and the thickness of the chips is increased. According to this embodiment, the cutting edge length (blade length) at the convex portion 19 that cuts into the work material is ensured corresponding to the length M of the concave portion 18 along the virtual contour line P of the outer peripheral blade 16. In addition, the strength of the blade edge is increased, thereby suppressing chipping and chipping and maintaining stable cutting.

  On the other hand, in the corner blade 17 whose cutting speed is slower than that of the outer peripheral blade 16 and the thickness of the chips is thinner, the edge strength as high as that of the outer peripheral blade 16 is not required. Therefore, in the present embodiment, the length N of the recess 18 along the virtual contour P of the corner blade 17 is set to be smaller than the length M of the recess 18 along the virtual contour P of the outer peripheral blade 16. Thus, by shortening the length N of the concave portion 18 of the corner blade 17, the arrangement interval between the concave portions 18 adjacent to each other in the blade length direction (the direction along the virtual contour line P) can be set small. Further, the arrangement interval between the convex portions 19 adjacent to the concave portions 18 can be reduced. As a result, as described in the present embodiment, a plurality of types of cutting inserts 1A to 1C are mounted on the outer periphery of the end of the end mill body 2 with an interval around the axis O, and the rotation trajectories of these cutting inserts 1A to 1C. When the positions of the cutting edges 15 in the direction along the virtual contour P of the recesses 18 are shifted (that is, the phases of the recesses 18 are shifted), the cutting margin of the corner blades 17 of the cutting inserts 1A to 1C is set. Can be made substantially equal to each other.

  Specifically, unlike the present embodiment, for example, as in conventional cutting inserts 101A to 101C shown in FIG. 10 and FIG. When the same setting as the length of the recess along the contour line is made, the cutting allowance of the corner blade 117 of the predetermined cutting insert 101A is larger than the cutting allowance of the corner blade 117 of the other cutting inserts 101B and 101C, The cutting load of the corner blade 117 of the cutting insert 101 </ b> A becomes larger than the others, and the corner blade 117 may be worn out early or missing. In particular, as shown in FIGS. 11A to 11C, the depth of cut (cut amount) ap in the direction of the tool axis O is the direction of the axis O of the recess (groove) that hardly contributes to cutting at the corner blade 117. Of the cutting inserts 101 </ b> A to 101 </ b> C, some of the corner blades 117 do not function, and other corner blades other than the some corner blades 117. The cutting load with respect to 117 will increase notably.

On the other hand, FIGS. 8A to 8C show the cutting allowances at the corner blades 17 of the cutting inserts 1A to 1C when the cutting inserts 1A to 1C of the present embodiment are mounted on the end mill body 2 and cut. The cut portion of the work material W is expressed in black.
According to the present embodiment, in the cutting edge 15 of each of the cutting inserts 1A to 1C, not only the cutting allowance of the work material W between the outer peripheral edges 16 but also the cutting of the corner edges 17 as shown in FIG. The cutting allowance of the material W is also substantially equal, that is, the cutting load of the corner blade 17 of a predetermined cutting insert is prevented from becoming larger than the corner blade 17 of another cutting insert. Are prevented from wearing out early, chipping and chipping. In particular, even when the cutting depth ap is small, the cutting depth ap is less likely to be smaller than the length of the concave portion 18 of the corner blade 17 in the axis O direction. The bias can be remarkably suppressed.

  Further, since the concave portion 18 is not formed in the connecting portion of the corner blade 17 with the ramping blade 24, the blade tip strength of the ramping blade 24 is sufficiently secured, and the ramping performance in subduction processing or the like is stabilized. Maintained.

  As described above, according to the cutting inserts 1A to 1C of the present embodiment, the cutting edge 15 is provided with the recess 18 to provide effects such as shock reduction, reduction of cutting load, improvement of chip disposal, and the like. Of these, the cutting edge strength can be secured at the outer peripheral edge 16 and the cutting edge can be prevented from being biased at the corner edge 17, thereby suppressing early wear and chipping of the cutting edge 15. In addition, the ramping performance is secured, high-quality cutting is stably maintained, and the tool life can be extended.

  Further, in the cutting inserts 1A to 1C of the present embodiment, the outer peripheral blade 16 and the corner blade 17 are formed with a convex portion 19 adjacent to the concave portion 18, and the convex portion 19 extends along the virtual contour line P. The ratio n / N of the length n of the convex portion 19 along the virtual contour P to the length N of the concave portion 18 along the virtual contour P in the corner blade 17 is the concave portion 18 along the virtual contour P in the outer peripheral blade 16. Since the ratio m / M of the length m of the convex portion 19 along the virtual contour line P with respect to the length M is increased, the following effects are produced.

  That is, with this configuration, the projections and depressions projected onto the work surface of the work material from the rotation trajectory of the cutting edge 15 of one cutting insert, in particular the convex portions of the work surface, are respectively cut by the cutting edges 15 of the other cutting inserts. And a smooth machined surface, and the quality of the machined surface can be improved. In order to reliably improve the processing quality, it is necessary to overlap the rotation trajectories of the convex portions 19 of the corner blades 17 and the outer peripheral blades 16 of the cutting inserts 1A to 1C. In the corner blade 17 and the outer peripheral blade 16, the ratios n / N and m / M of the lengths n and m of the convex portions 19 along the virtual contour P to the lengths N and M of the concave 18 along the virtual contour P are constant. If there is, the overlap length of the corner blade 17 becomes smaller than the outer peripheral blade 16 due to the difference in the length of the concave portion 18 along the virtual contour P, and the processing quality of the processed surface cut by the corner blade 17 is the outer peripheral blade. This is inferior to the machining quality of the machined surface cut at 16. Therefore, as in the configuration described in the present embodiment, the ratio n / N of the length n of the convex portion 19 along the virtual contour P to the length N of the concave portion 18 along the virtual contour P in the corner blade 17 is Each of the corner blade 17 and the outer peripheral blade 16 is made larger than the ratio m / M of the length m of the convex portion 19 along the virtual contour P to the length M of the concave portion 18 along the virtual contour P in the outer peripheral blade 16. The overlap length of the convex part 19 can be made substantially equal, and the difference in the processing quality of the processed surfaces cut by the corner blade 17 and the outer peripheral blade 16 can be reduced.

Moreover, since the rake angle C of the corner blade 17 is made larger than the rake angle C of the outer peripheral blade 16, the following effects are produced.
That is, since the rake angle C in the outer peripheral blade 16 having a high cutting speed and thick chip is reduced, the cutting edge strength in the outer peripheral blade 16 is ensured, and chipping and chipping are effectively suppressed. It will be. On the other hand, in the corner blade 17 having a cutting load smaller than that of the outer peripheral blade 16, the rake angle C is increased, so that a sharp sharpness can be secured, the cutting resistance is reduced, and the processing quality is enhanced.

Further, since the rake angle C of the corner blade 17 is increased from the outer peripheral blade 16 toward the ramping blade 24 side, the following effects are obtained.
That is, in the corner blade 17, the rake angle C of the corner blade 17 is reduced at the portion on the outer peripheral blade 16 side where the cutting speed is high and the thickness of the chip is thick (that is, the cutting load is large). Is ensured and chipping and chipping are suppressed. On the other hand, in the corner blade 17, the rake angle C of the corner blade 17 is increased at the portion on the ramping blade 24 side where the cutting speed is low and the thickness of the chip is thin (that is, the cutting load is small). Can be ensured, cutting resistance is reduced, and processing quality is improved.

Moreover, in this embodiment, since the recessed part 18 of the cutting blade 15 of cutting insert 1A-1C has comprised the concave curve shape, unlike this embodiment, for example, the recessed part of a cutting edge is bending by the combination of a some straight line. Compared with a case where the entire surface is concave (for example, a rectangular concave), the cutting edge strength is increased and chip clogging is also suppressed.
Moreover, since the convex part 19 which comprises the waveform of the cutting edge 15 with the recessed part 18 and adjoins this recessed part 18 is formed along the virtual contour line P of the cutting edge 15, this convex part 19 is cut. Unevenness is less likely to be formed on the processed surface of the cutting material, and the processed surface quality is improved. Specifically, according to the present embodiment, for example, a machined surface quality close to a cutting mark obtained by cutting a work material with a blade end replaceable radius end mill provided with a cutting insert having a corrugated cutting edge is obtained. be able to.

  Further, in the cutting edge replaceable end mill 10 of the present embodiment, the cutting inserts 1A to 1C are mounted on the insert mounting seats 4A to 4C of the end mill body 2 so that the cutting inserts 1A to 1C have a rotation locus around the axis O. The positions of the concave portion 18 and the convex portion 19 are shifted in the direction along the virtual contour line P, while the virtual contour lines P of the cutting edges 15 are arranged to coincide with each other. Therefore, according to this edge-replaceable end mill 10, the cutting inserts 1 </ b> A to 1 </ b> C can be cut by a simple operation of simply mounting a plurality of types of cutting inserts 1 </ b> A to 1 </ b> C on the insert mounting seats 4 </ b> A to 4 </ b> C of the end mill body 2. The positions of the concave portions 18 and the convex portions 19 of the blade 15 are shifted from each other in the direction along the virtual contour line P (that is, the blade length direction of the cutting blade 15), and the work surface quality of the work material can be improved. . That is, when these cutting inserts 1A to 1C are mounted on the end mill body 2, troublesome work such as adjusting the cutting edge position is unnecessary, and the workability is excellent.

  Moreover, according to the end mill main body 2 of this embodiment, the outer periphery of the end mill main body 2 corresponding to the concave portion 18 and the convex portion 19 of the cutting edge 15 of the cutting inserts 1A to 1C mounted on the insert mounting seats 4A to 4C. Since the groove 7 and the rib 8 are formed on the surface, it is possible to prevent a mounting error when the cutting inserts 1A to 1C are mounted on the insert mounting seats 4A to 4C. That is, the shape of the cutting edge 15 corresponding to the groove 7 and the rib 8 formed on the rear side in the tool rotation direction T of the predetermined insert mounting seat among the plurality of types of cutting inserts 1A to 1C (concave portion 18 and convex portion 19). It is only necessary to select a predetermined cutting insert provided with and insert it into the insert mounting seat, and the mounting operation of the cutting inserts 1A to 1C can be performed easily and accurately.

  Moreover, since the groove | channel 7 and the rib 8 are formed in the end mill main body 2 corresponding to the recessed part 18 and the convex part 19 of the cutting blade 15 of cutting insert 1A-1C, the outer peripheral surface of this end mill main body 2, and a cut material It is possible to improve the rigidity of the end mill body 2 and the seating stability of the cutting inserts 1A to 1C with respect to the insert mounting seats 4A to 4C, while preventing the contact with the processed surface and ensuring the quality of the processed surface.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

For example, in the above-described embodiment, the end mill main body 2 is formed with three chip pockets 3, and the insert mounting seats 4 </ b> A to 4 </ b> C are provided corresponding to the chip pocket 3, and correspondingly. Three types of cutting inserts 1 </ b> A to 1 </ b> C are also provided, but the number and types of the tip pocket 3, the insert mounting seat 4 and the cutting insert 1 are not limited to the above-described embodiment.
Specifically, for example, six tip pockets 3 are formed in the end mill body 2, and three types of insert mounting seats 4 </ b> A to 4 </ b> C are provided in each of the tip pockets 3, and a pair of three types of cutting inserts 1 </ b> A to 1 </ b> C is paired. Alternatively, six types of insert mounting seats 4 may be provided one by one, and six types of cutting inserts 1 may be mounted one by one.

In the above-described embodiment, the cutting inserts 1 </ b> A to 1 </ b> C have been described as having the vertically long plate-like insert body 11. However, the insert body 11 may be plate-shaped and is limited to the above-described vertically long plate shape. is not.
In addition, although the cutting inserts 1A to 1C are provided with a pair of cutting edges 15 in a 180 ° rotational symmetry, the arrangement and number of the cutting edges 15 are not limited to the above-described embodiment.

  Here, cutting inserts 1A to 1C shown in FIG. 9 are modifications of the embodiment described above. In this modification, the rake angle C of the cutting edge 15 is larger than that described in the previous embodiment, and the rake angle C is 0 ° to 25 °. Thus, by setting the rake angle C of the cutting edge 15 large as a whole, the cutting inserts 1 </ b> A to 1 </ b> C having low resistance and excellent sharpness can be obtained.

  In addition, in the range which does not deviate from the meaning of this invention, you may combine each structure (component) demonstrated by embodiment mentioned above and a modified example (note etc.), addition of a structure, omission, replacement, etc. Can be changed. Further, the present invention is not limited by the above-described embodiments, and is limited only by the scope of the claims.

1A, 1B, 1C Cutting insert 2 End mill body 4A, 4B, 4C Insert mounting seat 7 Groove 10 Cutting edge replaceable end mill 11 Insert body 12 Rake face 14 Relief face 15 Cutting edge 16 Peripheral edge 17 Corner blade 18 Recess 19 Protrusion 24 Ramping Blade C Rake angle M Length of concave portion along virtual contour line at outer peripheral edge m Length of convex portion along virtual contour line at outer peripheral blade N Length of concave portion along virtual contour line at corner blade n Virtual contour at corner blade Length of convex part along line O Axis line P Virtual edge of cutting edge T Tool rotation direction

Claims (6)

A cutting insert having a cylindrical shape and detachably attached to the outer periphery of the end of the end mill body rotated around an axis,
It has a plate-like insert body,
One surface facing the thickness direction of the insert body is a rake surface,
The side surface facing the direction intersecting the thickness direction of the insert body is a flank surface,
The intersecting ridge line between the rake face and the flank face is a cutting edge,
The cutting edge is
An outer peripheral blade in which a virtual contour line that is a basic shape of the cutting blade forms a straight line; and
A corner blade that is continuous with the outer peripheral blade, and the virtual contour line forms a convex curve,
A ramping blade connected to the opposite side of the outer peripheral blade of the corner blade,
Look at the rake face in front,
Of the cutting blades, the outer peripheral blade and the corner blade are formed with a recess that is recessed with respect to the virtual contour line,
The concave portion is not formed in the connecting portion with the ramping blade in the corner blade,
The length of the said recessed part along the said virtual contour line in the said corner blade is made smaller than the length of the said recessed part in the said outer peripheral blade along the virtual contour line. The cutting insert according to claim 1,
The outer peripheral edge and the corner blade are formed with a convex portion adjacent to the concave portion, and the convex portion extends along the virtual contour line,
The ratio n / N of the length n of the convex portion along the virtual contour line to the length N of the concave portion along the virtual contour line in the corner blade is such that the ratio of the concave portion along the virtual contour line in the outer peripheral blade. Cutting insert characterized by being made larger than ratio m / M of length m of said convex part along said virtual outline to length M. The cutting insert according to claim 1 or 2,
A cutting insert characterized in that a rake angle of the corner blade is larger than a rake angle of the outer peripheral blade. The cutting insert according to any one of claims 1 to 3,
A cutting insert characterized in that a rake angle of the corner blade is increased from the outer peripheral blade toward the ramping blade. A plurality of insert mounting seats are formed on the outer periphery of the end of the cylindrical end mill main body at intervals around the axis of the end mill main body, and a plurality of types of cutting inserts are detachably mounted on these insert mounting seats. An exchangeable end mill,
As the cutting insert, comprising the cutting insert according to any one of claims 1 to 4,
Of the cutting edges of the cutting insert, the virtual contour line of the outer peripheral blade extends so as to be parallel to the axis of the end mill body, and the virtual contour line of the corner blade is on the tip side of the end mill body. As it goes, it gradually extends inward in the radial direction perpendicular to the axis,
The plurality of types of the cutting inserts are arranged so that the virtual contours of the cutting edges coincide with each other in a rotation locus around the axis, while the positions of the concave portions are shifted in a direction along the virtual contours. A blade-end replaceable end mill. An end mill body used in the blade end replaceable end mill according to claim 5,
A groove extending around the axis is formed on the outer peripheral surface of the end mill body so as to be disposed on the rear side in the tool rotation direction of the insert mounting seat and corresponding to the concave portion of the cutting edge of the cutting insert. End mill body characterized by this.

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