JP6930245B2 - Cutting insert - Google Patents

Description

The present invention relates to a cutting insert that is attached to a cutting edge exchangeable cutting tool or the like to perform lathe processing of a work material. The present application claims priority with respect to Japanese Patent Application No. 2016-127690 filed on June 28, 2016, the contents of which are incorporated herein by reference.

As such a cutting insert, for example, Patent Document 1 proposes a cutting insert in which the nose cutting edge is divided into at least five circular segments for the purpose of improving the smoothness of the machine tool surface. Here, in the cutting insert described in Patent Document 1, the bisector of the nose radius intersects the first segment having the first radius of curvature re, and the second radius of curvature r2 is provided on both sides of the first segment. The second segment having the second segment is joined, and the third segment having the third radius of curvature r3 is joined to the second segment, and the first to third radius of curvature re, r2, and r3 have a relationship of r3> re> r2. have.

Further, in Patent Document 2, for the purpose of obtaining a finished surface having a good surface roughness, a finishing blade (corner blade) that cuts into a work material in advance and a work that follows this finishing blade. It has a super-finishing blade that finishes the material, and the super-finishing blade projects a predetermined amount from the position of the finishing blade in the direction of increasing the cutting amount, and extends from the burnishing portion and the finishing blade to the burnishing portion in the tool feed direction. Proposed cutting inserts are provided with a burr portion and are configured such that the superfinishing blade burnishes the finished surface while removing the machined alteration layer on the surface machined by the finishing blade.

Further, Patent Document 3 also includes a polygonal plate-like body having an upper surface as a rake face, a lower surface as a seating surface, and a side surface as a flank for the purpose of improving the roughness of the finished surface of the work material. A cutting edge is formed on the ridge between the rake face and the flank, and the corner cutting edge and the Sarae blade connected to both ends of the corner cutting edge are formed at the corner where the ridges of the polygonal plate-like body intersect. A cutting insert has been proposed, which is provided with a cross-cutting blade connected to the Sarae blade, and in which an arcuate protruding portion protruding toward the rake face side is formed on the Sarae blade.

Japanese Unexamined Patent Publication No. 2006-224295 Republished WO2007 / 039444 Japanese Unexamined Patent Publication No. 2003-011006

However, in the cutting insert described in Patent Document 1, the nose cutting edge divided into at least five circular segments described above is arranged on one plane as shown in FIG. 1 of Patent Document 1. .. For this reason, for example, when high feed machining is performed, the wiper blade of the third segment, which is separated from the corner blade (first segment), rubs against the work material and causes an increase in cutting resistance, resulting in unstable cutting and an inner diameter. There is a risk of chattering vibration and waviness of the machined surface during machining and outer diameter machining of small-diameter work materials. Such a problem becomes even more remarkable in the cutting insert described in Patent Document 2 in which the super-finishing blade (wiper blade) is configured to burnish, that is, rub the finished surface.

On the other hand, like the cutting insert described in Patent Document 3, a cutting insert having an arcuate projecting portion formed on the sarae blade (wiper blade) toward the rake face side is integrated with a sintering material such as cemented carbide. When manufactured by sintering, it is difficult to polish a general ISO standard cutting insert to form a protrusion. For this reason, it is necessary to form a recess corresponding to the protruding portion in the mold for press-molding the green compact before being sintered into the cutting insert, which requires a dedicated mold and causes an increase in cost. It will be. Further, for example, in a cutting insert in which a cBN sintered body or a diamond sintered body is arranged in a portion from a corner blade to a wiper blade, such a protruding portion cannot be formed.

The present invention has been made under such a background, and it is possible to prevent an increase in cost in a cutting insert provided with a wiper blade, and also in a cutting insert in which a cBN sintered body or a diamond sintered body is arranged. A cutting insert that can be applied, but prevents an increase in cutting resistance due to rubbing against the work material even in high feed machining, and enables stable cutting in inner diameter machining and outer diameter machining of small diameter work materials. Is intended to provide.

In order to solve the above problems and achieve such an object, the present invention has a rake surface on the polygonal surface at the corner portion of the polygonal surface of the polygonal plate-shaped insert body. A corner blade having a convex curved shape is formed in the plan view facing the surface, and the edge portion of the polygonal surface connected to the corner blade is more curved than the corner blade in the plan view facing the rake face. A wiper blade having a convex curved shape with a large radius is formed, and a chamfer honing surface is formed from the corner blade to the wiper blade. The chamfer honing surface has a constant honing angle and the rake. The honing width in the plan view facing the surface gradually increases as the distance from the corner blade increases in the wiper blade, and the maximum honing width in the wiper blade is 0.115 mm or more and 0.180 mm or less, and the polygonal shape. A flank surface is formed on the side surface of the insert body arranged around the surface, and the chamfer honing surface of the wiper blade is opposed to the intersecting ridge line between the chamfer honing surface and the flank surface of the corner blade. In the direction perpendicular to the polygonal plane on which the rake plane is formed, the intersecting ridge line between the surface and the flank surface is opposite to the rake plane in the range of 0.0070 mm or more and 0.0250 mm or less as the distance from the corner blade increases. The insert body is inclined toward the polygonal surface side, and the insert body has a polygonal plate-shaped base metal and a cutting edge tip located at a corner portion of the base metal, and the cutting edge tip has a cutting edge tip. , CBN sintered body, the cutting edge tip has the corner blade and the wiper blade, and a main cutting edge extending from the end of the wiper blade to the side opposite to the corner blade. ..

In the cutting insert configured in this way, the chamfer honing surface formed from the corner blade to the wiper blade has a constant honing angle, but the honing width in the plan view facing the rake face is from the corner blade to the wiper blade. Since it gradually increases as the distance increases, the intersecting ridge line between the chamfer honing surface of the wiper blade and the flank formed on the side surface arranged around the polygonal surface is opposite to the rake surface as the distance from the corner blade increases. It will be inclined toward the polygonal surface side of.

Therefore, when a negative lateral rake angle and a predetermined lateral clearance angle are given to the wiper blade during cutting, the above-mentioned crossing ridge line between the chamfer honing surface and the clearance surface, which are the cutting edges of the convex curved wiper blade, becomes It is on the side opposite to the corner blade rather than the corner blade side, and is separated from the machined surface so as to escape larger. Therefore, it is possible to prevent the wiper blade on the opposite side of the corner blade and its flank from being strongly rubbed against the work material and increasing the cutting resistance, and even in high feed machining, chatter vibration and waviness of the machined surface can be prevented. It is possible to prevent and perform stable cutting.

Further, such a chamfer honing surface and a wiper blade can be formed by polishing a general ISO standard cutting insert. Therefore, even if the insert body is integrally formed of a sintered material such as cemented carbide, a dedicated die is not required, and the manufacturing cost of the cutting insert can be suppressed. Further, even a cutting insert in which a cBN sintered body or a diamond sintered body is arranged in a portion from the corner blade to the wiper blade can be applied.

Here, a flank is formed on the side surface of the insert body arranged around the polygonal surface as described above, but at the intersecting ridge line between the chamfer honing surface and the flank in the corner blade. On the other hand, the intersecting ridge line between the chamfer honing surface and the flank surface of the wiper blade has a range of 0.0250 mm or less as the distance from the corner blade increases in the direction perpendicular to the polygonal surface on which the rake surface is formed. It is desirable that the blade is inclined toward the polygonal surface opposite to the rake surface.

That is, if the inclination of the intersecting ridge line between the chamfer honing surface and the flank surface of this wiper blade is larger than the above range, the cutting edge of the wiper blade is too far from the machined surface on the side opposite to the corner blade, and the wiper blade is used as a wiper blade. There is a risk that the machined surface cannot be finished smoothly. It is more desirable that this range is 0.0196 mm or less.

However, if this inclination is too small and the intersecting ridge line between the chamfer honing surface and the flank surface of the wiper blade is close to parallel to the polygonal surface as the rake face, the above-mentioned effect may not be obtained. There is. For this reason, this crossing ridge is inclined toward the polygonal plane opposite to the rake face within a range of 0.0070 mm or more with respect to the crossing ridge between the chamfer honing surface and the flank at the corner blade. Is desirable.

A convex curved wiper blade is formed by polishing so as to be in contact with the linear main cutting blade in a general ISO standard cutting insert as described above, and further convex to the corner portion so as to be in contact with the wiper blade. When forming a convex curved corner blade such as an arc, the tip of the corner blade on the bisector of the corner portion recedes to the inside of the insert body as compared with that before the polishing process. Therefore, if an attempt is made to imitate a work material by, for example, an NC lathe using such a cutting insert, uncut parts will be generated by the amount that the tip of the corner blade is retracted, so the program of the NC lathe is modified. Must.

Therefore, in such a case, a linear straight blade in contact with the corner blade and the wiper blade may be formed between the corner blade and the wiper blade in a plan view facing the rake face. By interposing a straight blade between the corner blade and the wiper blade, the tip of the corner blade can be positioned at the same position as the ISO standard cutting insert without changing the radius of curvature of the corner blade or wiper blade. Even if the program is not modified in the cutting process in, it is possible to prevent the uncut portion during the copying process.

As described above, according to the present invention, it can be manufactured at low cost without requiring a dedicated mold, and it is also applied to a cutting insert in which a cBN sintered body or a diamond sintered body is arranged. It is possible, and by suppressing the wiper blade from being rubbed against the work material and suppressing the increase in cutting resistance, chattering vibration and waviness of the machined surface can be achieved even in inner diameter machining with high feed and outer diameter machining of small diameter work materials. It is possible to prevent and perform high-precision and stable cutting.

It is a top view which shows one Embodiment of this invention. It is a side view of the arrow line T direction view in FIG. It is a side view of the arrow line U direction view in FIG. It is an enlarged plan view of the corner part in FIG. It is an enlarged side view of the corner part in FIG. FIG. 5 is a cross-sectional view taken along the line VV in FIG. FIG. 6 is a cross-sectional view taken along the line WW in FIG. FIG. 5 is a cross-sectional view taken along the line XX in FIG. FIG. 5 is a cross-sectional view taken along the line YY in FIG. It is a ZZ cross-sectional view in FIG.

1 to 10 show an embodiment of the present invention. In the present embodiment, the insert body 1 is formed in the shape of a polygonal plate, specifically, in the shape of a rhombic flat plate having an acute-angled corner portion at an angle of 80 °, and has two polygonal surfaces (diamond surfaces) 2. It includes four rectangular side surfaces 3 arranged around these polygonal surfaces 2. At the center of the two polygonal surfaces 2, a mounting hole 4 that has a circular cross section centered on the insert center line L passing through the center of these polygonal surfaces 2 and penetrates the insert body 1 is opened. The two polygonal surfaces 2 have a planar shape perpendicular to the insert center line L.

Here, the insert body 1 of the present embodiment is one of the two polygonal surfaces 2 of the base metal 5 formed in the shape of a substantially polygonal plate as described above by a hard material such as cemented carbide. (Upper polygonal surface in FIGS. 2 and 3) A notch portion 5a having an L-shaped cross section is formed in the two acute-angled corner portions C of 2, and the notch portion 5a has a cBN having a hardness higher than that of the base metal 5. A triangular plate-shaped cutting edge tip 6 made of a sintered body or a diamond sintered body is joined by brazing or the like to form a polygonal plate shape (diamond flat plate shape) as shown in FIGS. 1 to 3. ing.

Further, in the present embodiment, the two corner portions C of one polygonal surface 2 to which the cutting edge tip 6 is joined are flush with the polygonal surface 2 on the cutting edge tip 6 of the polygonal surface 2. A corner blade 8 having a rake face 7 and having a convex curved shape such as a convex arc as shown in FIG. 4 is formed facing the rake face 7 in a plan view seen from the insert center line L direction. .. Therefore, the rake face 7 is also made flat perpendicular to the insert center line L. The insert body 1 of the present embodiment basically conforms to ISO13399 (JIS-B4120-1998) except for the periphery of the corner portion C.

Further, on the two edge portions of the one polygonal surface 2 connected to the corner portion C, a rake face 7 is similarly provided on the one polygonal surface 2 so as to be in direct contact with the corner blade 8 in the present embodiment. A wiper blade 9 having a convex curved shape such as a convex arc having a radius of curvature larger than that of the corner blade 8 in a plan view facing the rake surface 7 from the L direction of the insert center line is formed. .. Therefore, of the four side surfaces 3 arranged around the polygonal surface 2, the two side surfaces 3 intersecting the intersecting ridge line portion connected to the corner portion C have a corner blade 8 and a wiper on at least the rake surface 7 side. A flank 10 connected to the blade 9 is formed.

The cutting insert of the present embodiment is basically a negative type cutting insert in which the flank surface 10 extends in a direction orthogonal to the rake face 7, and is from the flank surface 10 of the corner blade 8 and the end of the wiper blade 9. On the side opposite to the corner blade 8, the flank surface 10 extends in the direction orthogonal to the rake face 7 in this way.

Then, chamfer honing is applied from the corner blade 8 formed in the corner portion C to the wiper blades 9 on both sides thereof, and the intersection of these corner blades 8 and the rake surface 7 of the wiper blade 9 with the flank surface 10. A chamfer honing surface 11 is formed on the ridgeline portion. As shown in FIGS. 2, 3 and 5 to 10, the chamfer honing surface 11 has a cross section orthogonal to the corner blade 8 and the wiper blade 9 in a direction in which the chamfer honing surface 11 is parallel to the rake face 7. On the other hand, the honing angle θ is constant.

On the other hand, the honing width of the chamfer honing surface 11, that is, the width in the direction parallel to the rake face 7 of the chamfer honing surface 11 in the cross section orthogonal to the corner blade 8 and the wiper blade 9 (opposing the rake face 7). The width in the plan view seen from the insert center line L direction) is formed so as to gradually increase as the distance from the corner blade 8 increases in the wiper blade 9. Here, in the present embodiment, the honing width W1 in the corner blade 8 shown in FIG. 2 is constant, and as shown in FIGS. 6 to 10, the honing widths W2 to W6 in the wiper blade 9 are the corner blade 8 and the wiper blade. It is formed so as to gradually increase as the distance from the contact point with 9 toward the side opposite to the corner blade 8 increases.

As described above, the honing widths W2 to W6 of the wiper blade 9 gradually increase as the distance from the corner blade 8 increases, so that in the cutting insert having the above configuration in which the honing angle θ is constant, the wiper blade 9 is shown in FIG. The intersecting ridge line E between the chamfer honing surface 11 and the flank surface 10, which is the cutting edge of the blade, faces the polygonal surface 2 side opposite to the polygonal surface 2 on which the rake surface 7 is formed as the distance from the corner blade 8 increases. It will be tilted.

Similarly, when the honing angle θ is constant and the honing widths W2 to W6 gradually increase as they move away from the corner blade 8, the intersecting ridge line F between the chamfer honing surface 11 and the rake surface 7 is also shown in FIG. 1 in the above plan view. And as shown in FIG. 4, as the distance from the corner blade 8 increases, the angle increases from the crossing ridge line E and toward the inside of the polygonal surface 2. The angle α formed by the crossed ridgeline F separated from the crossed ridgeline E with respect to the crossed ridgeline E in the plan view is set to 1 ° in the present embodiment.

However, the amount of increase in the honing width of the wiper blade 9 is small, and accordingly, the polygonal surface 2 in which the intersecting ridge line E between the chamfer honing surface 11 and the flank surface 10 of the wiper blade 9 is opposite to the rake surface 7. The range of inclination toward the side is also 0. The range is 0250 mm or less, more preferably 0.0196 mm or less, for example, 0.0179 mm in the present embodiment.

That is, the depth D1 in the insert center line L direction of the chamfer honing surface 11 from the rake face 7 to the crossing ridge line E at the end of the wiper blade 9 farthest from the corner blade 8 shown in FIG. 10 and the corner shown in FIG. The difference D1-D2 from the depth D2 in the insert center line L direction of the chamfer honing surface 11 from the rake face 7 to the crossing ridge line E of the blade 8 is in the range of 0.0250 mm or less.

The honing angle θ that is constant from the corner blade 8 to the wiper blade 9 is preferably in the range of 14 ° to 26 °, and is 25 ° in the present embodiment. Further, it is desirable that the maximum honing width W6 of the wiper blade 9 is larger than the honing width W1 of the corner blade 8 in the range of 0.115 mm to 0.180 mm. Therefore, it is desirable that the depth D2 of the corner blade 8 is in the range of 0.0274 mm to 0.0732 mm, and the depth D1 of the wiper blade 9 is in the range of 0.0319 mm to 0.0878 mm from the depth D2. Is also desirable to be increased.

Furthermore, although it also depends on the size of the insert body 1, it is desirable that the radius of curvature of the wiper blade 9 is larger than the radius of curvature of the corner blade 8 in the range of 9.5 mm to 10.5 mm. Further, it is desirable that the length of the wiper blade 9 (the length of a straight line connecting the contact point with the corner blade 8 and the end of the wiper blade 9 in the above plan view) is in the range of 0.33 mm to 0.40 mm. , 0.4 mm in this embodiment.

The portion of the wiper blade 9 opposite to the corner blade 8 from the end is a main cutting blade 12 that has a linear shape in the plan view, that is, a straight line with the wiper blade 9 that has a convex curved shape in the plan view. The contact point with the main cutting blade 12 having a shape is the end on the side opposite to the corner blade 8 of the wiper blade 9. As shown in FIG. 1, the chamfer honing surface 11 of the main cutting blade 12 remains at an angle α formed by the crossing ridge line F with the rake face 7 of the wiper blade 9 with respect to the crossing ridge line E in the plan view. It extends to the obtuse-angled corner of the polygonal surface 2. Therefore, as shown in FIGS. 2 and 3, the intersecting ridge line E is also on the side of the polygonal surface 2 opposite to the polygonal surface 2 on which the rake face 7 is formed as the rake face 7 is formed along the main cutting edge 12 as the distance from the corner blade 8 increases. It is inclined and is cut off to the polygonal surface 2 on which the rake face 7 is formed at the corner portion of the obtuse angle.

The cutting insert configured in this way is seated on the insert mounting seat formed in the holder of the cutting edge replaceable cutting tool, and can be attached and detached by a clamp pin, a lever, a clamp screw or the like inserted through the mounting hole 4. It is attached. Then, the rake face 7 is directed so as to face the rotation direction of the rotating work material, the corner blade 8 is directed in the feed direction with respect to the work material, and the corner blade 8 is on the side opposite to the feed direction. The wiper blade 9 extending in the direction of the corner blade 8 is slightly projected in the cutting direction into the work material to provide a negative lateral rake angle and a predetermined lateral clearance angle.

Here, in the cutting insert having the above configuration, the honing angle θ of the chamfer honing surface 11 formed from the corner blade 8 to the wiper blade 9 is constant, and the honing width of the wiper blade 9 gradually increases as the distance from the corner blade 8 increases. ing. Therefore, the intersecting ridge line E between the chamfer honing surface 11 and the flank surface 10 of the wiper blade 9 is inclined toward the polygonal surface 2 side opposite to the rake surface 7 as the distance from the corner blade 8 increases as described above. Will be done.

Therefore, when the wiper blade 9 projecting in the cutting direction into the work material is given the above-mentioned negative lateral rake angle and a predetermined lateral clearance angle, the chamfer becomes the cutting edge of the convex curved wiper blade 9. The intersecting ridge line E between the honing surface 11 and the flank surface 10 is larger than the corner blade 8 side on the opposite side to the corner blade 8 and is provided with a clearance away from the machined surface. Therefore, it is possible to prevent the wiper blade 9 and its flank 10 from being rubbed against the work material to prevent an increase in cutting resistance, and it is possible to prevent chatter vibration and waviness of the machined surface even in high feed machining. It is possible to prevent and perform high-precision and stable cutting.

Further, the chamfer honing surface 11 and the wiper blade 9 can be formed by polishing the above-mentioned ISO standard cutting insert. That is, in the case of the present embodiment, the insert body 1 is formed so as to be an ISO standard cutting insert in a state where the cutting edge tip 6 is joined to the base metal 5 of cemented carbide or the like, and the insert body 1 is described above. The side surface 3 on the corner portion C side is polished to form a relief surface 10 of the wiper blade 9 that is convex toward the corner portion C side, and at the intersection ridge line portion between the two side surfaces 3 on the corner portion C side. After forming the flank 10 of the corner blade 8 in contact with the flank 10 of the wiper blade 9, the chamfer honing surface 11 is formed on the intersecting ridge of the side surface 3 and the polygonal surface 2 having the flank 10 and the rake face 7. It may be formed.

Therefore, even in a cutting insert in which a cutting edge tip 6 made of a cBN sintered body or a diamond sintered body harder than the base metal 5 is arranged from the corner blade 8 to the wiper blade 9 of the corner portion C as in the present embodiment. , The present invention can be applied relatively easily. Moreover, when the cutting edge tip 6 is joined in this way, it is possible to prevent damage to the boundary portion with the base metal 5. Further, even if the entire insert body 1 is a cutting insert formed of a sintered material such as cemented carbide, a special mold is required to mold the green compact to be sintered on the insert body 1. Therefore, the manufacturing cost of the cutting insert can be suppressed.

Further, in the present embodiment, the crossing ridge line E between the chamfer honing surface 11 and the flank surface 10 of the wiper blade 9 is a rake face with respect to the crossing ridge line E between the chamfer honing surface 11 and the flank surface 10 of the corner blade 8. In the direction perpendicular to the polygonal surface 2 on which the 7 is formed, the blade is inclined toward the polygonal surface 2 opposite to the rake face 7 within a range of 0.0250 mm or less as the distance from the corner blade 8 increases. As described above, the machined surface of the work material can be finished with a wiper blade 9 reliably and sufficiently smoothly.

That is, when the intersecting ridge line E between the chamfer honing surface 11 and the flank surface 10 of the wiper blade 9 extends beyond this range to the polygonal surface 2 side opposite to the rake surface 7, the blade edge of the wiper blade 9 is reached. The crossed ridge line E may be too far from the work material, and the wiper blade 9 may not be able to finish the machined surface sufficiently smoothly. It is more desirable that this range is 0.0196 mm or less as described above.

However, if the intersecting ridge line E between the chamfer honing surface 11 and the flank surface 10 of the wiper blade 9 is close to parallel to the polygonal surface 2 on which the rake surface 7 is formed, the above-mentioned effect cannot be obtained. Since there is a risk, this crossed ridge line E has a range of 0.0070 mm or more with respect to the crossed ridge line E between the chamfer honing surface 11 and the flank surface 10 at the corner blade 8 (the difference D1-D2 between the depths D1 and D2 is large. It is desirable that it is inclined toward the polygonal surface 2 side opposite to the rake surface 7 (within a range of 0.0070 mm or more).

By the way, as described above, the flank surface 10 of the wiper blade 9 is formed on the side surface 3 of the general ISO standard cutting insert, and the corner blade 8 is flanked so as to be in contact with the flank surface 10 of the wiper blade 9. When the chamfer honing surface 11 is formed after the surface 10 is formed on the intersecting ridges of the two side surfaces 3, the tip of the corner blade 8 in the angle bisector direction of the corner portion C in the above plan view is polished. It will be located inside the insert body 1 when no processing is performed. For this reason, if an attempt is made to perform copying with such a cutting insert using, for example, an NC lathe, uncut parts will be generated by the amount that the tip of the corner blade 8 is retracted, so the program of the NC lathe must be modified. It must be as described above.

Therefore, in such a case, the flank surface 10 of the wiper blade 9 is formed by polishing on the two side surfaces 3 intersecting the corner portion C so as to be convex, and then comes into contact with the convex flank surface 10. The flat flank surface 10 is formed by polishing toward the tip of the corner blade 8, and the flank 10 of the corner blade 8 is formed so as to be in contact with the flat flank 10, and the position of the tip is ISO standard. By forming the chamfer honing surface 11 by polishing so that it is the same as the flank surface of the corner blade of the cutting insert, the rake surface 7 is formed between the corner blade 8 and the wiper blade 9. A straight straight blade that is in contact with the corner blade 8 and the wiper blade 9 may be formed in a plane view facing each other.

By forming a straight blade between the corner blade 8 and the wiper blade 9 in this way, the corner blade 8 can be moved in the bisector direction of the corner portion C without changing the radius of curvature of the corner blade 8 and the wiper blade 9. It can be projected to the outside of the insert body 1 so that the tip thereof is at the same position as the ISO standard cutting insert. Therefore, even if the program is not modified in the cutting process on the NC lathe, it is possible to prevent the uncut portion during the copying process.

In the present embodiment, the honing width W1 in the corner blade 8 is constant, but the honing width gradually increases from the tip of the corner blade 8 located on the bisector of the corner portion C toward the wiper blade 9. Alternatively, the honing width may be gradually increased from the middle of the corner blade 8 toward the wiper blade 9.

Next, with respect to the crossing ridge line E between the chamfer honing surface 11 and the flank surface 10 on the corner blade 8, the rake face 7 is formed on the crossing ridge line E between the chamfer honing surface 11 and the flank surface 10 on the wiper blade 9. The range formed in the direction perpendicular to the polygonal surface 2 formed, that is, the depth D1 in the insert center line L direction of the chamfer honing surface 11 from the rake surface 7 to the crossing ridge line E at the end of the wiper blade 9, and the corner blade 8. The effect of the difference D1-D2 from the depth D2 of the chamfer honing surface 11 from the rake face 7 to the crossing ridge line E in the L direction of the insert center line will be demonstrated by giving an example.

In this embodiment, the honing angle θ is in the range of 14 ° to 26 °, the honing width W6 that is the maximum in the wiper blade 9 is in the range of 0.115 mm to 0.180 mm, and the crossing ridge line from the rake face 7 at the end of the wiper blade 9. The depth D1 of the chamfer honing surface 11 up to E in the L direction is in the range of 0.0319 mm to 0.0878 mm, and the insert center of the chamfer honing surface 11 from the rake face 7 to the crossing ridge line E at the corner blade 8. Manufactures 6 types of cutting inserts in which the depth D2 in the line L direction is in the range of 0.0274 mm to 0.0732 mm and the difference D1-D2 between these depths D1 and D2 is 0.0070 mm to 0.0250 mm. bottom. Taking these as Examples 1 to 6, the depths D1 and D2, and the difference D1-D2 and the honing width W6 are shown in Table 1.

Further, as a comparative example with respect to Examples 1 to 6, the depth D1 and the depth D2 are equal and the difference D1-D2 is 0, that is, the intersection of the chamfer honing surface 11 and the flank surface 10 in the wiper blade 9. As the ridge line E moves away from the corner blade 8, it is not inclined so as to face the polygonal surface 2 opposite to the rake surface 7, and although it is inclined, the inclination is small and the difference D1-D2 is 0.0070 mm. Less than, conversely, the inclination is large and the difference D1-D2 exceeds 0.0250 mm, and the depth D1 is larger than 0.0878 mm and the depth D2 is also larger than 0.0732 mm and the difference D1-D2 is 0. Four types of cutting inserts, which exceed .0250 mm, were also manufactured. These are shown in order as Comparative Examples 1 to 4, and the depths D1 and D2, and the difference D1-D2 and the honing width W6 are also shown in Table 1.

The cutting inserts of Examples 1 to 6 and Comparative Examples 1 to 4 are basically of the CNGA120408 type in ISO13399 (JIS-B4120-1998) except for the periphery of the corner portion C. Further, the honing angle θ is calculated from the honing width W6 and the depth D1, but in Examples 1 to 6, they are 14 °, 15 °, 15 °, 25 °, 26 °, and 26 °, respectively, and Comparative Examples 1 to 6. In 4, it is 25 °, 15 °, 25 °, and 35 °, respectively. Further, a cBN sintered body was used as the cutting edge tip 6.

Then, by using the cutting inserts of Examples 1 to 6 and Comparative Examples 1 to 4, continuous turning of the outer diameter is performed on a cylindrical work material having a diameter of 30 mm and a length of 100 mm made of SCr420 (hardness 60HRc), and the cutting speed. The life of the cutting insert was determined by dry machining under the conditions of Vc: 160 m / min, feed amount fr: 0.2 mm / rev per rotation of the work material, and depth of cut ap: 0.15 mm. In the determination, the life was defined as the cutting length (km) when the surface roughness Rz (maximum height roughness in JIS-B0601-2001) of the work material became 6.3 μm or more. Table 1 also shows the cutting length at the time of reaching this life.

From the results in Table 1, first, the intersecting ridge line E between the chamfer honing surface 11 and the flank surface 10 of the wiper blade 9 is inclined toward the polygonal surface 2 side opposite to the rake surface 7 as the distance from the corner blade 8 increases. In Comparative Example 1 in which the blade is not tilted and Comparative Example 2 in which the tilt is small but the difference D1-D2 is less than 0.0070 mm, chatter vibration occurs and the cutting length is determined to be less than 10 km. rice field. On the contrary, in Comparative Example 3 in which the inclination is large, the smoothing effect (wiper effect) of the machined surface by the wiper blade 9 is small, and the surface roughness Rz of the work material is also large with a short cutting length. Further, even in Comparative Example 4 in which the depths D1 and D2 and the difference D1-D2 thereof are larger than the above range and the honing angle θ also exceeds 26 °, chatter vibration occurs, and the life is reached with the shortest cutting length. ..

In contrast to the cutting inserts of Comparative Examples 1 to 4, the cutting inserts of Examples 1 to 6 do not cause chattering vibration, etc., and can obtain a cutting length of 10 km or more, and are highly accurate and stable. It was possible to carry out the cutting process over a long period of time. In particular, in Examples 1 to 4 and Example 6 in which the difference D1-D2 is in the range of 0.0196 mm or less, a cutting length exceeding 10 km is obtained until the service life. From this result, it can be seen that the difference D1-D2 is preferably in the range of 0.0196 mm or less, more preferably in the range of 0.0196 mm or less, and further preferably in the range of 0.0070 mm or more. ..

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the embodiment of the regulations. Configurations can be added, omitted, replaced, and other modifications without departing from the spirit of the present invention. The present invention is not limited by the above description, but only by the appended claims.

The present invention relates to a cutting insert that is attached to a cutting edge exchangeable cutting tool or the like to perform lathe processing of a work material. According to the cutting insert of the present invention, the corner portion of the polygonal surface of the polygonal plate-shaped insert body has a rake face on the polygonal surface and forms a convex curve in a plan view facing the rake face. A corner blade is formed, and a wiper blade having a convex curve shape having a radius of curvature larger than that of the corner blade is formed in a plan view facing the rake face at the edge of the polygonal surface connected to the corner blade. A chamfer honing surface is formed from the corner blade to the wiper blade. The chamfer honing surface has a constant honing angle, and the honing width in a plan view facing the rake surface is the wiper. Since the blade gradually increases in size as it moves away from the corner blade, it can be manufactured at low cost without the need for a dedicated mold, and it can also be used for cutting inserts in which a cBN sintered body or a diamond sintered body is arranged. It is applicable, and by suppressing the wiper blade from being rubbed against the work material and suppressing the increase in cutting resistance, chatter vibration and waviness of the machined surface even in inner diameter machining with high feed and outer diameter machining of small diameter work materials. It is possible to perform high-precision and stable cutting.

1 Insert body 2 Polygonal surface 3 Side surface 7 Scoop surface 8 Corner blade 9 Wiper blade 10 Chamfer surface 11 Chamfer honing surface L Insert center line C Corner part E Chamfer honing surface 11 and escape surface 10 crossing ridge line F Chamfer Intersection ridge line between honing surface 11 and rake surface 7 D1 Depth of chamfer honing surface 11 from rake surface 7 at the end of wiper blade 9 to intersection ridge line E in the insert center line L direction D2 From rake surface 7 at corner blade 8 Depth of the chamfer honing surface 11 up to the crossing ridge E in the L direction of the insert center line W1 to W6 Honing width θ Honing angle

Claims (3)

At the corner portion of the polygonal surface of the polygonal plate-shaped insert body, a corner blade having a rake face on the polygonal surface and forming a convex curved shape in a plan view facing the rake face is formed, and the corner blade is formed. At the edge of the polygonal surface connected to the corner blade, a wiper blade having a convex curved shape having a radius of curvature larger than that of the corner blade is formed in a plan view facing the rake surface. A chamfer honing surface is formed on the wiper blade, and the chamfer honing surface has a constant honing angle, and the honing width in a plan view facing the rake surface gradually increases as the wiper blade moves away from the corner blade. Get bigger,
The maximum honing width of the wiper blade is 0.115 mm or more and 0.180 mm or less.
A flank is formed on the side surface of the insert body arranged around the polygonal surface, and the chamfer in the corner blade is opposed to the crossing ridgeline between the chamfer honing surface and the flank. In the direction perpendicular to the polygonal surface on which the rake surface is formed, the intersecting ridge line between the fur honing surface and the flank surface is in the range of 0.0070 mm or more and 0.0250 mm or less as the distance from the corner blade increases. Is inclined toward the opposite polygonal surface side ,
The insert body has a polygonal plate-shaped base metal and a cutting edge tip located at a corner portion of the base metal. The cutting edge tip is made of a cBN sintered body, and the cutting edge tip is made of a cBN sintered body. , The corner blade and the wiper blade, and a main cutting blade extending from the end of the wiper blade to the side opposite to the corner blade .
A cutting insert characterized by that. A flank is formed on the side surface of the insert body arranged around the polygonal surface, and the chamfer in the corner blade is opposed to the crossing ridgeline between the chamfer honing surface and the flank. In the direction perpendicular to the polygonal surface on which the rake surface is formed, the intersecting ridge line between the fur honing surface and the flank surface is 0.0196 mm or less as the distance from the corner blade increases, which is opposite to the rake surface. The cutting insert according to claim 1 , wherein the cutting insert is inclined toward the polygonal surface side. Claim 1 or the above-described 1 or The cutting insert according to 2.

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