JP4671643B2 - Milling tools - Google Patents

Description

  The present invention relates to a milling tool that is used with a cutting insert attached to the tip of a holder.

  In recent years, demands for high precision and high efficiency of milling tools have increased, and various shapes of cutting inserts used for them have been developed and used in various fields such as die machining.

  For example, Patent Document 1 describes a cutting insert having a substantially parallelogram plate shape and having a corrugated cutting edge on the crossing ridge line between the upper surface forming the rake face and the side surface forming the flank face.

Here, the flank in the cutting insert becomes a holder constraining surface having a complicated shape in which the thickness direction is curved and the longitudinal direction is twisted spirally from the wavy main flank through the stepped flank. It consists of a second flank. Furthermore, the substantial clearance angle of the outer peripheral cutting edge when mounted on the holder and the angle formed by the rake face of the cutting insert and the main clearance surface are constant from the front end portion to the rear end portion. It is described that processing can be performed with high accuracy.
JP-A-11-333616

  However, with the cutting insert of Patent Document 1, when machining with a large vertical depth of cut, the sharpness of the entire cutting blade decreases, so that the cutting resistance increases, and the impact is first caused by collision with the work material. There was a problem that defects occurred at the large tip, burrs occurred on the machined surface, and boundary damage occurred near the portion corresponding to the rear end of the outer peripheral cutting blade used for cutting. .

  In addition, when the sharpness is deteriorated in this way, the load applied to the cutting insert increases. However, as in Patent Document 1, if the flank has a complicated shape spirally twisted, the constraining surface that comes into contact with the holder is reduced. Since it is a curved surface, there is a problem that surface accuracy is lowered, stable restraining force cannot be obtained, chatter vibration is generated, high-quality cutting cannot be performed, and defects and boundary damage are more likely to occur.

  Furthermore, the complicated flank shape has a problem in that it takes time to manufacture in production and accuracy control is not easy and a stable milling tool cannot be supplied.

  The present invention is for solving the above-mentioned problems, and can provide a milling tool including a cutting insert that can reduce chipping, boundary chipping, and burr generation, and that can be easily manufactured and can perform high-precision cutting. The purpose is to provide.

  According to the present invention, at the time of cutting, the substantial clearance angle at the front end portion of the outer peripheral cutting edge that is first contacted with the work material and receives a large impact and is likely to be damaged is reduced, and after the outer peripheral cutting edge. Since the substantial clearance angle at the end can be increased, and the cutting insert can be manufactured easily and accurately, and the restraining force on the holder can be stably increased, so that there is no defect at the tip of the outer peripheral cutting edge. In particular, the sharpness is not extremely deteriorated, and the cutting can be performed stably with high accuracy without occurrence of chipping or boundary damage under a wide range of cutting conditions.

That is, the milling tool of the present invention is a milling tool in which at least one cutting insert is mounted on the tip of a holder, wherein the cutting insert has a polygonal shape as a basic shape, a bottom surface that forms a seating surface, and a rake surface. An upper surface, a side surface that forms a flank surface, an outer peripheral cutting edge that is formed on a cross ridge line portion between the rake surface and the flank surface, and is positioned on the outer periphery of the holder; A corner cutting edge connected to the blade, and a flank that continues from the outer peripheral cutting edge is a first flank adjacent to the outer peripheral cutting edge, and a first flank located closer to the bottom side than the first flank. a secondary flank consists, the second flank is divided into three sections, in the said corner cutting edge side, a second flank located on the distal end portion of the outer peripheral cutting edge, the corner cutting edge there on the side away from, the A second flank located on the rear end portion of the peripheral cutting edge, consists of a second flank located on the central portion between the tip and the rear end portion of the outer peripheral cutting edge, the second flank A surface is adjacent to the first flank at the positions of the front end, the center, and the rear end of the outer peripheral cutting edge, and a second flank located at the front end of the outer peripheral cutting edge; The second flank located at the rear end of the outer peripheral cutting edge is located on the same plane, and the flank angle of the first flank at the tip of the outer peripheral cutting edge is the flank angle of the second flank. to small and at the rear end of the outer peripheral cutting edge, wherein the clearance angle of the first flank is greater with respect to the relief angle of the second flank.

Here, the outer peripheral cutting edge is located on the corner cutting edge side, the height position from the bottom surface is the same at the front end flat section , and at the rear end of the front end flat section, and from the front end to the rear end. The cutting edge strength at the tip of the outer peripheral cutting edge is provided with an inclined section whose height gradually decreases toward the rear end of the inclined section and a rear end flat section having the same height position from the bottom surface. In addition, it is possible to prevent the cutting resistance from increasing at the center toward the rear end of the outer peripheral cutting edge, and to secure the necessary strength when handling the cutting insert at the rear end of the outer peripheral cutting edge and to escape. It is desirable in that the generation of defects and boundary damage can be suppressed by securing a constrained area to the holder of the surface and further reducing the cutting resistance by tightening the inclination angle at the central portion of the outer peripheral cutting edge.

  Furthermore, the second flank located in the middle of the outer peripheral cutting edge is formed in the same plane as the first flank located above the second flank, so that the insert shape can be made with high accuracy. This is desirable because it can be easily manufactured. The central part of this outer peripheral cutting edge is the part where deformation during molding and firing is the largest, and by simplifying the shape of this part, the uniformity of powder filling during molding is improved, and deformation during firing There is also an effect that can be reduced.

  The above-described milling tool of the present invention reduces the substantial clearance angle at the time of mounting the main body at the tip of the outer peripheral cutting edge, which is likely to be damaged due to a large impact when it first comes into contact with the work material in the cutting process. A substantial clearance angle at the blade rear end can be increased, and a cutting insert having a shape with a strong restraining force can be easily manufactured, and the restraining force on the holder can be stably increased. As a result, there is no chipping at the tip of the outer peripheral cutting edge, and particularly good cutting can be performed without causing any boundary damage, without sharply deteriorating sharpness under cutting conditions in which a large vertical cut is made. .

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 to 7 show an example of an embodiment of a milling tool of the present invention (hereinafter abbreviated as a tool). FIG. 1 is an overall perspective view of the tool of the present invention, and FIG. FIG. 3 is a top view of the insert of FIG. 2, FIG. 4 is a side view of the insert of FIG. 2 as viewed from the X direction, and FIG. 5 is FIG. (A) AA cross-section, (b) BB cross-section, (c) Cross-sectional view showing CC cross-section, FIG. 6 is (a) cutting the outer periphery when the insert is attached to the holder of FIG. FIG. 7 is a cross-sectional view at the blade tip, (b) a cross-sectional view at the rear end of the outer peripheral cutting blade, and FIG. 7 is an enlarged view of the tip of the holder unit in FIG.

  In FIG. 1, a tool 1 is formed by mounting at least one insert 3 on the tip of a substantially cylindrical holder 2, and the holder 2 rotates around the central axis of the holder 2 to perform cutting work on the insert 3. Is to do. According to FIG. 1, insert pockets 4 are formed at three positions on the tip of the holder 2, and the inserts 3 are fitted into the respective insert pockets 4 and fixed to the holder 2 with fixing screws 6.

  On the other hand, the insert 3 has a parallelogram shape as a basic shape, and has a seating surface 8 on the bottom surface, a rake surface 9 on the top surface, a flank surface 10 on the side surface, and a long side at the intersection ridge between the rake surface 9 and the flank surface 10 An outer peripheral cutting edge 12 that is formed on the outer periphery of the holder 2 and a corner cutting edge 14 that extends from the outer peripheral cutting edge 12 to the tip end portion are provided at two opposite corners. Furthermore, in the insert 3 of the present embodiment, a bottom cutting edge 15 is formed on the short side portion following the corner cutting edge 14, and the outer peripheral cutting edge 12 and the bottom cutting edge 15 are substantially perpendicular. With this configuration, it is possible to perform cutting with high processing accuracy in shoulder processing in which the processing bottom surface of the work material and the processing side wall surface perpendicular thereto are simultaneously cut. The radius of curvature of the corner cutting edge 14 is 0.4 to 6.4 mm from the balance between the cutting edge strength and the processed shape.

  Further, the flank 10A continuing from the outer peripheral cutting edge 12 includes a first flank 17 adjacent to the outer peripheral cutting edge 12 and a second flank 18 positioned on the seating surface side from the first flank 17; The flank 18 is divided into at least three sections (20, 21, 22), the second flank 20 located at the tip of the outer peripheral cutting edge 12, and the second flank located at the rear end of the outer peripheral cutting edge 12. The surface 22 is located on the same surface, and both (20, 22) are constraining surfaces when the holder 2 is mounted.

Further, as shown in FIG. 5, the relationship between the first flank 17 and the second flank 18 is such that the flank angle _βf1 of the first flank 17 is the flank of the second flank at the tip on the corner cutting edge 14 side. At the rear end that is set smaller than the angle β _f2 and moves away from the corner cutting edge 14, the clearance angle β _r1 of the first flank is set larger than the clearance angle β _r2 of the second flank. With the above configuration, as shown in FIG. 6, the substantial clearance angle β ′ _f at the time of attaching the holder at the front end of the outer peripheral cutting edge 12 that is subject to cutting and is likely to be damaged is reduced, and after the outer peripheral cutting edge 12. Since the substantial clearance angle β ′ _r at the end portion can be increased to improve the sharpness, and the insert 3 can be easily manufactured and the restraining force on the holder 2 can be increased with high accuracy, the outer peripheral cutting edge 12 Good cutting can be performed without causing any defects at the tip, particularly under cutting conditions in which a large longitudinal cut is made, and the sharpness becomes extremely poor and no boundary damage occurs.

Here, the substantial clearance angle β ′ _f at the front end portion of the outer peripheral cutting edge 12 is formed to be 5 to 10 ° smaller than the substantial clearance angle β ′ _{r at the} rear end portion of the outer peripheral cutting edge 12. However, it is desirable in that the effect of enhancing the sharpness while maintaining the cutting edge strength is remarkable.

  In addition, the second flank 20 located at the front end of the outer peripheral cutting edge 12 and the second flank 22 located at the rear end of the outer peripheral cutting edge 12 are located on the same plane, and (20, 22) Since this also serves as a restraining surface when mounted on the holder 2, as shown in FIG. 7, the lateral contact surface 25 of the insert pocket 4 of the holder 2 that is in contact with the second flank surfaces 20 and 22 is a simple flat surface. In addition, since the second flank surfaces 20 and 22 have a reference, the processing accuracy is increased, the mounting accuracy is high, and a strong restraining force can be obtained. In addition, the tool 1 can be easily manufactured with high accuracy and can provide a stable quality tool 1.

  The second flank 21 positioned at the center of the outer peripheral cutting edge 12 is accommodated in a notch 26 formed in the lateral contact surface 25 of the insert pocket 4. Further, the first flank 17 is also in a state where the outer peripheral cutting edge 9 a that is housed in the escaping portion 28 formed at the upper portion of the lateral contact surface 25 of the insert pocket 4 and does not participate in cutting does not contact the holder 2. Yes.

  In the insert 3 of the present invention, the rake angle α from the outer peripheral cutting edge 12 toward the rake face 9 is constant for the insert 3 alone from the front end portion to the rear end portion of the outer peripheral cutting edge 12, as shown in FIG. Further, the outer peripheral cutting edge 12 is formed with a boundary portion 30 between the land portion and the honing portion in order to prevent breakage.

  Here, as shown in FIG. 4, the outer peripheral cutting edge 12 has a tip flat section 12A having the same height on the corner cutting edge 14 side, and an inclined section in which the height gradually decreases from the front end to the rear end at the rear end portion. 12B and the rear end flat section 12C having the same height at the center of the rear end can increase the cutting edge strength at the front end of the outer peripheral cutting edge 12 and at the rear end of the outer peripheral cutting edge 12. It is possible to prevent the cutting force from increasing at the center portion toward which it goes, and to secure the necessary strength when handling the insert 3 at the rear end portion of the outer peripheral cutting edge 12 and to secure a constraining area to the holder of the flank 10A. In addition, it is desirable in that generation of defects, boundary damage, burrs, and the like can be suppressed by further reducing the cutting resistance by tightening the inclination angle at the center of the outer peripheral cutting edge 12.

  Furthermore, it is desirable that the second flank 18 located in the middle of the outer peripheral cutting edge 12 is formed in the same plane as the first flank 17 in that the shape of the insert 3 can be easily manufactured with high accuracy. The central portion of the outer peripheral cutting edge 12 is the portion where deformation during molding and firing is the largest, and by simplifying the shape of this portion, the uniformity of powder filling during molding is improved, and during firing, There is also an effect that deformation can be reduced.

That is, according to FIG. 5, for the insert 3, the angle K _f <180 ° between the first flank 17 and the second flank 18 ( 20 ) at the tip of the corner cutting edge 14, and the first at the center. An angle K _c = 180 ° formed by the first flank 17 and the second flank 18 ( 21 ), and at the rear end of the corner cutting edge 14, the first flank 17 and the second flank 18 ( 22 ) The formed angle K _r > 180 °.

  Here, according to the insert 3 of the present invention, as shown in FIG. 3, the central portion of the outer peripheral cutting edge 12 has a shape that swells in the outer peripheral direction when viewed from above, and is attached to the holder 2 and rotated. The trajectory of the outer peripheral cutting edge 12 is configured to form a cylinder. Accordingly, the first flank 17 and the second flank 18 are formed on the same surface in the flank 10A following the central portion of the outer peripheral cutting edge 12 as described above, thereby making the shape of the insert 3 more complicated. Avoiding this leads to easy and stable manufacturing.

  In addition, as shown in FIG. 2, the chip breaker is formed so as to have a raised portion 31 after being lowered from the corner cutting edge 14 and the outer peripheral cutting edge 12 toward the center in the longitudinal direction of the rake face 9, The design is such that the chips are curled or divided and discharged well.

Here, according to the present invention, like the insert 3 , the second flank 18 is divided into three parts (20, 21, 22) at the front end part, the central part, and the rear end part (20, 21, 22). How to design only the second flank 22 located on the second flank 20 and the rear end portion of which a same plane, manufacture, Ru enhanced dimensional accuracy of the constraining surface (flatness).

  Furthermore, although the bottom surface 8 is a flat surface in FIG. 4, the present invention is not limited to this. For example, so-called serrations, which are elongated and unevenly arranged in parallel with each other, are repeated to form a longitudinal section or a transverse section. A wavy configuration may be used.

  Moreover, although the insert 3 provided with the bottom cutting edge 15 was illustrated as a present Example, this invention is not limited to this, For example, in the rear-end part of the insert 3 of the holder 2 of FIG. The present invention can also be applied to an insert without a bottom cutting edge additionally provided in a so-called helical type milling tool additionally provided with an insert.

It is a schematic perspective view which shows an example of the milling tool of this invention. It is a schematic perspective view of the cutting insert with which the milling tool of FIG. 1 is mounted. It is a top view of the cutting insert of FIG. It is the side view which looked at the cutting insert of FIG. 2 from the X direction. It is a schematic sectional drawing which shows the (a) AA cross section of the cutting insert of FIG. 4, (b) BB cross section, (c) CC cross section. It is sectional drawing in the (a) outer periphery cutting blade front-end | tip part at the time of insert mounting | wearing to the holder of FIG. It is the front-end | tip enlarged view of the holder single-piece | unit of Fig.1 (a).

Explanation of symbols

1 Milling tool (tool)
2 Holder 3 Cutting insert (insert)
4 Insert pocket 5 Screw hole 6 Fixing screw 8 Seating surface (bottom surface)
9 Rake face (upper surface)
10 Flank (side)
10A The flank 12 that continues from the outer peripheral cutting edge 12 The outer peripheral cutting edge 12A The tip flat section 12B The inclined section 12C The rear end flat section 14 The corner cutting edge 15 The bottom cutting edge 17 The first flank 18 The second flank 20 At the tip of the outer peripheral cutting edge The second flank face 21 The second flank face located at the center of the outer peripheral cutting edge 22 The second flank face 25 located at the rear end of the outer peripheral cutting edge 25 The laterally constraining face 26 of the insert pocket The notch 28 of the insert pocket Relief part 30 Boundary part 31 Raised part

Claims (3)

In a milling tool formed by attaching at least one cutting insert to the tip of the holder,
The holder is formed on a polygonal shape as a basic shape at a bottom surface forming a seating surface, a top surface forming a rake surface, a side surface forming a flank surface, and a cross ridge line portion between the rake surface and the flank surface. An outer peripheral cutting edge located on the outer periphery of the cutting insert, and a corner cutting edge connected to the outer peripheral cutting edge at a corner of the cutting insert,
The flank that continues from the outer peripheral cutting edge consists of a first flank adjacent to the outer peripheral cutting edge, and a second flank located on the bottom side of the first flank,
The second flank is divided into three sections, on the corner cutting edge side , on the side of the second flank located at the tip of the outer peripheral cutting edge and away from the corner cutting edge , The second flank located at the rear end of the outer peripheral cutting edge, and the second flank located at the center between the tip and rear end of the outer peripheral cutting edge,
The second flank is adjacent to the first flank at the positions of the front end, the center, and the rear end of the outer peripheral cutting edge,
While the second flank located at the tip of the outer peripheral cutting edge and the second flank located at the rear end of the outer peripheral cutting edge are located on the same plane,
Wherein in the distal portion of the peripheral cutting edge small relief angle of the first flank to the second flank relief angle, and the rear end portion of the outer peripheral cutting edge is the relief angle of the first flank the first two flank face milling tool has the size to the clearance angle. The outer peripheral cutting edge is located on the corner cutting edge side, is located at the tip flat section having the same height position from the bottom surface, and is located at the rear end of the tip flat section , and increases from the tip toward the rear end. 2. The milling tool according to claim 1, further comprising an inclined section that gradually decreases, and a rear end flat section that is located at a rear end of the inclined section and has the same height position from the bottom surface . Second flank located in the center portion of the outer peripheral cutting edge, the angle between the first flank located on top of said second flank is 180 degrees, according to claim 1 or 2 Tool according .

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