JP4920171B2 - Method for manufacturing throwaway chip and press molding die for green compact used in the manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a so-called vertical blade type throw-away tip in which a rake face is formed on a peripheral surface arranged around a flat plate surface facing a thickness direction of a chip body having a substantially flat plate shape, and the like. The present invention relates to a green compact press-molding die used in the production method in the case of producing a throw-away tip from a green compact obtained by compressing the raw material powder.

  As a manufacturing method of such a vertical blade type throwaway tip and a press molding die of a green compact used in the manufacturing method, for example, Patent Document 1 discloses a rectangular flat plate-shaped chip body 1 as shown in FIG. A pair of peripheral surfaces located on opposite sides of the four peripheral surfaces arranged around the flat plate surface 2 forming the rectangular shape are rake surfaces 3, and the rake surfaces 3 and flank surfaces are used. In order to manufacture a throw-away tip having an intersecting ridge line with the flat plate surface 2 as a cutting edge 4, they face each other in a direction perpendicular to a direction corresponding to the thickness direction of the tip body 1 (vertical direction in FIG. 14). The upper and lower punches that are separated from each other (moving up and down), and the die that is disposed so as to surround the upper and lower punches that are moved up and down and define a cavity between the upper and lower punches. Press mold There are a raw material powder of the throw-away tip of cemented carbide or the like were charged into the cavity, which press-formed green compact by compression is proposed by the upper and lower punches.

  In the throw-away tip, the crossed ridge line between the other peripheral surface 5 adjacent to the rake face 3 of the peripheral surface of the tip body 1 and the rake face 3 is also used as the cutting edge 6. In this case, the other peripheral surface 5 is a flank of the cutting edge 6. Then, corner portions 7 connected to the cutting edges 4 and 6 are formed at corners of the rake face 3 where the intersecting ridgelines where the cutting edges 4 and 6 are formed intersect with each other, and the flat plate connected to the corner portions is formed. An intersection ridge line portion between the surface 2 and the other peripheral surface 5 is a corner ridge line portion 8. Here, the corner ridge line portion 8 is a convex curved surface that is curved in a convex arc shape in section from the other peripheral surface 5 to the flat plate surface 2, that is, a ¼ convex cylindrical surface. Also, it has a ¼ convex arc shape smoothly connected to the cutting edges 4 and 6.

  Further, in this throw-away tip, the rake face 3 and the flat plate surface 2 serving as a flank, the other peripheral surface 5, and the corner ridge line portion 8 are orthogonal to each other via the cutting edges 4 and 6 and the corner portion 7. It is a negative type throw-away tip arranged in the direction. Further, in Patent Document 1, a pin is provided in the cavity so that the pin can be projected and retracted, and a through-hole serving as a mounting hole 9 into which a clamp screw or the like is inserted when the throw-away tip is attached to the tool body is provided. It is designed to form a green compact.

On the other hand, Patent Document 2 discloses a method for manufacturing a throw-away tip and a dust compact thereof, in which a rectangular flat plate surface facing the thickness direction of a rectangular flat plate-shaped chip body is used as a rake face, unlike the above-described vertical blade type throw-away tip. As a body press-molding die, a press-molding die provided with an up-and-down punch that moves up and down in a direction corresponding to the thickness direction of the chip body and a die that surrounds the periphery and defines a cavity is used. The portion near the flat plate surface opposite to the rake face of the peripheral surface of the chip body (around the throw-away chip described in Patent Document 2) disposed around the flat plate surface is the time of the green compact. When chamfering, the edge of the lower punch that forms this part of the green compact is provided with an edge, and the tip of this edge is chamfered with a flat surface so that the tip of the edge is broken, such as chipping. It has been proposed to prevent the results. The green compact molded by these press molds is sintered and manufactured to the above-mentioned throw-away tip.
Japanese Patent Laid-Open No. 10-146695 JP 2002-210603 A

  However, as described in Patent Document 1, the green compact formed on the vertical blade type throw-away tip moves up and down facing each other in a direction perpendicular to the direction corresponding to the thickness direction of the tip body 1. If the upper and lower punches are used for press molding, the size of the green compact in the direction of compression becomes larger than the thickness of the green compact, which may make it difficult to uniformly compress the raw material powder. It was. In particular, in the manufacturing method and press molding die described in Patent Document 1, the mounting hole 9 that penetrates the chip body 1 in the thickness direction is formed, and therefore the direction corresponding to the thickness direction, that is, compression by the upper and lower punches. A pin is provided in a direction perpendicular to the direction so that it can protrude into and out of the cavity, and when the raw material powder is compressed, the compression ratio changes slightly around this pin. A minute deformation occurs around the hole 9.

  On the other hand, for example, as shown in FIG. 15, the green compact of such a vertical blade type throwaway tip is arranged in a direction corresponding to the thickness direction of the tip body 1 (up and down in FIG. 15). If a press molding die having upper and lower punches 11 and 12 facing and separating from each other and a die 14 surrounding the periphery and defining the cavity 13 is to be molded, Since the protruding pin 15 extends in the compression direction by the upper and lower punches 11 and 12, deformation due to a change in the compression ratio around the pin 15 can be suppressed, but the cross-section of the chip body 1 in the green compact has a ¼ convex arc shape. The peripheral portions of the press surfaces 16 and 17 of the upper and lower punches 11 and 12 that form the portion corresponding to the corner ridge line portion 8 are formed into a concave arc shape of ¼ as shown in FIG. As a result, the peripheral edge portion forms a sharp edge portion 19 that tapers infinitely between the punch side sliding contact surface 18 that is in sliding contact with the die 14 of the upper and lower punches 11 and 12. As a result, the edge portion 19 is easily damaged and the life of the mold is significantly deteriorated. However, in the vertical blade type throw-away tip, the corner ridge line portion 8 intersects with the corner portion of the rake face 3 to form the corner portion 7 connected to the cutting edges 4 and 6. If the tip of the edge portion 19 is chamfered with a flat surface as in Literature 2, the shape is transferred as a step between the corner portion 7 and the cutting blade 6 as it is. Damage cannot be prevented.

  The present invention has been made under such a background, and the above-mentioned vertical blade type throw-away tip green compact is separated in a direction corresponding to the thickness direction of the die and the chip body. Even if the corner ridge line portion of the chip body is a ¼ convex arc curved surface shape, the shape of the punch portion is not impaired even when the press dies having the upper and lower punches in contact are formed. An object of the present invention is to provide a method for manufacturing a throw-away tip capable of preventing breakage of the peripheral portion of the press surface, and to provide a green compact press-molding die suitable for use in the manufacturing method.

In order to solve the above-described problems and achieve such an object, a method for manufacturing a throw-away tip according to the present invention includes a circumferential surface disposed around a flat plate surface facing a thickness direction of a substantially flat plate body. A rake face is formed on the surface, and a cutting edge is formed on at least one of an intersecting ridge line between the rake face and the flat plate surface, and an intersecting ridge line between the other peripheral surface adjacent to the rake face and the rake face. In addition, a corner portion connected to the cutting edge is formed at a corner portion of the rake face where these intersecting ridge lines intersect with each other, and an intersecting ridge line portion between the flat plate surface connected to the corner portion and the other peripheral surface is formed. A method of manufacturing a throw-away tip, which is a corner ridge line portion, and further has a tip mounting hole formed in the tip body that opens in the flat plate surface and penetrates the tip body in the thickness direction. One corresponding to the direction And a punch that is relatively spaced apart from each other and a die that is disposed so as to surround the adjacent punches and that defines a cavity between the punches. When the green compact is pressed by pressing the raw material powder of the chip body put into the cavity with the punch, the chip body has a convex curved surface or a chamfered flat surface. And forming at least a part of the portion corresponding to the corner ridge line portion on the inner surface of the concave portion formed on the die side of the press mold, and between the punches close to each other in the cavity. Protruding portions that project in a direction corresponding to the thickness direction are provided, and through holes are formed in the green compact.

The green compact press-molding die of the present invention is a green compact press-molding die used in such a throw-away chip manufacturing method, and corresponds to the thickness direction of the chip body. Punches that are opposed to each other and relatively close to each other, and a die that is disposed so as to surround the adjacent punches and that defines a cavity between the punches. A depression is formed on the die side sliding contact surface that is in sliding contact with the punch, and a recess that retreats in accordance with the corner ridge line portion of the chip body in the green compact is formed. The projection is formed so as to be continuous with the surface, and a protrusion protruding in a direction corresponding to the thickness direction is provided between the punches close to each other in the cavity.

Therefore, for example, when such a press molding die is used, the concave portion formed in the die is formed so as to recede with respect to the die side sliding contact surface that is in sliding contact with the punch to be separated from the die, and the inner surface of the concave portion. However, in the method of manufacturing the throw-away tip having the above configuration, the raw material powder charged into the cavity defined by the die and the punch is used. , by Takashimitsu in a recess formed in the die by the compression by the punch, at least a part of the portion corresponding to the corner ridge portion of the tip body in a compact, rather than a press molding die punch side of the die It will shape | mold by the inner surface of the recessed part formed in the side. For this reason, even if the corner ridge line portion of the chip body is a convex curved surface curved in a convex shape from the other peripheral surface to the flat plate surface, it corresponds to the corner ridge line portion of the green compact. Whereas the portion is also a convex curved surface, the portion connected to the punch that is close from the concave portion in the cavity for molding the portion corresponding to the corner ridge line portion of the green compact is, for example, substantially circular in cross section Even when the concave curved surface is formed, the inner surface portion of the concave portion that forms at least a part of the portion corresponding to the corner ridge line portion is formed on the punch-side press surface of the concave curved surface. Excluded part.

That is, when the cavity is formed with the punch approaching, the inner surface of the cavity is partly formed by the inner surface of the concave portion corresponding to the corner ridge line portion. Since the peripheral edge of the surface is connected to the inner surface of the concave portion on the die side where the concave surface is not greatly curved, the angle of the edge formed by the peripheral edge of the press surface and the punch side sliding contact surface that is in sliding contact with the die side sliding contact surface of the punch is determined. It is possible to ensure a large amount, thereby preventing the edge portion from being damaged. In addition, a chip mounting hole is formed in the chip body so as to open in the flat plate surface and penetrate the chip body in the thickness direction, and accordingly, a through hole is also formed in the green compact. Thus, by providing a protrusion that protrudes in a direction corresponding to the thickness direction between the punches that are close to each other in the cavity, the compression direction of the raw material powder by the punch and the direction in which the protrusion protrudes are determined. Therefore, it is possible to suppress a change in the compression ratio of the raw material powder around the protrusion, and to prevent deformation around the mounting hole in the tip body of the manufactured throw-away tip. . In addition, it is desirable that the inner surface of the concave portion connected in this way and the press surface of the punch that is close to be continuous smoothly. For example, a part of the portion corresponding to the corner ridge line portion is formed by the inner surface of the concave portion. In this case, at least at this portion, the inner surface of the concave portion and the press surface of the approaching punch are smoothly continued, so that the corner ridge line portion of the manufactured throwaway tip and the corner portion of the cutting edge Also, it can be formed smoothly without any step or the like. Furthermore, in order to prevent the edge portion from being damaged more reliably, the intersection angle between the punch side sliding contact surface and the press surface, which is in sliding contact with the die side sliding contact surface of the punch, that is, the angle of the edge portion is 45 °. The above is desirable.

On the other hand, the die, if disjunction possible to between the cavity is divided in a direction perpendicular to the direction or the direction corresponding to the thickness direction of the chip body, thus above the recess of the die-side The green compact in which the portion corresponding to the corner ridge line portion is formed can be easily extracted from the press molding die.

  1 and 2 are cross-sectional views showing a first embodiment of a press-molding die of the present invention used in the method for manufacturing a throw-away tip of the present invention. An embodiment of a method for producing a throw-away tip of the present invention using such a press molding die will also be described. The press-molding die of this embodiment is for molding a green compact of a throw-away tip having a rectangular flat plate-like tip body 1 as shown in FIG. The upper and lower punches 21 and 22 that are opposed to each other by a driving means (not shown) facing each other in the direction corresponding to the direction (vertical direction in FIG. 1; hereinafter simply referred to as the chip thickness direction) are approached. A die 24 is provided so as to surround the punches 21 and 22 and define a cavity 23 between the punches 21 and 22.

  The die 24 is composed of an upper die 24A and a lower die 24B which are divided into two from the substantially center in the chip thickness direction with the cavity 23 in between, and these upper and lower dies 24A and 24B are also formed. The die 24 can be relatively separated from and attached to the chip thickness direction by a driving means (not shown), and the die 24 is formed by the close contact between the two and the lower die 24B. The lower punch 22 inserted from the lower side is raised, and the upper punch 21 is inserted and lowered from the upper side into the upper die 24A to define the cavity 23 as shown in FIG. . The upper and lower punches 21 and 22 and the upper and lower dies 24A and 24B of the die 24 are slidably brought into contact with the punch side sliding contact surfaces 21A and 22A and the die side sliding contact surface 24C. It is configured to be inserted into the dies 24A and 24B (however, for the sake of explanation, a large gap is formed between the punch side sliding contact surfaces 21A and 22A and the die side sliding contact surface 24C. Actually, this gap is about a few microns.)

  Further, in the cavity 23 thus defined, a pin 25 protruding in the chip thickness direction is provided as a protrusion in the present embodiment between the upper and lower punches 21 and 22 that are close to each other. That is, the pin 25 has a cylindrical shape, and is inserted into a circular hole 22C formed in the lower punch 22 so as to open in the center of the press surface 22B on the upper surface of the lower punch 22, and is also not shown. Thus, it can be projected and retracted into the cavity 23 from the press surface 22B in the chip thickness direction independently of the lower punch 22. On the other hand, the upper punch 21 is formed with a circular hole 21C that is also opened at the center of the press surface 21B on the lower surface thereof, and the tip (upper end) portion of the pin 25 protruding into the cavity 23 is formed on the upper punch 21. The punch 21 is received by being inserted into the circular hole 21 </ b> C.

  In order to mold the green compact manufactured on the above-mentioned vertical blade type throw-away tip with such a press molding die, before the upper punch 21 is inserted into the upper die 24A in the cavity 23, Raw material powder of a throwaway tip such as cemented carbide mainly composed of WC or cermet mainly composed of TiC-TiN is introduced from the opening, and this raw material powder is used as the press surface 21B of the upper punch 21 and the lower punch. It compresses in the cavity 23 with the press surface 22B of 22. Accordingly, a green compact having a shape corresponding to the shape of the inner surface of the cavity 23 including the projecting pin 25 is formed.

  Here, the cross-sectional views shown in FIGS. 1 and 2 show the cavity 23 along the cross section corresponding to the cross section parallel to the rake face 3 of the throw-away tip shown in FIG. The upper and lower punches 21 and 22 approach the chip thickness direction and compress the raw material powder as described above, thereby compressing the press surfaces 21B and 22B in the chip thickness direction. A flat plate surface of the green compact corresponding to the flat plate surface 2 of the chip body 1 is formed by a flat portion perpendicular to the chip. Further, a pair of peripheral surfaces of the green compact corresponding to the rake face 3 of the throw-away tip of the negative type is disposed on the front side and the back side of the drawings of FIGS. The inner surface of the die 24 (not shown) is formed by a flat surface parallel to the chip thickness direction.

  The other peripheral surface of the green compact corresponding to the other peripheral surface 5 in the rectangular flat chip body 1 is perpendicular to the flat surface (not shown), and the inner periphery of the die 24 extending in the chip thickness direction. In this embodiment, as shown in FIG. 1, a concave portion 26 that retreats with respect to the die side sliding contact surface 24C is paired with the green compact in this embodiment. The presses of the upper and lower punches 21 and 22 that are formed on both sides of the cavity 23 in accordance with the other peripheral surfaces to be formed, and the inner surfaces 27 of the recesses 26 approach each other to define the cavity 23. The surfaces 21B and 22B are connected to each other through the die side sliding contact surface 24C. Here, in the present embodiment, the inner surface 27 of the recess 26 is connected to the press surfaces 21B and 22B defining the cavity 23 via the die-side sliding contact surface 24C. A bottom surface 27A extending in the chip thickness direction parallel to the contact surface 24C and retracted by one step from the die-side sliding contact surface 24C, and both edges of the bottom surface 27A in the chip thickness direction (upper and lower ends of the recess 26) The bottom wall 27B stands up to the bottom surface 27A and continues to the die side sliding contact surface 24C. The bottom surface 27A and the wall surface 27B are formed so as to be in smooth contact with each other.

  However, by forming such a concave portion 26, the raw material powder charged into the cavity 23 is caused to have the chip thickness within the cavity 23 by the press surfaces 21B and 22B of the upper and lower punches 21 and 22, as described above. In addition to being compressed in the vertical direction, the concave portion 26 is also filled with pressure to receive pressure, and is formed into a green compact having a shape corresponding to the shape of the inner surface of the cavity 23 including the concave portion 26. Therefore, the other peripheral surface of the green compact corresponding to the other peripheral surface 5 of the chip body 1 is formed by the bottom surface 27A of the inner surface 27 of the concave portion 26, and the other peripheral surface The portion corresponding to the corner ridgeline portion 8 of the chip body 1 located at the intersection ridgeline portion with the flat plate surface of the green compact (hereinafter referred to as the green compact corner ridgeline portion) is at least the other circumference. A part of the surface side is formed by the wall surface 27 </ b> B of the inner surface 27 of the recess 26.

  However, in the present embodiment, only a part of the green compact corner ridge line portion is formed by the concave portion 26, and the remaining portion is formed in the concave portion 26 in a state where the cavity 23 is defined. Molding is performed by the peripheral surfaces of the press surfaces 21B and 22B on the upper and lower punches 21 and 22 side, which are connected via the die side sliding contact surface 24C and the punch side sliding contact surfaces 21A and 22A. That is, in this embodiment, the corner ridge line portion 8 in the tip body 1 of the throw-away tip to be manufactured is a convex curved surface as described above, more specifically, a convex curved surface that is curved in a convex circular arc shape, that is, ¼ convex. Corresponding to the cylindrical surface, the green compact corner ridge is also a convex curved surface (1/4 convex cylindrical surface). Therefore, the concave portion 26 of the cavity 23 for molding the green compact corner ridge. The corners connected to the upper and lower punches 21 and 22 are formed in a concave curved surface shape (1/4 concave cylindrical surface). In the press molding die of this embodiment, as shown in an enlarged view in FIG. Half of the 1/8 concave cylindrical surface portion is formed by the wall surface 27B, and the remaining 1/8 concave cylindrical surface portion is the edge on the punch side sliding contact surface 21A, 22A side of the press surfaces 21B, 22B connected to the wall surface 27B. Because it is formed That.

  For this reason, also in the present embodiment, the above-described edge portions of the press surfaces 21B and 22B of the punches 21 and 22 are provided with the concave curved surface (1/8 concave cylindrical surface) portion and the punch side sliding contact surfaces 21A and 22A. The edge portion 28 that is tapered is formed by intersecting with the edge portion 28. In the case shown in FIG. 16, the edge portion 19 is tapered as much as possible. The crossing angle α between the sliding contact surfaces 21A and 22A and the concave surfaces of the press surfaces 21B and 22B is 45 ° in the present embodiment because the concave surface is a 1/8 cylindrical surface. On the other hand, the angle β formed by the concave curved surface (1/8 concave cylindrical surface) formed by the wall portion 27B on the inner surface 27 of the concave portion 26 with respect to the center C is also 45 °.

  The concave curved surfaces of the edges of the press surfaces 21B and 22B at the edge portions 28 of the punches 21 and 22 are smoothly in contact with the plane portion perpendicular to the chip thickness direction at the center of the press surfaces 21B and 22B. ing. Further, in the state where the upper and lower punches 21 and 22 are brought close to each other to define the cavity 23, the concave curved surface formed by the edges of the press surfaces 21B and 22B and the wall portion 27B on the inner surface 27 of the concave portion 26 on the die 24 side are formed. The concave curved surface is also made to continue smoothly through the punch side sliding contact surfaces 21A and 22A and the die side sliding contact surface 24C which are in sliding contact with each other.

  Therefore, in the manufacturing method of the throw-away tip of the present embodiment using the press-molding die configured as described above, first, the punches 21 and 22 are separated from and contacted with each other in the tip thickness direction, whereby a green compact is obtained. Therefore, the raw material powder can be compressed relatively uniformly, and a throw-away tip with little dimensional error due to deformation or the like can be manufactured. In particular, even when the mounting hole 9 that penetrates the chip body 1 in the thickness direction is formed, the punches 21 and 22 separate the pin 25 that molds the through hole that becomes the mounting hole 9 into the green compact. Since it can project into the cavity 23 in the direction of contact, it is possible to reliably prevent deformation of the periphery of the mounting hole 9 of the chip body 1 due to change in the compression ratio of the raw material powder around the pin 25. It becomes possible.

  In this embodiment, when the green compact is formed by compressing the raw material powder thus introduced into the cavity 23 by the punches 21 and 22, in this embodiment, the raw material powder is packed in the recess 26 formed on the die 24 side. Thus, as described above, a part of the ridge line portion of the green compact is formed by the inner surface 27 (wall portion 27B) of the concave portion 26, that is, formed on the die 24 side instead of the punches 21 and 22 side. It becomes. For this reason, even if the green compact corner ridge is a convex curved surface and the inner surface of the cavity 23 for forming the green compact corner ridge has to be a concave curved surface, It is possible to prevent the edge portions 28 at the edges of the press surfaces 21B and 22B of the punches 21 and 22 forming the remaining portion of the corner ridge line portion from being excessively tapered, and these punches 21 and 22 are fitted to the die 24. It is possible to prevent breakage such as chipping at the tip of the edge portion 28 when being inserted and separated, and it is possible to extend the life of the press mold.

  Further, in the press molding die of this embodiment, the wall portion 27B of the inner surface 27 of the concave portion 26 for molding a part of the green compact corner ridge line portion, and the concave curved surface of the edge portion 28 for molding the remaining portion, However, since the punches 21 and 22 are close to each other so as to smoothly contact with the cavity 23 being defined, for example, as in the case of chamfering the edge tip described in Patent Document 2, the green compact is used. There are no steps or protrusions due to chamfering in the corner ridge line part or the corner ridge line part 8 of the chip body 1 and the corner part 7 connected to the cutting edge 6, and in order to eliminate such steps and protrusions, the throw-away tip is manufactured. There is no need for post-processing later. Therefore, according to the present embodiment, even a sintered skin throw-away tip called a so-called M class can be used as it is for processing to obtain sufficient accuracy.

  By the way, in this embodiment, the green compact corner ridge line portion is a 1/4 convex cylindrical surface, and a 1/8 concave cylindrical surface portion forming half of this in the press molding die is a concave portion 26 on the die 24 side. Further, a 1/8 concave cylindrical surface portion for forming the other half is formed on the edge portion 28 at the edge of the press surfaces 21B and 22B of the punches 21 and 22, whereby the concave curved surface (1 / 8 concave cylindrical surface) and the crossing angle α between the punch-side sliding contact surfaces 21A and 22A, and the concave curved surface (1/8 concave cylindrical surface) of the inner surface 27 of the concave portion 26 of the die 24 is the center C. Are both set to 45 °.

  However, when the angle β is reduced, that is, when the portion of the corner ridge line portion formed on the concave portion 26 side of the die 24 is small, the portion formed by the concave curved surface of the edge portion 28 of the punches 21 and 22 conversely. Is increased, and the edge portion 28 is extended to a point where the concave curved surface is greatly curved from the flat portions of the press surfaces 21B and 22B, the crossing angle α is also decreased, and the strength of the tip of the edge portion 28 is impaired. As a result, the above-described effects may not be sufficiently achieved. Therefore, it is desirable that the crossing angle α and the angle β when the corner ridge line portion has a circular arc shape such as a 1/4 convex cylindrical surface be 45 ° or more, and 60 ° or more. It is more desirable.

  On the other hand, it is sufficient that at least a part of this green compact corner ridge line portion is formed by the concave portion 26 on the die 24 side. That is, as shown in FIG. / 4 concave cylindrical surface may be formed, and the whole of the green compact corner ridge line portion may be formed by the concave portion 26. Further, as shown in FIG. 4, the wall surface 27B has the 1/4 concave portion of FIG. A part of the flat plate surface of the green compact corresponding to the flat plate surface 2 of the chip body 1 may be formed by the recess 26 by being extended by a wall surface smoothly connected to the cylindrical surface. In FIGS. 3 and 4 and subsequent drawings, the same reference numerals are assigned to the same elements as those in the first embodiment shown in FIGS. 1 and 2, and description thereof is omitted. The illustration of 25 is also omitted.

  Therefore, in the cases shown in FIGS. 3 and 4, the edge portions 28 that are tapered are not formed at the edges of the press surfaces 21B and 22B of the punches 21 and 22, but the punch side sliding contact surfaces 21A and 22A and the press surfaces are formed. The crossing angle α between 21B and 22B and the angle β formed by the concave curved surface (¼ concave cylindrical surface) -shaped wall portion 27B of the inner surface 27 of the concave portion 26 on the die 24 side with respect to the center C are both 90 °. It becomes. However, when the green compact portion formed by the concave portion 26 becomes larger in this way, the retreat amount by which the concave portion 26 retracts from the die side sliding contact surface 24C, that is, the depth D of the concave portion 26 also increases, and the raw material powder by the punches 21 and 22 increases. There is a possibility that the raw material powder filled in the concave portion 26 is not sufficiently compressed during the compression. For this reason, it is desirable that the depth D of the concave portion 26 be equal to or less than the distance L between the plane portions of the press surfaces 21B and 22B when the punches 21 and 22 approach and the cavity 23 is defined. It is more desirable to be L / 2 or less. In other words, the width of the portion formed by the concave portion 26 in the green compact is desirably less than or equal to the thickness of the green compact, and more desirably less than half the thickness of the green compact.

  In the press mold of this embodiment, the die 24 can be separated into and separated from the upper die 24A and the lower die 24B in the chip thickness direction in which the punches 21 and 22 are separated from each other with the cavity 23 therebetween. In other words, these upper and lower dies 24A and 24B are divided at the position of the bottom surface 27A of the inner surface 27 of the concave portion 26 on the die 24 side constituting the cavity 23. Therefore, the concave portion 26 is filled with the raw material powder. Even if the green compact is molded, it can be easily extracted by separating the die 24 by separating the upper and lower dies 24A and 24B. However, in the present embodiment, the die 24 is thus separated in the chip thickness direction so as to be able to be separated and contacted. However, for example, as shown in the plan view shown in FIG. The powder is divided in a direction parallel to the peripheral surface, or a direction parallel to the other peripheral surface of the green compact corresponding to the other peripheral surface 5 of the chip body 1 as shown in the plan view of FIG. For example, the die 24 may be divided in a direction perpendicular to the chip thickness direction so as to be separable. Further, in the present embodiment, the case where the die 24 is completely divided so as to be separable is described. However, if the portion of the green compact formed by the concave portion can be extracted, the die is partially divided and partially It may be possible to connect and disconnect.

  By the way, in the present embodiment, the rake face 3 of the chip body 1 as shown in FIG. 14, the flat plate portion 2 serving as the flank, the other peripheral surface 5, and the corner ridge line portion 8 include the cutting edges 4, 6 and Although the case of manufacturing a negative type throw-away tip orthogonal to each other via the corner portion 7 has been described, for example, the rake face 3 and the flat plate portion 2, the other peripheral surface 5, and the corner ridge line portion 8 include Also in the case of manufacturing a positive type throw-away tip that intersects an acute angle, the manufacturing method having the above-described configuration and the press mold of the green compact can be applied. However, in this case, the corner ridge line portion 8 of the chip body 1 and the green compact corner ridge line portion are convex cylindrical surfaces that intersect at an acute angle with respect to the rake face 3 and the peripheral surface of the green compact corresponding thereto. Or the cavity 23 is also formed so that the front side of the drawing in FIG. 1 is the rake face 3 side, and the cross-sectional dimension gradually decreases toward the back side of the drawing. Is done.

  Further, in the present embodiment, the corner ridge line portion 8 and the green compact corner ridge line portion of the chip body 1 have a convex cylindrical surface shape, and the cross section thereof has a convex arc shape. The concave surface of the inner surface 27 of the concave portion 26 of the die 24 for forming the corner ridge line portion and the concave curved surface of the edge portion 28 of the punches 21 and 22 are also concave cylindrical surfaces having a concave arc shape in section. In the case where the corner portion 7 is a curve other than the convex arc shape, the concave curved surface of the wall portion 27B or the edge portion 28 may be formed in a concave curved surface shape corresponding to this. Further, in some cases, the corner portion 7 may have a straight line shape that intersects the cutting edges 4 and 6 with an angle. In this case, the corner ridge line portion 8 and the green compact corner ridge line portion have a chamfered planar shape. Accordingly, the wall portion 27B may be formed in a planar shape that intersects with the bottom surface 27A of the concave portion 26 at an angle. Further, when the cross-sectional shape such as a convex arc shape with a desired accuracy cannot be obtained in these portions after sintering due to minute deformation of the corner portion 7 and the corner ridgeline portion 8 of the chip body 1, for example, in these portions Microdeformation in the direction of correcting this microdeformation, for example, by forming the concave surface of the wall 27B or the edge portion 28 into a concave curved surface shape such that the corresponding section of the green compact has a convex micro elliptical arc shape. The green compact thus formed may be molded.

  Furthermore, in the first embodiment, the flat plate surface 2 of the chip body 1 is a flat surface perpendicular to the thickness direction of the chip body 1, and thus a flat portion corresponding to the flat portion 2 of the green compact is formed. The press surfaces 21B and 22B of the upper and lower punches 21 and 22 are also flat surfaces perpendicular to the chip thickness direction except for the edge portion where the edge portion 28 is formed. For example, FIG. 7 and FIG. As shown in the second embodiment, the press surfaces 21B and 22B have a convex shape such as a V-shaped cross section. The flat plate surface 2 of the chip body 1 is not flat, and the V-shape or the like is bent in the direction in which the cutting edge 4 extends. It may be made to have a valley shape. Here, FIG. 8 is an enlarged view of a portion that continues from the concave portion 26 to the press surface 21B of the punch 21 in this case. When the flat plate surface 2 of the chip body 1 is thus formed in a V-shaped valley shape, 7 has an arc shape larger than a 1/4 arc, and accordingly, the corner ridge line portion 8 and the green compact corner ridge line portion of the chip body 1 are also formed in a convex cylindrical surface shape larger than the 1/4 cylindrical surface, so that the die 24 side The concave curved surface extending from the wall surface 27B of the concave portion 26 to the edge of the press surface 21B on the punch 21 side has a concave cylindrical surface shape larger than the quarter cylindrical surface.

  In FIG. 8, the position of the die side sliding contact surface 24C is the same as that shown in FIG. 3, that is, the wall surface 27B forms a 1/4 concave cylindrical surface and the angle β is 90 °. The remaining concave cylindrical surface is formed on the edge of the press surface 21B having a convex V-shaped cross section of the punch 21, and the intersection angle α between the concave cylindrical surface and the punch side sliding contact surface 21A is also 90. For example, as shown by a broken line in FIG. 8, the positions of the die side sliding contact surface 24C and the punch side sliding contact surface 21A are shifted to the protruding end side of the convex V-shaped press surface 21B. If the angle β is larger than 90 °, the crossing angle α between the punch-side sliding contact surface 21A of the punch 21 and the press surface 21B is also an obtuse angle larger than 90 °. Can be more reliably prevented. In addition, as in the second embodiment, when at least one of the press surfaces 21B and 22B of the punches 21 and 22 has a convex shape such as a V-shaped cross section, the raw material powder is compressed when compressed by the punches 21 and 22. Since the recess 26 is more reliably filled and pressed, there is also an advantage that the moldability of the green compact can be further stabilized.

  Furthermore, in the first and second embodiments, a throw-away tip is manufactured in which the other peripheral surface 5 of the tip body 1 serving as a flank of the cutting blade 6 extends in parallel to the thickness direction of the tip body 1. However, as in the third embodiment shown in FIG. 9, for example, the inner surface of the concave portion 26 on the die 24 side that forms another peripheral surface corresponding to the other peripheral surface 5 in the green compact. 27 is formed so as to be inclined with respect to the chip thickness direction, and the throw away tip and the green compact also have the other peripheral surface 5 of the chip body 1 and the green compact corresponding thereto. Other peripheral surfaces may be formed to be inclined surfaces inclined with respect to the respective thickness directions. In the third embodiment, the interval between the bottom surfaces 27A of the recesses 26 arranged on both sides of the cavity 23 is gradually increased from the lower punch 22 side toward the upper punch 21 side in the chip thickness direction. In such a case, in order to divide the die 24 into upper and lower dies 24A and 24B in the chip thickness direction so that they can be separated from each other, the divided surface is as shown in FIG. Furthermore, the inner surface 27 of the recess 26 may be positioned at the most receding portion from the die-side sliding contact surface 24C of the upper die 24A from the bottom surface 27A inclined to the concave wall surface 27B.

  FIG. 10 is a cross-sectional view showing a fourth embodiment of the press molding die of the present invention. In this embodiment, the upper and lower punches 21 and 22 are further provided with the flat plate of the chip body 1 in the green compact. Upper and lower inner punches 21D and 22D for forming a flat surface perpendicular to the chip thickness direction in a portion corresponding to the center of the surface 2, and portions corresponding to both outer sides of the flat surface of the flat plate surface 2 Except for the green compact according to the second embodiment, the upper and lower outer punches 21E and 22E are formed into valleys having a V-shaped cross section. These upper and lower inner and outer punches 21D, 22D, 21E and 22E are mutually connected. Independently, it can be relatively separated in the chip thickness direction. Accordingly, the press surfaces 21B and 22B of the upper and lower inner punches 21D and 22D are perpendicular to the chip thickness direction, and the press surfaces 21B and 22B of the upper and lower outer punches 21E and 22E are the concave portions of the die corner 24, that is, the die 24 The inclined surfaces gradually increase in distance from each other toward the 26 side.

  Therefore, in the press molding die of the fourth embodiment as described above, at least a part of the green compact corner ridge line portion is formed on the die 24 side, and particularly, with the press surfaces 21B and 22B of the outer punches 21E and 22E. It is possible to ensure the strength of the intersecting ridge line portion with the punch side sliding contact surfaces 21A and 22A. The configuration described in the second embodiment can also be applied to the fourth embodiment. Further, in the present embodiment, the punches 21 and 22 are divided into inner and outer punches 21D, 22D, 21E, and 22E so that they can be independently separated from each other. Therefore, when the raw material powder charged into the cavity 23 is compressed. First, the inner punches 21D and 22D are brought close to each other and the raw material powder is pushed outward, and then the outer punches 21E and 22E are brought closer to push the raw material powder pushed to the outside further outward. Thus, it is possible to make the raw material powder dense in the recess 26.

  By the way, in the first to fourth embodiments, the case of manufacturing the rectangular flat plate type vertical blade type throwaway tip as shown in FIG. 14 has been described. The present invention (particularly, the configuration of the fourth embodiment) can also be applied to manufacture a throw-away tip having a substantially triangular flat plate-like tip body 1 as shown in FIG. This throw-away tip is used for grooving of a work material and the like, and one of the flat plate surfaces 2 (in FIG. 12) of the triangular plate surface 2 facing the thickness direction of the chip body 1. The upper flat plate surface 2) is a flat surface perpendicular to the thickness direction, and the other flat plate surface 2 (the lower flat plate surface 2 in FIG. 12) is substantially flat. In the corner portion of the triangle formed by the flat plate surface 2, one of a pair of peripheral surfaces adjacent to each other at the corner portion is a rake face 3 and the other peripheral surface 5 is a flank face. The ridge line intersecting with the peripheral surface 5 is the cutting edge 6.

  And the corner part 7 which makes convex arc shape is formed in the both ends of this cutting blade 6, The intersection ridgeline part of the said other surrounding surface 5 and the said corner | angular part of the flat plate surface 2 which continue to these corner parts 7 Is the corner ridgeline 8. Further, of the corner portions of the flat plate surface 2 intersecting with the corner ridge line portions 8, the portion on the one flat plate surface 2 side extends from the corner ridge line portion 8 to the flat surface side of the central portion of the flat plate surface 2. It is set as the inclined surface which inclines toward the said other flat plate surface 2 of an other side as it goes. Therefore, when such a triangular flat plate-shaped throw-away tip is manufactured from a green compact by powder press molding, the green compact also becomes a triangular flat plate shape. In the method and mold for forming a green compact by compressing in a direction perpendicular to the thickness direction, it becomes increasingly difficult to uniformly compress the raw material powder, and it cannot be practically manufactured.

  FIG. 13 is a sectional view showing a fifth embodiment of the press-molding die of the present invention in the case of manufacturing such a throwaway tip (corresponding to the ZZ section of the throwaway tip shown in FIG. 11). In this embodiment, as in the fourth embodiment, the upper and lower punches 21 and 22 are composed of upper and lower inner punches 21D and 22D and upper and lower outer punches 21E and 22E, respectively. 21D, 22D, 21E, and 22E can be relatively separated from each other in the chip thickness direction independently of each other. However, on the upper punch 21 side, the press surface 21B of the upper inner punch 21D is formed in the chip thickness direction so as to form a portion corresponding to the flat surface of the central portion of the one flat plate surface 2 in the green compact. On the other hand, the upper and outer punches 21E have three upper and outer punches arranged around the upper and inner punches 21D in accordance with the corner portions of the green compact formed into a triangular flat plate shape. The press surface 21B is gradually separated from the press surface 22B of the lower punch 22 toward the compaction corner ridge line side, that is, the concave portion 26 side of the die 24. It is supposed to be an inclined surface that increases.

  On the other hand, on the lower punch 22 side, the lower inner punch 22D and the three lower outer punches 22E are disposed at positions facing the upper inner punch 21D and the three upper and outer punches 21E of the upper punch 21, respectively. Of these, the three lower and outer punches 22E can be separated from each other in the chip thickness direction toward the upper and outer punches 21E in the same manner as the upper and outer punches 21E. However, the press surfaces 22B of the lower inner and outer punches 22D and 22E are both flat surfaces perpendicular to the chip thickness direction in accordance with the substantially entire other flat surface 2 of the chip body 1 being flat. The cavities 23 are flush with each other in a defined state. Therefore, in the present embodiment, only the press surface 21B of the upper and outer punches 21E is an inclined surface inclined with respect to a plane perpendicular to the chip thickness direction. The die 24 is divided into three parts at positions corresponding to the respective corner portions of the triangular flat plate-shaped green compact, and can be separated from and attached in a direction perpendicular to the chip thickness direction.

  Therefore, according to the press-molding die of the fifth embodiment as described above, even the throw-away tip having the triangular flat plate-like tip body 1 as described above can be easily obtained from the green compact obtained by uniformly compressing the raw material powder. Even if the corner ridgeline portion 8 of the chip body 1 has a convex curved shape, the press surfaces 21B, 22B of the upper and lower outer punches 21E, 22E and the punch side sliding contact surface 21A, The strength of the intersection ridge line with 22A can be secured. Of these, the press surface 21B of the upper and outer punches 21E is an inclined surface that gradually separates from the press surface 22B of the lower outer punch 22E that is a flat surface perpendicular to the opposing chip thickness direction toward the recess 26 side. Therefore, it is possible to more reliably and efficiently pack the raw material powder in the recess 26.

  In addition, in the first embodiment shown in FIG. 1, or in the first embodiment shown in FIG. 1, or in the modified example and the second to second embodiments, the through hole that becomes the mounting hole 9 of the chip body 1 is formed in the green compact. Also in the fifth embodiment, a cylindrical pin 25 is provided as a protrusion from the press surface 22B of the lower punch 22 so as to be able to protrude and retract in the cavity 23 in the chip thickness direction, and the pin 25 is protruded. After the raw material powder is put into the cavity 23, the pin 25 is accommodated in the circular hole 21C of the upper punch 21, and the upper and lower punches 21 and 22 are relatively brought close to each other to form a green compact. Thus, the through hole is formed in the green compact. In this case, the through hole and the mounting hole 9 must be cylindrical holes having a constant inner diameter over the entire length. However, such a throw-away tip mounting hole 9 may be formed such that the opening at one end or both ends thereof is widened so that the inner diameter increases toward the opening, such as a dish shape or a bell shape. .

  Therefore, in order to form a through-hole serving as the mounting hole 9 having such a shape into a green compact so that the opening on the surface side formed by the press surface 21B of the upper punch 21 is enlarged, Instead of forming the circular hole 21C in the punch 21, it protrudes toward the lower punch 22 side in the chip thickness direction on the press surface 21B of the upper punch 21, and its outer diameter faces the press surface 21B side. After the core portion that expands so as to increase in diameter is formed as the protruding portion and the upper and lower punches 21 and 22 are relatively approached and the tip of the core portion comes into contact with the tip of the pin 25, this contact state The green compact may be formed while the pin 25 is retracted and pushed into the circular hole 22 </ b> C of the lower punch 22. Further, in order to mold the green compact so that the surface side through-hole opening formed by the press surface 22B of the lower punch 22 has a larger diameter, the core whose outer diameter increases toward the press surface 22B side. The portion may be provided as the above-described protrusion so as to be able to protrude and retract from the press surface 22B instead of the pin 25. In addition, when the core portion whose diameter is increased toward the press surfaces 21B and 22B is used as the protrusion protruding in the chip thickness direction in the cavity 23, the green compact is formed by the outer peripheral surface of the core portion. At this time, since the raw material powder is pushed out to the outer peripheral side of the core portion, that is, the concave portion 26, the advantage that the filling of the raw material powder into the concave portion 26 can be made more reliable and efficient is also obtained.

It is sectional drawing which shows 1st Embodiment of the press molding die of this invention. It is an expanded sectional view of A part in FIG. It is an expanded sectional view equivalent to the A section showing a modification of the first embodiment shown in FIG. It is an expanded sectional view equivalent to A section showing other modifications of a 1st embodiment shown in Drawing 1. It is the top view seen in the chip thickness direction which shows the modification of the division | segmentation of the die | dye 24 of 1st Embodiment shown in FIG. It is the top view seen in the chip thickness direction which shows the other modification of the division | segmentation of the die | dye 24 of 1st Embodiment shown in FIG. It is sectional drawing which shows 2nd Embodiment of the press molding die of this invention. It is an expanded sectional view of A part in FIG. It is sectional drawing which shows 3rd Embodiment of the press molding die of this invention. It is sectional drawing which shows 4th Embodiment of the press molding die of this invention. It is a top view which shows a triangular flat plate type vertical blade type throwaway tip. It is a side view of the throw away tip shown in FIG. It is sectional drawing which shows 5th Embodiment of the press molding die of this invention. It is a perspective view showing a rectangular flat plate type vertical blade type throwaway tip. FIG. 15 is a cross-sectional view of a press mold when an attempt is made to manufacture the throw-away tip shown in FIG. 14 in the same manner as the method described in Patent Document 2. It is an expanded sectional view of A part in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tip body 2 Flat surface 3 Rake face 4,6 Cutting edge 5 Other peripheral surface of the chip body 1 7 Corner part 8 Corner ridgeline part 9 Mounting hole 21, 22 Punch 21A, 22A Punch side sliding surface 21B, 22B Press surface 23 cavity 24 die 24C die side sliding contact surface 25 pin 26 recess 27 inner surface 27B of recess 26 inner wall 27B wall surface of recess 26 of inner surface 27 edge C center of concave curved surface formed by wall surface 27B α punch side sliding contact surface 21A and press Intersection angle with the surface 21B β Angle formed by the concave curved wall portion 27B with respect to its center C

Claims (12)

A rake face is formed on the circumferential surface arranged around the flat plate surface facing the thickness direction of the chip body having a substantially flat plate shape, and the ridge line between the rake face and the flat plate surface is adjacent to the rake face. A cutting edge is formed on at least one of the peripheral surface of the rake face and the intersecting ridge line of the rake face, and a corner portion connected to the cutting edge is formed at a corner of the rake face where the intersecting ridge lines intersect with each other. An intersection ridge line portion between the flat plate surface connected to the corner portion and the other peripheral surface is a corner ridge line portion, and the chip main body is opened to the flat plate surface so that the chip main body extends in the thickness direction. A throw-away tip manufacturing method in which a tip mounting hole penetrating through is formed,
Punches that are relatively opposed to each other in a direction corresponding to the thickness direction, and a die that is disposed so as to surround the peripheries of these close punches and defines a cavity between the punches with a press molding die with the door, the raw material powder of the chip body which is put into the cavity upon press forming a green compact by compressing the punch, projecting above the chip body in the green compact At least a part of a portion corresponding to the corner ridge line portion, which is a curved surface or a chamfered planar shape, is molded with the inner surface of the concave portion formed on the die side of the press molding die, and in the cavity Is provided with a protrusion protruding in a direction corresponding to the thickness direction between the punches close to each other to form a through hole in the green compact. Method for producing a flop. In the die, the recess retracts against the die-side sliding contact surface in sliding contact with the punch, the inner surface of the recess is formed so as to be continued to the pressing surface of the punch has approached, the chip in the green compact The method for manufacturing a throw-away tip according to claim 1, wherein at least a part of a portion corresponding to a corner ridge line portion of the main body is formed by an inner surface of the concave portion.   3. The corner ridge line portion of the chip body is formed to be smoothly continuous so that the inner surface of the recess and the press surface of the approaching punch are smoothly continuous. Method of throwaway chips.   Forming a portion corresponding to the corner ridge line portion of the green compact from the concave portion in the cavity, a portion connected to the approaching punch is formed into a concave curved surface, and the corner ridge line portion of the green compact is formed. And a corner ridge line portion of the chip body is formed into a convex curved surface curved in a convex shape from the other peripheral surface to the flat plate surface. The manufacturing method of the throw away tip of Claim 2 or Claim 3.   5. The method of manufacturing a throw-away tip according to claim 4, wherein the concave curved surface has a substantially arc-shaped cross section, and the corner ridge line portion of the chip body is a convex curved surface curved in a convex arc shape in cross section.   The die is divided into a direction corresponding to the thickness direction of the chip body or a direction perpendicular to the direction of the chip body with the cavity in between, and can be separated from and attached to the die. 6. The method of manufacturing a throw-away tip according to claim 1, wherein the throw-away tip is extracted by being divided and separated. A green compact press-molding die used in the throw-away tip manufacturing method according to any one of claims 1 to 6, wherein the die is opposed to each other in a direction corresponding to a thickness direction of the tip body. A punch that is relatively separated from the punch, and a die that is disposed so as to surround the adjacent punches and that defines a cavity between the punches. The die slides on the punch. A concave portion is formed in the green compact so as to recede in accordance with the corner ridge line portion of the chip main body, and the inner surface of the concave portion is connected to the press surface of the approaching punch. The green compact press-molding is characterized in that, in the cavity, a protrusion protruding in a direction corresponding to the thickness direction is provided between the punches close to each other. Type.   8. The green compact press-molding die according to claim 7, wherein an inner surface of the concave portion and a press surface of the approaching punch are smoothly continuous.   The powder dust according to claim 7 or 8, wherein an angle of intersection of the punch side sliding contact surface that is in sliding contact with the die side sliding contact surface of the punch and the press surface is 45 ° or more. Body press mold.   The corner ridge line portion of the chip body has a convex curved shape that curves in a convex shape from the other peripheral surface to the flat plate surface, and accordingly, the portion corresponding to the corner ridge line portion of the green compact is also convex. In contrast to the curved surface, the portion connected to the punch that is close to the concave portion in the cavity for molding the portion corresponding to the corner ridge line portion of the green compact is formed in a concave curved surface shape. A green compact press-molding die according to any one of claims 7 to 9.   11. The green compact press-molding die according to claim 10, wherein the concave curved surface has a substantially arc-shaped cross section.   8. The die according to claim 7, wherein the die is divided in a direction corresponding to a thickness direction of the chip main body or a direction perpendicular to the direction with the cavity interposed therebetween, and can be separated from and attached to the die. Item 12. A press-molding die for a green compact according to any one of Items 11.

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