JP2001121310A - Throwaway tip with wear sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To arrange a sensor line of a conductive film on a throwaway tip and connect the sensor line to an external detector circuit or the like without trouble. SOLUTION: A throwaway tip 1 has a pair of contact regions 13 and 14 on a seating surface 6 that is placed into contact with a tip seat on a holder when the tip 1 is mounted on it. The contact regions 13 and 14 are connected to opposite ends of a sensor line 12 via respective connecting lines 15 and 16. When the throwaway tip 1 is mounted on the holder, the seating surface 6 is not exposed out or is protected from direct contact with cutting fluid and chips. The arrangement of both contact regions 13 and 14 on the seating surface 6 of the throwaway tip 1 allows appreciable connection of the sensor line 12 to an external detector circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a throw-away insert used for cutting.

[0002]

2. Description of the Related Art A throw-away tip mounted on a holder or the like and functioning as a cutting blade is known. A throw-away tip is a disposable tip that is replaced without re-polishing when the cutting edge is worn. In general, the indexable insert has a cutting edge formed at each corner of a substantially flat base material based on a square or a triangle. When the cutting edge of one of the corners is worn, the cutting edge of the other corner is used. It is replaced when the cutting edges at all corners are worn.

It is not easy to find out how much the cutting edge of the indexable insert has worn. In particular, it is very difficult in the working environment to detect the wear amount of the cutting edge without interrupting the cutting during the cutting. Conventional methods for detecting the amount of wear on the cutting edge include (1)
A method in which cutting is interrupted, the indexable insert is removed from the holder or the like, and the cutting edge is observed with a tool microscope or the like. (2) A phenomenon accompanying the wear of the cutting edge, such as a decrease in cutting force or vibration. There is a method of detecting an increase in noise, generation of abnormal noise, and the like by a sensor installed near a processing portion on a machine tool, and estimating a wear amount of a cutting edge based on a detection signal.

[0004] However, the method (1) has a problem in that the cutting must be interrupted and the wear of the cutting edge cannot be quantitatively detected, resulting in poor accuracy. In addition, the method (2) requires a complicated detection device, and has a problem that the detection sensitivity of the wear amount is poor and the reliability is low.

A proposal for solving these problems is disclosed in Japanese Utility Model Application Laid-open No.
No. 120323. In this publication,
It is disclosed that a sensor line is formed of a conductive film on a flank of a throw-away tip along a cutting edge. It is also disclosed that the width of the sensor line corresponds to the allowable wear width. Therefore, according to the throw-away tip disclosed in this publication, the sensor line is worn with the wear of the cutting edge, and it is possible to determine that the life of the cutting edge has reached when the sensor line is interrupted.

Japanese Patent Application Laid-Open No. 9-38846 discloses that
For ordinary cutting tools that are not throw-away inserts, a thin-film circuit is provided on the flank of the cutting tool, and when the electrical resistance changes as the thin-film circuit wears due to wear of the flank, the life of the cutting tool is detected. Has been proposed.

[0007]

A method of forming a sensor line of a conductive film on a flank along a cutting edge and detecting a change in resistance value of the line detects the wear of the cutting edge. Preferred as a method. However, when this method is used for a throw-away insert, there is a problem that even if a sensor line is provided along the cutting edge, it is practically difficult to connect the sensor line to an external detection circuit or the like. Encounter.

More specifically, the throw-away tip is a disposable tip as described above, and its size is less than 1 cm ³ . The chip performs cutting while being exposed to a cutting fluid (water or oil) and chips. Under such an environment, a technique of connecting a sensor line formed on a small throw-away chip to an external detection circuit or the like without hindrance has not been realized.

An object of the present invention is to solve the above-mentioned problem and to provide a throw-away chip with a wear sensor capable of performing practical mounting. The main purpose of the present invention is
When mounted on a holder, etc., the sensor line formed on the throw-away tip can be securely connected to the external circuit, and the throw-away tip with a wear sensor that can achieve the connection without interrupting the cutting process It is to provide.

Another object of the present application is to provide a throw-away chip capable of protecting a connection between a sensor line provided in the throw-away chip and an external circuit.

[0011]

The invention according to claim 1 has a substantially flat base material, a rake face on one surface of the base material, and a seating surface on the other surface of the rake face and back to back. A flank is formed on a side surface intersecting the rake face and the seating face, and the throwaway tip in which a cutting edge is formed by an intersection ridge of the rake face and the flank, A sensor line of a conductive film extending along the cutting edge is provided in an electrically insulated state with respect to the base material, and the seating surface has two pairs of pairs electrically connectable to a predetermined circuit. A contact region is provided in an electrically insulated state with respect to the base material, and two connection lines for connecting the two contact regions and one end and the other end of the sensor line, respectively, are provided on the base material surface. Must be electrically insulated from Wherein a throw-away tipped wear sensor.

According to a second aspect of the present invention, the side of the sensor line remote from the cutting edge extends parallel to the cutting edge at a predetermined distance from the cutting edge which is related to wear of the flank. The wearable throwaway tip with a sensor according to claim 1, characterized in that: The invention according to claim 3 is the indexable insert with a wear sensor according to claim 2, wherein the predetermined distance is made equal to a life due to wear of the flank.

According to a fourth aspect of the present invention, the base material is formed of an insulating material, and substantially the entire surface of the base material is covered with a conductive film, and the sensor lines, the connection lines, and the contact areas are formed. 4. The throw-away chip with a wear sensor according to claim 1, wherein the conductive film on the surface is formed by being electrically separated.

According to a fifth aspect of the present invention, the base material is formed of a conductive material, substantially the entire surface of the base material is covered with a non-conductive film, and a conductive film is further formed thereon. hand,
4. The throwaway with a wear sensor according to claim 1, wherein the sensor line, the connection line, and the contact area are formed by electrically separating a conductive film on a surface. 5. Chip.

According to a sixth aspect of the present invention, the processing for electrically separating the sensor line, the connection line, and the contact area from the conductive film on the surface of the base material is performed by laser processing. It is a throw away tip with a wear sensor of 4 or 5. According to the configuration of the first aspect, the sensor line provided on the throw-away tip can be connected to the probe provided on the tip seat of the holder when the throw-away tip is mounted on the predetermined holder. The probe is connected to an external detection circuit and a discrimination circuit via the inside of the holder.

The tip seat of the holder is an area where the seating surface of the throw-away tip is in contact or close contact. The seating surface of the throw-away tip, which is in contact with the tip seat, is not exposed to the outside, so that the cutting fluid (water or oil) or chips does not directly hit. Therefore, if a contact area that can be electrically connected to an external circuit is provided on the seating surface of the throw-away tip, the contact state between the contact area and the tip of the probe provided on the tip seat can be protected from cutting fluid and chips. Can be.

When a probe or the like electrically connected to the contact area of the throw-away tip is provided on the tip seat,
They can be placed inside the holder. Therefore,
The electrical connection provided on the holder is also not exposed from the holder, and is not affected by chips or cutting fluid. Therefore, it is possible to realize a mounting structure for satisfactorily connecting the sensor line of the throw-away chip to an external circuit. As a result, it is possible to accurately detect the life of the throw-away tip using the sensor line.

In particular, if the sensor line is constructed as in claim 2, the wear of the cutting edge and the interruption of the conduction of the sensor line are associated with each other. Can be determined to be in a predetermined wear state. In the third aspect, when the conduction of the sensor line is interrupted, it can be determined that the cutting edge ridge has reached the end of its life.

The method of providing the sensor line, the contact area and the connection line in an electrically insulated state with respect to the base material is as follows.
When the base material is an insulator, it may be formed as described in claim 4. When the base material is a conductive material, a method may be used in which the surface of the base material is once covered with a non-conductive film, and then a conductive film is formed thereon.

Preferably, the sensor line, the connection line and the contact area are formed by laser processing. This is because, according to the laser processing, the processing accuracy is high and the degree of freedom of circuit change is high. According to the present invention, the electrical connection between the sensor line formed on the throw-away tip and the external circuit can be reliably performed, and the connection can be performed without hindering the cutting process. You can get a throwaway tip with.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. FIG. 1A
FIG. 1B is a perspective view of the throw-away tip 1 according to an embodiment of the present invention as viewed from the upper front side, and FIG. 1B is a perspective view of the throw-away tip 1 viewed from the lower front side. The indexable insert 1 has a substantially flat (substantially rectangular parallelepiped) base material 2. The base material 2 is not originally distinguished between upper and lower, but for convenience of explanation, one will be described as an upper surface and the other as a lower surface.

A rake face 5 is formed on the upper surface of the base material 2,
The lower surface of the base material 2 is a seating surface 6. The flank 8 is formed on each of the four side surfaces of the base material 2.
A cutting edge 9 is formed by the intersection of the rake face 5 and each flank 8. Furthermore, the intersection of the rake face 5 and the two adjacent flank faces 8 forms a corner portion 10 usable for cutting.

In the center of the base material 2, a clamp hole 11 is formed which penetrates from the upper surface to the lower surface. The indexable insert 1 is positioned in a chip pocket of a predetermined holder or the like, and is mounted on the holder or the like by screwing a clamp screw into the clamp hole 11. In the mounted state, for example, the upper corner portion 10 in FIG. 1A is used for cutting. When the clamp screw is loosened and the throw-away tip 1 is rotated by 90 ° about the clamp hole 11, another corner portion 10 can be used for cutting. By rotating the throw away tip 1 by 90 ° in this manner,
The four corner portions 10 on the upper surface side can be sequentially used for cutting.

Further, by mounting the throw-away tip 1 upside down on a holder or the like, as shown in FIGS.
In B, the four corner portions on the lower surface side can be sequentially used for cutting. If the bottom corner is used,
The upper surface serves as a seating surface, and the lower surface functions as a rake surface.
As described above, in the indexable insert 1, the eight corner portions 10 of the rectangular parallelepiped base material 2 can be used for cutting, respectively.

For this purpose, each of the eight corner portions 10 is provided with a sensor line 12 of a conductive film extending along the cutting edge 9. The sensor line 12 has a flank 8
It is provided in. Specifically, it extends along the cutting edge 9 on two adjacent flank surfaces 8 forming the corner portion 10 so as to surround the corner portion 10. Sensor line 1
Reference numeral 2 denotes a line of a conductive film having a width W extending along the cutting edge 9 with its upper side being in contact with the cutting edge 9. The sensor line 12 is provided in an electrically insulated state with respect to the base material 2.

The width W of the sensor line 12 is
(The wear limit of the flank 8). Normally, the reference life of the corner portion 10 of this type of throw-away tip 1 is in the range of 0.05 to 0.7 mm, so that the width W of the sensor line 12 is also set to a value equal to the life reference. ing. For example, if the wear of the flank 8 of the throw-away tip 1 is 0.2 mm and the life is reached, the width W of the sensor line 12 is also set to 0.2 mm. When cutting is performed by the corner portion 10, wear of the cutting edge 9 and the flank 8 progresses as the processing time increases. As the wear of the flank 8 progresses, the sensor line 12 also wears accordingly. When the wear width of the flank 8 reaches or exceeds the life reference amount, the sensor line 12 having the width W that matches the life reference amount is disconnected due to wear. Since the resistance value at both ends of the sensor line 12 is measured by an external circuit as described later, when the resistance value of the sensor line 12 becomes infinite, the cutting edge 9 of the corner 10 reaches the end of its life. It can be determined that it has been done.

As shown in FIG. 1B, the seating surface 6 is provided with two paired contact areas 13 and 14. The two contact regions 13 and 14 are formed of a conductive film, and are provided in an insulated state with respect to the base material 2. The contact regions 13 and 14 are regions that can be electrically connected to a resistance detection circuit provided outside the holder, for example. As will be described later, when the throw-away tip 1 is mounted on the holder, a probe of a detection circuit provided on the tip seat of the holder is electrically connected to the contact areas 13 and 14. It is preferable that the contact regions 13 and 14 are as large as possible so that a probe or the like of the detection circuit can be easily contacted.

From the flank 8 of the base material 2 to the seating surface 6, connection lines 15 and 16 are provided in a state of being insulated from the base material 2 by a conductive film. The connection line 15 electrically connects one end 121 of the sensor line 12 to one contact region 13, and the connection line 16 electrically connects the other end 122 of the sensor line 12 to the other contact region 14. Is to be connected to. The connection lines 15 and 16 are lines that are sufficiently thicker than the width W of the sensor line 12, and the electric resistance of the connection lines 15 and 16 is sufficiently larger than the electric resistance of the sensor line 12. Therefore, the connection lines 15 and 16 do not affect the detection of the change in the electric resistance value of the sensor line.

The connection line 16 connected to the other end 122 of the sensor line 12 has a return line 17 at a part thereof. The return line 17 is connected to the other end 122 of the sensor line 12 at a return portion 18. The return line 17 extends parallel to the sensor line 12 at a predetermined distance D from the sensor line 12. By forming a part of the connection line 16 as the return line 17, the connection line 15 and the connection line 16 can be provided on the flank 8 in parallel at a predetermined interval.
6 has the advantage that it can be arranged with good area efficiency.

The distance D between the sensor line 12 and the return line 17 has a width of 0.05 mm or more. Preferably, the width D is wider within an allowable range. That is, when cutting is performed in the corner portion 10, the workpiece is cut by the cutting edge 9 included therein. The shaved chips are generated from the rake face 5 in the direction of the flank 8, for example, while curling. The generated swarf may adhere between the sensor line 12 and the turn-back line 17 and cause an electrical short circuit between the two lines.

Therefore, by making the distance D between the sensor line 12 and the return line 17 wide, it is possible to prevent an electrical short circuit between the two lines 15 and 16 due to the attachment of chips or the like. The two connection lines 15 and 16 formed on the flank 8 are not perpendicular to the sensor line 12 (in other words, relative to the cutting edge 9) but intersect at a predetermined inclination angle. It is an extended, inclined line. The reason is that the arrangement positions of the contact regions 13 and 14 provided on the seating surface 6 which is the lower surface and the arrangement positions of the contact regions 13 and 14 provided on the upper surface are exactly the same.

More specifically, the four corner portions 10 located on the upper surface side in FIG. 1A can be sequentially used for cutting by rotating the indexable insert 1 by 90 °. 90 ° throw-away tip 1
1B, four pairs of contact areas 13, shown in FIG.
14 also rotates by 90 ° in order. Then, the contact areas 13 and 14 connected to the sensor line 12 of the corner portion 10 used for cutting are connected to a probe of an external circuit.
For this reason, four pairs of contact areas 13 provided on the seating surface 6,
Reference numeral 14 denotes a positional relationship of a rotation target of 90 ° with respect to the center of the seating surface 6.

Further, since the throw-away tip 1 can be used upside down, the four pairs of contact regions 13 and 14 provided on the upper surface shown in FIG. 1A are also rotated by 90 ° with respect to the center of the upper surface. The target has a positional relationship. In order to make the contact regions 13 and 14 provided on the upper surface and the contact regions 13 and 14 provided on the lower surface exactly the same as described above, the connection lines 15 and 16 need to be provided obliquely on the flank 8. is there.

Incidentally, in the case of a so-called positive type in which only a single-sided (for example, upper surface) corner portion is used for cutting, etc., the connection lines 15 and 16 may not be obliquely provided on the flank 8. is there. FIG.
Are provided on the seating surface 6 of the throw-away tip 1.
It is a top view which shows the modification of a contact area 13 and 14 of a pair.
The seating surface 6 is provided with four pairs of contact areas 13 and 14, each of which comes into contact with a probe of an external circuit when the corresponding corner is used for cutting.

When the contact areas 13 and 14 are connected to an external circuit and the electric resistance of the sensor line 12 is measured, a predetermined voltage is applied to one of the contact areas 13 from the external circuit, and the other is applied. Are connected to the ground potential of the external circuit. That is, any pair of contact areas 1
Even if 3, 14 are used, one contact area is connected to ground potential. Therefore, for example, the contact region 14 is used as the ground potential,
A configuration in which one contact region 14 of each pair of contact regions is electrically connected in common may be employed. Such a configuration example is shown in FIG.

The shape of the connection region is such that a conductive film is formed on the entire seating surface 6, and the film is processed by laser to form the contact regions 13, 14 and the connection lines 15, 16 and the like. Another advantage is that the laser processing time can be reduced. This is because the area of the conductive film to be removed by laser processing can be small. FIG. 3 is a perspective view showing another embodiment of the sensor line. The sensor line 12 described with reference to FIG. 1 has its upper side in contact with the cutting edge ridge 9, and extends parallel to the cutting edge ridge 9 with a width W so as to surround the corner portion 10. On the other hand, the sensor line 123 in FIG. 3 has a width X (W> X) and is a line narrower than the sensor line 12. The sensor line 123 is also formed of a conductive film and is insulated from the base material 2 similarly to the sensor line 12. The sensor line 123 extends parallel to the cutting edge 9 so that a lower side thereof, that is, a side 124 farther from the cutting edge 9 is at a distance W from the cutting edge 9.

This distance W, like the width W of the sensor line 12 described with reference to FIG. Accordingly, as the operating time of the cutting edge 9 increases, the flank 8 wears from the cutting edge 9 side, and eventually reaches the sensor line 123 and the lower side 124 thereof.
Then, the sensor line 123 is disconnected. As described above, the sensor line 123 may be configured such that the side (lower side) 124 on the side far from the cutting edge 9 is separated from the cutting edge 9 by a predetermined distance W.

FIG. 4 is a perspective view showing still another embodiment of the sensor line. The sensor line 125 shown in FIG.
Is a plurality of, for example, three lines 12 extending in parallel.
6, 127, 128. The distance from the cutting edge 9 to the lower side of the line 128 farthest away is W. This W is a value equal to the width W of the sensor line 12 described in FIG.

When the sensor line 125 is constituted by a plurality of lines 126, 127, 128 extending in parallel in this manner, the wear is caused by the wear from the sensor line closer to the cutting edge 9 in accordance with the progress of wear of the flank surface 8. Disconnection occurs. Therefore, it is possible to detect stepwise how much the cutting edge 9 of the corner portion 10 used for cutting has worn.

In FIGS. 1, 3 and 4, the distance W from the cutting edge 9 to the lower side of the sensor line is equal to the life reference amount of the corner portion 10 (the wear limit of the flank 8). Has been described. However, the dimension W may not be a wear limit of the flank 8 but may be a dimension related to the wear of the flank 8. For example, in the case of preliminary cutting (rough cutting) or standard cutting, the wear limit of the flank 8 is relatively large.
In finish cutting, when the flank 8 wears to some extent,
Need to replace the indexable insert. In accordance with such a situation, the dimension W may be used as a throw-away tip, but may be a dimension that can detect wear to such an extent that it cannot be used for finish cutting.

FIG. 5 is an illustrative perspective view showing the manner in which the indexable insert 1 shown in FIGS. 1A and 1B is mounted on a holder. A tip mounting pocket 21 is formed at the tip of the holder 20. The bottom surface of the pocket 21 is a chip seat 22. The side surface of the pocket 21 abuts against the side surface of the chip, and a restraining surface 23 for restraining the chip.
It has become. The indexable tip 1 is accommodated in the pocket 21, and the seating surface 6 is in contact with the tip seat 22. In addition, the side surface is in contact with the constraint surface 23. Then, a clamp screw 24 is inserted into the clamp hole 11 of the throw-away tip 1 from above, and the tip thereof is inserted into the tip seat 22.
Is screwed into a screw hole 25 formed at the center of the screw. Thereby, the indexable tip 1 is mounted on the holder 20.

The tip seat 22 has a pair of probes 26 at positions facing the contact areas 13 and 14 connected to the sensor line 12 provided in the corner portion 10 used for cutting the mounted throw-away tip 1. , 27 are projected. The probes 26 and 27 are elastically urged upward and project from the tip seat 22 by, for example, several mm. When the throw away tip 1 is attached to the pocket 21,
The probe 2 is moved by the seating surface 6 of the indexable tip 1.
6 and 27 are pushed down, and the upper ends thereof are flush with the chip seat 22. At this time, the upper ends of the probes 26 and 27 are in contact with the contact area 1 provided on the seating surface 6 of the throw-away tip 1.
3 and 14 are in electrical contact with each other.

As shown by a dashed line, a lead 28 laid in the holder 20 is connected to the probes 26 and 27, and the lead 28 is connected to a resistance detection circuit 29 such as an ohmmeter. ing. Therefore, the detection circuit 29
Thereby, the resistance value of the sensor line 12 provided in the corner portion 10 used for cutting the throw-away tip 1 mounted in the pocket 21 can be measured.

When the throw-away tip 1 is mounted in the pocket 21, almost the entire surface of the seating surface 6 of the throw-away tip 1 is in close contact with the tip seat 22. For this reason, even if a cutting fluid (water or oil) is applied to the tip of the holder 20 during cutting, or the chips shaved by the throw-away tip 1 scatter around the throw-away tip 1, Cutting fluid and chips are kept in close contact with the tip seat 22
And the seating surface 6 does not enter. That is, the seating surface 6 and the tip seat 22 of the throw-away tip 1 are protected from cutting fluid and chips. Therefore, the probes 26 and 27 provided on the tip seat 22 and the contact areas 13 and 14 provided on the seating surface 6 maintain a good electrical connection even during cutting.

Further, the probes 26, 26 and the lead wires 28 connected thereto can be provided in the holder 20. The holder 20 shown in FIG. 5 is merely an example, and as a holder to which the throw-away tip 1 according to this embodiment can be mounted, for example, a prior application (Japanese Patent Application No. 11-277548) of the present applicant is used. May be used.

FIGS. 6A, 6B, 6C, 6D, and 6E show examples of various shapes of a throw-away tip to which the present invention can be applied, respectively, by a plan view and a front view (front side view). FIG. 6A shows a throw-away tip having the shape described in FIG. 1 and having a substantially square planar shape of the base material. FIG. 6B is a throwaway insert having a base material having a regular triangular planar shape, and this insert can be used for cutting at three corners on each of an upper surface and a lower surface. That is, there are a total of six corners, each provided with a sensor line, and the seating surface provided with a contact area corresponding to each sensor line.

FIG. 6C shows a chip whose base material has a rhombic planar shape. In the indexable insert shown in FIG. 6C, four acute corners located in diagonal directions are used for cutting.
FIG. 6D is a throw-away chip formed of a base material having a regular triangular shape as in FIG. 6B. The throw-away tip of FIG. 6D has a plurality of sensor lines as in the case of FIG.

6E is different from FIGS. 6A to 6D in that a so-called positive type is a throw-away insert in which only one side is used for cutting. This chip has a rake surface on the upper surface and a seating surface on the lower surface, and cannot be used upside down. The three corners on the upper surface are used for cutting. Therefore, sensor lines are provided at the three corners. A contact area is provided on the seating surface on the lower surface, and a connection line is provided on the flank on the side surface.

In addition to the shapes described above, the present invention can be applied to, for example, a throw-away tip having a round or elliptical planar shape. Next, the base material of the throw-away tip according to the present invention and the materials and manufacturing method of the sensor line, the contact area, the connection line, and the like will be described. (1) Type of base material The material of the indexable insert base material is alumina sintered body, silicon nitride based sintered body, cermet, cemented carbide, cubic boron nitride based sintered body (cBN / cubic Boron Nitride). ),
A diamond sintered body (PCD / Polycrystalline Diamond) or the like can be used.

(2) Base Material Composition and Manufacturing Method Hereinafter, a base material composition suitably used in the present invention and a manufacturing method thereof will be described. Alumina-based sintered body As the alumina-based sintered body, 2 to 30% by weight of ZrO ₂ , 0.01 to 5% by weight of at least one of oxides of Fe, Ni, and Co, and the remainder being Al ₂ O ₃ And an alumina-based sintered body composed of unavoidable impurities can be used. A
Fe as a third component to l ₂ O ₃ -ZrO ₂ system, Ni, C
By containing at least one of the oxides of o in a specific range and densifying it by hot isostatic firing, the fracture toughness can be significantly improved.

The method for producing this alumina-based sintered body is as follows.
After forming a mixed powder comprising 10 to 20% by weight of O ₂ , 0.2 to 2% by weight of at least one of oxides of Fe, Ni and Co and the balance being Al ₂ O ₃ and unavoidable impurities, The molded body is fired at 1400 to 1500 ° C and further hot isostatically fired at a temperature of 1300 to 1500 ° C to obtain a sintered body having a strength of 110 kg / mm ² or more.

As the third component, at least one of oxides of Co, Ni and Fe is contained at a ratio of 0.2 to 2% by weight. When the content is less than 0.2% by weight, improvement in fracture toughness cannot be obtained, and when it exceeds 2% by weight, the transverse rupture strength decreases. The amount of ZrO _{2 in} the sintered body is 10 to 20.
% By weight, especially 15 to 20% by weight. If the amount of ZrO ₂ is below 10 wt% ZrO ₂ less energy absorption of the crack tip by the addition, little improvement in toughness. On the other hand, if it exceeds 20% by weight, monoclinic ZrO ₂ of the ZrO ₂ crystal phase in the sintered body
The amount of ₂ (m-ZrO ₂ ) increases, and the amount of ZrO ₂ involved in energy absorption at the crack tip substantially decreases, and the fracture toughness decreases.

Furthermore, the ZrO ₂ crystal phase in the sintered body is monoclinic ZrO ₂ (m-ZrO _{2) of the} total amount of ZrO _2.
2 ) is preferably 50% or less, particularly preferably 30% or less. If it exceeds 50%, the fracture toughness is significantly reduced. The other crystal phase is tetragonal ZrO ₂ (t-ZrO ₂ ) or cubic ZrO ₂ (c-ZrO ₂ ). By containing 50% or more of these, t-ZrO ₂ → m-
ZrO ₂ or c-ZrO ₂ → t-ZrO ₂ → mZ
Due to the rO ₂ phase transition, the energy at the crack tip is effectively absorbed.

The particle size of each crystal in the alumina sintered body
Is Al_TwoO_ThreeCrystals of 1 μm or less, ZrO_Two1 μm crystal
Or less, especially 0.5 μm or less, which is larger than these values
In any case, the bending strength decreases. This alumina
As a method of manufacturing a sintered body, A having an average particle diameter of 1 μm or less is used.
l_TwoO _ThreeAgainst ZrO_Two10 to 20% by weight,
Co, Ni, Fe oxides or oxides by firing
0.2 to 2% by weight of oxides of variable compounds
Weighed and mixed in proportions, and mix
Mix and crush with the quality. After crushing, it is
After shaping, bake.

The firing method is as follows: first, firing at atmospheric pressure in the air, firing at 1400-1500 ° C. by hot pressing, and then hot isostatic firing at 1300-1500 ° C. Silicon nitride based sintered body As the silicon nitride based sintered body, silicon nitride is 85 to 96 mol%, Group 3a element of the periodic table is 1 to 5 mol% in terms of oxide, and impurity oxygen is in terms of SiO ₂ . 3 to 10 mol%, and the content of aluminum compound is oxide (A
1% by weight or less in terms of l ₂ O ₃ ). here,
The impurity oxygen is the remaining oxygen obtained by subtracting the oxygen mixed as the Group 3a element oxide of the periodic table from the total oxygen content in the sintered body, and most of the oxygen is the impurity oxygen in the silicon nitride raw material powder or the added oxygen. Oxygen in the silicon oxide.

If the amount of silicon nitride is less than 85 mol% or the amount of the oxide of the Group 3a element of the periodic table in terms of oxide is more than 5 mol%, the hardness of the sintered body is reduced. 96 mol% silicon nitride
The amount of the oxide of the Group 3a element in the periodic table is 1
If the amount is less than mol%, a dense body cannot be obtained and the strength of the sintered body decreases. On the other hand, silicon oxide of impurity oxygen (SiO ₂ )
If the conversion amount is more than 10 mol%, the toughness is reduced and the fracture resistance is reduced. If the amount of impurity oxygen is less than 3 mol%, a dense body cannot be obtained, and the strength of the sintered body decreases. And when the amount of the aluminum compound is more than 1% by weight,
The reaction resistance to cast iron deteriorates, and the wear resistance during high-speed immediate cutting deteriorates.

Desirable compositions of the sintered body are as follows: 88 to 95 mol% of silicon nitride, 2 to 5 mol% of Group 3a element of the periodic table in terms of oxide, and 2 to 5 mol% of impurity oxygen in terms of silicon oxide.
The content is preferably in a ratio of ８8 mol%. The amount of the aluminum compound is preferably 0.5% by weight or less, particularly preferably 0.3% by weight or less in terms of oxide. In addition, as elements of Group 3a of the periodic table, Y, Sc, Yb, Er, D
y, Ho, Lu and the like. Among them, Er, Y
b and Lu are good.

The silicon nitride-based sintered body is composed of a silicon nitride crystal phase and a grain boundary phase containing a Group 3a element of the periodic table, silicon, nitrogen, and oxygen. At this time, it is important that the lattice constant of the silicon nitride crystal phase is 7.606 angstroms or less on the a-axis, particularly 7.602 angstroms or less, and 2.910 angstroms or less on the c-axis, particularly 2.908 angstroms or less. this is,
7.606 angstroms for a-axis, 2.910 for c-axis
If each is greater than Angstroms, the ionic bond of silicon nitride increases and the bond strength of silicon nitride decreases, reacting easily with the work material during cutting, so-called diffusion wear increases and wear resistance deteriorates. It is. The silicon nitride crystal phase exists as a β-type needle-like crystal and has a minor axis of 0.1.
The average aspect ratio (major axis / minor axis) is 2 to 3 μm.
10 particles.

The grain boundary phase may be amorphous, but is preferably crystallized. As the crystal phase, apatite, YAM, wollastonite, disilicate and monosilicate are preferred. Further, to the silicon nitride sintered body, an appropriate amount of a metal of Group 4a, 5a or 6a of the Periodic Table such as W, Mo, Ti, Ta, Nb or V, or a carbide, nitride or silicide thereof is added. Or SiC etc.
It is also possible to add an appropriate amount of dispersed particles or whiskers to the sintered body to improve the characteristics as a composite material.

As a method for producing a silicon nitride sintered body, first, a silicon nitride powder is used as a main component as a raw material powder. Silicon nitride powder is itself α-Si ₃ N ₄ , β-Si
It can be used in any of the ₃ N _4. Their particle size is preferably from 0.4 to 1.2 μm. Next, an oxide of a Group 3a element of the periodic table and a silicon oxide powder are used as additional components, and these are appropriately weighed and mixed and pulverized by a ball mill or the like. These include, in a compact before sintering, 1 to 5 mol% of a Group 3a element oxide of the periodic table and 3 to 10 mol of silicon oxide.
The aluminum compound is mixed so as to have a mole% ratio, and the aluminum compound is not substantially added. Even if the aluminum compound is mixed into the compact as an impurity, it is controlled to be 1% by weight or less in terms of oxide.
Note that silicon oxide includes an amount obtained by converting impurity oxygen in silicon nitride powder into silicon oxide. Therefore, the starting composition is determined in consideration of mixing of the aluminum component from the ball mill or the like during mixing and pulverization and oxygen content due to oxidation.

The molded body can be obtained by molding the mixed powder into a throw-away chip base material by, for example, press molding, casting, extrusion molding, injection molding, cold isostatic pressing, or the like. The obtained molded body is fired by, for example, a hot pressing method, a normal pressure firing method, or a nitrogen gas pressure firing method. ), Immersing the molded body in a glass bath, forming a glass seal on the surface, and performing the above-described HIP treatment to achieve densification. If the firing temperature at this time is too high, the solid solution of aluminum in the silicon nitride crystal, which is the main phase, is promoted, or the grains grow and the strength decreases, and the production equipment becomes expensive.
The firing is preferably performed in a non-oxidizing atmosphere containing nitrogen gas at 50 to 2000 ° C, particularly 1700 to 1950 ° C.

Cermet The cermet contains 50 to 80% by weight of Ti, in terms of carbide, nitride or carbonitride, and 10 to 40% by weight, in terms of carbide, of a Group 6a element of the periodic table. (Hard carbon phase component having an atomic ratio of 0.4 to 0.6 in the range of 0.4 to 0.6) and 10 to 30 weight% of a binder phase component composed of an iron group metal. After the compact was placed in a vacuum furnace, the temperature was raised, and the temperature was raised to 1 to 30 at or above the liquid phase appearance temperature of the iron group metal.
A nitrogen gas at a pressure of Torr was introduced, and after reaching the maximum sintering temperature, the nitrogen gas pressure was reduced and sintering was performed. It is possible to obtain a TiCN-based cermet having a modified portion having higher toughness and higher hardness than the inside in the surface layer portion up to 1000 μm from the surface below.

The TiCN-based cermet contains 50% of Ti as a hard phase component in terms of carbide, nitride or carbonitride.
To 80% by weight, especially 55 to 65% by weight,
An element of Group 6a in the periodic table such as Mo is contained in an amount of 10 to 40% by weight, particularly 15 to 30% by weight in terms of carbide. At this time, if the amount of Ti in the hard phase component is less than 50% by weight, the abrasion resistance decreases, and if it exceeds 80% by weight, the sinterability decreases, which is not preferable. The group 6a element is
It has the effect of suppressing grain growth and improving the wettability with the binder phase. However, if it is less than 10% by weight, the above effects cannot be obtained, the hard phase becomes coarse, and the hardness and strength decrease. On the other hand, if it exceeds 40% by weight, an unhealthy phase such as an η phase is generated and sintering becomes difficult.

In addition to the above, Ta and Nb are used as hard phase components for the purpose of improving crater wear resistance, and Zr, V and Hf are used for the purpose of improving plastic deformation resistance. It is also possible to include 5 to 40% by weight as a material. However, if it exceeds 40% by weight, deterioration of wear resistance and generation of pores and voids tend to increase remarkably, which is not preferable.

On the other hand, the binder phase is mainly composed of an iron group metal such as Fe, CO, and Ni, and may partially include a hard phase forming component. The hard phase component as a whole of the sintered body is 70 to 90% by weight, and the binder phase component is 10 to 30% by weight. A major feature of the cermet used as the base material of the present invention is that the atomic ratio represented by (nitrogen / carbon + nitrogen) in the hard phase component is 0.4 to 0.6,
In particular, it is set in the range of 0.4 to 0.5.
If this atomic ratio is less than 0.4, improvement in toughness and wear resistance cannot be expected. On the other hand, if it exceeds 0.6, pores and voids are generated in the sintered body, and the reliability as a throw-away chip is reduced.

The feature of this cermet is that despite the large amount of nitrogen as described above, pores and voids do not substantially exist inside, and the burnt surface of the sintered body is very smooth. The maximum surface roughness is 3.5μm or less, and the effect of improving toughness, abrasion resistance and heat resistance can be maintained for a long period of time. As a throw-away tip, long life and high reliability can be achieved. It is to become. Moreover, without performing a polishing step or the like on the sintered body after sintering,
It can be commercialized.

The production method of the TiCN-based cermet is such that Ti is 50 to 80% by weight in terms of carbide, nitride or carbonitride, and 10 to 40% by weight of Group 6a element in the periodic table in terms of carbide. And 70 to 90% by weight of a hard phase component having an atomic ratio of (nitrogen / carbon + nitrogen) in the range of 0.4 to 0.6, and 10 to 30% by weight of a binder phase. Create a compact.

Specifically, TiC, Ti
N, TiCN, etc .;
After blending 2C, MoC, etc., or their composite carbides and composite carbonitrides, to obtain the above composition,
Molding is performed by known molding means, for example, press molding, extrusion molding, casting molding, injection molding, cold isostatic molding, or the like. At this time, as described above, it is of course possible to use a combination of carbides, nitrides, carbonitrides, and the like such as TA, Nb, Zr, V, and Hf. When TiC is used as the Ti-based material, sinterability is reduced, and partial grain growth may occur. Therefore, Ti (CN) or a combination of Ti (CN) and TiN is more preferable.

The obtained compact is set in a vacuum furnace and transferred to firing. Specifically, heating is performed in a vacuum furnace of 0.5 Torr or less, and nitrogen gas at a pressure of 1 to 30 Torr is introduced at a predetermined time. The introduction of the nitrogen gas suppresses the thermal decomposition of nitrides such as TiN contained in the compact,
This is to prevent the generation of pores and voids due to thermal decomposition. In firing, the timing of introducing the nitrogen gas is particularly important. The reason for this is that the densification usually starts around the liquid phase appearance temperature of the iron group metal in the temperature rising process, and the densification is higher than this liquid phase appearance temperature, especially 5% or more than the theoretical density ratio of the initial compact. Introduce at the stage. At the stage of densification of 5% or more, a film is formed on the surface of the molded body by a liquid phase. By introducing nitrogen gas after this film formation,
This is for preventing the nitrogen gas from remaining in the voids existing in the molded body, resulting in the formation of pores and voids.

However, when the nitrogen gas introduction timing exceeds the theoretical density ratio of about 90%, the effect of suppressing the decomposition of nitride is not substantially obtained, and the surface of the sintered body is easily roughened. % Is desirably introduced at the stage of the density. After the temperature in the furnace reaches the maximum sintering temperature, the nitrogen gas is baked while reducing the pressure of the nitrogen gas from the previously set pressure and returning to a vacuum or gradually decreasing the pressure. This is because if the pressure is further increased after reaching the maximum sintering temperature, a brittle nitride layer is formed on the surface of the sintered body that is coarse and contains almost no metal, causing a roughened surface of the burnt surface and reducing the toughness of the surface. This is because it significantly lowers.

The nitrogen gas pressure is set to 1 to 30 Torr.
The reason for limiting to r is that when less than 1 Torr, the effect of suppressing decomposition of nitrides cannot be obtained, and when it exceeds 30 Torr, sinterability is reduced and free carbon may be precipitated, and the toughness of the sintered body is reduced. It is. By such a manufacturing method, pores and voids in the sintered body can be substantially eliminated, and the surface state can be made smooth. Further, according to this manufacturing method, as described above, it has a unique property that a modified portion having high hardness and high toughness is formed on the surface layer of the sintered body.

In addition, a base material having various shapes can be formed by the cermet, but it is desirable to control a shrinkage speed during sintering as the shape becomes complicated. The reason for this is that, due to the difference in the shrinkage curves of the compacts, fine pores and cracks may be generated on the surface of the final sintered body as the shape of the compacts becomes complicated.
In order to prevent such a phenomenon, it is necessary to slow down the shrinkage speed during sintering. Therefore, by introducing an inert gas such as He or Ar beforehand when introducing the nitrogen gas, it is possible to suppress the decomposition of the nitride and to make the contraction proceed smoothly without impairing the sintering property. it can. This inert gas is introduced at a temperature approximately 50 to 200 DEG C. lower than the nitrogen gas introduction temperature. The pressure is
It is desirable that the pressure be 1 atm or less.

Cemented Carbide Cemented carbide is composed of a hard phase and a binder phase. The hard phase is tungsten carbide or tungsten carbide 5 to 5.
15% by weight is replaced with a carbide, nitride or carbonitride of a Group 4a, 5a or 6a metal of the periodic table. When components other than tungsten carbide are blended, the hard phase is W
It comprises a C phase and a composite carbide solid solution phase or a composite carbonitriding solid solution phase. The binder phase is mainly composed of an iron group metal such as Co, and Co is contained in a total amount of 5 to 15% by weight.

The cemented carbide preferably used is the above-mentioned hard metal.
Composed of cobalt tungsten carbide in addition to phase and binder phase
Preferably, a phase is present. This cobalt tungsten charcoal
As a compound, Co_ThreeW_ThreeC, Co₆W₆C, Co_TwoW
_FourC, Co_ThreeW₉C_FourAre known. these
In the X-ray diffraction curve of cobalt tungsten carbide
The largest peak is Co_ThreeW_ThreeIn C, (333) and (51)
Synthetic peak of 1), Co ₆W₆In C, (333) and (5
11) Synthetic peak, Co_TwoW_FourIn C, (333)
Synthesized peak of (511), Co_ThreeW₉C_FourThen (30
1) but these cobalt tungsten carbides
Of the peaks, the peak height with the highest intensity is I1,
The (001) peak of WC, which is the maximum peak of tungsten
When the peak height is I2, the peak represented by I1 / I2
The intensity ratio is greater than 0 and less than or equal to 0.15, preferably 0.1.
It is important that it is between 01 and 0.10. Peak intensity ratio
Is set in the above range when the intensity ratio is 0.
No precipitation of cobalt tungsten carbide in the alloy
This is because the wear resistance of the material is reduced, and exceeds 0.15.
And excessive cobalt tungsten carbide precipitates,
This is because gold strength is reduced.

The cobalt tungsten carbide phase desirably exists in the alloy as a phase having an average particle size of 5 μm or less, particularly 3 μm or less. This is because, when the average particle size exceeds 5 μm, the strength of the entire alloy is reduced because cobalt tungsten carbide is inherently brittle. Optimally, the average particle size is 2 μm or less. Further, with the formation of the cobalt tungsten carbide phase, the binder phase C
Although the lattice constant of Co fluctuates due to the solid solution of W in o, the lattice constant of Co in the cemented carbide is desirably in the range of 3.55 to 3.58.

In producing the cemented carbide, one or two or more selected from WC powder, carbides, nitrides and carbonitrides of metals of Groups 4a, 5a and 6a of the periodic table are used as raw material powders.
The above-mentioned kinds of powder and Co powder are weighed in the amounts described above, mixed and pulverized, molded by a known molding method such as press molding, and then fired. The firing is performed at a degree of vacuum of 10 ^-1 to 10 ^-3 T
1 in a temperature range of 1623 to 1773 K in a vacuum of orr
Perform for 0 minutes to 2 hours. In addition, the precipitation of cobalt tungsten carbide is performed based on the total amount of carbon including the amount of carbon in the primary raw material and the amount of carbon powder added, and carbides of metals belonging to Groups 4a, 5a, and 6a of the Periodic Table that substitute a part of tungsten carbide. , Nitride,
It can be controlled by the amount of carbonitride added. For example, when the carbon content of the raw material used is lower than the stoichiometric composition, the carbon tends to precipitate.

By precipitating a very small amount of cobalt tungsten carbide as a cemented carbide, excellent cutting performance can be obtained especially when cutting stainless steel. This is because the cobalt tungsten carbide itself has high hardness and thus has excellent wear resistance. Further, the amount of carbon dissolved in the binder phase decreases and the amount of W solid solution increases with the formation of the cobalt tungsten carbide. Is strengthened by solid solution.
Further, since the coefficient of thermal expansion of the formed cobalt tungsten carbide is different from that of the WC phase which occupies most of the alloy, a residual compressive stress is generated and the fracture resistance is also improved.

(3) Conductive Film of Sensor Line and the Like The sensor line formed on the flank of the base material of the throw-away tip itself has a predetermined electric resistance value. By measuring the change in the electric resistance value with an ohmmeter, it is possible to detect the degree of wear of the throw-away tip and the presence or absence of a defect.

The sensor lines are Ti, Zr, V, Nb,
Group 4a, 5a, 6a metals such as Ta, Cr, Mo, W, C
o, a metal material such as Ni, Fe, or a metal material such as Al, TiC, VC, NbC, TaC, Cr ₃ C ₂ , M
o ₂ C, WC, W ₂ C, TiN, VN, NbN, Ta
N, CrN, TiCN, VCN, NbCN, TaCN,
It is formed of carbides, nitrides, carbonitrides, (Ti, Al) N, etc. of metals belonging to groups 4a, 5a and 6a such as CrCN.

Among them, TiN has a strong bonding force to the base material of the throw-away tip, does not react with the work material, the electrical resistance value of the sensor line always shows a predetermined value, the degree of wear of the throw-away tip, It can accurately detect the presence or absence of defects, can effectively prevent the formation of scratches due to reaction products on the work surface of the work material, has excellent oxidation resistance, It can be suitably used for the reason that there is no change in the electric resistance value and the degree of wear of the throw-away tip and the presence / absence of occurrence of chipping can be accurately detected.

The sensor line is made as follows. First, a conductive film is deposited to a predetermined thickness on the flank of the base material of the throw-away chip by employing a PVD method such as a CVD method, ion plating, sputtering, or vapor deposition, or a plating method. Thereafter, the conductive film is processed into a predetermined pattern by laser processing or etching. A specific method for forming the sensor line is as follows.

For example, the sensor line is made of TiN,
When formed by employing the CVD method,
The temperature of the base material of the indexable insert is 900 ° C to 10 ° C.
It is placed in a heat-resistant alloy reaction vessel set at 50 ° C. and a pressure of 10 to 100 kPa. Next, 1 to 5 ml / min of TiCl ₄ and 20 to 30 H ₂ were introduced into the reaction vessel.
1 / min, the the N ₂ 10~201 / min was flowed for 20 minutes, to form a reaction product of TiN and HCl, depositing the TiN on the base metal surface of the indexable insert.

Further, (Ti, Al) N or (Ti, A) is formed by ion plating which is one of the PVD methods.
1) When forming a sensor line composed of CN, for example, a base material of a throw-away tip and a Ti-Al alloy as a cathode electrode (evaporation source) are placed in an arc ion plating apparatus. Next, the inside of the apparatus is 1 × 10 ^−5.
After heating to 500 ° C. while maintaining the torr vacuum,
Ar gas was introduced into the apparatus and 1 × 10 ⁻³ torr of Ar was introduced.
Atmosphere. Then, in this state, the base metal is -800 V
Is applied, and the surface of the base material is cleaned by Ar gas bombardment. Finally, nitrogen gas or nitrogen gas and methane gas are introduced into the apparatus as a reaction gas, and 5 ×
A reaction atmosphere of 10 ⁻³ torr and a bias voltage applied to the base material were reduced to −200 V to generate an arc discharge between the cathode electrode and the anode electrode.
The Ti-Al alloy released from the cathode electrode is reacted in a reaction atmosphere to produce (Ti, Al) N or (Ti, Al)
It is made to be CN, and is adhered to the base material surface.

The conductive film such as TiN, (Ti, Al) N, (Ti, Al) CN adhered to the surface of the base material of the throw-away chip is subjected to laser processing, etching or the like to form a sensor line, a contact area, It is processed into a predetermined pattern such as a connection line. For example, when processing into a predetermined pattern by laser processing, a YAG laser having a wavelength of 1.06 μm is applied to TiN or the like deposited on the surface of the base material at 35 kHz and 35 kHz.
50A width at 10A output, drawing speed 100-30
By scanning at 0 mm / s or CO2
₍₂₎ Irradiation scanning is performed by using a laser at an output of 20 W at an irradiation area diameter of 0.3 mm and a drawing speed of 0.3 m / min.

If the conductive film has a thickness of less than 0.05 μm, the bonding to the base material surface is weakened and the electric resistance of the sensor line is increased. There is a danger that detection will be difficult. Further, when an attempt is made to form a conductive film exceeding 20 μm, a large stress is generated inside the conductive film at the time of formation, and the intrinsic stress weakens the bonding of the conductive film to the base material surface. There is a risk. Therefore, the conductive film has a thickness of 0.05 to 2
It is preferably in the range of 0 μm, and most preferably 0.1 to
It is good to set it in the range of 5 μm.

For the sensor line and the like, the base material of the throw-away tip is an alumina sintered body, a silicon nitride sintered body, cBN
When it is formed of an insulating material such as the above, it is formed directly on the surface thereof. When the base material is formed of a conductive material such as a cemented carbide or a cermet, the base material is formed with an intermediate layer made of an insulating material such as alumina interposed therebetween. The intermediate layer made of an insulator such as alumina serves to electrically isolate the sensor lines and the like. The intermediate layer is formed to a predetermined thickness between the base material surface and the sensor line or the like (conductive film) by employing a method such as a CVD method.

The specific method of forming the intermediate layer is as follows. When the intermediate layer is made of alumina, the base material of the throw-away chip is
It is placed in a heat-resistant alloy reaction vessel set at a temperature of about 1050 ° C. and a pressure of 6.5 kPa. Next, 40 to 501 / min of H ₂ and ₁ to 31 / min of CO ₂ were introduced into the reaction vessel.
min, and the AlCl ₃ 0.5~21 / min was flowed for 2 hours, to generate a Al ₂ O _3, it is performed by depositing on the surface of the base material.

If the thickness of the intermediate layer is less than 1 μm, an electrical short circuit occurs between the base material and the sensor line and the like, and the sensor line accurately detects the degree of wear and loss of the throw-away tip. There is a risk of not being able to do so. When an intermediate layer having a thickness of more than 10 μm is to be formed, stress is generated inside the intermediate layer during the formation,
Due to the inherent stress, the bonding strength of the intermediate layer to the base material is weakened, and there is a risk that the intermediate layer is easily separated from the base material surface even when a small external force is applied. Therefore, it is preferable that the thickness of the intermediate layer be in the range of 1 μm to 10 μm.

Next, an embodiment of wear detection using the indexable insert with a wear sensor according to the present invention will be described. Example 1 An alumina sintered body was used as a base material of the throw-away tip, and the arrangement of sensor lines as shown in FIG. 1 was formed of a conductive film made of TiN. At this time,
Sensor line thickness 0.3 μm, width 0.186 μm
And The indexable insert with the wear sensor is mounted on the holder shown in FIG. 5, and a round bar-shaped workpiece made of SCM435 (chromium molybdenum steel) is continuously cut by an NC lathe under the following processing conditions, and the resistance of the sensor line is reduced. The value was measured. The results are shown in the graph of FIG.

Processing conditions: Cutting speed V = 200 m / min Depth of cut d = 2 mm Feed f = 0.2 mm / rev Wet processing Work material SCM435 (chromium molybdenum steel): round bar In the graph of FIG. The change in the measured resistance value is shown, the vertical axis shows the magnitude of the resistance value, and the horizontal axis shows the passage of time. In this graph, it can be seen that the resistance value jumps greatly 16.6 minutes after the start of processing. For reference, the damage state (wear width) of the cutting blade was measured 11 minutes and 18 minutes after the start of processing, and the result was shown as a linear broken line. This broken line indicates the change over time in the wear width at the cutting boundary.

From this measurement, 16.6 minutes after the resistance value jumped significantly from the start of processing, the sensor film width (0.186)
μm). At this point, it was clearly detected that the wear reached the use limit wear width. Example 2 The same throw-away insert as used in Example 1 was mounted on the holder shown in FIG. 5, and a four-grooved round bar-shaped workpiece made of SCM435 (chromium molybdenum steel) was used for NC.
Intermittent cutting was performed on the lathe under the above-mentioned processing conditions, and the resistance value of the sensor line was measured. The results are shown in the graph of FIG.

Machining conditions: Cutting speed V = 200 m / min Depth of cut d = 2 mm Feed f = 0.2 mm / rev Wet machining Work material SCM435 (chromium molybdenum steel): round bar with four grooves The result is 40 seconds or more The resistance jumped to infinity. Processing was stopped and the cutting edge of the indexable insert was confirmed. From this experiment, if the cutting edge became unusable due to the lack of the cutting edge,
The sensor line was also disconnected, and as a result, the defect of the cutting edge ridge of the indexable insert was clearly detected from the abnormality of the measured resistance value.

Example 3 A silicon nitride sintered body was used as a base material of a throw-away tip, and the arrangement of three parallel lines shown in FIG.
It was formed of a conductive film made of N. At this time, the thickness of the sensor line was 0.3 μm, and the width of each sensor line was 0.1
46 mm. The distance between a pair of adjacent sensor lines is 0.01 mm. This indexable insert with wear sensor is mounted on the holder shown in FIG.
A round bar-shaped workpiece made of 50 (grey cast iron) was continuously cut by an NC lathe under the following processing conditions, and the resistance value of the sensor line was measured. The results are shown in the graph of FIG. Processing conditions: Cutting speed V = 200 m / min Depth of cut d = 2 mm Feed f = 0.2 mm / rev Wet processing Work material FC250 (grey cast iron): round bar

The measured resistance value changed stepwise with the elapse of the processing time, and finally rose to infinity. For this reason, disconnection occurs in each sensor line as the wear of the chip progresses, and the resistance value increases stepwise. When the third sensor line was disconnected (about 10 minutes), the resistance value jumped to infinity, the entire sensor line was worn, and it was possible to detect that the cutting edge of the throw-away tip had reached the limit use wear width. . Although the embodiments of the present invention have been described specifically and in detail, the present invention is not limited to the embodiments, and various changes can be made within the scope of the claims.

[Brief description of the drawings]

FIG. 1A is a perspective view of a throw-away tip according to an embodiment of the present invention as viewed from above, and FIG. 1B is a perspective view of the throw-away tip as viewed from below.

FIG. 2 is a view showing a structure of a throw-away tip provided on a seating surface of the tip.
It is a top view which shows the modification of a contact area of a pair.

FIG. 3 is a perspective view showing another embodiment of the sensor line.

FIG. 4 is a perspective view showing still another embodiment of the sensor line.

FIG. 5 is an illustrative perspective view showing a manner in which the indexable insert according to the embodiment of the present invention is mounted on a holder.

FIGS. 6A to 6E are a plan view and a front view, respectively, showing examples of various shapes of a throwaway tip to which the present invention can be applied.

FIG. 7 is a graph showing test results of Example 1.

FIG. 8 is a graph showing test results of Example 2.

FIG. 9 is a graph showing test results of Example 3.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 throw-away tip 2 base material 5 rake face 6 seating face 8 flank 9 cutting edge 10 corner 12, 123, 125 sensor line 13, 14 contact area 15, 16 connection line 17 fold line 18 fold

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[Procedure amendment]

[Submission date] December 3, 1999 (1999.12.
3)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 9

[Correction method] Change

[Correction contents]

FIG. 9

Claims (6)

[Claims] 1. A base material having a substantially flat shape, a rake face on one surface of the base material, and a seating surface on the other surface of the rake face and back to back.
And a flank formed on a side surface intersecting the rake face and the seating face, wherein the flank has a cutting edge formed by a crossing edge of the rake face and the flank. A sensor line of a conductive film extending along the blade ridge is provided in an electrically insulated state with respect to the base material, and the seating surface has a pair of contacts that can be electrically connected to a predetermined circuit. A region is provided in an electrically insulated state with respect to the base material. Two connection lines respectively connecting the two contact regions and one end and the other end of the sensor line are formed on the base material surface
A throw-away tip with a wear sensor, which is provided in an electrically insulated state with respect to a base material. 2. A side edge of the sensor line remote from the cutting edge ridge extends parallel to the cutting edge ridge at a predetermined distance from the cutting edge ridge related to wear of a flank. The indexable insert with a wear sensor according to claim 1. 3. The indexable insert with a wear sensor according to claim 2, wherein the predetermined distance is equal to a life due to wear of the flank. 4. The base material is formed of an insulator, and substantially the entire surface of the base material is covered with a conductive film, and the sensor lines, the connection lines, and the contact areas are formed of a conductive film on the surface. 4. The indexable tip with a wear sensor according to claim 1, wherein the tip is formed by electrically separating the tip. 5. The base material is formed of a conductive material, substantially the entire surface of the base material is covered with a non-conductive film, and a conductive film is further formed thereon. 4. The throw-away tip with a wear sensor according to claim 1, wherein the connection line and the contact area are formed by electrically separating a conductive film on a surface. 6. The wear according to claim 4, wherein the processing for electrically separating the sensor line, the connection line, and the contact area from the conductive film on the surface of the base material is performed by laser processing. Indexable tip with sensor.