JP2009107059A - Cutting tool, cutting insert, and method of manufacturing cutting insert - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting tool in which a positional displacement is prevented from occurring between a cutting insert and a tool holder during the cutting by stabilizing the restraint of a pressing member and the cutting insert, and also the restraint of the cutting insert and the tool holder. <P>SOLUTION: In this cutting tool 1, an inner wall 22a of a through-hole 22 is pressed against at least a retraining wall surface 30b by a pressing member 4, and the cutting insert 2 is installed on the tool holder 3. The portion of the inner wall 22a of the through-hole 22 which is pressed by the pressing member 4, has a smooth surface, and the surface roughness of the portion is made smaller than that of the portion of the side surface 21 of the cutting insert which is restrained by the restraining wall surface 30b of the tool holder 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cutting tool used for cutting a work material such as steel or cast iron by attaching one or a plurality of cutting inserts to an insert pocket of a tool holder, a cutting insert attached to the cutting tool, and the cutting The present invention relates to an insert manufacturing method.

  Conventionally, when performing cutting of steel, cast iron, etc., Ti nitride, carbide, or carbonitride, Al2O3, or a solid solution of Ti and Al on the surface of a substrate such as a WC-based cemented carbide or TiCN-based cermet There is known a technique for improving the tool life of a cutting insert by forming a coating layer of nitride, carbide, carbonitride, carbonate, or the like. In addition, a technique is known in which the cutting edge portion of the cutting insert on which the coating layer is formed is subjected to a cutting edge process such as honing or chamfering to improve the cutting edge strength and increase the tool life. Furthermore, there is known a technique for preventing chip welding and improving chip discharge during polishing by polishing the surface of the cutting blade on which the coating film has been formed, and the surface of the flank. ing.

As described above, as a technique related to a cutting insert in which a coating layer is formed on the surface of a substrate, for example, as in Patent Document 1, smoothing is performed on an upper portion of a breaker and a seating surface on which a coating layer is formed. A material that reduces the coefficient of friction and effectively suppresses the generation and propagation of thermal cracks during cutting is disclosed.
JP 2005-2504411 A

  When the above-mentioned cutting insert is restrained by pressing the inner wall of the through-hole in the side surface direction and restraining to the tool holder using a lever lock method or a cam lock method, it occurs between the cutting insert and the tool holder at the time of cutting. Positional misalignment is a problem. One of the causes is that the inner wall is rough and the inner wall is deformed by firing, so that the binding force between the inner wall and the pressing member is weakened.

  However, the misalignment that occurs between the cutting insert and the tool holder consists of two factors. That is, a positional shift that occurs between the inner wall of the cutting insert and the pressing member, and a positional shift that occurs on the side surface of the cutting insert and the constraining wall surface of the insert pocket. For this reason, in order to suppress misalignment between the cutting insert and the tool holder, it is not sufficient to improve the restraining force between the inner wall of the cutting insert and the pressing member. The binding force must also be improved.

  In view of the above problems, an object of the present invention is to improve both the restraining force between the pressing member and the inner wall during cutting and the restraining force between the side surface of the cutting insert and the restraining side surface of the tool holder. It is to provide a cutting tool in which no positional deviation occurs between the two.

  Of the present invention, the invention according to claim 1 comprises a cutting insert having a substantially flat plate shape, having a cutting edge between an upper surface and a side surface, and having a through-hole penetrating from the upper surface to the lower surface, and the cutting insert. A tool holder in which an insert pocket having a mounting surface on which the cutting insert is placed, a constraining wall surface that comes into contact with the side surface of the cutting insert, and a pressing member that presses the cutting insert against the tool holder are provided. In the cutting tool in which the inner wall of the through hole is pressed toward at least the restraining wall surface by the pressing member, and the cutting insert is restrained by the tool holder, the inner wall of the through hole is pushed by the pressing member. The pressed portion has a smooth surface, and the surface roughness of the side surface of the cutting insert is greater than the portion that is in contact with the constraining wall surface. And wherein the small.

  Moreover, it is preferable that the part pressed by the said pressing member is coat | covered with the coating layer.

  Of the present invention, the invention according to claim 3 has a substantially flat plate shape, a cutting blade is formed between the upper surface and the side surface, and has a through hole penetrating from the upper surface to the lower surface, In the cutting insert in which the inner wall of the through hole is pressed at least in the lateral direction and restrained by the tool holder, the pressed portion of the inner wall of the through hole is covered with a coating layer and has a smooth surface. The surface roughness of the side surface is smaller than that of the portion contacting the tool holder.

  Moreover, it is preferable that the said coating layer was formed into a film by the chemical vapor deposition method.

  The coating layer preferably has at least one titanium carbonitride that forms columnar crystals.

  The smooth surface is preferably formed by wet blasting.

  Among the present inventions, the invention according to claim 7 is the method for manufacturing the cutting insert according to any one of claims 3 to 6, wherein the cutting insert is outside the inner diameter of the inner wall with respect to the through hole of the cutting insert. The method comprises a step of polishing by spraying abrasive grains on the inner wall while bringing a nozzle nozzle having a small diameter close to the through hole.

  According to the cutting tool of the present invention, during the cutting process, the positional deviation that occurs between the inner wall of the cutting insert and the pressing member is suppressed, and the positional deviation that occurs between the side surface of the cutting insert and the constraining wall surface of the insert pocket. As a result, displacement of the cutting insert relative to the tool holder can be suppressed. Furthermore, damage starting from the inner wall of the through hole of the cutting insert can be suppressed.

  In the present invention, the cutting insert refers to one made of a substrate such as a WC-based cemented carbide or TiCN-based cermet, or one having a coating layer formed on the surface of the substrate.

  An embodiment of the present invention will be described below with reference to the drawings.

  FIG. 1 is a perspective view showing a first embodiment of a cutting insert according to the present invention. 2 is a perspective view of a tool holder for restraining a cutting insert according to the present invention, FIG. 3 is a plan view showing a cutting tool in which the cutting insert of FIG. 1 is attached to the tool holder of FIG. 2, and FIG. FIG. 4 is a sectional view taken along line XX in FIG. 3.

  As shown in FIG. 1, the cutting insert 2 according to the present embodiment has an upper surface 20 provided with a rake face and a side surface 21 provided with a flank face. A cutting blade 20a is formed between the rake face and the flank face. Further, a through hole 22 is provided near the center of the upper surface 20 so as to penetrate the upper surface 20 and the lower surface almost vertically.

  This cutting insert 2 is restrained by the tool holder 3 shown in FIG. An insert pocket 30 having a placement surface 30a and a restraining side surface 30b is formed at the tip of the tool holder 3, and an attachment hole 30c of the tool holder 3 is placed at the center of the placement surface 30a. It is formed substantially perpendicular to the surface 30a. Further, a screw hole 31 is formed in the vicinity of the insert pocket 30 on the upper surface proximal end side of the tool holder 3. When the cutting insert 2 is constrained to the tool holder 3, a screw member 41 described later is screwed into the screw hole 31.

  As shown in FIG. 3, the cutting insert 2 is constrained to the tool holder 3 by a pressing member 4 including a clamp lever 40 and a screw member 41. As shown in FIG. 4, among the pressing members 4, the clamp lever 40 having an L-shaped cross section is disposed inside the tool holder 3 below the insert pocket 30, and one end 40 a of the clamp lever 40 is in the insert pocket 30. It protrudes outward from the provided mounting hole 30c, and the other end 40b is disposed inside the tool holder 3. The cutting insert 2 is disposed in the insert pocket 30 so that one end 40 a of the L-shaped clamp lever 40 is inserted into the through hole 22 of the cutting insert 2. Next, the screw member 41 having a tapered portion that engages with the other end 40 b of the clamp lever 40 is screwed into the tool holder 3. At this time, the other end 40 b of the clamp lever 40 is pressed downward by the taper portion of the screw member 41 and sinks into the tool holder 3 together with the screw member 41, and one end 40 a of the clamp lever 40 is connected to the through hole 22. It moves toward the inner wall 22a. Then, one end 40a of the clamp lever 40 abuts on an intermediate region of the inner wall 22a that is substantially equidistant from the upper surface 20 and the lower surface, and presses the inner wall 22a of the cutting insert 2. As a result, the side surface 21 of the cutting insert 2 is pressed against the constraining wall surface 30 b of the insert pocket 30 and is constrained by the tool holder 3.

  As a feature of the present invention, a smooth surface is formed in a portion of the inner wall 22a of the through hole 22 that is pressed by the one end 40a of the clamp lever 40. Thereby, compared with the inner wall 22a of the conventional cutting insert 2 which had the uneven | corrugated surface with a burnt surface like the side surface 21, the inner wall 22a of the cutting insert 2 which concerns on this invention is a smoother surface by grinding | polishing. Therefore, the contact ratio between the one end 40a of the clamp lever 40 and the inner wall 22a increases, and the clamping force of the cutting insert 2 by the clamp lever 40 increases. That is, it is possible to effectively suppress the positional deviation that occurs between the clamp lever 40 and the inner wall 22a during the cutting process.

  As described above, it is possible to suppress both the positional deviation that occurs between the clamp lever 40 and the inner wall 22 a and the positional deviation that occurs between the side surface 21 of the cutting insert 2 and the constraining wall surface 30 b of the tool holder 3. For this reason, it is possible to suppress the positional deviation that occurs between the cutting insert 2 and the tool holder 3.

  Furthermore, since the inner wall 22a is polished and smooth, the stress at the time of restraint applied to the inner wall 22a from the one end 40a of the clamp lever 40 is prevented from being concentrated on one point of the inner wall 22a, and the cutting insert 2 starting from the inner wall is prevented. Breakage can be prevented.

  In the present embodiment, the inner wall 22a is covered with a coating layer harder than the base. Thereby, the intensity | strength of the inner wall 22a can be improved and the effect which prevents the failure | damage of the cutting insert 2 from the inner wall 22a can be heightened. As the coating layer, a hard film made of aluminum oxide, nitride, carbide, carbonitride, oxide, carbonate, nitride, or carbonitride of an element selected from titanium, zirconium, and hafnium is used. It is preferably used because of its excellent strength and adhesion of the film.

  Further, the cutting insert 2 according to the present embodiment has the coating layer as described above formed on the surface other than the inner wall 22a. Thereby, the intensity | strength and abrasion resistance of the surface part in which the coating layer was formed into a film are improving.

  Further, the coating layer includes titanium carbonitride forming columnar crystals. Thereby, the effect which prevents the damage at the time of restraining the cutting insert 2 to the tool holder 3 can be heightened by the high toughness of the titanium carbonitride which consists of columnar crystals.

At this time, physical vapor deposition (PVD) or chemical vapor deposition (CVD) can be used as a method for coating the cutting insert 2. In particular, it is preferable to use the chemical vapor deposition method because the coating layer can be formed with a uniform thickness on the inner wall 22a of the through hole 22 than other vapor deposition methods. In general, when a coating layer is formed by a chemical vapor deposition method, the surface of the film may be roughened due to abnormal grain growth or the like, so that the surface of the film is polished and smoothed as in the present invention. Is effective.
Further, the intermediate region of the inner wall 22a pressed by the one end 40a of the clamp lever 40 preferably has a smaller surface roughness than the other region of the inner wall 22a. Thereby, the breakage of the cutting insert 2 starting from the portion pressed by one end of the clamp lever 40 can be more effectively suppressed. The maximum height Rz of the coating layer formed on the inner wall 22a is preferably 0.5 μm or less, particularly preferably 0.2 μm or less. Here, as a method of measuring the maximum height Rz of the coating layer, it may be measured using a stylus type surface roughness measuring instrument in accordance with JIS B0601'01, and when such measurement is difficult, Measurement can be performed by using a measuring instrument such as a laser microscope or an atomic force microscope to estimate the unevenness on the surface of the coating layer while scanning. In the measurement of the maximum height Rz, when a stylus type surface roughness measuring instrument is used, the cutoff value is 0.25 mm, the reference length is 0.8 mm, and the scanning speed is 0.1 mm / second. taking measurement. Moreover, Rz is measured along the penetration direction of a through-hole also when using any measuring instrument mentioned above.

[Production method]
Below, the manufacturing method of the cutting insert which concerns on this invention is demonstrated.

  The base of the cutting insert according to the present embodiment is a hard material comprising at least one selected from the group consisting of tungsten carbide (WC) and, if desired, carbides, nitrides, and carbonitrides of Group 4, 5, and 6 elements of the periodic table. Cemented carbides whose phases are bonded with a binder phase composed of an iron group metal such as cobalt (Co) and / or nickel (Ni), Ti-based cermet, silicon nitride, aluminum oxide, diamond, cubic boron nitride, etc. It consists of one of ceramics.

  For example, in the case of using a cemented carbide as the substrate, 5-10% by mass of metallic cobalt (Co) powder, Group 4, 5, 6 elements of the periodic table are used for the tungsten carbide (WC) powder. A compound capable of forming at least one hard phase selected from the group of carbides (excluding tungsten carbide), nitrides, and carbonitrides of 0.1 to 8.0% by mass, and mixed, Molded into a cutting tool shape by press molding. And after performing a binder removal process with respect to this molded object, it baking at 1350-1550 degreeC for 0.5 to 3 hours in a vacuum, and the base | substrate which consists of a cemented carbide alloy is produced.

  Next, as shown in FIG. 5, the inner wall 22a of the through hole 22 is blasted. The processing conditions use abrasive grains of alumina # 200 to 1000, and the jet pressure is 2 to 10 MPa and the maximum height Rz is adjusted to a uniform roughness of about 0.3 μm to 1.5 μm.

  As a feature of the production method according to the present invention, the outer diameter smaller than the inner diameter of the through-hole 22 is small, the ejection nozzle 5 having the ejection port 50 at the tip is brought closer to the through-hole 22, and abrasive grains are sprayed on the inner wall 22a. Polished. Thereby, abrasive grains can be sufficiently sprayed over the entire area of the inner wall 22a, and the inner wall 22a can be polished more smoothly.

  At this time, it is preferable to use a wet blasting process in which abrasive grains are ejected simultaneously with the cooling liquid as the blasting process. This is desirable because it prevents the base from being oxidized by the heat generated during the polishing process and lowers the strength and prevents the fracture resistance from being lowered.

  When the cutting insert 2 is subjected to overall polishing such as barrel processing, not only the inner wall 22a of the through hole 22 but also the side surface 21 is polished, so that a frictional force generated between the side surface 21 and the constraining wall surface 30b is generated. descend. As a result, misalignment tends to occur between the side surface 21 of the cutting insert 2 and the constraining side surface 30 b of the tool holder 3.

  Next, a method for forming a coating layer on the inner wall 22a of the substrate using, for example, chemical vapor deposition will be described.

In this embodiment, the first layer, which is the lowermost layer, is formed on the surface of the substrate from the first layer to the sixth layer in order. As specific film formation conditions, in order to form a titanium nitride (TiN) layer, which is the first lowermost layer, 0.1 to 10% by volume of titanium chloride (TiCl ₄ ) gas as a reaction gas composition, Nitrogen (N ₂ ) gas 5-60% by volume, the remaining gas mixture consisting of hydrogen (H ₂ ) gas is sequentially adjusted to adjust the chamber temperature to 800-1100 ° C. and pressure 5-85 kPa. To do.

Next, in order to form a titanium carbonitride (TiCN) layer as the second layer, the reaction gas composition is 0.1 to 10% by volume of titanium chloride (TiCl ₄ ) gas and 0 to nitrogen (N ₂ ) gas. 40% by volume, acetonitrile (CH ₃ CN) gas is 0.3 to 2.0%, and the remaining gas mixture is hydrogen (H ₂ ) gas, and the inside of the chamber is 750 to 900 ° C., pressure Adjust to 5 to 85 kPa.

In order to form a granular TiCN layer as the third layer, the reaction gas composition is 3 to 10% by volume of titanium chloride (TiCl ₄ ) gas, 5 to 40% by volume of nitrogen (N ₂ ) gas, and methane. A mixed gas composed of (CH ₄ ) gas in an amount of 1 to 15% by volume and the remainder consisting of hydrogen (H ₂ ) gas is sequentially adjusted so that the temperature in the chamber is 950 to 1100 ° C. and the pressure is 5 to 85 kPa. .

Further, to form a TiCNO layer as the fourth layer, titanium chloride (TiCl ₄ ) gas is 0.1 to 3% by volume, methane (CH ₄ ) gas is 0.1 to 10% by volume, carbon dioxide ( A mixed gas consisting of 0.01 to 5% by volume of CO ₂ ) gas, 5 to 60% by volume of nitrogen (N ₂ ) gas, and the remaining hydrogen (H ₂ ) gas is prepared and introduced into the reaction chamber, The inside is adjusted to 800 to 1100 ° C. and 5 to 30 kPa.

In order to form the Al ₂ O ₃ layer as the fifth layer, aluminum chloride (AlCl ₃ ) gas is 3 to 20% by volume, hydrogen chloride (HCl) gas is 0.5 to 3.5% by volume, Using a mixed gas composed of 0.01 to 5.0% by volume of carbon dioxide (CO ₂ ) gas, 0 to 0.1% by volume of hydrogen sulfide (H ₂ S) gas, and the remainder consisting of hydrogen (H ₂ ) gas, It adjusts so that it may become 900-1100 degreeC and 5-10 kPa.

Finally, in order to form titanium nitride (TiN) or titanium carbide (TiC) which is the sixth layer as the outermost layer, titanium chloride (TiCl ₄ ) gas is 0.1 to 10% by volume as a reactive gas composition, and nitrided. In the case of titanium (TiN), nitrogen (N ₂ ) gas is 5 to 60% by volume, in the case of titanium carbide (TiC), methane (CH ₄ ) gas is 5 to 60% by volume, and the remainder is from hydrogen (H ₂ ) gas. The mixed gas to be adjusted is adjusted so that the temperature in the chamber is 800 to 1100 ° C. and the pressure is 5 to 85 kPa.

  By the film formation method under the above conditions, a coating layer having a uniform thickness can be formed on the inner wall 22a of the through hole 22 as compared with other vapor deposition methods.

  Next, in order to smooth the surface of the formed coating layer, the inner wall 22a of the through hole 22 is blasted. Specifically, as shown in FIG. 6, the outer diameter of the surface of the deposited coating layer 6 is smaller than the inner diameter of the through-hole 22 with respect to the inner wall 22a of the through-hole 22, and the spout is formed at the tip. The jet nozzle 5 having 50 is brought close to the through hole 22 and blasted using abrasive grains such as silicon carbide and aluminum oxide. As a result, the coating layer 6 formed on the inner wall 22a of the through hole 22 can be uniformly polished, so that the positional deviation generated between the clamp lever 40 and the inner wall 22a during cutting and the stress during restraint. The chipping of the cutting insert 2 due to concentration can be suppressed.

  It is desirable that the processing conditions be the same as in the blasting of the substrate, using alumina # 200-1000 abrasive grains, and the ejection pressure is 2-10 MPa. Further, it is desirable to use wet blasting similarly to the blasting of the substrate.

1 is a perspective view showing a first embodiment of a cutting insert according to the present invention. It is a perspective view of the tool holder which restrains the cutting insert which concerns on this invention. FIG. 3 is a plan view showing a cutting tool in which the cutting insert shown in FIG. 1 is attached to the tool holder shown in FIG. 2. It is XX sectional drawing in FIG. It is a grinding | polishing method of the through-hole inner wall of the cutting insert which concerns on this invention. This is a polishing method for a coating layer formed on the inner wall of a through hole.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cutting tool 2 ... Cutting insert 20 ... Upper surface 20a ... Cutting blade 21 ... Side surface 22 ... Through-hole 22a ... Inner wall 3 ... Tool holder 30 ... Insert Pocket 30a ... Placement surface 30b ... Wall 30c ... Mounting hole 31 ... Screw hole 4 ... Pressing member 40 ... Clamp lever 40a ... One end 40b ... Other end 41 ..Screw member 5 ... Ejecting nozzle 50 ... Ejecting port 6 ... Coating layer

Claims (7)

A cutting insert having a substantially flat plate shape, having a cutting edge between the upper surface and the side surface, and having a through hole penetrating from the upper surface to the lower surface;
A tool holder in which an insert pocket having a mounting surface on which the cutting insert is mounted and a constraining wall surface in contact with a side surface of the cutting insert is formed;
A pressing member that presses the cutting insert against the tool holder,
In the cutting tool in which the pressing member presses the inner wall of the through hole toward at least the restraining wall surface, and the cutting insert is restrained by the tool holder,
The portion of the inner wall of the through hole that is pressed by the pressing member has a smooth surface, and the surface roughness of the side surface of the cutting insert is smaller than the portion that is in contact with the constraining wall surface. Cutting tool that features.   2. The cutting tool according to claim 1, wherein the portion pressed by the pressing member is covered with a coating layer. It has a substantially flat plate shape, a cutting edge is formed between the upper surface and the side surface, and has a through-hole penetrating from the upper surface to the lower surface, and the inner wall of the through-hole is pressed at least in the side surface direction. In the cutting insert restrained by the holder,
The portion to be pressed of the inner wall of the through hole is covered with a coating layer and has a smooth surface, and the surface roughness is smaller than the portion of the side surface that contacts the tool holder. Features cutting inserts.   The cutting insert according to claim 3, wherein the coating layer is formed by a chemical vapor deposition method.   The cutting insert according to claim 3 or 4, wherein the coating layer has at least one layer of titanium carbonitride forming columnar crystals.   The cutting insert according to claim 3, wherein the smooth surface is formed by wet blasting. It is a manufacturing method of the cutting insert in any one of Claims 3-6,
Cutting comprising: a step of bringing a jet nozzle having an outer diameter smaller than the inner diameter of the inner wall toward the through hole of the cutting insert closer to the through hole, and polishing the inner wall by spraying abrasive grains. Manufacturing method of insert.

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