JP2005131740A - Cutting tool and cutting work method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a long service life cutting tool causing little chipping and abrasion by realizing superior work surface roughness even in extremely small inner diameter work, and an inner diameter working method using this cutting tool. <P>SOLUTION: This cutting tool 1 is formed by installing the rear end side of a tip 2 in a tool holder 3 for performing cutting by a cutting edge 5 formed in a tip projecting part 4 of the tip 2, by projecting the tip of a throw-away tip 2 composed of a sintered alloy including iron group metal at a rate of 5 mass% or more from the tip of the tool holder 3. The cutting tool comprises an electromagnetic coil 8 for magnetizing and demagnetizing the tip 2 on the tip side from a holder restricting part 6 in the tool holder 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cutting tool in which a throw-away tip made of a sintered alloy is mounted on a tool holder, and a cutting method using the cutting tool.

  Conventionally, a method for discharging machining waste generated during cutting has been widely recognized as a major factor related to cutting. Generally, the machining waste generated by the cutting edge is directed to the rake face following the cutting edge and is quickly discharged to the outside. However, in some cases, the machining waste extends long and bites into the cutting part. Since defects occur, a chip breaker is provided on the rake face to improve machining waste discharge.

  In recent years, with the diversification of cutting processing, depending on the cutting speed, cutting, and feeding, the shape of the processing waste may become powdery, and the dischargeability of the processing waste may deteriorate. In particular, when machining the extremely small inner diameter of the workpiece with ultra-precision accuracy, there is a problem that machining waste may remain in the inner diameter after machining, and it is difficult to remove it later.

  On the other hand, as a cutting tool for inner diameter processing, a cutting tool capable of processing a minimum inner diameter by providing a rod-like protrusion at the tip of a tool holder has been developed (see Patent Documents 1 and 2, etc.).

Furthermore, Patent Document 3 discloses that a permanent magnet is disposed in the vicinity of the tip of the chip, and cutting is performed while applying a magnetic field to the cutting surface of the workpiece and the cutting blade, thereby preventing the attachment of machining waste to the cutting surface. Is described.
JP-A-3-32504 JP-A-11-320217 JP 2001-157902 A

  However, when performing inner diameter processing using a cutting tool having a protrusion as described in Patent Documents 1 and 2, as described above, the object to be processed along with the recent downsizing and superprecision of electronic equipment. There is a tendency for the inner diameter of the workpiece to become smaller, so that the machining waste generated during machining is hard to be discharged out of the workpiece, biting into the cutting part, causing damage to the cutting edge and worsening the roughness of the machined surface As a result, there is a problem that high-precision machining cannot be performed. In particular, in deep hole drilling that does not penetrate, there is a risk that it is difficult to remove the machining waste after the machining waste remains in the workpiece and the chip is pulled out. Also, in some cases, once the machined tool is inserted into the machined inner diameter, the remaining machining waste may damage the workpiece surface and cause the machined surface to deteriorate, causing the machining to become unstable. It was one of.

  In addition, even in the method of cutting with a permanent magnet placed close to the chip of Patent Document 3 and applying a magnetic field, contact / adhesion of the processing waste to the processing surface can be prevented, but the processing waste is out of the system. However, when the processing is continued, there is a problem that the processing waste eventually bites into the processing surface.

  Therefore, the object of the present invention is to efficiently discharge the processing waste out of the system even when the processing waste is pulverized and the processing waste discharge performance is deteriorated, especially in the case of extremely small inner diameter processing, and stable cutting is continued and chipping is performed. Another object of the present invention is to provide a long-life cutting tool that is hard to wear and an inner diameter machining method using the same.

  In order to solve the above-mentioned problem, the present invention makes the tip of the tip protrude and magnetize this portion by the magnetizing means provided in the tool holder at the time of cutting or at the end of cutting, and attracts the machining waste, When the tip protrusion is moved away from the workpiece, the debris that has been demagnetized by the demagnetizing means provided on the tool holder is dropped from the insert to efficiently remove finely pulverized machining debris to the outside. It has been found that chipping and sudden chipping caused by biting of processing scraps can be suppressed and good surface roughness can be realized.

  That is, in the cutting tool of the present invention, the tip of the throw-away tip made of a sintered alloy containing an iron group metal in a proportion of 5% by mass or more is projected from the tip of the tool holder to the tip projection of the throw-away tip. In the cutting tool in which cutting is performed with the formed cutting edge and the rear end side of the throw-away tip is mounted on the tool holder, the throw-away tip is inserted into the tool holder from the tool holder restraining portion on the tip side Is provided with means for magnetizing and demagnetizing.

  The cutting tool is particularly effective when the tip protruding portion of the throw-away tip is inserted into the inner diameter of the workpiece to be processed without being left inside the processed inner diameter. is there.

  Further, the content of cobalt in the sintered alloy forming the throw-away tip is 6 to 13% by mass, while maintaining chip resistance and wear resistance of the tip as a cutting tool, and tip tip protruding portion It is desirable in terms of easy control of magnetization and demagnetization.

  Further, it is desirable that the means for magnetizing and demagnetizing the tool holder comprises an electromagnetic coil, since both magnetization and demagnetization can be performed by switching, and the magnetization can be reliably controlled with a simple structure. Further, when the throwaway tip is substantially rod-shaped, it can be magnetized and demagnetized with at least a part of the restraining portion of the throwaway tip inserted into the electromagnetic coil. Magnetization and demagnetization can be performed more reliably and easily.

In addition, if at least a part of the tip protruding portion of the throw-away tip is magnetized to a magnetic flux density of 50 × 10 ⁻⁴ T or more, the machining waste can be reliably attracted when magnetized.

  Furthermore, the cutting method of the present invention uses the above cutting tool to magnetize the throw-away tip during or after processing, and remove the throw-away tip when the throw-away tip is separated from the workpiece. This method is characterized in that magnetism is performed, and according to this method, it is possible to efficiently discharge the machining waste to the outside of the processing system and to perform cutting continuously.

  According to the cutting tool for inner diameter machining of the present invention, the tip of the tip is projected and magnetized by the magnetizing means provided in the tool holder at the time of cutting or at the end of cutting, and the work waste is attracted. When the chip tip protruding part is moved away from the workpiece, the debris that is demagnetized by the demagnetizing means provided on the tool holder is dropped from the chip to efficiently remove the finely scraped machining debris from the chip. It can be discharged, and chipping and sudden chipping caused by biting of processing scraps can be suppressed to achieve good surface roughness.

  FIG. 1 is a schematic perspective view of an example in which a throw-away tip, which is a preferred example of the cutting tool of the present invention, is mounted in a tool holder, in order to explain the application state of a magnetic field to the tip in the cutting tool of FIG. This will be described with reference to FIG.

  According to FIG. 1, the cutting tool 1 has a tip of a throw-away tip (hereinafter simply referred to as a tip) 2 made of a sintered alloy containing an iron group metal at a ratio of 5 mass% or more from a tip of the tool holder 3. Cutting is performed with a cutting blade 5 formed on the tip protruding portion 4 of the tip 2 and the rear end side of the tip 2 is attached to the tool holder 3, and the tip 2 is restrained in the tool holder 3. An electromagnetic coil 8 that magnetizes and demagnetizes from the portion 6 to the tip side is provided.

  According to the present invention, the cutting tool 1 is configured as described above, and the tip end protruding portion 4 is magnetized by applying a direct current to the electromagnetic coil 8 at the time of cutting or at the end of cutting to generate a magnetic field, and attracts machining waste. At the same time, when the chip tip protrusion 4 is moved away from the workpiece, a magnetic powder 8 is applied to the magnet coil 8 to apply a current in the opposite direction to demagnetize and attract the processed waste. Efficiently discharges machining scraps that are difficult to eject, suppresses chipping and sudden chipping caused by biting of the machining scraps, etc., and realizes good surface roughness and continuous machining. Can be done.

  Here, the cutting method of the present invention magnetizes the chip 2 during or after the processing, and demagnetizes the chip 2 when the chip 2 is separated from the work (work material). Since the machining scraps of the inner diameter machining can be adsorbed to the chip 4 and the chip 4 can be simultaneously discharged when the chip 4 is pulled out from the machining hole, the machining scrap can be efficiently discharged out of the machining hole. Further, by demagnetizing the chip 4 after discharging the machining waste, the machining waste can be removed from the chip 4, and the machining waste is processed while adhering to the chip 4, resulting in deterioration of the machined surface roughness. Sudden loss or the like can be prevented.

  Even if a magnetic field is applied during machining, the temperature of the machined surface exceeds 1000 ° C. and reaches the vicinity of the Curie point of the iron group metal. Therefore, the cutting scraps are not attracted to the cutting edge 5 by the application of a magnetic field without the cutting scraps being drawn. Furthermore, since this processed surface portion has an effect that the elution of the iron group metal as the binder phase can be prevented by being magnetized, the chip 4 having excellent wear resistance is obtained.

  Here, according to FIG. 1, the chip 2 has a substantially rod shape, and is configured to be magnetized and demagnetized with at least a part of the restraining portion 6 of the chip 2 inserted into the electromagnetic coil 8. Magnetization and demagnetization can be more reliably and easily performed by the configuration.

  On the other hand, according to the present invention, at least the protrusion 5 of the chip 4 contains an iron group metal at a ratio of 5% by mass or more, so that magnetization and demagnetization by the magnetization / demagnetization unit 20 is performed in the protrusion 5. As a result, machining waste can be discharged efficiently and stably, and even in the smallest internal diameter machining, good machining surface roughness can be achieved without being affected by machining waste. A long-lasting cutting tool that can be realized and is resistant to chipping and wear is obtained.

  In addition, the sintered alloy in the present invention has a form in which a hard phase is bonded with a bonded phase made of an iron group metal, and specifically, cemented carbide, cermet, diamond or cubic boron nitride (cBN). One kind selected from the group. Among these, it is desirable to be made of a cemented carbide in terms of ease of manufacture, cost, fracture resistance, and suitability for ultraprecision machining.

  Furthermore, the content of cobalt in the sintered alloy forming the chip 2 is 6 to 13% by mass, particularly 8 to 12% by mass, while maintaining the chipping resistance and wear resistance of the chip as a cutting tool. It is desirable because it is easy to control the magnetization and demagnetization of the tip protruding portion. It should be noted that there is no problem if the surface of the chip 2 can be magnetized and demagnetized even if a known hard coating layer or a plurality of layers are formed. In order to ensure magnetization and demagnetization, it is desirable that the film thickness of the hard coating layer at the tip end protruding portion is 10 μm or less. That is, by increasing only the thickness of the hard coating layer in the cutting blade 5, it is possible to suppress the attachment of processing waste to the cutting blade.

Here, if at least a part of the tip end projecting portion 4 is magnetized to a magnetic flux density of 50 × 10 ⁻⁴ T or more, it is possible to surely attract and attract the processing waste when magnetized, and to reliably process the chip. This is desirable because waste can be discharged out of the processing hole.

  In addition, according to this invention, when the said front-end | tip protrusion part of the said throwaway tip as shown in FIG. 1 is inserted in the internal diameter of a workpiece | work, and it processes inside diameter, it can discharge | emit without leaving a processing waste in a processing hole especially. It is particularly effective because it can be done.

  Further, in FIG. 1, the means for magnetizing and demagnetizing the tool holder 3 is composed of an electromagnetic coil 8, and both magnetization and demagnetization can be performed by switching, and the magnetization can be controlled reliably with a simple structure. Although the present invention is desirable, the present invention is not limited to this. A permanent magnet is installed in the tool holder 3, and this permanent magnet is brought close to the tip end protruding portion 4 so that the tip end protruding portion 4 is moved. It is possible to weaken the magnetic force of the tip tip protrusion 4 by magnetizing and moving the permanent magnet away from the tip tip protrusion 4. Further, as a method of demagnetization, the heater may be installed inside the tool holder 3 and magnetized / demagnetized by other means such as heating the tip end protrusion 4 to the Curie temperature or higher. You may combine a means suitably.

  In addition, by drawing the wiring from the tool holder 2 of the present invention to the processing machine, the operation of magnetization / demagnetization can be controlled from the outside of the processing machine by interlocking with the processing program, using a dedicated control device or a manual switch. Corresponding processing waste can be discharged automatically.

It is a schematic perspective view which shows an example of the cutting tool of this invention. It is a conceptual diagram for demonstrating the application state of the magnetic field to a chip | tip in the cutting tool of FIG.

Explanation of symbols

1 Cutting tool
2 Throw away tip (chip)
3 Tool holder 4 Tip tip protruding part 5 Cutting blade 6 Holder restraint part 8 Electromagnetic coil 10 Wiring

Claims (7)

The tip of the throwaway tip made of a sintered alloy containing an iron group metal in a proportion of 5% by mass or more is projected from the tip of the tool holder, and cutting is performed with a cutting blade formed on the tip projection of the throwaway tip. In addition, in the cutting tool formed by attaching the rear end side of the throw-away tip to the tool holder, the throw-away tip is magnetized and demagnetized in the tool holder from the tool holder restraining portion toward the front end side. A cutting tool comprising means. The cutting tool according to claim 1, wherein the tip protruding portion of the throw-away tip is inserted into an inner diameter of a workpiece to perform inner diameter processing. The cutting tool according to claim 1 or 2, wherein a content of cobalt in the sintered alloy constituting the throw-away tip is 6 to 13% by mass. The cutting tool according to any one of claims 1 to 3, wherein the means for magnetizing and demagnetizing the tool holder comprises an electromagnetic coil. The cutting tool according to claim 4, wherein the throw-away tip has a substantially rod shape, and is magnetized and demagnetized in a state where a rear end portion of the throw-away tip is inserted into the electromagnetic coil. The cutting tool according to any one of claims 1 to 5, wherein at least a part of the tip protruding portion of the throw-away tip is magnetized to a magnetic flux density of 50 × 10 ^-4 T or more. Using the cutting tool according to any one of claims 1 to 6, the throw-away tip is magnetized during or after processing, and the throw-away tip is demagnetized when the throw-away tip is separated from the workpiece. The cutting method characterized by performing.

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