JP2006272520A - Magnetism-assisted processing method and magnetic tool for use in it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetism-assisted processing method and a magnetic tool for use in it capable of easily processing the inner surface of a pipe aiming at imparting compression stress, increasing hardness through work hardening and reducing frictional resistance in magnetism-assisted processing performed with the magnetic tool disposed in a variable magnetic field. <P>SOLUTION: In this magnetism-assisted processing method, the magnetic tool is disposed in a variable magnetic field, motion is given to the magnetic tool by the variation of the magnetic field to bring the magnetic tool into a collision with a workpiece. A magnetic tool to be used has at least magnetic anisotropy, and the shape of the magnetic pole end is curved by machining or resin or metal coating. The magnetic tool has the shape anisotropy, and an abrasive may be contained in resin or metal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a magnetically assisted machining method and a magnetic tool used therefor, and more specifically, for example, a clean tool used in a semiconductor industry, a chemical product analysis instrument, etc. by a magnetic tool applied in a varying magnetic field. To process pipes, various ceramic pipes, and the inner surfaces of pipes with complex shapes such as T-shaped pipes and L-shaped pipes for the purpose of applying compressive stress, increasing hardness by work hardening, reducing frictional resistance, etc. The present invention relates to a magnetically assisted machining method and a magnetic tool used therefor.

  “Magnetic Assisted Machining (Magnetic Polishing)”, which is a precision machining technology that incorporates the action of a magnetic field, is attracting attention as a new technology that is not bound by existing concepts. This magnetically assisted processing method realizes precise surface processing by applying a processing force and a kinetic force to magnetic abrasive grains and magnetic particles through magnetic lines of force. The magnetic field assisted machining method using magnetic field lines is a technology that focuses on the phenomenon of magnetic field lines passing through a non-magnetic material, similar to the X-ray object transmission phenomenon. For example, it is possible to polish the surface of a part having a complicated shape, the inner surface of a hole that does not receive a tool, the inner surface of a tube that does not reach the tool, and the like (see, for example, Patent Document 1) ).

Conventionally, in such a magnetically assisted machining method, it has been studied to arrange and process a pin-shaped magnetic tool in a variable magnetic field. However, as a conventionally used pin-shaped magnetic tool, A material obtained by cutting a wire made of a soft magnetic material such as induced martensitic stainless steel or carbon steel has been used.
JP2002-192453

  However, a pin-shaped magnetic tool obtained by simply cutting a wire has a sharp edge at the magnetic pole end. When a magnetic-assisted machining method is used with such a magnetic tool, the sharp edge shape is covered. There is a problem that the pipe inner surface, which is a processed material, is transferred as it is, and the inner surface of the pipe has an indentation formed in a V-groove shape.

  In recent years, among the polishing of precision pipes used in various industries, various demands such as applying compressive stress, increasing hardness by work hardening, reducing frictional resistance, etc., especially for internal polishing where normal polishing methods cannot be applied. However, there have been no studies to meet these demands.

  The present invention has been made in order to solve the above-mentioned problems, and its purpose is to apply compressive stress to the inner surface of a pipe, work hardening in a magnetically assisted processing performed by arranging a magnetic tool in a variable magnetic field. It is an object of the present invention to provide a magnetically assisted machining method and a magnetic tool used therefor, which can easily perform machining aimed at increasing hardness and reducing frictional resistance.

  In order to solve the above problems, the magnetically assisted machining method of the present invention provides a magnetic tool in a variable magnetic field, moves the magnetic tool by fluctuation of the magnetic field, and causes the magnetic tool to collide with a workpiece. In the magnetically assisted machining method, the magnetic tool is characterized in that it has at least magnetic anisotropy and the shape of the magnetic pole end is curved by machining or resin or metal coating.

  The magnetic tool of the present invention for solving the above-mentioned problems performs processing by arranging a magnetic tool in a variable magnetic field, accelerating the magnetic tool by the fluctuation of the magnetic field, and causing the magnetic tool to collide with a workpiece. A magnetic tool used in a magnetically assisted machining method, wherein the magnetic tool has at least magnetic anisotropy, and a shape of a magnetic pole end is a curved surface by machining or resin or metal coating.

  In the magnetic tool of the present invention, the magnetic tool has shape anisotropy.

  The magnetic tool of the present invention is characterized in that an abrasive is contained in the resin or metal.

  According to the magnetically assisted machining method of the present invention, the magnetic tool disposed in the varying magnetic field has at least magnetic anisotropy, and the shape of the magnetic pole tip is curved by machining or by resin or metal coating Therefore, as in the case of using a conventional pin-shaped magnetic tool, the sharp edge shape is transferred as it is onto the inner surface of the pipe, which is the workpiece, to prevent the formation of indentations in which the inner surface of the pipe is swollen into a V-groove shape. be able to. According to the magnetically assisted machining method of the present invention, since such a magnetic tool is used, a smooth inner surface shape can be obtained, and compression stress can be applied by selecting the material of the magnetic tool and the material of the resin or metal coating. It is possible to meet demands such as increased hardness by work hardening and reduced frictional resistance.

  According to the magnetic tool of the present invention, the magnetic tool has at least magnetic anisotropy, and the shape of the magnetic pole end is curved by processing or by resin or metal coating. For example, the inner surface of the pipe can be made smooth, and by selecting the material of the magnetic tool and the material of the resin or metal coating, it is possible to apply compressive stress, increase hardness by work hardening, reduce frictional resistance, etc. We can respond to requests.

  Further, according to the magnetic tool of the present invention, since the abrasive is contained in at least the resin or metal that covers the magnetic pole end, for example, the polishing state of the pipe inner surface can be adjusted by the action of the abrasive. Further, by changing the size and hardness of the abrasive, it is possible to adjust the compressive stress on the inner surface of the pipe that is the workpiece, adjust the hardness due to work hardening, and adjust the frictional resistance.

  Hereinafter, the magnetic assistance processing method of this invention and the magnetic tool used for this are demonstrated, referring drawings.

  The present invention is characterized by a magnetic tool used in a magnetically assisted machining method in which a magnetic tool is arranged in a varying magnetic field, the magnetic tool is moved by the fluctuation of the magnetic field, and machining is performed by causing the magnetic tool to collide with a workpiece. It is what has. Specifically, as a magnetic tool disposed in a variable magnetic field, a magnetic tool having at least magnetic anisotropy and having a magnetic pole tip shape that is a curved surface by processing or resin or metal coating is used. . Hereinafter, matters constituting the invention will be sequentially described in detail.

(Magnetic tool)
As a material for the magnetic tool according to the present invention, a soft magnetic metal material such as work-induced martensitic stainless steel or carbon steel is preferably used, but is not particularly limited thereto. Since magnetic tools made of these materials have magnetic anisotropy, in magnetic-assisted machining using a variable magnetic field, the magnetic tool moves due to the fluctuation of the magnetic field, and the magnetic tool collides with the workpiece to be machined. Will be processed.

  As a magnetic tool according to the present invention, as long as it is formed of the material as described above and has magnetic anisotropy, a metal material is processed, and a sintered material is processed. Also good. Further, the size, shape and the like are not particularly limited, but the shape preferably has at least shape anisotropy. A magnetic tool having shape anisotropy exhibits favorable motion behavior in a magnetically assisted machining method using a varying magnetic field. As an example of a magnetic tool having shape anisotropy, a pin-shaped tool as shown below is preferably used. In the case of a pin-shaped magnetic tool, a tool having a length of about 1 to 5 mm and a diameter of about 0.1 to 2 mm and a ratio of length to diameter (length / diameter) of about 2 to 25 is preferably used. .

  FIGS. 1A to 1D are schematic cross-sectional views showing examples of typical pin-shaped magnetic tools of the magnetic tool of the present invention. A magnetic tool 1A shown in FIG. 1 (A) has a pin-shaped end portion that is curved. The magnetic tool 1B shown in FIG. 1 (B) has a pin-shaped end portion that is a curved surface, and a coating material 2 made of resin or metal is coated on the curved surface. A magnetic tool 1C shown in FIG. 1C has a pin-shaped both end portions having rectangular end surfaces, and a covering material 2 made of resin or metal is further coated on the rectangular end surfaces. A magnetic tool 1D shown in FIG. 1 (D) has both ends of a pin shape as curved surfaces, and a coating material 2 made of resin or metal is coated on the curved surface, and the coating material 2 contains an abrasive. It is what. 1E is a conventional magnetic tool having a sharp edge with a wire cut.

  The end surfaces of the magnetic tools 1A, 1B, 1D according to the present invention in which both end portions are curved may be processed by machining such as polishing, or may be processed by heat treatment or the like. It may also be manufactured with a curved surface at the time of manufacture. The magnetic tools 1A, 1B, and 1D having such curved surfaces can reduce the surface roughness by making the indentation shape formed on the workpiece, which is a workpiece, smooth by a magnetically assisted machining method in a varying magnetic field. There is an effect that can be done. For example, by reducing the surface roughness of the pipe inner surface, there is an effect that the frictional resistance of the fluid flowing in the pipe can be adjusted.

  The curved end surfaces can also be achieved by a method of coating a resin on a rectangular end surface as in the magnetic tool 1C shown in FIG. The same effect as described above can be imparted to a magnetic tool which is coated with a coating material 2 made of resin and has curved ends. The resin material for forming the curved surface is preferably a hard resin that does not easily peel off even during magnetically assisted processing with a varying magnetic field. Examples of such resin materials include resin materials such as epoxy and cyanoacrylate.

  Moreover, like a magnetic tool 1B shown in FIG. 1B, a magnetic tool having curved surfaces at both ends can be covered with a covering material 2 made of resin or metal. With respect to the magnetic tool 1B obtained in this manner, both ends are coated with a resin or metal having characteristics different from those of the base metal part, so that processing derived from the characteristics of the resin or metal can be performed. For example, when a resin or metal that is softer than the base metal part is coated, the residual stress on the surface of the workpiece can be made smaller than that in which the resin or metal is not coated. Further, when the resin or metal harder than the base metal portion is coated, the residual stress on the surface of the workpiece can be increased as compared with the case where the resin or metal is not coated. Examples of the resin material include epoxy and cyanoacrylate, and examples of the metal material include copper and nickel.

  Further, as in the magnetic tool 1D shown in FIG. 1D, the abrasive 3 can be contained in the covering material 2 made of resin or metal covering both ends. The magnetic tool 1D coated with the coating material 2 containing the abrasive 3 can exhibit the effect of the abrasive 3. For example, (i) when the hard abrasive 3 is contained in the coating material 2 made of hard resin or metal, the surface of the workpiece can be effectively polished or the residual stress can be increased. In addition, (ii) when a soft abrasive 3 is contained in the hard resin or metal coating 2, the abrasive 3 acts as an elastic cushioning material, so that the surface of the workpiece is slightly It can be polished one by one or the residual stress on the workpiece surface can be reduced. Further, (iii) when a hard abrasive 3 is contained in the coating material 2 made of soft resin or metal, the coating material 2 acts as an elastic cushioning material, and the abrasive on the surface of the workpiece Since 3 slides slightly, it can grind | polish effectively and can grind | polish to a smooth surface. Further, (iv) when the soft abrasive 3 is contained in the soft resin or metal covering 2, the covering 2 and the abrasive 3 act as elastic cushioning materials. The surface of the workpiece can be polished little by little, and the residual stress on the surface of the workpiece can be reduced.

As such an abrasive 3, various particulate or powdery abrasives can be used. For example, Al ₂ O ₃ , SiC, ZrO ₂ , B ₄ C, diamond, cubic boron nitride, including, for example, A, WA, GC, SA, MA, C, MD, CBN in JIS display, Abrasives such as MgO, CeO ₂ or fumed silica can be mentioned. The size and shape of the abrasive 3 are not particularly limited, but are selected in consideration of the relationship with the thickness of the covering material 2 (resin or metal) to be coated. Such an abrasive 3 can be easily contained in the resin, and can also be easily contained in the metal by, for example, dispersion plating.

  FIG. 2 is a schematic view showing a magnetically assisted machining mode using the magnetic tool 1 of the present invention, (A) is a front view, and (B) is a plan view. In FIG. 2, a pipe 10 is used as a workpiece, a pin-shaped magnetic tool 1 is placed in the pipe 10, electromagnetic coils 20 and 20 are disposed in the vicinity of the pipe 10, and an alternating current is connected to the electromagnetic coils 20 and 20. A fluctuating magnetic field is generated by applying a current. In this way, as shown in FIGS. 2A and 2B, the magnetic tool 1 inside the pipe 10 collides with the inner surface of the pipe 10 to perform processing such as polishing.

  In the magnetic tool of the present invention described above, the shape of the magnetic pole end is curved by processing or by resin or metal coating. By arranging such a magnetic tool in a variable magnetic field, for example, the inner surface of the pipe is smooth. In addition to the shape, it is possible to meet demands such as applying compressive stress, increasing hardness by work hardening, and reducing frictional resistance by selecting the material of the magnetic tool and the material of the resin or metal coating.

  Further, according to the magnetic tool of the present invention, since the abrasive is contained in at least the resin or metal that covers the magnetic pole end, for example, the polishing state of the pipe inner surface can be adjusted by the action of the abrasive. Further, by changing the size and hardness of the abrasive, it is possible to adjust the compressive stress on the inner surface of the pipe that is the workpiece, adjust the hardness due to work hardening, and adjust the frictional resistance.

(Magnetic assisted processing)
Next, the magnetic assistance process of this invention performed using the magnetic tool of this invention as mentioned above is demonstrated.

  The magnetically assisted machining method of the present invention is characterized in that the magnetic tool according to the present invention as described above is used, and the rest is basically the same as the conventionally known magnetically assisted machining method. is there.

  That is, in the magnetically assisted machining method of the present invention, as conventionally known, a magnetic tool is arranged in a variable magnetic field, the magnetic tool is moved by the fluctuation of the magnetic field, and the magnetic tool is caused to collide with the workpiece. Processing.

  The variable magnetic field may be a magnetic field in which the N and S poles alternately change, such as an N / S alternating magnetic field and a rotating magnetic field. These magnetic fields are composed of, for example, permanent magnets, electromagnetic coils, or combinations thereof. When N / S alternating magnetic field by electromagnetic coil is adopted, current control (for example, energization of alternating current) is applied to the electromagnetic coil extending to the vicinity of the non-magnetic workpiece (workpiece) that becomes the machining field. A fluctuating magnetic field can be generated, and the magnetic force can be controlled by changing the energization frequency of the electromagnetic coil. In addition, when a rotating magnetic field using a permanent magnet is employed, a variable magnetic field can be generated, for example, by rotating a rotary table equipped with a permanent magnet, and the magnetic force is controlled by changing the rotational speed. can do.

  After placing a non-magnetic workpiece as a machining field in such a variable magnetic field generator, and storing the appropriate number of magnetic tools necessary for active three-dimensional behavior inside this workpiece , Give the workpiece a fluctuating magnetic field. A magnetic tool in a workpiece to which a varying magnetic field is applied is pulled by the variation of the magnetic field and causes three-dimensional irregular motion in the workpiece. Such irregular movement of the magnetic tool randomly collides with the surface of the workpiece, and can perform surface polishing and surface finishing of the workpiece, application of residual stress, surface hardening processing, or the like.

  As mentioned above, although the magnetic assistance processing method of this invention was demonstrated easily, about the detailed structure of the apparatus used, it can change suitably. For example, (a) the shape and material of the rotary table in the rotating magnetic field device, and its rotational drive mode, (b) the number of magnets installed on the rotary table to which the permanent magnet is attached and the magnetic pole array, (c) the magnet The variation control mode of the magnetic field, (d) the shape and material of the workpiece to be processed, (e) the shape and number of magnetic tools, and the like can be appropriately changed.

  The magnetically assisted machining method of the present invention can be expected to be applied to precision machining of various workpieces as an example of application. For example, processing such as precision polishing such as super clean pipes used in next-generation semiconductor and medical manufacturing processes, various ceramic pipes, and pipes with complex shapes such as T-shaped pipes and L-shaped pipes This is effective for processing products that require high precision and for products that require high-precision processing (polishing, etc.) in a minute space such as in a pipe. The magnetically assisted machining method of the present invention is not limited to such applications, but the bending fatigue strength due to the deburring of the details, inner surface, surface finish and edge of non-magnetic workpieces, or hardening of the surface layer, residual compression stress It can be widely applied to various uses for improving the quality.

  Hereinafter, the present invention will be described more specifically with reference to examples.

Example 1
FIG. 3 is a schematic front view (A) and plan view (B) showing an example of a magnetically assisted processing apparatus 30 using a varying magnetic field. When an alternating current (frequency: 7 Hz, voltage: 100 V) is supplied to the opposing electromagnetic coils 33, 33 from the AC stabilized power supply 36, the inside of the nonmagnetic pipe 10 installed between the iron cores 32, 32 provided in the opposing electromagnetic coils 33, 33 In addition, an N · S variable magnetic field is given. At this time, the interval between the opposed iron cores 32 and 32 is 3 mm, and the pipe 10 is arranged slightly below the positions of the iron cores 32 and 32 so that the distance between the iron cores 32 and 32 and the pipe 10 is 3 mm. . The processing time was 30 minutes. In FIG. 3, reference numeral 31 is a support jig for the pipe 10 as a workpiece, reference numeral 34 is a support jig for the electromagnetic coil, and reference numeral 35 is a machining stage.

  As the pipe 10 which is a workpiece, a SUS304 stainless steel circular tube (outer diameter 20 mm × inner diameter 18 mm × length 170 mm) was used. Further, as the pin-shaped magnetic tool, a 3.0 g equivalent number of pins made of SUS304 stainless steel and having an outer diameter of 1 mm and a length of 5 mm were used. The magnetic tool used here is a magnetic tool having the form shown in FIG. 1A, and both ends are machined into curved surfaces (curvature radius: 0.5 mm).

(Example 2)
As the pin-shaped magnetic tool, a magnetic tool (see magnetic tool 1B in FIG. 1B) in which a cyanoacrylate resin was applied to both ends of the magnetic tool of Example 1 to a thickness of about 20 μm was used. Furthermore, a SUS316L stainless steel circular pipe (outer diameter 20 mm × inner diameter 18 mm × length 170 mm) was used as the pipe 10 which is a workpiece. The other processes were performed in the same manner as in Example 1 using magnetically assisted processing.

(Example 3)
As the pin-shaped magnetic tool, one having both ends of the magnetic tool used in Example 1 which are not processed but rectangular ends is used, and a cyanoacrylate resin is formed to have a thickness of about 20 μm at both ends. A magnetic tool (see magnetic tool 1C in FIG. 1C) applied to was used. Furthermore, a SUS316L stainless steel circular pipe (outer diameter 20 mm × inner diameter 18 mm × length 170 mm) was used as the pipe 10 which is a workpiece. The other processes were performed in the same manner as in Example 1 using magnetically assisted processing.

Example 4
As a pin-shaped magnetic tool, cyanoacrylate resin is applied to both ends of the magnetic tool of Example 1 so as to have a thickness of about 20 μm, and alumina (WA # 400) having a particle size of 30 μm is included as an abrasive. A magnetic tool (see magnetic tool 1D in FIG. 1D) was used. Furthermore, a SUS316L stainless steel circular pipe (outer diameter 20 mm × inner diameter 18 mm × length 170 mm) was used as the pipe 10 which is a workpiece. The other processes were performed in the same manner as in Example 1 using magnetically assisted processing.

(Example 5)
As a pin-shaped magnetic tool, cyanoacrylate resin is applied to both ends of the magnetic tool of Example 1 so as to have a thickness of about 20 μm, and alumina (WA # 3000) having a particle size of 4 μm is included as an abrasive. A magnetic tool (see magnetic tool 1D in FIG. 1D) was used. Furthermore, a SUS316L stainless steel circular pipe (outer diameter 20 mm × inner diameter 18 mm × length 170 mm) was used as the pipe 10 which is a workpiece. The other processes were performed in the same manner as in Example 1 using magnetically assisted processing.

(Comparative Example 1)
Except for using a magnetic tool (see magnetic tool 1E in FIG. 1E) in which both ends of the magnetic tool used in Example 1 are not machined and are rectangular ends as a magnetic tool. Magnetic assist processing was performed in the same manner as in Example 1.

(result)
FIG. 4 shows the results of measuring the surface roughness (maximum height / Rz) of the inner surface of the pipe obtained by the magnetically assisted machining of Example 1 and Comparative Example 1. The surface roughness (maximum height / Rz) was measured by cutting a pipe and measuring the inner surface of the pipe with a stylus type surface roughness measuring device. The surface roughness (maximum height / Rz) was evaluated by the maximum height Rz measured according to JIS B 0601-2001 (based on ISO 4187-1997). As is apparent from the results of FIG. 4, the inner surface of the pipe obtained by the magnetically assisted processing of Example 1 has a small surface roughness (maximum height / Rz), and can be processed into a smooth surface. It was.

  FIG. 5 is a photomicrograph at this time. 5A is a photomicrograph of the inner surface of the pipe before processing, FIG. 5B is a photomicrograph of the inner surface of the pipe after magnetic-assisted processing of Example 1, and FIG. It is a microscope picture of the pipe inner surface after a magnetic assistance process. As can be seen from this result, the inner surface of the pipe obtained by the magnetically assisted processing of Example 1 was an inner surface having a uniform and fine indentation, but the inner surface of the pipe obtained by the magnetically assisted processing of Comparative Example 1 Had an inner surface with indentations in the shape of V-grooves.

  FIG. 6 shows the results of measuring the surface roughness (maximum height / Rz) of the inner surface of the pipes obtained by the magnetically assisted processing of Examples 2 to 5. The surface roughness (maximum height / Rz) was measured by the same method as that obtained in FIG. As is apparent from the results of FIG. 6, the pipe inner surface obtained by the magnetically assisted machining of Examples 2, 4 and 5 has a small surface roughness (maximum height / Rz) and is processed into a smooth surface. We were able to. In particular, the pipe inner surface obtained by the magnetically assisted processing of Example 5 containing fine alumina particles in the resin had a small surface roughness. On the other hand, the inner surface of the pipe obtained by the magnetically assisted processing of Example 3 showed a slightly high surface roughness. This is considered to be due to the influence of the rectangular shape at both ends.

  FIG. 7 is a photomicrograph of the inner surface of the pipe obtained by the magnetically assisted processing of Examples 2 to 5. As is clear from the results in FIG. 7, the pipe inner surface (see FIG. 7A) obtained by the magnetic-assisted machining of Example 2 was smooth, but was obtained by the magnetic-assisted machining of Example 3. It was confirmed that the inner surface of the pipe (see FIG. 7B) was slightly rough. This is considered to be due to the influence of the rectangular shape at both ends. In addition, the pipe inner surface (see FIG. 7C) obtained by the magnetic-assisted machining of Example 4 was confirmed to have a uniform indentation, but the pipe inner surface obtained by the magnetic-assisted machining of Example 5 (see FIG. 7C). 7 (D)), it was confirmed that finer impressions were uniformly formed. This is considered to depend on the particle size of the alumina particles in the resin.

  Furthermore, the residual stress of the pipe inner surface obtained by the magnetic assistance process of Examples 1-6 and Comparative Example 1 was measured. The residual stress was measured with an X-ray stress measuring device (manufactured by Rigaku Corporation, MSF2M) after cutting the processed pipe. The residual stresses on the inner surface of the pipes obtained by the magnetically assisted processing of Examples 1 to 6 and Comparative Example 1 were −353 ± 33 MPa, −273 ± 21 MPa, −320 ± 29 MPa, −250 ± 19 MPa, −187 ± in that order. They were 39 MPa and -379 ± 16 MPa. From this result, the pipe inner surface obtained by the magnetically assisted processing of Example 5 containing fine alumina particles in the resin has the smallest residual stress, and the one having the next smallest residual stress is the large alumina. It was the pipe inner surface obtained by the magnetic assistance process of Example 4 which contains particle | grains in resin. In addition, what has the highest residual stress was the pipe inner surface obtained by the magnetic assistance process of the comparative example 1.

  As is clear from the above results, it was confirmed that the surface shape, surface roughness, residual stress, etc. of the pipe inner surface can be controlled to a desired form by the shape of the magnetic tool, the covering material covering both ends, and the like. It was.

It is a schematic cross section showing an example of a typical pin-shaped magnetic tool of the magnetic tool of the present invention (note that (E) is a conventional example). It is a schematic diagram which shows the magnetic assistance process aspect using the magnetic tool of this invention. It is the front view (a) and top view (b) which show an example of the experimental apparatus using a variable magnetic field. It is the result of having measured the surface roughness (maximum height / Rz) of the inner surface of the pipe obtained by the magnetic assistance process of Example 1 and Comparative Example 1. FIG. It is a microscope picture of the inner surface of the pipe obtained by the magnetic assistance process of Example 1 and Comparative Example 1. It is the result of having measured the surface roughness (maximum height / Rz) of the inner surface of the pipe obtained by the magnetic assistance process of Examples 2-5. It is a microscope picture of the pipe inner surface obtained by the magnetic support process of Examples 2-5.

Explanation of symbols

1, 1A, 1B, 1C, 1D, 1E Magnetic tool 2 Coating material 3 Abrasive material 10 Pipe 20 Electromagnetic coil 30 Magnetically assisted processing device 31 Pipe support jig 32 Iron core 33 Electromagnetic coil 34 Electromagnetic coil support jig 35 Processing stage 36 AC stabilized power supply

Claims (4)

  In a magnetically assisted machining method in which a magnetic tool is arranged in a variable magnetic field, the magnetic tool is moved by movement of the magnetic field, and the magnetic tool is caused to collide with a workpiece, the magnetic tool is at least a magnetic A magnetically assisted machining method characterized by using a method having a magnetic property and having a magnetic pole tip having a curved surface by machining or resin or metal coating.   A magnetic tool used in a magnetically assisted machining method in which a magnetic tool is arranged in a variable magnetic field, the magnetic tool is moved by fluctuation of the magnetic field, and machining is performed by colliding the magnetic tool with a workpiece. A magnetic tool having magnetic anisotropy, wherein the shape of a magnetic pole tip is curved by processing or by resin or metal coating.   The magnetic tool according to claim 2, wherein the magnetic tool has shape anisotropy.   The magnetic tool according to claim 2, wherein an abrasive is contained in the resin or metal.

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