JP3947824B2 - Processing method and apparatus using magnetic powder - Google Patents

Description

  The present invention relates to a precision processing method such as polishing, grinding, and cutting, and more particularly to a precision processing method and apparatus using magnetic powder.

  For precision processing such as polishing, grinding, cutting, etc., select a processing tool such as a grinding wheel, cutting edge, drill, etc. according to the purpose, and work the workpiece while vibrating, generating ultrasonic waves, linearly or rotating it. Slide against the object.

At this time, when a relatively small portion is precisely machined, it is common to place abrasive powder on the sliding surface of the contact portion between the machining end and the workpiece.
As the abrasive powder, a so-called super hard powder mainly composed of alumina or tungsten carbide is used.

  Abrasive powder is scattered by processing movement, and the degree of scattering can be reduced by supplying the abrasive powder to the vicinity of the contact point together with the gel or paste binder, but it still slides between the abrasive powder and the binder. In order to continuously exist on the surface, it is necessary to continuously supply abrasive powder and binder, or binder containing abrasive powder.

  Therefore, not only the consumption of the abrasive powder is increased, but there are problems such as presence / absence of the abrasive powder at the contact location, variation in processing quality due to some, instability, and non-uniformity.

In addition, when the ability of the binder to prevent scattering is increased, secondary bonding of the abrasive grains proceeds, and the size of the powder becomes excessive, resulting in a problem that the processing performance as the abrasive grains decreases.
Moreover, there is a concern about the influence of the scattered abrasive powder on the human body and the environment.

Patent Document 1 discloses a technique for collecting scattered abrasive powder by providing and sucking a cover that covers a contact location in relation to cleaning of a grindstone.
However, even if the abrasive powder is collected in this way, continuous replenishment of the abrasive powder and the binder is necessary, and the above problem cannot be solved.
Japanese Patent Laid-Open No. 06-091531

  Accordingly, the present invention has been made to solve the above problems in precision processing methods such as polishing, grinding, cutting, etc. using abrasive powder, particularly when precision processing is performed on relatively small parts, It is an object of the present invention to provide a processing method using magnetic powder and an apparatus thereof that eliminate the need for continuous replenishment of a binder and abrasive powder.

  In addition, the present invention eliminates the need for a binder, suppresses secondary bonding of the abrasive powder, prevents deterioration of the processing performance of the abrasive powder, and suppresses the influence on the human body and the environment due to the scattering of the abrasive powder. An object of the present invention is to provide a processing method and apparatus using magnetic powder.

In order to achieve the above object, a processing method using magnetic powder according to the present invention is a processing method in which abrasive powder is interposed in a gap between a processing end on which a processing tool slides and a processing portion of a workpiece. The granular powder is a magnetic powder having magnetism, and a magnetized superconducting bulk magnet is used to apply a magnetic field concentrated on a portion including the gap .

Furthermore, the superconducting bulk magnet is installed substantially parallel to the uppermost part inside the vacuum vessel, and the processed part is installed in the central part immediately above the superconducting bulk magnet .

Preferably, as described in claim 2, the magnetic powder is tungsten carbide (WC) containing cobalt (Co) .

According to a third aspect of the present invention, the magnetized cemented carbide powder is a discarded and collected cemented carbide powder or recycled from a cemented carbide processing end .

In order to achieve the above object, a processing apparatus using magnetic powder according to claim 4 of the present invention interposes abrasive powder in a gap between a processing tool having a sliding processing end and a processing portion of a workpiece. In the processing apparatus, the abrasive powder is magnetic powder, and a magnetized superconducting bulk magnet is used to apply a magnetic field concentrated on a portion including the gap .

Furthermore, the superconducting bulk magnet is installed substantially parallel to the uppermost part inside the vacuum vessel, the processing part is installed in the central part immediately above the superconducting bulk magnet, and the workpiece is magnetized. It is mounted in the center part of the direct upper part of .

According to a fifth aspect of the present invention, the magnetic powder is tungsten carbide (WC) containing cobalt (Co).

According to a sixth aspect of the present invention, the magnetic powder is recycled from a discarded super hard powder or a super hard processing end.

  In precision processing such as polishing, grinding, and cutting, especially when precision processing is performed on a relatively small part, magnetic powder as abrasive powder that is interposed in the gap between the processing end where the processing tool slides and the processing part of the workpiece is used. Providing a processing method and apparatus using magnetic powder that prevents scattering and keeps the abrasive powder between the sliding surfaces, eliminating the need for a binder and eliminating the need for continuous supply of abrasive powder. can do.

  In particular, when the abrasive grain powder to which the present invention is applied is tungsten carbide (WC) containing cobalt (Co), the amount of cemented carbide such as tungsten carbide (WC), which is discarded and collected in the conventional processing process, is usually small. Therefore, it can be easily recycled as it is or with minimal preparation.

  Embodiments according to the present invention will be specifically described below with reference to the drawings.

  Referring to FIG. 1, in general, in a precision machining method, a workpiece 10 is placed on a support base 41, a paste 20 containing abrasive powder 25 is applied to a machining portion of the workpiece 10, and a machining tool 31 is machined. The end 30 is slid against the processed part of the workpiece 10.

  At that time, in the processing method using the magnetic powder according to the present invention, the magnetic powder is used as the abrasive powder 25, and the magnet 40 is incorporated immediately below the work surface of the support base 41.

  As the material of the abrasive powder, tungsten carbide (WC) containing cobalt (Co) having super hardness and ferromagnetism is used.

  Tungsten carbide containing cobalt may be obtained by recycling used cemented carbide powder or cemented carbide material that has been conventionally discarded.

In the present embodiment, a permanent magnet, an electromagnet using an electromagnetic solenoid, or a magnet using a superconducting coil is used as the magnet 40, so that the generated magnetic force lines 50 are generated by the magnet 40 that is a processing part of the workpiece 10. It is concentrated directly above.
That is, the magnetic flux density is the highest directly above the magnet 40.

Referring to FIG. 2A, a magnetic flux density distribution in the case of a permanent magnet is shown.
When the disk-shaped magnet is horizontally (x, y direction), the disk surfaces on both sides become N and S poles, and the magnetic flux extends in the z direction through the disk surface. And (b) in FIG. 2 (A) and the next (B) in the vertical direction of the figure, and the value obtained by measuring the magnetic flux density B in the z direction in units of Tesla (T) is represented by Bz (T). Shown for points.

The magnetic flux density takes a substantially uniform value, 0.3 T (Tesla), from the central portion to the entire peripheral portion immediately above the magnet, and rapidly decreases at the peripheral portion of the magnet.
Correspondingly, the lines of magnetic force 50 in FIG. 1 are densely present at equal intervals immediately above the magnet 40.

  A similar magnetic flux density distribution is shown in the case of an electromagnet using an electromagnetic solenoid or a magnet using a superconducting coil. The maximum magnetic flux density directly above the magnet is 2 tesla and 3 tesla, respectively.

  In general, the magnetic powder is attracted not only to the magnetic flux density but also to a location where the product of the magnetic flux density and the magnetic flux density gradient is large.

  That is, in the case of the present embodiment, the magnetic powder 25 gathers at the periphery of the magnet and does not scatter to the outside any longer, so that it is not necessary to continuously replenish the magnetic powder as abrasive powder or the replenishment frequency can be reduced. effective.

  Here, with reference to FIG. 2B, an example of distribution of magnetic flux density in the case of a magnetized superconducting bulk magnet is shown. The magnetic flux density has a steep peak of 1.7 Tesla in the central part immediately above the magnet, and decreases rapidly toward the peripheral part. The peak value of 1.7 Tesla in this example is for liquid nitrogen cooling (77 ° K), and in the case of helium cooling (35 ° K), a peak value of 3 Tesla or more is obtained.

  Therefore, in the case of a superconducting bulk magnet, the product of the magnetic flux density and the magnetic flux density gradient shows a steep peak on the center of the magnet, more precisely on the circumference very close to the center. Even if it is an integral magnet, the desired attractive force for the magnetic powder can be obtained.

Referring to FIG. 3, in the second embodiment of the present invention, the above-mentioned characteristics of the superconducting bulk magnet are utilized.
That is, the superconducting bulk magnet 40 is accommodated in a vacuum vessel 42, the vacuum vessel 42 is extended and connected to a vacuum port 44 and connected to a refrigerator 46, and a helium pipe 48 is connected to the refrigerator 46. The

  The vacuum port 44 and the helium pipe 48 are connected to a vacuum pump and a compressor (not shown), respectively, and the superconducting bulk magnet 40 is cooled to a predetermined temperature at a predetermined degree of vacuum, as shown in FIG. A magnetic field having a shape (however, because of refrigerator cooling, the peak value of the magnetic flux density B exceeds 3 Tesla instead of 1.7 Tesla).

  Magnetic field lines 50 of the magnetic field generated by the superconducting bulk magnet 40 are denser in the vicinity of the center just above the magnet 40 corresponding to the above magnetic flux density distribution, and become rapidly sparse as they leave the center.

As a result, the magnetic powder 25, which is abrasive powder, concentrates in the very vicinity of the center of the magnet 40, and does not scatter even if the processing operation proceeds there.
In addition, a present Example is related to a grinding | polishing process, the vibration head 32 which is a process end of the ultrasonic vibration generator 33 which is a processing tool is applied to the process part of the workpiece 10, and the magnetic powder 25 intervened. Slide in the state.

  Referring to FIG. 4, the third embodiment according to the present invention relates to a grinding process when a magnetized superconducting bulk magnet is used, and a rotation which is a processing end by a rotating mechanism 35 which is a processing tool. The grindstone 34 is rotated and applied to the processed portion of the workpiece 10 and is slid with the magnetic powder 25 interposed.

  Referring to FIG. 5, a fourth embodiment according to the present invention relates to cutting when a magnetized superconducting bulk magnet is used, and a drill which is a processing end by a rotating mechanism 37 which is a processing tool. While rotating the blade 36, the blade 36 is applied to the processed portion of the workpiece 10 and is slid with the magnetic powder 25 interposed therebetween.

ADVANTAGE OF THE INVENTION According to this invention, the precision processing method and processing apparatus which perform grinding | polishing, grinding, cutting, etc. under the intervention of a cemented carbide powder which can be operated continuously without additional replenishment of the cemented carbide powder are obtained. In addition, magnetic powder that is super hard powder, particularly tungsten carbide containing cobalt, can be obtained by recycling used super hard powder or super hard material that has been conventionally discarded.
Therefore, it can be expected to be utilized in machine tools in all fields of industry, particularly precision machine tools.

It is a figure which shows the processing apparatus using the magnetic powder by this invention, and explains a processing method. (A) is a figure which shows the example of the magnetic flux density distribution of a permanent magnet, (B) is a figure which shows the example of the magnetic flux density distribution of the superconducting bulk magnet magnetized. It is a figure which shows the processing apparatus (ultrasonic polishing apparatus) using magnetic powder at the time of using the magnetized superconducting bulk magnet by this invention, and explains a processing method. It is a figure which shows the processing apparatus (grinding apparatus) using a magnetic powder at the time of using the superconducting bulk magnet magnetized by this invention, and is a figure explaining a processing method. It is a figure which shows the processing apparatus (cutting apparatus) using a magnetic powder at the time of using the magnetized superconducting bulk magnet by this invention, and explains a processing method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Workpiece 20 Paste 25 Abrasive powder, magnetic powder 30 Processing end 31 Processing tool 32 Vibration head 33 Ultrasonic vibration generator 34 Rotary grindstone 35 Rotating mechanism 36 Drill blade 37 Rotating mechanism 40 Magnet, magnetized superconducting bulk Magnet 41 Support base 42 Vacuum vessel 44 Vacuum port 46 Refrigerator 48 Helium piping 50 Magnetic field lines

Claims (6)

In a processing method in which abrasive powder is interposed in a gap between a processing end on which a processing tool slides and a processing portion of a workpiece, the abrasive powder is magnetic powder having magnetic properties and is concentrated on a portion including the gap. In order to apply a magnetic field , a magnetized superconducting bulk magnet is used, and the superconducting bulk magnet is installed substantially parallel to the uppermost part inside the vacuum vessel, and the processing part is a central part immediately above the superconducting bulk magnet. A processing method using magnetic powder, characterized by being installed in The processing method using magnetic powder according to claim 1, wherein the magnetic powder is tungsten carbide (WC) containing cobalt (Co). The processing method using magnetic powder according to claim 2, wherein the magnetic powder is a discarded and collected super hard powder or a recycle manufactured from a super hard processing end. In a processing apparatus in which abrasive powder is interposed in a gap between a processing tool having a sliding processing end and a processing portion of a workpiece, the abrasive powder is magnetic powder with magnetism and concentrated on a portion including the gap In order to apply a magnetic field to be magnetized, a magnetized superconducting bulk magnet is used, the superconducting bulk magnet is installed substantially parallel to the uppermost part inside the vacuum vessel, and the processing unit is located at the center immediately above the superconducting bulk magnet. installed in parts, the machining apparatus workpiece with magnetic powder, characterized in that mounted on the central portion of the straight upper portion of the magnetized superconducting bulk magnet. The processing apparatus using magnetic powder according to claim 4 , wherein the magnetic powder is tungsten carbide (WC) containing cobalt (Co) . The processing apparatus using magnetic powder according to claim 5 , wherein the magnetic powder is a discarded super hard powder or a recycle manufactured from a super hard processing end .

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