JP2950064B2 - Electrolytic dressing type grinding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic dressing type grinding apparatus for electrolyzing and dressing a work surface of a grindstone.

[0002]

2. Description of the Related Art In grinding difficult-to-cut materials such as ceramics, a resin diamond grindstone is generally used. However, this kind of diamond grindstone has a problem that since the holding power of the diamond grindstone is low, high rigidity machining is difficult and the life of the grindstone is extremely short. As a solution to these problems,
There is a cast iron bond whetstone that uses a metal bond that has a high holding strength for diamond abrasive grains.

[0003] This cast iron bond whetstone lacks the so-called spontaneous cutting action, which always causes a new sharp abrasive grain to protrude during the grinding, and causes clogging relatively early so that the grinding cannot be continued. Met. For this reason, in using this cast iron bond whetstone, a dressing operation for projecting diamond abrasive grains was indispensable.

As a method of projecting diamond abrasive grains, various electrolytic dressing methods have been proposed in which a metal bond made of cast iron is eluted by an electrolytic action to project abrasive grains. FIG. 6 shows a conventional electrolytic dressing method of this kind .
This will be described with reference to the grinding device shown in FIG.

FIG . 6 is a schematic structural view of a conventional electrolytic dressing type grinding apparatus. The grinding apparatus shown in FIG. 6 is disclosed in Japanese Patent Application Laid-Open No. 2-100872. In the figure, reference numeral 1 denotes a cup-shaped grindstone as a conductive tool (hereinafter simply referred to as a grindstone), 2 denotes an arbor for holding the grindstone 1, and the arbor 2 moves the grindstone 1 as shown by an arrow M in the figure. It has a structure to rotate.

Reference numeral 3 denotes an anode carbon brush slidably in contact with the outer peripheral surface of the grindstone 1, and reference numeral 4 denotes a cathode arranged in a pair with the anode carbon brush 3. The negative electrode 4 is disposed with a gap between the negative electrode 4 and a grinding work unit 5 located at the lower end of the grindstone 1. Reference numeral 6 denotes an electrolytic solution having a function as a grinding fluid, and 7 denotes a discharge nozzle for supplying the electrolytic solution 6 to the grindstone 1.
It is installed near.

In order to perform electrolytic dressing in the conventional grinding apparatus thus configured, a DC pulse charge is applied between the anode carbon brush 3 and the negative electrode 4,
Grinding wheel 1 via electrolytic solution 6 flowing between
Turn on electricity. In this way, the cast iron bond that forms the grinding work part 5 together with the diamond abrasive is eluted by electrolysis, and the diamond abrasive protrudes from the surface of the grinding work part 5. In the conventional grinding apparatus shown in FIG. 6 , the arbor 2 has an insulating structure to prevent electric charges from leaking to the grinding machine side.

[0008]

However, when the above-described electrolytic dressing method is used to perform the grinding as shown in FIG. 7 , there is a problem that the sizing workability is reduced. FIG. 7 is a sectional view showing a conventional electrolytic dressing type grinding apparatus for rotating a grindstone around a horizontal axis. In this figure, the same or equivalent members as those described in FIG. 6 are denoted by the same reference numerals, and detailed description is omitted. In FIG. 7 , reference numeral 8 denotes a work as a material to be ground, 9 denotes a work holder for holding the work 8, and the work holder 9 is formed of a stainless steel-based conductive material. Fixed.

In the grinding apparatus shown in FIG . 7 , the reason why the sizing workability is low is that the grinding work part 5 slightly moves toward the work shaft 10 through the work 8 and the conductive work holder 9 during the electrolytic dressing. Electrolyte solution 6 that may cause a short circuit or hang on workpiece shaft 10 during electrolytic dressing
This causes a slight leakage from the negative electrode 4 to the work shaft 10 through the negative electrode 4. When such leakage occurs, the electrolytic resistance value (electrolytic current value and electrolytic voltage value) involved in the electrolytic dressing action becomes unstable, and the low-dimensional workability decreases.

For this reason, for example, even when a high-precision grinding machine with an air bearing specification and a positioning accuracy of ± 0.1 μm is used, the limit of the sizing workability is about ± 2 μm as shown in FIG . That is, in the conventional electrolytic dressing type grinding apparatus, since precision in performing sizing processing is low, high-precision processing that requires sizing workability cannot be performed.
FIG. 8 is a graph showing sizing workability in a conventional electrolytic dressing type grinding apparatus.

[0011] Of the grinding wheels 1 dressed by the electrolytic dressing method described in the above-mentioned publications, etc., FIG.
The surface of the workpiece is mirror-finished (R
If the high-precision grinding processing to finish to MAX {200} or less is performed continuously, there is also a problem that the finishing accuracy of the ground surface is significantly reduced. FIG. 9 is an enlarged sectional view showing a grindstone used in a conventional grinding apparatus. In the figure, reference numeral 11 denotes a grindstone table formed in a disk shape, and 12 denotes a grindstone portion fixed to the grindstone table 11. The part 12 is formed in a cylindrical shape by diamond abrasive grains (super abrasive grains) and a cast iron bond. And
The end face of the grinding wheel portion 12 is the grinding work portion 5.

That is, when electrolytic dressing is performed using the grindstone 1 shown in FIG. 9 , the surface of the grindstone portion 12 is corroded by the electrolytic solution or the like as shown in FIG. Is generated on the surface of the grindstone portion 12.
Then, the corrosive substances constituting the corroded layer 13 fall off during the grinding process and enter between the grindstone portion 12 and the work (not shown), so that scratch marks are formed on the finished grinding surface of the work. The surface roughness of the ground surface on which the scratch marks are formed is as shown in FIG . As can be seen from FIG. 10, the unevenness of the finished surface of the work becomes extremely large.

The present invention has been made in order to solve such a problem, and even when machining by electrolytic dressing grinding, the sizing workability is ± 1 μm or less, and high-precision machining requiring sizing work is performed. It is an object of the present invention to make it possible to use electrolytic dressing grinding. Another object of the present invention is to provide an electrolytic dressing-type grinding apparatus that does not cause a reduction in surface roughness due to corrosive substances even when grinding is performed continuously to finish the surface of a work to a mirror surface. is there.

[0014]

According to a first aspect of the present invention, there is provided an electrolytic dressing type grinding apparatus in which a portion of an electrode located on a grinding wheel working surface side other than a surface facing the grinding wheel working surface is covered with a cover made of an insulating material. It is a thing.

In an electrolytic dressing type grinding apparatus according to a second aspect of the present invention, an electrode located on the grinding wheel working surface side and an electrolyte supply port through which an electrolyte flows out are arranged below the work.

The electrolytic dressing type grinding apparatus according to a third aspect of the present invention is a device in which a portion other than the working surface of the grinding wheel is covered with a thin film.

According to a fourth aspect of the present invention, in the electrolytic dressing type grinding apparatus, the grinding portion of the grindstone is formed by abrasive grains and a flexible bonding material that forms a film when corroded.

[0018]

According to the first and second aspects of the invention , the work supporting portion is insulated from the grindstone by the insulator.

According to the third aspect, it is difficult to form a corroded layer on the grindstone. According to the fourth aspect, when a corrosive substance generated on the grindstone enters between the grindstone and the work, the corrosive substance is crushed by the grindstone and the work.

[0020]

[Embodiment 1] FIG. 1 shows an electrolytic dressing type grinding apparatus according to the first invention.
Therefore, it will be described in detail. FIG. 1 is a cross-sectional view showing an electrolytic dressing type grinding apparatus according to the first invention. In FIG. 1 , the same or equivalent members as those described in FIG. 6 and FIG. Omitted.

In FIG . 1 , reference numeral 41 denotes an insulating cover that covers the cathode 4. The insulating cover 41 is formed of an insulating material, and has a structure that covers the entire surface of the cathode 4 other than the surface facing the grinding work section 5.

When the cathode 4 is covered with the insulating cover 41 as described above, the current is suppressed from leaking from the cathode 4 to the work supporting portion including the work holder 9 and the work shaft 10 via the electrolytic solution 6, and the electric charge is ground. It can flow only between the work unit 5. Therefore, power consumption other than the electrolytic dressing action can be prevented, and the electrolytic resistance value becomes stable.

Embodiment 2 FIG. The electrolytic dressing type grinding apparatus according to the second invention will be described with reference to FIG . FIG. 2 is a sectional view showing an electrolytic dressing type grinding apparatus according to the second invention .
The same or equivalent members as those described with reference to FIG. 7 are denoted by the same reference numerals, and detailed description is omitted.

The arrangement of the cathode 4 and the discharge nozzle 7 in the grinding apparatus shown in FIG . 2 is changed as compared with the conventional apparatus.
The cathode 4 and the discharge nozzle 7 are arranged below the work 8, the work holder 9 and the work shaft 10. The discharge nozzle 7 is directed substantially upward so that the electrolyte supply port 51 from which the electrolyte 6 is discharged is directed to the grinding work unit 5 and the cathode 4.

With this configuration, even if the electrolytic solution 6 discharged from the discharge nozzle 7 drops from the cathode 4 or the grindstone 1, the electrolytic solution 6 does not hang on the work supporting portion including the work holder 9 and the work shaft 10. Therefore, no electric leakage occurs through the electrolytic solution 6 applied to the work supporting portion, so that power can be prevented from being consumed in addition to the electrolytic dressing action, and the electrolytic resistance value is stabilized.

Embodiment 3 FIG. The electrolytic dressing type grinding apparatus according to the third invention will be described with reference to FIG . FIG. 3 is a cross-sectional view of an electrolytic dressing grindstone used in the electrolytic dressing type grinding apparatus according to the third invention . In FIG. 3 , the same or similar members as those described in FIG. 9 and FIG. The detailed description is omitted.

In FIG . 3 , reference numeral 61 denotes an electrolytic dressing grindstone, and the electrolytic dressing type grinding apparatus according to the third invention is constructed by mounting the grindstone 61 thereon. The grindstone 61 includes a grindstone base 11 supported by an arbor (not shown),
A cylindrical grinding wheel portion 12 fixed to the grinding wheel base 11
And a corrosion prevention film 62 attached to the inner and outer peripheral surfaces of the grindstone portion 12.

The grinding wheel 12 is made of diamond or CBN.
And the like, and a binder such as a cast iron bond, and one end in the axial direction is fixed to the grindstone stand 11. The other end in the axial direction is a grinding work section 5.

The corrosion prevention film 62 is formed by, for example, applying electrolytic plating or painting to the grindstone portion 12 and applying a thin film over the entire inner and outer peripheral surfaces of the grindstone portion 12. .

When the portion other than the grinding work portion 5 of the grindstone portion 12 is covered with the corrosion prevention film 62, the grindstone 61 is left for a long time at the time of setting up the grinding process, or electrolytic dressing is performed during the grinding process. Even if it does, oxides and the like can be suppressed from being generated on the inner and outer peripheral surfaces of the grindstone portion 12.

Therefore, since no oxide is generated in the grinding wheel portion 12, it is possible to prevent powder such as an oxide (corrosive substance) from entering between the grinding work portion 5 and a work (not shown). For this reason, even when the workpiece is continuously ground, high-precision mirror finishing can be performed without generating scratch marks on the processed surface of the workpiece.

When the grindstone 61 was used, the surface roughness of the processed surface of the work was as shown in FIG . FIG. 4 is a graph showing the surface roughness of the work after being ground by the grindstone 61 of the present embodiment . As is clear from the measurement results shown in FIG. 4, the work surface of the work has no scratch marks and is extremely smooth. It can be seen that the ground surface can be obtained stably.

In this embodiment, an example is shown in which the corrosion prevention film 62 is formed by electrolytic plating or painting. However, the film formation method is not limited to this, and can be changed as appropriate.

Embodiment 4 FIG. The electrolytic dressing type grinding apparatus according to the fourth invention will be described with reference to FIG . FIG. 5 is a cross-sectional view of an electrolytic dressing grindstone used in the electrolytic dressing type grinding apparatus according to the fourth invention . In FIG. 5 , the same reference numerals are used for the same or equivalent members as those described in FIG. 9 and FIG. The detailed description is omitted.

In FIG . 5 , reference numeral 81 denotes a grinding wheel for electrolytic dressing, and an electrolytic dressing type grinding apparatus according to a fourth aspect of the present invention is equipped with the grinding wheel 81. The grindstone 81 includes a grindstone base 11 supported by an arbor (not shown),
A grindstone portion 82 as a cylindrical grinding portion fixed to the grindstone table 11 is formed.

The whetstone portion 82 is made of diamond or CBN.
And the like, and a binder made of a material having a soft hardness of a corrosive substance that is precipitated when corroded, is formed in a cylindrical shape, and one end in the axial direction is fixed to the grindstone table 11. . The other end in the axial direction is a grinding work section 5. A mixture of a metal and a resin (resin) is employed as a binder made of a material in which the hardness of the corroded substance precipitated when corroded is flexible. That is, instead of the conventional grindstone portion 12 made of a super-abrasive such as diamond or CBN and a binder such as a cast iron bond, diamond or CBN is used.
And the like, and a binder 82 formed by a super-abrasive such as a super-abrasive and a binder made of a material having a soft hardness of a corrosive substance precipitated when corroded. I have.

When electrolytic dressing grinding is performed using the grinding wheel 81 configured as described above, a corrosive layer indicated by reference numeral 83 in FIG. 5 is formed on the inner and outer peripheral surfaces of the grinding wheel portion 82. The precipitated substance constituting the corroded material layer 83 is iron hydroxide [Fe
(OH) ₂ and 2Fe (OH) ₃ ], and the hardness is soft. Therefore, even if the powder of the corrosive material layer 83 enters between the grinding work part 5 and the work (not shown), Is crushed by the grindstone portion 82 and the work. Therefore, even when the workpiece is continuously ground, high-precision mirror finishing can be performed without causing scratch marks on the processed surface of the workpiece.

In each of the above-described embodiments, an example in which surface grinding is performed using a cup-shaped grindstone having a cup-like shape has been described. is not. That is, a flat grindstone or the like may be used, and a grinding method such as centerless grinding may be used.

In addition, the abrasive grains of the grindstone are not limited to superabrasive grains such as diamond and CBN as shown in each embodiment. That is, silicon carbide or the like can be used as the abrasive grains. In addition, as described in each embodiment, the grindstone portion can be formed by interposing a pore portion in addition to being formed only by the abrasive grains and the binder.

[0040]

Electrolytic dressing type grinding apparatus according to the first invention described above, according to the present invention is positioned in the grinding wheel work industry surface
Clean the part of the electrode other than the surface facing the grindstone working surface.
Covered with a cover made of a rim material,
The electrolytic dressing type grinding apparatus according to the present invention is such that the electrode located on the grindstone working surface side and the electrolytic solution supply port from which the electrolytic solution flows out are arranged below the work. Is insulated from the grindstone side by the insulator.

Therefore, when the grinding is performed by the electrolytic dressing type grinding apparatus according to the first and second aspects of the present invention , the electric charge does not leak to the work supporting portion side and the electrolytic resistance value related to the electrolytic dressing action is stabilized. be able to. For this reason, there is an effect that electrolytic dressing grinding can be used in performing high-precision machining requiring fixed-size machining.

Electrolytic dressing type grinding according to the third invention
The equipment covers the whetstone other than the working surface with a thin film.
Therefore, according to the present invention, a corrosion layer is formed on the grindstone.
It is difficult to generate.

In the electrolytic dressing type grinding apparatus according to the fourth aspect of the present invention , the grinding portion of the grinding wheel is formed by the abrasive grains and the film formed when corroded by a soft bonding material. When the corroded material enters between the grindstone and the work, the corroded material is crushed by the grindstone and the work.

Therefore, according to the electrolytic dressing type grinding apparatus according to the third and fourth aspects of the present invention , even when grinding the surface of the work to a mirror finish, the surface roughness may be reduced by corrosive substances. Absent. Moreover, it can be used stably and continuously.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an electrolytic dressing type grinding apparatus according to a first invention.

FIG. 2 is an electrolytic dressing type grinding machine according to a second invention .
FIG.

FIG. 3 is an electrolytic dressing type grinding machine according to a third invention .
FIG. 2 is a cross-sectional view of an electrolytic dressing whetstone used for installation.

FIG. 4 is an electrolytic dressing type grinding machine according to a third invention .
Graph showing the surface roughness of the workpiece after grinding
It is.

FIG. 5 is an electrolytic dressing type grinding apparatus according to a fourth invention .
FIG. 3 is a cross-sectional view of an electrolytic dressing whetstone used for the present invention.

FIG. 6 is a schematic configuration of a conventional electrolytic dressing type grinding apparatus.
FIG.

FIG. 7 shows a conventional electrolytic cell that rotates a grindstone around a horizontal axis .
It is sectional drawing which shows a lessing type grinding apparatus.

FIG. 8: Sizing with a conventional electrolytic dressing type grinding machine
It is a graph which shows workability.

FIG. 9 is an enlarged view of a grinding wheel used in a conventional grinding device .
FIG.

FIG. 10 is an enlarged view of a grinding wheel used in a conventional grinding device .
FIG. 3 is a cross-sectional view showing a state in which a corrosive substance is generated.

FIG. 11 shows a work after grinding by a conventional grinding device .
3 is a graph showing the surface roughness of the work.

[Description of Signs] 1 ... Whetstone, 3 ... Anode carbon brush, 4 ... Cathode, 5 ...
Cutting part, 8 ... Work, 41 ... Insulating cover, 51 ... Electrolysis
Liquid supply port, 62: anti-corrosion film, 82: whetstone part, 83: rotten
Food layer.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-95574 (JP, A) JP-A-4-315573 (JP, A) JP-A-51-45398 (JP, A) JP-A-6-45574 143130 (JP, A) JP-A-6-114732 (JP, A) JP-A-6-55441 (JP, A) JP-A-6-775 (JP, A) (58) Fields investigated (Int. ⁶ , DB name) B24B 53/00

Claims (4)

(57) [Claims] 1. An electric machine opposing a work surface of a grindstone with a gap.
Electrodes are applied to this grindstone and the work surface is
Electrolytic dressing grinding dressing by decomposition
In the device, facing the grinding wheel working surface in the electrode
Other parts than the surface were covered with a cover made of insulating material
An electrolytic dressing type grinding apparatus characterized by the above-mentioned. 2. An electric machine opposing a work surface of a whetstone with a gap.
Electrodes are applied to this grindstone and the work surface is
Electrolytic dressing grinding dressing by decomposition
In the apparatus, the electrode and the electrolyte flowing out are discharged.
The liquid supply port is located below the workpiece.
Electrolytic dressing type grinding machine. 3. An electric machine opposing a work surface of a grindstone with a gap.
Electrodes are applied to this grindstone and the work surface is
Electrolytic dressing grinding dressing by decomposition
In the apparatus, a portion other than the working surface of the whetstone is formed by a thin film.
Dressing type grinding characterized by coating with
apparatus. 4. An electric machine opposing a work surface of a whetstone with a gap.
Electrodes are applied to this grindstone and the work surface is
Electrolytic dressing grinding dressing by decomposition
In the apparatus, the grinding portion of the whetstone, the abrasive, and corroded
Is formed by the flexible binder
And an electrolytic dressing type grinding device.