JPH05138533A - Polishing device and method - Google Patents

Abstract

PURPOSE:To carry out a stable grinding work with high accuracy while electrolytic in-process dressing of a grinding tool being achieved in a uniform manner. CONSTITUTION:A cathode 3 which is of approximate shape of a surface to be worked 2 of a conductive grinding tool 1 is held by keeping a micro clearance between the cathode and the surface to be worked 2. A weak electrolytic coolant 5 is supplied form a nozzle 4 to a space between the cathode 3 and the surface to be worked 2. A plurality of grooves 6 are formed underside of the cathode 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for grinding an optical element by electrolytic in-process dressing grinding method.

[0002]

2. Description of the Related Art Conventionally, there is an electrolytic in-process dressing grinding method as a grinding apparatus for performing spherical grinding on an optical element by a subordinate grinding method. An example of applying this electrolytic in-process dressing method is, for example, Japanese Patent Laid-Open No. 3-6.
There is an invention described in 0974.

FIG. 7 showing the construction of the main part of the apparatus according to the above invention.
Will be explained. The workpiece 71 is rotatably held with an axis passing through the centers of curvature of the two workpiece surfaces of the workpiece 71 as a rotation axis, and swings while facing the two workpiece surfaces of the workpiece 71. Two conductive grinding tools 72a, 72b rotatably arranged and two conductive grinding tools 72a arranged at a predetermined distance from the processed surface, and a negative electrode 73a while maintaining a predetermined distance 1 from the processed surface of the conductive grinding tool 72b, 73b is provided. This anionic 73a, 73b and conductive grinding tool 7
2a and 72b and weak electric coolants 74a and 74b
Of the conductive grinding tools 72a, 72b as an anode while performing electrolytic dressing.
By using a and 72b, two workpiece surfaces of the workpiece 71 are simultaneously ground.

[0004]

In order to perform grinding by the electrolytic in-process dressing grinding method, a negative electrode having an area of 1/4 to 1/6 of the area of the processed surface of the conductive grinding tool is provided. I have to do it. Also, in order to perform stable machining, sufficient weak electric coolant should always be supplied between the entire surface of the opposite surface of the negative electrode facing the machined surface of the conductive grinding tool and the machined surface of the conductive grinding tool. Is essential.

In the conventional example, the conductive grinding tool 72 is used.
8 is a top view of the conductive grinding tool 72 showing the positional relationship between the negative electrode 73 and the negative electrode 73. When spherical grinding is performed on the workpiece 71 by the subordinate grinding method, the conductive grinding tool 72 needs to have a large surface area for covering the entire surface of the workpiece 71, and the cathode electrode is inevitably necessary. The area of 73 also becomes large. Therefore, in the conventional example, the negative electrode 7
Since the area of 3 is large, the negative electrode 73 and the conductive grinding tool 72
In addition to being unable to supply a sufficient amount of weakly electrically conductive coolant 74, stable electrolytic dressing cannot be performed on the conductive grinding tool 72, and uneven wear of the conductive grinding tool 72 is likely to occur. Further, in order to perform high-speed processing, the rotation speed of the conductive grinding tool 72 is increased, but in that case, the centrifugal force is also increased, and there is a problem that the weakly-electrically charged coolant 74 cannot be stably supplied.

Therefore, the present invention was developed in view of the above-mentioned problems in the prior art. When the electrolytic in-process dressing grinding method is applied, a sufficient weak electric current is provided between the negative electrode and the conductive grinding tool. An object of the present invention is to provide a grinding apparatus and method for supplying a stable coolant to perform stable and uniform electrolytic dressing.

[0007]

SUMMARY OF THE INVENTION According to the present invention, an anode is applied to a conductive grinding tool which is rotatably and rotatably arranged so as to face a surface of a workpiece to be rotatably held.
In addition, a cathode is applied to the electrode arranged at a predetermined distance from the processed surface of the conductive grinding tool, and a workpiece is ground while supplying a weak electric coolant between the conductive grinding tool and the electrode. In the electrolytic in-process dressing grinding method, the grinding is performed while supplying the weakly-electrolyte coolant to the groove formed on the surface of the electrode facing the conductive grinding tool.

Further, a work holding portion for rotatably holding a workpiece, a conductive grinding tool which is arranged so as to oscillate and rotate so as to face the surface of the workpiece, and the conductive grinding. An electrode having a groove formed on the surface facing the machined surface of the tool and arranged at a predetermined distance, a power source for applying an anode to the conductive grinding tool and a cathode to the electrode, and the conductive grinding tool. It is composed of a supply unit for supplying a weakly electric coolant between the electrodes.

1 and 2 are conceptual diagrams of the present invention.
2 is a plan view, and FIG. 2 is a sectional view taken along the line AA ′ of FIG. Reference numeral 1 denotes a conductive grinding tool, and a negative electrode 3 having a shape similar to that of the processed surface 2 of the conductive grinding tool 1 is held at the conductive surface of the conductive grinding tool 1 with a minute gap 1 therebetween. In addition, the weakly electric coolant 5 is supplied from the nozzle 4 between the negative electrode 3 and the processed surface 2. Further, as shown in FIG. 2, a plurality of grooves 6 are formed on the lower surface of the negative electrode 3.

With the above structure, the weakly electrically conductive coolant 5 ejected from the nozzle 4 during processing rotates about the rotation axis in the direction of arrow B. Then, the conductive grinding tool 1 is rotated to be guided between the processing surface 2 and the negative electrode 3, but is guided to the groove 6 provided in the negative electrode 3 and evenly spreads over the entire surface of the negative electrode 3. ..

[0011]

Embodiment 1 FIGS. 3 and 4 show an apparatus used in this embodiment, FIG. 3 is a side sectional view, and FIG. 4 is a schematic plan view. The grinding apparatus shown in the present embodiment is an embodiment in which a ball center grinder that swings around the ball center of the processed surface of the conductive grinding tool is used.

The member 11 to be processed is fixed to the holder 12 with an adhesive, and is held rotatably about the rotation axis Y by the hammer 13. Further, the processed surface 14 of the processed member 11 has a processed surface 15 having the same curvature as the processed surface 14.
An electroconductive grinding tool 16 including is arranged so as to oppose so as to swing around a ball center O and be rotatable about a rotation axis X. Further, a fan-shaped negative electrode 18 is provided in which a plurality of grooves 17 are formed on the surface facing the processing surface 15 while maintaining a minute gap (0.1 to 0.2 mm) facing the processing surface 15 of the conductive grinding tool 16. Are arranged.

Then, the conductive grinding tool 16 is electrically connected to the anode of the electrolytic dressing power source 21 through a power feeding brush 20 which is disposed in sliding contact with the rotary shaft 19, and
The negative electrode 18 is electrically connected to the cathode of the electrolytic dressing power source 21. Further, between the conductive grinding tool 16 and the negative electrode 18, and between the conductive grinding tool 16 and the work surface 14 of the work member 11,
Nozzles 23 and 24 for supplying the weak electric coolant 22 are provided respectively.

In order that the supplied weak electric coolant 22 is not scattered by the centrifugal force generated by the rotation of the conductive grinding tool 16, the discharge direction of the weak electric coolant 22 is perpendicular to the side surface of the negative electrode 18 and is made conductive. It is arranged in the same direction as the rotation direction of the grinding tool 16. Further, the pattern shape of the groove 17 of the negative electrode 18 is provided so as to extend from the center of the conductive grinding tool 16 toward the outer diameter direction from the side surface of the negative electrode 18 to the opposite side surface.

The rotary rocking shaft of the conductive grinding tool 16 and the negative electrode 18 are connected to a rotary rocking drive mechanism (not shown), and the conductive grinding tool 16 is the conductive grinding tool 1.
6 is connected to a moving mechanism (not shown) that moves 6 in the axial direction of the rotary rocking shaft. Further, the conductive grinding tool 16 is formed of a sintered alloy obtained by mixing abrasive grains such as diamond powder and metal powder such as Cu, Sn, Fe and Ni in a special mixture and heat-treating them. Furthermore, the nozzle 23,
The reference numeral 24 is configured by being connected to a supply source (not shown) of the weak electric coolant 22 and having a control unit (not shown) for controlling the supply amount and the like.

In the grinding method using the apparatus having the above-mentioned structure, the work surface 15 of the conductive grinding tool 16 is machined to the work piece 1
While contacting the work surface 14 of No. 1 and rotating and swinging the same about the spherical center O, the weakly electrically conductive coolant 22 is supplied from the nozzles 23 and 24, and further, the electrically conductive grinding tool 16 from the electrolytic dressing power source 21. The workpiece surface 14 of the workpiece 11 is ground while supplying a current to the negative electrode 18.

According to this embodiment, the nozzle 2 is operated during the grinding process.
The weakly conductive coolant 22 supplied from No. 4 spreads over the entire surface of the negative electrode 18 in a form of being guided to the groove 17, and the entire machined surface 15 of the conductive grinding tool 16 is electrolytically dressed uniformly. Grinding can be performed continuously.

The conductive grinding tool 16 is not limited to the material of this embodiment, and for example, abrasive grains such as diamond powder and metal powder such as Cu, Su, Fe, Ni or conductive resin is used as a binder. It is also possible to use a grindstone.

[0019]

Second Embodiment FIG. 5 is a schematic plan view of an apparatus used in this embodiment. In this embodiment, the nozzle 24 in the first embodiment is used.
The discharge port of the weak electric coolant is directly connected via the tube 31 and the manifold 32 when the weak electric coolant in the groove 17 of the negative electrode 18 enters. The other structure is the same as that of the first embodiment, and the same reference numerals are given and the description thereof is omitted.

In the grinding method using the apparatus having the above-mentioned structure, when the weakly electric coolant enters the groove 17 formed in the negative electrode 18, the weakly electric coolant is directly connected and supplied, so that the conductive grinding tool 16 is machined. The weak electric coolant surely enters between the surface 15 and the negative electrode 18, and the weak electric coolant spreads along the groove 17 over the entire surface of the negative electrode 18.

According to this embodiment, as compared with the first embodiment,
Further, uniform and efficient electrolytic dressing can be performed, and accurate grinding can be continued.

[0022]

Third Embodiment FIG. 6 is a side sectional view of an apparatus used in this embodiment. In this embodiment, the negative electrode 18 in the first embodiment is used.
The groove 17 is formed in the T-shaped groove 41. The other structure is the same as that of the first embodiment, and the same reference numerals are given and the description thereof is omitted.

In the grinding method using the apparatus having the above-mentioned structure, since the groove 41 has a T-shape, the flow rate of the weak electric coolant flowing in the groove 41 is large, and the cathode 18 can be more reliably discharged.
The weak electric coolant can be spread over the entire surface of the. Further, since the groove 41 is T-shaped, the flow rate of the weakly-electrolyte coolant in the groove 41 can be increased without reducing the area of the portion of the negative electrode 18 facing the processed surface 15, thus stabilizing the electrolytic dressing. You can do it.

According to this embodiment, it is possible to continue highly accurate grinding as in the case of the second embodiment.

[0025]

As described above, according to the grinding apparatus and method according to the present invention, the spherical grinding by the subordinate machining method of the optical material is accurately performed by the electrolytic in-process dressing grinding method while uniformly dressing the grinding tool. Grinding can be continued with good stability.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of the present invention.

FIG. 2 is a conceptual diagram of the present invention.

FIG. 3 is a side sectional view showing the first embodiment.

FIG. 4 is a schematic plan view showing the first embodiment.

FIG. 5 is a schematic plan view showing a second embodiment.

FIG. 6 is a side sectional view showing a third embodiment.

FIG. 7 is a configuration diagram of a main part showing a conventional example.

FIG. 8 is a schematic plan view showing a conventional example.

[Explanation of symbols]

 1 conductive grinding tool 2 processing surface 3 negative electrode 4 nozzle 5 weak electric coolant 6 groove

Claims (2)

[Claims] Claim: What is claimed is: 1. An anode is applied to a conductive grinding tool oscillating and rotatably arranged so as to oppose a surface to be processed of a member to be rotatably held, In the electrolytic in-process dressing grinding method, in which a cathode is applied to the electrodes arranged at a predetermined distance, and a workpiece is ground while supplying a weakly electric coolant between the conductive grinding tool and the electrodes, A grinding method, characterized in that grinding is performed while supplying the weakly electric coolant to a groove formed on a surface of the electrode facing the conductive grinding tool. 2. A work holding part for rotatably holding a member to be machined, a conductive grinding tool which is arranged so as to oscillate and rotate so as to face a surface to be machined of the member to be machined, and the conductive grinding. An electrode having a groove formed on the surface facing the machined surface of the tool and arranged at a predetermined distance, a power source for applying an anode to the conductive grinding tool and a cathode to the electrode, and the conductive grinding tool. A grinding device comprising a supply unit for supplying a weakly electric coolant between the electrode and the electrode.