JPH08276363A - Grinding method and its device - Google Patents

Abstract

PURPOSE: To perform electrolytic inprocess dressing when grinding high in efficiency is carried out with its grinding wheel rotated at the high speed. CONSTITUTION: A work 1 is so constituted as to be held by a work chuck 2, and also as to be rotatably driven freely by a spindle 3. A grinding wheel 4 is so held by a spindle 6 capable of being rotated as to be freely rotated. A minus (-) electrode 7 is formed into a disc shape, set in such a way that an interval of 0.1 to 0.5mm is interspaced with the working surface of the grinding wheel 4, and so constituted that the aforesaid electrode can thereby be rotated. A plus (+) electrode 9 is electrically connected with the working surface 5 of the grinding wheel 4. A nozzle 13 is interposed between the working surface 5 of the grinding wheel 4 and the minus (-) electrode 7 in such a way that it can feed weak electric coolant 12. Electrolytic inprocess dressing can thereby be carried out by applying DC pulse current to the respective electrodes 7 and 9 from a power supply 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding method and apparatus for grinding hard and brittle materials such as optical glass and fine ceramics.

[0002]

2. Description of the Related Art Conventionally, as a method of grinding hard and brittle materials such as optical glass and fine ceramics, there is an invention described in Japanese Patent Laid-Open No. 188266/1989. In the above invention, as shown in FIG. 5, the (+) electrode 51 for applying the electrolytic in-process dressing method is connected to the base of the grinding wheel 52. The (-) electrode 53 is the grinding wheel 52.
It is installed facing the machined surface. Further, 54 is a weakly electric coolant supplied between the (-) electrode 53 and the grinding grindstone 52 processed surface.

The apparatus having the above construction supplies the weak electric coolant 54 while rotating the grinding wheel 52, and the (-) electrode 53.
A voltage from the power supply device 55 is applied to the (+) electrode 51. By applying a voltage, the processed surface of the grinding wheel 52 is electrolytically dressed during processing, and grinding is performed without causing the grinding wheel 52 to be clogged.

[0004]

However, the above-mentioned prior art has the following drawbacks. That is, when performing the grinding process, the grinding efficiency is improved by increasing the rotation speed of the grinding wheel to increase the rotational peripheral speed of the grinding wheel. However, in the electrolytic in-process dressing grinding like the conventional example, when the rotational speed of the grindstone is set to a high speed (for example, the peripheral speed of the grindstone is 3000 m / min), between the (−) electrode and the processed surface of the grindstone. An air layer is formed on the surface, the weak electric coolant does not sufficiently reach the dressing region, and the dressing current value decreases, so that stable electrolytic in-process dressing cannot be performed.

It is an object of claims 1 and 2 to provide a grinding method and apparatus capable of performing stable electrolytic in-process dressing grinding even when a grinding wheel is rotated at a high speed for processing.

[0006]

According to a first aspect of the present invention, there is provided a method of dressing a rotationally driven cup-shaped grinding wheel by an electrolytic in-process dressing method, and abutting a rotationally driven workpiece for machining. The grinding method is characterized in that the grinding is performed while reducing the relative speed of the peripheral surface speed of the electrode surface for electrolytic dressing and the grinding grindstone processing surface.

According to a second aspect of the present invention, a surface grinding apparatus is provided with a work holder for rotatably holding a work, a rotationally driven cup-type grinding wheel, and means for dressing the wheel by an electrolytic in-process dressing method. In the above, the grinding device is characterized in that the electrode for electrode for electrolytic dressing is provided with a drive means for reducing the relative speed of the peripheral surface speed of the electrode surface for electrolytic dressing and the surface of the grinding wheel during processing.

[0008]

The action of claim 1 is to suppress the air layer generated during high-speed rotation of the grinding wheel by decreasing the relative speed of the electrode surface for electrolytic dressing and the surface of the grinding wheel that is being machined during processing. And perform stable grinding.

According to a second aspect of the present invention, an air layer generated during high-speed rotation of the grinding wheel is suppressed by reducing the relative speed between the electrolytic dressing electrode surface and the grinding wheel processing surface during processing. Then, the weak electric coolant is stably supplied between the electrode surface for electrolytic dressing and the grinding grindstone processed surface.

[0010]

[Embodiment 1] FIGS. 1 and 2 show the present embodiment, FIG. 1 is a schematic configuration diagram, and FIG. 2 is a view on arrow A in FIG. The work 1 is held by a work chuck 2, and is rotated by a spindle 3 rotatable by a drive device (not shown).
It is configured so that it can be driven and rotated about. The grinding wheel 4 is held by a spindle 6 rotatable by a drive device (not shown) so as to be rotatable about a rotation center a. Further, the work 1 and the grinding wheel 4 are configured to be relatively movable in the arrow Y direction in FIG. 1 by a drive device (not shown).

The grinding whetstone (# 4000) 4 has conductivity, and its processed surface 5 is made of a special mixture of abrasive grains such as diamond powder and metal powders such as copper, tin and iron, and heat treated sintered alloy. It is configured. Reference numeral 7 denotes a (-) electrode for performing the electrolytic in-process dressing method, which is made of copper or carbon graphite. This (-) electrode 7
Is formed in a disk shape, and is used as a processing surface 5 and 0.1 for the grinding wheel 4.
It is installed so as to have a space of 0.5 mm. Further, the (-) electrode 7 is fixed to a rotary shaft of a motor 8 provided near the outer periphery of the processed surface 5 of the grinding wheel 4 and the grinding wheel 4
It is configured to rotate about a rotation axis c parallel to the rotation axis a.

Reference numeral 9 denotes a (+) electrode, which is installed so as to come into contact with the base metal part of the grinding wheel 4 and which is a processed surface 5 of the grinding wheel 4.
Is electrically connected to. 10 is a brush electrode, and this brush electrode 10 is installed so as to be in contact with the (-) electrode 7.

Reference numeral 13 denotes a nozzle, which is connected to a coolant device (not shown) and is installed so as to be able to supply the weakly electrically conductive coolant 12 between the working surface 5 of the grinding wheel 4 and the (-) electrode 7. There is. The (−) electrode 7 and the (+) electrode 9 are connected to a power supply device 11, and are configured so that electrolytic in-process dressing can be performed by applying a DC pulse current from the power supply device 11 to each of the electrodes 7 and 9. ing.

In the apparatus having the above construction, first, the weak electric coolant 12 is supplied between the (-) electrode 7 and the processing surface 5 of the grinding wheel 4 in the same direction as the rotation direction of the grinding wheel 4,
The peripheral speed of the grinding surface of the grinding wheel 4 is 5000 m / min (1
1000 rpm). Next, a DC pulse current is supplied from the power supply device 11 to the (+) electrode 9 and the (-) electrode 7 to perform electrolytic dressing, and the workpiece 1 rotates and comes into contact with the grinding wheel 4 to perform surface grinding. Done.

At this time, the (-) electrode 7 is driven by the motor 8.
Is rotated in the direction opposite to the rotating direction of the grinding wheel 4. That is, in the facing portion where the processed surface 5 of the grinding wheel 4 and the (-) electrode 7 are overlapped with each other, they are rotated so that their respective rotation directions are the same direction (see FIG. 2). (-) The number of rotations of the electrode 7 is a speed (15000 r) at which the relative speed to the processed surface 5 of the grinding wheel 4 is 1000 m / min in the facing portion.
pm) and rotate.

According to this embodiment, the grinding wheel has a peripheral speed of 100.
Even when rotating at a high speed of 0 m / min or more,
The relative speed between the (-) electrode and the processed surface of the grinding wheel is maintained at an optimum speed for electrolytic in-process dressing.
Therefore, stable electrolytic in-process dressing can be performed even when performing high-efficiency processing by rotating the grinding wheel at high speed.

In the present embodiment, the rotation axis of the (-) electrode 7 is provided in the vicinity of the outer periphery of the processing surface 5 of the grinding wheel 4, but the present invention is not limited to this, and the rotation axis of the (-) electrode 7 is not limited to this. The same effect can be obtained even if the rotary shaft is installed inside the processing surface 5 of the grinding wheel 4. In that case, the rotation directions of the (-) electrode 7 and the grinding wheel 4 are set to be the same.

[0018]

[Embodiment 2] FIGS. 3 and 4 show the present embodiment, FIG. 3 is a schematic configuration diagram, and FIG. 4 is a view on arrow B of FIG. In this embodiment, a fin is provided on the upper surface of the (-) electrode 7 in the first embodiment, which guides the weak electric coolant to the dressing area, and the installation position of the nozzle 13 for supplying the weak electric coolant is changed. Differently, other configurations are composed of the same components, and the same components are designated by the same reference numerals and the description thereof will be omitted.

On the upper surface of the (-) electrode 7 of this embodiment, fins 14 for guiding the weakly electrically conductive coolant 12 to the dressing area are formed. Further, the nozzle 13 is installed at a position where it is easy to supply the weak electric coolant to the fin 14.

In the apparatus having the above-mentioned structure, the weakly electric coolant 12 supplied from the nozzle 13 is supplied to the dressing area at high speed by the fins 14 on the upper surface of the (-) electrode 7. The other actions are similar to those of the first embodiment, and the description thereof will be omitted.

According to this embodiment, the same effect as that of the first embodiment can be obtained, and since the weak electric coolant is surely supplied to the entrance of the dressing area, high efficiency machining by high speed rotation of the grinding wheel can be performed. Even when it is performed, more stable electrolytic in-process dressing can be performed.

[0022]

According to the effects of the first and second aspects, stable electrolytic in-process dressing can be performed when a grinding wheel is rotated at a high speed to perform highly efficient grinding.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram illustrating a first embodiment.

FIG. 2 is a view on arrow A in FIG.

FIG. 3 is a schematic configuration diagram showing a second embodiment.

FIG. 4 is a view on arrow B of FIG.

FIG. 5 is a schematic configuration diagram showing a conventional example.

[Explanation of symbols]

 1 Work 2 Work Chuck 3,6 Spindle 4 Grinding Wheel 5 Processing Surface 7 (-) Electrode 8 Motor 9 (+) Electrode 10 Brush Electrode 11 Power Supply Device 12 Weakly Electric Coolant 13 Nozzle

Claims (2)

[Claims] 1. A method for dressing a rotationally driven cup-type grinding wheel by an electrolytic in-process dressing method and abutting against a workpiece that is rotationally driven for processing, and an electrode surface for electrolytic dressing and grinding wheel processing during processing. A grinding method characterized in that the grinding is performed by reducing the relative speed with respect to the peripheral speed with respect to the surface. 2. A surface grinding apparatus provided with a work holder for rotatably holding a work, a rotationally driven cup-shaped grinding wheel, and means for dressing the grinding wheel by an electrolytic in-process dressing method during processing. A grinding device, characterized in that a driving means for reducing a relative speed of a peripheral speed of an electrode surface for electrolytic dressing and a surface to be processed by a grinding wheel is provided on the electrode for electrolytic dressing.