JPH01153272A - Forming method for electrode of discharge dressing - Google Patents

Abstract

PURPOSE:To readily and exactly form the irregularity corresponding to the shape of the rotary outer circumferential face of a grinding wheel at the end face of an electrode by feeding the flat end face of the electrode toward the grinding wheel while in rotating and bringing this end face into contact with the rotary outer circumferential face of the grinding wheel. CONSTITUTION:A grinding wheel drive motor 4 is driven to rotate a grinding wheel 3 perpendicularly. An electrode 25 is lowered toward the upper rotary outer circumferential face of the grinding wheel 3 while in rotating by rotating the servo motor 14 of a discharge dressing device 6 in the normal direction to bring the flat lower end (end face) of the electrode 25 into contact with the upper outer circumferential face. This contact makes the grinding wheel grind the end face of the electrode 25. In addition, the electrode 25 is further lowered by a given dimension to form the irregularity corresponding to the groove of the rotary outer circumferential face of the grinding wheel 3 on the lower face of the electrode 25. When the abrasive grains of the grinding wheel 3 wear due to grinding of a workpiece 2 with this grinding wheel 3, electric discharge occurs between the electrode 25 and grinding wheel 3, and the metal bond in the abrasive grain section 5 of the grinding wheel 3 is thoroughly eliminated by this discharge energy for dressing abrasive grains and also removing clogged grinding chips.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is applicable to metal bond, diamond grindstone, metal bond CBN used for grinding ceramics and cemented carbide.
This invention relates to a method for creating electrodes for discharge dressing of grindstones, etc.

(Prior art) The dressing of the grinding wheel (sharpening of the grinding grains) is as follows:
T where the metal bond forming the matrix part is strong
Second, it is difficult and takes a long time.

Recently, a method has been developed that uses electric discharge machining to dress this type of grinding wheel and removes the metal bond using electric discharge energy from an electrode (for example, Japanese Patent Publication No. 46-31
Publication No. 276).

(Problems to be Solved by the Invention) In the above-mentioned dressing method, in order to cause a discharge phenomenon, it is necessary to provide a predetermined gap between the tip end surface of the discharge electrode and the rotating outer peripheral surface of the grindstone. When a groove is formed on the rotating outer circumferential surface of the rotor, corresponding unevenness is formed on the discharge electrode side, and if the gap between the two is not uniform, good discharge will not occur. Therefore, it is not possible to completely dress the outer peripheral surface of the whetstone.

Conventionally, when forming irregularities on the tip surface of an electrode, the electrode is ground beforehand outside the machine, but this process requires accurate matching to the shape of the rotating outer peripheral surface of the grindstone. It takes a lot of time and effort.

Furthermore, when attaching the electrode to the machine body, it is necessary to adjust the position of the electrode with the grindstone, which is a very troublesome task.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to simplify the process τ1 of creating irregularities corresponding to the shape of the rotating outer circumferential surface of the grindstone on the distal end surface of the discharge electrode.

Means for Solving Problem C) In order to achieve the above-mentioned object, the gist of the present invention is to grind the tip end surface of the radiating tortoise pole to the grindstone itself to be dressed.That is, the present invention In this method, an electrode whose initial shape is a block is placed on the outside of a disk-shaped metal bond grinding wheel that is vertically rotatably arranged above the grinding machine bed and has circumferential grooves carved on its outer peripheral surface. The tip surface thereof is positioned opposite to the rotating outer circumferential surface of the grindstone, and while the grindstone is rotating, the electrode is advanced at a predetermined feed rate to bring the tip surface into contact with the rotating outer circumferential surface of the grindstone. The method is characterized in that the electrode is successively advanced by a predetermined distance to transfer and create an electrode having a predetermined shape.

(Structure) Hereinafter, the present invention will be described in detail based on examples. The drawings show an apparatus for implementing the present invention; FIG. 1 is a front view, FIG. 2 is a front view showing the lower end surface of the electrode being ground by a grindstone, and FIG. 3 is a longitudinal sectional view of the discharge dressing device. be.

In the figure, (1) is a grinding machine bed that can freely reciprocate in the front-back direction in Fig. 1, and the top surface of the grinding machine bed (1) has a material to be ground (
2) is fixedly placed. A disc-shaped grinding wheel (3) is disposed in the upper head of the grinding machine bed (1) with its axis of rotation perpendicular to the moving direction of the grinding machine bed (1). It is made vertically rotatable by a motor (4). On the rotating outer peripheral surface of the grindstone (3),
Diamond, CB with metal bond as matrix
An abrasive part (5) in which abrasive grains such as N are dispersed and fixed is attached to a predetermined thickness, and several grooves are cut in the circumferential direction of the abrasive part (5).

A discharge dressing device (6) is located above the grindstone (3).
is installed. Now, to explain the configuration of the device (6) in detail, C7) is a cylindrical case;
is fixed at a predetermined level via an arm member (8), and its openings at both ends are closed by a cover (9) and a lower cover (10), respectively. The center and bottom of the upper lid (9)! Through holes (11) (!2) each having a predetermined diameter are bored at appropriate locations in (10).

Above the upper lid (9), a motor mounting bracket (1
A servo motor (14) capable of forward and reverse rotation is disposed at the bottom via a motor (14), and the motor (14) is electrically connected to a controller (not shown). (15) is a shaft holding plate that is loosely fitted into the cylindrical case (7), and a through hole (16) is vertically bored in the center of the plate (15). (16) is provided with a threaded groove. (17) is a ball screw screwed into the through hole (16) of the shaft holding plate (15) through a thread carved on the outer periphery, and the upper end of the ball screw (17) is connected to the upper lid (9). ) protrudes from the through hole (11) of the servo motor C via the coupling (18).
14), and when the ball screw (17) rotates forward or reversely due to the drive of the motor (14), the shaft holding plate (15) is fixed to the rotating shaft (19) of the case (7). Designed to descend or ascend within.

(21) is a guide rod that is loosely inserted into a guide hole (22) that is vertically penetrated through the shaft holding plate (15), and its upper end is connected to the upper cover (9), and its lower end is They are attached to the lower cover (10) and prevent the shaft holding plate (15) from rotating together with the ball screw (17). (23) is an electrode holding shaft, the upper part of which is the shaft holding plate, and the through hole (2) bored in (15).
4) and is internally fixed to the plate (15) by a set screw (not shown). F of the electrode holding shaft (23)
The part slides through the through hole (12) of the lower cover (10) and projects out of the case (7), and the lower end thereof has a block-shaped electrode (25) that is flat downward. ) is fixed. The electrode (25) is electrically connected to a power source for electrical discharge machining (not shown), and can be given either negative or positive polarity. Further, the abrasive grain portion (5) of the grindstone (3) is also electrically connected to the electric discharge machining power source, and positive or negative polarity is given to the abrasive grain portion (5). Further, a grinding fluid is sprayed into a gap provided between the lower end surface of the electrode (25) and the upper rotating outer circumferential surface of the grindstone (3).

In the embodiment, the electrode (25) is disposed close to the upper rotating outer circumferential surface of the grindstone (3), but may be disposed close to the side rotating outer circumferential surface of the grindstone (3). .

(Function) In the apparatus configured as described above, the process of creating unevenness on the lower surface of the electrode (25) corresponding to the grooves on the rotating outer circumferential surface of the grindstone (3) will be explained. )
to vertically rotate the grindstone (3). Second, when a controller (not shown) outside the machine is operated to operate the servo motor (14) of the discharge dressing device (6) in normal rotation, the ball screw (17) rotates and the shaft holding plate (1
5) is lowered at a predetermined feed rate, and along with this, the electrode holding shaft (23) and electrode (25) are lowered. The electrode (25
) will eventually come into contact with the upper rotating outer peripheral surface of the grindstone (3), and will be ground by the grindstone (3). Thirdly, the electrode (25
) continues to descend and reaches a predetermined level, the rotation of the servo motor (14) is stopped and the descent of the electrode (25) is stopped. At this time, in order to dress the grinding wheel (3) with the electrode (25) whose bottom surface is uneven as described above, the servo motor (14) is first operated in reverse, and the electrode (25) is The grinding wheel is raised to a predetermined level, thereby providing a predetermined gap between the lower surface of the electrode (25) and the rotating outer peripheral surface of the grindstone (3).

Next, when the material to be ground (2) is fixedly placed on the grinding machine bed (1) and the bed (1) is fed and moved at a predetermined speed,
The upper surface of the material to be ground (2) is ground by the grindstone (30).

When the abrasive grains of the whetstone (3) are worn out due to the above grinding work,
A grinding fluid is injected into the gap between the lower surface of the electrode (25) and the upper rotating outer circumferential surface of the grindstone (3), and a predetermined amount of electricity is applied from an electrical discharge machining power source (not shown). When the voltage at the electrode (25) rises to a predetermined value, the insulation of the grinding fluid is broken and discharge occurs, and this discharge energy creates a matrix (metal bond) in the abrasive grain portion (5) of the grinding wheel (3). is removed (removed).

At this time, since the abrasive grains are not removed because they are non-conductive, the abrasive grains are dressed (dressed) and at the same time, the clogged grinding powder is also removed.

(Effects of the Invention) According to the present invention as described above, the electrode is a block body with a flat tip surface in the initial state, and the tip surface is ground by the grindstone itself to be dressed. The unevenness corresponding to the shape of the rotating outer circumferential surface is easily and accurately formed.

In addition, as in the embodiment, if the electrode is placed outside the rotating outer circumferential surface of the grindstone to be dressed, and the servo motor allows it to advance and retreat by any desired distance, the servo motor can be rotated in the normal direction when creating the shape. Simply move the electrode forward and press the tip of the electrode against the grindstone, and when dressing the grindstone after shape creation, the servo motor can be reversed to move the electrode back by a predetermined distance ( This eliminates the need for troublesome alignment adjustments with the grindstone.

[Brief explanation of the drawing]

The drawings show an apparatus for implementing the present invention; FIG. 1 is a front view, FIG. 2 is a front view showing the lower end surface of the electrode being ground by a grindstone, and FIG. 3 is a longitudinal sectional view of the discharge dressing device. be. (1): Grinding machine bed (3): Grinding wheel (5): Abrasive grain section (6): Electric discharge dressing device (25)
: Electrode-tei 1 reason, enemy 2, figure 3, prisoner

Claims (1)

[Claims] It is arranged vertically rotatably above the grinding machine bed (1),
In addition, an electrode (25) whose initial shape is a block is placed on the outside of a disk-shaped metal bonded grindstone (3) with circumferential grooves carved on the outer circumferential surface of the rotation, and its tip surface is attached to the outer side of the grindstone (3). The electrode (25) is positioned opposite to the rotating outer circumferential surface, and while the grindstone (3) is rotating, the electrode (25) is advanced at a predetermined feed rate so that its tip surface comes into contact with the rotating outer circumferential surface of the grindstone (3). At the same time, the electrode (25) is successively advanced by a predetermined distance to transfer and create an electrode having a predetermined shape.