JPH01121172A - Grinding attachment equipped with electric discharge forming area for blade edge - Google Patents

Abstract

PURPOSE:To make a blade edge surface highly accurately electric discharge formable into a desired form without removing a blade from a grinding attachment as well as without causing deflection and deformation by an electric discharge forming area for a blade edge in this grinding attachment. CONSTITUTION:A workpiece (for example, a magnetic head) is clamped to a chuck table in a grinding attachment for a dicing device or the like, and a blade is cut into the workpiece, while a work table, where a chuck table is set up, is relatively moved in three axial directions of X, Y and Z to the blade, and the workpiece is machined. When an edge of the blade 3 worn out with this machining is discharged formed, an electrode 12 with a negative form wall surface conformed to an edge form of the blade 3 is clamped to the chuck table 8 as an electric discharge forming area. Next, the blade 3 attached to a spindle 4 of the grinding attachment is approached to the wall surface of the electrode 12, and a pulse voltage is impressed on an interval between both, so that a blade edge surface is discharge formed into a desired form.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a grinding device that performs grinding processing such as dicing, and particularly relates to a grinding device equipped with a discharge forming region on a blade edge.

[Conventional technology]

Grinding processes such as grooving and cutting of magnetic heads and the like are performed by a grinding device using an extremely thin blade. This type of grinding requires high precision, so if the cutting edge of the blade is worn out and its shape is deformed, it must be dressed immediately to restore the shape to its original correct shape. There is.

As this type of blade edge forming device, the device shown in FIG. 10 is known. In this device, a dresser (for example, a grindstone made of green carborundum) 2 is fixed to the tip of a spindle 1 that can move forward and backward, and is rotated at high speed in an oblique direction with respect to a rotating blade (grindstone) 3 for grinding, for example. By pressing the dresser 2 and scraping off the shaded area A, then rotating the spindle 1 by φ and pressing the dresser 2 from the opposite diagonal direction, and similarly scraping off the shaded area B, the cutting edge of the blade 3 is shaped like a ■ character, for example. It is formed into a shape.

[Problem that the invention seeks to solve]

However, since the blade edge forming device described above must have a space for rotating the spindle 1 by φ, the device becomes large and it is difficult to incorporate this blade edge forming device (dresser) into a grinding device such as a dicing device. Because of this difficulty, it was necessary to form this as a separate device from the grinding device.

For this reason, when forming (dressing) the cutting edge of a blade, it is necessary to remove the blade from the grinding device and attach the removed blade to the cutting edge forming device, which creates the problem of complicating the work. there were.

In addition, as mentioned above, since the cutting edge formation (dressing) is performed by removing the blade from the grinding device, when the blade is reattached to the spindle of the grinding device after processing, the blade is likely to be misaligned, which can lead to grinding such as dicing. There was a problem in that it adversely affected precision machining.

Furthermore, since the cutting edge is formed while the blade is pressed by the dresser, the blade is likely to be processed in a bent state, which poses an obstacle to forming the cutting edge accurately.

The present invention has been made to solve the above-mentioned conventional problems, and its purpose is to provide a grinding device with a small cutting edge forming area so that the cutting edge can be formed without removing the blade from the grinding device. To provide a grinding device equipped with a discharge forming region of a cutting edge, which can dress the blade without bending and deforming the blade, and form an accurate cutting edge shape.

[Means for solving problems]

In order to achieve the above object, the present invention is configured as follows. That is, the present invention provides X, Y,
A chuck table capable of rotational movement for fixing a workpiece is disposed on a work table capable of relative movement in three Z-axis directions, and a discharge forming area of a blade edge is provided on the work table. It is structured with the following characteristics:

[For production]

In the present invention configured as described above, grinding of a workpiece such as a magnetic head is performed by fixing the workpiece to a chuck table, cutting the blade into the workpiece in this state, and moving the work table to the blade. This is done by moving relative to the other person.

If the cutting edge of the blade is worn out during this grinding process and becomes rounded, electrical discharge formation on the cutting edge is performed as follows. For example, an electrode having a female-shaped wall surface corresponding to the shape of the cutting edge of a blade is fixed to a chuck table of a grinding device as a discharge forming region, and a blade attached to a spindle of the grinding device is brought close to the wall surface of the electrode. do.

In this state, if a pulse voltage is applied between the blade and the electrode while supplying electrical discharge machining fluid between the blade and the electrode, an electric discharge will occur between the two, and the cutting edge of the blade will match the wall shape of the electrode. This will result in the formation of a correct cutting edge surface.

61 〔Example〕 Embodiments of the present invention will be described below based on the drawings.

1 and 2 show a first embodiment of a grinding device according to the present invention.

In the figure, a conductive blade 3 in which abrasive grains are formed by electrodeposition is mounted and fixed on a spindle 4 of a grinding device such as a dicing device. This spindle 4 has an output shaft 4b fitted into an outer cylindrical portion 4a via an insulating member, and the output shaft 4b is connected to the rotor side of a motor 5 and rotatably supported by an air bearing or the like. has been done.

Although the shape of the cutting edge of the blade 3 is V-shaped in the drawing, it is not necessarily limited to this shape, and as shown in FIG. Various options can be selected depending on the situation.

On the other hand, a first chuck table 7 and a second chuck table 8 are fixed to a work table 6 of the grinding device so as to be rotatably movable in the θ direction. A vacuum suction hole (not shown) is formed inside the first chuck table 7, and this vacuum suction hole is operated by a vacuum pump (not shown).
is communicated with. A workpiece 10 such as a wafer or a magnetic head is fixed to the upper surface of the chuck table 7 by vacuum suction.

On the other hand, the second chuck table 8 is fixed to the work table 6 via an insulating member 11, and the second chuck table 8 also has a vacuum suction hole that communicates with a vacuum pump (not shown) inside. and using this vacuum suction hole,
An electrode 12 is fixed to the upper surface of the chuck table 8 by vacuum suction to form a discharge forming area. Note that the holding means for the electrode 12 may be any means other than suction as long as it can hold the electrode 12; for example, the electrode 12 may be fastened and fixed using an electromagnetic chuck, a bolt, or the like. The electrode 12 is made of a plate-like material such as iron or tungsten.
As shown in FIG. 3, a wall surface 13 corresponding to the shape of the cutting edge of the blade 3 is formed on the surface thereof by grooves 14. In Fig. 3, the cutting edge of the blade 3 has a V-shape, so the wall surface 13 also has a female V-shape, but as shown in Fig. 4, when the cutting edge has a different shape, , the wall surface 13 is formed as a female slope corresponding to the shape.

By the way, in FIG. 1, the work table 6 can move freely in the three axes of X, Y, and Z relative to the blade 3, and the movement in the three axes of x, y, and z is performed by a computer, etc. Similarly, the θ rotational movement of the chuck table 7.8, the amount of forward/backward movement of the spindle 4, and the rotational speed of the output shaft 4b are also controlled by the same control device 15. The output shaft 4
b is electrically connected to the carbon brush 16, and furthermore, this output shaft 4b is electrically connected to the blade 3. The carbon brush 16 is connected to a positive terminal of a pulse generator 17, and a negative terminal of the pulse generator 17 is connected to the electrode 12 via a second chuck table 8. This pulse generator 17 has a blade 3 and an electrode 1.
Since a pulse voltage is applied between 2 and 2, the magnitude of the pulse voltage (in this example, 5 to 10
Discharge conditions such as V), frequency (5 MHz in this embodiment), pulse duty ratio (25% in this embodiment), etc. are given by commands from the control device 15.

Further, a current detection sensor (in this embodiment, an ammeter) 18 is provided between the pulse generator 17 and the blade 3, and this detects the momentary discharge current, and this current detection signal is sent to the control device 15. is being sent to. The control device 15 is
Based on this detected current value, the pulse voltage is controlled and the distance between the blade 3 and the electrode 12 is adjusted as necessary.

In addition, 20 in the figure indicates water or other electric discharge machining between the blade 3 and the electrode 12? It is a nozzle for feeding the night.

The embodiment device of the bookcase 1 is constructed as described above, and its operation will be explained below.

First, during grinding, a workpiece 10 such as a magnetic head material is attracted and fixed to the first chuck table 7 . In this state, move the work table 6 in the desired direction of X and Y, place the workpiece IO to face the blade 3, and cut the workpiece 10 into the desired direction. Cutting and grooving are performed. During this grinding process, no pulse voltage is supplied from the pulse generator 17, and the pulse orderer 17 is in a stopped state.

During this grinding process, if the cutting edge of the blade 3 is worn out and deformed, for example, if the V-shaped cutting edge becomes rounded as shown in Fig. 3, move the work table 6. Then, the electrode 12 is made to face the blade 3, and the cutting edge of the blade 3 is formed (dressed).

In this case, the electrode tool 2 is correctly fixed at a fixed position on the second chuck table 8 using a microscope or the like, and information on the positions x, y, z, and θ is sent to the control device 15 to attach the electrode 12. It has been entered. The attachment of this electrode 12 is based on the groove 14 of the electrode 12 and the blade 3.
The cutting edges of the blades are opposed to each other as shown in FIG. 3 (more specifically, one side 3a of the blade edge is located directly above the wall surface 13a of the groove 14).

In this state, the blade 3 is rotated while supplying electrical discharge machining fluid from the nozzle 20, and the blade 3 is moved in the X direction while the electrode 12 is relatively reciprocated in the Y-axis direction.
When the blade edge 3 and the electrode 12 are brought closer to each other and a pulse voltage is simultaneously applied between the blade edge 3 and the electrode 12 from the pulse generator 17, a discharge is started between the blade edge 3a and the wall surface 13a of the electrode 12. The discharge current at this time is detected by the current detection sensor 18, and the detection signal is sent to the control device 15. The control device 15 controls the X,
A discharge start position in the direction is determined, and the amount of cutting is calculated and set based on this discharge start position, that is, the set-up position. Then, the electrode 1 is
2 in the direction of the blade 3 (X direction) (In this case, if necessary, send the blade 3 in the X direction.
), electric discharge continues to progress between the cutting edge surface 3a of the blade 3 and the wall surface 13a of the electrode 12, and the rounded part 19a on one side of the cutting edge is scraped off by this electric discharge, and the rounded part 19a on one side of the cutting edge of the blade 3
a is an inclined surface along the wall surface 13a of the electrode 12.

Next, when the blade 3 is moved toward the opposite wall surface 13b (in the X direction), electric discharge similarly progresses between the blade edge surface 3b and the wall surface 13b, the rounded portion 19b is scraped, and the blade edge surface 3b is moved from the wall surface. It becomes an inclined surface along 13b. As a result, blade 3
The cutting edge is formed into the original sharp V-shape in preparation for the next grinding process.

-a, in dressing with this cutting edge shape, the cutting allowance of the rounded portions 19a, 19b is very small, several microns, and therefore, the distance between the cutting edge surfaces 3a, 3b and the wall surfaces 13a, 13b during the discharge progresses. Since the spacing never becomes large enough to destabilize the spacing, there is little need to adjust the spacing during electrical discharge machining.

On the other hand, for example, as shown in FIG. 5, when a V-shaped cutting edge is formed by electric discharge using a disk-shaped blade 22, the cutting allowance becomes large, and therefore, as the electric discharge progresses, Blade edge surfaces 3a, 3b and wall surfaces 13a, 13b
If the distance between the two ends becomes too large, the discharge state may become unstable. In such a case, the control device calculates the distance between the two based on the detection signal from the current detection sensor, moves the blade 22 or the electrode 12 side in the X direction based on the calculated value, and adjusts the distance between the two to an appropriate distance. need to be maintained.

According to the first embodiment, since the electrode 12 can be formed very small, it is possible to mount this electrode 12 on the second chuck table 8 of the grinding machine, so that the blade 3 can be moved from the spindle 4. It is possible to form the cutting edge without removing it. When forming the cutting edge by removing the blade 3 from the spindle 4 as in the past, the blade 3
When the blade 3 is attached and detached, the blade 3 is displaced, but in the case of the first embodiment, such a problem does not occur, thereby making it possible to carry out highly accurate grinding.

In addition, since the cutting edge can be formed in a non-contact manner by electric discharge, no bending force is applied to the cutting edge of the blade 3.
The cutting edge can be formed into the correct shape, which leads to improved accuracy in grinding processes such as dicing.

A second embodiment of the invention is shown in FIG. The embodiment of the wood brush 2 is different from the first embodiment -14= The first chuck table 7 is omitted, and the second chunk table 8 serves both as the grinding area and the discharge forming area of the blade edge. The other configurations are the same as those of the first embodiment.

In this second embodiment, grinding such as dicing of the workpiece 10 is performed by suctioning and fixing the workpiece 10 to the second chuck table 8. Then, when forming the cutting edge of the blade 3, the electrode 12 is sucked and fixed to the chuck table 8 instead of the workpiece IO, and the cutting edge is formed by electrical discharge in the same manner as in the first embodiment. In this second embodiment, in addition to obtaining the same effects as the first embodiment, there is an advantage that the apparatus can be made smaller by omitting the first chuck table 7.

A third embodiment of the invention is shown in FIG. In the third and third embodiment, the electrode 12 is formed in the shape of a roller, and as shown in FIG. This embodiment is characterized in that a driving motor 21 is disposed on the work table 6 to provide a discharge forming area, and the other configurations are the same as those of the first and second embodiments. in this case,
The negative terminal of the pulse generator 17 and the roller electrode 12 are electrically connected through appropriate means.

By forming the grooves 14 on the circumferential surface of the roller in this way, the cutting edge surfaces 3a and 3b of the blade 3 are formed during electric discharge formation on the cutting edge.
This can be carried out by rotating the electrode 12 with a motor while facing the wall surface 13a or 13b of the groove 14 at a fixed interval. Therefore, wall surfaces 13a and 13b
The entire circumferential surface of the electrode 120 is used as the electrode wall surface for electric discharge machining, and local wear of the electrode 120 can be avoided, thereby making it possible to accurately form the shape of the cutting edge.

FIG. 9 shows a fourth embodiment of the invention. This embodiment is characterized in that an abrasive grain layer 23 is formed on the surfaces of the groove wall surfaces 13a and 13b of the electrode 12, and the other configurations are the same as those of the first to third embodiments.

This abrasive grain layer 23 is obtained by electrodepositing abrasive grains such as diamond or CBN using conductive nickel or copper as a base metal, for example.

If the abrasive grain layer 23 is formed in this way, the blade edge can be formed by electrical discharge using the electrode 12 with this abrasive grain layer 23 attached, and then the blade edge surfaces 3a and 3b can be rubbed against the abrasive grain layer 23. , a so-called new cutting edge can be exposed on the cutting edge surface. That is, during discharge formation at the cutting edge, the base metal (abrasive grain binder) and electrode on the surface of the cutting edge are often melted and evaporated by the discharge heat, and after the discharge is completed, this may harden to cover the cutting edge, which is undesirable. In such a case, after the discharge formation is completed, the cutting edge surface is coated with the abrasive grain layer 2 on the electrode 12 side.
3, the molten solidified material such as the base metal falls off, and a new cutting edge can be exposed on the surface of the cutting edge.

Furthermore, by providing the abrasive grain layer 23 on the electrode 12 side, when forming the blade edge, the blade edge surfaces 3a and 3b are brought into light contact with the groove wall surfaces 13a and 13b of the electrode (more specifically, the wall surface of the abrasive grain layer 23) and rubbed. Discharge formation can be performed in this state. In other words, a combined process of dressing the cutting edge by rubbing the abrasive grain layer 23 and forming electric discharge between the electrodes is performed, and the efficiency of forming the cutting edge can be greatly improved.

Furthermore, by forming the abrasive grain layer 23 on the electrode 12,
Efficiently performs electrical discharge formation on the blade edge surfaces 3a and 3b after grinding (cutting, grooving, etc.) a non-conductive workpiece)
You can get the benefit of being able to. That is, after grinding a non-conductive workpiece, the non-conductive chips adhere to the cutting edge surfaces 3a, 3b, and the electrical discharge conditions between the cutting edges 3a, 3b and the wall surfaces 13a, 13b. This causes problems such as destabilization (for example, non-uniform discharge voltage). In this case, chips can be removed from the cutting edge surfaces 3a, 3b by rubbing the cutting edge surfaces 3a, 3b after grinding the non-conductive workpiece. By performing electric discharge formation on the blade, the blade edge surfaces 3a and 3b can be dressed under stable electric discharge conditions.

Furthermore, in each of the above embodiments, explanations have been given mainly regarding blades having a V-shaped cutting edge as a representative example, but the present invention can also be applied to forming any other arbitrary cutting edge shape, as shown in FIG. This also applies to

Further, in each of the above embodiments, the electrical discharge machining fluid is supplied between the blade 3 and the electrode 12 by the nozzle 20, but unlike this, for example, the electrical discharge machining fluid is placed in a water tank, and the blade cutting edge is placed in the fluid. The discharge formation may be performed while the electrode I2 is immersed.

〔Effect of the invention〕

As explained above, the present invention is a grinding device such as a dicing device in which a discharge forming region is formed on the cutting edge.
The cutting edge can be formed without removing each blade from the grinding device, and this cutting edge forming work can be facilitated.

Furthermore, the problem of positional deviation of the blade relative to the spindle due to attachment and detachment of the blade can be completely avoided, making it possible to perform highly accurate grinding.

Further, since the blade edge is formed almost non-contact by electric discharge, the blade edge is not pressed strongly against the electrode. Therefore, during discharge formation, the blade edge is bent and deformed due to the force applied to it, and there is no problem caused by conventional devices in which the blade edge shape cannot be formed correctly, and as a result, the accuracy of blade edge formation can be further improved. can.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a configuration diagram showing a first embodiment of the present invention, FIG. 2 is a side view of FIG. 1 showing the arrangement relationship between the first and second chuck tables, and FIG. The figure is a sectional view showing the discharge formation area of the same embodiment, FIG. 4 is an explanatory view showing various examples of the blade edge shape and the corresponding female-shaped electrode wall surface, and FIG. 5 is a plate-shaped blade. 6 is a block diagram showing the second embodiment of the present invention, and FIG. 7 is a block diagram showing the third embodiment of the present invention. ,
Fig. 8 is a detailed view showing the discharge forming area of the same embodiment, Fig. 9 is a main part configuration diagram showing the fourth embodiment of the present invention, and Fig. 10 is an example of blade edge formation using a conventional dressing device. FIG. ■...Spindle, 2...Dresser, 3...Blade, 3a, 3b...Blade edge surface, 4...Spindle,
4a... Outer circumferential cylinder portion, 4b... Output shaft, 5... Motor, 6... Work table, 7... First chuck table, 8... Second chuck table, 10...・・・
Workpiece, 11... Insulating member, 12... Electrode, 1
3.13a, 13b-wall surface, 14...groove, 15...
-Control device, 16... Carbon brush, 17... Pulse generator, 18... Current detection sensor, 19.19a
, 9b-rounded portion, 20... nozzle, 21... motor, 22... blade, 23... abrasive grain layer. Applicant Disco Co., Ltd. Patent attorney Kiyoshi Igarashi = 20-

Claims (6)

[Claims] (1) A rotatable chuck table that fixes the workpiece is installed on a work table that can move relative to the blade in the three axes of X, Y, and Z, and on the work table 1. A grinding device equipped with a discharge formation region on a blade edge, characterized in that a discharge formation region is provided on a blade edge. (2) The discharge forming area of the blade edge is formed by disposing an electrode having a female-shaped wall surface corresponding to the shape of the blade edge on a work table. A grinding device equipped with a discharge forming region on a cutting edge as described in 2. (3) The discharge forming area of the cutting edge is formed by detachably attaching an electrode having a female-shaped wall surface corresponding to the cutting edge shape of the blade to a chuck table, and the chuck table is connected to the processing area of the workpiece. Claim 1, characterized in that the blade edge also serves as a discharge forming area.
A grinding device equipped with a discharge forming region on a cutting edge as described in 2. (4) A patent claim characterized in that the electrode is made of a conductive plate-like body, and the female-shaped wall surface corresponding to the shape of the cutting edge of the blade is carved in the form of a groove on the surface of this plate-like body. A grinding device comprising a discharge forming region of a cutting edge according to item 2 or 3. (5) The electrode is composed of a conductive roller rotated by a motor, and a female-shaped wall surface corresponding to the cutting edge shape of the blade is provided around the surface of the roller. A grinding device comprising a discharge forming region on a cutting edge according to Scope 2. (6) Any one of claims 2 to 5, characterized in that the female-shaped wall surface of the electrode is formed by electrodeposition of abrasive grains on a conductive metal surface. A grinding device comprising a discharge forming region on a cutting edge as described in .