JPH03170266A - Electrolytic dressing method and device - Google Patents

Abstract

PURPOSE:To keep good grinding efficiency over a long period by electrifying an electrode in connection to a power cathode and an abrasive grain layer in connection to a power anode while setting a dressing jig back and forth to a stone so that a resistance value between the electrode and the abrasive grain layer or a pole-to-pole voltage value can be within a given range. CONSTITUTION:The end at least of an electrode 16 is coated with insulator 15 to form a slit 18, which is large enough to put in the outer periphery of a stone 10 to be given dressing, at the end of the insulator 15. A dressing jig 14 for which the end face of an electrode 16 is exposed is arranged on the bottom face of the slit 18, and the outer periphery of the stone 10 is arranged in the slit 18 in such a manner that the end face of the insert electrode 16 is faced to the grinding face of the stone at a constant space. Next, electrolytic grinding liquid is supplied in between the electrode and the grinding face, and a resistance value between the electrode and an abrasive grain layer or a pole- to-pole voltage value is measured by measurement 21, 23, to electrify the electrode in connection to a power cathode and the abrasive grain layer in connection to a power anode while setting the dressing jig back and forth to the stone so that this value can be within a given range.

Description

DETAILED DESCRIPTION OF THE INVENTION ``Industrial'' Second Field of Application The present invention relates to a method and apparatus for electrolytically draining a grinding wheel using a conductive binder.

``Prior art'' When cutting or grinding hard and brittle materials such as silicon, ferrite, and ceramics, superabrasive grains are used as abrasive grains to increase the wear resistance of the grinding wheel.
Metal bonded grindstones or electroformed grindstones using metal as a bonding agent are often used.

3. By the way, when using this type of metal bonded grinding wheel or electroformed grinding wheel, when cutting hard and brittle materials such as those mentioned above, the superabrasive grains wear out faster than the bonding agent, and the grinding process occurs early after the start of grinding. There was a problem in that the cutting edge of the superabrasive grain on the grinding surface became flattened, the amount of protrusion became smaller, and the sharpness deteriorated.

For this reason, in the past, in order to restore sharpness, SiC
A method has been adopted in which dressing is performed by applying a dressing grindstone using abrasive grains such as A. or A.I.t.o.a.

However, with this method, the superabrasive grains are damaged along with the binder, resulting in severe abrasion of the abrasive grain layer and significantly shortening the life of the grinding wheel.The dressing operation also limits the operating rate of the grinder, reducing work efficiency. There were drawbacks that led to a decline.

Therefore, as shown in FIG. 5, some methods have been proposed in which the ground surface is electrolytically drained in parallel with the grinding.

Reference numeral 1 in the drawing denotes a disc-shaped cutting grindstone, which is attached to a spindle shaft 2 of a grinding machine, and an electrode 3 is arranged to cover the outer circumference of the grindstone 1.

This electrode 3 is entirely made of metal such as copper, and consists of a pair of crescent-shaped side plates 3A and a top plate part 3B that fixes these side plates 3A in parallel.
is connected.

Then, while rotating the grinding wheel 1 and grinding the workpiece W, by connecting the anode of the power source to the spindle shaft 2 of the grinding wheel 1 and the cathode to the electrode 3, and simultaneously supplying electrolyte from the liquid supply path 4, The metal binder in the abrasive grain layer of the rotating grindstone 1 is gradually eluted.

According to this method, since only the binder is removed while leaving the abrasive, it is possible to promote blade formation and maintain good sharpness without damaging the superabrasive grains.

[-Problems to be Solved by the Invention] However, in the dressing method described in Section 2, the anode is directly connected to the grinding wheel l, and the electrode 3 has the side plate portion 3A. Dressing also progresses on the side surfaces.

For this reason, when this method is applied to ultra-thin blade grindstones that are used for processing semiconductor devices, etc., the thinning of the grindstone cannot be ignored, resulting in drawbacks such as a decrease in cutting width accuracy.

In addition, in the above method, since the gap between the electrode 3 and the grinding wheel 1 must be set to a relatively large value of several ffff to several ci, the effect of modifying the shape of the grinding fil + the unevenness of the grinding wheel is It was so low that truing had to be done separately.

``Means for Solving the Problems'' The present invention has been made to solve the following two problems.Firstly, the electrolytic dressing method of the present invention covers at least the tip of the electrode with an insulator. A dressing jig is formed by forming a slit in the tip of the insulator into which the outer circumference of the whetstone to be dressed can fit, and exposing the tip of the electrode at the bottom of the slit, and inserting the outer circumference of the whetstone into the slit. The tip surface of the inserted electrode is arranged so as to face the grinding surface of the grindstone at a certain distance, and an electrolytic grinding limb is provided between the electrode and the grinding surface,
Measure the resistance value or inter-electrode voltage between the electrode and the abrasive grain layer, and while moving the draining jig forward and backward with respect to the grinding wheel so that this value falls within a certain range, set the electrode as a power cathode and the abrasive grain layer as a power anode. It is characterized by being connected and energized.

Note that the slits may be formed by covering the tip of the electrode with an insulator prior to electrolytic dressing and cutting into the insulator with a grindstone to be used for dressing.

- On the other hand, in the electrolytic dressing device of the present invention, the tip of the electrode is covered with an insulator, a slit is formed in the tip of the insulator into which the outer periphery of the grinding wheel can be inserted. a drainage jig in which the tip of the electrode is exposed on the bottom surface of the grinding jig, a distance detection mechanism for measuring the resistance value or voltage between the electrodes and the abrasive grain layer; a spacing adjustment mechanism that supports the dressing jig so as to face each other and advances or retreats the dressing jig toward the grinding wheel according to an output signal from the spacing detection mechanism; The present invention is characterized in that it is equipped with a liquid supply means for supplying electrolytic grinding fluid and a power supply mechanism that supplies electricity with the electrode as a cathode and the abrasive grain layer as an anode.

In addition, the said dressing jig may be equipped with the limb feeding path which opens into the said slit as a limb feeding means.

"Function" According to the electrolytic dressing method and device described above, the dressing speed can be feedback-controlled by adjusting the amount of current, so by performing dressing simultaneously with grinding, the abrasive wear rate on the grinding surface can be increased. It is possible to balance the dressing speed and grinding speed, and it is possible to maintain good grinding efficiency over a long period of time.

In addition, since the sides of the abrasive grain layer of the grinding wheel are electrically shielded by the walls on both sides of the slit, almost no current flows through the side surfaces of the abrasive grain layer, and the sides of the abrasive grain layer are rarely dressed. . Therefore, thinning of the abrasive grain layer is prevented, and constant cutting accuracy can be maintained over a long period of time.

8 In addition, since the position of the dressing jig is controlled by detecting the resistance value or inter-electrode voltage between the abrasive grain layer and the electrode, the gap between the grinding surface and the electrode can be maintained at an accurate, extremely small constant value. is easy. Therefore, the elution rate of the binder changes sharply in accordance with the irregularities of the ground surface, and the effect of modifying the shape of the ground surface is high.

In addition, the dressing jig has a slit open to the inside.
When a liquid supply path is formed and the electrolytic grinding liquid is supplied through this supply path, the electrolytic grinding liquid can be effectively supplied fJ (fJ) even into the narrow gap between the electrode and the grinding surface, increasing the dressing efficiency. At the same time, the metal ions eluted from the grinding surface are quickly discharged, and the binding agent is prevented from depositing again on the electrode surface and inhibiting dressing.

Embodiment FIG. 1 is a schematic diagram showing an embodiment of an electrolytic drainage apparatus according to the present invention.

The reference numeral 10 in the figure is a cutting whetstone such as a metal bond whetstone, an electroformed whetstone, or an electroplated whetstone using a conductive binder.
A work W fixed to a spindle shaft +1 of a grinding machine and fixed on a work table I2 is cut while supplying grinding fluid from a nozzle l3.

On the other hand, reference numeral I4 denotes a dressing jig, which, as shown in FIG. 2, is composed of a rectangular parallelepiped-shaped insulator 15 and an elongated plate-shaped electrode I6 horizontally buried inside this insulator 15. . In addition, a liquid supply hole l7 is formed in the center of the insulator I5 in parallel with the electrode 16, and a slit l8 with a width that allows the outer circumference of the grinding wheel 10 to fit almost without any gap is formed in the center of the tip surface of the insulator 15. A portion of the tip surface of the electrode I6 is exposed at the bottom surface of the slit 18.

In order to form such a slit 18, as shown in FIG. 4, after embedding the electrode l6 inside the insulator I5 with only the base end exposed, a position where the tip of the electrode 16 is exposed is created. Grind with a grinding wheel lO until dressing. According to this method, it is easy to form the slit I8 having a width that matches the thickness of the grindstone.

Note that as the material of the insulator 15, various types of plastics, ceramics, and any other insulating materials may be used, but materials with good machinability are preferred.

The material of the electrode I6 is Ni, Ni-based alloy. Highly corrosion resistant metals such as stainless steel and Ta, carbon and graphite are suitable. Although the illustrated electrode I6 has an elongated plate shape, it is not limited to this shape and may be shaped like a bar, a tube, or a terminal.

Further, the thickness of the electrode l6 is determined depending on the diameter of the grinding wheel and the thickness of the grinding wheel ζ.

The dressing jig 14 is the driving part 2 of the separation amount adjustment mechanism 19.
0, and is supported with the outer peripheral part of the grindstone IO fully inserted into the slit l8.

This spacing adjustment mechanism 19 is equipped with a high-precision stepping motor or the like as a drive source, and moves the dressing jig l4 to the grindstone 10 in accordance with an output signal from an M spacing detection mechanism 24, which will be described later.
advance and retreat toward.

Between the electrode l6 and the spindle shaft 11, an electrode I
A power supply device 22 is connected via an ammeter 21 with 6 as a cathode and the spindle shaft I+ as an anode, and a settable constant current is supplied. The output capacity of the power supply device 22 should be determined in consideration of the type of grinding wheel 0, the required dressing speed, etc., but for a normal grinding wheel, about 50VXIOA is sufficient.

Further, a voltmeter 23 is connected between both poles of the power supply device 22, and this voltmeter 23 is further connected to a separation amount detection mechanism 24. This separation amount detection mechanism 24 operates the M H IJk adjustment mechanism 19 when the voltage between the two poles exceeds a predetermined upper limit (the resistance between the electrode I6 and the grinding wheel 10 increases),
The dressing jig I4 is advanced to a position where the voltage between the electrodes is below the upper limit {j'j.

In addition, the voltage between the electrodes is lower than the lower limit (the electrode 16 and the grinding wheel I
0), the spacing adjustment mechanism 19 is activated to retract the dressing jig I4 to a position exceeding the lower limit value.

To use the second device, the liquid supply hole 17 is connected to a supply pump (not shown), and electrolytic grinding liquid is supplied at a constant flow rate to the gap between the slit 18 and the grindstone IO. and power supply device 22
, the spacing detection mechanism 24, and the spacing adjustment mechanism 9 are operated, the dressing jig 14 is moved, and the electrode l6
The distance between the grinding surface of the grinding wheel lO and the grinding surface of the grinding wheel lO is adjusted to be within a certain range.

The optimum distance between the two differs depending on the type of the grindstone 10, and for example, in the case of an M cast thin blade grindstone, it is set to about 1 to 500 μm, preferably about 5 to 200 μm. If the shoulder is less than 1 μm, a short circuit between the electrode 16 and the grinding wheel IO occurs at the beginning of drenching, resulting in a decrease in dressing efficiency, and the wear of the electrode 16 progresses due to passage of chips, which is undesirable. On the other hand, 500μ
If the size is larger than that, the shape correction effect will decrease, and the grindstone r
The proportion of the Ill surface being dressed increases relatively,
A problem arises in which the draining efficiency of the grinding surface of the whetstone is relatively reduced.

Further, the current density at the tip surface of the electrode 16 is 0. 1~l
00, preferably 0.5-50A/ax'. 0
．． If it is less than IA/cy', sufficient dressing cannot be performed, and if it is more than I O 0 A / ax2, the electrolysis rate of the electrolyte increases, and a dressing effect commensurate with the increase in current cannot be expected.

Is it desirable to energize electrode I6 continuously?
During research r111? Is this intermittent? Almost the same effect can be obtained by doing this. Further, the current may be a direct current as shown in the figure, or an alternating current with an IJ bias, a pulse current, or the like.

As the electrolytic grinding fluid, since the distance between the grinding wheel 10 and the electrode 16 is small, a commonly used grinding fluid with low electrical conductivity can also be used, but in order to increase the dressing efficiency, it is necessary to improve the electrical conductivity. To cheat? 2 No. 3-, CI-,
It is desirable to add an appropriate amount of electrolyte containing SO4' and the like. Furthermore, in order to prevent corrosion of the device body due to the addition of these electrolytes, an inhibitor may be added at the same time.

According to the electrolytic dressing device and method having the above configuration, the dressing speed can be feedback-controlled by adjusting the amount of current applied to the electrode I6, so if the dressing is performed simultaneously with the grinding, the abrasive particles on the grinding surface can be controlled. It is possible to balance wear rate and dressing rate,
Appropriate abrasive grain protrusion amount can be maintained over a long period of time.

Further, since the side surfaces of the abrasive grain layer of the grinding wheel IO are electrically shielded by both side wall surfaces of the slit 18 formed in the insulator I5, the side portions of the abrasive grain layer are less likely to be trained. Therefore, it is possible to prevent the abrasive grain layer from becoming thinner, thereby preventing a decrease in accuracy such as a decrease in cutting allowance due to the thinning.

In addition, since the position of the tracing jig 14 is controlled by measuring the voltage between both poles of the power supply device 22, the grinding surface and the electrode 16 are
It is easy to maintain the gap between the two at an accurate, extremely small constant value. Therefore, the elution rate of the binder changes sharply in response to the unevenness of the grinding surface, and the shape modification effect of the ground surface is high, reducing the need for separate truing. at the same time,
The apparatus can be simplified compared to a configuration in which the resistance value between the grindstone IO and the electrodes 16 is directly measured.

Furthermore, in the above embodiment, a liquid supply hole l7 is formed in the dressing jig (4) between the electrodes I6, and the electrolytic grinding liquid is co-supplied into the slit 18 through this liquid supply hole I7.
Electrolytic grinding fluid can be effectively supplied to the narrow gap between the electrode l6 and the grinding wheel IO, improving dressing efficiency, and
Another advantage is that the metal ions eluted from the grinding surface are quickly discharged and are less likely to precipitate on the exposed portion of the electrode l6.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and the configuration of each part may be changed as required as described below.

For example, in the embodiment -12, the voltage between the electrode 16 and the grinding wheel 1 is measured by measuring the voltage between the two poles of the constant current type power supply device 22.
The resistance with 0 was detected indirectly, but instead,
The jig position may be controlled by directly measuring the resistance value between the spindle shaft II of the grindstone IO and the electrode 16.

Alternatively, the limb supply path 17 may not be formed inside the dressing jig 4, and the liquid may be supplied from the outside.
It is also possible to apply the present invention to grindstones other than disc-shaped grindstones, such as cup-shaped grindstones and inner peripheral edge-type grindstones.

"Experiment example" Next, the effects of the present invention will be demonstrated by giving experimental examples.

(Experimental Example 1) An apparatus similar to that shown in FIG. 1 was used, and in parallel with the grinding, the following dressing of a diamond electroformed grindstone (electroformed Ni bond) was carried out.

I6 Outer diameter + 01111JIX Thickness 0.37Iux Inner diameter 40x
xDiamond 1, abrasive grain diameter 2 0/3 0μ shoulder abrasive grain content 32vol%, cutting edge protrusion 511I! l・As a lessing jig, thickness 2.0 x width 5yixO) S U
An S304 plate was used as an electrode and embedded in epoxy resin with only the base end exposed, and after the resin was cured, a 6xzφ liquid supply hole was formed in the upper part of the electrode in parallel with the electrode.

Furthermore, after connecting a lead wire to the base end of the electrode, the base end was covered with an insulating material.

Next, this dressing jig was fixed to a slicing machine via a spacing adjustment mechanism equipped with a micrometer, and was opposed to the outer periphery of the grindstone so that it could move forward and backward toward the center of the grindstone. Furthermore, a resistance meter was connected between the electrode and the grindstone.

Next, the slining machine was operated, and while rotating the electroformed thin-blade grindstone, the dressing jig was moved toward the grindstone using the spacing adjustment mechanism, and a cut was made into the tip surface of the grindstone. Then, when the resistance meter shows a short circuit, stop cutting, and from that point, use a micrometer to adjust the
It was moved back by μm.

Next, the electrode was connected to the cathode of a DC constant current power source, the spindle was connected to the anode, a liquid supply nozzle was fixed to the tip of the liquid supply hole, and a liquid supply pump was connected to the base end of the liquid supply hole.

After completing the above two preparations, a grinding experiment was conducted under the following grinding and dressing conditions.

Work material: AL03/TiC material, vertical 75mm x width 75mm x thickness 4mm Feed speed: 30m/min. Depth of cut: 4.51111F Pitch: Iui Total grinding distance: 5 25 ash Grinding liquid 2 parts Water + Small amount of inhibitor 10 N aN O 3 1 0 9/ Q Dressing current + 0.09 A Distance between electrode and grinding machine M: 5 ~50μm As a result, the cutting resistance in the normal direction is II kg at the initial stage of cutting.
After showing W, 0. It was stabilized at 6 k9W. 52
The radius wear of the electroformed thin-blade grindstone after 5-butt cutting was 34 μm, and the range of maximum chipping variation at each cutting line on the surface of the workpiece was within a very narrow range of 20 to 25 μR.

In addition, when the shape change of the cutting edge was half cut into another workpiece made of the same material, and the cross-sectional shape of the groove formed was reduced, the thin wall of the grinding wheel due to wear at a position 2 0 0 717+ from the tip of the cutting edge. The amount of carbonization was only around 12μ.

Next, after correcting the cutting depth of the grinding wheel for wear, the position of the draining jig is optimized, and a new workpiece of the same material is cut again under the same grinding conditions as above, and these operations are repeated. The work material was cut five times.

Kerf width, cutting resistance, maximum tipping after each cut is completed,
The amount of thinning and the amount of cumulative wear in the radial direction at a position 200μ shoulder from the tip of the cutting edge were measured. The result is the first
Shown in the table. Note that the measurement was performed at the center of the final cutting line of each workpiece.

(Comparative Example 1) Instead of the training jig in Experimental Example 1, a rectangular dressing grindstone (WC400/Bil/Refined grindstone) with a width of 15 mm and a thickness of 15 mm was used at the front end of the same workpiece as described above. The dressing grindstone was placed along the cutting line, and the cutting material was cut under the same cutting conditions as above, and the dressing grindstone was cut at each cutting line. In this way, the work material 1
Five workpieces were cut while correcting the depth of cut after each workpiece.

Table 1 shows the results of measurements on the same items as in the above experimental example.

(Left below) 20 (Example 2) A device similar to that shown in Figure 1 was created, and the following diamond metal bond grinding wheel (Bond F: 85wt%Cu
+15+vt%Sn) dressing was performed.

Outer diameter 1011IllIx Thickness 1. Ozix inner diameter: 40 ■ Diamond abrasive grain size: 40/60 μ, abrasive grain content: 25 vol%, cutting edge protrusion: 10 mm As a tracing jig, a carbon plate with a thickness of 5.0 mm and a width of 5 am is used as an electrode, and only the base end is exposed. After the resin hardens, a part of the electrode is parallel to the electrode (6z).
A liquid supply hole of zφ was formed. Furthermore, after connecting a lead wire to the base end of the electrode, the base end was covered with an insulating material.

Next, this dressing jig was fixed to the slicing man via a spacing adjustment mechanism equipped with a micrometer, and was opposed to the outer periphery of the grindstone so that it could move forward and backward toward the center of the grindstone. Furthermore, a resistance meter was connected between the electrode and the grindstone.

Next, the slicing machine was operated, and while the metal bond grindstone was being rotated, the redressing jig was moved toward the grindstone using the spacing adjustment mechanism, and a cut was made into the tip surface of the grindstone.

Then, when the ohmmeter shows a short circuit, stop cutting,
From that position, the dressing jig was moved back 300 μm using a micrometer.

Next, the electrode was connected to the cathode of a DC constant current power source, the spindle was connected to the anode, a liquid supply nozzle was fixed to the tip of the liquid supply hole, and a liquid supply pump was connected to the base end of the limb supply hole.

Next, rotate the whetstone, operate the liquid supply pump to supply grinding IYI+1 from the liquid supply nozzle, set the current value of the DC stabilized power supply to 0.15A, and apply electricity between the electrodes. The voltage was measured. For the obtained voltage value +2V, set the upper voltage limit of the DC power supply to +4V and the lower limit to IIV, and during grinding, operate the distance m adjustment mechanism according to these upper and lower limit values to adjust the distance between the grinding surface of the grinding wheel and the electrode. The structure was designed to keep the amount constant.

After completing the above two preparations, a grinding experiment was conducted under the following grinding and draining conditions.

Work material: AI, 03 material, vertical 200 rtrm x horizontal 120 ii x thickness 5
xM feed rate: 30 xR/min Depth of cut: 6.5 ■ Bitch: 21l total grinding distance・IOi Grinding fluid, city water + small amount of inhibitor + NaCI 5g/12 Dressing current: 0.1 5A As a result, method The cutting resistance in the linear direction is 2I kg at the beginning of cutting.
After showing W, it became constant at about 1.5 kgW.

The radius wear amount of the metal bond grindstone after 10JI cutting is 36
The variation range of maximum chipping at each cutting line of 8 μm on the surface of the workpiece was in a very narrow range of 30 to 35 μm.

In addition, when we investigated the change in the shape of the cutting edge by making a half-cut into another workpiece made of the same material and looking at the cross-sectional shape of the groove formed, we found that the amount of thinning of the grinding wheel due to wear at a position 500 μm from the tip of the cutting edge was It was only 22μ.

(Comparative Example 2) Instead of the dressing jig in Experimental Example 2, a rectangular dressing grindstone (width 15RxX thickness + 5zz) was used.
A WC220 vitrified grindstone) was placed along the front edge of the same workpiece as above, and the workpiece was cut under the same cutting conditions as above, and a dressing grindstone was cut for each cutting line.

As a result of measuring the same items as in the above experimental example, the cutting resistance in the normal direction was 2.4 kgW at the initial stage of cutting, and then 3.5 kgW at a cutting distance of 3 m. IkgW, 4.8kgW at 6m, 10M
The power consumption was 5.9k9W, which gradually increased as the cutting distance increased.

Radius wear force of metal bond grinding wheel after Ion cutting is 580
It was μM. The maximum chipping variation range at each cutting line on the surface of the workpiece was 35 to 50 μM.

Further, the amount of thinning of the grindstone due to wear at a position 500 μn from the tip of the cutting edge was 45 μm.

(Experimental Example 3) An apparatus similar to that shown in FIG. 1 was prepared, and in parallel with the grinding, the following dressing of a diamond electroformed grindstone (electroformed Ni bond) was performed.

Outer diameter 76.2111J! X thickness 0. I3zuX inner diameter 40
mm Diamond abrasive grain size: 8/16 μl Abrasive grain content 32 vol%, cutting edge protrusion 3 zm As a dressing jig, a Ni plate with a thickness of 1.0 cm and a width of 522 cm was used as an electrode, with only the base end exposed, and placed in epoxy resin. buried in
After the resin had hardened, a liquid supply hole with a diameter of 6 sides was formed on the top of the electrode in parallel with the electrode. Furthermore, after connecting a lead wire to the base end of the electrode, the base end was covered with an insulating material.

Next, this Dressong jig was fixed to the slicing mason via a spacing adjustment mechanism equipped with a micrometer, and was opposed to the outer periphery of the grindstone so that it could move forward and backward toward the center of the grindstone.

Next, connect the electrode and spindle to the DC stabilized power supply in the same way as above, and set the current value to 0.04A and the voltage value to 16.
V, the slicing machine was operated while applying electricity between the two poles, and while the electroformed thin-edged grindstone was being rotated, the dressing jig was moved in the direction of the grindstone using the spacing adjustment mechanism, and a cut was made into the tip surface of the grindstone. . Then, when a current flowed between the two electrodes and the voltage between the two electrodes dropped, indicating a short circuit, the cutting was stopped, and the dressing jig was retreated 50 μm from that position using a micrometer. Next, a limb supply nozzle was fixed to the tip of the liquid supply hole, and a liquid supply pump was connected to the base end of the limb supply hole.

After completing the above preparations, a grinding experiment was conducted under the following grinding and dressing conditions.

Work material. Mirror-polished H IF ferrite (bonded to table with wax) 20 uix length x 50111 lx width x 2u thickness feed speed. 20
■/min Depth of cut 2.5x1l Pitch: 0.5mm Total number of cutting lines 90 (lines) x l00 (work material) Grinding K1 Niichi Mizuju inhibitor small amount + NaN 0 35 0 9/ i2 Dreso song current: 0.04A The above test was conducted five times, and in each case, the set value of 9000 lines could be cut without causing any peeling or scattering of the work material from the alloy.

(Comparative Example 3) A cutting test was conducted five times under the same conditions as in Experimental Example 3 without using the draining jig in Experimental Example 3 above.

As a result, in all cutting tests, the work material peeled off and scattered from the alloy before reaching the set value, and the average number of cutting lines until the work material was scattered was 826 lines.

"Effects of the Invention" As explained above, according to the electrolytic dressing method and apparatus according to the present invention, the following excellent effects can be obtained.

■ Dressing speed can be feedback-controlled by adjusting the amount of current, so by performing dressing at the same time as grinding, it is possible to balance the abrasive wear rate on the grinding surface and the dressing speed, resulting in a long-term Good grinding efficiency can be maintained throughout.

■ Since the sides of the abrasive grain layer of the grinding wheel are electrically shielded by both side walls of the slit 1, almost no current flows through the side surfaces of the abrasive grain layer, and the sides of the abrasive grain layer are rarely dressed. . Therefore, thinning of the abrasive grain layer can be prevented and good grinding accuracy can be maintained over a long period of time.

■ Since the position of the dressing jig is controlled by detecting the resistance value between the abrasive grain layer and the electrode, it is easy to maintain the gap between the grinding surface and the electrode at an accurate, extremely small constant value. Therefore, the dressing strength changes sharply in response to the unevenness of the grinding surface, and the effect of modifying the shape of the grinding surface is high.

■ If a feeding path that opens inside the slit is formed in the dressing jig and electrolytic grinding fluid is supplied through this feeding path, the electrolytic grinding fluid can be effectively supplied to the narrow gap between the electrode and the grinding surface. This not only improves the dressing efficiency but also provides the advantage that metal ions eluted from the grinding surface are quickly discharged and are less likely to be deposited on the electrode surface.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an embodiment of the electrolytic tresting device according to the present invention, Figs. 2 and 3 are longitudinal cross-sectional views and front views showing a treading jig of the same device, and Fig. 4 is a slit forming FIG. 3 is a longitudinal cross-sectional view showing the previous dressing jig. On the other hand, FIG. 5 is a schematic diagram showing a conventional electrolytic lending method. W... Work material, IO... Grinding wheel, I1... Spindle shaft, 14 ・Draining jig, I5 ・Insulator, I
6.Electrode, 17.Liquid supply hole (liquid supply path), 18.Slit, ■9.M distance adjustment mechanism, 20.Drive unit, 21.
・Ammeter, 22...Power supply mechanism, 23...Voltmeter, 2
4... Separation amount detection mechanism.

Claims (4)

[Claims] (1) A method of electrolytically dressing the ground surface of the abrasive layer while rotating a grindstone having an abrasive layer using a conductive binder around its axis, the method comprising: coating at least the tip of the electrode with an insulator; A slit into which the outer circumference of the whetstone to be dressed can fit is formed at the tip of this insulator, and a dressing jig consisting of exposing the tip of the electrode at the bottom of the slit is inserted into the slit to fit the outer circumference of the whetstone. Insert the part so that the tip surface of the electrode faces the grinding surface of the grindstone at a constant distance, and supply electrolytic grinding fluid between the electrode and the grinding surface,
Measure the resistance value or inter-electrode voltage between the electrode and the abrasive grain layer, and while moving the dressing jig forward and backward with respect to the grinding wheel so that this value falls within a certain range, set the electrode as a power cathode and the abrasive grain layer as a power anode. An electrolytic dressing method characterized by connecting each and applying electricity. (2) Prior to the electrolytic dressing, the tip of the electrode is covered with an insulator, and the slit is formed by cutting the insulator with a grindstone to be dressed. Electrolytic dressing method. (3) A device for electrolytically dressing the ground surface of the abrasive layer while rotating a grindstone having an abrasive layer using a conductive binder around an axis, the tip of the electrode being covered with an insulator. A dressing jig is provided, in which a slit is formed at the tip of the insulator into which the outer circumferential portion of the grinding wheel to be dressed can fit, and the tip surface of the electrode is exposed at the bottom of the slit, and the electrode and the abrasive layer are A separation amount detection mechanism that measures the resistance value or voltage between the electrodes, and a dressing jig that supports the dressing jig so that the tip end surface of the electrode faces the grinding surface of the grindstone, and responds to the output signal from the separation amount detection mechanism. a distance adjustment mechanism for moving the dressing jig forward and backward toward the grindstone; a liquid supply means for supplying electrolytic grinding fluid to the gap between the electrode and the grinding surface; and a supply means for supplying electricity with the electrode as a cathode and the abrasive grain layer as an anode. An electrolytic dressing device characterized by comprising a power supply mechanism. (4) The electrolytic dressing device according to claim 3, wherein the dressing jig includes a liquid supply path opening into the slit as a liquid supply means.