JP3345538B2 - Electrolytic dressing grinding method and equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for electrolytic dressing grinding, and more particularly, to a method for stabilizing a nonconductive film on a conductive grindstone surface during a mirror finishing process and a roughing process suitable for each processing step. The present invention also relates to an electrolytic dressing grinding method and apparatus for grinding while maintaining an appropriate state.

[0002]

2. Description of the Related Art In a grinding process, phenomena such as an increase in grinding resistance due to crushing or clogging of a grindstone or a seizure of a work material occur, which is a problem in grinding (hereinafter referred to as machining). In recent years, to solve such problems,
An electrolytic dressing (sharpening) method of a conductive grindstone as disclosed in JP-A-1-188266 has been put to practical use.

Japanese Patent Application Laid-Open No. Hei 1-188266 discloses that a conductive grinding wheel is used as a positive electrode, a negative electrode is provided slightly apart from the grinding wheel, and a water-soluble conductive material is used as a grinding fluid between the positive electrode and the negative electrode. In this method, a voltage is applied between the electrodes while flowing the abrasive grinding fluid, and the grindstone is processed by electrolysis to dissolve the binder (bond material) of the grindstone and dressing. However, in the above-mentioned dressing method, the grinding fluid and the components of the grindstone by electrolysis generate a non-conductive film of metal oxide on the work surface of the grindstone. In particular, in the case of a grindstone using a bonding material containing iron as a main component, the processing is performed in a state in which a nonconductive film is formed on the surface of the grindstone on which the processing action is exerted. The non-conductive film impedes the dissolution of the bond material and reduces the effect of dressing.On the contrary, if there is no buffer material such as a non-conductive film on the grindstone surface, the grindstone can be used for mirror finishing. However, there is a problem that the bonding material and the workpiece come into direct contact with each other, and the phenomenon of roughening and seizure occurs.

Japanese Patent Application Laid-Open No. 4-164570 discloses a non-conductive film in a grinding fluid so that the amount of the non-conductive film is always kept in an appropriate state in accordance with the type of processing such as roughing and finishing. The present invention relates to an electrolytic dressing method of controlling the amount of a removed component.
It is described that it is advisable not to form a nonconductive film on the surface of the grindstone during rough processing to medium finishing processing, and it is better to cover the grindstone surface with a nonconductive film during mirror finishing.

[0005]

According to the experiments of the present inventor, in the mirror finishing by the electrolytic dressing method, in order to obtain a machined surface having a small surface roughness, there is a problem in relation to the size of the abrasive grains. The function of the conductive film is particularly important, and the role of the nonconductive film is also important during roughing and medium processing.If a nonconductive film is not generated, the work material and the grinding wheel base contact directly. As a result, it was found that the processed surface was heated by frictional heat and turned black.

According to the present invention, it is possible to obtain an effect suitable for each processing step in electrolytic dressing grinding by making a nonconductive film stable and proper at the time of mirror finish processing or rough processing. That is, in the mirror finishing, it is an object to stably realize a high-quality processed surface having a small surface roughness and a highly efficient processing during the roughing.

[0007]

According to the present invention, there is provided an electrolytic dressing grinding method in which a voltage is applied to a conductive grindstone in the presence of a conductive grinding fluid, and the grindstone is processed while being dressed by electrolysis. Mirror finishing is performed while maintaining the thickness of the non-conductive film formed on the surface of the grindstone by electrolysis to be equal to or greater than the abrasive grain size held in the non-conductive film.

According to a second aspect of the present invention, in the first aspect of the present invention, the diameter of the abrasive grains held in the non-conductive film formed on the surface of the grinding stone is set to 10 μm or less, and the diameter of the abrasive grains is set to 10 μm or less. The mirror finish processing is performed.

A third aspect of the present invention is an electrolytic dressing grinding method in which a voltage is applied to a conductive grindstone in the presence of a conductive grinding fluid to perform processing while dressing the grindstone by electrolysis. The thickness of the non- conductive film formed on the surface of the grindstone is held in the non-conductive film.
Roughing is performed while keeping the abrasive grain size below the specified value.

[0010] In a fourth aspect of the present invention, in the third aspect of the present invention, 40 μm or more is held at a base portion of the bond material under the non-conductive film formed on the surface of the whetstone, which is not affected by the electrolytic action. Roughing is performed using abrasive grains having a diameter of

According to a fifth aspect of the present invention, in the first aspect of the present invention, the thickness of the non-conductive film formed on the surface of the conductive grindstone is controlled to be always constant. It is designed to be processed while processing.

According to a sixth aspect of the present invention, in the grinding process according to the fifth aspect of the present invention, the intensity of electrolysis is controlled while monitoring the thickness of the non-conductive film formed on the surface of the conductive grindstone. Wherein the thickness of the nonconductive film is always constant.

According to a seventh aspect of the present invention, in the invention according to any one of the first to sixth aspects, the electrode is adjusted in accordance with the retreat of the base under the nonconductive film formed on the surface of the conductive grindstone. Is moved in the direction of the conductive grindstone so as to keep the distance between the electrode for electrolysis and the matrix of the grindstone constant.

According to an eighth aspect of the present invention, in the seventh aspect of the present invention, the amount of retreat of the base under the nonconductive film formed on the surface of the conductive grindstone is measured by an eddy current type displacement sensor. Things.

According to a ninth aspect of the present invention, in the invention according to any one of the first to eighth aspects, while monitoring a change in the concentration of halogen ions contained in the conductive grinding fluid used in the electrolytic dressing grinding method, The grinding process is performed.

[0016] The invention of claim 10 is the invention of claim 9, said halide ion Cl ^- as an ion, the Cl ^-
Grinding is performed while maintaining the ion concentration at 30 ppm or less.

The invention according to claim 11 is the invention according to claim 1 to claim 1.
An electrolytic dressing grinding apparatus using any one of the electrolytic dressing grinding methods according to any one of (1) to (3), wherein an eddy current type displacement sensor for measuring a retreat amount of a base under a nonconductive film formed on a surface of the conductive grindstone; And a whetstone driving means for moving the electrode in the direction of the whetstone so as to keep the distance between the electrode for electrolysis and the base of the whetstone constant based on the measurement value of the displacement sensor.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION First, an experiment by the present inventor showing that the function of a non-conductive film is particularly important in the electrolytic dressing grinding method according to the present invention will be described in terms of the configuration of a grindstone. FIG. 1 is a conceptual diagram of a cross section of a grindstone for explaining a grindstone suitable for mirror finishing, in which 11 is a base, 12 is a non-conductive film, 13 is an abrasive grain, and 14 is a working surface. .

The grindstone shown in FIG. 1 comprises a matrix 11 in which abrasive grains 13 are solidified with a conductive and magnetic bonding material, and a nonconductive film 12 formed by oxidation of a bonding material formed by electrolysis. Abrasive grains 13 protrude from the surface of conductive film 12,
It is a working surface 14 and is used for mirror finishing in which the thickness of the non-conductive film 12 is larger than the diameter of the abrasive grains 13.

When the thickness of the non-conductive film 12 shown in FIG. 1 is processed with abrasive grains of a grindstone larger than the diameter of the abrasive grains 13, a processed surface having a small surface roughness is obtained, which is suitable for mirror finishing. The reason is that the strength of the non-conductive film 12 is smaller than that of the grindstone base 11, so that the force holding the abrasive grains 13 is small,
Than when the abrasive grains 13 are held in the mother land 11, because it acts soften the workpiece by non-conductive coating 12 is present thicker than the abrasive particle diameter, the clogging tends to occur grindstone It is considered that clogging does not occur.

FIG. 2 is a conceptual diagram of a grinding wheel cross section for explaining a grinding wheel suitable for rough machining. Parts having the same functions as those in FIG. 1 are denoted by the same reference numerals as in FIG. . FIG.
Is a case where the diameter of the abrasive grains 13 held on the matrix 11 is larger than the thickness of the non-conductive film 12, and the abrasive grains 13 have a larger hardness than the non-conductive film 12. Since it is held on the ground 11, it is suitable for realizing high-efficiency machining as in rough machining. Also in this case, the role of the non-conductive film 12 is important. If the non-conductive film 12 does not exist, the work material and the grindstone base 11 come into direct contact, and the work surface is burnt and blackened. .

Further, according to an experiment conducted by the present inventor, variations in the film quality of the non-conductive film 12 during and after processing greatly affect the processing results. It is important to control the halogen ions. If the halogen ions are not present, the non-conductive film 12 is difficult to grow, and if the halogen ions are too large, the non-conductive film has low adhesion to the base 11 of the grindstone. 1
2 is unnecessarily thick, and stable processing cannot be performed.
Further, it has been found that in order to stabilize the film quality of the non-conductive film 12, it is effective to stabilize the electrolysis by keeping the distance between the matrix 11 of the grindstone and the electrode constant.

FIG. 3 shows an electrolytic dressing grinding apparatus used in an experiment for explaining an embodiment of the electrolytic dressing grinding method according to the present invention.
Is a non-conductive film, 3 is a rotation direction, 4 is an optical stylus displacement meter (laser displacement meter), 5 is an eddy current displacement sensor, 6 is an air gun, 7 is an electrode, 8 is a grinding fluid supply nozzle, and 9 is a power supply. , 10
Is a screen.

In the electrolytic dressing grinding apparatus shown in FIG. 3, the grinding wheel 1 is driven to rotate in the direction of arrow 3, and the eddy current displacement sensor 5, grinding fluid supply nozzle 8, Electrode 7, air gun 6, and 1
0, an optical stylus type displacement meter 4 is arranged, and a positive terminal of a separate DC power supply 9 is connected to the grindstone 1 through a brush (not shown) or the like, and a negative electrode is connected to the electrode 7. Terminal is connected.

The grindstone 1 and the electrode 7 are arranged with a small gap, and at the time of machining, a grinding fluid containing halogen ions is jetted from the grinding fluid supply nozzle 8 toward this gap to perform electrolytic dressing. Optical stylus type displacement meter 4
This is a displacement gauge that measures a change in diameter of the grindstone 1, and is, for example, a laser displacement gauge that utilizes laser light interference. Here, whetstone 1
Is the diameter of the outside including the nonconductive film 2 and is the diameter of the working surface 14 in FIGS. It is necessary that the measuring position at which the grindstone diameter is measured by the optical stylus displacement meter 4 is dry. For this purpose, a front 10 of the optical stylus type displacement meter 4 and an air gun 6 are provided. ing. In addition,
In contrast to the case shown in the figure, the measurement unit can be dried even if the positions of the air gun 6 and the beam 10 are reversed.

On the other hand, the eddy current type displacement sensor 5 is a displacement meter for measuring the surface position of the base 11 of the iron-based magnetic bond by the magnitude of the eddy current, and has a conductive portion which is not affected by the electrolytic action. Measure the diameter of Therefore, the thickness of the non-conductive film 2 can be known by subtracting the measured value of the base diameter of the eddy current displacement sensor 5 from the measured value of the outer diameter of the optical stylus displacement meter 4.

Next, an embodiment for performing mirror finishing using the electrolytic dressing grinding apparatus shown in FIG. 3 will be described. In FIG. 3, the grindstone 1 used for mirror finishing has a diameter of 10 μm or less, but in an experiment, an iron-based bond using abrasive grains of 6 μm or less was used.
20A, and in the initial dressing, the non-conductive film 2
After the thickness of the stainless steel is set to 30 μm, the stainless steel is processed. Since the base of the grinding wheel 1 retreats due to the electrolysis, the displacement measurement value of the eddy current displacement sensor 5 increases. Based on this displacement measurement value, the position of the electrode 7 is advanced toward the grindstone 1 by an amount equal to the amount of retreat of the base, and the base and the electrode 7 are moved forward.
And keep the distance between them constant.

Further, Cl grinding fluid - supplemented grinding fluid concentration by monitoring the concentration of ^(chlorine ions) and the concentration was adjusted so as to 30ppm or less, or to replace the entire. Here, Cl ^- since the concentration does not change rapidly, it is not always necessary to replenish or replace the grinding fluid during processing. However, this Cl ^- concentration is important for stabilizing the processing, Cl to try ^- 30Pp concentration
When the Cl ^- concentration was changed from m to 36 ppm in the direction in which the Cl ^- concentration increased, seizure occurred and processing could not be performed even when processing was performed under the same processing conditions and electrolytic conditions as before.

While the thickness of the nonconductive film 2 was monitored during processing, the thickness of the nonconductive film 2 was reduced due to an increase in the cutting depth on the way. For this reason,
Raise the voltage value of the power supply 9 and increase the thickness of the nonconductive film 2 to 30 μm.
And continued processing. As a result after processing, the surface roughness R
max = 0.09 μm was obtained, and a good mirror-finished surface was obtained.

Next, an embodiment in which rough machining is performed using the electrolytic dressing grinding apparatus shown in FIG. 3 will be described. In FIG. 3, a grindstone 1 is an iron-bronze bond using abrasive grains having an average particle diameter of about 100 μm, and performs rough processing of zirconia ceramics. Electrolysis conditions are 60V, 10A
And The cut was 1 mm. The thickness of the nonconductive film 2 is measured by the same method as in the case of the above-mentioned mirror finishing. Processing is performed by setting the thickness of the nonconductive film 2 to 20 μm. The thickness value of the non-conductive film 2 is read by a personal computer, and when the thickness value of the non-conductive film 2 changes from 20 μm, a system for changing the electrolysis conditions of the power supply 9 by a signal from the personal computer is prepared. . Also, since the base of the whetstone 1 retreats during machining,
Processing was performed while moving the electrode 7 so that the distance between the grindstone base and the electrode 7 was a constant 200 μm, which was larger than the average abrasive particle diameter of 100 μm. Stable processing without clogging was realized.

[0031]

According to the first aspect of the present invention, there is provided an electrolytic dressing grinding method in which a voltage is applied to a conductive grindstone in the presence of a conductive grinding fluid, and the grindstone is processed while being dressed by electrolysis. Since the thickness of the non-conductive film formed on the surface of the grindstone was mirror-finished while maintaining the thickness of the non-conductive film equal to or more than the abrasive particle size held in the non-conductive film, the thickness of the non-conductive film was reduced to the abrasive particle size. With the thickness maintained above, the nonconductive film has a sufficient thickness, prevents the base of the grindstone from being exposed and directly comes in contact with the workpiece, does not cause seizure, and enables stable mirror-surface processing to be continued.

According to the second aspect of the present invention, the diameter of the abrasive grains held in the non-conductive film formed on the surface of the grinding wheel is set to 10 μm or less.
Mirror finish processing with the following abrasive grains, so the processing is performed in a state where a fine grindstone of 10 μm or less is held on the non-conductive film with less strength than the base of the grindstone, and the grindstone acts relatively softly on the workpiece. And it becomes easy to obtain a mirror surface.

According to a third aspect of the present invention, there is provided an electrolytic dressing grinding method in which a voltage is applied to a conductive grindstone in the presence of a conductive grinding fluid to process the grindstone while dressing the grindstone by electrolysis. The thickness of the non- conductive film formed on the surface of the abrasive wheel ,
Roughing is performed while keeping the abrasive grain size equal to or less than that held in the abrasive grain, so that the abrasive grains are projected, the abrasive grains act on the workpiece, and there is no residual cutting, and highly efficient roughing can be performed Become like

According to the fourth aspect of the present invention, in the invention of the third aspect, 40 μm is held at a base portion of a bond material that has not been subjected to electrolytic action under a nonconductive film formed on the surface of the grinding wheel. Roughing is performed with abrasive grains of the above diameter, so it is processed with abrasive grains of 40 μm or more that are firmly held on a strong grinding stone base, so that the abrasive grains work reliably on the workpiece And highly efficient processing can be realized.

Effects corresponding to claim 5: claims 1 to 4
In the invention according to any one of the above, the thickness of the non-conductive film is controlled while controlling the thickness of the non-conductive film formed on the surface of the conductive grindstone to be always constant. By stabilizing the manner in which the abrasive grains act on the workpiece by always keeping the same constant during the processing, the processing can be stably continued.

Effect corresponding to claim 6: In the invention of claim 5, by controlling the strength of electrolysis while monitoring the thickness of the nonconductive film formed on the surface of the conductive grindstone,
Since the thickness of the non-conductive film is always constant during the grinding process, the method of working the abrasive grains on the workpiece by stabilizing the thickness of the non-conductive film during the processing is stabilized. Can also continue stably.

Effects corresponding to claim 7: claims 1 to 6
In the invention according to any one of, according to the retreat of the base under the non-conductive film formed on the surface of the conductive grindstone,
Since the electrode was moved in the direction of the conductive grindstone, so as to keep the distance between the electrode for electrolysis and the base of the grindstone constant,
By keeping the gap between the grinding wheel base and the electrode constant, the electrolysis is stabilized, the thickness of the non-conductive film is easily kept constant, and the processing is stabilized.

According to an eighth aspect of the present invention, in the invention of the seventh aspect, the amount of retreat of the base under the nonconductive film formed on the surface of the conductive grindstone is measured by an eddy current displacement sensor. Therefore, by keeping the distance between the grinding wheel base and the electrode constant, the electrolysis is stabilized, the thickness of the non-conductive film is easily kept constant, and the processing is stabilized.

Effects corresponding to claim 9: claims 1 to 8
In the invention according to any one of the above, while monitoring the change in the concentration of halogen ions contained in the conductive grinding fluid used in the electrolytic dressing grinding method, while performing the grinding process, the film quality of the non-conductive film By controlling the concentration of halogen ions, particularly the concentration of Cl ^- ions, which greatly affects the concentration, a stable electrolysis phenomenon can be obtained for a long time even in mass production, and stable processing can be performed.

According to the tenth aspect, in the ninth aspect, the halogen ion is Cl ^- ion,
The Cl ^- since the grinding while maintaining the ion concentration 30ppm or less, the film quality largely involved the halogen ion concentration of a non-conductive coating, in particular, Cl ^- by managing the concentration of ions, long-term stable electrolysis phenomenon in mass production And stable processing can be performed.

Advantageous Effect Corresponding to Claim 11: Claim 1
An eddy current type displacement sensor for measuring an amount of retreat of a base under a non-conductive film formed on a surface of the conductive grindstone, which is an electrolytic dressing grinding device using any one of the electrolytic dressing grinding methods according to any one of claims 1 to 10. And, based on the measurement value of the displacement sensor, the grinding wheel drive means for moving the electrode in the direction of the grinding wheel so as to keep the distance between the electrode for electrolysis and the base of the grinding wheel constant. By keeping the distance between the base and the electrode constant, the electrolysis is stabilized, the thickness of the non-conductive film is easily kept constant, and the processing is stabilized.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a grinding wheel cross section for describing a grinding wheel suitable for mirror finishing.

FIG. 2 is a conceptual diagram of a grindstone cross section for describing a grindstone suitable for rough machining.

FIG. 3 is an electrolytic dressing grinding apparatus used in an experiment for explaining an embodiment of an electrolytic dressing grinding method according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Whetstone, 2 ... Non-conductive film, 3 ... Rotation direction, 4 ... Optical stylus type displacement meter (laser displacement meter), 5 ... Eddy current type displacement sensor,
6 air gun, 7 electrode, 8 grinding fluid supply nozzle, 9
... power supply, 10 ... appearance (partition), 11 ... home land, 12 ...
Non-conductive film, 13: abrasive grains, 14: working surface.

Claims (11)

(57) [Claims] 1. An electrolytic dressing grinding method in which a voltage is applied to a conductive grindstone in the presence of a conductive grinding fluid to process the grindstone while dressing the grindstone by electrolysis, wherein the electrolysis is performed on the surface of the grindstone by the electrolysis. An electrolytic dressing grinding method, wherein mirror finishing is performed while maintaining the thickness of the non-conductive film at or above the abrasive grain size held in the non-conductive film. 2. The abrasive grains held in a non-conductive film formed on the surface of the grinding stone have a diameter of 10 μm or less.
2. The electrolytic dressing grinding method according to claim 1, wherein mirror finishing is performed using abrasive grains of 0 [mu] m or less. 3. An electrolytic dressing grinding method in which a voltage is applied to a conductive grindstone in the presence of a conductive grinding fluid to process the grindstone while dressing the grindstone by electrolysis. An electrolytic dressing grinding method characterized in that rough processing is performed while maintaining the thickness of the non- conductive film to be carried out to be equal to or less than the abrasive grain size held in the non-conductive film . 4. A rough working is carried out by using abrasive grains having a diameter of 40 μm or more held in a base portion of a bond material which has not been subjected to electrolytic action below a non-conductive film formed on a surface of the whetstone. The electrolytic dressing grinding method according to claim 3, wherein 5. The processing according to claim 1, wherein the processing is performed while controlling the thickness of the non-conductive film formed on the surface of the conductive grindstone to be always constant. Electrolytic dressing grinding method. 6. A method for controlling the intensity of electrolysis while monitoring the thickness of the non-conductive film formed on the surface of the conductive grindstone to keep the thickness of the non-conductive film constant during grinding. The electrolytic dressing grinding method according to claim 5, wherein the grinding is performed. 7. The electrode is moved in the direction of the conductive grindstone in accordance with the retreat of the matrix below the non-conductive film formed on the surface of the conductive grindstone, and the electrode for electrolysis and the grindstone matrix are formed. The electrolytic dressing grinding method according to any one of claims 1 to 6, wherein the distance between the electrodes is kept constant. 8. The electrolytic method according to claim 7, wherein an amount of retreat of the base under the nonconductive film formed on the surface of the conductive grindstone is measured by an eddy current type displacement sensor. Dressing grinding method. 9. The grinding process according to claim 1, wherein the grinding process is performed while monitoring a change in the concentration of halogen ions contained in the conductive grinding fluid used in the electrolytic dressing grinding method. Electrolytic dressing grinding method. 10. The electrolytic dressing grinding method according to claim 9, wherein the halogen ions are Cl ⁻ ions, and the grinding is performed while maintaining the Cl ⁻ ion concentration at 30 ppm or less. 11. An electrolytic dressing grinding apparatus using the electrolytic dressing grinding method according to any one of claims 1 to 10, wherein a retreat amount of a base under a nonconductive film formed on a surface of the conductive grinding wheel. The eddy current type displacement sensor for measuring the displacement sensor, based on the measurement value of the displacement sensor, to move the electrode in the direction of the grinding wheel, so as to keep a constant distance between the electrode for electrolysis and the base of the grinding wheel An electrolytic dressing grinding device comprising a grinding wheel driving means.