JPH1076465A - Grinding machining device and grinding machining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize machining of a small surface roughness and extremely high form precision. SOLUTION: A conductive grinding wheel 2 is disposed to get in contact with a work 3 while rotating for performing grinding machining to it, and at close positions to the grinding wheel 2 to face it, an electrolytic dressing electrode 5 to perform dressing by electrolytic action through processing liquid provided between that and the grinding wheel 2, and an electric discharge machining head 8 to perform truing by electric discharge machining by generating discharge between that and the grinding wheel 2 are provided. Between the grinding wheel 2 and the work 3, between the grinding wheel 2 and the electrolytic dressing electrode 5, and between the grinding wheel 2 and the electric discharge machining head 8, same processing liquid of a volume resistance of 0.1kΩm or more and 10kΩm or less (or favorably, 0.5kΩm or more and 1.5kΩm or less) is supplied from nozzles 11, 12, 13. Dressing and truing can thus be simultaneously performed without disconnecting grinding machining, thereby conditions of the grinding wheel 2 can be maintained to be favorable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding apparatus and a grinding method for performing a grinding process using a grindstone, and more particularly to a process having extremely small surface roughness and capable of performing a process with high shape accuracy. To a grinding apparatus and a grinding method.

[0002]

2. Description of the Related Art In the grinding process, if the surface roughness is to be reduced, a grindstone used is small, that is, a grindstone having a large grindstone is used. Clogging occurs very easily. Therefore, it is difficult to efficiently perform processing with extremely small surface roughness, that is, so-called mirror polishing. As means for solving this problem, for example, there is a technique disclosed in Japanese Patent Application Laid-Open No. 3-196968. In this technique, grinding is performed with a metal bond grindstone using fine abrasive grains, an electrode is provided so as to face a grinding surface of the grindstone, and an electrolytic solution is supplied between the electrode and the grindstone. Then, a voltage is applied between the grindstone and the electrode to perform dressing (sharpening) by an electrolytic action. With this technology, machining debris clogged between abrasive grains can be removed by electrolytic action, eliminating grinding abnormalities such as increased grinding resistance due to clogging of grinding wheels, grinding burns, and scuffing of the machined surface. This enables small processing.

On the other hand, in order to perform grinding with high shape accuracy, it is necessary to perform truing of the grindstone (working of the outer peripheral shape of the grindstone, reshaping) in advance. As the shape processing of the metal bond grindstone, a mechanical processing method such as a method using a diamond truer or a method of co-rubbing with another grindstone is known. However, such a method has a drawback in that a large reaction force acts on the grindstone, thereby causing the misalignment of the grindstone, thereby deteriorating the processing accuracy, or depleting the truer itself so that a desired shape cannot be obtained. there were. Techniques for solving these problems include those disclosed in Japanese Patent Publication No. 2-38346, Japanese Patent Laid-Open No. 3-196968, and Japanese Patent Laid-Open No. 6-210566.

[0004] The technique disclosed in Japanese Patent Publication No. 2-38346 is to reshape (truing) a grindstone by electric discharge machining using a traveling wire. The consumption of the discharge electrode can be reduced to a negligible level. In addition, this technology enables truing on a processing machine that performs grinding,
The removal of the grindstone can be made unnecessary, and the efficiency and accuracy are greatly improved as compared with the conventional method of processing with a dedicated truing machine. However, this method presupposes the use of an NC machine tool because the position of the grinding wheel at the time of grinding and the position of the electrode wire for electrical discharge machining are separated, and in order to perform electrical discharge machining, the grinding wheel is controlled by an NC device. Then, it is moved to a place where electric discharge machining is performed. Therefore, although it is not necessary to remove the grindstone, the processing must be interrupted each time the grindstone is required, and the grindstone must be moved to the position where the wire traveling device is installed to perform the molding. For this reason, the working efficiency is reduced, and the positioning error caused by moving the grindstone over a long distance is increased, resulting in a disadvantage that the processing accuracy is reduced.

[0005] The technique disclosed in Japanese Patent Application Laid-Open No. 3-196968 is to perform truing together with dressing of a grindstone.
A voltage is applied between the electrode and the grindstone with a working fluid interposed in this portion. With such a configuration, an electrochemical action, a chemical action, a mechanical action, and a discharge action work, and truing is performed together with dressing of the grindstone. However, since the electrode is in contact with the grindstone, there is a disadvantage that the electrode is worn out, and that the processing accuracy is deteriorated as in the case of truing by mechanical processing. Therefore, although this technique is mainly effective for dressing (sharpening), truing accuracy is limited, and particularly high-precision processing cannot be expected.

The grinding machine disclosed in Japanese Patent Application Laid-Open No. Hei 6-210566 has a wire electric discharge machine supported so as to be relatively movable with respect to the grindstone, and detects the shape of the grinding surface of the grindstone while detecting the shape of the grindstone. Truing.
That is, the electric discharge machine is supported on a table which can be moved relative to the grinding surface of the grindstone in the width direction and the vertical direction, and detects a discharge start position (discharge start gap) of the wire electrode in the electric discharge machine. You can do it. Thus, a change in the shape of the grinding surface of the grindstone is detected during the grinding of the workpiece, and truing (forming) of the grindstone is performed in accordance with the change. Therefore, truing is performed in response to a change in shape due to wear of the grindstone caused during processing, and it becomes possible to realize grinding with extremely high shape accuracy.

As described above, a technique for performing processing with small surface roughness or processing with high shape accuracy has been conventionally developed, and employs an electrolytic in-process dressing technique described in JP-A-3-196968. As a result, processing with extremely small surface roughness is realized.
By applying the discharge truing technique described in Japanese Patent No. 10566, machining with extremely high shape accuracy is possible.

[0008]

However, a sufficient result cannot be obtained by the above-mentioned prior art for performing grinding with extremely small surface roughness and extremely high shape accuracy. In the technique described in the above-mentioned Japanese Patent Application Laid-Open No. 3-196968, even if truing of the grindstone is performed with high accuracy at first, a minute change occurs in the shape of the grindstone during the grinding while performing dressing. This is due to the fact that the electrolytic action used for dressing acts on the processing waste adhering to the grindstone surface and also affects the grindstone itself. In other words, it acts on the metal bonding material that holds the abrasive grains, dissolves or alters it, and consumes the grinding wheel or changes the diameter of the grinding stone. Is 5μ
It is extremely difficult to perform a precise processing to make the thickness m or less, especially 1 μm or less.

Although it is conceivable to correct such deformation of the grindstone by truing, if the truing is not performed on the grindstone at the position where the grinding process is performed, an error at the time of movement occurs and the above-described error occurs. It has been considered that high precision cannot be obtained and it is difficult to perform both the electrolytic in-process dressing technique and the discharge truing technique on a grindstone at a position where a grinding process is performed. The reason is that the machining fluid interposed between the grindstone and the electrode when performing electrolytic machining is the electrolytic solution, and the machining fluid interposed between the discharge electrode and the grindstone is an insulating machining to generate electric discharge. This is because when these are supplied to the grindstone at the same position, the working liquid is mixed, and normal electrolysis or discharge does not occur.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a grinding apparatus and a grinding method capable of performing processing with small surface roughness and extremely high shape accuracy. It is to provide.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the invention according to claim 1 is directed to a conductive material which is brought into contact with a workpiece while being rotated to perform grinding. A grindstone, a grindstone support means for supporting the grindstone relatively movably with respect to the workpiece, and an electrode close to and opposed to the grindstone, wherein a machining liquid is interposed between the electrode and the grindstone. The present invention also provides a grinding machine having dressing means for performing dressing by an electrolytic action, and an electric discharge machining device which is arranged so as to be close to the grindstone and supported so that the relative position with respect to the grindstone can be adjusted.

In the above configuration, the conductive grindstone contains a conductive material, so that the gap between the grindstone and the electrode for the electric field can be improved.
Alternatively, a voltage can be applied between the grindstone and the electrode for electric discharge machining. For example, a metal bond grindstone in which abrasive grains are solidified with metal can be used. At this time, the abrasive grains may be a conductive material or a non-conductive material.

In such a grinding machine, the grinding can be performed while the rotationally driven grindstone is relatively moved with respect to the workpiece, and the workpiece is processed into a desired shape and dimensions. Becomes possible. Further, since the dressing means is provided opposite to the grindstone supported at the position where the workpiece is ground as described above, when the grindstone is clogged, the dressing is quickly performed. This makes it possible to perform processing with extremely small surface roughness. In other words, by causing an electrolytic action between the electrode and the grindstone, if the grinding dust clogged between the abrasive grains is conductive, the surface of the grinding scrap is directly eluted, and the grinding scrap is removed from between the abrasive grains. Removed. Further, even if the grinding dust is non-conductive, a gas such as oxygen is generated on the surface of the bonding metal of the abrasive grains, the grinding dust is removed by the expansion pressure of the bubbles, and dressing is quickly performed.

Further, an electric discharge machining apparatus is provided so as to be close to and opposed to the grindstone at the position where the grinding is performed, and when a change in the shape of the grinding surface of the grindstone occurs, truing by the electric discharge machining can be immediately performed. It is possible to always maintain the shape of the grindstone with extremely high precision. Therefore, the grindstone is always clogged and maintained in a state of high shape accuracy, and processing with extremely small surface roughness and high shape accuracy can be performed.

According to a second aspect of the present invention, there is provided the electric discharge machine according to the first aspect, further comprising a wire electrode running along a wire guide supported opposite to the grindstone. In this grinding machine, since a wire electrode is used in the electric discharge machine, machining errors due to consumption of the machining electrode are avoided, and it is possible to truing the grindstone with high accuracy.

According to a third aspect of the present invention, in the grinding apparatus according to the first or second aspect, the first processing liquid for supplying an electrolytic solution to a position where the electrode of the dressing means faces the grinding wheel. A supply means, and a second machining liquid supply means for supplying an insulating machining liquid to a position where the discharge electrode of the electric discharge machining apparatus faces the grinding wheel.

In this grinding machine, the first working fluid supply means or the second working fluid supply means is selected and operated to supply an electrolytic solution or an insulating working fluid while grinding the workpiece. Thus, dressing or truing can be performed efficiently.

According to a fourth aspect of the present invention, there is provided an electrolysis electrode in which a voltage is applied between the grinding wheel and the grinding wheel which is in close proximity to the rotationally driven grinding wheel, and a discharge which causes a discharge between the electrode and the electrode. An electrode is disposed, and the rotating grindstone is brought into contact with a workpiece to perform grinding, and at the same time, an electrolytic solution is supplied between the ground surface of the grindstone and the electrode for electrolysis to sharpen by electrolytic action. Performing the grinding by bringing the grinding wheel into contact with the workpiece, and simultaneously performing a shape change by electrical discharge machining by generating a discharge between the ground surface of the grinding wheel and the discharge electrode. To perform a grinding process on a workpiece by switching to a grinding method.

In this grinding method, it is possible to arbitrarily switch between a step of performing dressing by electrolytic action while grinding the workpiece and a step of performing truing by electric discharge machining while performing grinding.
Dressing or truing can be performed according to the state of the grindstone during the grinding process. That is, dressing by electrolytic action can be performed when clogging of the grinding surface of the grindstone progresses, and truing by electric discharge machining can be performed when the shape of the grindstone progresses. Therefore, even if the degree of clogging or shape change varies depending on the material of the workpiece or the like, it is possible to easily cope with the variation, and it is possible to perform grinding while always maintaining the grindstone in a good state.

According to a fifth aspect of the present invention, in the grinding apparatus according to the first or second aspect, the first machining fluid supplies a machining fluid to a position where the electrode of the dressing means faces the grinding wheel. A supply means, and a second machining fluid supply means for supplying a machining fluid to a position where the discharge electrode of the electric discharge machining device is opposed to the grindstone, wherein the first machining fluid supply means and the second machining fluid are provided. The supply means supplies the same processing liquid.

In this grinding apparatus, the same machining liquid is supplied between the electrode of the dressing means and the grindstone and between the discharge electrode of the electric discharge machine and the grindstone. There is no problem that the working fluid supplied to the nozzle is mixed, and by appropriately selecting the working fluid, both dressing by electrolytic action and truing by electric discharge machining can be performed simultaneously with grinding.

According to a sixth aspect of the present invention, there is provided an electrolysis electrode in which a voltage is applied between the rotating stone and the grinding wheel, and a discharge between the electrode and the electrode. An electrode is disposed, and a working fluid having a volume resistivity of 0.1 kΩm or more and 10 kΩmu or less is supplied between the grinding surface of the grinding wheel and the electrode for electrolysis, and between the grinding surface of the grinding wheel and the discharge electrode. Contacting the rotating grindstone with the workpiece to perform grinding; applying a voltage between the electrolytic electrode and the grindstone to perform dressing by electrolytic action; It is an object of the present invention to provide a grinding method for simultaneously performing a step of reshaping the grindstone by an electric discharge between an electrode and the grindstone.

In this grinding method, the same working fluid is supplied between the grinding surface of the grinding wheel and the electrode for electrolysis, and between the grinding surface of the grinding wheel and the discharge electrode. As described above, a material having a rate of 0.1 kΩm or more and 10 kΩm or less is used. Further, it is desirable to use one having a value of 0.5 kΩm or more and 1.5 kΩm or less. By using a machining fluid having a volume resistivity within the above range, dressing by electrolytic action can be performed by being interposed between the grinding wheel and the electrode for electrolysis, or by interposing between the grinding wheel and the discharge electrode. Electric discharge can be caused, and dressing by electrolytic action and truing by electric discharge machining can be performed simultaneously. That is, grinding can be performed while always performing dressing and truing of the grindstone. Using a grindstone having a small abrasive particle diameter, grinding with extremely small surface roughness and high shape accuracy can be performed.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a grinding apparatus according to an embodiment of the invention described in claim 1, claim 2, claim 3, or claim 5. The grinding apparatus includes a grindstone 2 for performing grinding by contacting a workpiece (workpiece) 3 while rotating, a spindle 1 for driving the grindstone 2 to rotate, and a grindstone support member for rotatably supporting the spindle 1. Fifteen
And a support 1a for fixing the whetstone 2 to the main shaft 1. An electrolytic dress electrode 5 for performing dressing by an electrolytic action by interposing a working liquid (electrolyte) between the grinding wheel 2 and a position close to and facing the peripheral surface of the grinding stone 2;
An electric discharge machining head 8 for generating a discharge between the grindstone 2 and reshaping by electric discharge machining; a grinding portion where the grindstone 2 and the work 3 face each other; and an electrolytic dress portion where the grindstone 2 and the electrolytic dress electrode 5 face each other. , A first nozzle 11, a second nozzle 12, and a third nozzle 1 for jetting and supplying a machining liquid to an electric discharge machining unit where the grindstone 2 and the electric discharge machining head 8 are opposed to each other.
3 is provided.

The grinding wheel 2 is driven to rotate by rotation of the main shaft 1 supported by the grinding wheel support member 15, and a moving mechanism (not shown) attached to the grinding wheel support member 15.
As a result, the main shaft 1 moves in the axial direction and the vertical direction while rotating. The grindstone 2 has conductivity for performing dressing or the like during grinding. In this embodiment, a metal bond grindstone is used in which a bond material as a base material of the grindstone 2 is made of a metal mainly composed of iron or copper, and abrasive grains are solidified by the bond material. This bond material contains abrasive grains and has a role of holding the abrasive grains exposed on the surface of the grindstone 2. The abrasive grains may be either conductive or non-conductive material, but in this example, non-conductive one is used.

The work 3 is fixedly supported by a table 4 installed on a support table 14, and is moved by a moving mechanism of the table 4 in the direction of arrow A (left-right direction) shown in the drawing. Then, the surface of the work 3 can be processed into a free shape by moving the table 4 and the above-mentioned grindstone support member 15 to control the contact point of the work 3 with the grindstone to an arbitrary position. This work 3 may be either a conductive material or a non-conductive material,
It is desirable to set an appropriate working fluid or the like according to the material of the work.

The electrolytic dress electrode 5 is connected to a power source 6 for electrolysis by a wiring 7a, and the other wiring 7b
Is connected to the main shaft 1 by a brush (not shown).
A constant voltage or a pulse voltage having a special pattern is applied from the electrolysis power supply 6 through the wiring 7, and the machining liquid supplied from the second nozzle 12 is interposed between the electrode 5 and the grindstone 2. It is designed to work. In this example, the voltage applied from the power supply 6 for electrolysis is 90 V, and a current having a peak value of 10 A is applied for 2 μs to generate 2 μm.
It is controlled so as to flow with a pulse system that pauses. In this case, the polarity is positive on the side of the rotating spindle 1 of the grindstone 2 and negative on the side of the electrolytic dress electrode 5. The length of the electrolytic dress electrode 5 (the length in the circumferential direction of the grindstone) is about 1/5 to 1/4 of the entire circumference of the grindstone, and the width is about the same as the grindstone width or 0.5.
It is set to be about mm wide. The material of the electrolytic dress electrode 5 is copper having good conductivity, and the distance between the electrode 5 and the grindstone 2 is set to about 0.15 to 0.3 mm.

The electric discharge machining head 8 is connected to a power supply 9 for electric discharge machining by a wiring 10a, and another wiring 10b from the power supply 9 for electric discharge machining is a brush (not shown) connected to the main shaft 1.
Connected by Then, a voltage is applied from a power supply 9 for electric discharge machining to generate electric discharge between the electric discharge machining head 8 and the grindstone 2. In this case, the polarity of the electric discharge machining head 8 is minus and the polarity of the main shaft 1 is plus. Discharge generation conditions are as follows: voltage 200V, capacitor capacity 100p
F, the charge resistance is set to 1.1 kΩ, and discharge is generated by a capacitor charge / discharge method. The distance between the electric discharge machining head 8 and the grindstone 2 is set to about 2 μm in order to generate an appropriate electric discharge.

FIG. 2 shows the electric discharge machining head 8 in detail.
The electric discharge machining head 8 has a traveling mechanism for wires arranged on a base plate 81 made of ceramic, and uses a traveling electrode wire 82 as an electrode for electric discharge machining. This electrode wire 82 has a diameter of 0.1 mm.
The material is brass. As shown in FIG. 2A, a delivery bobbin 8 for an electrode wire 82 is provided on a base plate 81.
3. The take-up bobbin 91, the brake roller 84, the rotating rollers 85, 86, 87 and the like are rotatably supported, and are prepared in a state in which a necessary wire amount is wound on the delivery bobbin 83 in advance. There are three grooves around the brake roller 84, and the electrode wire 82 from the delivery bobbin 83 and the electrode wire from the rotating rollers 85 and 86 are received in separate grooves, so that the running electrode wire is entangled. Care is taken not to have it. The brake roller 84 is rotatable around the axis, but the shaft has a mechanism (not shown) that suppresses rotation by friction around the shaft by friction.
Therefore, the tension is applied to the wire in a direction opposite to the running direction. This prevents loosening of the wire and avoids troubles such as the wire coming off from the wire guide 89 described later.

Brake roller 84 and rotating roller-8
A wire guide 89 is attached to the downstream side of 7 so as to protrude from the base plate 81, and the wire guide 89 is arranged so as to face the grindstone 2. The wire guide 89 is screwed to the tip of the guide arm 88 and does not rotate. A guide groove of approximately the same width as the diameter of the wire is cut around the wire guide 89,
The wire runs along the guide groove. This guide groove has a depth of about half the wire diameter,
The electrode wire 8 having a semicircular cross section and being guided
The half of 2 is supported so as to protrude outside the wire guide. Then, the portion of the electrode wire 8 exposed to the outside is
A discharge is generated between the grinding wheel 2 and the grinding wheel 2.
The winding bobbin 91 is located behind the base plate 81 and is driven to rotate by a motor (not shown). The winding bobbin 91 plays a role of winding the electrode wire 82 passing through the wire guide 89 and the rotating roller 90.

The electric discharge machining head 8 having such a mechanism
Then, the electrode wire 82 ejected from the delivery bobbin 83
First, the vehicle travels in the form of reciprocating rotating rollers 85 and 86 that can be rotated around an axis by changing the direction with a brake roller 84. Electrode wire 82 coming out of brake roller 84
Then, the direction is changed by the rotating roller 87 and sent to the wire guide 89. When traveling along the wire guide 89, a voltage is applied between the electrode wire 82 and the grindstone 2 by a voltage applied from the electric power source 9 for electric discharge machining, and electric discharge machining of the grindstone 2 is performed. Then, the electrode wire 82 that has passed the wire guide 89 changes its direction via a rotating roller 90 and is sent to a winding bobbin 91.

With the mechanism described above, the electrode wire 82 runs along the periphery of the wire guide 89. However, it is necessary to always replace the wire consumed by the electric discharge machining with a new part by running. Thus, the gap with the grindstone 2 is controlled to be constant. It is appropriate that the wire 82 travels at a speed of about several tens of mm per minute.

As shown in FIG. 2B, the electric discharge machining head 8 is fixedly supported on a vertical moving table 93 by a mounting shaft 92, and the vertical moving table 93 is attached to an L-shaped horizontal moving table 94 in the figure. Are supported so as to be movable in the direction of arrow B shown in FIG. The horizontal moving table 94 is supported by a projection 15a provided on the grindstone support member 15 so as to be movable in the direction of arrow C shown in the figure. By controlling these tables, it is possible to control the movement of the electric discharge machining head 8 in two axes in the vertical or horizontal direction with respect to the rotation of the grindstone 2. Thus, the distance between the grindstone 2 and the electric discharge machining head 8 can be controlled to a distance at which electric discharge machining can be performed, and at the same time, can be moved over the width of the grindstone to shape the grindstone into an arbitrary shape.

Next, the working fluid used in this grinding machine will be described. The supply of the machining fluid from the first nozzle 11 between the grindstone 2 and the work 3 is performed by lubricating the ground surface.
The supply of the machining fluid from the second nozzle 12 is for causing an electric current to flow in the electrolytic dress portion to cause an electrolytic reaction, and the supply of the machining fluid from the third nozzle 13 is for cooling and cleaning. This is for generating electric discharge by insulating the electric discharge machining part. In general, it is considered ideal that the machining fluid to be supplied to these three locations, particularly the electric field dressing section and the electric discharge machining section, should be selected separately for each purpose. Is very high, from several thousand to several tens of thousands of rpm, so that the respective working fluids are mixed, and it is very difficult to use different working fluids. Therefore, here, the same processing fluid is supplied, and a processing fluid that satisfies the function of each unit is set.

As the working fluid used, a commercially available electrolytic solution for electrolytic dressing is used after further diluting it to a concentration generally used. This is because the insulation required for electric discharge machining cannot be obtained with the concentration of the generally used electrolytic dressing solution. Actually, the volume resistivity of the working fluid is 100Ωm
Thus, electric discharge can be generated, and electric discharge machining can be stably performed at about 1 kΩm or more. And, as the volume resistivity further increases, the EDM becomes better,
This time, it becomes difficult to obtain the current required for electrolysis. Therefore,
The range of the volume resistivity of the electrolyte is 0.1 kΩm or more and 1
0 kΩm or less, preferably 0.5 kΩm or more and 1.5 k
Ωm or less is suitable.

Next, a description will be given of a grinding method according to an embodiment of the present invention, which is an operation of such a grinding apparatus. When the apparatus is started, the movement of the grindstone 2 relative to the work 3 is controlled by a moving mechanism (not shown), and the abrasive grains of the grindstone 2 scrape the surface of the work 3 while rubbing the surface. It is ground to the shape and dimensions. A voltage is applied between the electrolytic dress electrode 5 and the grindstone 2 from the power source for electrolysis 6 before the grindstone 2 is clogged by the grinding process. As a result, an electrolytic action occurs between the electrolytic dress electrode 5 and the grindstone 2, grinding dust clogged between the abrasive grains is removed by the electrolytic action, and dressing (dressing) of the grindstone 2 is performed. At this time, if the grinding waste is conductive, the surface of the grinding waste is directly eluted, and the grinding waste is removed from the abrasive grains. On the other hand, when the grinding chips are non-conductive, the gas generated on the surface of the electrolytic dress electrode 5 can remove the grinding chips by the expansion pressure of the bubbles. This makes it possible to remove grinding debris without interrupting the grinding process,
It is possible to prevent an increase in the grinding resistance of the grindstone 2 and maintain good cutting properties.

In performing the dressing, a voltage is applied between the electric discharge machining head 8 and the grindstone 2 from the electric discharge machining power supply 9. At this time, the electric discharge machining head 8 is controlled to move vertically or horizontally with respect to the grindstone 2 by the moving mechanism shown in FIG. As a result, electric discharge is generated between the electric discharge machining head 8 and the grindstone 2, and the ground surface of the grindstone 2 is reshaped (truing) by electric discharge machining.

In such a grinding apparatus, grinding can be performed while simultaneously dressing and truing the grindstone, and there is no need to interrupt the grinding to perform these steps. For this reason, a grindstone having a small abrasive particle diameter can be used without lowering the grinding efficiency, and cutting with extremely small surface roughness and high shape accuracy can be performed.

Next, a grinding apparatus according to an embodiment of the present invention as defined in claim 1, 2 or 3, and the operation of the grinding apparatus, which is an embodiment of the invention according to claim 4, A grinding method according to an embodiment will be described. This grinding apparatus has substantially the same configuration as the grinding apparatus shown in FIG. 1, except that the step of performing the grinding of the workpiece and simultaneously dressing the grindstone with the electrolytic dress electrode and the step of performing the grinding of the workpiece and simultaneously discharging the workpiece are performed. The step of truing the grindstone by machining is set to be arbitrarily switched. At this time, the processing liquid supplied from each nozzle is also switched, and during the execution of the dressing, a normal electrolytic solution is ejected from the second nozzle between the electrode for electrolysis and the grindstone,
When switching to electric discharge machining, an insulating liquid such as pure water is ejected from the third nozzle between the electric discharge electrode and the grindstone. The other configuration of this grinding apparatus is the same as that of the grinding apparatus shown in FIG.

In such a grinding apparatus, the step of performing dressing while grinding the workpiece and the step of performing truing while performing grinding can be arbitrarily switched. Dressing or truing can be performed depending on the state of the change. For this reason, by selecting a working fluid suitable for each step, a higher dressing or truing effect can be obtained, and grinding can be performed while maintaining a good state of the grindstone.

[0041]

As described above, in the grinding apparatus or the grinding method according to the present invention, the dressing can be quickly performed according to the degree of clogging of the grinding wheel without interrupting the grinding. Further, truing can be performed according to a change in the shape of the grinding surface of the grindstone. For this reason, it is possible to prevent clogging of the grindstone and to maintain the shape of the grindstone with high precision, thereby performing grinding with extremely small surface roughness and high form precision.
In addition, the machining fluid supplied to the position facing the grindstone and the dressing means and the machining fluid supplied to the position facing the grindstone and the electric discharge machine are the same machining fluid having an appropriate volume resistivity, so that the grinding process is performed. The dressing and truing of the grindstone can be performed simultaneously. For this reason, highly accurate and highly efficient grinding can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a grinding apparatus according to an embodiment of the present invention.

FIG. 2 is a front view and a side view showing details of an electric discharge machining head used in the grinding machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spindle 2 Grinding wheel 3 Work 4 Table 5 Electrolysis dress electrode 6 Electrolysis power supply 7 Wiring 8 Electric discharge machining head 9 Electric discharge machining power supply 10 Wiring 11 First nozzle 12 Second nozzle 13 Third nozzle 15 Grindstone support member 81 Base plate 82 electrode wire 83 sending-out bobbin 84 brake roller 85, 86, 87, 90 rotating roller 88 guide arm 89 wire guide 91 winding bobbin 92 mounting shaft 93 vertical moving table 94 horizontal moving table

Claims (6)

[Claims] 1. A conductive grindstone that contacts a workpiece in a rotationally driven state and performs a grinding process; and a grindstone supporting means that supports the grindstone relatively movably with respect to the workpiece. A dressing means for providing an electrode opposing the grinding wheel in close proximity to the grinding wheel, interposing a working fluid between the electrode and the grinding wheel, performing dressing by electrolytic action, and being arranged close to the grinding wheel, And a discharge machining device supported so that the relative position can be adjusted. 2. The grinding apparatus according to claim 1, wherein the electric discharge machining apparatus has a wire electrode running along a wire guide supported opposite to the grindstone. 3. A first machining liquid supply means for supplying an electrolytic solution to a position where an electrode of the dressing means faces the grindstone, and an insulating process at a position where a discharge electrode of the electric discharge machining apparatus faces the grindstone. The grinding apparatus according to claim 1, further comprising a second processing liquid supply unit configured to supply a liquid. 4. In close proximity to a rotationally driven grindstone,
An electrode for electrolysis to which a voltage is applied between the grinding stone and a discharge electrode for generating a discharge between the grinding stone and the grinding wheel are arranged, and the rotating grinding wheel is brought into contact with a workpiece to perform grinding. At the same time, a step of supplying an electrolytic solution between the grinding surface of the grindstone and the electrode for electrolysis to perform dressing by electrolytic action, and performing the grinding by bringing the grindstone into contact with a workpiece and simultaneously grinding the grindstone. A step of causing a discharge between the ground surface and the discharge electrode to reshape by electric discharge machining,
Characterized in that the workpiece is ground by arbitrarily switching the processing. 5. A first machining fluid supply means for supplying a machining fluid to a position where an electrode of the dressing means faces the grindstone, and a machining fluid at a position where a discharge electrode of the electric discharge machining apparatus faces the grindstone. 2. A second processing liquid supply unit that supplies the same processing liquid, wherein the first processing liquid supply unit and the second processing liquid supply unit supply the same processing liquid. 3. Alternatively, the grinding apparatus according to claim 2. 6. In the vicinity of a grindstone driven in rotation,
An electrode for electrolysis to which a voltage is applied between the grindstone and a discharge electrode for generating a discharge between the grindstone and the electrode for electrolysis are disposed, between the grinding surface of the grindstone and the electrode for electrolysis, and the grindstone. Between the ground surface and the discharge electrode has a volume resistivity of 0.1 k
Supplying a machining fluid of not less than Ωm and not more than 10 kΩm to perform grinding by bringing the rotating grindstone into contact with a workpiece, and applying a voltage between the electrode for electrolysis and the grindstone to perform electrolysis. A grinding method, wherein a step of performing dressing by action and a step of reshaping the grindstone by electric discharge between the discharge electrode and the grindstone are performed simultaneously.