JPH10225865A - Grinding device using metal bond grinding wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding device using a power source of a relatively small capacity in which ELID grinding can be performed in accordance with an abrasion condition of the grinding wheel even where the grinding wheel is of a wide width. SOLUTION: A device is provided with a metal bond grinding wheel 2, a support rotation means rotatably supporting the grinding wheel 2 for rotating it in a specified direction, a dressing electrode 11 provided to face a grinding action surface of the grinding wheel 2, a power source 6 of which one electrode is connected to the grinding wheel 2, with the other electrode connected to the dressing electrode 11, for applying a voltage between the grinding wheel 2 and the dressing electrode 11, and a grinding liquid supply means to supply conductive grinding liquid to between the grinding wheel 2 and the dressing electrode 11. The dressing electrode 11 i formed of plural electrode bodies 11a provided in parallel along a rotation shaft 3 of the grinding wheel 2, and an insulation body 11b is provided between the adjacent electrode bodies 11a. A changing means 12 is provided to change the electrode bodies 11a and the power source 6 to be connected in order. The capacity of the power source 6 can thus be set small, thereby the whole body of the grinding device can be compact.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grinding apparatus using a metal bond whetstone having high hardness, and more particularly, to a grinding apparatus for dressing a whetstone by an electrolytic action while performing a grinding process.

[0002]

2. Description of the Related Art It has been known that high-strength metal-bonded superabrasive grindstones such as cast iron fiber-bonded diamond grindstones are suitable for ultraprecision machining of hard-hard materials such as ceramics. Electrolytic in-process dressing (hereinafter referred to as “ELID”) grinding has been developed as a highly efficient grinding method using this high-strength metal-bonded superabrasive grindstone, and has recently attracted attention.

[0003] The high-strength metal-bonded superabrasive grindstone has high strength and is suitable for ultra-precision processing of the hard-hard and difficult-to-machine material, but because of its high strength, its dressing is not easy. In the mechanical dressing using a rotary diamond or the like, the dressing operation not only requires a long time, but also the rotary diamond itself is severely worn, and the operation is extremely difficult.

[0004] The ELID grinding method has been developed. The ELID grinding method is simply a method of dressing a grindstone by an electrolytic process (in-process) while performing a grinding process.

FIGS. 5 and 6 show an apparatus as a specific example for carrying out the ELID grinding method. As shown in FIG. 1, the ELID grinding apparatus includes a metal bond grindstone 2 supported by a support rotating means (not shown) and rotating in a fixed direction, and a blade 5 rotatably supporting a workpiece W.
An ELID grinding method is applied to a centerless grinding device provided with an adjustment wheel 4 that rotates in the same direction as the metal bond grinding wheel 2 and presses the workpiece W against the metal bond grinding wheel 2. A dressing electrode 1 provided facing the grinding action surface of the bond whetstone 2;
A conductive grinding liquid is supplied between the metal bond grinding wheel 2 and the dressing electrode 1, and a power source 6 having an anode connected to the rotating shaft 3 of the metal bond grinding wheel 2 and a cathode connected to the dressing electrode 1. And a grinding fluid supply means 7.

The metal bond grindstone (hereinafter simply referred to as “grindstone”) 2 holds superabrasive grains such as diamond and CBN with a conductive binder (metal bond) such as cast iron. When a predetermined voltage is applied between the rotating shaft 3 of the grindstone 2 and the dressing electrode 1, the surface of the metal bond grindstone becomes an anode due to the conductivity of the metal bond, and the dressing electrode 1 becomes a cathode.

When a conductive grinding liquid (preferably a weakly conductive grinding liquid) is supplied thereto from the grinding liquid supply means 17, for example, when the metal bond is cast iron, the surface of the grinding wheel 2 is electrolyzed. Iron ions (Fe ²⁺ ) elute from the metal bond portion, and the abrasive grains are exposed on the surface of the grindstone 2 to perform dressing.

A certain percentage of the iron ions (Fe ²⁺ ) change into iron hydroxide, and finally change into hard iron oxide and adhere to the surface of the grindstone 2. 2
Form on the surface. Since iron oxide is electrically insulating, elution of iron ions (Fe ²⁺ ) due to electrolysis is suppressed when the iron oxide film is sufficiently formed.

Next, if grinding is performed subsequently in this state, the abrasive grains are worn and the iron oxide film starts to be released from the surface of the grinding wheel 2 due to friction with the workpiece W. The iron oxide film covering the surface becomes insufficient and the conductivity is restored again, and the above-described series of processes is repeated.

In such an ELID grinding apparatus, when the grinding fluid is supplied to the grindstone 2, the air flowing along the outer periphery of the grindstone 2 flows between the grindstone 2 and the dressing electrode 1, and the grinding fluid is removed. A cover for covering the dressing electrode 1 and the grinding fluid supply means 7 in order to prevent inconveniences such as uneven supply of the fluid and a so-called grinding fluid separation state in which the grinding fluid is scattered by centrifugal force. 8 (indicated by a two-dot chain line in FIGS. 5 and 6). The gap between the cover 8 and the grindstone 2 is set to be very small.
The inside of the cover 8 is in an airtight state.

As described above, the ELID grinding method is capable of performing the grinding process while performing dressing as needed. The grinding process can be performed with extremely high efficiency, and the dressing is performed electrochemically. Compared to a conventional mechanical dressing using a rotary diamond or the like, the resistance is smaller and the whole device can be made compact.

[0012]

However, the conventional EL
Since the ID grinding device uses a single dressing electrode 1 having a width corresponding to the entire width of the grinding wheel 2, for example, when a wide grinding wheel 2 is used as in a centerless grinding device, the ID dressing device is adapted. It was necessary to prepare a power supply 6 having a large capacity.

While the capacity of the power source 6 is kept constant,
When the width of the dressing electrode 1 is increased in accordance with the width of the electrode, the surface area of the dressing electrode 1 increases, the current density per unit area of the dressing electrode 1 decreases, and the electrolytic action is weakened. Causes the dressing of the grinding wheel 2 to be delayed, causing the grinding wheel 2 to be clogged. Therefore, in order to perform ELID grinding without hindrance, the capacity of the power source 6 must be increased in accordance with the width of the grindstone 2 so that the dressing is performed at a speed that does not cause clogging of the grindstone 2.

In order to solve this problem, as shown in FIG. 7, the dressing electrode 1 is made narrower than the width of the grindstone 2.
This may be configured to traverse along the rotation axis 3 of the grindstone 2 in the direction indicated by the arrow, and the capacity of the power source 6 may be reduced as much as possible. In addition, since the cover 8 that covers the dressing electrode 1 and the grinding fluid supply means 7 cannot be provided, the above-described problem of grinding fluid separation cannot be avoided, and stable ELID grinding cannot be performed. is there.

When the dressing electrode 1 is traversed (reciprocated), the time at which the dressing electrode 1 faces the grindstone 2 is different between both ends and the central portion of the grindstone 2. There is also a disadvantage that it becomes worse at both ends.

Further, for example, in the case of grinding by a through-feed method (a method in which a workpiece W is passed between the grindstone 2 and the adjustment wheel from one side to the other side and ground) using a centerless grinding apparatus, The work amount of the grinding action surface of the grindstone 2 is different in each part, and the wear state is different in each part. Therefore,
It is effective to dress according to the abrasion state of the grindstone 2, but if a single dressing electrode 1 is used, the dressing cannot be performed according to the abrasion state of the grindstone 2, so that it is efficient. There is also a problem that a dressing cannot be performed.

The present invention has been made in view of the above-mentioned circumstances, and is a grinding method capable of performing ELID grinding according to a worn state of a grinding wheel using a relatively small power supply even with a wide grinding wheel. The purpose is to provide the device.

[0018]

According to a first aspect of the present invention, there is provided a metal-bonded grindstone, and the metal-bonded grindstone is rotatably supported and rotated in a predetermined direction. The supporting rotation means to be performed, the dressing electrode provided to face the grinding action surface of the metal bond grindstone, and one electrode connected to the metal bond grindstone, and the other electrode connected to the dressing electrode. A grinding apparatus comprising: a power supply for applying a voltage between the metal bond grinding wheel and the dressing electrode; and a grinding fluid supply means for supplying a conductive grinding fluid between the metal bond grinding wheel and the dressing electrode. In the above, the dressing electrode is formed from a plurality of electrode bodies arranged side by side along the rotation axis of the metal bond grindstone, and formed by providing an insulator between the adjacent electrode bodies. Is characterized in that which is configured by providing a switching means for connecting sequentially switched and the said respective electrode body power.

According to this grinding apparatus, the plurality of electrode bodies are separated by the respective insulators and are electrically independent. Therefore, when the respective electrode bodies and the power source are sequentially switched and connected by the switching means, the plurality of electrode bodies are connected. A voltage is applied only between the switched electrode body and the metal bond grindstone, and the grinding surface of the metal bond grindstone corresponding to the electrode body is dressed by the electrolytic action. Thus, by switching by the switching means and sequentially connecting each electrode body and the power source, the grinding operation surface of the metal bond grindstone can be sequentially dressed, and finally, the entire grinding operation surface can be dressed.

As described above, instead of using a single electrode having a width corresponding to the entire width of the metal bond grindstone, a plurality of electrode bodies having a width smaller than the width of the metal bond grindstone are not rotated. Since they are juxtaposed along the axis, the power required for electrolysis at each electrode body can be minimized, and the capacity of the power supply can be reduced. As a result, the entire grinding device can be made compact.

According to a second aspect of the present invention, the switching means can arbitrarily set a connection time between the power supply and the electrode body and / or the electrode body to be connected.

With this configuration, the electrode body and the power supply are changed so that the connection state (time and number) between the electrode body and the power supply corresponding to the work amount of the grinding action surface of the grinding wheel is changed. Can be controlled, and thereby efficient dressing can be performed according to the wear state of the grinding action surface of the grindstone.

The invention according to claim 3 is characterized in that an adjacent surface of each electrode body of the dressing electrode is inclined with respect to a rotation axis of the metal bond grindstone.

If the adjacent surface of the electrode body is provided so as to be perpendicular to the rotation axis of the grindstone, when the insulator is thick, the electrolytic action does not reach the grinding action surface of the grindstone corresponding to the insulator.
The grinding action portion is not dressed at all, and as a result of being clogged, a step is generated on the processing surface of the workpiece and a disadvantage that a striped pattern is exhibited, but the adjacent surface of each electrode body is By tilting with respect to the rotation axis of the grindstone, the electrode body adjacent to the insulator overlaps and acts on the grinding surface corresponding to the insulator, so that the adjacent electrode body and the power supply are sequentially connected. By doing so, the dressing can be reliably performed also on the grinding action surface corresponding to the insulator. This can prevent the above-described inconvenience that a step is generated on the processed surface of the workpiece W and a striped pattern is formed.

According to a fourth aspect of the present invention, there is provided a grinding apparatus comprising: a blade rotatably supporting a workpiece; and an adjusting wheel for pressing the workpiece supported by the blade against the metal bond grindstone. In addition, a centerless grinding apparatus is provided. In a centerless grinding apparatus, a relatively wide grindstone is often used, and the above-described effects are remarkably exhibited, which is preferable.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a specific embodiment of the present invention will be described with reference to the accompanying drawings.

(First Embodiment) FIG. 1 is a perspective view schematically showing a grinding apparatus according to a first embodiment. As shown in FIG. The present invention is applied and embodied to the conventional ELID grinding apparatus shown in FIG. 6, and differs from the conventional ELID grinding apparatus in that the configuration of the dressing electrode 11 and the switching means 12 are provided. It has the same configuration as the grinding device. Therefore,
The same components as those of the conventional grinding device are denoted by the same reference numerals, and detailed description thereof will be omitted.

The dressing electrode 11 is provided so as to face the grinding surface of the grindstone 2. A plurality of (five in FIG. 1) electrode bodies 11 a are arranged side by side along the rotation axis 3 of the grindstone 2. And between the adjacent electrode bodies 11a.
It is configured by providing an insulator 11b. FIG.
1 is a plan view in the direction of arrow A in FIG. 1. As shown in FIG. 1, the electrode body 11 a is formed such that its adjacent surface is orthogonal to the rotation axis 3 of the grindstone 2.
In addition, various metals having conductivity, such as copper and stainless steel, can be applied to the electrode body 11a. Various insulators such as rubber can be used for the insulator 11b. However, since the insulator can be made as thin as possible, FR
It is preferable to use P (fiber reinforced plastic). F
If RP is used, the thickness of the insulator 11b can be kept within 0.1 mm.

The switching means 12 includes a relay unit 13
And the controller 14. The relay unit 1
Numeral 3 is provided with a plurality of relays corresponding to the respective electrode bodies 11a. One terminal of the relay is connected to the corresponding electrode body 11a, and the other terminal is connected to the power source 6a.
Connected to The controller 14 is composed of a programmable controller.
A signal for turning on an arbitrarily selected relay for an appropriate time can be output.

According to the grinding apparatus having the above configuration, the relay unit 1 receives a signal from the controller 14 and receives a signal from the controller 14.
3, the corresponding relay is turned ON, the electrode body 11a corresponding to the relay is connected to the cathode of the power source 6, and a predetermined voltage is applied between the electrode body 11a and the rotating shaft 3 of the grindstone 2. Applied. Then, the grinding action surface of the grindstone 2 corresponding to the electrode body 11a is dressed by the electrolytic action. Thus, by sequentially switching the electrode bodies 11a connected to the power supply 6 by the switching means 12,
The entire grinding surface of the grinding wheel 2 can be dressed.

As described above, in this apparatus, the dressing electrode 11 is not a single electrode having a width corresponding to the entire width of the grindstone 2, but a plurality of electrode bodies having a width smaller than the width of the grindstone 2. Since 11a are arranged side by side along the rotation axis of the grindstone 2, the power required for electrolysis can be reduced as much as possible, and the capacity of the power source 6 can be reduced. As a result, the entire grinding device can be made compact.

Further, the dressing electrode 11 is constituted by a plurality of electrode bodies 11a which are independently separated, and each electrode body 11a is switched by the controller 14 to be connected to the power source 6, so that the grinding wheel 2 is ground. The connection state between the electrode body 11a and the power source 6 corresponding to the work amount of the working surface can be varied, and efficient dressing according to the wear state of the grinding working surface of the grindstone 2 can be performed. Can be. For example, the controller 14 controls the number of times and / or the number of times of connection of the electrode body 11a corresponding to the grinding operation surface of the grindstone 2 having a relatively large amount of work with the power source 6 as compared with the other electrode bodies 11a. Then, the grinding action surface having a large amount of work can be dressed intensively. As a result, the grindstone 2 is not
Can be made substantially uniform over the entire surface.

(Second Embodiment) The grinding device according to the second embodiment is the same as the grinding device of the first embodiment.
As shown in FIG. 3, the adjacent surface of a is inclined with respect to the rotation axis 3 of the grindstone 2, and the other configuration is the first configuration.
It is the same as the grinding device of the embodiment.

In the above-described grinding apparatus according to the first embodiment, since the adjacent surface of the electrode body 11a is provided so as to be orthogonal to the rotating shaft 3 of the grinding wheel 2, the insulator 11b is provided.
When the thickness is thick, the electrolytic action does not reach the grinding action surface of the grindstone 2 corresponding to the insulator 11b, and the grinding action portion of the grindstone 2 is not dressed at all, and the clogging state is caused. Become. As a result, in the grinding action surface of the whetstone 2, the processing is favorably performed in a portion without clogging, the processing does not proceed in the clogged portion, and a step occurs on a processing surface of the workpiece W, and a stripe is formed. This is inconvenient because it takes on a pattern of shapes.

Therefore, in the grinding device according to the present embodiment, the adjacent surface of each electrode body 11a is inclined with respect to the rotation axis 3 of the grindstone 2. With this configuration, as shown in FIG. 3, of the grinding action surfaces of the grindstone 2,
As for the portion corresponding to the insulator 11b, the electrode members 11a adjacent to the left and right act to overlap, so that the adjacent electrode members 11b and the power supply 6 are connected in sequence to form the portion corresponding to the insulator 11b. Can be surely dressed. This can prevent the above-described inconvenience that a step is generated on the processed surface of the workpiece W and a striped pattern is formed.

In the centerless grinding apparatuses according to the first and second embodiments, a relatively wide grindstone 2 is often used, and the above-mentioned effects are remarkably exhibited.

Although the specific embodiment of the present invention has been described above, the grinding apparatus to which the present invention can be applied is not limited to this centerless grinding apparatus.
Naturally, it can be applied to a surface grinding device.

The switching means 12 is composed of the relay unit 13 and the controller 14. However, the switching means 12 is not limited to this. Any means can be used as long as each of the electrode bodies 11a and the power source 6 can be sequentially switched and connected. It may have a simple configuration.

Further, in FIG. 3, the adjacent surfaces of the electrode bodies 11a are inclined in the same direction. However, as shown in FIG. 4, they may be alternately inclined in opposite directions.
In this case, the same effect can be obtained.

[0040]

As described in detail above, claim 1 of the present invention
According to the present invention, the dressing electrode is formed from a plurality of electrode bodies arranged side by side along the rotation axis of the metal bond grindstone,
In addition, since an insulator is provided between adjacent electrode bodies and the switching means is configured to sequentially switch and connect each electrode body to a power source, the power required for electrolysis in each electrode body is minimized. And the capacity of the power supply can be made as small as possible. As a result, the entire grinding device can be made compact.

According to the second aspect of the present invention, the switching means can arbitrarily set the connection time between the power source and the electrode body and / or the electrode body to be connected. The connection between the electrode body and the power supply can be controlled so that the connection state (time, number) between the electrode body and the power supply corresponding to the work amount of the grinding action surface of the grinding wheel varies. Efficient dressing can be performed according to the wear state of the grinding surface.

According to the third aspect of the present invention, the surface adjacent to each electrode body of the dressing electrode is provided to be inclined with respect to the rotation axis of the grindstone, so that the grinding action surface corresponding to the insulator is provided. In addition, the electrode body adjacent to the insulator acts so as to overlap, and the dressing can also be reliably performed on the grinding surface corresponding to the insulator.

In the invention according to claim 4, the grinding device is a centerless grinding device. However, in the centerless grinding device, a relatively wide grindstone is often used, and the effect of the present invention as described above can be obtained. It can be significantly expressed.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing a grinding device according to a first embodiment.

FIG. 2 is a plan view showing the dressing electrode in the direction of arrow A in FIG. 1;

FIG. 3 is a plan view showing a dressing electrode according to a second embodiment.

FIG. 4 is a plan view showing a modification of the dress electrode according to the second embodiment.

FIG. 5 is a front view schematically showing a conventional ELID grinding device.

FIG. 6 is a perspective view schematically showing a conventional ELID grinding device.

FIG. 7 is a perspective view schematically showing a conventional ELID grinding device.

[Explanation of symbols]

 2 Metal bond whetstone 3 Rotary axis 6 Power supply 11 Dressing electrode 11a Electrode body 11b Insulator 12 Switching means 13 Relay unit 14 Controller

Claims (4)

[Claims] 1. A metal bond grindstone, supporting rotation means for rotatably supporting the metal bond grindstone, and rotating the metal bond grindstone in a predetermined direction, and a dressing device provided to face a grinding action surface of the metal bond grindstone. An electrode, one of the electrodes being connected to the metal bond grindstone, the other electrode being connected to the dress electrode, and a power source for applying a voltage between the metal bond grindstone and the dress electrode; In a grinding device comprising a grinding fluid supply means for supplying a conductive grinding fluid between a metal bond grindstone and a dress electrode, a plurality of the dress electrodes are arranged in parallel along a rotation axis of the metal bond grindstone. And a switching means for sequentially switching and connecting each of the electrode bodies and the power supply, while providing an insulator between the adjacent electrode bodies. A grinding device using a metal bond grinding wheel, characterized in that the grinding device is configured as follows. 2. The grinding apparatus according to claim 1, wherein the switching means can arbitrarily set a connection time between the power supply and the electrode body and / or the electrode body to be connected. 3. The grinding using the metal bond grinding wheel according to claim 1, wherein an adjacent surface of each electrode body of the dress electrode is inclined with respect to a rotation axis of the metal bond grinding wheel. apparatus. 4. The centerless grinding apparatus according to claim 1, wherein the grinding apparatus further includes a blade rotatably supporting the workpiece, and an adjusting wheel for pressing the workpiece supported by the blade against the metal bond grindstone. , Claim 1 or 2 or 3
A grinding device using the metal bond whetstone described in the above.