JPH071333A - Electrolytic dressing controlling method and device - Google Patents

Abstract

PURPOSE:To provide an electrolytic dressing method and device capable of performing stable and efficient ELID grinding while restraining electric current from increasing too much and stably forming films. CONSTITUTION:In electrolytic dressing grinding by which a workpiece 1 is ground while dressing with voltage applied between a grinding wheel 2 and an electrode 3 from a power source 5 and power supply body 6 while letting conductive liquid flow between the grinding wheel 2 and the electrode 3 from a nozzle 4, the electric current or voltage is detected by a position controlling device 20, and the distance between the grinding wheel 2 and electrode 3 is adjusted by an electrode shifting device 10 so as to keep this detected value within a predetermined range.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method and apparatus for controlling electrolytic dressing.

[0002]

2. Description of the Related Art A conductive grindstone such as a cast iron fiber-bonded diamond grindstone is used, and a method and apparatus for electrolytic dressing of a conductive grindstone, in which a voltage is applied to the grindstone and the grindstone is dressed electrolytically, by the same applicant as the present application. Kohei
It has been disclosed in Japanese Patent Application No. 1-188266 (Japanese Patent Application No. 63-12305) and has succeeded in mirror-polishing a semiconductor material such as silicon, which is an electronic material. Furthermore, an electrolytic in-process dressing grinding method (Electrolytic Inproc
ess Dressing: A method and a device called “ELID grinding method” have been developed and announced by the applicant of the present application (RIKEN Symbodium “Latest Technology Trend of Mirror Grinding”, held on March 5, 1991). This ELID grinding method uses a grindstone having a contact surface with the workpiece, an electrode facing the grindstone with a gap, and a nozzle for flowing a conductive liquid between the grindstone and the electrode.
Using a device consisting of a power supply and a power supply that applies a voltage between the grindstone and the electrode, while applying a conductive liquid between the grindstone and the electrode, a voltage is applied between the grindstone and the electrode, It is dressed by electrolysis. Figure 4 shows the mechanism of dressing by this ELID grinding method. At the start (A) of dressing of the grindstone, a relatively large current (5 to 10 A) flows with a small electric resistance between the grindstone and the electrode. Thereby, the metal portion (bond) on the surface of the grindstone is dissolved by the electrolytic effect, and the non-conductive diamond abrasive grains are projected. Further, when electricity is continued, an insulating coating mainly composed of iron oxide (Fe ₂ O ₃ ) is formed on the surface of the grindstone, and the electric resistance of the grindstone increases. As a result, the current is reduced, the dissolution of the bond is reduced, and the protrusion of the abrasive grains (grinding of the grindstone) is substantially completed (B). When grinding is started in this state (C), the coating particles release grinding debris, and the diamond abrasive grains wear as the work is ground. When the grinding is further continued (D), the insulating coating on the surface of the grindstone is removed by abrasion, the electric resistance of the grindstone is lowered, the current between the grindstone and the electrode is increased, the melting of the bond is increased, and the protrusion of the abrasive grains (grinding stone Is reopened. Therefore, during grinding by the ELID grinding method, excessive dissolution of the bond is suppressed by forming / removing the coating as in (B) to (D), and the protrusion of the abrasive grains (sharpening of the grindstone) is automatically adjusted. It (B) ~
The cycle shown in (D) is hereinafter called an ELID cycle.
In the above-mentioned ELID grinding method, even if the abrasive grains are made fine, the abrasive stone will not be clogged due to the sharpening of the stone by the ELID cycle, so if the abrasive grains are made fine, an extremely excellent processed surface such as a mirror surface can be obtained by grinding. You can Therefore,
The ELID grinding method can maintain the sharpness of the grindstone from high-efficiency grinding to specular grinding, and is expected to be applied to die machining that uses grinding frequently.

[0003]

The current (I) and voltage (V) in the above-mentioned ELID grinding become substantially constant after a certain time as shown schematically in FIG. In other words, the projection of abrasive grains and the formation / removal of the coating film are determined by the balance between the processing conditions and the electrolytic conditions in the ELID cycle, which keeps the grinding efficiency and the surface roughness of the ground surface almost constant. However, in the conventional ELID grinding, the position of the electrode is held at a constant position during grinding, and therefore, there is a problem that the distance between the grindstone and the electrode is constant. Therefore, in order to improve the grinding efficiency, it is necessary for a skilled operator to narrow the gap between the grindstone and the electrode to increase the current of the electrolytic dressing and promote the protrusion of the abrasive grains. However, this adjustment is delicate, and if the gap is made too narrow, the current will become too high, and the coating will hardly be formed, and the stability of ELID grinding will be deteriorated. Therefore, in the past, the grinding efficiency was sacrificed to some extent and the electrode was held at an appropriate position where stable ELID grinding was obtained. The present invention was created to solve such problems. That is, the object of the present invention is to
An object of the present invention is to provide a control method and device for electrolytic dressing that can perform ELID grinding with high efficiency and stability.

[0004]

According to the present invention, while a conductive liquid is allowed to flow between a grindstone and an electrode, a voltage is applied between the grindstone and the electrode, and the grindstone is electrolytically dressed while the workpiece is dressed. In electrolytic dressing grinding to grind, the current or voltage between the electrode and the grindstone is detected, and the distance between the grindstone and the electrode is adjusted so that the detected value is within a set range. Provided. Furthermore, according to the present invention, a grindstone having a contact surface with the workpiece, an electrode facing the grindstone with a gap, a nozzle for flowing a conductive liquid between the grindstone and the electrode, and between the grindstone and the electrode. In the electrolytic dressing grinding for grinding the work while dressing the grindstone by electrolysis, an electrode moving device that moves the electrode to change the distance between the grindstone and the electrode, and an electrode. A position control device that detects a current or a voltage between the grindstones and outputs a movement signal to the electrode moving device so that the detected value falls within a set range is provided, whereby the detected value falls within the set range. There is provided an electrolytic dressing control device characterized by adjusting a distance between the grindstone and the electrode. According to a preferred embodiment of the present invention, the position control device is provided between the electrode and the power supply and the power source, and increases the distance between the grindstone and the electrode when the detected current value becomes larger than the set range. A movement signal is output to the electrode moving device, and when the current value becomes smaller than the set range, the movement signal is output to the electrode moving device so as to reduce the distance between the grindstone and the electrode. Further, the position control device is provided between the electrode and the power supply body and the power supply, and outputs a movement signal to the electrode moving device so as to reduce the distance between the grindstone and the electrode when the detected voltage value exceeds the set range. However, it is preferable to output a movement signal to the electrode moving device so as to increase the distance between the grindstone and the electrode when the voltage value becomes smaller than the set range. Further, according to a preferred embodiment of the present invention, the electrode moving device comprises
A support member that slidably supports the electrode from a position in close contact with the grindstone to a position spaced apart from it, a taper member slidably supported in a direction orthogonal to the sliding direction of the support member, and the taper member And a drive device for moving according to the output of the position control device, a cylindrical roller is rotatably pivotally attached to the support member, and the taper member engages with an outer peripheral surface of the roller. It has a tapered surface. It is preferable that the drive device includes an elongated male screw member that is rotationally driven by a pulse motor, and the male screw member is screwed with a female screw member provided on the taper member.

[0005]

According to the above method and apparatus of the present invention, the interval between the grindstone and the electrode is automatically adjusted so that the current or voltage between the electrode and the grindstone falls within the set range, so that the grinding efficiency is improved. For example, even if the current setting range is increased, the current is automatically controlled within the setting range. Therefore, the current does not become too high, the formation of the film is performed stably,
ELID grinding can be performed stably.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. In addition, in each figure, the same parts are denoted by the same reference numerals. FIG. 1 is an overall configuration diagram of an electrolytic dressing control device according to the present invention. In this figure, an electrolytic dressing apparatus includes a grindstone 2 having a contact surface with a work 1 and an electrode 3 facing the grindstone with a gap.
And a nozzle 4 for flowing a conductive liquid between the grindstone 2 and the electrode 3.
And a power supply 5 that applies a voltage between the grindstone 2 and the electrode 3, and a conductive liquid flows between the grindstone 2 and the electrode 3, while the conductive liquid flows between the grindstone 2 and the electrode 3. Apply voltage,
The work 1 is ground while dressing the grindstone 2 electrolytically. This structure is similar to the conventional ELID grinding machine.

The electrolytic dressing control device according to the present invention further detects the current or voltage between the electrode moving device 10 for moving the electrode 3 to change the distance between the grindstone 2 and the electrode 3, and the electrode 3 and the grindstone 2. A position control device 2 that outputs a movement signal to the electrode moving device 10 so that this detected value falls within a set range.
It has 0 and. Thereby, the interval between the grindstone 2 and the electrode 3 can be automatically adjusted so that the current or voltage between the electrode 3 and the grindstone 2 falls within the set range.

The position control device 20, as shown in FIG.
It is provided between the electrode 3 and the power supply 6 and the power source 5, and the electrode 3
The current or voltage between the wheel and the grindstone 2 can be detected. (A) Calibration, (B) Manual,
It has four control modes: (C) current control and (D) voltage control. Reference numeral 22 is a moving device control line for transmitting a signal between the electrode moving device 10 and the position control device 20. In the calibration mode (A), the electrode 3 is brought into contact with the grindstone 2 and the electrode moving device 10 is controlled so that the position thereof becomes zero (0). Manual mode (B)
Then, the electrode moving device 10 is controlled manually or by setting a digital switch or the like, and the electrode 3 made of, for example, graphite is used.
The shape can be corrected. Current control mode (C)
Then, when the detected current value becomes larger than the set range, the electrode moving device 10 is arranged so as to increase the distance between the grindstone 2 and the electrode 3.
When the current value becomes smaller than the set range, the movement signal is output to the electrode moving device 10 so as to reduce the distance between the grindstone 2 and the electrode 3. The current setting range is preferably about ± 0.1 A with respect to the set value of 1 A, for example. Furthermore,
In the voltage control mode (D), when the detected voltage value becomes larger than the set range, a movement signal is output to the electrode moving device 10 so as to reduce the interval between the grindstone 2 and the electrode 3, and when the voltage value becomes smaller than the set range, the grindstone becomes smaller. A movement signal is output to the electrode moving device 10 so as to increase the distance between the electrode 2 and the electrode 3. The setting range of voltage is ± 1V with respect to the setting value of 40V, for example.
The degree is good. Further, it is preferable that a power supply control line 21 connecting the position control device 20 and the power supply 5 is provided so that the position control device 20 can control ON / OFF of the power supply 5.

FIG. 2 is an overall configuration diagram of the electrode moving device 10. Although the electrode moving device 10 is shown in the horizontal position in this figure, it may be used in the vertical position as shown in FIG. In FIG. 2, the electrode moving device 10 includes a support member 12 that slidably supports the electrode 3 from a position in close contact with the grindstone 2 to a position spaced from the grindstone 2, and a sliding direction of the support member 12 (vertical direction in the drawing). The taper member 14 is slidably supported in a direction (horizontal direction in the drawing) orthogonal to and a driving device 16 that moves the taper member 14 according to the output of the position control device 20. The support member 12 is an overall mouth-shaped member in which the electrode 3 and the horizontal member 12a are connected by two parallel shafts 12b, and the two shafts 12b are linear guides 11a fixed to the main body 11. Is supported so as to be slidable in the vertical direction in the figure. A cylindrical roller 13 is rotatably attached to the support member 12 so as to be rotatable about a horizontal shaft. The taper member 14 is a member having an elongated rectangular cross section as a whole, and has a taper surface 14 a on its upper surface that engages with the outer peripheral surface of the roller 13. A slide guide 14b is fixed to the lower surface of the taper member 14, and the slide guide 14b engages with a rail 11b fixed to the main body 11,
It can slide in a direction (right and left in the figure) orthogonal to the sliding direction of the support member 12. The drive device 16 includes an elongated male screw member 18 that is rotationally driven by a pulse motor 17.
The male screw member 18 is screwed with a female screw member (not shown) provided at the right end of the taper member 14.
The pulse motor 17 and the male screw member 18 are adapted to transmit the rotation connected by an appropriate coupling 18a without error such as backlash. The male screw member 18 is rotatably supported by a bearing 19 fixed to the main body 11. Further, the pulse motor 17 is a double shaft type, and a manual knob 22 for manual operation is attached to the outer shaft thereof.

With the above configuration, when the pulse motor 17 is rotated by the output signal of the position control device 20, the male screw member 18 is rotated and the taper member 14 is moved left and right,
The support member 12 moves up and down by the engagement between the tapered surface 14a of the taper member 14 and the roller 13 to move the electrode 3 up and down, thereby changing the distance between the grindstone 2 and the electrode 3. A compression spring 23 is sandwiched between the main body 11 and the horizontal member 12a, and the electrode 3 when the taper member 14 moves to the right.
Smoothing down (returning). The output signal of the position control device 20, that is, the input signal to the pulse motor 17 is
It is a pulse signal, and the pulse motor 17
Is rotated to move the electrode 3 up and down. The electrode 3 may be moved up and down by directly rotating the manual knob 22 by hand. In the above example, the open loop control using the pulse motor 17 is shown, but a normal small motor is used instead of the pulse motor, and a pulse signal is extracted from the rotation of the male screw member 18 to control the rotation of the small motor. Closed loop control may be used.

Using the apparatus shown in FIGS. 1 and 2, a grindstone 2
While a conductive liquid is allowed to flow between the grinding wheel 2 and the electrode 3, a voltage is applied between the grinding wheel 2 and the electrode 3, and the grinding wheel 2 is electrolytically dressed to grind the work 1. Further, in the method of the present invention, the position controller 20 detects the current or voltage between the electrode 3 and the grindstone 2, and adjusts the interval between the grindstone 2 and the electrode 3 so that the detected value falls within the set range. By this method,
The distance between the grindstone and the electrode can be automatically adjusted so that the current or voltage between the electrode and the grindstone falls within the set range.

[0012]

As described above, according to the method and apparatus of the present invention, the distance between the grindstone and the electrode is automatically adjusted so that the current or voltage between the electrode and the grindstone falls within the set range.
Even if the setting range of the current is increased to increase the grinding efficiency, the current is automatically controlled within the setting range. Therefore, the method and apparatus of the present invention have excellent effects such that the current does not become too high, the film is stably formed, and ELID grinding can be stably and efficiently performed. Have.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an electrolytic dressing control device according to the present invention.

FIG. 2 is an overall configuration diagram of an electrode moving device 10.

FIG. 3 is a schematic diagram showing changes in current and voltage in ELID grinding.

FIG. 4 is an explanatory diagram showing an ELID cycle in an ELID grinding method.

[Explanation of symbols]

 1 Work 2 Whetstone 3 Electrode 4 Nozzle 5 Power Supply 6 Feeder 10 Electrode Moving Device 11 Main Body 12 Supporting Member 13 Roller 14 Taper Member 16 Drive Device 17 Pulse Motor 18 Male Screw Member 19 Bearing 20 Position Control Device 21 Power Control Line 22 Manual Knob 23 Compression spring

Claims (6)

[Claims] 1. An electrode and a grindstone in electrolytic dressing grinding in which a conductive liquid is caused to flow between the grindstone and the electrode, a voltage is applied between the grindstone and the electrode, and the work is ground while dressing the grindstone by electrolysis. An electrolytic dressing control method comprising detecting a current or a voltage between them and adjusting a distance between the grindstone and the electrode so that the detected value falls within a set range. 2. A grindstone having a contact surface with a work, an electrode facing the grindstone with a gap, a nozzle for flowing a conductive liquid between the grindstone and the electrode, and a voltage applied between the grindstone and the electrode. In electrolytic dressing grinding, which consists of a power source and a power supply to apply, grinds the workpiece while dressing the grindstone by electrolysis, an electrode moving device that moves the electrode to change the distance between the grindstone and the electrode, and between the electrode and the grindstone. A position control device that detects a current or a voltage and outputs a movement signal to the electrode moving device so that the detected value falls within a set range, and thereby the grindstone so that the detected value falls within the set range. An electrolytic dressing control device characterized by adjusting a distance between electrodes. 3. The position control device is provided between an electrode and a power supply, and a power source, and moves to an electrode moving device so as to increase a distance between the grindstone and the electrode when a detected current value becomes larger than a set range. 3. The electrolytic dressing control device according to claim 2, wherein a signal is output and a movement signal is output to the electrode moving device so as to reduce a gap between the grindstone and the electrode when the current value becomes smaller than a set range. . 4. The position control device is provided between an electrode and a power supply, and a power supply, and moves to an electrode moving device so as to reduce a distance between the grindstone and the electrode when the detected voltage value exceeds a set range. 3. The electrolytic dressing control device according to claim 2, wherein a signal is output, and a movement signal is output to the electrode moving device so as to increase a gap between the grindstone and the electrode when the voltage value becomes smaller than a set range. . 5. The electrode moving device includes a support member slidably supporting an electrode from a position in close contact with a grindstone to a position spaced from the grindstone, and slidable in a direction orthogonal to a sliding direction of the support member. And a drive device for moving the taper member according to the output of the position control device. A cylindrical roller is rotatably attached to the support member. The electrolytic dressing control device according to claim 2, wherein has a tapered surface that engages with an outer peripheral surface of the roller. 6. The drive device has an elongated male screw member that is rotationally driven by a pulse motor, and the male screw member is screwed with a female screw member provided on the taper member. The electrolytic dressing control device according to claim 5.