JPS6246288B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrochemical processing device that performs processing based on electrolysis of an electrolytic solution or an electrodeposition solution, such as die engraving, deburring, electrolytic polishing, cutting, or electrodeposition. .

Conventionally, it is known to use electrolytic energization pulses. Conventional pulse power sources provide constant frequency pulse energization configured by DC + AC, half-wave rectification of AC, on/off switching control of a switch controlled by constant frequency oscillation, and the like. The electrolytic gap is generally 1 mm or less, usually 0.02 to 0.7 mm, and is a minute gap of several mm at most. The gap length is controlled to be maintained by applying servo feed to the opposing electrodes or the workpiece. Also, in the electrodeposition process, an example is given in Japanese Patent Publication No. 70-8801 in which electrodeposition is performed while retracting the electrode using servo feeding, but in general, a large number of electrode rods are arranged in rows and columns on an energizing bar. However, devices in which the interval length can be adjusted by hand are in practical use. In any case, if you try to control servo feed in response to changes in interval length, servo feed will be controlled on average (average over a relatively long period of several seconds or more) due to the relationship between feed speed and feed inertia. Even if it is constant, it cannot respond to momentary changes and is difficult to follow with fine servo feed. However, since a current is passed at a high current density in a pulsed manner through the gap between the electrode and the workpiece (base material), even a slight change in the gap length causes a large change in the pulsed current. If the energization state of the gap changes slightly in this way, it becomes impossible to perform electrolytic processing with constant precision and surface roughness, and electrodeposition with a constant density becomes impossible, making it impossible to perform electrochemical processing for the intended purpose. There are drawbacks that go away.

The present invention corresponds to momentary gap changes during servo feeding, and changes the pause width of the machining pulse voltage applied to the gap to make it appear as if the gap did not change. In addition, since the pause width of the gap machining pulse voltage is controlled, the servo becomes smooth and constant, making it appear as if constant feed is being performed. This was proposed to improve electrodeposition so that even if the gap between the electrode and the workpiece narrows, electrodeposition is performed at a constant gap. The pause width τoff of the machining pulse, the voltage, or both are controlled in response to changes in the gap length through which the machining pulse flows. The control includes a control circuit that generates a pulse voltage pause width τoff at a normal gap length, and a control circuit that generates a pulse voltage pause width τoff when the gap length becomes narrow. a control circuit that makes the pulse voltage pause width τoff smaller than the pulse voltage pause width τoff when the gap length becomes wider than the pulse voltage pause width τoff at the normal gap length; A switch for controlling on/off of the electrode, a DC power source, and a discrimination circuit for discriminating the gap length between the electrode and the workpiece, and the control circuit is selected based on the discrimination output of the discrimination circuit to perform pulse energization. This feature allows a constant current to flow, which enables high-precision, high-density electrochemical processing.

The present invention will be explained below with reference to an embodiment of the drawings. 1 is an electrolytic gap between an electrode and a workpiece (base material) facing each other, 2 is a DC power source, which is controlled on and off by a switch to generate machining pulses. do. 31,
32 and 33 are transistor switches, which are controlled on and off by a pulser 4 such as a multivibrator, and repeatedly generate predetermined processing pulses. 5 is the off pulse τ of multivibrator 4
A control circuit that controls switching off of the switch 51,
At 52 and 53, switching control of the oscillation constant is performed. τoff becomes the minimum when the switch 51 is turned on, and becomes the maximum when the switch 53 is turned on, and is set to 51<52<53.
is the rest width τ of the pulse voltage at the normal gap length
Generates off. 61, 62, 63 switch the oscillation output of the multivibrator 4 to switches 31, 3, respectively.
With an AND gate added to 2, 33, terminals a, b,
The AND gate is operated by any one of the signals c, and the switches 31, 32, and 33 are controlled to be selected. 7 is the power supply for inspection and switches 31, 3
Control is performed to select 2 and 33. 7 is a power supply for inspection, which is connected to gap 1 via switch 8, and switch 8 is controlled on/off by a signal obtained by inverting the output gate pulse of multivibrator 4 with switch 9, and inspection is performed while the machining pulse is paused. A voltage is applied to gap 1. 10 is a resistor that detects the voltage in gap 1, and 11 is activated by the output gate pulse of multivibrator 4, and is turned on while the machining pulse is applied to gap 1, shunting the detection resistor 10, and detecting the machining pulse. Switches 121, 122, and 123, which are turned off only during rest, each have a detection resistor 1.
This is a discrimination circuit for discriminating a detection voltage of 0, and is constructed of, for example, a Schmitt.The discrimination reference voltage is set to 121>122>123, with 121 being the highest, 123 being the minimum, and 122 being the voltage at the normal gap. The discrimination outputs are output to terminals a, b, and c, respectively.

In electrolytic processing, a gate pulse having a predetermined pulse width τon and rest width τoff is selected by the control circuit 5 by the oscillation of the multivibrator 4, and the switch 3
In addition, by this on/off switching control, machining pulses of predetermined τon and τoff of the DC power supply 2 are added to the gap 1, and electrolysis is performed by passing a pulsed current through the electrolytic solution supplied to the gap 1. Then, anodic melting processing is performed. Electrodeposition can be performed by reversing the conductivity and using a plating solution with the base material side as the negative electrode.

The length of the gap 1 between the electrode and the workpiece facing each other during processing is inspected as follows. That is, every time the machining pulse is paused, the switch 8 is turned on and the test voltage 7 is applied to the gap 1. Also, the switch 11 is turned off and the detection resistor 1 connected in parallel to the gap 1 is turned off.
0 detects the voltage across gap 1. Since the detection voltage of the gap 1 during the energization period detected here is proportional to the gap length, the gap length can be easily inspected and detected by discriminating the detection voltage of the detection resistor 10 by the discrimination circuits 121, 122, and 123. can do.
Each discrimination criterion value of the discrimination circuit is 121 as described above.
>122>123, but now if the discrimination criterion of 122 is set to the test voltage of the normal gap length, when the gap length is normal and the detection voltage of the detection resistor 10 is the normal value, the terminal will be output from the discrimination circuit 122. A control signal is output to b, and the pause width τ of the multivibrator 4 is
The switch 52 of the control circuit 5 which determines off is turned on to set a predetermined pause width τoff. Pulse width τon and pause width τoff of machining pulse at normal gap length
is normally set at a ratio of about 1:1, so by turning on switch 52 now, τ
If on and τoff are set at 1:1, the processing pulses by switch 3 controlled on/off by multivibrator 4 are repeatedly supplied to gap 1 with τon and τoff in a 1:1 ratio. and processing is performed. This machining pulse is τon in Fig. 2B.
and τoff are equal.

At this time, a signal is applied to the terminal b of the switch that generates the processing pulse, and the AND gate 62 is activated, and a pulse signal is applied to the switch 32, and the switch is turned on.
The voltage of the DC power source 2 is applied to the gap 1 as a machining pulse under off-switching control. Each switch 3
A resistor is inserted in series with 1, 32, and 33 to adjust the voltage and supply a pulse to gap 1, and the generated voltage is set to 31>32>33.
By controlling the switch 32, a normal predetermined voltage pulse is supplied.

Next, if the gap length is wider than a predetermined value by inspection and detection of the machining gap 1, the voltage of the detection resistor 10 increases, and as a result, the discrimination circuit 121 outputs an output, and due to the discrimination operation, the control circuit 5 and a signal is applied to the terminal a of the AND gate 61. By operating the switch 51, the pause width τoff is shortened, and by applying a signal to the AND gate 61 and operating the switch 31, a pulse voltage adjusted in the increasing direction is applied to the gap 1. The pulse waveform at that time is shown in FIG. 2A. At this time, by controlling the pause width τoff to be short, the width of the gap 1 increases, which increases the effect of removing machining debris and renewing the new liquid, and reduces the occurrence of short circuits and arcs, so the supplied machining pulse width τon In addition, increasing the pulse voltage prevents the pulse current from decreasing due to the widening of the gap 1, and ensures that the same level of current is passed through the normal gap. The voltage value is optimally set by adjusting the series resistance of switch 31. On the other hand, when the gap 1 narrows, the voltage across the detection resistor 10 decreases, and the discrimination circuit 123 discriminates this and outputs a signal to the terminal c. As a result, the switch 53 of the control circuit 5 is operated to increase the pause width τoff, and the AND gate 63 is activated.
The processing pulse shown in FIG. 2c is supplied to the gap 1 under the control of the switch 33 as shown in FIG. As the gap length narrows, the removal effect of processing debris in gap 1 deteriorates, and the electrolyte distribution effect also deteriorates, so at this time, the pause width τoff is controlled to be long, and a large amount of liquid is renewed during this pause. Perform purification. Also, because the gap has become narrower, current is in a state where it is easier to flow, so the pulse voltage is adjusted to be lower so that the current value approaches the normal gap length to prevent large current flow exceeding a predetermined current. .

The pause width τoff is controlled at a normal gap length, for example, equal to the pulse width τon, 1:1, whereas when gap 1 widens, it is 0.3:1, and when gap 1 narrows, it is 5:1. For example, τ
When Cu was electrodeposited by pulsed current on for 10 μs, an extremely good electrodeposited layer was obtained by simply controlling τoff. Of course, even better results can be obtained by controlling the voltage at the same time as controlling τoff.

As described above, the detection resistor 10 and the discrimination circuits 121, 122, and 123 that discriminate the detection voltage thereof inspect and detect the change in the width of the gap 1 and the gap length.
When the pulse width is widened, τoff is decreased, and along with this, or by changing to this τoff control, the voltage of the pulse is controlled to be low when the pulse width is narrowed, and the voltage is high when the pulse width is widened.

Due to this voltage control, the peak value of the current flowing through gap 1 remains almost constant regardless of changes in gap length, which enables stable and good electrochemical processing, with high accuracy in electrolytic processing and high density in electrodeposition. This has the effect of forming an electrodeposited layer with high precision.

The gap length can be easily detected by detecting and determining gap impedance, resistance, voltage, current changes, liquid discharge, high frequency components, etc. , a pilot pulse with a set voltage is applied to the gap, and it can be determined by the change in voltage and current.
According to experiments, accurate detection was possible by applying a 20V pulse with a pulse width of 50μs to the gap and detecting and determining the flowing current value. Further, control of τoff and voltage based on this detection may be analog control.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration diagram of an embodiment of the present invention, and FIG. 2 is a pulse waveform explanatory diagram. 1... Gap, 2... DC power supply, 3... Switch for voltage generation having switches 31, 32, 33, 4... Pulser, 5... Control circuit having rest width τoff control switches 51, 52, 53. ,61,
62, 63...And gate, 7...Power supply for inspection, 10...Voltage detection resistor, 121,122,1
23...Discrimination circuit.

Claims (1)

[Claims] 1. In an electrochemical processing device where an electrode and a workpiece (base material) face each other and a processing pulse is applied to the gap through which an electrolytic or electrodeposited liquid flows by controlling on/off switching of a switch, normal A control circuit that generates a pulse voltage pause width τoff at a gap length, and a control circuit that generates a pulse voltage pause width τoff when the gap length becomes narrower than the pulse voltage pause width at the normal gap length. a control circuit that makes the rest width τ off of the pulse voltage smaller when the gap length becomes wider than the rest width τ off of the pulse voltage at the normal gap length;・Equipped with a switch for off-controlling, a DC power supply, and a discrimination circuit for discriminating the gap length between the electrode and the workpiece, the control circuit is selected based on the discrimination output of the discrimination circuit to perform pulse energization. Electrochemical processing equipment.