JP2001179543A - Electrochemical method and device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the productivity, and to improve the working accuracy of products in an electrochemical method of arranging an electrode formed into the predetermined shape and a work opposite to each other with a fine clearance and relatively feeding the electrode in relation to the work while flowing the electrolyte at a high speed in that clearance and while applying the direct current working voltage to the electrode and the work for working. SOLUTION: Electric variable obtained on the basis of an integrated value of the direct current working current with the electrifying time is monitored, and working conclusion time is decided on the basis of this electric variable. The working conclusion time is decided when a detected electric variable achieves the preset value. In this case, relative feeding quantity of the electrode is monitored while monitoring the electric variable, and the working can be concluded when at least any one of the electric variable and the feeding quantity coincides with each set value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic processing method and an electrolytic processing apparatus capable of accurately controlling a processing amount of a workpiece.

[0002]

2. Description of the Related Art An electrolytic machining method is known as one of precision machining methods for metal products. In this electrolytic processing method, a workpiece is opposed to an electrode formed in a predetermined shape with a minute gap, an electrolytic solution is flowed at a high speed in this gap, the electrode is a cathode, and the workpiece is applied to an anode. To dissolve the workpiece (anode metal).

If the electrode is relatively sent toward the workpiece during the melting, the workpiece is processed into a shape substantially matching the shape of the electrode when the electrode reaches a predetermined processing depth.
This method utilizes a dissolution phenomenon of an anode metal in electroplating, and an aqueous solution of sodium chloride or sodium nitrate is used as an electrolytic solution. The electrolyte is usually jetted into the gap at a pressure of 12 kg / cm ² and flows through the gap at a high speed.

In this method, the electrolytic solution flows into the gap at a high speed during the processing, so that it is impossible to visually observe the progress of the processing. Therefore, conventionally, an operation of interrupting the processing after performing an appropriate amount of processing, separating the electrode from the workpiece, taking out the workpiece, and measuring the processing amount with a measuring device has been repeated many times. In other words, try and
The processing amount was confirmed by the error method.

[0005] Further, a method of monitoring a feed amount (position change amount) of an electrode and terminating the processing when the feed amount reaches a predetermined amount has been also performed. That is, the limit position of the electrode is stored in the apparatus in advance, and the processing is terminated when the electrode comes to the limit position during the actual processing.

[0006]

According to the above-mentioned try-and-error method, the machining must be interrupted many times and the machining amount must be measured, which complicates the operation and extremely deteriorates the productivity. There was a problem of becoming. In the method of monitoring the feed amount (position change amount) of the electrode, it goes without saying that the processing amount changes due to an incorrect setting of the measurement start position of the feed amount or a slight shift of the fixed position of the workpiece. However, it is inevitable that the workpiece will be distorted by various conditions such as heat that gradually changes due to energization during processing, and this distortion directly changes the amount of processing. For this reason, it is difficult to control the processing amount with high accuracy only by monitoring the feed amount.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and it is a first object of the present invention to provide an electrolytic processing method which has good productivity and can improve the processing accuracy of a product. It is a second object of the present invention to provide an electrolytic processing apparatus used directly for carrying out this method.

[0008]

According to the present invention, a first object is to make an electrode formed into a predetermined shape and a workpiece face each other via a minute gap, to flow an electrolytic solution through this gap at a high speed, and to cover the electrode with the workpiece. In an electrolytic machining method for machining by applying an electrode relative to a workpiece while applying a DC machining voltage to the workpiece, in the electrolytic machining method, an amount of electricity determined by an integrated value of the DC machining current and the energizing time is monitored. The electrolytic processing method is characterized in that a processing end point is determined based on the quantity of electricity.

The end of machining can be determined based on the fact that the detected amount of electricity has reached a preset value. Here, the set value can be determined by performing test processing on a test workpiece.
Since the DC machining current fluctuates during machining, in this case, the integral value obtained by integrating the DC machining current with respect to time may be used as the electric quantity. In this case, the relative feed amount of the electrode may be monitored in parallel with the monitoring by the electric amount, and the processing may be terminated when at least one of the electric amount and the feed amount matches the respective set value.

A second object is to cause an electrode formed into a predetermined shape and a workpiece to face each other with a minute gap therebetween, to flow an electrolytic solution through this gap at a high speed, and to apply a DC voltage to the electrode and the workpiece. In an electrolytic processing apparatus that performs processing by feeding an electrode relative to a workpiece while adding, a current detection unit that detects a current flowing between the electrode and the workpiece,
An electric quantity detection unit that obtains a product of the current detected by the current detector and time and uses the product as an electric quantity, and an electric quantity set value storage that stores an electric quantity corresponding to an appropriate machining amount of the workpiece as a set value. Unit, a first comparison unit that outputs a processing end signal when the electric amount obtained by the electric amount detection unit reaches the set value of the electric amount, and starts processing based on a start signal and outputs the processing end signal. And a controller for stopping the processing based on the information.

[0011] An actual amount of processing is actually performed on a test workpiece to determine the amount of electricity at that time, and this amount of electricity can be used as a set value. Here, a feed amount detection unit, a feed amount set value storage unit that stores a feed amount corresponding to an appropriate processing amount, and a second comparison unit that outputs a processing end signal when the feed amount reaches the set value of the feed amount. And the controller may be configured to stop the processing based on a processing end signal output by at least one of the first and second comparison units.

[0012]

[Principle] Here, the principle of the present invention will be described. Faraday's law is known for electrolysis. Faraday's law states that in the electrolysis of an electrolyte solution, the amount of elements or atomic groups that precipitate (discharge at the electrode) is
The amount of electricity required to deposit one gram equivalent of an element or group is proportional to the amount of electricity (product of current and time) and is always constant irrespective of the type of element or group (Faraday Is a constant F).

According to this law, the amount of electricity required to elute one gram equivalent of an element is F (Faraday constant) Coulomb, and one gram of an element having a valence of n and an atomic weight of M is n.
/ M gram equivalent, the amount of electricity required to elute 1 gram of this element is nF / M coulomb. Therefore, if the amount of the element eluted by the current of I amperes flowing for t seconds is represented by w grams, then It = wnF / M.

In this case, if the volume removed from the workpiece (removed volume) is V ₀ and the density of the element is γ, then V ₀ = M
It / (nFγ). The volume V ₀ thus determined
Is a theoretical value, but the actual removal volume V can be estimated by multiplying this by various correction coefficients, correction coefficients, and the like.

According to the present invention, the amount of electrolytic machining is estimated by monitoring the amount of electricity It to prevent the machining amount from becoming insufficient or excessive. In this case, the electric quantity E corresponding to an appropriate processing amount is preferably obtained by actually processing a test workpiece (the same workpiece as a product) in advance. The amount of electricity E required to obtain the appropriate amount of machining is stored as a set value E ₀ , and processing is performed on the workpiece to be processed until the amount of electricity E matches the set value E _0. To end the processing. Thus, if the set value E ₀ is obtained by actual processing, it is not necessary to consider all the effects of the correction coefficient and the correction coefficient on the theoretical value, and high-precision processing can be performed.

[0016]

FIG. 1 is a conceptual diagram of an electrolytic processing apparatus according to an embodiment of the present invention, FIG. 2 is a flowchart showing its operation, and FIG. 3 is a diagram showing an example of the configuration of an operation panel of this apparatus.

In FIG. 1, reference numeral 10 denotes a workpiece, and 12 denotes an electrode. The workpiece 10 is usually a difficult-to-cut material, and is a target to be subjected to engraving such as a forging die, a glass die, a plastic molding die, a rubber molding die, or deburring.
It is an object to be subjected to flaw removal, groove processing, deep hole processing and the like.
The electrode 12 is made of a metal having low specific resistance, excellent workability, and high strength and corrosion resistance, for example, brass.

Reference numeral 14 denotes an electrolytic solution tank. The workpiece 10 is immersed in the electrolytic solution in the electrolytic solution tank 14 and is held with its processed surface facing upward. The electrode 12 is held so as to be able to move up and down from above so that the processing surface faces the upper surface of the workpiece 10. The electrode 12 is driven up and down by a servomotor 16.

The electrode 12 has an electrolyte solution channel 12A. Electrolyte is pumped from one end of the electrolyte flow path 12A by a pump 22 through a filter 20 from an electrolyte storage tank 18. The other end of the electrolyte solution channel 12A is provided with a gap 24 formed between the processing surfaces of the electrode 12 and the workpiece 10.
It is open to. For this reason, the electrolytic solution pumped by the pump 22 is jetted into the gap 24 to generate a high-speed flow of the electrolytic solution in the gap 24. The electrolytic solution flowing into the electrolytic solution tank 14 from the gap 24 returns to the electrolytic solution storage tank 18 and returns to the electrolytic solution tank 14 through the electrode 12.

Reference numeral 26 denotes a power supply circuit. This power supply circuit 26
For example, a rectifier circuit for rectifying an alternating current introduced from a three-phase AC power supply 28 and a constant voltage circuit for setting the output of the rectifier circuit to a constant DC voltage. This power supply circuit 26
Has a positive output terminal connected to the workpiece 10 and a negative output terminal connected to the electrode 12.

Reference numeral 30 denotes an electric quantity detection unit, and 32 denotes a current detection unit. The electric quantity detection unit 30 includes the workpiece 10 and the electrode 1
DC current (machining current) I flowing between them and time t (sec)
ond, seconds). That is, an integrated value ∫Idt (ampere-second) obtained by integrating the current I with time t (unit is second)
Is calculated. This integral value is defined as an electric quantity E. That is, E = ∫I · dt. The current detection unit 32 detects the current I supplied from the power supply circuit 26,
(Current Transformer), CT (Hall CT, HCT) using Hall elements, and the like.

Reference numeral 34 denotes a setting unit (set value storage unit) for storing the set value E ₀ . This set value E ₀ is obtained as follows. That is, the electric detection unit 30 obtains the amount of electricity E when the test workpiece 10 is actually machined to obtain the machining amount corresponding to the optimum feeding, and the electricity amount E is set to the set value E _0. Is stored in the setting unit 34.

Reference numeral 36 denotes a first comparator, which compares the electric quantity E obtained by the electric quantity detection unit 30 with a set value E _0, and outputs a machining end signal A when the electric quantity E reaches the set value E _0. Output. Reference numeral 38 denotes a controller which starts the apparatus based on a start signal, and outputs a stop signal or a processing end signal A.
Processing is stopped based on.

The operation panel 40 of the controller 38 is shown in FIG.
It is configured as shown in FIG. In FIG. 3, reference numeral 42 denotes an electric quantity display, which displays the actual electric quantity E which the electric quantity detection unit 30 sequentially obtains during machining. A set value display 44 displays the set value E ₀ stored in the set device 34.
These indicators 42 and 44 are displayed as KIt (kiloampere seconds =
It is expressed in units of 10 ³ It).

Reference numerals 46 and 48 denote reset buttons for resetting the displays on the indicators 42 and 44. That reset button 46 resets the display 42, a reset button 48 allows the setting of a new set value E ₀ resets the indicator 44.

Reference numeral 50 denotes a set value input button, and reference numeral 52 denotes a numeric keypad. The set value input button 50 is used to reset the set value E ₀ when the display 44 is cleared by the reset button 48. For example, a new set value E
By inputting ₀ and pressing this button 50, this can be stored in the setting device 34 and displayed on the display device 44. Since the electric quantity E when the test workpiece 10 is actually processed is displayed on the display 42, the electric quantity displayed on the display 42 at this time is inputted from the ten keys 52 and the setting unit 34 is set. And display it on the display 44. At this time, the display 4
An electric quantity (E + α) determined to be slightly larger or smaller than the actual electric quantity E displayed in 2 may be used as the set value E ₀ .

Reference numeral 54 denotes a start switch, 56 denotes a stop switch, and 58 denotes an emergency stop switch. By pressing the start switch 54, a start signal is input to the controller 38, and electrolytic processing is started. In addition, a stop signal is output from the
, The machining is stopped, but the controller 38 also stops the machining when the comparator 36 outputs the machining end signal A as described above.

Next, the operation of this apparatus will be described with reference to FIG. First, the indicators 42 and 44 are cleared by the reset buttons 46 and 48. And the set value E ₀
Perform test processing to determine (Step S10)
0). That is, the same workpiece 10 as the product is set in the electrolytic solution tank 14 for testing, and the processing is started by pressing the start switch 54.

When it is considered that a processing amount slightly smaller than an appropriate processing amount can be obtained, the stop switch 56 is pressed to stop the processing, the processing amount is measured, and the processing is repeated until the target processing amount is reached. When the target processing amount is obtained, the electric quantity E displayed on the display 42 is read. Then, the set value E ₀ is determined by making some corrections based on the electric quantity E. The set value E ₀ is displayed on the display 44 by inputting with the ten keys 52. Then, when the set value input button 50 is pressed, the set value E ₀ displayed on the display 44 is stored in the set unit 34 (step S102).

After that, the workpiece 10 is replaced with a product, and if the start switch 54 is pressed, the processing of the product is started (step S104). During this processing, the electric quantity E is calculated and displayed on the display 42 (step S10).
6). When E ≧ E ₀ , the comparator 36 outputs a processing end signal A (step S108). The controller 38 stops machining based on the signal A (step S11).
0). If there is another workpiece 10 (step S10
2) The workpiece 10 is exchanged (step S114), and the above-mentioned processing from step S104 is repeated. When the processing on all the workpieces 10 is completed, all the operations are stopped.

[0031]

FIG. 4 is a conceptual diagram of another embodiment.
In this embodiment, in the embodiment of FIGS. 1 to 3, not only the amount of electricity but also the relative feed amount of the electrode is monitored, and the machining is terminated when at least one of the amount of electricity and the amount of feed reaches the respective set value. It was made.
That is, a feed amount detection unit 70 that detects a relative feed amount x of the electrode 12, a feed amount set value storage unit 72,
A second comparison unit 74 has been added.

Here, the feed amount detecting unit 70 is a motor 16
The rotary encoder is provided to detect a feed amount from the rotation amount of the motor 16. Feed amount set value x ₀ is an infeed amount corresponding to the proper working of the workpiece is determined by the test processing. Second
The comparison unit 74 outputs a processing end signal B actually obtained feed amount x reaches the set value x ₀ narrowing feed during processing. In this embodiment, the controller 38A stops the processing when at least one of the first and second comparison units 36 and 74 outputs the processing end signal A or B. The controller 38A may stop the processing when the processing end signals A and B are output.

[0033]

According to the first aspect of the present invention, as described above, the end point of machining is determined based on the quantity of electricity which is the product of the electrolytic machining current and the energizing time. Also, it is possible to perform the processing efficiently without interrupting the processing and checking the processing amount, thereby improving the productivity. In addition, the processing accuracy can be improved by appropriately setting the amount of electricity for terminating the processing.

The amount of electricity for determining the end point of machining is obtained by machining the test workpiece, and the quantity of electricity is set as a set value. If the processing is terminated when the set value is reached, it is preferable to prevent the processing amount from becoming excessive (claim 2). In this case, by making the workpieces for the test and the product the same, it is possible to match the processing amounts of the test and the product with extremely high precision. Here, the quantity of electricity can be obtained by integrating the machining current with time (claim 3).

It is also possible to monitor the relative feed amount of the electrode together with the amount of electricity, and terminate the machining when at least one of the amount of electricity and the amount of feed coincides with each set value. The processing may be terminated after both the electric amount and the feed amount match the respective set values.

According to the fifth aspect of the present invention, there is provided an electrolytic processing apparatus directly used for carrying out this method. Here, it is preferable to actually process the same test workpiece as that for the product, obtain an amount of electricity at which the processing amount at that time is appropriate, and use this as a set value (claim 6). In order to monitor the feed amount together with the electric amount and terminate the processing when at least one of the electric amount and the feed amount matches the set value, the feed amount detecting unit, the feed amount set value storage unit, and the second comparison unit The processing may be terminated when at least one of the first and second comparison units outputs a processing end signal (claim 7).

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of one embodiment of the present invention.

FIG. 2 is a flowchart of the operation.

FIG. 3 is a diagram showing a configuration example of a controller operation panel.

FIG. 4 is a conceptual diagram of another embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Workpiece 12 Electrode 14 Electrolyte tank 24 Gap 26 Power supply circuit (constant voltage circuit) 30 Electric quantity detection part 32 Current detection part 34 Setting device (Setting value storage part) 36 First comparator (Comparison part) 38 Controller 70 Feed amount detection unit 72 Feed amount set value storage unit 74 Second comparison unit A, B Processing end signal E Electric amount E ₀ Electric amount set value x ₀ Feed amount set value

Claims (7)

[Claims] An electrode formed into a predetermined shape and a workpiece are opposed to each other via a minute gap, and an electrolytic solution is caused to flow through the gap at a high speed, and a DC machining voltage is applied to the electrode and the workpiece. In the electrolytic machining method of machining by feeding relatively to the workpiece, the amount of electricity obtained by the integrated value of the DC machining current and the energizing time is monitored, and the machining is terminated based on the amount of electricity. The electrolytic processing method characterized in that: 2. An electric quantity at the time of test-working a test workpiece is set as a set value, and the processing is terminated when an electric quantity obtained during processing of the product-workpiece matches the set value. The electrolytic processing method according to claim 1. 3. The electrolytic machining method according to claim 1, wherein the amount of electricity is obtained by integrating the machining current with time. 4. The method according to claim 1, wherein the electric quantity and the relative feed amount of the electrode are monitored, and the machining is terminated when at least one of the electric quantity and the feed amount matches the corresponding set value.
Any of the electrolytic processing methods. 5. An electrode formed into a predetermined shape and a workpiece are opposed to each other via a minute gap, and an electrolyte is caused to flow through the gap at a high speed, and the electrode is applied while applying a DC voltage to the electrode and the workpiece. In an electrolytic processing apparatus that performs processing by feeding relative to a workpiece, a current detection unit that detects a current flowing between the electrode and the workpiece, and a current and time detected by the current detector. The electric quantity detection unit which obtains the product of the electric quantity and the electric quantity detection unit, the electric quantity set value storage unit which stores the electric quantity corresponding to the appropriate machining amount of the workpiece as the set value, and the electric quantity detection unit A first comparing unit that outputs a machining end signal when the electric quantity reaches the set value of the electric quantity; and a controller that starts machining based on a start signal and stops machining based on the machining end signal. Electrolytic process characterized by Apparatus. 6. The electrolytic processing apparatus according to claim 5, wherein the set value is set as an amount of electricity at which a work piece for testing that is the same as the work piece for product is actually machined and the machining amount is appropriate. 7. A feed amount detecting unit for monitoring a relative feed amount of an electrode according to claim 5 or 6, and a feed amount set value storage for storing a feed amount corresponding to an appropriate processing amount of a workpiece as a set value. And a second comparison unit that outputs a machining end signal when the feed amount obtained by the feed amount detection unit reaches the set value of the feed amount, and the controller is configured to control the first and second comparison units. An electrolytic processing apparatus that stops processing based on a processing end signal output by at least one of the processing.