JPS5944395B2 - Electrodeposition processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION When forming an electrodeposited film by electroplating or electroforming, it is necessary to form the metal film uniformly to the same thickness as possible in each part.

However, because it is difficult to make the potential distribution uniform depending on the shape of the model surface to be electrodeposited (usually the cathode surface), there are areas that are easy to electrodeposit and areas that are difficult to electrodeposit. If a metal film is formed in a region where it is easy to form, the unevenness of the potential distribution will further increase, and there will be parts where the electrodeposited film is intensively formed and other parts where it is hardly formed. In order to solve this problem, conventional methods have been to distribute multiple anode electrodes according to the surface shape of the model (cathode matrix), to provide auxiliary electrodes, and to reduce the amount of processing fluid (electrolyte). Technological improvements have been made such as equalizing the potential distribution and varying the thickness of the electric double layer by devising supply methods and installing shielding plates. However, depending on the surface shape of the model, it is still difficult to form a uniform electrodeposited film on each part, especially when there are deep grooves or holes with narrow entrances and deep holes on the model surface. There was a problem in that it was difficult to form an electrodeposited film on the corners of the deepest bottoms of the deep grooves or deep holes, especially on the acute angles of about 900 mm or less.

The present invention is proposed with the aim of solving the problem of non-formation of electrodeposited film (shape effect) caused by the shape of the model surface, and forming a uniform electrodeposited film on each part of the model surface. The method is characterized in that the electrodeposition process is performed while an electrode having a shape corresponding to a desired part of the model surface on which the electrodeposited film is to be formed and having abrasive grains on at least the surface part is intermittently brought into contact with the desired part of the model surface. That is.

The anode electrode used in the method of the present invention can be prepared by, for example, using a model surface as a mold and filling the mold with a mixture of synthetic resin and abrasive grains, and at the same time inserting an electrode rod or a plate-shaped body with its tip end above the surface. Inserting into the mixture close to and preferably oriented to areas where it is difficult to form an electrodeposited film such as corners and corners,
After being integrated in a heated state or at room temperature, it is produced by being removed from the mold.

FIG. 1 is a cross-sectional view showing a state of manufacturing an anode corresponding to a V-shaped deep hole as a specific example of manufacturing an anode electrode.
1 is a mold and a normal model is used, 2 is a deep hole shaped part of the mold 1, 3 is a synthetic resin, 4 is abrasive grains, a mixture of both is filled in the deep hole shaped part 2, and an electrode rod Or plate-shaped body 5
is inserted into the mixture in close proximity to and preferably oriented towards the surface region z where it is most difficult to form an electrodeposited film, and after the mixture has solidified, it is removed from the deep hole-shaped portion 2 and inserted into the anode. Electrode 6 is produced. In this case, as described above, the tip of the electrode rod or plate-shaped body 5 faces the corner z of the bottom of the deep hole where an electrodeposited film is difficult to form, and the electrode rod or plate-like body 5 is placed in the model 1 so as not to directly contact the model (mold) 1. It is fixed in the electrode 6 so that it is located at some distance from the surface. Therefore, the tip of the electrode rod or plate-shaped body 5 of the anode electrode 6 taken out from the mold may be covered with resin or abrasive grains, in which case the resin or abrasive grains are removed and the electrode rod 5 is The tip is exposed so that electricity can be applied. As the electrode rod 5, in addition to a metal rod with a diameter of about 0.1 to 1 mm, a metal plate with the same thickness and a desired width, non-metallic substances such as graphite can also be used, and in the case of metal electrodes, copper In addition to insoluble electrodes that do not dissolve by electrolysis, such as titanium plated with platinum or ferrite metals, soluble electrodes made of a material to be electrodeposited may also be used.

The mixed abrasive grains are preferably insulating ones, such as SlC,
Abrasive grains such as B4C and AbO3 with a diameter of about 0.01 to 0.3 mU are used, and among them, those with a diameter of about 0.1 mU are preferred. Epoxy or phenol resins are used as the bonding molding resin, and must be chemically stable to the electrolyte. As for the mixing ratio of abrasive grains and resin, it is preferable to mix the resin in a weight ratio of about 5 to 4001) to the abrasive grains.If it is less than 5%, the mechanical strength will be insufficient, and if it is more than 40%, the resin will be mixed. The dispersion density of abrasive grains becomes insufficient. As an example, 20% by weight of phenolic resin is mixed with SiC abrasive grains with a diameter of about 0.1 WLm, and 12
Those thermally solidified at 0.00% yielded good test results and can be processed at an average current density of 0.1 A/Cflt or higher.

Since phenolic resin is dispersed at about 5000℃, S
Abrasive grains such as iC and inserted electrodes can be reused. The grindstone made of a mixture of abrasive grains and resin that constitutes the anode electrode is preferably porous in order to improve the grinding effect of the abrasive grains on the surface of the grindstone. Liquid circulation is enabled, and the machining liquid (electrolyte) can be easily supplied to the deepest part of the deep hole shape. As a means of supplying machining liquid to the deepest part of the model, in addition to making the entire grinding wheel porous, a liquid supply pipe that opens at the deepest part may be inserted into the grinding wheel. In this case, the inserted electrode rod 5 may be made into a tubular shape. By doing so, the electrode rod 5 may also be used as a liquid supply pipe. However, in the present invention, electrodeposition is performed while the anode electrode is intermittently in contact with the deep hole-shaped portion of the model surface. Since contact and separation are repeated, new machining fluid is supplied to the deepest part during this repeated contact and separation movement.
A means for supplying machining fluid to the deepest part by circulating it inside the grindstone is not necessarily required. Next, one embodiment of the method of the present invention using the above-described anode electrode will be described with reference to FIG. 2 of the drawings.

In FIG. 2, 7 is a model (workpiece) to be electroformed or plated, and 8 is a deep hole or deep groove shaped portion of the model 7. 9 is a processing tank in which the model 7 is fixedly stored.

Reference numeral 10 denotes a machining fluid (electrolytic fluid) filled in the machining tank 9, and has a circulating supply device for machining fluid to the machining tank as needed, although not shown.

Reference numeral 6 denotes an anode electrode manufactured in a shape corresponding to the deep hole-shaped portion 8 of the model 7, and is arranged at a position opposite to the deep hole-shaped portion 8.

11 is a shank that firmly supports the anode electrode 6; 12;
is a shaft driven by the registration process by the rotation of the cam 13, and both the shank 11 and the shaft 12 are configured to be freely movable in the axial direction by a cylinder 14.

15 and 16 are springs, the spring 15 acts to push the shank 11 upward, and the spring 16 acts to push the shank 1 upward.
1 and the shaft 12, and acts to push down the shank 11.

17 is a drive motor for the cam 13.

Reference numeral 18 denotes a power supply connection terminal for electrodeposition, and generally the model side is connected to the cathode and the insertion electrode 5 side is connected to the anode, but in the case of metal deposited on the anode, the connection polarity is reversed.

As a processing power source, a pulse power source is used in addition to a DC power source. Reference numeral 19 denotes a switch interposed in series in the connection circuit between the connection terminal 18 and the insertion electrode 5, and the conductive piece 20 fixed to the shank 11 performs the opening/closing operation of the contact.

With the above configuration, when the motor 17 is driven to rotate the cam 13 clockwise from the illustrated position, the shaft 12
3, and the pressing force is transmitted to the shank 11 via the spring 16.

Then, as the cam 13 rotates, when the pressing force by the spring 16 becomes greater than the force of the spring 15, the shank 11 is pushed downward, and the anode electrode 6 comes into contact with the surface of the deep hole-shaped portion 8 and is further pressed against it. This pressure contact force increases until the cam 13 rotates 900 degrees clockwise from the illustrated position and the shaft 12 moves to the lowest position.The cam 13 rotates further and the shaft 12 is pressed by the spring 16 and moves upward. decreases with
Further, the cam 13 rotates and the spring 16 against the shank 11
When the upward pressing force by the spring 15 becomes greater than the downward pressing force by the spring 15, the anode electrode 6 moves upward and is separated from the model surface. As the cam 13 rotates, the anode electrode 6 repeatedly comes into contact with and separates from the deep hole-shaped portion of the model 7 in this manner. The pressure contact force of the anode electrode 6 can be arbitrarily adjusted by appropriately selecting the constants of the springs 15 and 16, and by making the abrasive-containing resin-impregnated anode electrode 6 into a porous elastic sponge shape. Accordingly, the pressing force and the pressing state may be adjusted. however,
If the pressing force of the anode electrode 6 is too large, the surface of the model or workpiece will be ground, so it is necessary to adjust the pressing force to such an extent that this will not occur. In the electrodeposition process according to the present invention, the model (
The processing is carried out by passing a machining current between the cathode 7 and the anode 6. In this embodiment, the application of the machining current is controlled by a switch 19, and the anode 6 moves downward. When this occurs, the conductive piece 20 closes the contact of the switch 19 and the processing area is energized, and when the anode electrode 6 moves upward away from the surface of the model 7, the conductive piece 20 separates from the contact and closes the switch 19. is in an open state and no current is applied to the processing area. That is, the machining current is applied in synchronization with the registration motion of the anode electrode 6, and the current is applied only when the anode electrode 6 is positioned on the right side. The machining fluid (electrolyte) 10 is supplied to the machining area (the deepest part of the deep hole shape) by a pumping action caused by the registration motion of the anode electrode 6, and fresh machining fluid 1 is always supplied to the deepest part of the deep hole.
0 is supplied, but if the pumping action by the registering motion is not enough to supply the machining fluid, a machining fluid jetting nozzle may be separately provided to supply the machining fluid by pressurized jetting. In this case, the machining fluid jetted from the nozzle is synchronized with the registration movement of the anode electrode 6, so that when the anode electrode 6 moves upward, the machining fluid is jetted and supplied to the gap between the model 7 and the electrode 6. It's okay.

When electrodeposition processing is performed in such a state, the processing current is concentrated between the tip of the insertion electrode 5 and the angle of the deepest bottom of the deep hole, and usually the formation of the electrodeposition film is interrupted. Since the side wall surface of the deep hole, which is easily etched, is constantly lightly polished by the pressure contact of the abrasive grains on the surface of the anode electrode 6, the formation of a film by electrodeposition on the side wall surface of the deep hole is inhibited, and the bottom part of the deep hole, which is difficult to electrodeposit, is An electrodeposited film is first formed on the corner g. When a coating is formed at the corner of the deepest bottom of the deep hole, the corner gradually becomes rounded, and the shape effect that makes electrodeposition difficult to form on the concave corner g gradually decreases. do. When the film formation on the corner W has progressed and the shape effect has been sufficiently removed, the electrodeposition process using the method of the present invention is stopped, and then the entire surface of the model is electrolyzed using a conventional method. Make sure to carry out the dressing process. The registration motion of the anode electrode 6 is 0
．． Approximately 01 to 100 cycles are preferable, and the amplitude is 0.1
~100mm.

According to the experimental example, the anode electrode 6 was applied for 2.5 cycles with an amplitude of 1.
While performing registration exercise at 0 m'IL, the average current density is 0.
．． Perform electrodeposition processing at 1A/Crlt, 0.16W! l
A coating thickness formation rate of /h was obtained. When using a porous and liquid-permeable anode electrode, it is necessary to insulate the part where it is desired to prevent the formation of an electrodeposited film, and in that case, insulate the surface of the insertion electrode 5 except for the tip. mosquito,
Alternatively, the side wall surface of the anode electrode 6 except for the tip thereof is insulated, or the surface of the model except for the concave corners (portions where electrodeposited films are likely to be formed) is insulated. However, if the grindstone does not have liquid permeability and insulating abrasive grains are used, the entire grindstone becomes an insulator, so the above-mentioned insulation treatment is not necessarily required. In addition, in order to locally concentrate the machining current to the desired area, rather than making the entire grinding wheel conductive, the anode electrode 6 is arranged so that the tip of the electrode rod faces the concave corner of the model, as in the embodiment. It is preferable to insert and arrange it so that it does. The motion of the anode electrode may be such that a small amplitude, small period vibration is superimposed on a large amplitude, large period registration motion, and in addition to vertical movement, rotation or forward/backward/left/right movement may be made. You can also do it.

Also, if there are multiple concave corners on the model surface,
If a separate anode electrode is made for each concave shape and the current density of each anode electrode is controlled to be approximately equal in the processed area, uniform electrodeposition processing can be performed simultaneously on multiple concave corners. be able to. As described above, according to the present invention, film formation in areas where electrodeposited films are likely to be formed is inhibited, and while preventing the formation or abnormal growth of films in those areas, it is possible to prevent film formation in areas where electrodeposition films are likely to occur. By forming a coating on the bottom corner of the concave shape, it is possible to remove the shape effect of the corner, so even if the model has a deep hole or deep groove shape, the coating can be applied to the entire surface of the model. It is possible to form a uniform electrodeposited film.

[Brief explanation of the drawing]

FIG. 1 is a sectional view illustrating the manufacturing process of an electrode used in the present invention, and FIG. 2 is a sectional view illustrating one embodiment of the present invention. 1 is a mold, 2 is a deep hole shape, 3 is a synthetic resin, 4 is an abrasive grain, 5 is an electrode rod, 6 is an electrode, 7 is a model (workpiece), 8 is a deep hole shape, 9 is a processing tank, 10 is processing fluid, 11 is shank, 1
2 is a shaft, 13 is a cam, 14 is a cylinder, 15 and 16 are springs, 17 is a motor, 18 is a power supply connection terminal, 19 is a switch, and 20 is a conductive piece.

Claims (1)

[Claims] 1. Electrodeposition processing is performed while intermittently contacting the desired portions of the model surface with an electrode having a shape corresponding to the desired portion of the model surface on which the electrodeposited film is to be formed and having abrasive grains on at least the surface portion. Electrodeposition processing method.