JP6804086B2 - Electrolytic processing equipment and method - Google Patents

Description

The present invention relates to an electrolytic treatment, and more particularly to an apparatus and method relating to the circulation of an electrolytic solution for electrolytic polishing or electroplating.

A linear collider is about to be constructed as a device to form the Big Bang state (ILC project). As shown in FIG. 5, a niobium hollow tube 100 having flanges 101a and 101b at both ends and whose diameter changes periodically in the axial direction is used for the linear collider. One of the factors for obtaining a predetermined effect in this experiment is whether or not the inner surface of the niobium cavity tube 100 is smooth.

However, since the hollow tube 100 is subjected to excessive pressure or heat during molding, the structure on the inner surface thereof is in a non-uniformly distorted state. If this surface state is left as it is, the electrical and magnetic properties will also be non-uniform, and as a result, it will not be possible to give a predetermined velocity to electrons and protons. Therefore, a method of polishing the inner surface of the hollow tube to a predetermined thickness has been developed.

Chemical polishing and electrolytic polishing are generally used as methods for polishing hollow tubes as described above, not limited to niobium, but electrolytic polishing will be described here.

When the inner surface of a hollow tube, particularly a hollow tube having a complicated shape rather than a straight inner surface, is electropolished as described above, it is important to treat air bubbles generated from the polishing liquid. That is, when air bubbles stay, the surface of the portion becomes rough, and the state is not satisfactory.

Japanese Patent Application Laid-Open No. 61-23799 discloses an apparatus for polishing the inner surface of a hollow tube (metal hollow body) having a bulge in the central portion in the longitudinal direction of the tube. That is, with the longitudinal direction of the hollow pipe held horizontally, the liquid passing pipe is passed through the center of the metal hollow body, and the electrolytic solution is supplied to the bulge from one end of the liquid passing pipe. The polishing liquid is supplied so that substantially the lower half of the inside is immersed in the polishing liquid while rotating the hollow body with respect to the central axis of the hollow body. Here, the electrolytic solution is supplied from one of the supply pipes passed through the center of the hollow body from a supply port provided at a position corresponding to the bulge of the hollow body under the liquid supply pipe, and the other opening of the hollow body is opened. It is configured to be pulled out from the part. Therefore, the state of the flow of the electrolytic solution supplied to the swollen part differs depending on the part, and the polishing state becomes non-uniform.

In Japanese Patent Application Laid-Open No. 11-350200, in order to improve the above-mentioned drawbacks, the electrolytic solution is supplied vertically upward from the upper side of the liquid supply pipe so that the flow of the electrolytic solution is not generated in the bulge, and the polishing state is obtained. Is trying to be uniform.

However, when the hollow tube is arranged horizontally as described above, the upper half is not immersed in the electrolytic solution, and the surface roughness due to the bubbles generated by the electrolysis cannot be ignored. Therefore, in Patent 5807938, the applicant of the present application discloses an apparatus in which the shaft of the hollow tube is vertically arranged and electrolytic treatment (polishing, plating) is performed in a state where the entire inner surface of the hollow tube is immersed in the electrolytic solution. ..

JP-A-61-23799 JP-A-11-350200 Japanese Patent No. 5807938

In the above patent 5807938, the hollow tube is made vertical, and the electrolytic solution is filled in the entire inside of the hollow tube for processing. In addition, the blade electrodes that follow the internal shape of the hollow tube are rotated inside the hollow tube for electrolytic polishing. In this configuration, the air bubbles escape above the hollow tube, so that the surface roughness due to the air bubbles is improved to a considerable extent. However, although most of the generated bubbles escape upward as expected, there is also a nearly horizontal part in the bulge of the hollow tube, and in this part the flow of bubbles slows down and accumulates. As a result, surface roughness will occur.

The present invention has been proposed in view of the above-mentioned conventional circumstances, and an object of the present invention is to provide an electrolytic treatment method and an apparatus capable of performing electrolytic polishing while suppressing surface roughness due to bubbles regardless of the shape of a hollow tube. ..

The present invention includes the following electrodes, a supply pump, a first valve mechanism, a return pump, a second valve mechanism, a liquid flow control means, and an electrolytic control means.

An electrode having an outer shape that follows the internal shape of the hollow tube is inserted into the hollow tube arranged in the vertical direction. The liquid flow control means supplies the electrolytic solution from one of the hollow pipes to the hollow pipe for a first predetermined time by the supply pump and the first valve mechanism, and by the return pump and the second valve mechanism, the other of the hollow pipes. The electrolytic solution is pulled out from the hollow tube to return the electrolytic solution to the liquid tank, and then the electrolytic solution is supplied from the other side of the hollow tube for a first predetermined time with a second pause time, and the one side of the hollow tube is supplied. The electrolyte is withdrawn from. Further, the electrolytic treatment means applies a voltage required for electrolytic polishing between the hollow tube and the electrode while the electrolytic solution is being supplied to the hollow tube.

The hollow tube may be a niobium tube having a periodic bulge.

With the above configuration, the period during which the electrolytic solution flows in the cavity tube from bottom to top and the period during which it flows from top to bottom are alternately alternated, so that the generated bubbles do not stay in one place. Therefore, the polished state of the inner surface of the hollow tube is less affected by the generated bubbles, and the surface roughness can be suppressed.

The figure which shows the outline of this invention. The schematic which shows the control system of this invention. The figure which shows the electrode in the case of one bulge part used in this invention. The figure which shows the electrode in the case of a plurality of bulges used in the present invention. The figure which shows the example of the hollow tube.

<Reflux mechanism>
FIG. 1 is a diagram showing an electrolytic polishing system for a hollow tube to which the present application is applied. A hollow tube having a plurality of bulging portions shown in FIG. 5 is vertically installed, and an electrolytic solution is supplied as described below. FIG. 2 is a schematic view showing the control mechanism of the present invention.

As described below, the valve mechanism includes a supply valve mechanism 210 that supplies the electrolytic solution to the hollow tube 100, and a return valve mechanism 220 that drains the electrolytic solution from the hollow tube 100.

As shown in FIGS. 1 and 5, the actual hollow tube 100 has a plurality of bulges periodically in the axial direction, but in FIG. 2, the bulge is represented by one.

Supply / discharge ports 110a and 110b are provided on the lower and upper sides of the hollow pipe 100 arranged in the vertical direction, and in addition, a supply pump 120a and a return pump 120b are provided.

The upper and lower supply / discharge ports 110a and 110b are connected to the supply pump 120a via the supply valve mechanism 210, and the supply pump 120a is connected to the electrolytic solution tank 300. Further, the upper and lower supply / discharge ports 110a and 110b are connected to the return pump 120b via the return valve mechanism 220, and the return pump 120b is naturally connected to the electrolytic solution tank 300.

The open / closed state of the supply valve mechanism 210 and the return valve mechanism 220 is controlled by the liquid flow control device 400 as follows, and at the same time, the electrolysis control is performed by the electrolysis control device 500.

First, the cavity 20 is equipped with the electrode 20 described below. With the electrode 20 mounted, the liquid flow control device 400 opens the supply valve mechanism 210 to the upper supply / discharge port 110a side, closes it to the lower supply / discharge port 110b side, and closes the return valve mechanism 220. It is closed on the upper supply / discharge port 110a side and open on the lower supply / discharge port 110b side. In this state, the electrolytic solution is filled from the liquid tank 300 for a predetermined time, for example, 10 minutes from above the hollow pipe 100, and is controlled to be drained from the lower supply / discharge port 110b. At the same time, the electrolytic control means 500 applies a positive voltage to the hollow tube 100 side and a negative voltage to the electrode side to electrolytically polish the inner surface of the hollow tube 100.

Then, when the predetermined time elapses, the supply of the liquid and the electrolytic polishing are stopped for another predetermined time (for example, 1 minute). Next, the liquid flow control device 400 opens the supply valve mechanism 210 to the lower supply / discharge port 110b side, closes it to the upper supply / discharge port 110b side, and closes the return valve mechanism 220 to the upper supply / discharge port 110a side. It is opened and closed on the lower supply / discharge port 110b side. In this state, the electrolytic solution is flowed from the bottom to the top for the predetermined time, and the voltage required for electrolytic polishing is applied by the electrolytic control device.

Then, after another predetermined time of rest, the process returns to the initial state of supplying the electrolytic solution from above again. The liquid flow control device 400 and the electrolytic control device 500 will control to maintain this cycle.

By controlling as described above, bubbles generated while the electrolytic solution is flowing to one side (for example, from top to bottom) and accumulated in a part of the cavity tube 100 are electropolished in the next step (from bottom to top). In the process of flowing the liquid), it is possible to avoid being swept away by the electrolytic solution having the opposite flow direction, which adversely affects the polishing state.

<Electrode>
In order to electropolish the inner surface of the hollow tube 100, it is necessary to insert an electrode inside the hollow tube 100. FIG. 3 shows a perspective view of the electrode 20 used in the present invention, and more details are disclosed in Japanese Patent Application Laid-Open No. 5807938.

The electrode shaft 21 has a base end having a predetermined width in the axial direction and an outer peripheral end having a shape corresponding to the inner surface shape of the bulging portion of the hollow tube 100 of the object to be polished, and at least the outer peripheral end is made of metal. One or a plurality of single blades 22a, 22b ... Made of thin plates (two in the figure) are arranged at equal intervals in the circumferential direction to form the blade electrodes 22.

Each single blade 22a, 22b ... Constituting the blade electrode 22 has flexibility and has a minimum diameter when wound around the electrode shaft 21, and in this state, is concentric with the electrode shaft 21. It is designed to be stored in the arranged storage cylinder 29. Axial slit groups 23 (23a, 23b ...) Are provided at positions corresponding to the tips of the single blades 22a, 22b ... Stored in the storage cylinder 29, and each of the slit groups constituting the storage cylinder 29 is provided. The tips of the single blades 22a, 22b ... Are inserted into the slits 23a, 23b ... To the extent that they slightly protrude to the outside of the storage cylinder 29. As a result, by rotating the electrode shaft 21 and the storage cylinder 29 relatively, the tips of the single blades 22a, 22b ... Can be inserted and removed in the radial direction, and the tips of the single blades 22a, 22b ... (Diameter adjusting means: electrode shaft 21 + blade electrode 22 + storage cylinder 29 + slit group 23).

As a configuration in which the storage cylinders 29 are concentrically arranged on the electrode shaft 21, for example, a spacer 30 having a diameter larger than that of the electrode shaft 21 and matching the diameter of the storage cylinder 29 may be fitted to the electrode shaft 21. Conceivable.

Further, each single blade 22a, 22b ... Is covered with a mesh made of synthetic resin (for example, a stitch of 1 μm or less).

As described above, the blade electrode 22 takes two modes, a retracted state and an operating state. That is, in the stored state (not shown), the tips of the single blades 22a, 22b ... Slightly protrude from the slits 23a, 23b ... Of the storage cylinder 29. In this state, the electrode is attached to or detached from the hollow tube 100. Further, as shown in FIG. 3, in the operating state, the electrode shaft 21 and the storage cylinder 29 are relatively rotated, and the outer peripheral ends of the single blades 22a, 22b ... Are pushed out near the inner peripheral surface of the hollow tube 100. (The distance between the outer peripheral end of each single blade 22a, 22b ... And the inner peripheral surface of the hollow tube 100 is, for example, about 1 cm).

FIG. 3 shows a case where there is one bulge, but when there are a plurality of bulges, the shape is as shown in FIG.

<Electropolishing>
In the ordinary hollow tube shown in FIGS. 1 and 2, the position where the surface roughness is the largest is the upper shoulder portion of the bulging portion. Therefore, using the electrode 20, the electrolytic solution is supplied from the lower supply / discharge port 110b for 15 minutes (suction from the upper supply / discharge port), stopped for 1 minute, and then the electrolytic solution is supplied from the upper supply / discharge port 110a for 15 minutes ( The surface roughness of the above-mentioned position when sucked from the lower air supply / discharge port was about 0.3 μm, and the surface roughness of other portions (for example, the lower shoulder portion of the bulge) was also the same. On the other hand, in the experiment using the rod-shaped electrode, the surface roughness of the upper shoulder portion was as high as 3 μm, and that of the other portion was 0.5 μm or less.

It can be understood that the method according to the system of the present application is excellent.

As described above, when the hollow tube is electrolytically polished using the apparatus according to the present invention, the surface roughness of the portion susceptible to the effects of air bubbles generated during polishing is the same as that of the other portions, for example, in a linear collider. When the inner surface of the hollow tube to be used is polished by the device, high performance can be obtained magnetically and electrically.

20 Electrode 21 Electrode shaft 22 Wing electrode 22a, 22b Single wing 29 Storage cylinder 23 (23a, 23b ...) Slit group 100 Cavity pipe 210 Supply valve mechanism 220 Return valve mechanism 110a, 110b Supply / discharge port 120a Supply pump 120b Return pump 300 Electrode tan 400 Liquid flow control device 500 Electrode control means

Claims (4)

Electrodes inserted in the hollow tubes arranged in the vertical direction,
A supply pump that supplies the electrolyte to the hollow tube,
A return pump that returns the electrolyte from the hollow tube to the liquid tank,
A first valve mechanism for forming a circuit for supplying an electrolytic solution from one of the hollow tubes by the supply pump,
A second valve mechanism that forms a circuit that draws the electrolytic solution from the other side of the hollow tube by the return pump.
The electrolytic solution is supplied from one of the hollow tubes, and the electrolytic solution is pulled out from the other of the hollow tubes and returned to the liquid tank for a first predetermined time, and then paused for a second predetermined time. After that, the liquid flow control means for controlling the cycle in which the electrolytic solution from the other side of the hollow tube is supplied and the state in which the electrolytic solution is pulled out from one of the hollow tubes and returned to the liquid tank is continued for the first predetermined time. ,
Electrolytic treatment provided with an electrolytic control means for applying a voltage and a current required for electrolytic polishing between the electrode and the cavity tube during the first predetermined time and suspending the application of the voltage for a second predetermined time. apparatus. The electrolytic treatment apparatus according to claim 1, wherein the hollow tube is a niobium tube having a periodic bulge. The electrodes are a state in which a wing electrode having a plurality of single blades having a shape along the inner surface of a hollow tube is wound around an electrode shaft and a state in which the winding is unwound and extended in the circumferential direction. The electrolytic processing apparatus according to claim 1 or 2, wherein the voltage and the current are applied in the operating state. The electrolytic treatment method using the electrolytic treatment apparatus according to claim 1.
The electrolytic solution is supplied from one of the hollow tubes in which the shafts are arranged in the vertical direction, and the electrolytic solution is pulled out from the other of the hollow tubes and returned to the liquid tank for a first predetermined time. The steps to perform electropolishing on the tube,
A step of stopping the supply of the electrolytic solution and the electrolytic polishing for the second predetermined time after the first predetermined time,
After that, the electrolytic solution from the other side of the hollow tube is supplied, and the state of pulling out the electrolytic solution from the one side of the hollow tube and returning it to the liquid tank is continued for the first predetermined time, and during that time, electrolysis to the hollow tube is performed. An electrolytic treatment method with steps to perform polishing.

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