JPS62224522A - Electropolishing method for internal surface of elbow pipe and electrolyte supply cylinder and negative electrode rod drive device - Google Patents

Abstract

PURPOSE:To enable the application of electropolishing to the internal surface of a small bore elbow pipe by inserting in said pipe a negative electrode rod comprising a soft core metal with the external surface thereof wound spirally with a band of soft insulation, and causing said rod to give reciprocating motion. CONSTITUTION:A band 5 of soft insulation such as teflon is wound about the external surface of a core metal 4 of twisted copper wire, thereby forming a negative electrode rod 3. This rod 3 is inserted in an elbow pipe 1, connected to a drive axis 9 and caused to give reciprocating motion within the elbow pipe 1. An electrolyte 6 is drained at the discharge port 19a of the elbow pipe 1 after passing the inlet port 7 of an electrolyte supply cylinder 2 and the outlet port 8 thereof and filling the internal space of the elbow pipe 1. Said band 5 prevents a short circuit between the core metal 4 of the negative electrode rod 3 and said pipe 1 as a positive electrode, and gases generated in an electrolytic process are quickly discharged from the elbow pipe 1 due to the spiral winding of the band 5. Also, the concentration of the electrolyte 6 is kept constant by said reciprocating motion. Consequently, the internal surface of the elbow pipe 1 including the radiused part 1b thereof can be exposed to good electropolishing and the application of the subject method to a small bore elbow pipe becomes feasible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for electropolishing the inner surface of an elbow pipe, and particularly to a method for electrolytically polishing the inner surface of a small diameter elbow pipe such as a stainless steel pipe.

BACKGROUND ART In recent years, especially in the semiconductor industry, which has been rapidly developing, as the scale of semiconductor integration increases, high purity gases used in the manufacturing stage are required, and there is a need to improve the cleanliness of the gases. For this reason, there are strict regulations regarding piping members for transferring and supplying gas, and it is desired to supply products with high cleanliness (clean and smooth) inner surfaces of piping members.

As for this cleanliness, the tube inner surface roughness is 0.3 to 0.61.
Since a quality of about Lm is required, cold working or mechanical polishing is impossible, and electrolytic polishing is adopted.However, for long small diameter pipes, electrolytic polishing methods that achieve high internal quality have already been developed by IJ. It is being done.

However, there are examples of electrolytic polishing being used only for large diameter elbow pipes, and the technology level has not yet been reached to obtain the required internal surface roughness for small diameter elbow pipes. is the current situation.

In general, electrolytic polishing is an electrolytic polishing process in which a metal item to be polished is used as an anode in an electrolytic solution of a strong acid and a strong alkali, and a current is passed through the contact surface between the metal surface and the electrolytic solution. The metal surface is polished to a smooth surface by applying the principle that a large amount of current flows through the thin portion of the viscous film, that is, the convex portions of the metal surface, and the convex portions are preferentially molten.

Regarding the conventional internal electrolytic polishing method for large-diameter elbow pipes, as shown in FIGS. 11 and 12, elbow pipe 101 (7)
A center guide 102 with a hole 102a through which the electrolytic solution communicates to the inside of the tube is attached to both tube ends 101a and 1olb, and while an electrode rod (copper rod) 103 is supported by the center guide 102, the tip 103a of the electrode rod 103 is inserted. Elbow pipe 101
Insert the electrode rod 1 into the tube up to the vicinity of the 7-hole part 101b.
Electrolytic polishing was performed using 03 as a cathode and elbow tube 101 as an anode. In addition, center guide 103
Naturally, it is made of electrically insulating material.

[Problems to be Solved by the Invention] However, in the above-mentioned prior art, the elbow pipe 10
1, the inner surface near the rounded part 101b is noticeably rough, especially in small-diameter elbow pipes (inner diameter: 4.35 to 10.7 mm).
degree), the tube inner surface roughness is 0.3 to 0.61Lm.
It is difficult to obtain a certain degree of quality.

Further, as shown in FIG. 12, the tip 1 of the electrode rod 103
03a is formed into a tapered shape to make the rounded part 1 as close as possible.
A method of inserting the electrode rod 103 near 01b may be adopted, but even this method cannot sufficiently improve rough skin, and the radius of curvature of the rounded portion becomes small, especially in small-diameter elbow pipes, so it is necessary to form the electrode rod 103 in a tapered shape. Almost no effect can be expected compared to the case without this treatment.

On the other hand, in the case of dipping, the entire tube can be immersed in the electrolytic solution and the electrolytic solution is sufficiently supplied by means of electrolytic polishing, but this method has the disadvantage that electrolytic unevenness occurs on the outer surface of the tube. Furthermore, since the electrolyte is not forcibly supplied, there are also drawbacks such as the ability to maintain a constant electrolytic capacity over the length of the pipe.

Therefore, in the present invention, we aim to fundamentally improve the cathode structure and its insertion means, improve the efficiency of the flow state of the electrolyte, and further maintain the viscous membrane formed between the cathode and the electrolyte in an appropriate state at all times during electrolysis. The purpose of this invention was to provide an electrolytic polishing method that allows the gas generated during electrolysis to be quickly released to the outside of the tube, thereby obtaining a polished surface with a high degree of cleanliness over the entire inner surface of the tube, even for small-diameter elbow tubes. It was done.

[Means for Solving the Problems] The present invention consists of three inventions: ``Method for electropolishing the inner surface of an elbow tube,'' ``Electrolyte supply cylinder,'' and ``Cathode rod drive device.''

The "inner surface electrolytic polishing method for elbow tubes" is based on the approximately axial line of an elbow tube whose anode is a cathode rod in which a flexible band made of insulating material is spirally wound around the outer periphery of a flexible core metal. The electrolyte is supplied into the elbow tube, and the cathode rod acts as an elbow.

The "electrolyte supply tube" is an invention used in the invention of the above-mentioned "inner surface electrolytic polishing method of an elbow tube", and includes an electrolyte inlet,
It has an outlet for supplying electrolyte to the mouth of the elbow tube and a through hole for the drive shaft connected to the cathode rod, and has a tapered flow path in which the electrolyte flowing from the inlet is collected at the outlet. It is characterized by the fact that it is formed inside.

The "cathode rod drive device" is also an invention used in the invention of the above-mentioned "inner surface electrolytic polishing method of an elbow tube", and is a movable table that is caused to reciprocate by a first reciprocating mechanism installed on the base. The present invention is characterized in that a second reciprocating mechanism is installed, and a drive shaft connected to the cathode rod is connected to a power transmission section of the second reciprocating mechanism.

The basic configuration of the present invention will be explained below with reference to FIGS. 1 to 3.

Figure 1 shows the electrolyte supply tube 2 to the elbow tube l, which is the object to be polished.
This is a cross-sectional view showing a state in which a cathode rod 3 is attached and a cathode rod 3 is inserted therethrough.

Figure 2 is an enlarged view of the cathode rod 3 (the band is partially broken)
However, the rA pole bar 3 has a structure in which a band 5 made of an insulating material is wound in a ds wire shape around the outer periphery of a flexible core bar 4, and as shown in FIG. It is inserted substantially along the axis of the tube 1 and supported so as to be able to reciprocate along the axis.

This is because the material of the core metal 4 needs to have flexibility and conductivity.

A stranded copper wire or the like is most suitable, and since flexibility is required for the 17 body 5, but insulation is also required, a material such as Teflon is most suitable.

Then, electrolytic polishing is performed using the elbow tube 1 as an anode and the core metal 4 as a cathode, while supplying an electrolytic solution into the tube and moving the cathode rod 3 back and forth approximately along the axis of the elbow tube 1.

By the way, in order to supply the electrolytic solution into the tube, it is desirable to attach an electrolytic solution supply cylinder 2 as shown in FIG. 1.

This electrolyte supply cylinder 2 has an electrolyte inflow lower part and an elbow pipe 1.
Outlet 8. is attached to the tube port 1a of the tube and supplies electrolyte to the tube port 1a. and a through hole 10 for the drive shaft 9 connected to the cathode rod 3, and a tapered flow path 11 is provided therein so that the electrolytic solution 6 flowing in from the inflow lower is gradually concentrated toward the outflow port 8. It is a cylinder formed inside. It is also possible to provide sealing mechanisms 12a and 12b at the joint between the outlet 8 and the pipe port 1a of the elbow pipe 1 and at the sliding portion between the drive shaft 9 and the through hole 10 to prevent the electrolyte 6 from leaking. be.

Further, as the cathode rod driving device, that is, the means for reciprocating the cathode rod 3, it is also possible to employ a single reciprocating mechanism such as a link mechanism or a slider crank mechanism as a general reciprocating mechanism. It is desirable to adopt a two-stage reciprocating mechanism as follows.

That is, as shown in FIG. 3, the first reciprocating mechanism 14 installed on the base 13 causes the reciprocating movement 1. The second reciprocating mechanism 16 has a cathode rod 3 attached to the power transmission section.
T connected to! It is a two-stage reciprocating mechanism with an IA moving shaft 9 attached. Note that any single reciprocating mechanism may be used as the first and second reciprocating mechanisms.

[Operation] According to the "inner surface electrolytic polishing method for elbow pipe" of the present invention, P
The triode rod 3 can be easily inserted into the elbow tube 1 along substantially its axis since both the core metal 4 and the (1'f body 5) are flexible. Even when reciprocating, it is possible to reciprocate while maintaining the radius of curvature corresponding to the rounded portion 1b of the elbow pipe 1.

This reciprocating motion prevents the electrolyte 6 from accumulating near the cathode rod, keeps the concentration of the electrolyte 6 uniform over the entire length of the tube, including the rounded portion 1b, and keeps the electrolytic cooperation constant throughout the tube. Therefore, it is possible to obtain a polished surface with lower roughness even in the rounded portion 1b.

The band 5 includes a core metal 4 which is a cathode and an elbow tube 1 which is an anode.
The electrolyte 6 plays a role of preventing electrical interference due to contact with the core metal 4, and the electrolyte 6 flows smoothly around the core metal 4 due to being spirally wound around the core metal 4. It also plays the role of quickly flushing the gas generated out of the elbow tube 1 to prevent gas bits from being generated on the electrolytically polished surface.

The "electrolyte supply tube" of the present invention smoothes the flow when the electrolyte 6 is forcibly circulated in the elbow tube 1, and the pulsating flow of the electrolyte 6 causes the cathode rod 3 to move into the elbow. tube l
This prevents the band 5 from attaching a contact slit to the inner surface of the elbow pipe 1 by being swung within the elbow pipe 1, and also smoothes the flow within the pipe and prevents the generation of gas bits in the same manner as described above.

That is, the electrolyte 6 flows into the electrolyte supply cylinder z from the inflow lower, but while passing through the tapered flow path 11, the flow at the inflow lower is rectified and concentrated and sent to the outlet 8. ,
This is because a very smooth flow is supplied within the elbow pipe l.

The "near the cathode bar 3" of the present invention provides a reciprocating motion to the cathode bar 3 in order to keep the electrolyte concentration near the cathode bar 3 uniform at all times.

Generally, when driven by a single reciprocating mechanism, 1
When time (T) is plotted on the horizontal axis and stroke (S) is plotted on the vertical axis, the operating state shown by the dotted line 17 in FIG. 4 is shown.
When a two-stage system is used as in the present invention, as shown by the solid line 18 in the figure, the reciprocating motion of a small period is superimposed on the reciprocating motion of a large period, and the electrolyte 6 near the cathode rod 3 is The concentration of the electrolytic solution 6 is kept uniform by fine stirring, and the electrolytic ability is kept constant.

The gas generated near the cathode rod 3 is quickly separated from the cathode rod 3 and discharged to the outside of the elbow tube 1 by the flow of the electrolytic solution 6 in the tube, thereby preventing roughening of the polishing surface caused by the gas bit.

In addition, in FIG. 1, the container indicated by 19 has an elbow pipe l.
This device temporarily stores the electrolytic solution 6 that has passed through the tube and drains it out through the drain nozzle 19a.

[Example] Hereinafter, an example of the present invention will be described using fJSs diagrams to FIG. 7.

FIG. 5 shows an overall overview of the internal electrolytic polishing apparatus for elbow pipes, in which 21 is the elbow pipe to be polished;
Reference numeral 2 denotes an electrolyte supply tube, and 21 and 22 of these have the same structure as that shown in the f:tS1 diagram.

Then, the electrolyte is first stored in the storage tank 23 and placed in the heater 24.
It is maintained at a predetermined temperature by cooling EC25,
The electrolyte supply cylinder 2 is supplied from the storage tank 23 by the circulation pump 26.
The electrolytic solution is sent to the inlet of the tube 22, adjusted to have a smooth flow in the tapered channel inside the tube 22, and sent into the elbow tube 21. The electrolyte that has passed through the elbow tube 21 is temporarily stored in the container 27. While being drained, the liquid is returned to the storage tank 23 through the drain nozzle 27a.

In addition, a cathode rod made of a Teflon band wound in a wire shape around the outer periphery of a stranded copper wire 28 is inserted through the elbow tube 21 along its axis, and the cathode rod A drive shaft 29 is connected to the drive shaft 29, and the drive shaft 29 is extended to the outside of the electrolyte supply cylinder 22 and connected to a power transmission section 30a of a reciprocating mechanism 30 as a cathode rod drive device.

A flexible tension line 31 is connected to the other power transmission section 30b of the reciprocating mechanism 30, and the tension line 31 connects to the pulley 3.
2, it is connected to the copper stranded wire 28 coming out from the container 27 side at the other pipe opening of the elbow pipe 21 while changing the direction, and as a result, the cathode rod - drive shaft 29 - reciprocating N movement mechanism 3 〇-Tensile wire 31-Cathode rod〉 is formed.

Therefore, by driving the reciprocating mechanism 30, the elbow pipe 21
The cathode rod inside will be forced to reciprocate.

During electrolytic polishing, the elbow tube 21 is used as an anode, the copper stranded wire 28 is used as a cathode, and in this case, the drive shaft 29 is made of a conductive material and is connected to the cathode). The electrolyte circulation circuit forces the electrolyte to circulate inside the elbow tube zl while giving reciprocating motion to the cathode rod.

By the way, this reciprocating mechanism 30 is a two-stage reciprocating mechanism consisting of a first reciprocating mechanism 41 and a second reciprocating mechanism 42, as shown in FIG.

The first reciprocating mechanism 41 is installed on a base 43, and is mounted on a disc 45 whose surface is perpendicular to the rotation axis of a motor 44 fixed to the base 43. A short column 47 with an a-tar 46 is erected, and two guide rods 49 are guided by two pairs of bearings 48 installed on a base 43.
Two wooden rods 50 are horizontally suspended between them, and the rotor 46 is sandwiched between the two rods 50 so as to be rotatable.

In addition, FIG. 7 shows the disk 45, rotor 46. FIG. 3 is a plan view showing a retaining portion of the short column 47, the guide rod 49, and the rod 50 to show the relationship therebetween.

The second reciprocating mechanism 42 is mechanically similar to the first reciprocating mechanism 4% IJ41, but its base 5
1 is fixed on the two guide rods 49 of the first reciprocating mechanism 41, and the top and bottom are opposite to the first reciprocating mechanism 41.

That is, the disk 53 is mounted so that its surface is perpendicular to the rotation axis of the motor 5z fixed to the base 51.
A short column 55 with a rotor 54 is erected at the top, and two guide rods 5 are guided by two pairs of bearings 56 installed on a base 51.
Two rods 58 are horizontally suspended between the two rods 58, and the rotor 54 is sandwiched between the two rods 58 so as to be rotatable.

During electropolishing, the motors 44 and 52 are rotated, and the guide rod 57 is driven in such a manner that the reciprocating movements of the guide rods 49 and 57 based on the reciprocating mechanisms 41 and 42 are superimposed. Both ends of the guide rod 57 function as the power transmission parts 30a and 30b to drive the cathode rod back and forth.

In this way, the electrolyte is constantly and smoothly flowing into the elbow tube 21 by the electrolyte supply tube 22, and the cathode rod is inserted through the elbow tube 21 along the approximate axis line due to its flexibility. By finely reciprocating the two-stage reciprocating mechanism 30 while maintaining the same, it is possible to obtain a high-quality electrolytically polished surface with a very high degree of cleanliness even at the 7-1 portion within the elbow pipe 21.

The internal surface electrolytic polishing of a small-diameter elbow pipe was carried out using this embodiment apparatus, and the roughness measurement results were summarized, and the results shown in FIG. 10 were obtained from No. 8 vgi. In each graph, the horizontal axis is the maximum value of roughness (tile m), and the vertical axis is the frequency of the corresponding material. In Figure 8, the inner diameter is 10.7 mm, and in Figure 9, the inner diameter is 7.53 mm. mm, f5I 0 The figure shows the measurement results for a small diameter elbow tube with an inner diameter of 4.35 mm and the number of materials.

As is clear from these results, electrolytic polishing using the apparatus of this embodiment can provide a polished surface with an inner surface roughness of 0.6 pm or less even for a small elbow tube with an inner diameter of about 4.35 to 10.7 mm. It is quite possible.

[Effects of the Invention] Compared to the conventional case where a copper cathode rod is inserted into the tube from the C port of the elbow tube to perform electrolytic polishing,
A flexible cathode rod that is prevented from electrically shorting with the inner surface of the elbow tube is inserted into the tube, and the cathode rod is moved approximately along the axis of the elbow tube while supplying electrolyte into the elbow tube. This makes it possible to obtain an extremely clean internal polished surface even for the rounded portion of the elbow pipe.

Furthermore, the electrolyte supply tube of the present invention enables smooth supply of electrolyte into the elbow tube.

This made it possible for cathode rod contact pickpockets and gas bits to occur.

Furthermore, the reciprocating drive device for the cathode rod of the present invention makes it possible to drive the P3 electrode rod more precisely, stirring the electrolyte near the cathode rod to keep the electrolytic capacity constant at all times, and reducing the amount of electrolyte generated near the cathode rod. This makes it easy to release the gas outside the elbow tube by the flow of electrolyte, thereby preventing the generation of gas bits and making it possible to obtain a high-quality internal polished surface.

[Brief explanation of drawings]

Figures 1 to 3 are diagrams showing the basic concept of the present invention, and Figure 1 shows a state in which an electrolyte supply cylinder is attached to an elbow pipe to be polished, and a cathode rod is inserted through it. 2 is an enlarged view of the cathode rod (partially broken of the band), FIG. 3 is a conceptual diagram of the cathode rod drive device, and FIG. 4 is with time (T) on the horizontal axis. A diagram showing the operating state of the cathode rod drive device with the stroke (S) as the vertical axis, FIG. 5 is an overall overview of the device according to the embodiment of the present invention, FIG. 6 is a front view of the reciprocating mechanism, and FIG. A plan view showing the drive part of the guide rod, FIGS. 8 to 10 are graphs showing the roughness measurement results of internal electrolytic polishing of a small diameter elbow pipe using the apparatus of the embodiment, and FIGS. FIG. 3 is a cross-sectional view showing an electropolishing means for the inner surface of the elbow pipe. 1... Elbow tube 1a... Tube opening 1b... Rounded part 2... Electrolyte supply cylinder 3... Cathode bar 4...
Core metal 5... Band 6... Electrolyte 7... Inlet 8... Outlet 9... Drive shaft lO... Through hole
11...Tapered channel 12a, 12b...Seal mechanism 13...Base 14...Reciprocating mechanism 1
5...Movable base 16...Reciprocating mechanism 17...
Dotted line 18... Solid line 19... Container 19a... Drain nozzle 21... Elbow pipe 22... Electrolyte supply cylinder 23... Storage 4624... Heater 25...
・Cooler 26...Circulation pump 27...Container 2
7a... Drain nozzle 28... Copper stranded wire 29.
... Drive shaft 30 ... Reciprocating mechanism 30a, 30b
...Power transmission section 31...Tension line 32...Pulley 41...First reciprocating mechanism 42...Second reciprocating mechanism 43...Base 44...Motor 45
...Disk 46...Rotor 47...Short column 4
8... Bearing 49... Guide rod 50... Rod 51
... Base 52 ... Motor 53 ... Disc 54
... Rotor 55 ... Short column 56 ... Bearing 57
...Guide rod

Claims (3)

[Claims] (1) A cathode rod, in which a flexible band made of insulating material is linearly wound around the outer periphery of a flexible core metal, is inserted approximately along the axis of the elbow tube, which serves as an anode, and inside the elbow tube. A method for electrolytically polishing the inner surface of an elbow tube, comprising reciprocating a cathode rod roughly along the axis of the elbow tube while supplying an electrolyte to the elbow tube. (2) A cathode rod, in which a flexible band made of insulating material is spirally wound around the outer periphery of a flexible core metal, is inserted through the elbow tube, which serves as an anode, along the approximate axis of the tube. In an electrolytic polishing method for the inner surface of an elbow tube, in which a cathode rod is reciprocated along the axis of the elbow tube while supplying electrolyte into the tube, an inlet for the electrolyte and an outlet for supplying the electrolyte to the mouth of the elbow tube are used. , and a drive shaft through hole connected to the cathode rod,
An electrolytic solution supply tube characterized in that a tapered flow path is formed inside the electrolytic solution flowing from an inlet to an outflow port. (3) A cathode rod, in which a flexible band made of insulating material is spirally wound around the outer periphery of a flexible core metal, is inserted through the elbow tube, which serves as an anode, along the approximate axis of the elbow tube. In a method for electrolytically polishing the inner surface of an elbow tube in which a cathode rod is reciprocated along the approximate axis of the elbow tube while supplying an electrolyte into the tube, a movable table is provided that is reciprocated by a first reciprocating mechanism installed on a base. 1. A cathode rod drive device, characterized in that a second reciprocating mechanism is installed in the cathode rod, and a drive shaft connected to the cathode rod is connected to a power transmission section of the second reciprocating mechanism.