JPS6130328A - Method and device for mirror surface like polishing stainless steel - Google Patents

Abstract

PURPOSE:To reduce the cost of production of a stainless steel base plate, by performing combined electrolytic polishing on the plate at polishing pressure and electrolyzing electrical current density below prescribed values while impregnating a polishing soft porous synthetic resin with a polishing electrolyte made of a solution of a neutral salt and mixed with polishing abrasive grains. CONSTITUTION:An electrolyte is impregnated into a polishing material 3 such as foamed polyurethane and foamed polyester as the material is pushed on a stainless steel plate 4 and electricity is applied between the plate and an electrode 5 to electrolytically polish the plate. At the same time, the polishing material 3 is slid relative to the plate 4 to polish it by abrasive grains. The density of electrical current for the electrolytic polishing and the pressure for the polishing by the material 3 are set at 0.5A/cm<2> or less and 0.02kg/cm<2> or less, respectively, to prevent the great consumption of the polishing material 3 and the abrasive grains to reduce the cost of the polishing. Since the electrolyte is impregnated into the polishing material 3 to bring the electrolyte into good contact with the base plate 4, the performance of the polishing is high enough to enable desired polishing even if the polishing pressure and the electrolyzing current density are made low.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method and apparatus for mirror polishing stainless steel used for solar cell substrates and the like (by electrolytic composite polishing).

(Prior Art) Stainless steel is widely known to be excellent in durability, heat resistance, and electrical conductivity, and to be relatively inexpensive. For this reason, it has recently begun to attract attention as an application for solar cell substrates and the like.

However, stainless steel has surface defects such as minute protrusions, and if used as is, the yield will be reduced. Therefore, in order to use stainless steel for solar cell substrates and the like, it is necessary to polish the surface in advance to remove these fine protrusions and smooth the surface.

Electrolytic composite polishing is an effective polishing method for smoothing surfaces. This polishing method is a method in which an electric current is passed between an electrode and stainless steel in an electrolytic solution containing abrasive grains to perform a combination of electrolytic polishing and polishing using abrasive grains.

(Problem that the invention is trying to solve) However, conventional electrolytic composite polishing requires high polishing pressure (for example, 0.1 to 0.3 Y/,...
2) and high current density (1.0 to 10 A/an2). For this reason, the polishing abrasive grains and abrasive material are consumed to a large extent, and the equipment costs are high, resulting in high polishing costs.

(Means for Solving the Problems) The present invention has been made to solve the above-mentioned drawbacks.
The aim is to achieve mirror polishing of stainless steel by using a soft porous synthetic resin as the abrasive material, which enables electrolytic composite polishing at low polishing pressure and low current density, thereby reducing board manufacturing costs. The present invention aims to provide a method and an apparatus for the same.

The present invention will be explained in detail below.

The method of the present invention uses a polishing electrolyte in which polishing abrasive grains are mixed in a neutral salt solution when performing electrolytic composite polishing of a stainless steel substrate material, and impregnates an abrasive material made of a soft porous synthetic resin with this electrolyte. Seshimegaraken 1-8 pressure 0.02 kg/
cm2 or less, and electrolytic composite polishing is performed at an electrolytic current density of 0.5 A/cm" or less.

In this method, it is preferable that the surface of the stainless steel to be polished be as smooth as possible, for example, the surface roughness is 0.3 μm.
Below Rrr1. Stainless steel that has been brightly annealed and temper rolled with a small x is used. The polishing electrolyte is, for example, NaN
It is a solution of about 10% to 30% of a less corrosive neutral salt such as O3 or NaN0□. The abrasive grains contained in this electrolytic solution are preferably made of alumina chromium oxide or the like and have a particle size of about 0.05 to 1.0 μm, and are usually mixed in 10 to 50 1/l.

The material of the soft porous synthetic resin abrasive is foamed polyurethane, foamed polyester, foamed polyethylene, etc., and the pores are open-celled.

In the present invention, an abrasive material is pressed against the stainless steel substrate material and an electrolytic solution is caused to flow therethrough, thereby impregnating the abrasive material with the electrolytic solution. Then, electricity is passed between the electrode and the substrate material to perform electrolytic polishing. At the same time, the abrasive material is slid relative to the substrate material to perform polishing with the abrasive grains. In such polishing, the electrolytic current density was lower than 0.5 A/crn2J''J,
The polishing pressure is 0.02 klil/cn12 or less.

The reason for this is that high polishing pressure and high current density result in increased consumption of the abrasive material or abrasive grains, as described in the disadvantages of the conventional method. According to the present invention, the abrasive material is impregnated with an electrolytic solution and good contact is made between the electrolytic solution and the substrate material, so the polishing performance is high and the desired low polishing pressure and current density are achieved. Abrasive properties can be obtained. Note that the abrasive grain rubbing speed is preferably in/sec or more in order to improve the abrasive grain polishing performance.

Next, a mirror polishing apparatus for manufacturing solar cell substrates will be described with reference to illustrated embodiments.

In the apparatus shown in FIGS. 1 and 2, a substrate material support 2 is disposed within an electrolytic polishing tank 1. As shown in FIG. A disc-shaped soft porous synthetic resin abrasive material 3 is placed above the support base 2. This abrasive material 3 presses against the stainless steel substrate 4 on the support base 2 with a predetermined pressure, and slides and rotates. This abrasive material 3
A disc-shaped electrode plate (cathode) 5 is provided on the upper part of the electrode plate 5, and radial electrolyte supply grooves 5& are formed in the electrode plate 5 as shown by broken lines in FIG. This electrode plate 5 and the abrasive material 3 are held insulated so as to be surrounded by a holder 6. This holder 6 has a rotating shaft 7 fixed at the center of its upper part. A liquid path 7a is formed inside the rotating shaft 7 and communicates with the electrolyte supply groove 5a. This rotating shaft 7 is rotated and reciprocated in the direction of the arrow by a drive device (not shown). Further, a power supply brush 8 is in electrical contact with the rotating shaft 7.
Electric power is supplied between the electrode plate 5 and the substrate material 4 which are in contact with the rotating shaft 7. Furthermore, this apparatus includes an electrolytic polishing tank 1. Liquid path 7n in electrolyte tank 91 rotating shaft 2.

The electrolyte supply groove 5a of the electrode material 5 and the abrasive material 3 are
A polishing electrolyte supply device for circulating the polishing electrolyte is provided.

In this device, an electrolytic solution mixed with abrasive grains is fed by a pump 10 from a liquid path 2a at a rate of, for example, 0.51/min to 5/min, through an electrolytic solution supply groove 5a, and is kept constant in the abrasive material 3. After holding the polishing material for a certain period of time, it is discharged into the electrolytic polishing tank 1 from between the abrasive material 3 and the substrate material 4. At the same time, apply the abrasive material 3 to the substrate material 4.
The material is slid and rotated and reciprocated while being pressed against the surface, and the abrasive grains in the electrolyte abrade the material.

Furthermore, at the same time, an electric current is applied between the electrode plate 5 and the substrate material 4, with the substrate material 4 used as an anode, to perform electrolytic polishing. This polishing time varies depending on the surface condition of the substrate material 40, but is usually 1 dm.
The polishing speed is several tens of seconds to several minutes per polishing process.Also, the polishing speed may be increased by stacking several stages of this apparatus.

Figures 3 and 4 show another device. In this apparatus, a polishing electrolyte containing polishing abrasive grains is placed in an electrolytic polishing tank 11, and a substrate material support stand 12 is placed in this liquid. The support base 12 has a recess 12m having an arcuate cross section on its upper surface, on which a part of the belt-shaped stainless steel substrate material 14 is placed. A cylindrical rotating electrode 15 is arranged above the support base 12, and the outer peripheral surface of the electrode 15 is coated with a soft porous synthetic resin abrasive material 13. The lower part of this abrasive material 13d is in the polishing electrolyte, has the same radius of curvature as the four parts 12a of the support base, and faces the recess 12* of the support base 12. On the other hand, a driving body (not shown) is connected to the electrode 15 so that the electrode 15 and the abrasive material 13 covering it are slidably rotated and reciprocated relative to the substrate material 14. Further, a power supply brush 18 is in electrical contact with the electrode 15, and the electrode 15 and the substrate material 14 are connected to each other.
It forms part of the power supply device that supplies power between the Note that the insulating holder 11m denoted by 16 in the figure is a cylindrical cover.

In this device, in an electrolytic solution mixed with abrasive grains,
The abrasive material 13 is pressed against the substrate material 14 holding the electrolytic solution, and the electrode 15 and the substrate material 14 are simultaneously rotated and reciprocated.
Electrolytic composite polishing is performed by passing a current between the electrode 15 and the electrode 15 as an anode. In this apparatus, since the substrate material 14 is curved in an arc shape, the polishing area can be expanded.

Figures 5 and 6 show further different devices of the invention.

In this apparatus, a substrate material support 22 is arranged in an electrolytic polishing tank 21, and a belt-shaped stainless steel substrate material 24 is placed on the support 22. Above the support stand 22 are a pair of cylindrical rotating electrodes 25□, 25. is arranged, and a soft porous synthetic resin abrasive material 23. is disposed on its outer peripheral surface. .

232 is coated. Each abrasive material 231.

23 and 23 have their lower portions facing above the support stand 22, so that the substrate material 24 on the support stand 22 can be suppressed. In addition, each abrasive material 23, . 232 has opposing sides in contact with each other. Above electrode 2
5□, 252 are rotated in the direction of the arrow shown in FIG. 6 and reciprocated in the direction of the arrow shown in FIG. 7 by a Lus moving body (not shown).
1.25. The rotation and reciprocation of the abrasive material 23. ．． 2.
'4. rotates and reciprocates while sliding on the substrate material 24.

Above the substrate material 24, a pair of nozzles 30th1.
3θh is provided. These nozzles so&1. so
t, is the substrate material 24 and the abrasive material'? A polishing electrolyte containing polishing abrasive grains is spouted between the polishing electrolyte tank 21.J1+231 and the polishing electrolyte tank 21. Electrolyte tank 29 and the above nozzle? Oa, . It constitutes a part of a power supply device that supplies power to the
L is a cylindrical cover.

In this device, an electrolytic solution mixed with abrasive grains is passed through a nozzle 30.
Each abrasive material 231 from m1, 30a2.

23, and the abrasive material 23, . 2
: While pushing the substrate material 24 with 9□, it slides and rotates and slides back and forth, and at the same time the electrodes 25, . 25. and substrate material 24
Electrolytic composite polishing is performed by passing a current between the substrate material 24 and the substrate material 24 as an anode.

According to this device, a pair of abrasive materials 231.

Since 23□ is used, the polishing area of the substrate material 24 can be increased, the polishing liquid can be used effectively, and the polishing efficiency can be increased.

7 to 9 show another device. This device is
A substrate material support stand 32 is disposed within the electrolytic polishing tank 31, and a stainless steel substrate plate 34 is placed thereon.

A soft porous synthetic resin abrasive material 33 is placed above the support base 32 to face the support base 32 and presses the substrate material 34 . An electrode plate 35 (cathode) is placed above the abrasive material 33.
are provided, and this electrode plate 35d electrolyte flow hole 35a...
* is formed in communication with the abrasive material 33. A flat polishing plate 41 is provided on the top of the electrode plate 35, and this polishing plate 41
The electrolyte flow holes 41a... are connected to the electrolyte flow holes 40.
It is formed in communication with h... These abrasive materials33.
The electrode plate 35 and the polishing plate 41 are integrally insulated and held by an insulating holder 36, and the insulating holder 26 prevents leakage current and retains the polishing liquid in the abrasive material. A slide bearing 4 is mounted on the top of the polishing plate 40.
2... is installed, and this slide bearing 42.
The guide shafts 43 and 43 are inserted into... Then, the abrasive plate 40 is guided by a driving body (not shown). , 43 to move back and forth. Further, an electrolytic solution supply device is incorporated in this device, and the electrolytic solution is pumped into the stain removal polishing tank 3, the electrolytic solution tank 39. Electrolyte flow hole 41a of polishing plate 41, electrode 35
The electrolyte solution is circulated through the abrasive material 33 and the electrolyte flow hole 35m. Furthermore, a power supply device is incorporated to pass a current between the electrode 35 and the substrate material 34. In this device, an electrolytic composite polishing solution mixed with abrasive grains is passed through the electrolyte distribution holes 41a, , ? It is put into the abrasive material 33 from a distance of 5 m, held for a predetermined period of time, and then discharged into the electrolytic polishing tank 31. At this time, the abrasive material 33 holding the electrolyte is transferred to the substrate material 3.
4, and at the same time, a current is applied between the plate 35 and the substrate material 34, with the substrate material 34 used as an anode, to perform electrolytic composite polishing.

(Example) Next, examples of the present invention will be described.

Electrolytic composite polishing was performed using the apparatus shown in FIGS. 1 and 2 under the following conditions.

Electrolytic composite polishing conditions Substrate material Width 300mm, thickness 0.3m Surface roughness R,
0.26μm Material Bright annealed and temper rolled stainless steel abrasive Soft porous synthetic resin (foamed polyurethane) Polishing pressure 0.0051ψ/Crn2 Electrolyte Composition Nitric acid) IJ 1,20011/
i Polishing abrasive grain Material Chromium oxide Particle size 0.58m
Mixing ratio 20 El/l! Electrolytic current density 0.2A, 7cm" Abrasive grain rubbing speed 2m/see Polishing time 60 seconds/ldm" After polishing under the above-mentioned polishing conditions, the surface roughness of the substrate material surface was measured and was extremely smooth with R of 0.06μm. It was amazing.

Similarly, using the devices shown in FIGS. 3 and 4, the devices shown in FIGS. 5 and 6, and the devices shown in FIGS. 7 to 9,
Electrolytic composite polishing was performed under the same polishing conditions. As a result, the surface of the substrate material became extremely smooth, similar to the previous example.

(Effects of the Invention) As described in detail above, according to the present invention, electrolytic composite polishing is performed in a state where the soft porous synthetic resin abrasive is impregnated with an electrolytic solution. , it is possible to prevent consumption of abrasive materials and abrasive grains, and reduce polishing costs.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of the device of the present invention, and FIG.
FIG. 3 is a cross-sectional view showing another example of the device of the present invention, FIG. 4 is a cross-sectional view taken along line ■-IV in FIG. 3, and FIG. A cross-sectional view showing an example of a further different device of the present invention; FIG. 6 is a cross-sectional view taken along line ■-■ in FIG.
FIG. 7 is a sectional view showing another example of the apparatus of the present invention, FIG. 8 is a sectional view of the abrasive plate, electrode, and abrasive material of the same apparatus, and FIG. 9 is a plan view of the same apparatus. 1.11, 21, 31... Electrolytic polishing tank, 11a. 21a...-cylindrical cover, 2, 12, 22,
32-... Substrate material support stand, 12a... Arc-shaped recess in cross section, 3°13.23□, 23□, 33... Soft porous synthetic resin abrasive material, 4, 14, 24, 34... Stainless steel substrate material, 5,35...electrode plate, 15,251°2
5. Rotating electrode, 5a... Electrolyte supply groove, 35a
... Electrolyte flow hole, 6, 16, 261. ? 6.
...Insulation holder, 7...Rotating shaft, 7a...Liquid path, I
I, 18°28... Power supply brush, 9,29.39...
・Electrolyte tank, 10, ,? 0 , 40 , , Pump, 30a1, 301L2... Nozzle, 41... Grinding plate, 41a... Constant, f @ liquid flow hole, 42... Sly P bearing, 43... Guide shaft.

Claims (5)

[Claims] (1) When electrolytically composite polishing a stainless steel substrate material, an abrasive material made of soft porous synthetic resin is impregnated with a polishing electrolyte containing abrasive grains mixed in a neutral salt solution, and a polishing pressure of 0.02 kg is applied. /cm^2 or less, electrolytic current density 0.
A method for mirror polishing stainless steel, characterized by electrolytic composite polishing at 5 A/cm^2 or less. (2) An electrolytic polishing tank, a substrate material support placed in the electrolytic polishing tank, a soft porous synthetic resin abrasive placed oppositely above the support, and an upper part of the abrasive. An electrode plate provided with an electrolyte supply groove, a holder for insulating and holding the electrode plate and the abrasive material, and a stainless steel substrate material on which the abrasive material is placed on the support base by rotationally driving the holder. a driving body configured to rotate while sliding against the electrode plate; a supply device that supplies a polishing electrolyte containing abrasive grains to the substrate material from the electrolyte supply groove of the electrode plate through the abrasive material; A stainless steel mirror polishing device comprising a power supply device that supplies power between an electrode plate and the substrate material. (3) An electrolytic polishing tank containing a polishing electrolyte containing polishing abrasive grains, a substrate material support placed within the electrolytic polishing tank and having a concave portion with an arcuate cross section on its upper surface, and an electrolytic polishing tank placed above the support. a cylindrical rotating electrode; a soft porous synthetic resin abrasive material coated on the outer circumferential surface of the electrode and whose lower part faces the recess of the support base; A mirror polishing apparatus for stainless steel, comprising: a driving body that rotates while sliding against an upper stainless steel substrate; and a power supply device that supplies power between the electrode and the substrate. (4) An electrolytic polishing tank, a substrate material support placed in the electrolytic polishing tank, a pair of cylindrical rotating electrodes placed above the support, and A soft porous synthetic resin abrasive material whose lower part faces the support base, and the rotary electrode are rotationally driven so that the abrasive material rotates while sliding against the stainless steel substrate material located on the support base. a drive body made of a metal powder, a nozzle that spouts a polishing electrolyte containing abrasive grains between the abrasive material and the substrate material, and a power supply device that supplies power between the rotating electrode and the substrate material. Stainless steel mirror polishing equipment. (5) An electrolytic polishing tank, a substrate material support placed in the electrolytic polishing tank, a soft porous synthetic resin abrasive placed oppositely above the support, and an upper part of the abrasive. an electrode plate provided with an electrolyte flow hole formed therein; an abrasive plate provided on the upper part of the electrode plate and formed with an electrolyte flow hole; a holder for insulating and holding the abrasive material, the electrode plate, and the abrasive plate; A driving body that reciprocates the abrasive plate so that the abrasive material slides and reciprocates against the stainless steel substrate material placed on the support base; a supply device that supplies the substrate material through the electrolyte distribution hole of the electrode plate, the electrolyte distribution hole of the electrode plate, and the abrasive material, and a power supply device that supplies power between the electrode plate and the substrate material. Stainless steel mirror polishing equipment.