JPH0420726B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrode tool for an electrolytic abrasive composite mirror polishing apparatus which can also be applied to mirror polishing of free-form surfaces.

[Prior Art] Conventionally, electrolytic abrasive composite polishing uses abrasive grains to remove a passive film formed on the surface of a workpiece by electrolysis, thereby mirror-polishing the surface of the workpiece.
It is customary to process rotating surfaces such as flat surfaces and cylindrical surfaces with the electrode tool and workpiece held in a nearly constant posture. It is fixed and an electrode tool is placed opposite to it for polishing.

However, such conventional electrolytic polishing equipment
The machining surface of the electrode tool is generally configured to make sliding contact over a wide area with a specific surface to be polished, such as a flat surface or a cylindrical surface. It is difficult to process the surface with precision, and it cannot be applied to the processing of arbitrarily curved free-form surfaces.

Furthermore, in order to achieve efficient machining, the depth of cut is usually on the order of several micrometers, so the removal amount associated with polishing is relatively large, and a large amount of electrolyte is required in the machining area to eliminate the accompanying electrolytic products. Since it is necessary to provide a stable supply of electrolyte, equipment to pump this electrolyte is required, and the electrode tool facing the workpiece is subjected to a very large reaction force due to the pressure of this electrolyte. , it is necessary to support the reaction force, which inevitably makes the device larger and more complex.

In other words, in conventional electrolytic polishing equipment, the entire machining area of the electrode tool is faced to the workpiece surface, and the current density is set in consideration of machining efficiency, etc. At the same time, the large amount of electrolyte required for this is pumped at high pressure. I have to. Therefore, the reaction force that the tool receives due to the pressure of the electrolyte will reach the order of 100 kg or more, and it must be supported, so the equipment becomes larger and at the same time it becomes difficult to apply it to free-form surfaces. Not only does a large amount of electrolyte flow out to the surrounding area, but it is also impossible to supply electrolyte to the entire processing area.

Further, as described above, when the depth of cut is on the order of several micrometers, a groove with a depth of several micrometers will be formed on the surface of the workpiece after the tool has passed.
Therefore, when polishing the surface of a workpiece having a width larger than the tool diameter, there is a problem that a step is created on the surface depending on the path of the tool, and this step cannot be easily erased.

In this way, it can be said that the conventional electrolytic polishing apparatus has a configuration that is intended only for flat surface polishing and cannot essentially be used for polishing free-form surfaces of arbitrary sizes. In order to apply electrolytic polishing to mirror polishing of free-form surfaces, a polishing technique suitable for that polishing is required.

[Problems to be Solved by the Invention] In order to address the above-mentioned problems, the present inventors, as a result of long-term basic research, have developed a method that has a current density that is significantly lower than that of normal electrolytic processing and uses an extremely small amount of electrolyte. We have discovered that it is possible to perform mirror polishing by removing only the tips of minute protrusions by performing electrolytic abrasive composite polishing using this method, and it is also effective to apply it to polishing free-form surfaces. After confirming this fact, we have come up with the present invention.

Therefore, the technical problem of the present invention is to operate an electrode tool for an electrolytic abrasive composite mirror polishing device with a low current density and a small amount of electrolyte, thereby improving the surface of a workpiece with some unevenness. The present invention is applicable to mirror polishing of arbitrary free-form surfaces, and the polishing can be realized using a simple and compact device.

[Means for Solving the Problems] In order to solve the above problems, in the electrode tool for an electrolytic abrasive composite mirror polishing device of the present invention, the current density is sufficiently lower than that in normal electrolytic machining, and a small amount of electrolyte is supplied. This is an electrode tool for mirror-polishing the surface of a workpiece by using a conductive tool base attached to the tip of the rotating shaft of a rotary drive machine. A back plate forming a reservoir is integrally joined at the periphery, and a contact portion of a sliding contact for power supply and an opening for supplying electrolyte are formed on the back plate of this conductive tool base, so that the contact At the same time, an electrolyte supply pipe is opened to the atmosphere in the electrolyte supply opening, and a large number of electrolyte flows are placed in a position slightly inward from the periphery of the surface plate. A liquid-permeable viscoelastic abrasive body is attached to this surface plate, and the peripheral portion of the viscoelastic abrasive body is processed so that it can hold abrasive grains and deform to follow the surface of the workpiece. We are taking technical measures to make it a surface.

[Function] Electrolyte is supplied from the electrolyte supply pipe through the electrolyte supply opening into the conductive tool base that is open to the atmosphere, and the electrode tool and workpiece are brought into contact with the power supply sliding contact with the tool base. While applying a current between the electrode tool and rotating the electrode tool with the rotary drive machine, the viscoelastic abrasive body or its surrounding area is pressed against the surface of the workpiece, and the surface of the workpiece is Mirror polish.

In this case, the surface of the workpiece is mirror-polished by supplying a sufficiently lower current density than normal electrolytic machining and a small amount of electrolyte solution that can eliminate the electrolytic products. Even if there is some unevenness on the surface of the workpiece, a large amount of electrolyte will not flow out, and the viscoelastic abrasive body deforms to follow the uneven shape, achieving high precision by fitting the abrasive body to the surface of the workpiece. mirror polishing is performed.

In addition, the rotation axis of the electrode tool is tilted with respect to a curved surface that averages out the unevenness on the contact surface between the viscoelastic abrasive body and the surface of the workpiece, and in this state, only the peripheral part of the viscoelastic abrasive body is applied to the workpiece. By performing contact machining, it becomes possible to mirror-finish any free-form surface.

On the other hand, as mentioned above, the electrolyte is not pumped under pressure, but is temporarily stored in the tool base that is open to the atmosphere, and then gradually flows out from the electrolyte supply port, causing viscosity around the electrode tool. It is supplied to the contact area between the elastic polishing body and the workpiece. Therefore, the reaction force due to the back pressure of the electrolyte does not act on the electrode tool, and there is no need for high-pressure pumping of the electrolyte and support for the reaction force, thereby simplifying and downsizing the device. .

[Example] The electrolytic abrasive compound polishing device 10 shown in FIG. A rotating shaft 14, which is rotated by a rotating shaft 14, is led out from the main body 11 of the apparatus, and an electrode tool 20 of the present invention is attached to its tip.

As can be seen from FIGS. 1 and 2, the electrode tool 20 includes a substantially disk-shaped tool base 21 made of conductive copper or other material, and a viscoelastic polishing body 22 attached to the surface of the tool base 21. It is constituted as a subject. The tool base 21 is constructed by integrally joining at the periphery a disk-like surface plate 24 attached to the tip of the rotating shaft 14 and a back plate 25 forming a liquid reservoir 26 around the back surface of the surface plate. The surface plate 24 is provided with a recess 29 in the center thereof into which the head of the screw 28 for attaching to the rotating shaft 14 is inserted, and a number of electrolyte outlet ports located slightly inward from the periphery. 30, and the back plate 25 has a rotating shaft 14 at its center.
An electrolytic solution supply opening 31 is formed between the opening 31 and a sliding contact surface 32 for contacting a power supply sliding contact 33 for supplying electrolysis current, which will be described later, around the opening 31. .

The viscoelastic polishing body 22 attached to the surface of the tool base 21 is made of a sponge-like member such as foamed polyurethane or other synthetic resin foam, or a viscoelastic body with liquid permeability such as nylon nonwoven fabric, It is designed to be attached to the surface of the conductive tool base, and when it is formed of a sponge-like member as shown in the figure, there is a recess 34 inside it.
is formed and adhered to the tool base 21, and the viscoelastic polishing body 22 and the contact plate 3 in contact with the center thereof are formed.
5 and the screw 28 to the rotating shaft 14 together with the tool base 21.
By fixing them with , they can be attached to a rotating shaft. In addition, when using the viscoelastic abrasive body 22 such as a nylon nonwoven fabric, its peripheral portion is adhered to the surface of the tool base 21 or fixed by appropriate means, and then the abutting plate 35 is brought into contact with the rotating shaft 14. It can be fixed with screws 28.

In addition, the viscoelastic polishing body 22 can have abrasive grains dispersed throughout its surface or inside, and in that case, a synthetic resin bond mixed with abrasive grains such as alumina is bonded to a nylon nonwoven fabric or the like. The abrasive grains can be held in an adhesive state, or the abrasive grains in a free state can be supported by the mesh of the nonwoven fabric without fixing the abrasive grains.

A large number of electrolyte outlet ports 30 opened in the surface plate 24 are provided slightly inward from the periphery of the tool base 21 to form an electrolyte reservoir 26 in the inner periphery of the tool base 21 of the electrode tool 20. However, the electrolytic solution is temporarily stored in this liquid reservoir 26 so that the electrolytic solution can be stably supplied from a large number of electrolytic solution outlets 30. Therefore, the electrode tool 20
While the electrode tool rotates, the electrolytic solution sequentially flows out from the electrolytic solution outlet 30, and the electrolytic solution causes contact between the viscoelastic abrasive body 22 and the workpiece around the electrode tool 20 due to the centrifugal force accompanying the rotation of the electrode tool. Supplied to the tangential contact area. Therefore, there is almost no need for equipment to pump the electrolyte, and the electrode tool 20 has excellent electrolyte retention properties, so the electrolyte can be stably delivered not only on horizontal free-form surfaces but also on nearly vertical curved surfaces. Can be supplied and polished.

The electrolyte supply pipe 38 is for supplying electrolyte to the polishing portion around the electrode tool 20, and has a supply port 40 opened at one end of the device main body 11, and the electrolyte is supplied through the device main body to the above-mentioned In the electrolyte supply opening 31 around the rotating shaft 14 provided at the center of the back plate 25 of the tool base 21, there is a discharge port 4 at the other end.
1 is open.

Instead of or in addition to holding abrasive grains in the viscoelastic polishing body 22, this electrolyte supply pipe 3
It is also possible to mix abrasive grains into the electrolytic solution fed through 8.

The power supply terminal 43 at one end of the device main body 11 is for supplying current for electrolysis to the electrode tool 20 through the power supply sliding contact 33 and the sliding contact surface 32 that contacts it, and connects the workpiece to the positive electrode and the electrode. The tool 20 is configured as a negative pole so that they can be connected to a power source (not shown).

In addition, in the figure, 44 indicates a switch operator for rotating the rotary drive machine 12.

The electrolytic abrasive compound polishing device having such a configuration can be used as a portable device by manually lightly pressing it onto an appropriate position on the surface of a workpiece, or by using an automatic device (not shown) equipped with a moving table that can move freely in the X and Y directions in a horizontal plane. It is attached to a feeding device and performs polishing.
As shown in FIG. 3, when polishing a free-form surface on the workpiece 45, while supplying an aqueous solution such as NaNO ₃ or KNO ₃ to the electrode tool 20 through the electrolyte supply pipe 38, the electrode tool 20 and the workpiece are 45
A current of several amperes with a voltage of several volts to 10-odd volts is passed between the electrode tool 20 and
Processing is performed with the peripheral portion of the viscoelastic polishing body 22 in pressure contact with the free-form surface of the workpiece 45.

In this case, with the rotating shaft 14 of the electrode tool 20 tilted with respect to a plane that averages out the unevenness on the contact surface between the viscoelastic polishing body 22 and the workpiece 45,
Machining is performed by bringing only the peripheral part of the viscoelastic abrasive body into contact with the workpiece, but generally the inclination angle of the rotation axis with respect to the contact surface is kept within a range of about 5 to 60 degrees. More preferably, it is effective to maintain the angle in the range of 10 to 45 degrees.

When the electrode tool 20 has a diameter of about 12 cm, the viscoelastic abrasive body 22 can be pressed against the surface of a workpiece having some unevenness at a rotation speed of several hundred rpm or less by the rotary drive machine 12. By deforming the peripheral portion to follow the surface shape of the workpiece and fitting it to the surface, the workpiece can be mirror-polished. In this case, the pressing pressure of the electrode tool 20 against the protrusions on the surface of the workpiece at the contact surface between the viscoelastic polishing body 22 and the workpiece 45 is naturally greater than the pressure against the recesses in the contact surface. The amount removed by abrasive grains or the like increases in the convex portion. However, since it is possible to achieve the same surface roughness for both relatively large concave portions and convex portions, efficient polishing can be performed when shape accuracy is not an issue.

Furthermore, since the electrolytic polishing is performed using an electrolytic solution such as NaNO ₃ or KNO ₃ at a very low current density, a passive film is likely to be formed on the surface of the workpiece. However, on the surface of the workpiece, there is a high probability that minute protrusions will be mechanically polished by the abrasive grains, so the passive film will be removed and electrical activation will increase. The surface roughness of the workpiece is improved.

Such electrolytic abrasive composite polishing can be applied to polishing free-form surfaces of various metal products, and is particularly suitable for polishing the surfaces of stainless steel and the like.

[Effects of the Invention] According to the electrode tool of the present invention having the above configuration,
Since the surface of the workpiece is polished to a mirror finish using a current density that is sufficiently lower than that of normal electrolytic processing and the supply of a small amount of electrolyte, it is possible to mirror-polish the surface of the workpiece that has some unevenness or any free-form surface. can also be applied, and its polishing can be realized with a simple and compact device.

That is, by performing electrolytic abrasive composite polishing using the above-mentioned low current density and a small amount of electrolyte, it is possible to remove only the tips of minute protrusions and perform mirror polishing, and in this case, In particular, since the supply of electrolyte can be made small according to the current density, a small amount is supplied to a reservoir open to the atmosphere inside the tool base, temporarily stored, and the electrolyte is sequentially drained from the reservoir. This is related to the fact that the electrolyte outflow port is provided slightly inward from the periphery of the surface plate of the conductive tool base to allow the electrolyte to flow out. The electrolyte can be uniformly dispersed and leached, and then uniformly flowed out from the center of the viscoelastic polishing body toward the periphery by centrifugal force, so that the viscoelastic polishing body retains the electrolytic solution uniformly over the entire surface. Moreover, not only does it eliminate the need for electrolyte pumping equipment, but there is no reaction force (usually on the order of 100 kg or more) that acts on the tool base due to the pressure of the electrolyte, so the electrode tool can be used like a hand tool. It can be made simple and small.

In addition, a viscoelastic abrasive body is attached to the leading electric tool base of the rotating shaft of the rotary drive machine, and the entire surface or peripheral portion of this viscoelastic abrasive body can be deformed to hold abrasive grains and follow the surface of the workpiece. Even if the surface of the workpiece has some unevenness, the peripheral part of the viscoelastic polishing body deforms to follow the uneven shape and fits to it, so the surface can be polished to a mirror finish with high precision. be able to.

Furthermore, since there is no need to consider electrolyte outflow, the rotation axis of the electrode tool is tilted with respect to a curved surface that evens out the unevenness on the contact surface between the viscoelastic abrasive body and the surface of the workpiece. Processing can be performed by bringing the elastic abrasive body into contact with the workpiece,
Therefore, it becomes possible to mirror-finish any free-form surface.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part showing one embodiment of the present invention,
FIG. 2 is a partially cutaway front view of the electrode tool, and FIG. 3 is a sectional view of a main part showing a mode of polishing using the electrode tool. 12...Rotary drive machine, 14...Rotary shaft, 20...
... Electrode tool, 21 ... Tool base, 22 ... Viscoelastic polishing body, 24 ... Surface plate, 25 ... Back plate, 26 ...
...Liquid reservoir, 30... Electrolyte outflow port, 31... Electrolyte supply opening, 32... Sliding contact surface, 33... Sliding contact for power supply.

Claims (1)

[Claims] 1. An electrode tool for mirror-polishing the surface of a workpiece by supplying a sufficiently lower current density and a small amount of electrolyte than in normal electrolytic machining, which comprises: A conductive tool base attached to the tip is constructed by integrally joining a disc-shaped face plate and a back plate forming a liquid reservoir around the back surface of the face plate at the periphery, and this conductive tool base A contact part for a sliding contact for power supply and an opening for supplying electrolyte are formed on the back plate, and the sliding contact for power supply is brought into contact with the contact part, and an electrolyte supply pipe is connected to the atmosphere within the opening for supplying electrolyte. A large number of electrolyte outflow ports are provided at positions slightly inward from the periphery of the surface plate, and a liquid-permeable viscoelastic abrasive body is attached to this surface plate. An electrode tool for an electrolytic abrasive composite mirror polishing device, characterized in that a peripheral portion of the polishing body is a processing surface that holds abrasive grains and can be deformed to follow the surface of a workpiece.