JPH0420727B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrolytic abrasive composite polishing method for mirror polishing a free-form surface of a member made of a metal material.

[Prior art] Conventionally, an electrolytic abrasive composite is used in which a passive film formed on the surface of a workpiece due to electrolysis is removed using abrasive grains, and the surface is polished by electrolytic action to mirror-polish the surface of the workpiece. Polishing targets flat surfaces, cylindrical surfaces, and other rotating surfaces, and is usually performed with the electrode tool and workpiece held in a nearly constant posture; application to arbitrary free-form surfaces is considered. It has not been. Therefore, this polishing apparatus cannot be applied to polishing free-form surfaces.

However, it is desired in various technical fields to be able to easily mirror-polish arbitrary free-form surfaces, such as molds and other metal parts with complex uneven surfaces, and weld bead parts of stainless steel plates. There is.

Mirror polishing of such free-form surfaces has conventionally been carried out by buffing or manual polishing using an appropriate polishing tool, but this not only requires skill but also creates a very poor working environment. It was hot.

Therefore, in order to apply the above-mentioned electrolytic abrasive composite polishing to free-form surfaces, the present inventors have repeatedly conducted basic experiments and research, but the main reason why it cannot be applied to free-form surfaces is as follows. There was a problem and I needed to solve it.

In other words, in conventional electrolytic polishing equipment, the current density is set in consideration of machining efficiency, etc., so the removal amount associated with polishing is relatively large, and a large amount of electrolytic solution is required in the machining area to eliminate the accompanying electrolytic products. It is necessary to provide a stable supply of Therefore, it is necessary to hold the electrode tool and the surface to be polished parallel to each other over a wide area to allow the electrolyte to flow uniformly between them. Electrolytic processing cannot be applied to arbitrarily curved free-form surfaces.

[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 process that uses a current density that is significantly lower than that of normal electrolytic processing and an extremely small amount of electrolyte. We have discovered that by performing electrolytic abrasive composite polishing, it is possible to remove only the tips of minute protrusions and perform mirror polishing. In this case, since only a small amount of electrolyte is required, there is no need to hold the electrode tool parallel to the surface to be polished, and as a result, it can be applied to polishing free-form surfaces.

The technical problem of the present invention, based on the above-mentioned knowledge, is to use abrasive grains to remove the passive film formed on the surface of the workpiece by electrolysis, and to polish the surface by electrolysis to mirror-polish the surface of the workpiece. An object of the present invention is to make electrolytic abrasive composite polishing applicable to polishing free-form surfaces of metal members.

[Means for Solving the Problems] In order to solve the above problems, the electrolytic abrasive composite polishing method of the present invention includes a viscoelastic polishing body having liquid permeability attached to the surface of a disc-shaped conductive tool base. While the electrode tool is rotated by a rotary drive machine, the viscoelastic abrasive body is brought into contact with the surface of the workpiece consisting of a free curved surface,
At the same time, minute protrusions on the surface of the workpiece are mechanically removed using abrasive grains held in a viscoelastic abrasive body.
While supplying a small amount of electrolyte between the viscoelastic polishing body and the workpiece, current for electrolysis is passed between the two at low current density to average out unevenness on the contact surface between the two. The tool is characterized by mirror-polishing the free-form surface of the workpiece by bringing only the peripheral portion of the viscoelastic polishing body into contact with the workpiece while the rotation axis of the tool is tilted with respect to the plane. It is.

[Operation] When performing electrolytic abrasive composite polishing on the surface of a workpiece, the peripheral part of the viscoelastic polishing body in the electrode tool is lightly pressed against the appropriate position on the surface of the workpiece, and the electrode is applied through the electrolyte supply pipe. An electrolytic current is passed between the electrode tool and the workpiece while an electrolytic solution is supplied to the tool, and the electrode tool is rotated by a rotary drive machine while processing is performed.

In this case, with the rotation axis of the electrode tool tilted with respect to a plane that averages out the unevenness on the contact surface between the viscoelastic abrasive body and the workpiece, only the peripheral portion of the viscoelastic abrasive body is By bringing the machine into contact with the workpiece and machining it, it becomes possible to machine any free-form surface.

The reason why the axis of rotation of the electrode tool can be tilted in this way is based on the above-mentioned findings, and is based on the premise that the current density is extremely low and that electrolytic abrasive composite polishing is performed using an extremely small amount of electrolyte.

In addition, even if there are some irregularities on the surface of the workpiece,
Since the peripheral portion of the viscoelastic polishing body deforms to follow the surface shape and fits onto the surface, mirror polishing is reliably performed.

[Example] The drawings show the configuration of an electrolytic abrasive composite polishing apparatus for carrying out the method of the present invention. This electrolytic abrasive composite polishing device 10 is equipped with a rotary drive device 12 consisting of a motor and a speed reduction device 13 provided on the output side of the device in a pistol-shaped device main body 11, and a rotating shaft rotated by these devices. 14 to the device body 11
The electrode tool 20 is attached to the tip of the electrode.

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-shaped 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 material with liquid permeability such as nylon nonwoven fabric. is attached to the surface of the conductive tool base 21, and when it is formed from a sponge-like member as shown in the figure, a recess 34 is formed inside and it is attached to the tool base 21. , and a contact plate 35 that is in contact with the viscoelastic polishing body 22 and its center.
They can be attached to the rotating shaft by fixing them together with the tool base 21 to the rotating shaft 14 with screws 28. 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 abutment 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. Can be supplied to contact areas.
Therefore, almost no equipment is required for pumping the electrolyte, and the electrode tool 20 has excellent ability to retain the electrolyte, so it can be used not only on horizontal free-form surfaces but also on horizontal free-form surfaces.
Even a nearly vertical curved surface can be polished by stably supplying electrolyte.

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, abrasive grains can also be mixed into the electrolyte solution fed through the electrolyte supply pipe 38.

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 composite polishing device having such a configuration is portable and is used to perform polishing by manually applying light pressure to an appropriate position on the surface of a workpiece.As shown in FIG. When polishing a free-form surface, the electrode tool 2 is supplied through the electrolyte supply pipe 38.
While supplying an aqueous solution such as NaNO ₃ or KNO ₃ to the electrode tool 20 and the workpiece 45, a voltage of several volts to several tens of volts and a current of several amperes (a low current of about several 100 mmA/cm ² The viscoelastic abrasive body 2 in the electrode tool 20 is applied while the electrode tool 20 is rotated by the rotary drive machine 12.
The peripheral portion of the workpiece 45 is processed while being pressed against the free-form surface of the workpiece 45.

In this case, while the rotation axis 14 of the electrode tool 20 is inclined with respect to a plane that averages out the unevenness on the contact surface between the viscoelastic abrasive body 22 and the workpiece 45, the periphery of the viscoelastic abrasive body is Machining is performed with only the part in contact with the workpiece, but generally the inclination angle of the rotation axis with respect to the contact surface is 5.
It is necessary to maintain the angle within a range of approximately 60°, and more preferably within a range of 10° to 45°.

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 electrolytic abrasive composite polishing method of the present invention detailed above, the electrolytic abrasive composite mirror polishing is performed using an extremely low current density and an extremely small amount of electrolyte. , it becomes possible to apply electrolytic abrasive composite polishing to polishing free-form surfaces of metal members,
In particular, by polishing only the peripheral portion of the viscoelastic polishing body in the electrode tool by bringing it into contact with the workpiece, it is possible to polish the minute portion of the viscoelastic polishing body by bringing it into stable contact with the workpiece, By repeating this polishing of minute portions, any free-form surface can be mirror-polished.

Furthermore, since the relative sliding speeds between the viscoelastic abrasive body and the workpiece are approximately equal over the entire contact surface, for example, a small-diameter disc-shaped viscoelastic abrasive body can be applied to the entire surface of the workpiece. as in the case of contact with
There is no difference in speed between the center and the periphery, and the contact surface can be polished uniformly.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an electrolytic abrasive composite polishing device used to carry out the method of the present invention, FIG. 2 is a partially cutaway front view of an electrode tool in the polishing device, and FIG. 3 is a mode of polishing by the polishing device. FIG. 12...Rotary drive machine, 14...Rotary shaft, 20...
... Electrode tool, 21 ... Tool base, 22 ... Viscoelastic polishing body, 38 ... Supply pipe.

Claims (1)

[Claims] 1. An electrode tool, which has a liquid-permeable viscoelastic abrasive body attached to the surface of a disc-shaped conductive tool base, is rotated by a rotary drive machine and applied to the surface of a workpiece consisting of a free-form surface. The viscoelastic abrasive body is brought into contact with the workpiece, and the abrasive grains held by the viscoelastic abrasive body mechanically ablate minute protrusions on the surface of the workpiece. When polishing by passing a current for electrolysis between the two at a low current density while supplying a small amount of electrolyte between the two, the rotation axis of the tool is set against a plane that evens out the unevenness on the contact surface between the two. An electrolytic abrasive compound polishing method characterized by bringing only the peripheral portion of the viscoelastic polishing body into contact with the workpiece in an inclined state, and mirror-polishing the free-form surface of the workpiece.