JPS5949855B2 - Electric discharge machining equipment for roll-shaped workpieces - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric discharge machining apparatus that processes the surface of a roll-shaped workpiece (hereinafter simply referred to as a roll), for example, processes to uniformly apply a matte surface of arbitrary roughness. It is.

The processing method currently commonly used to create this satin finish is to project hard metal particles such as shot grids onto the polished roll surface to create impressions on the roll surface, but recently electrical discharge machining has been used. We are trying a method using .

In electrical discharge machining, a narrow gap between the electrode and the surface of the workpiece is
For example, an insulating liquid such as kerosene is supplied, and a rectangular wave voltage is periodically applied between the electrode and the workpiece to cause a discharge.
This is a method of processing a workpiece.

When machining is performed using this method, the surface of the workpiece after machining becomes a satin surface covered with discharge marks.

While repeating such electrical discharge machining on the roll surface, the roll is rotated in the circumferential direction (arrow R in the figure), and at the same time, the electrode is gradually moved parallel to the rotation axis of the roll, so that the roll surface becomes continuous. It was then subjected to spiral electrical discharge machining, and finally the entire surface was finished with a matte finish. This is a method of uniformly applying a satin finish to the surface of a roll using electric discharge machining.

The resulting satin surface not only has a larger difference in unevenness and a much more regular shape compared to mechanical impressions made by metal particle projection, but also has the advantage that the satin surface shape is not affected by the manufacturing method or hardness of the roll. It has many advantages.

By the way, in the current electrical discharge machining of rolls, there is a limit to how much machining time can be shortened by using a single electrode, so in order to improve machining efficiency, we have created an optimal width parallel to the rotational axis of the roll. A method of arranging multiple electrodes at regular intervals has been taken, but since there is a limit to the electrode mounting relative to the roll width, it is also necessary to place the electrodes at regular intervals in the circumferential direction of the roll rotation. A structure is adopted in which these are arranged in a stacked manner.

In addition, the electrode used for this electric discharge machining was experimentally
．． It has been confirmed that a copper plate with a thickness of about 5 to 21 m is optimal.

However, it has been experimentally confirmed that when the plurality of electrodes are opposed to the roll processed surface, the facing angle has a large effect on the processed surface.

FIG. 1 is a schematic configuration diagram showing a state in which electrodes are attached in a conventional roll electric discharge machine, and for explaining a case where the electrodes are attached without considering the facing angle α with respect to the roll machined surface. In this figure, 1 is a roll which is a workpiece, 2 is a plurality of laminated electrodes, and in the figure, four electrodes are stacked, 3 is an electrode holder that holds the plurality of electrodes 2 fixedly, and 4 is an electrode holder. A head device supports and servo feeds the electrode holder 3, 5 is an insulating liquid filled between the roll 1 and the electrode 2, and 6 is a processing tank that stores the insulating liquid.

The roll 1 is rotated in the direction of the arrow by a roll rotation drive device (not shown), and the head device 4 moves a predetermined distance in the direction of the rotation axis (longitudinal direction) of the roll 1 to smooth the surface of the roll 1 into a matte finish. It is finished in a shape. By the way, in actual processing, the gap 9 between the roll 1 and the electrode 2 shown in the figure may become zero due to factors such as eccentricity during roll rotation and roll surface accuracy. If the electrode 2 is arranged so that the extension line 11 of the facing angle α intersects on the left side of the roll center o on the X axis, the electrode 2
will have no way to escape and will be caught in the direction of rotation of roll 1.

If such a situation occurs, not only will the shape of the electrode 2 be deformed, but also a short circuit phenomenon that must be avoided in electrical discharge machining will occur, which will seriously affect the finished machined surface.

If the response of the servo feed of the head device 4 is very fast, the electrode 2 can be separated from the surface of the roll 1 instantly, and there should be no problem in practical use. There is a limit to the speed, and therefore it is necessary to minimize the occurrence of the above situation within the practical servo response speed. The present invention has been made with attention to such points, and one embodiment will be described below with reference to the drawings.

As shown in FIG. 2, by configuring the extension lines 11 of all the electrodes 2 at the angle α facing the roll 1 to intersect on the right side of the roll center o of the X-axis shown in the figure, that is, with the roll center By tilting the electrode in the direction opposite to the rotational direction R (arrow A) with respect to the line 12 connecting it to the processed part and facing the roll, the above-mentioned entrainment phenomenon of the electrode 2 can be suppressed to a minimum. In addition, by appropriately selecting this opposing angle α, it is possible to minimize the short circuit phenomenon within a practical servo response speed, and to process the roll surface without causing any practical problems in actual machining work. I was able to confirm it.

As described above, this invention prevents mechanical deformation of the electrode by optimally selecting the angle at which the electrode faces the roll-shaped workpiece.
Furthermore, uniform electrical discharge machining can be achieved without causing short circuit phenomena.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram illustrating a conventional machining state, and FIG. 2 is a schematic configuration diagram for proving the present invention.

Claims (1)

[Claims] 1. In an electric discharge machining device that processes the circumferential surface of a roll-shaped workpiece while an electrode is placed opposite to the circumferential surface of the roll-shaped workpiece and the workpiece and the electrode are moved relative to each other in the circumferential direction, the electrode is , line l_2 connecting the center of the workpiece and the processing part
On the other hand, an electrical discharge machining apparatus for a roll-shaped workpiece, characterized in that the roll-shaped workpiece is disposed facing the workpiece at a predetermined angle in a direction opposite to the rotational direction of the roll-shaped workpiece.