JPS6153180B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for positioning a liquid level in a machining tank of a roll electric discharge machine that performs electric discharge machining on the outer peripheral surface of a roll-shaped workpiece.

Conventionally, when finishing the surface of steel strip rolling rolls, especially cold rolling rolls, with a satin finish, a method has been adopted in which hard metal particles such as shot or grit are projected onto the polished roll surface to create impressions on the roll surface. However, in recent years, this type of machining has come to be performed using electric discharge machining.

As is well known, electric discharge machining is a method of machining the surface of a workpiece by periodically applying a pulse waveform voltage between an electrode and the workpiece to generate an electric discharge.
By repeating such electric discharge machining on the roll surface, rotating the roll in the circumferential direction, and at the same time gradually moving the electrode in the direction of the rotation axis of the roll, the roll surface will undergo a continuous spiral satin finish. The roll surface can be covered with discharge marks. This is a method of uniformly applying a satin finish to the roll surface using electrical discharge machining. The resulting satin surface not only has a larger difference in unevenness and a much more regular shape than the mechanical indentations made by metal particle projection as described above, but the shape is also influenced by the manufacturing method and hardness of the roll. It also has many advantages, such as the metal structure on the roll surface being hardened by electrical discharge, making it ideal for use as a rolling roll.

However, in the past, roll electric discharge machines for performing satin finish on the roll surface were able to machine only a few types of roll-shaped workpieces and the roll outer diameter range was small (for example, the roll outer diameter range was φ520).
~φ600). Therefore, the liquid level in the machining tank for immersing the rolls in the machining liquid remained constant regardless of the rolls, and there was no particular problem.

However, recently, the superiority of electric discharge machining for roll-shaped workpieces has been recognized, and one roll electric discharge machine can process various rolls, such as a roll with an outer diameter range of φ290.
There was a demand for processing rolls of ~φ610. In that case, in the conventional machining tank liquid level constant method, when machining a roll with a small outer diameter, most of the electrode holder is immersed in the machining fluid (the length of the electrode at the tip of the electrode holder is Due to the processing characteristics, it is necessary to make the length as short as possible), which causes problems such as sludge such as processing powder adhering to the hydraulic cylinder attached to the electrode holder and the sliding surface, which prevents it from functioning as an electrode holder. was.

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a method for automatically positioning the liquid level in a processing tank according to the outer diameter of the roll.

An embodiment of the present invention will be described below with reference to the drawings. Figure 1 is a schematic diagram of the roll electrical discharge machine.
1 is a roll that is a workpiece, 2 is a bearing for horizontally supporting the roll 1, 3 is a processing tank for storing machining fluid, 4 is a chuck for chucking one end of the roll 1, and 5 is a rotating part for rotating the roll 1. 6 is an electrode, 7 is an electrode holder for feeding and holding the electrode 6, and 8 is a head for servo feeding the electrode 6 for processing. The head 8 is moved parallel to the roll rotation axis by rotating the rotation shaft 10 by a head traversing drive device 9. Reference numeral 11 denotes a power source that supplies discharge energy between the roll 1 and the electrode 6. In the roll machining method of such a roll electric discharge machine, the roll 1 is rotated at a constant speed by the roll drive device 5, and the electrode holder 7 is connected to the roll rotation axis while causing electric discharge between the roll 1 and the electrode 6. The entire outer periphery of the roll 1 is subjected to a satin finish by moving in parallel.

Conventionally, in such a roll electric discharge machine, the overflow position of the machining tank was fixed to keep the liquid level constant, as shown in FIG. 2, because the change in the outside diameter of the roll was small. In the figure, 12 is a machining fluid.
However, when the liquid level in the machining tank is kept constant in this way, when the outer diameter of the roll changes and becomes smaller, the tip of the electrode holder 7 is immersed in the machining fluid 12, as shown in FIG. This causes the problem that sludge such as processing powder adheres to the hydraulic cylinder and sliding surfaces (not shown in the figure) attached to the electrode holder part 7, making it impossible to function as an electrode holder. It was hot.

Therefore, the present invention provides a method for automatically positioning the liquid level height of the processing tank according to the outer diameter of the roll to be processed, and will be specifically explained below with reference to the drawings.

In this invention method, first, as shown in FIG. 4, the electrode holder 7 is positioned in advance at the processing position according to the size of the roll 1, and the partition plate 13 for overflowing the surface of the processing fluid is placed at the lower limit in the figure. keep it in position. Next, the machining liquid is poured into the machining tank 3, and when the liquid level rises to the liquid level overflow partition plate 13, the partition plate vertical drive device 14
is driven, and the liquid level overflow partition plate 13 is raised upward (toward the drive device 14 side) at a speed slower than the liquid level rising speed. Thereafter, when the liquid level rises and the liquid level positioning float switch 15 attached to the electrode holder 7 is activated by the machining liquid, the input to the partition plate vertical drive device 14 is cut off, and the liquid level overflow partition plate 14 is turned off. make it stop. In the manner described above, the processing tank liquid level height can be automatically set according to the outer diameter of the roll 1. FIG. 5 shows a state in which the liquid level height is determined when the roll outer diameter is large, and FIG. 6 shows a state in which the liquid level height is determined when the roll outer diameter is small. As can be seen from the figure, even if the roll outer diameter changes, the state in which the tip of the electrode holder 7 is immersed in the machining liquid 12 does not change, and the function is not impaired.

As described above, according to the method of the present invention, it is possible to automatically determine the liquid level in the machining tank according to changes in the roll outer diameter, prevent the electrode holder from being immersed in the machining liquid, and The function of the holder is not impaired, and its practical effects are extremely large.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the general configuration of a roll electric discharge machine, Fig. 2 is an explanatory diagram showing the state of a conventional machining tank,
Fig. 3 is an explanatory diagram showing the case of machining a roll with a small outer diameter in a conventional machining tank state, Fig. 4 is an explanatory diagram showing the liquid level height positioning method of the present invention, and Fig. 5 is an explanatory diagram showing the roll outer diameter. Fig. 6 shows the state in which the liquid level height is determined by the method of the present invention when the
The figure shows a state in which the liquid level height is determined by the method of the present invention when the roll outer diameter is small.
Note that the same reference numerals in the figures indicate the same parts. 1... Roll-shaped workpiece, 3... Processing tank, 6...
... Electrode, 7 ... Electrode holder, 8 ... Head, 1
2... Processing liquid, 13... Partition plate for liquid level overflow, 14... Partition plate vertical drive device, 15... Float switch for liquid level positioning.

Claims (1)

[Claims] 1 After positioning the electrode holder with a float switch for liquid level positioning at the processing position of the roll-shaped workpiece installed in the processing tank, the processing liquid is injected into the processing tank, and the liquid level is movable up and down. When the level of the machining fluid rises to the lower limit position of the overflow partition plate, the partition plate is raised at a speed slower than the rising speed of the machining fluid level, and the partition plate is raised at the position where the float switch for positioning the liquid level is activated. A method for positioning a liquid level in a machining tank of a roll electric discharge machine, which is characterized by stopping a plate.