JPS6361130B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to electrical machining of a roll that finishes the outer circumferential surface of a roll-shaped workpiece (hereinafter referred to as a roll) with a constant surface roughness using electrical discharge machining. It is about the method.

[Prior art]

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 shots and grit are projected onto the polished roll surface to form impressions on the roll surface. It was getting worse.

However, in recent years, attempts have been made to perform this type of machining by electrical discharge machining.

As is well known, electrical discharge machining involves interposing an insulating liquid, such as kerosene, in a narrow discharge gap between an electrode and a workpiece, and periodically applying a pulse voltage between the electrode and the workpiece. This is a method of machining a workpiece by causing electrical discharge.

By repeating such electrical 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. For this purpose, there is a method of uniformly applying a satin finish to the surface of the roll using electric discharge machining.

The pear surface obtained in this way not only has a larger difference in unevenness and a much more regular shape than mechanical impressions made by metal particle projection, but the shape is also influenced by the manufacturing method and hardness of the roll. Zumata,
It 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 recent roll processing methods,
In order to shorten processing time, processing using multi-segmented electrodes has come to be performed. In this way, when the number of divisions of a multi-segmented electrode becomes very large, in order to prevent the division processing efficiency from decreasing and to make the mechanical structure stable, it is necessary to A head column (hereinafter referred to as the head and column as one unit) is provided, and a split electrode is attached to each head column, and during machining, the multiple head columns are moved in the direction of the rotation axis of the roll during electrical discharge machining. Methods of doing this have begun to be attempted.

Fig. 1 is for explaining a conventional roll electric discharge machining method using a multi-segmented electrode. A workpiece roll supported horizontally by bearings 2 and 2'; 4 is the roll 3;
A roller 5 chucking one end of the roller 5 is a roll rotation drive device installed on the bed 1, which rotates the roller 4 and rotates the roll 3. Reference numeral 6 denotes a base, which is configured to be slidable on the bed 1 from side to side in the figure by the action of a column lateral feed drive device 7 and a feed screw 8. 9, 9' are head columns fixed on the base 6; 10, 10' are electrode holders mounted on the head columns 9, 9'; 11, 1;
1' is connected to the holder 1 through the insulating plates 12, 12'.
A plurality of electrodes 11 and 11' are mounted at equal pitches at 0 and 10', and these electrodes 11 and 11' are made of a copper plate having a shape shown in a perspective view in FIG. It is formed of
Moreover, they are formed in the same shape. 13 is the processing tank held on the roll 3, 14 is the processing tank 1
The machining fluid 14 that overflows from the machining tank 13 is passed through and is supplied to the machining tank 13 again. Further, reference numerals 15 and 15' denote pulse power supply devices, which are connected to form a discharge between each of the electrodes 11 and 11' and the roll 3. In the figure, the positive electrode is connected to the electrodes 11 and 11', and the negative electrode is connected to the roll 3, but processing can also be performed in the reverse direction. Further, the spindle feeding of the electrodes 11, 11' in a direction perpendicular to the machined surface of the roll 3 is carried out by each head column 9,
It is performed independently at 9'.

In such a configuration, conventionally, the roll 3 and the electrode 11 are connected to each other while rotating the roll 3 by the celery 4.
11' to generate electric discharge and perform electric discharge machining,
Furthermore, the base 6 is slid left and right by the action of the feed screw 8, and the head columns 9, 9' are moved left and right.

In the case of this conventional method, the stroke of the machining feed of the head columns 9, 9' in the direction of the roll rotation axis (hereinafter abbreviated as head column machining feed) is
If the mounting pitch (hereinafter abbreviated as electrode mounting pitch) in the direction of the roll rotation axis of 1 and 11' is larger or smaller than P, a uniform matte surface will not be obtained. The total machining length (hereinafter abbreviated as total machining length) L _i in the direction of the roll rotation axis is expressed by the following equation as shown in FIG.

L _i =P×i+d...(1) However, L _i : Total machining length P : Electrode mounting pitch i : Number of electrodes in the direction of the roll rotation axis (hereinafter abbreviated as the number of electrodes) d : Roll rotation axis of the electrode Width in Direction (hereinafter abbreviated as electrode width) Therefore, by selecting the number i of electrodes used for machining, electric discharge machining can be performed on rolls having various machining lengths Li. However, if the length L corresponding to the effective length of the roll and the total machining length Li do not match, when machining is performed using i electrodes, the fourth
As shown in the figure, the following equation (2) holds true.

L _i-1 <L < L _i ...(2) However, L _i-1 : Total machining length when the number of electrodes is (i-1) L _i : Total machining length when the number of electrodes is i L: effective length of the roll In such a situation, the processing position of one of the electrodes 11, 11' will deviate from the effective length of the roll during the process of processing and feeding the head columns 9, 9'. In the case shown in Fig. 4, when machining is started by aligning the left end surface of the left end electrode with the left end of the desired surface of the roll and the head column is fed rightward, the right end electrode This indicates that the machining position deviates from the effective length of the roll. Also, align the right end electrode with the right end of the roll effective length,
When processing is fed to the left, the processing position of the left end electrode will deviate from the effective length of the roll.
That is, if a part of the machining position of the electrode deviates from the effective length of the roll and machining is continued, the total machining length will not match the effective length of the roll. Furthermore, when processing is performed in this state, the electrode wears out on one side due to uneven electrode consumption, as shown in FIG. If the next machining is performed using such an electrode that has become uneven, the electric discharge will be concentrated at the tip of the electrode that has become uneven, making it impossible to machine the desired surface of the roll into a uniform satin surface. Become.

When attempting to process the entire effective length of the roll based on the above-mentioned preconditions, one possible method is to provide a dedicated head for processing the end of the roll. This head, like the other heads, starts processing left and right at the same time as processing starts.
When the machining position of the electrode reaches the effective length of the roll, that is, when it reaches the end of the roll, if electric discharge machining is continued with the machining feed stopped, a uniform satin surface can be obtained over the entire surface including the end.

However, even if the rolls are of the same type, the effective length of a new roll differs greatly from an old roll that is on the verge of being discarded. This is because the end of a normal roll is not a right angle, but has an angle. An example is shown in FIG.
As is clear from the figure, as the roll becomes worn out and the diameter for wear and re-polishing becomes smaller, the effective length of the roll increases. That is, the positions of the end portions of the rolls are usually different even if the rolls are of the same type.

Therefore, if processing is to be carried out over the entire effective length of a roll, it becomes necessary to preset the effective length of each roll in some way, depending on the diameter, even if the rolls are of the same type. .

[Summary of the invention]

The present invention was devised in view of this situation, and provides a roll in which the effective length of the roll can be automatically set by presetting the type of roll, and the end of the roll can be detected. The present invention provides a method for electrical discharge machining of a shaped workpiece.

In the electric discharge machining method according to the present invention, a plurality of head columns equipped with electrodes facing the roll-shaped workpiece are provided, and the plurality of head columns are moved in the direction of the rotation axis of the roll-shaped workpiece to produce the roll-shaped workpiece. In the electrical discharge machining method for a roll-shaped workpiece that finishes the outer peripheral surface of the workpiece, the diameter and effective length of the roll when new and the diameter and effective length of the roll when discarded are measured in advance. I'll keep it. Then, during electrical discharge machining, the roll diameter is calculated based on the distance from the upper limit position of the electrode feeding mechanism to the machining start position, and by taking advantage of the fact that the end of the roll is not at a right angle but at a certain angle, The effective length of the roll surface is calculated based on the roll diameter and the above dimensions, and the roll end is automatically set based on this effective length of the roll.

[Embodiments of the invention]

FIG. 7 is a schematic configuration diagram for explaining a method according to an embodiment of the present invention. Of course, in actual electrical discharge machining, this apparatus and the apparatus shown in FIG. 1 are combined.

First, a method for calculating the effective length of the roll will be explained. Let D _A be the roll diameter when new, L _A be the effective length of the roll, D _B be the roll diameter when discarded, and L _B be the effective length of the roll. When the roll diameter is D, the effective length L of the roll is It is expressed by the following formula.

L=L _A +L _B -L _A /D _A -D _B (D _A -D) Therefore, if the roll diameter is detected, the effective length of the roll can be calculated using the above formula, and the effective length of the roll is clear. When this happens, the position of the end of the roll becomes obvious.

Next, the control system shown in FIG. 7 will be explained. In the figure, 20 is a head dedicated to end processing, 21 is a roll diameter detection device, 22 is an arithmetic circuit that calculates the effective length of the roll based on the roll diameter, and 23 is a processing feed control circuit for the end processing head 20. It is.

The end processing head 20 is lowered from a predetermined position and stopped at the discharge start position. Based on the moving distance at this time, the roll diameter detection device 21 detects the diameter D of the roll. This roll diameter D is supplied to the calculation circuit 22. The arithmetic circuit 22 stores data of D _A , L _A , D _B , and L _B of each roll in advance, and uses these data and the roll diameter D to determine the effective length L of the roll. Effective length L of this roll
is given to the machining feed control circuit 23 as a reference value.

Here, when electrical discharge machining is started and the end machining head 20 reaches the end, the machining feed control circuit 23 operates to stop the machining feed. Then, by continuing electric discharge machining by the head 20 while machining feed is stopped, a uniform satin surface can be obtained over the entire surface including the edges.

〔Effect of the invention〕

Since the method according to the present invention detects the end of the roll as described above, it is possible to process the roll over its entire effective length. For example, if the entire length of the roll is not processed but only the length required for rolling is processed, a polishing process is required when re-staining the worn roll by rolling, but this is effective based on the method according to the present invention. If the entire length is worked, that step can be omitted, which is very advantageous for the rolling process.

[Brief explanation of drawings]

Figure 1 is a schematic diagram for explaining the conventional method, Figure 2 is a perspective view of the electrode, Figure 3 is an explanatory diagram showing the total machining length, and Figure 4 shows that the machining position of the right end electrode is the effective length of the roll. FIG. 5 is an explanatory diagram showing uneven wear of the electrode. FIG. 6 is an explanatory diagram for explaining the roll shape. FIG. 7 is an explanatory diagram for explaining the method according to an embodiment of the present invention. FIG. In the figure, 3 is a roll, 7 is a column traversal drive device, 9 and 9' are head columns, 11 and 11' are electrodes, 15 and 15' are pulse power supplies, 20 is a head dedicated to end processing, and 21 is a roll diameter detection device, 2
2 is an arithmetic circuit, and 23 is a processing feed control circuit.
In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1 A plurality of head columns equipped with electrodes facing the roll-shaped workpiece are provided, and the plurality of head columns are moved in the direction of the rotational axis of the roll-shaped workpiece to create a satin finish on the outer peripheral surface of the roll-shaped workpiece. In the electric discharge machining method for a roll-shaped workpiece to be finished, the roll diameter and effective roll length of the roll-shaped workpiece when new and the roll diameter and roll effective length when scrapped are measured in advance, Then, calculate the roll diameter based on the distance from the upper limit position of the electrode feeding mechanism to the processing start position, calculate the effective length of the roll surface based on this calculated value and the above dimensions, and automatically set the roll end. A method for electric discharge machining of a roll-shaped workpiece, characterized by: