JPS5933500B2 - Electric discharge machining equipment for roll-shaped workpieces - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention is a roll-shaped workpiece in which the outer circumferential surface of a roll-shaped workpiece is satin-finished with a constant surface roughness (a satin-like uneven surface is formed on the surface of the roll-shaped workpiece). Workpiece (hereinafter simply referred to as roll).

), the moving speed of the electrode in the direction of the roll rotation axis and the rotation speed of the roll can be adjusted by setting the electrical machining conditions of the pulse power supply device that particularly affects the surface roughness of the satin-finished surface. This invention relates to a device that can automatically select and set the optimum value. Conventionally, for example, when finishing the surface of a steel strip rolling roll, especially a cold rolling roll, with a satin finish, hard metal particles such as shot or grid are projected onto the polished roll surface to create impressions on the roll surface. 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 machining gap between an electrode and a workpiece, and periodically applying a pulse voltage between the electrode and the workpiece to generate an electrical discharge. This is a method of processing the surface of a workpiece by

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. This is a method of uniformly applying a satin finish to the surface of a roll using electrical discharge machining. The resulting satin surface not only has a larger difference in unevenness and a much more regular shape than mechanical impressions made by metal particle projection, but also has a shape that is independent of the manufacturing method and hardness of the roll.
In addition, the metal structure on the roll surface is hardened by electrical discharge, making it ideal for use as a rolling roll, and has many other advantages. By the way, the requirements that the electric discharge machining equipment that processes this roll should have are 1. It must be a device that can perform electric discharge machining on rolls in a short time.

2. The device is capable of forming a matte finish with a desired surface roughness that is uniform over the entire surface of the roll.

3. The device must not leave spiral streaks on the roll surface.

Each of these items will be explained next.

First of all, regarding the first term, it is a matter of course that there is no need to explain it, but in electrical discharge machining, even if the discharge energy shown in the waveforms a or b in Figure 1 is supplied to the workpiece, the amount of supplied energy is the same. If so, a machined surface with constant surface roughness can be obtained.

For example, the discharge energy indicated by diagonal lines in Fig. 1a and Fig. 1b
If the discharge energies indicated by diagonal lines in are the same, the machined surface roughness of the workpiece obtained will be the same even if the waveforms are different.
However, the discharge energy per unit time differs between the case where the energy shown in the waveform of FIG. 1a is supplied and the case where the energy shown by the waveform of FIG. In other words, since the energy waveform shown in Figure 1b provides the same surface roughness and improves machining efficiency than that shown in Figure 1a, the energy waveform shown in Figure 1b is generally controlled. This is what has been done. Therefore, in order to process rolls in a short time and achieve the desired surface roughness, the electrical processing conditions of the pulse power supply device that affect the processed surface roughness, such as the pulse peak value, pulse width, and rest width, must be set as desired. Must be set to a value. For example, pulse peak value 30A
The machined surface roughness is 18μRmax in both the case where one pulse width is 8μS and the pause time is 2μS and the case where the pulse peak value is 15A, the pulse width is 16μS, and the pause time is 2μS, but the machining speed in the former is about 0.5gr-/7! IJ! t, the processing speed of the latter is about 0.2gr/Mi! It is t. Normal electrical discharge machining equipment should mainly consider the above matters, but in electrical discharge machining equipment that imparts a satin finish to the roll surface, such as the subject of the present invention, in addition to this, the above-mentioned items 2 or 3 may be taken into consideration. must also be considered.

To explain the second and third terms, they are influenced by the rotational speed of the roll and the moving speed of the electrode in the roll axis direction.

The speed at which the electrode moves in the axial direction of the roll is selected to be such that a pear-shaped surface of the desired shape can be obtained over the entire surface of the roll once the electrode has passed through the roll.

For example, in the case of machining with a surface roughness of 18 μRmax, if the roll diameter is about 600 ψ, the appropriate moving speed is about 2.5 mm/drive. As shown in FIG. 2, although it is desired to apply the satin finish, there are some areas that will be satin-finished and some areas that will not be finished, and if the moving speed is too slow, the processing efficiency will decrease. Also, the rotation speed of the rolls should not be too slow;
For example, even if the electrode width is small and the electrode moves in one rotation of the roll, it is possible to process the entire surface, but although there is almost no difference visually, there are spiral streaks on the roll surface that are undesirable for rolling rolls. remain. The faster the roll rotation speed, the smaller the amount of processing per roll rotation, and the less chance of spiral streaks remaining on the roll, but if the roll rotation speed is too high, the electrical discharge will become unstable and the entire surface will be damaged. A uniform satin finished surface cannot be obtained. As explained above, in order to obtain a desirable roll with a satin finish, the electrical processing conditions of the pulse power supply device that affect the surface roughness of the satin finished surface, the moving speed of the electrode in the roll rotational axis direction, the rotation speed of the roll, etc. It is necessary to select and set each to the optimum value.

This invention was made with attention to the above-mentioned points, and the movement speed of the electrode in the direction of the roll rotation axis is adjusted according to the electrical processing conditions of the pulse power supply device in order to bring the surface roughness of the roll matte surface to a desired value. It is an object of the present invention to provide a roll electric discharge machining device that can selectively set the rotational speed of each roll.

An embodiment of the present invention will be described below with reference to FIG.

That is, in FIG. 3, 1 is a bed, 2 and 2' are bearings installed on the bed 1, 3 is a roll of the workpiece supported horizontally by the bearings 2 and 2', and 4 is a roll of the roll 3. 5 is the bed 1 that is chucking one end.
A roll rotation drive device installed above rotates the burr 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 traverse drive device 7 and a feed screw 8. 9 and 9' are head columns fixed on the base 6, 10 and 10' are electrode holders mounted on the head column 9, and 11 and 11' are connected to the holders 10 and 10' through insulating plates 12 and 17. A plurality of electrodes are attached at equal pitches, and these electrodes 11
, 1V are opposed to the roll 3 through a machining gap, and are made of a copper plate having the shape shown in a perspective view in FIG. 4, and are also formed in the same shape.

13 is a machining tank held on the roll 3; 14 is a machining fluid supplied into the machining tank 13 by a pump not shown; the machining fluid 1 overflowing from the machining tank 13;
4 is filtered and supplied to the processing tank 13 again.

Further, reference numerals 15 and 15' denote pulse power supply devices, which are connected to each of the electrodes 11 and the roll 3 so as to generate an electric discharge. In the figure, the positive electrode is connected to the electrode 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 electrode 11 in a direction perpendicular to the processing surface of the roll 3 is performed independently by each head column 9, 9'. Furthermore, 16 is a general control device which is the central part of the present invention, and by setting the electric machining conditions that affect the roughness of the satin surface of the roll 3 to a desired value, detects the set value of the electric machining condition. According to the set value, the roll rotation drive device 5 is controlled to select and set the rotation speed of the roll 3 to the optimum value, and the column lateral feed drive device 7 is controlled to move the electrodes 11, 1V in the roll rotation axis direction. It is configured to select and set the speed to an optimal value. FIG. 5 is a detailed explanatory diagram of the general control device 16. In this figure, 17 is a pulse peak value setting knob;
8 is the pulse width setting knob, 19 is the pause time setting knob,
20 is a pulse peak value setting circuit, 21 is a pulse width setting circuit, 22 is a pause time setting circuit, 23 is a discrimination circuit, 24 is a memory circuit, 25 is a roll rotation motor rotation speed control circuit, 26 is a column traversing motor rotation speed control circuit,
27 is a motor for rotating the roll, and 28 is a motor for transversely feeding the column. When the electrical machining conditions such as pulse peak value, pulse width, and pause time are set to desired values, the discrimination circuit 23 selects the roll rotation speed and column lateral feed speed for the set electrical machining conditions from the data stored in the memory circuit 24. , commands the control circuits 25 and 26. The above memory circuit 2
4 stores in advance data as shown in the following table obtained from various experimental results.

Note that the values shown in this table apply to the configuration shown in Figure 3.
Roll diameter 600φ, electrode thickness 0.811, electrode width 50U
1. This is for the case where the electrode material is copper. Now, when performing processing with a surface roughness of 14 μRnlax using the roll and electrode shown in the above conditions, the pulse peak value is set to 30 CA], the pulse width is 8 [μS], and the rest time is 16 [μS]. By inputting to the circuit 20, the pulse width setting circuit 21, and the pause time setting circuit 22, based on the contents stored in the memory circuit 24, the determination circuit 23 determines the optimum roll circumferential speed of 9 m/Mm and the optimum lateral feed. Speed 1.5mm/
The dragons are output to the roll rotation motor rotation speed control circuit 25 and the column lateral feed motor rotation speed control circuit 26, respectively.
Optimal machining is achieved by driving the roll rotation motor 27 and column traversal motor 28. As mentioned above, this inventive device sets the electrical processing conditions of the pulse power supply device in order to obtain the desired satin finished surface roughness, thereby meeting other requirements for obtaining a desired roll with a satin finished surface in a short time. The rotational speed of the roll and the speed of movement of the electrode in the direction of the rotational axis of the roll can be selected and set to the optimum value, so that it is possible to obtain a satin finish on the surface of the roll very easily and in a short time. It is possible to provide a roll electrical discharge machining device in which machining conditions can be set.

[Brief explanation of the drawing]

Figure 1 is a diagram for explaining the relationship between discharge energy, machined surface roughness, and machining efficiency, and Figure 2 is a diagram for explaining the relationship between the moving speed of the electrode in the roll rotation axis direction and the satin finished surface obtained on the roll. Fig. 3 is an overall schematic configuration diagram showing an embodiment of the present invention, Fig. 4 is a perspective view showing an example of the electrode shape used in the device shown in Fig. 3, and Fig. 5 shows the central part of the invention. FIG. 2 is a diagram for explaining a general control device.

Claims (1)

[Claims] 1 While rotating the roll-shaped workpiece, move the electrode in the direction of the rotation axis of the roll-shaped workpiece, connect a pulse power supply device between the electrode and the roll-shaped workpiece, and rotate the roll-shaped workpiece. In a device that processes the surface of the satin-finished surface, the electric processing conditions of the pulse power supply device that affect the surface roughness of the satin-finished surface are set to a desired value, and the set values of the electrical processing conditions are detected and adjusted. An electrical discharge machining apparatus for a roll-shaped workpiece, comprising a general control device that selects and sets the moving speed of the electrode in the direction of the rotation axis and the rotation speed of the roll-shaped workpiece to optimal values, respectively, according to set values.