JPH05177446A - Electric discharge machining device - Google Patents

Abstract

PURPOSE:To improve the finished form of a round bar electrode and shorten its working time by providing a numerical control unit for giving an optimum spindle rotating speed to a spindle rotating device on occasion, and a memory device for storing the optimum spindle rotating speed and electric condition every electrode diameter. CONSTITUTION:Prior to feeding a round bar electrode while rotating for electric discharge machining, a start electrode diameter and a target finished electrode diameter are first given into a numerical control unit 5, whereby the spindle rotating speed and working current optimum to the working judged from a memory device 11 by the numerical control unit 5, and the numerical control unit 5 sets the set values in a program as working conditions. Further, during the working, the numerical control unit 5 judges the electrode diameter at the point of time on occasion, selects the optimum rotating speed of a main spindle 8 in this electrode diameter, changes the rotating speed of the main spindle 8 on occasion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric discharge machine.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional electric discharge machine. In the figure, 1 is a round bar electrode for machining, 2 is a master electrode for finishing this round bar electrode to a specified diameter, 3 is an object to be machined with an electrode finished to a specified diameter, and 4 is a pulse current in a machining gap. Pulse current supply device for energizing
6 is a processing tank, 7 is processing oil contained in this processing tank, 8 is a main shaft, and 9 is a rotating device provided on this main shaft. The conventional electric discharge machine is configured as described above, and the round bar electrode 1 attached to the main shaft 8 equipped with the rotating device 9 in oil 7 and the master electrode 2 for machining to a specified diameter are opposed to each other, and pulsed. The pulse current supplied from the current supply device 4 is applied to the machining gap, and the round bar electrode 1 is fed while rotating according to a command from the numerical control device 5 to machine to a specified diameter. Next, the round bar electrode 1 is moved to the work piece 3 to be processed.

[0003]

At this time, the spindle rotational speed commanded to the rotating device 9 and the machining conditions given to the program are processed by rough machining data as shown in FIG. 3 and FIG. The numerical control device is instructed based on the intuition and experience of the operator himself, and the change of the spindle speed during machining is a very rough setting, so the command value differs depending on the experience of the operator. There is a problem that this command value difference appears as a considerable difference in processing time, finishing accuracy, and the like.

The present invention has been made in order to solve the above problems, and by giving an electrode diameter before the start of machining and a target finish diameter, and further during machining, the electrode diameter at that point in time. It is an object of the present invention to obtain an electric discharge machining device capable of performing electric discharge machining using the optimum spindle rotation speed at the electrode diameter and the optimum machining condition according to the rotation speed by the numerical control device.

[0005]

DISCLOSURE OF THE INVENTION An electric discharge machine according to the present invention is a numerical control device for giving an optimum spindle speed to the spindle speed, and a storage device for storing the optimum spindle speed and electrical conditions for each electrode diameter. It is equipped with.

[0006]

The electric discharge machining apparatus according to the present invention gives the starting electrode diameter before machining and the target finishing electrode diameter so that the optimum spindle rotation speed for each electrode diameter and the optimum spindle rotation speed can be obtained from the storage device that accumulates machining conditions. And electrical conditions are automatically selected.

[0007]

【Example】

Example 1. An embodiment of the present invention will be described below. In FIG. 1, a round bar electrode 1 attached to a spindle 8 equipped with a rotating device 9 whose rotation speed can be arbitrarily set in a processing oil 7 and a master electrode 2 installed on a table 10 are opposed to each other to Feeding electrical discharge machining is performed while rotating.
Before the machining, the numerical control device 5 first determines the optimum spindle speed and the average machining current for the machining from the storage device 11 by giving the starting electrode diameter and the target finishing electrode diameter in the numerical control device 5, The control device 5 sets the set value in the program as the processing condition. Further, during machining, the numerical control device 5 discriminates the electrode diameter at that time at any time, selects the optimum spindle rotational speed at that electrode diameter, and changes the spindle rotational speed at any time.

Next, the database of the storage device 11 for storing the optimum rotational speed of the spindle rotating device 9 and the machining conditions will be described. FIG. 3 is a diagram showing a relationship between an electrode diameter to be finished by electric discharge machining, an optimum spindle rotation speed, and a machining current value. For example, when finishing the starting electrode diameter φ10 mm to φ5 mm, the spindle rotation speed at φ10 mm is 20 rpm, and the machining conditions at that time are controlled so that the average machining current is 25A. Then, the rotation speed at φ5 mm is 85 rpm, and the processing condition at that time is controlled to be 10 A. At this time, as the diameter gradually decreases from φ10 mm to φ5 mm, the machining current changes from 25 A to 10 A and the rotation speed changes from 20 rpm to 85 rpm, and the optimum value as shown in FIG. 3 is automatically set. The above data is a well-known fact, and the storage device 11 stores data on the spindle rotation speed and machining conditions for each electrode diameter as shown in FIG.

As described above, according to the present invention, by giving the electrode diameter before the start of machining and the target finishing diameter,
The optimum spindle rotation speed and machining current are selected, and the spindle rotation speed control and machining current control are performed by discriminating the electrode diameter during machining, which shortens the machining time and increases the machining accuracy.

[0010]

In the electric discharge machine according to the present invention, the numerical control device gives the optimum spindle rotation speed to the spindle rotation device, and further the optimum electrical condition is given by the numerical control device. The finished shape was further improved, and the processing time was shortened. The shape accuracy when processing the workpiece with the round bar electrode was improved and the processing time was shortened.

[Brief description of drawings]

FIG. 1 is a diagram showing an electric discharge machining method according to an embodiment of the present invention.

FIG. 2 is a diagram showing a conventional electric discharge machining method.

FIG. 3 is a diagram showing a relationship between a spindle rotation speed and a target finishing electrode diameter.

FIG. 4 is a diagram showing a relationship between an electrode diameter and electrical conditions.

FIG. 5 is a diagram showing an example of processing condition setting used conventionally.

[Explanation of Codes] 1 round bar electrode for processing 2 master electrode 3 workpiece 4 pulse current supply device 5 numerical control device 6 processing tank 7 processing oil 8 spindle 9 rotating device 10 table 11 data storage unit

Claims (1)

[Claims] 1. A spindle having a rotating device, a round rod electrode fixed to this spindle and a master electrode set on a table face each other in a working fluid, and a pulse current is passed to feed the round rod electrode. In an electric discharge machine for performing an electric discharge machining method for finishing to a designated diameter, a numerical control device for giving an optimum spindle rotation speed to a spindle rotation device at any time, and a storage device for storing the optimum spindle rotation speed and electric condition for each electrode diameter are provided. The electrical discharge machining device characterized in that