JP2717474B2 - EDM method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric discharge machining method,
It relates to the determination of the end of processing.

[0002]

2. Description of the Related Art Machining end determination methods in electric discharge machining are roughly classified into the following. (1) A method of determining the end of processing by reaching the processing depth. (2) A method of determining that the machining has been completed when a specified time has elapsed. Of these, in the finishing processing area, a method of determining that the processing is completed when the designated time (2) has elapsed is often used.
The reason is that, as disclosed in Japanese Patent Publication No. 60-3933, the discharge gap in the finish machining area is very unstable. This is because processing time is required, and conversely, the surface may not be finished.

FIG. 3 is a configuration diagram for explaining a conventional machining end determination method. In the figure, reference numeral 1 denotes an axis movement amount detection mechanism,
A comparison mechanism 2 compares the commanded machining depth with the movement amount of the axis movement amount detection mechanism 1 and outputs a coincidence signal. 3 counts a designated designated time and outputs a coincidence signal when the time has elapsed. The output timer mechanism 4 is a determination mechanism that switches the coincidence signal from the comparison mechanism 2 and the timer mechanism 3 or performs a logical addition to output a processing end signal.

Next, the operation will be described. First, when the machining depth is instructed, the movement amount during machining is detected by the movement amount detection mechanism 1 and transmitted to the comparison mechanism 2, and the comparison mechanism 2 transmits the movement amount to the determination mechanism 4. The determination mechanism 4 outputs a processing end signal by the logical sum with the match signal from the comparison mechanism 2 even if there is no match signal from the timer mechanism 3.

When the designated time is instructed, the timer mechanism 3 counts the time, and when the designated time matches the count value, transmits a match signal to the determination mechanism 4.
In the determination mechanism 4, even if there is no coincidence signal from the comparison mechanism 2, the logical sum with the coincidence signal from the timer mechanism 3 is used.
Outputs the processing end signal.

Further, when both the machining depth and the designated time are commanded, if either the coincidence signal from the comparison mechanism 2 or the coincidence signal from the timer mechanism 3 is present, the determination mechanism 4 outputs the machining end signal. Is output.

The machining depth instructed here can be uniquely obtained from the machining drawing, but the designated time is roughly estimated from past data according to the machining conditions and machining area. The time is commanded.

[0008]

However, in the conventional method, it is difficult to specify the time in the processing method in which it is determined that the processing is completed when the specified time elapses. If it is too small, the surface will not be finished.

The present invention has been made to solve such a problem, and automatically sets an appropriate processing time,
An object of the present invention is to provide an electric discharge machining method that counts the time and determines the end of machining.

[0010]

According to a first aspect of the present invention, there is provided an electric discharge machining method for judging the end of machining based on the elapse of a set time, wherein only the actual machining time during electric discharge with a workpiece is counted. Is used to determine the elapse of the set time.

According to a second aspect of the present invention, there is provided an electric discharge machining method for judging the end of machining based on a lapse of a set time, wherein a machining area is obtained from an axial movement amount per unit time and machining conditions. The time obtained by multiplying the ratio by the actual machining time per unit area specified in advance is set as the set time.

According to a third aspect of the present invention, there is provided an electric discharge machining method for judging the end of machining based on the elapse of a set time, wherein a machining area is obtained from an axial movement amount per unit time and machining conditions. The set time is calculated from the actual machining time per unit area for obtaining the surface.

[0013]

In the present invention, the total current required for the entire machining area is calculated from the current required for the desired machining per unit area of the workpiece, and the total current is supplied to the workpiece. The end time of the machining is determined by counting the length of time.

[0014]

FIG. 1 is a block diagram for explaining an electric discharge machining method according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a shaft movement amount detection mechanism, 2 denotes a comparison mechanism that compares a commanded machining depth with the shaft movement amount from the shaft movement amount detection mechanism 1 and outputs a coincidence signal, 3
Includes a timer 3a used for determining the processing time and a timer 3b for counting the determined time, and a timer mechanism for outputting a coincidence signal when the determined processing time has elapsed.
Is a determination mechanism that switches or matches the coincidence signal from the comparison mechanism 2 and the coincidence signal from the timer mechanism 3 and outputs a machining end signal, and 5 is during actual machining in which electric discharge is performed with the workpiece, This is a machining-in-process discriminating mechanism for discriminating whether a non-machining process is in progress, such as during a jump operation.

Next, the operation will be described. When the actual machining time required for machining per unit area is specified, the timer mechanism 3 obtains the axis movement amount per unit time based on the axis movement amount from the axis movement amount detection mechanism 1. Further, a processing area for this processing is obtained from the axial movement amount and the processing speed per unit area based on the processing conditions at this time. Then, the actual processing time specified previously is multiplied by (processing area / unit area) to determine the processing time. The processing-in-process discriminating mechanism 5 outputs a signal to the timer mechanism 3 only during actual machining in which electric discharge occurs between the workpiece and the workpiece. The timer mechanism 3 counts only the actual machining time, and sends a coincidence signal to the determination mechanism 4 when the time coincides with the previously calculated determination time. Even if there is no coincidence signal from the comparing mechanism 2, the judging mechanism 4 sends a machining end signal by the logical sum with the coincidence signal from the timer mechanism 3, thereby ending the electric discharge machining.

FIG. 2 is a flowchart showing the operation of the timer mechanism 3. This processing is performed at regular time intervals, for example, 0.
This is a real-time process executed once every second. next,
This flowchart will be described in the order of steps. Step 1: It is checked whether or not the timers 3a and 3b have been initialized. If the timer has not been initialized, the process proceeds to step 2, and if the timer has been initialized, the process proceeds to step 4. Step 2: Read the processing speed per unit area (mm / min · cm ² ) of the specified time and the processing conditions at that time. Step 3: The timers 3a and 3b are cleared. Further, the movement amount of the axis at this time is read. Further, it is set to initialized ON. Step 4: It is determined from the signal from the processing determination mechanism 5 whether or not the actual processing is being performed. If the actual processing is being performed, the process proceeds to Step 5, and if not, the process is terminated. Step 5: Update the timers 3a and 3b (+1). A multiple of the cycle of this processing (for example, 0.1 second) is the value of the timer 3a and the timer 3b. Step 6: Check whether the machining time has been determined,
If it has been determined, the process proceeds to step 11, and if it has not been determined, the process proceeds to step 7. Step 7: The timer 3a for determining the processing time checks whether or not a predetermined time, for example, one minute, has elapsed. Step 8: The axis movement amount is read from the axis movement amount detection mechanism 1. Step 9: The processing time is determined by the following equation.

[0017]

(Equation 1)

Step 10: The processing time is determined and turned ON. Step 11: Timer 3b for judging the elapse of machining time
Is checked for the time determined in step 9. If the time has elapsed, the process proceeds to step 12, and if not, the process proceeds to the end. Step 12: Output a coincidence signal indicating the end of processing to the determination mechanism 4. Step 13: Turn off the initialization completed and turn off the processing time determined.

In the present embodiment, the coincidence signals from the comparison mechanism 2 and the timer mechanism 3 are processed by the logical sum in the judgment mechanism 4, but they may be selectively switched by the switching mechanism. Further, in the present embodiment, the actual machining time required for machining per unit area is specified in advance, but the actual machining time per unit area for obtaining a surface specific to the machining condition is not specified in advance. And the set time may be calculated from the actual processing time and the processing area.

[0020]

According to the first aspect of the present invention, the actual machining time is taken as the machining time, so that the set time itself is the discharge time between the workpiece and the workpiece, so that the more accurate machining shape can be obtained. Have.

According to the second aspect, the pre-specified machining time is corrected, and the optimum machining time is automatically determined.
According to the third aspect, the optimum machining time is automatically determined without designating the machining time, and each has an effect that an efficient and accurate machining shape can be obtained.

[Brief description of the drawings]

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

FIG. 2 is a flowchart showing the operation of the timer mechanism of FIG.

FIG. 3 is a configuration diagram illustrating a conventional machining end determination method.

[Explanation of symbols]

 1 axis movement amount detection mechanism 2 comparison mechanism 3 timer mechanism 4 determination mechanism 5 processing determination mechanism

Claims (3)

(57) [Claims] 1. A discharge machining method for determining the end of processing with the lapse of the set time, in discharge between the workpiece
By counting only the actual machining time of
An electric discharge machining method characterized by judging progress . 2. In an electric discharge machining method for judging the end of machining based on the elapse of a set time, a machining area is determined from an axial movement amount per unit time and machining conditions, and a ratio between the machining area and the unit area is designated in advance. The electric discharge machining method characterized in that a time obtained by multiplying the actual machining time per unit area is a set time. 3. In an electric discharge machining method for judging the end of machining based on the elapse of a set time, a machining area is obtained from an axial movement amount per unit time and machining conditions, and a surface unique to the machining area and machining conditions is obtained. An electric discharge machining method, wherein a set time is calculated from an actual machining time per unit area for use.