JPH04201120A - Wire electric discharge machining method - Google Patents

Abstract

PURPOSE:To prevent securely wire electrode from being broken by discriminat ing the run-up machining of a work to be machined by NC program and, when completion of run-up machining is discriminated, starting machining of the work to be machined in ordinary electrical conditions. CONSTITUTION:When an NC program is started by a run-up machining condition control device 12, the NC program is read out for each block from a memory 2 by a read-out analyzer 3 to separate and analyze electrical condition commands, etc., such as moving commands, etc. Then, when one block of the read out NC programs is discriminated as for run-up machining of a work to be machined, the control device 12 is operated to give a command to a power control device 6. And it is judged whether the run-up machining is completed or not and, when its completion is discriminated, machining is started in ordinary machining conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a wire electrical discharge machining method that improves initial machining performance when machining a workpiece using a wire electrical discharge machining device.

[Prior Art] A wire electrical discharge machining method using a conventional wire electrical discharge machining apparatus will be described with reference to the drawings. FIG. 4 is a diagram for explaining the conceptual configuration of a conventional wire electric discharge machining apparatus. In the figure, 1 is an input/output device for NC data, and the NC data includes movement commands, etc., which are instructions for controlling the relative movement of the wire electrode and the workpiece in the wire electric discharge machining device, and the wire electrode and workpiece. There is an NC program created with electrical condition commands, etc. to the power source that applies voltage between the objects. 62 is a memory for storing NC data etc. from the NC data input/output device 1, and 3 is a memory 2. 4 is an NC data reading/analyzing device for reading and analyzing the NC data stored in the reading/analyzing device 3; 4 is an analyzing device for extracting only electrical condition commands from the results analyzed by the reading/analyzing device 3; and 5 is an analyzing device for analyzing the electrical conditions; This is a setting device that sets various conditions during machining, and is used to manually set electrical conditions when you want to change the electrical conditions during machining. 6 is a power supply control device that controls a power source that applies a voltage between the wire electrode and the workpiece based on the electrical conditions analyzed by the analysis device 4;
8 is a numerical calculation device that numerically calculates movement commands, machining commands, etc. in NC data from the results analyzed by the reading/analysis device 3; 8 is an axis movement interpolation device;
In order to perform relative movement between the wire electrode and the workpiece based on the movement command etc. calculated by It is sent to the power supply in accordance with movement interpolation.

9 performs relative movement between the wire electrode and the workpiece and generates electric discharge according to the data given by minute line segments and electrical conditions, and also performs the relative movement between the wire electrode and the workpiece according to the commands from the axis movement interpolation device 8. This is a servo device that processes the workpiece while sensing the voltage between the electrodes. Reference numeral 10 denotes a CRT device that displays the processing status of the workpiece, set values such as movement commands and electrical conditions, and data indicating the position of axis movement accompanying relative movement of the wire electrode and the workpiece. It is. 11
is an electrical condition package memory that stores multiple electrical conditions as a package, such as the voltage, current, pause time, tension of the wire electrode, and feeding speed of the wire electrode between the wire electrode and the workpiece. It stores a plurality of packages, and the electrical condition package corresponding to the electrical condition command analyzed by the analyzer 4 is read out. Conditions are set and changed.

Next, a wire electrical discharge machining method using this conventional apparatus will be explained. First, in the conventional device shown in FIG.
When the NC program is started, the read/analyzer 3 reads out the NC program block by block from the memory 2, separates movement commands, electrical condition commands, etc., and analyzes them. If one block of the read NC program is a movement command, the numerical calculation unit 7 calculates the movement vector of that block. Also, in the case of electrical condition instructions,
The analysis device 4 analyzes the electrical condition command, extracts the corresponding electrical conditions from among the electrical conditions stored in the memory 11 of the electrical condition package based on the analysis result, and sends the extracted electrical conditions to the control device 6. Output and change electrical conditions. Note that when the operator is monitoring the machining status and needs to change the electrical conditions, when the operator operates the setting device 5 to change the electrical conditions, an interrupt-like process is performed.
The analysis device 4 outputs the changed electrical conditions to the control device 6 to change the electrical conditions. Next, based on the movement vector calculated by the numerical calculation device 7 and the electrical conditions applied to the control device 6, the axis movement interpolation device 8 performs interpolation for relative movement between the wire electrode and the workpiece. The data of the minute line segment of the axis and the electrical conditions corresponding thereto are output to the servo device 9. Then, the servo device 9 moves the wire electrode and the workpiece relative to each other and generates a discharge based on the data given by the minute line segment and the electrical conditions, and also performs the voltage between the wire electrode and the workpiece. Machining the workpiece while sensing the As a result, the workpiece is processed. Note that the CRT device 10 displays the processing position of the workpiece as the processing progresses.

[Problems to be solved by the invention] In such wire electric discharge machining, as shown in FIG.
When performing machining, the machining start hole 102 of the workpiece 100 is
A wire electrode (not shown) is inserted into the wire electrode to connect the wire electrode, and a run-up trajectory 1 for machining the workpiece 100 is created.
After the run-up machining of 04, the original machining trajectory 106 is machined. The original machining trajectory 106 may be machined multiple times by switching the electrical conditions depending on rough machining or finishing machining, etc., and the first machining is called a first cut (referred to as 1st second), and the second machining is The second cut and third processing are called the third cut. Such wire electrode connection work, run-up trajectory 104,
The machining trajectory 106 is programmed as an NC program, and the number of times the machining trajectory 106 is to be machined, the electrical conditions under which the machining is to be performed, etc. are programmed as an NC program.

By the way, in wire electric discharge machining, when machining the workpiece 100 from the machining start hole 102, electric discharge starts from a state where there is no electric discharge at all, and this initial machining process called biting machining is performed.5) Since the machining is not stable in this case, it is necessary to perform zero-force machining on the approach path 104 under machining electrical conditions different from the original machining path 106. Therefore, in the conventional wire electric discharge machining method, it is necessary to program the electrical conditions for the run-up machining of the run-up locus 104 and the run-up locus in the NC program.

For this reason, it is necessary to create a program for run-up machining every time an NC program is created, and the work of creating an NC program becomes complicated. Because the electrical conditions for run-up machining were not appropriate due to the creation of an incorrect program for run-up machining, there were problems such as frequent disconnection of the wire electrode.

This invention was made to solve the above-mentioned problems, and it is easy to create an NC program, and
It is an object of the present invention to provide a wire electrical discharge machining method that does not cause disconnection of a wire electrode during initial machining.

[Means for Solving the Problems] A wire electrical discharge machining method according to the present invention includes the following steps:
The step of determining from the NC program that the workpiece is being run-up machining, If it is determined that it is run-up machining, the step of setting the run-up machining conditions and performing the run-up machining of the workpiece under these machining conditions. A step of determining whether or not run-up machining has been completed during machining under machining conditions, and a step of starting machining of a workpiece under normal electrical conditions when it is determined that run-up machining has been completed. Features.

[Function] In the wire electrical discharge machining method according to the present invention, in wire electrical discharge machining, it is automatically determined from the NC program that it is run-up machining, and machining is performed under the machining conditions for run-up, and when the run-up machining is finished, Electrical discharge machining is now performed under normal electrical conditions.

[Embodiment of the Invention] Hereinafter, an embodiment of the wire electrical discharge machining method according to the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of a wire electrical discharge machining apparatus for explaining an embodiment of the wire electrical discharge machining method according to the present invention, and FIGS. 2 and 3 show an example of the wire electrical discharge machining method according to the present invention. It is a flowchart for explaining an example.

In FIG. 1, reference numeral 12 is a machining condition control device during run-up machining. When the NC program is started, the reading/analysis device 3 reads out the NC program block by block from the memory 2, and controls electrical conditions such as movement commands. Once instructions etc. are separated and analyzed, the read NC
It is activated when it is determined that one block of the program is run-up machining of the workpiece, and gives a command to the power supply control device 6. Reference numerals 1 to 11 indicate parts corresponding to those of the conventional device shown in FIG. 4, and the explanation thereof will be omitted.

In the wire electrical discharge machining method according to this embodiment, first, the
When the program is started, the read/analyzer 3 reads out the NC program block by block from the memory 2, separates movement commands, electrical condition commands, etc., and analyzes them (SL). Then, it is determined whether one block of the read NC program is a connection instruction for connecting a wire electrode to a workpiece (S2). Next, if it is a wiring instruction, it is determined whether or not it is the 1st cut (S3), and when it is the 1st cut, the NC program is read (S3).
4) Search for the next axis movement command, and if the command is a machining command, the control device 12 is activated. That is, it is determined here that the run-up machining of the workpiece is being performed.

The control device 12 sets the run-up machining conditions.
6) Output to the power supply control device 6, and perform run-up machining of the workpiece under these machining conditions. Note that the machining conditions for run-up may be stored in the memory 11 of the electrical condition package.

Then, it is determined whether the run-up machining has ended or not (S7), and when it is determined that the run-up machining has ended, machining is started under normal machining conditions (S8). When the run-up machining is completed, machining of the workpiece is started under normal electrical conditions based on a command from the analysis device 4, and the operation at this time is the same as the conventional one. Note that other operations are similar to those of the conventional device.

Next, regarding determination as to whether or not the run-up machining has ended, a sequence for determining the run-up machining based on the run-up machining distance will be described using the flowchart of FIG.

At this time, the machining conditions for the run-up are set and the workpiece is being machined (S6).Then, first, it is determined whether or not the run-up distance has been set by the setting device 5 (S6).
ll). Next, if the run-up distance has been set, it is determined whether or not the set value 5 is greater than the moving distance of one block read as the NC program (S L2). Subsequently, if the set value is small, the set value is set as the run-up moving distance for run-up machining (513), and if it is large, the moving distance of one block is set as the run-up distance (S14).

Next, a case where the approach distance is not set by the setting device 5 will be described. In this case, the numerical control device has a predetermined value, and this value is compared with the moving distance of one block read as the NC program (S
15). If the specified value is smaller than the moving distance of one block, run-up processing is performed using the specified value as the run-up distance (
S16), if it is larger, the moving distance of one block is set as the run-up distance (517).

In this way, the machining distance for the run-up machining is determined, and it is determined whether the run-up machining is finished.

After that, before returning to the normal electrical conditions and machining the workpiece, turn off the power for a few seconds to prevent the wire electrode from breaking when changing the machining conditions.
(S18), and then switching to normal electrical conditions and restarting machining (S8).

In this way, run-up machining can be performed reliably.

In this embodiment, the NC program determines whether the workpiece is being run-up by using the wire electrode connection command and whether or not the 1st cut has been made. The present invention is not limited to this, and a command or a mark indicating run-up machining may be added to the NC program.

[Effects] In the wire electric discharge machining method according to the present invention, the step of determining from the NC program that the workpiece is run-up machining;
If it is determined that it is run-up machining, set the run-up machining conditions and perform run-up machining of the workpiece under these machining conditions, and determine whether run-up machining has finished during machining using the run-up machining conditions. and a stage to start machining the workpiece under normal electrical conditions when it is determined that run-up machining has been completed. In addition to machining under the following machining conditions, once run-up machining is completed, electrical discharge machining is performed under normal electrical conditions.This makes it possible to reliably prevent the wire's electrode from breaking during initial machining, and also to ensure that the NC program can be easily created and has the effect of significantly improving automation.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of a wire electrical discharge machining apparatus for explaining the wire electrical discharge machining method according to the present invention, and FIG.
3 and 3 are flowcharts for explaining an embodiment of the wire electrical discharge machining method according to the present invention, and FIG.
FIG. 5 is a diagram showing a schematic configuration of a wire electrical discharge machining apparatus for explaining a conventional wire electrical discharge machining method, and is a diagram for explaining a machining locus of wire electrical discharge machining. In the figure, 1 is an NC data input/output device, 2 is a memory, and 3 is an N
C data reading/analysis device, 4 electrical condition command analysis device, 6 power supply control device, 7 numerical calculation device such as movement commands, 8 axis movement interpolation device, 9 servo device, 10 C
It is an RT device. In addition, the same reference numerals are attached to the same parts and corresponding parts in the figures.

Claims (1)

[Claims] (1) In a wire electrical discharge machining method in which electric discharge is generated between a workpiece and a wire electrode based on an NC program and the workpiece is machined, it is determined from the NC program that the workpiece is run-up machining. A step of determining: If it is determined that it is the run-up machining described above, a step of setting the run-up machining conditions and performing run-up machining of the workpiece under these machining conditions; Run-up machining is completed during machining with the above run-up machining conditions. a step of determining whether the run-up machining has been completed; and a step of starting machining of the workpiece under normal electrical conditions when it is determined that the run-up machining has been completed.