JPS6154529B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wire cut electric discharge machining method, and particularly to an improvement in the wire electrode automatic insertion method.

The inventor of the present invention has filed Japanese Patent Application No. 54-85060.
9134) disclosed a wire cut electric discharge machining device equipped with an automatic wire electrode insertion device. This automatic insertion device has an electrode insertion guide arm that can be raised and lowered and has a guide hole through which a wire electrode is inserted close to the upper or lower surface of the workpiece, and a surface of the workpiece opposite to the guide arm. The device consists of a wire electrode cutting device that can cut the wire electrode at a position close to the wire electrode, and a wire electrode retracting device that can pull in the tip of the wire electrode inserted into the workpiece, and the wire electrode is connected to the guide of the guide arm. The wire electrode is collected through the hole, through the processing section of the workpiece, and through the inside of the cutting device. After processing, the wire electrode is heated and hardened in the axial direction, and then the wire electrode is cut. The workpiece is cut by the device and pulled out from the hole of the contoured workpiece while being inserted into the guide hole of the guide arm. After the workpiece is moved or replaced, the workpiece is removed by the guide arm. The material was inserted into a new processing hole, pulled in by a pulling device, and sent to a recovery device for the next processing.

If the wire electrode is completely straight after being cut, the hole to be drilled in advance in the workpiece can be small, and insertion will not fail. In the method and apparatus described in No. 54-85060, the linearity of the wire electrode after cutting was not necessarily sufficient.

One of the reasons why the linearity of the wire electrode is lost when it is cut after being heated and cured with electricity is that when the wire electrode is heated and cured with electricity after processing, the workpiece may not be processed properly. This is because the machining liquid or the like is non-uniformly attached to the surface of the wire electrode in the area, so that uniform heating is not performed and the wire electrode is bent to some extent in this area.
When a thin wire electrode is bent, the function of the automatic wire electrode insertion device often stops, and a large amount of manual labor is required to restore the function.

An object of the present invention is to provide a method for cutting and inserting a wire electrode in a processing portion of a workpiece without impairing the linearity of the wire electrode when cutting the wire electrode as described above.

Therefore, the gist of the present invention is that when the wire electrode is energized to heat and harden after processing and is then cut, the part facing the workpiece is cut before the energization and heating. A gas such as compressed air is blown onto the wire electrode in the processing area near the wire electrode to remove the processing fluid and other deposits adhering to the wire electrode in advance.

In this way, unlike conventional methods, the wire electrode in the processing portion of the workpiece is cut while maintaining its straightness without bending.

For this reason, the functions of the wire electrode automatic insertion device are fully utilized, and the prepared hole for machining can be made small, so that the machining time is significantly shortened overall.

Hereinafter, the details of the present invention will be specifically explained with reference to the drawings.

The drawing is an explanatory view showing an example of an apparatus used to carry out the automatic wire electrode insertion method according to the present invention.

In the drawing, 1 is a wire electrode power supply drum, 2 is a brake roller, 3, 4, 5 are guide rollers, 6 is a current-carrying roller, 7, 10 are capstans, 8, 11 are pinch rollers, 9, 12 are boat-shaped guides, etc. 13 is a machining fluid jet nozzle, 14 is a machining fluid supply pipe, 15 is a wire electrode, 16 is a wire electrode cutting device, 17 is a workpiece, 18 is a guide arm, 19 is a stage, 20 and 21 are 22 is a lower arm, 23 is a compressed air injector, and 24 is a compressor.

During electric discharge machining, the wire electrode 15 is pulled out from the electrode supply drum 1 at a constant speed by the capstan 10 and the pinch roller 11, passes through rollers 2 to 6, and is delivered to the machining part where the workpiece 17 is placed. Supplied. In the processing part, the wire electrode 15
is stretched linearly between the boat-shaped guides 9 and 12 with a constant tension, and discharges between the workpiece 17 and the electric discharge voltage applied between the energizing roller 6 and the workpiece 17. . The workpiece 17 is moved in a direction perpendicular to the electrode tensioning direction by driving the cross tables 20 and 21 using an NC device, and is processed in accordance with a desired processing contour.
In addition, a machining fluid jet nozzle 1 is installed in this machining part in order to remove machining debris and smooth the discharge.
Processing fluid is supplied from 3. Therefore, when automatically inserting an electrode with this device, the wire electrode 15 in the processing part of the workpiece 17 is inserted before cutting the wire electrode.
Next, compressed air from the compressor 24 is injected by the compressed air injector 23 to remove the liquid adhering to the wire electrode. After removal, the wire electrode 15 is heated and hardened by passing a current sufficient to heat and harden the wire electrode 15. Thereafter, the cutting device 16 is operated to cut the wire electrode 15 below the workpiece 17. Note that the compressor 24 may be of any type as long as it can generate compressed air necessary to remove deposits from the wire electrodes.

By using the above-mentioned device, all machining liquid and other deposits adhering to the wire electrode in the machining part of the workpiece are removed, and then the wire electrode is energized to remove it. Since it is heated and hardened, the wire electrode is heated evenly and can be cut without losing its straightness. After cutting, the head is raised and lowered while grasping the wire electrode 15 on the workpiece 17, and the workpiece 17 is aligned by controlling the movement of the tables 20 and 21, so that the prepared hole of the next workpiece is aligned with the wire electrode axis. When the wire is directly below the hole, the head is lowered to insert the wire into the prepared hole. Since the tip of the wire electrode 15 maintains a straight line as described above, it can be easily inserted. drive it.

Note that the method of the present invention is not limited to the above-mentioned embodiments. Thus, for example, the compressed air injector may be controlled manually or by voltage from a control circuit. It is also possible to use inert gas contained in a cylinder without using a compressor, and the present invention encompasses all of them.

[Brief explanation of the drawing]

The drawing is an explanatory view showing an example of an apparatus used to carry out the automatic wire electrode insertion method according to the present invention. 1... Wire electrode supply drum, 2... Brake roller, 3, 4, 5... Guide roller, 6... Current roller, 7, 10... Capstan, 8, 11
... Pinch roller, 9, 12 ... Boat-shaped guide, 1
3... Machining fluid ejection nozzle, 14... Machining fluid supply pipe, 15... Wire electrode, 16... Wire electrode cutting device, 17... Workpiece, 17a... Prepared hole for processing, 18... Guide arm , 19... loading table,
20, 21...Cross slide table, 22...
... lower arm, 23 ... compressed air injector, 24 ...
...compressor.

Claims (1)

[Scope of Claims] 1. A method for automatically inserting a wire electrode of a wire cut electric discharge machining device into a machining hole of a workpiece, the wire electrode comprising the steps described in the following items a to g. Automatic insertion method. a. A step of cutting off the discharge current between the workpiece and the wire electrode and simultaneously stopping the feeding of the wire electrode at the time when the machining of one machining shape on the workpiece is completed. b. A step in which compressed gas is sprayed onto the wire electrode stationary in the processing area to remove processing fluid and other deposits adhering to the wire electrode. c. A step of passing sufficient current to heat and harden the wire electrode through the straight portion of the wire electrode that is stationary in the processing area. d. Cutting the wire electrode above or below the workpiece. e. A process of moving the processing head in the axial direction of the wire electrode in the processing section in order to separate the straight wire electrode left at the tip of the wire electrode feeding side from the workpiece. f. A step of moving the workpiece or the processing head so that the next machining hole of the workpiece comes to a position opposite to the tip of the straight wire electrode. g. A step of moving the processing head in the axial direction of the electrode in order to insert the linear wire electrode into the processing hole.