JPH0822484B2 - Automatic insertion method of wire electrode - Google Patents

Description

The present invention relates to a method for automatically inserting a wire electrode used in a wire cut electric discharge machine.

(Prior Art) A wire-cut electric discharge machine requires a wire electrode to be inserted into a machining start hole of a work piece at the start of machining, and when the wire electrode is cut during machining, the wire is cut on the work piece. Often, the electrode must be inserted. When such a demand arises, various methods for automatically inserting the wire electrode into the workpiece have been proposed from the viewpoint of labor saving and automation.

The method most often used for such purpose is to feed the wire electrode from one positioning guide to the other corresponding positioning guide at a constant speed by a driving device such as a roller.

(Problems to be Solved by the Invention) In the case of the above-mentioned conventional method, even if the linearity of the wire electrode is maintained by an appropriate means, the hole provided in the workpiece has a small diameter, or When the roughness of the inner surface is large, the tip of the wire electrode cannot smoothly pass through the hole, the wire electrode is caught at the entrance or the middle of the hole, and the wire electrode tends to buckle. Therefore, there is a problem that automatic wire connection of the wire cut electric discharge machine cannot be performed with high reliability.

An object of the present invention is to provide a highly reliable method of automatically inserting a wire electrode that can reliably perform automatic insertion of a wire electrode.

(Means for Solving the Problem) A feature of the method of the present invention for solving the above-mentioned problem is that an inlet of a predetermined space such as a hole or a groove formed in a workpiece or the like by a tip of a wire electrode by a pipe guide. In the automatic insertion method of the wire electrode in which the tip of the wire electrode is inserted into the space from the outlet end of the pipe guide, the tip portion of the wire electrode in a restrained state is inserted. A liquid column having a steady velocity distribution state is formed in the space by pumping the liquid into the pipe guide and injecting the liquid into the space from the outlet end of the pipe guide. By releasing the restraint state of the wire electrode in a slackened state, the tip of the wire electrode is discharged from the space by the liquid flowing in the pipe guide and the space. It is in the point that I tried to lead to.

(Operation) When the tip of the wire electrode is inserted into the pipe guide while the wire electrode is restrained and the liquid is pumped to the pipe guide, thrust is applied to the wire electrode but the wire electrode remains stopped. In, good linearity is maintained.
In this state, if a liquid column with a steady velocity distribution is formed in the space and the restraint is released with the wire electrode having slack, the tip of the wire electrode will lose its linearity due to the thrust acting on it. While maintaining the above, the liquid enters into the space, and tries to pass through the portion having the highest flow velocity in the liquid column formed therein, that is, the central portion in the space. In this case, since the wire electrode has a predetermined slack, the wire electrode can smoothly move in the space due to the flow of the liquid, and the tip of the wire electrode can be kept in the space while maintaining its linearity. It is possible to effectively prevent the distal end of the wire electrode from passing through the central portion and being locked to the edge portion of the entrance and the inner peripheral wall, and the wire electrode can be reliably and automatically inserted into the required space.

Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an embodiment of an automatic insertion device for automatically inserting a wire electrode for wire-cut electric discharge machining into a machining start hole provided in a workpiece using the method of the present invention. ing. The automatic insertion device 1 has a wire electrode feeding device 3 having a pair of rollers 3a and 3b for feeding the wire electrode 2, a buckling sensor 4 and a pipe guide 5. The wire electrode feeding device 3 is a device for advancing and retracting the wire electrode 2 toward or away from the workpiece 6, and the wire electrode 2 fed by the wire electrode feeding device 3 buckles. It is guided by the pipe guide 5 through the sensor 4 and reaches the processing start hole 6a of the workpiece 6.

At this time, the central axis of the pipe portion 5a of the pipe guide 5 is relatively positioned by a movement control device (not shown) so as to coincide with the axis of the processing start hole 6a which is a through hole. Therefore, the tip 2a of the wire electrode 2 is
It enters into 6a and is discharged from its exit end 6b. Exit end 6b
The tip 2a discharged from is grasped by a device (not shown) and sent to the wire electrode winding device.

It is to be noted that the reference numeral 7 is a split guide, and after the wire electrode 2 is inserted into the processing start hole 6a, the pipe guide is brought to a position where it does not interfere with the split guide 7 being brought into a predetermined wire electrode guiding state. After 5 is moved, the split guide 7 is brought into a predetermined wire electrode guide state for guiding the wire electrode 2.

The operation described in FIG. 1 is the conventional wire electrode automatic insertion method using the pipe guide 5. This device 1
As shown in FIG. 2 during the automatic insertion operation based on FIG. 1, when the tip 2a of the wire electrode 2 is caught and buckled at the entrance end of the processing start hole 6a, the wire electrode 2 is automatically moved by the method of the present invention. It is configured to execute insertion.

As shown in FIG. 2, when the wire electrode 2 is buckled due to being caught, this state is detected by the buckling sensor 4, and thereby the automatic insertion operation by the automatic insertion method of the present invention is executed.

When the buckling of the wire electrode 2 is detected, as shown in FIG. 3, the pair of rollers 3a, 3b of the wire electrode feeding device 3 are
Rotates in the opposite direction, and the wire electrode 2 retracts once.

After that, as shown in FIG. 4, the pair of rollers 3a and 3b of the wire electrode feeding device 3 are separated from each other, the restraint on the wire electrode 2 is released, and the wire electrode 2 is in a sufficiently slack state to be in a free state. . The machining fluid is supplied to the machining fluid injection part 5b of the pipe guide 5 from a machining fluid tank (not shown), and the machining fluid injected from the machining fluid injection part 5b is supplied to the pipe portion 5a.
Through the pipe portion 5a toward the processing start hole 6a.

FIG. 5 schematically shows the state of the liquid column formed in the processing start hole 6a at this time. In the state shown in FIG. 4, the lower end of the pipe portion 5a is close to the processing start hole 6a,
A part of the working fluid 8 discharged from the pipe portion 5a is the work piece 6
Although it escapes to the upper surface of the column, most of it flows into the processing start hole 6a and forms a liquid column in a steady velocity distribution state here. As described above, in such a liquid column, the flow velocity in the central passage C is the fastest.

Therefore, the wire electrode 2 in a sufficiently slack free state is lowered toward the machining start hole 6a with the flow of the machining fluid due to the frictional force generated between the wire electrode 2 and the machining fluid flowing in the pipe guide 5. The tip 2a reaches near the processing start hole 6a,
The tip 2a enters into the above-mentioned liquid column formed there. The flow velocity distribution in the liquid column is as described above, and the tip 2a of the wire electrode 2 in a free state is drawn into the portion having the highest flow velocity. As a result, the tip 2a reaches the outlet end 6b through the central passage C in the processing start hole 6a, so that the tip 2a does not get caught on the inner wall of the processing start hole 6a and the wire electrode 2 is processed very smoothly. It can be automatically inserted into the start hole 6a.

In the illustrated embodiment, the case of automatic insertion into the processing start hole has been described, but the method of the present invention is not limited to this, and it can be used to pass a wire electrode through any other hole, groove, or the like. Of course.

Further, in the above-mentioned embodiment, the case where the method of the present invention is used when the conventional automatic insertion by the roller feed fails is described, but, of course, the automatic insertion of the wire electrode is performed from the beginning by the method of the present invention. The configuration may be performed.

Further, the lower wire guide may have both a split shape and a round die, but in the case of the round die, the wire electrode can be inserted into the die hole by the above-described action.

(Effect of the Invention) According to the present invention, as described above, the tip portion of the wire electrode is guided to near the entrance of the space to be inserted by the pipe guide, and the force of the liquid flowing in the pipe guide is used. In the method of inserting the tip of the wire electrode into the space from the outlet of the pipe guide, the liquid is caused to flow in the pipe guide in a restrained state with a slack in the wire electrode guided to the vicinity of the inlet of the required space. By applying a propulsive force to the wire electrode while maintaining the linearity of the tip of the wire electrode, the restraint state of the wire electrode is released in the state where a liquid column with a steady velocity distribution state is formed in the space. Since the wire electrode is made to pass through substantially the center of the space all at once while maintaining the linearity of the wire electrode, the wire electrode can be surely inserted automatically, and the reliability is remarkably improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram showing a state in which a roller electrode inserting operation of a wire electrode by the apparatus of FIG. 1 has failed, FIG. 3 and FIG. FIG. 5 is an explanatory diagram for explaining the operation of the wire electrode automatic insertion operation according to the method of the present invention, and FIG. 5 is a diagram schematically showing a state of a liquid column formed in the processing start hole. 1 ... Automatic insertion device, 2 ... Wire electrode 2a ... Tip, 6 ... Workpiece, 6a ... Machining start hole, 6b ... Exit end, 8 ... Working fluid.

Claims (1)

[Claims] 1. A pipe guide guides the tip of a wire electrode to the vicinity of the entrance of a predetermined space such as a hole or groove formed in a workpiece or the like, and thereafter, the tip of the wire electrode is guided by the pipe guide. In the automatic insertion method of the wire electrode which is inserted from the outlet end of the wire electrode into the space, the liquid is pressure-fed into the pipe guide in which the distal end portion of the wire electrode in a restrained state is inserted, and the liquid is discharged from the outlet end of the pipe guide. By injecting a liquid into the space, a liquid column with a steady velocity distribution state is formed in the space,
Then, by releasing the restrained state of the wire electrode in a state where the wire electrode has a slack, the tip of the wire electrode is guided to the outlet of the space by the liquid flowing in the pipe guide and the space. A method for automatically inserting a wire electrode.