JPH06719A - Machining depth measuring device for electric discharge machine - Google Patents

Abstract

PURPOSE:To provide a machining depth measuring device for an electric discharge machine which can perform accurate measurement of the machining depth of a work and can be automated. CONSTITUTION:A conductive measuring probe 6 is elevatably held to a conductive holding body 5, attached to the head 3 of an electric discharge machine, through an insulating spacer 9. By further lowering the head 3 after the lower end of the measuring probe 6 is brought into contact with the surface to be machined of a work 4, the upper end of the measuring probe 6 is brought into contact with the under surface of the holding body 5 and the two members are electrically interconnected. This constitution prevents an adverse influence from being exercised on measurement of machining depth by sludge present in machining oil remaining on the machined surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machining depth measuring device for an electric discharge machine, and more particularly to a machining depth measuring device suitable for automatically measuring the machining depth of a workpiece.

[0002]

2. Description of the Related Art In electric discharge machining, a predetermined voltage is applied between an electrode and a workpiece in an insulating machining oil, and spark discharge generated at that time melts or vaporizes the workpiece. This is the method, and its application range has been greatly expanded in recent years, including the processing of molds.

In such electric discharge machining, it is necessary to measure the working depth of the work piece machined by the electrode, and the measuring depth is automatically measured by an ATC (automatic exchange device). Is proposed.

FIG. 2 is an explanatory view showing a conventional machining depth measuring device, in which 1 is a main body of an electric discharge machine and 2 is this main body 1.
Table 3 provided in the main body 1 is also provided in the main body 1. The table 2 is controlled to move in the horizontal direction (X-Y axis direction) and the head 3 is controlled to move in the vertical direction (Z axis direction). It has become. Reference numeral 4 denotes a work piece placed and fixed on the table 2, and 5 denotes a conductive holder attached to the lower surface of the head 3, and the holder 5 has a lower end formed in a needle shape. The conductive stylus 6 is fixed. Reference numeral 7 denotes an insulating processing oil, and 8 an ammeter. Both terminals of the ammeter 8 are connected to the table 2 and the head 3, respectively.

FIG. 2 shows a state after the electric discharge machining of the workpiece 4 into a predetermined shape by an electrode (not shown). That is, an electrode is attached to the head 3 instead of the holder 5, a predetermined voltage is applied between the electrode and the workpiece 4 in the insulating machining oil 7, and the table 2
By controlling the movement of the work piece 4 in the X-Y axis direction by the head 3 and by the head 3 in the Z axis direction by the head 3,
A recess 4a as shown in the drawing is processed in the workpiece 4. After that, using ATC, a holder 5 is attached to the head 3 instead of the electrode, the head 3 is lowered in the Z-axis direction, and the lower end of the probe 6 is abutted against the machined surface of the workpiece 4, and the table is Two
And the head 3 are electrically connected to the workpiece 4 via the probe 6 and the holding body 5, and by detecting this state with the ammeter 8, the descending amount of the head 3, that is, the processing of the workpiece 4 is performed. The depth can be measured.

[0006]

By the way, in the above-described conventional working depth measuring device, the probe 6 fixed to the holder 5 descends in the working oil 7 and the working surface of the work 4 is processed. Since the machining depth of the work piece 4 is actually measured by touching the work piece 4, sludge (dust) S generated from the work piece 4 or the electrode during the electric discharge machining may be mixed into the working oil 7. Then, before the contact point 6 contacts the machined surface of the workpiece 4, both of them are electrically conducted through the sludge S, which causes a problem that the machining depth cannot be accurately measured. If the sludge S is manually removed before measuring the working depth, the above problem can be solved, but in this case, the measurement cannot be completely automated and there is a problem in workability.

The present invention has been made in view of the above-mentioned prior art, and an object thereof is to accurately measure a working depth,
Another object of the present invention is to provide a machining depth measuring device for an electric discharge machine that can be automated.

[0008]

In order to achieve the above object, the present invention is provided between an electrode attached to a vertically movable head of a main body and a work piece arranged facing the electrode. In a machining depth measuring device of an electric discharge machine for generating a spark discharge and measuring a machining depth of the workpiece machined by the spark discharge, a conductive holder attached to the head and the holding A conductive probe that is held in the body so that it can be moved up and down through an insulator, and a spring that urges the probe in the processing surface direction of the workpiece, and the holder and the probe It is characterized in that a gap for switching contacts is formed between them.

[0009]

When the head is lowered with respect to the work piece after electric discharge machining, the probe descends in the machining oil and hits the machining surface of the work piece. Even if it is interposed between the processing surface and the processing surface, the holding body and the measuring element are kept in a non-conductive state. When the head is further lowered after the probe contacts the machined surface, the probe moves relatively upward in the direction of the head against the elasticity of the spring, and the probe contacts the holder. Therefore, by detecting this using an ammeter or the like, it is possible to accurately measure the descending amount of the head, in other words, the working depth of the workpiece.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing a machining depth measuring device of an electric discharge machine according to an embodiment of the present invention, and the portions corresponding to those in FIG.

The machining depth measuring apparatus according to this embodiment is different from the above-mentioned conventional example in that the probe 6 is supported by the holder 5 so as to be movable up and down, and a gap G for switching contacts is formed between the two. However, the rest of the basic configuration is the same. That is, the retainer 10 is fixed to the lower surface of the holding body 5 via the spacer 9 made of an insulating material such as ceramics, and the tracing stylus 6 is attached to the spacer 9 and the linear ball guide 11 provided inside the retainer 10. It is guided in the vertical direction, and is prevented from falling off from the retainer 10 by the collar portion 6a. Also, the linear ball guide 11
A spring 12 is provided between the measuring element 6 and the collar portion 6a, and the measuring element 6 is elastically biased by the spring 12 in a direction away from the holding body 5. Normally, the upper end of the measuring element 6 and the holding element 5 are A predetermined gap G is formed between the lower surface and the lower surface.

When the machining depth of the workpiece 4 is measured by the measuring device having the above-described structure, the recess 4a is formed in the workpiece 4 by the electric discharge machining using an electrode (not shown) as in the conventional example described above. Then, using ATC, a measuring device including a holder 5 is attached to the head 3 instead of the electrode. Then, the head 3 is driven in the Z-axis direction to lower the tracing stylus 6, and the lower end of the tracing stylus 6 is brought into contact with the machined surface of the workpiece 4. During this time, the tracing stylus 6 receives a spring force from the spring 12 and is urged downward, and the gap G is kept constant. Therefore, the sludge S existing in the processing oil 7 remaining on the processing surface causes the holder 5 to move. And the probe 6 are not electrically connected.

When the head 6 hits the surface to be machined, it does not descend further, so that the holding body 5, the spacer 9, the retainer 10 and the linear ball guide 11 descend while compressing the spring 12 by the further lowering of the head 3, and the gap The amount of G gradually decreases, and finally the upper end of the probe 6 contacts the lower surface of the holder 5. As a result, the table 2 and the head 3 are electrically connected to each other via the workpiece 4, the probe 6, and the holder 5, and when this state is detected by the ammeter 8, the workpiece 4 is determined based on the descending amount of the head 3. The processing depth of can be measured.

The means for insulating the holding body 5 and the tracing stylus 6 is not limited to the above embodiment. For example, it is possible to omit the spacer 9 and form the retainer 10 itself with an insulating material. It suffices that the tracing stylus 6 is held so as to be able to come into contact with and separate from the holder 5 via an insulator.

[0015]

As described above, according to the present invention,
Since the gap for contact switching is formed between the holder attached to the head and the probe held by the holder so as to be able to move up and down, it is possible to accurately measure the machining depth without being affected by the atmosphere of the machining surface. And the measurement can be automated.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a machining depth measuring device of an electric discharge machine according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing a machining depth measuring device of an electric discharge machine according to a conventional example.

[Explanation of symbols]

 1 Main Body 2 Table 3 Head 4 Workpiece 4a Recess 5 Retainer 6 Measuring Element 6a Collar 7 Machining Oil 8 Ammeter 9 Spacer (Insulator) 10 Retainer 11 Linear Ball Guide 12 Spring G Gap S Sludge

Claims (1)

[Claims] 1. A spark discharge is generated between an electrode attached to an ascendable / descendable head of a main body and a work piece arranged facing the electrode, and the work piece processed by the spark discharge is generated. In a machining depth measuring device of an electric discharge machine for measuring a machining depth of an object, a conductive holder attached to the head and a conductive holder held by the holder via an insulator so as to be capable of moving up and down. An electric discharge comprising a measuring element and a spring for urging the measuring element in the processing surface direction of the workpiece, and forming a contact switching gap between the holder and the measuring element. Processing depth measuring device for processing machines.