JPH0464807B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an electric discharge machining apparatus, and in particular, a tape electrode is installed along the surface of an electrode guide that faces a workpiece with a predetermined machining gap maintained. , mesh electrode,
The present invention relates to an electric discharge machining apparatus that performs machining by stretching and renewing running of elongated electrode bodies such as wire electrodes.

[Prior art and its problems]

Unlike normal machining, which performs machining by directly applying mechanical force to the workpiece, electrical discharge machining equipment applies intermittent voltage pulses between the workpiece and electrodes to machine the workpiece. Since this is non-contact machining that utilizes electrical discharge erosion that occurs on the body surface, any complex or minute shape can be machined as long as the workpiece is made of conductive material, regardless of its hardness or toughness. It has the advantage of being able to Furthermore, since the force applied to the workpiece is significantly smaller than that in machining, it is possible to easily process thin plates, tubes, or thin wires.

Therefore, normally, in electrical discharge machining equipment, during electrical discharge machining, the workpiece and the electrode are machined in opposing directions, such as up and down, to prevent abnormal arc discharge etc. from occurring between the electrode and the workpiece. Movement such as feeding is configured to be controlled by a servo control device, except for control of the feed limit by a numerical control device or the like.

However, there is a problem in that the electrodes are inevitably worn out due to electrical discharge, and in some cases, the electrodes are not processed and fed properly, resulting in abnormal wear of the expensive electrodes.

Particularly, in the case of large die-cut electrodes, there are problems such as the replacement of worn out electrodes requires a great deal of cost and effort.

In order to solve the above problem, an electrode guide is provided which has a forming surface according to a desired processing shape and is arranged such that the forming surface faces the workpiece, and the forming surface of the guide is provided. tape electrode, mesh electrode,
For example, an electrical discharge machining device configured to carry out electrical discharge machining by running a long, thin and bendable electrode body such as a wire electrode in close contact with each other, and to sequentially collect or dispose of the worn-out electrode body after use is disclosed in Japanese Patent Application Laid-open No. 56
It was developed as described in Publication No. 45328 and Japanese Patent Application No. 70105/1985, etc., and as a result, it has become possible to perform long-term processing without substantially deforming the electrode guide through wear and tear. Ta. When the processed shape is not so complicated, it has also been proposed to use a pulley as the electrode guide.

However, as mentioned above, even in electrical discharge machining equipment that uses pulleys as electrode guides, it is necessary to replace the pulleys during machining depending on the shape to be machined, the purpose of machining, etc. There was a problem in that the work was time-consuming and the tensioning of tape electrodes and the like and the positioning and arrangement of pulleys after replacement were complicated.

[Object of the present invention]

The present invention has been made in order to solve the above-mentioned problems, and its purpose is to provide an electric discharge machining apparatus that can continue machining while automatically replacing the pulley as the electrode guide. It is about providing.

[Means for solving problems]

Therefore, the above purpose is to provide a plurality of electrode guide pulleys each having a different radius, and to
An electrode that selects the necessary pulleys from among the plurality of pulleys according to the machining shape in a desired order according to a predetermined program, etc. as necessary, and sequentially faces the machining part of the workpiece. This is achieved by providing a guide pulley changing device.

The replacement of the electrode guide pulley may be controlled in conjunction with the machining feed by a numerical control device that controls the machining feed of the dimensions, shape, etc. between the electrode guide pulley and the workpiece. is recommended.

[Effect]

With the above configuration, the electrode guide pulley can be automatically replaced depending on the machining shape, the purpose of machining, etc., thereby improving the machining efficiency.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described in detail below with reference to an embodiment of an electrical discharge machining apparatus according to the present invention shown in the drawings.

FIG. 1 is an explanatory diagram showing the main parts of an embodiment of the electrical discharge machining apparatus according to the present invention, FIG. 2 is a partially enlarged explanatory diagram of the electrode guide pulley changing device shown in FIG. 1, and FIG. It is a sectional view taken along the line - in the figure.

In FIG. 1, 1 is a workpiece, and 2 is attached to the tip of a stem 3 that is movably provided on a column of the electrical discharge machining apparatus main body (not shown) or on an arm extending from the column onto a machining table. 4 is a motor that raises and lowers the stem 3 in the vertical (Z-axis) direction in the figure and provides machining feed in the Z-axis direction; 5 is a long and thin flexible electrode body such as a tape electrode, a mesh electrode, a wire electrode, etc. (hereinafter simply referred to as "tape electrode"), 6 is a hydraulic ram fixedly provided in the machining head 2 or stem 3, and 7 is a plurality of pulleys 7e, 7f, 7g that automatically operate according to the machining shape, etc. Electrode guide pulley changing device,
8 is a tape electrode supply drum; 9 is a braking roller that rotates the tape electrode supply drum 8 to send out the tape electrode or applies braking force to the tape electrode supply drum 8; 10, 10 are guide rollers; 11, 11; 12 houses the guide rollers 10, 10 and the energizing pins 11, 11, and is driven by the motor 13 to the guide rails 14, 14.
15 is a capstan, 16 is a pinch roller,
17 is the capstan 15 and the pinch roller 1
6, and the guide rail 1 is moved by the motor 18.
An electrode collection position adjustment housing is moved along lines 9 and 19, and 20 is an electrode collection drum for collecting the exhausted tape electrode 5.

In addition, a power supply device that supplies a predetermined voltage pulse for electric discharge machining between the energizing pins 11, 11 and the workpiece 1, a machining tank that accommodates the workpiece 1 and fills the machining fluid inside, and a machining A nozzle for supplying machining liquid to the part, a cross slide table on which the machining tank is placed and its driving motor, in order to provide machining feed in the X-Y axis direction in the figure between the workpiece 1 and the machining head 2, The numerical control device and the like that centrally control the various machining feeds described above according to a predetermined program are the same as those known in the art used in ordinary electrical discharge machining equipment, and are therefore omitted from the drawings.

The tape electrode 5 is pulled out from the electrode supply drum 8, passes between the guide rollers 10, 10 and the current-carrying pins 11, 11, and then passes through the electrode guide pulley (in the state shown in FIG. 1). The electrode collection drum 20 is guided to the tip of the pulley 7e), moves while rotating the pulley, and is subjected to strong tension by the capstan 15 and pinch roller 16, which rotate continuously or intermittently. It is starting to be collected.

During machining, one electrode guide pulley on which the tape electrode 5 is stretched is opposed to the workpiece 1 with a predetermined machining gap maintained, and a power supply device for electrical discharge machining (not shown in the figure) From energizing pins 11, 11
A voltage pulse is applied between the tape electrode 5 and the workpiece 1 through the tape electrode 5, and electrical discharge machining progresses by the discharge erosion that occurs on the surface of the workpiece. In the machining gap,
New machining fluid is sprayed and supplied through a machining fluid jetting nozzle, etc., which is not shown in the figure, so that machining fluid in the machining gap contaminated with machining debris etc. is always replaced with clean machining fluid.

Processing feed between the workpiece and the electrode guide pulley is carried out by moving a cross slide table (not shown in the figure) on which a processing tank containing the workpiece 1 is placed in the X-axis and Y-axis directions, and This is done by moving the entire processing head 2 in the Z-axis direction.

In addition, as the tape electrode wears out as processing progresses, the capstan 15, pinch roller 16, etc. are rotated continuously or intermittently, and the tape electrode worn out due to processing is replaced with a new electrode part one by one. .

The tape electrode 5 may be a simple metal tape or a long and thin metal mesh, but in some cases it may be a metal tape with a large number of cuts etc. so that it becomes a mesh when stretched. It's okay to have something. Also, wire electrodes can be used instead of tape electrodes.

Therefore, in the electric discharge machining apparatus according to the present invention,
As shown in the figure, machining is performed by appropriately exchanging a plurality of electrode guide pulleys 7e to 7g, each having a different radius, depending on the desired shape of the machined part. An embodiment of an electrode guide pulley replacement device for automatically performing this replacement will be described with reference to FIGS. 2 and 3 in addition to FIG. 1.

In the electrode guide pulley changing device 7 shown in the figure, 7a
is the piston rod 6 of the hydraulic ram 6 shown in FIG.
The casing 7b, 7b is attached to the free end of the casing 7a and is moved in the Z-axis direction in FIG. a pair of strut members mounted to extend;
7c is a driven gear rotatably supported near the ends of the pair of support members, 7d, 7d;
have pulleys 7e, 7f, and 7g at their respective tips.
has three arms that are rotatably attached, and is fixed to both sides of the driven gear, respectively; 7h is a timing belt that transmits the rotation of the drive gear 7i to the driven gear 7c;
j is a worm wheel fixed to the drive gear 7i, and 7k is a motor that rotates the worm wheel 7j by means of a worm gear 7l attached to its rotating shaft. In addition, the electrode guide pulley 7
e to 7g are made of materials such as wear-resistant alloys and ceramics.

In the state shown in the figure, the tape electrode 5 is made to run via the tip of the pulley 7e, and is processed into an arc shape corresponding to the outer diameter of the pulley 7e. Subsequently, when attempting to process a circular arc shape with a smaller radius using, for example, the pulley 7f, the worm wheel 7j and the drive gear 7i fixed thereto are moved in the desired direction by rotating the motor 7k. Rotate. In this case, the rotation of the driving gear 7i is transmitted to the driven gear 7c via the timing belt 7h,
Pulley mounting members 7d, 7 fixed to the driven gear
For example, d is rotated 120 degrees counterclockwise,
As the pulley 7e separates from the tape electrode 5,
The pulley 7f comes into contact with the tape electrode and guides it.

Even during the above-mentioned pulley replacement work, the capstan 15 is rotated continuously, and the tape electrode does not loosen, assuming that the pulley 7e separates from the tape electrode and the pulley 7f approaches the tape instead. The work will proceed as follows.

The work of replacing the pulley 7g with a pulley 7g having a smaller radius is also the same as above.

As shown in FIG. 3, the peripheral edge of each pulley 7e, 7f, 7g has a slightly raised rib portion 7.
e', 7e', 7f', and 7f' to prevent the tape electrode 5 from coming off the pulley during processing.

Further, when it is necessary to compensate for a change in the pulley tip position relative to the workpiece 1 due to a difference in the radius of the pulley before and after replacement, the hydraulic ram 6 is operated to move the entire pulley replacement device 7 up and down. The above compensation is achieved by using the motor 4, which feeds the entire machining head 2 in the Z-axis direction, instead of using the hydraulic ram 6.
It is also possible to realize this by driving the .

In addition to replacing the electrode guide pulley,
The electrode delivery position adjustment housing 12 and/or the electrode withdrawal position adjustment housing 17 (see FIG. 1) are moved along the guide rails 14, 14, 19, and 19 by rotating the corresponding motors 13 or 18, respectively. By moving the tape electrode in the left-right direction in the figure and changing the tension angle of the tape electrode with respect to the electrode guide pulley, it becomes possible to correspond to various machining shapes.

Note that the operation of the motor 7k, hydraulic ram 6, pinch roller 15, etc. that should be driven when replacing the electrode guide pulley, or the operation of the motors 4, 13, 18, etc., is dependent on the machining feed between the machining head 2 and the workpiece 1. It is necessary to control them in a related manner, and therefore, their operations are controlled uniformly based on commands from a numerical control device (not shown in the figure) that controls machining feed in the X, Y, and Z axis directions. It is something.

〔Effect of the invention〕

Since the present invention is constructed as described above, it is possible to automatically replace a plurality of electrode guide pulleys each having a different radius, and to machine complex shapes unattended over a long period of time. An electric discharge machining apparatus capable of processing and having high working efficiency is provided.

Note that the configuration of the present invention is not limited to the above-mentioned embodiments. That is, for example, the means for automatically exchanging a plurality of electrode guide pulleys, the configuration of the pulley mounting member 7d, etc. can be changed in various ways as necessary, and in the above embodiment, the Although the wire electrode is configured to be collected using the collection drum 20, it may be configured such that a collection box or the like is provided and the wire electrode is collected in this box, or it is cut and disposed of as appropriate. Accordingly, the present invention encompasses all modifications that can be easily conceived by those skilled in the art within the scope of the invention.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the main parts of an embodiment of the electrical discharge machining apparatus according to the present invention, FIG. 2 is a partially enlarged explanatory diagram of the electrode guide pulley changing device shown in FIG. 1, and FIG.
The figure is a sectional view taken along the line - in FIG. 2. 1... Workpiece, 2... Processing head, 3... Stem, 4... Motor, 5... Tape electrode, 6...
Hydraulic ram, 7... Electrode guide pulley replacement device, 7a
...Casing, 7b, 7b... Support member, 7c
... Driven gear, 7d, 7d ... Pulley mounting member, 7e, 7f, 7g ... Pulley, 7h ... Timing belt, 7i ... Drive gear, 7j ... Worm wheel, 7k ... Motor, 8 ... Tape Electrode supply drum, 9...braking roller, 10,10
... Guide roller, 11, 11 ... Current-carrying pin, 1
2... Electrode delivery position adjustment housing, 13... Motor,
14, 14... Guide rail, 15... Capstan, 16... Pinch roller, 17... Electrode withdrawal position adjustment housing, 18... Motor, 19, 19...
Guide rail, 20...electrode collection drum.

Claims (1)

[Claims] 1. A long and thin electrode body such as a tape electrode, a mesh electrode, a wire electrode, etc. is run along the surface of an electrode guide body facing the workpiece with a predetermined machining gap maintained. In an electrical discharge machining device that performs continuous machining, a plurality of electrode guide pulleys each having a different radius are provided as the electrode guide body, and a necessary one is selected from among the plurality of pulleys according to the machining shape. The electric discharge machining apparatus described above is provided with an electrode guide pulley changing device that selects an electrode guide pulley and makes it face the workpiece. 2. The replacement of the electrode guide pulley is controlled in conjunction with the machining feed by a numerical control device that controls the machining feed of the size, shape, etc. between the electrode guide pulley and the workpiece. The electric discharge machining device described in Section 1.