JP2599392B2 - NC electric discharge machine with separate control - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an NC electric discharge machine, and more particularly to an NC electric discharge machine having two main shafts, each of which is independently controlled to move.
It relates to an electric discharge machine.

[Conventional technology]

In general, in EDM, a single shaped electrode has been used, or a plurality of electrodes have been appropriately replaced to perform workpiece machining one by one. Such a processing method is inefficient, and for mass production, a method of providing a plurality of spindle heads and simultaneously processing a plurality of workpieces is employed. For example, JP 62
Japanese Patent Application Laid-Open No. 15015 discloses that a plurality of workpieces are simultaneously processed by the same number of electrodes attached to a spindle head capable of performing servo feed independently of each other. The gist of the present invention is that, when a plurality of workpieces are simultaneously machined by controlling the discharge state of each spindle head, machining delays caused in individual workpieces and machining under specific conditions are arbitrarily changed as necessary. Thus, each spindle head can maintain an optimal discharge state. Japanese Patent Application Laid-Open No. 55-96229 discloses a wire cut electric discharge machine in which four independent machining heads are provided two on each of two opposite long sides of the machine. ing. The gist of the present invention is to improve the processing accuracy by increasing the processing speed by about four times, eliminating the necessity of changing the work during the processing, and shortening the arm length of each processing head.

[Problems to be solved by the invention]

However, when processing a single large workpiece, using a large shaped electrode increases the time and cost of electrode fabrication,
In addition, because of the heavy weight, an electric discharge machine having a highly rigid spindle head and a feed driving mechanism for the spindle head is particularly required. At the start of machining, only a part of the shaped electrode closest to the workpiece is subjected to electric discharge machining, and the process is gradually expanded to the machining of the entire shaped electrode. In addition, when a large workpiece is machined stepwise by appropriately replacing a plurality of partial electrodes, there is a problem that the machining time becomes longer. In the case of a type in which multiple spindle heads are simply set up side by side,
Since the entire strokes of the adjacent guides do not overlap, for example, both electrodes cannot move to one end of the table, and there is a blind spot area where machining cannot be performed on each of the two spindle heads. .

Therefore, an object of the present invention is to provide a large-scale electric discharge machine having a spindle head having a high rigidity and a feed driving mechanism thereof, which eliminates the need for a large-sized electrode which is extremely difficult to manufacture when machining a large workpiece. It is not necessary to do so. And, using two small electrodes that are relatively small and easy to manufacture and can be mounted on the standard spindle head, separate parts of the work are processed simultaneously or separately, and thus the processing until the work is completed It is to save time. Another object is to make the two electrodes movable to the entire processing area to eliminate the blind spot in the processing area of each electrode.

[Means for solving the problem]

In view of the above object, the present invention provides an NC electric discharge machine controlled by two heads, in which X, Y, and Z-axis feeds are respectively applied to two embossing electrodes to perform electric discharge machining of a workpiece. A work table fixed to the work table, a processing tank provided on the base so as to surround the work table and receiving a working fluid, and three axes of X, Y, and Z axes on the work table Electrode moving means for moving each of the two engraving electrodes over a processing region in a direction, the X-axis guide extending to a rear portion of the processing tank provided on the base. 1 and 2 saddles that move left and right along, 1 and 2 saddle feed drive mechanisms that move the 1 and 2 saddles separately, and along a Y-axis guide provided on each of the 1 and 2 saddles One and two spindle heads that move back and forth; And first and second spindle head feed drive mechanism for moving separately spindle head holds each different two sinker machining electrode and a lower end, it said provided first and second respective spindle head Z
An electrode moving means comprising: one and two main shafts moving up and down along a shaft guide; one and two main shaft feed driving mechanisms for moving the one and two main shafts separately; and the one and two saddles A feed command is sent to the feed drive mechanism, the one and two spindle head feed drive mechanisms, and the one and two spindle feed drive mechanisms, and the three X, Y, and Z axes of the two engraving electrodes are sent out. Provided is a two-head control NC electric discharge machine comprising: an electric discharge machining control device that independently controls movement in the axial direction.

(Operation)

Electrodes are attached to the ends of the two spindles, respectively, and two electrodes move in three axes of X, Y, and Z, respectively, for one large work placed on one table, and are paralleled simultaneously. That is, electrical discharge machining is advanced.

〔Example〕

Hereinafter, the present invention will be described in more detail based on embodiments shown in the accompanying drawings. FIG. 1 is a perspective view of a two-head control NC electric discharge machine according to the present invention, and FIG. 2 is a top view of the electric discharge machine of FIG.

A table 12 on which a workpiece W is placed
Is fixed, and a processing tank 28 for receiving a processing liquid is provided around the fixing tank. A processing liquid tank 36 also serving as a step is provided on the front side of the base 10, and stairs 38a and 38b are provided on the left and right sides thereof. The working fluid tank 36 has a built-in filter and has a purifying function. The processing liquid tank 36 and the processing tank 28 are connected by a pipe 18 via a pump P. When the work W is fixed on or removed from the table 12, the processing liquid is supplied from the processing tank 28 to the processing liquid. When the workpiece W is moved to the tank 36 and the workpiece W is processed, the purified processing liquid is sent from the processing liquid tank 36 to the processing tank 28. Further, a front wall 30 of the processing tank 28 can be opened and closed by a link 32. When loading and unloading the work W, the worker climbs on the upper surface of the processing liquid tank 36 also serving as a step and uses the handle 34 provided on the front wall 30 of the processing tank 28 to lower the front wall 30 downward. Grate and open. After the work W is fixed on the table 12, the front side wall 30 is closed. In this closed state, it is possible to seal with a suitable packing member so that the working liquid does not leak.

On the rear upper surface of the base 10, 2
Two parallel left-right guides 14 extend in the X direction. On this left-right guide 14, two saddles 16a and 16b
Are mounted so as to be movable left and right. The feed mechanisms for moving the saddles 16a and 16b in the left-right direction are a ball screw shaft and a ball nut mechanism, respectively.
42a and 42b are rotatably extended to the vicinity of the center of the table 12. Ball nuts (43a, 43b) fixed to the bottom surfaces of the left end of the saddle 16a and the right end of the saddle 16b are screwed with the ball screw shafts 42a, 42b. Therefore, the movement range of the saddle 16a is from the left end of the X axis to contact with the saddle 16b located at the right end of the X axis, and the movement range of the saddle 16b is from the right end of the X axis to contact the saddle 16a located at the left end of the X axis. It is. MXa and MXb respectively rotate the ball screw shafts 42a and 42b,
This is a servomotor that drives the saddles 16a and 16b in the X direction.

Over the left end of the left-right guide 14 and the left end of the saddle 16a, over the right end of the left-right guide 14 and the right end of the saddle 16b, and further over the right end of the saddle 16a and the left end of the saddle 16b. The bellows type covers 40a, 40b, 40c are attached respectively. This protects the left-right guide 14, the ball screw shafts 42a and 42b, and the like.

Beams 19a and 19b extending above the table 12 are fixed on the saddles 16a and 16b, respectively. Beam 1
A front-rear direction guide (not shown) is provided on each of 9a and 19b.
20a and 20b are configured to be movable in the front-rear direction (Y direction). When the spindle heads 20a and 20b are moved in the Y direction, the same boom screw shaft and ball nut mechanism (not shown) is used as in the case of the above-mentioned left and right movements.
Covered by 44a, 44b. MYa and MYb are servomotors that rotate these ball screw shafts to drive the spindle heads 20a and 20b in the Y direction.

The left and right spindle heads 20a, 20b protrude inward from the left and right beams 19a, 19b, respectively. Therefore, in the present embodiment, when the ball nuts 43a, 43b in the X direction move to the center ends of the ball screw shafts 42a, 42b as described above, the respective spindles 21a, 21b provided on the respective spindle heads 20a, 20b are moved. Can move to the outside of the processing tank 28. The spindles 21a and 21b are movable in the vertical direction (Z direction) along a vertical guide (not shown) provided on the spindle heads 20a and 20b, and are covered by bellows-type covers 22a and 22b. Electrodes 24a, 24b (24a are not shown) are attached to the tips of the main shafts 21a, 21b, respectively. In this embodiment, the workpiece W is used as the electrode 24b.
Is used. A ball screw shaft / ball nut mechanism for vertically moving the spindles 21a, 21b is provided in the spindle heads 20a, 20b, and is driven in the Z direction by servo motors MZa, MZb, respectively. The normal processing area refers to a range in which the electrode can move inside the processing tank. In this embodiment, both spindle heads 20a, 20
Both electrodes 24a and 24b mounted on b can move over the entire range of the processing area. For example, when the right spindle head 20b moves to the vicinity of the left side of the processing tank, the left spindle head 20a
Has an X-axis stroke that can be retracted outside the left side of the processing tank 28.

The discharge state of the servomotors MXa, MYa, MZa and the electrode 24a is controlled by the electric discharge machining control device 26a, while the discharge state of the servomotors MXb, MYb, MZb and the electrode 24b is controlled by the electric discharge machining control device 26b. . The electric discharge machining control devices 26a and 26b have a machining power supply, a gap control, and NC circuits. Of course, the electric discharge machining control devices 26a and 26b may be composed of one device, and may have a function of controlling the discharge state of all the servomotors and the two electrodes.

Since the movements of the two spindle heads are operated by the NC program, the two spindle heads do not usually collide, but there is a possibility of collision due to an NC program error or the like. In order to prevent this, in the present embodiment, the limit switch 5 is provided at the right end of the saddle 16a.
A dog 52 is attached to a position corresponding to 0 and a left end of the saddle 16b to detect contact. And limit switch 50
From the EDM control devices 26a and 26b
The movement of the left and right spindles 21a, 21b in the X, Y, Z directions is stopped and an alarm is issued, or the both spindles 21a, 21b
Is controlled to determine whether one of the main spindles is moved in the release direction. Since the left and right spindle heads have the collision preventing means as described above, it is safe even when an abnormality such as a program error or an operation error occurs.

If the electric discharge machine having such a mechanical configuration is energized and controlled, electric discharge machining can be performed on two portions of the workpiece W simultaneously and in parallel using two electrodes.

〔The invention's effect〕

As is clear from the above description, according to the present invention, when machining one large workpiece, electric discharge machining can be performed simultaneously and in parallel using two electrodes. In other words, it is sufficient to prepare a relatively small and simple partial electrode without preparing a single large-sized electrode, which saves the labor and cost of manufacturing the electrode, and has a specially high-rigidity spindle mechanism. There is no need to use an electric discharge machine. Since two partial electrodes are used and processed in parallel, the processing speed is improved, and
There is no inefficiency that the electric discharge machining is performed only on the part closest to the work at the start of machining by the individual shaped electrodes. Furthermore, since the X-axis guide is shared and both electrodes can be moved to the entire processing area, there is no processing area with a blind spot. For example, when the four corners of a large workpiece are machined with the same electrode, there is no inconvenience such as preparing two electrodes or replacing the electrode with the other spindle.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a two-head control NC electric discharge machine according to the present invention, and FIG. 2 is a top view of the electric discharge machine of FIG. 10 ... Base, 12 ... Table, 14 ... Left and right guide, 16a ... Left saddle, 16b ... Right saddle, 19a ... Left beam, 19b ... Right beam, 20a ... Left spindle head , 20b… right spindle head, 24b… right electrode, 26a… left EDM control device, 26b… right EDM control device, 28… machining tank, 36… working fluid tank also serving as step platform, 42a ... Ball screw shaft for left saddle, 42b ... Ball screw shaft for right saddle, 50 ... Limit switch, 52 ... Dog, MXa, MXb, MYa, MYb, MZa, MZb ... Servo motor.

Claims (3)

(57) [Claims] 1. X, Y, and two electrodes for engraving, respectively.
In an NC electric discharge machine controlled by two heads, which feeds in the Z-axis direction and discharges a workpiece, one work table fixed on the base, and the work table is surrounded by the work table. A working tank for receiving a working fluid; and an electrode moving means for moving the two engraving working electrodes respectively over a working area in three X, Y, and Z axes on the work table. Wherein the first and second saddles which move left and right along an X-axis guide extending to the rear of the processing tank provided on the base, and the first and second saddles are separately moved. One and two saddle feed drive mechanisms; one and two spindle heads that move back and forth along a Y-axis guide provided on each of the one and two saddles; and separately move the one and two spindle heads. One and two spindle head feed drive mechanisms and One and two spindles that respectively hold two different engraving electrodes and move up and down along a Z-axis guide provided on each of the one and two spindle heads; and the one and two spindles. An electrode moving means composed of one and two spindle feed driving mechanisms for separately moving the main spindle, the one and two saddle feed driving mechanisms, the one and two spindle head feed driving mechanisms, and the one and two main spindles By sending a feed command to a feed drive mechanism, X,
An NC electric discharge machine controlled by two heads, comprising: an electric discharge machining control device for independently controlling movement in three directions of Y and Z axes. 2. The electrode moving means further comprises one and two beams respectively fixed to the one and two saddles so as to project on the work table, and wherein the one and two main axes are the one and two. 2. The two-head control NC electric discharge machine according to claim 1, wherein the NC electric discharge machine moves back and forth in a posture facing inward along the Y-axis guide provided on each of the two beams. 3. The one and two saddles are provided on at least one of the saddles with X,
A patent is provided in which contact detection means for preventing collision of the first and second saddles is provided when the Y and Z axes move in three axis directions, and a contact signal from the contact detection means is issued to the electric discharge machining control device. The NC electric discharge machine controlled by two heads according to claim 1 or 2.