JPH02237724A - Cutting treatment for wire electrode in wire cut discharge processing - Google Patents

Abstract

PURPOSE:To surely recover wire fragments and eliminate any obstacle against next wire insertion action by selecting the recovery feed direction of wire fragments after cutting based on the stretching condition of a wire electrode before cutting. CONSTITUTION:When it is detected that processing for processed article 2 is finished and the ininterruptedness of a wire electrode 1 in the midway are detected in a detection circuit 24, the electrode 1 is nipped between a tension giving roller 16 and a presser roller 18 by the action of a roller movement mechanism 19, and concurrently energizing pieces 15a and 15b are contacted to the electrode 1. Then tension is given with a roller 16 with a brake 20 fixed, electrification is made between the pieces 15a and 15b from an electrification circuit 22, and wire fragments are recovered in a wire recovery box 9 with heating and fusion made. On the other hand, when abnormal disconnection during discharge processing is detected in the circuit 24, the roller 18 is put in a space with the roller 16, cutting is made similarly, and then the wire fragments which are unable to recover with a travel roller 8 are extracted upward from an upper guide 10a. Thus the wire fragments can surely be recovered.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an automatic wire electrode cutting/feeding mechanism for supplying a wire electrode to a workpiece in wire-cut electric discharge machining, and in particular to a wire electrode cutting and post-cutting treatment. It concerns an improvement in the method.

[Conventional technology]

The wire electrode mouth motion cutting/feeding mechanism of a conventional wire-cut electric discharge machining device is disclosed in, for example, Japanese Patent Application Laid-open No. 107737/1983,
This is disclosed in Japanese Patent Application Laid-Open No. 56-102432 or Japanese Patent Publication No. 126455.

[Problems to be Solved by the Invention] Conventional wire electric discharge machining equipment uses electrical heating and applying tension to straighten the wire electrode and form a narrow diameter portion, and then changes the shape of the tip of the wire by applying current. Since the wire electrodes can be set automatically, the automatic setting of the wire electrodes can be performed more smoothly and reliably than with mechanical cutting.

However, in cases where a wire breakage occurs during processing, fragments (chips) of the broken wire are left behind due to the wire breakage during processing and the energized heating cutting, and after collecting these fragments, a new This requires extensive wire threading work, making it difficult to use this conventional device to its full potential as an automatic machine.

On the other hand, a configuration has been proposed in which the wire is mechanically cut and the remaining wire fragments are collected by a rotating motion, but with this device, the shape of the tip of the wire cutter is deformed, causing it to bend or the surface to become rough. This may cause insertion failure.

In addition, if a wire breaks during processing of a thick plate workpiece, the wire fragments are long and may cause defects such as not being able to collect the wire fragments.Furthermore, if a wire breakage occurs due to an abnormality during processing, the wire breakage may occur. There is a device that pulls out the broken part of the wire electrode from inside the device and automatically inserts it again at the broken part without performing a new cutting operation at a different part.
The tip of the wire electrode that broke due to the abnormality was generally in poor condition, making it difficult to insert it into the small hole of the guide, and there was a possibility that it would be almost impossible to insert it, especially when using a low-clearance guide. .

This problem is also the same for the wire cutting device disclosed in JP-A No. 59-107737, for example, and if the type or wire diameter of the wire electrode changes, it becomes impossible to obtain the tip shape of the wire electrode suitable for automatic return. It was possible.

This invention was made in order to solve the above-mentioned problems, and makes it possible to reliably collect the uncut wire electrode fragments and to obtain a good cut shape when cutting the wire electrode. The object of the present invention is to obtain a method for cutting a wire electrode in wire-cut electrical discharge machining, which can achieve reliable and highly reliable automatic wire electrode cutting and supply.

[Means to solve the problem]

In this invention, when cutting a fixed wire electrode, the state in which the wire electrode is stretched is detected, and wire fragments are collected in an appropriate direction depending on this state.

Furthermore, the present invention allows the conditions such as tension and heating to be applied to the wire electrode to be set when cutting the wire electrode.

Furthermore, the present invention is designed to cut the wire electrode by removing the machining liquid attached to a part of the wire electrode.

[Effect]

In the wire electrode cutting method according to the present invention, when cutting the wire electrode, the cut wire electrode is recovered in an appropriate direction selected based on the state in which the wire electrode was stretched before cutting.

Furthermore, the tension and heating conditions applied to cut the wire electrode are variably set depending on the type and wire diameter of the wire electrode.

Furthermore, the cutting conditions are kept constant by removing the liquid adhering to the wire electrode.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 is a configuration diagram of an embodiment of the wire-cut electrical discharge machining device of the present invention, Figs. 10 and 3 are partial explanatory diagrams of the embodiment of Fig. 1, and Figs. be.

In each figure, (1) is the wire electrode, (la) is the wire fragment, (lb) is the axis along which the wire runs, (2)
is the workpiece, (3) is the machining start hole prepared in advance in the workpiece (2), (4) is the wire bobbin, and (5) (
6) (7) is a wire guide roller that guides the wire electrode (1), (8) is a pair of wire running rollers that run the wire electrode (1) during processing, and (9) is a used wire electrode ( 1) Storage wire collection box, (10a) (
10b) -F lower wire guide, (lla) (llb
) are upper and lower machining nozzles, (12a) and (12b) are upper and lower feeders for supplying machining power to the machining part by being sustained by a machining power source (not shown), (1 3a) (1 3b)
) is the vertical guide, (14) is the wire feed roller,
(15a) and (15b) are the wire feed roller (14) and -
(16) is a conductor for cutting the wire electrode provided between the two-part wire guide (10a) and the conductor (15).
a) A tensioning roller (15b) and the upper wire guide (LOA) is provided at a position away from the axis of the wire path and is used when cutting the wire electrode; (17) is a tensioning roller (16) with rotational driving force; A motor that gives (1
g) The wire electrode (1) is bent between the wire electrode (1) and the tension applying roller (16) when the wire is cut.
(19) is a pressing roller moving mechanism that moves the pressing roller (18) in translation;
(20) is a brake that generates a resistance force against the tensile force by the wire running roller (8) in order to apply appropriate tension to the wire electrode (1) during processing, and (21) is a brake inside the wire collection box (9). A detection plate (22) is provided to detect the presence of the wire electrode (1) and the tension state of the electrode, and (22) is a drive for switching the rotation direction of the motor (17) directly connected to the tension applying roller (l6) between forward and reverse directions. circuit, (24)
is a detection circuit that detects continuity between the upper feeder (12a) and the detection plate (21) in the wire collection box (9). (3a) shown in Figs. 2 and 3 is a lever member, (
4G) (44) is a compression spring, (42) and (43) are air cylinders.

Next, the operation of this embodiment will be explained.

In Fig. 1, during electrical discharge machining, the wire electrode (1) is tensioned and run by the wire running roller (8) while being given appropriate tension by the brake (20). Machining energy is supplied to the wire through the upper and lower feeders (12a) (12b), and the workpiece (2) is
) electrical discharge machining is performed. At this time, as shown in FIG. 2, the presser roller (18) remains retracted toward the left in the figure, and the wire electrode (1) is attached to each roller (18). (16)
The vehicle is traveling from top to bottom along the original axis (1b), with and without contact with the vehicle.

After one shape machining is completed on the workpiece (2), the wire electrode (1) is cut for automatic continuous machining, and the table is moved until the next machining starting hole (3) and axis line (lb) match. After this, the wire is inserted into the starting hole (3) and electrical discharge machining is started again. This operation will be explained with reference to FIGS. 1 to 3.

First, before cutting, check whether the wire electrode (1) is not broken in the middle, that is, the upper guide (13a
), the workpiece (2), the wire passing through the wire traveling rollers (8), and the detection circuit (24) detecting whether or not the wire is continuously stretched from the workpiece (2) to the wire collection box (9). Ue-e Denshi (
12a) and the detection plate (21), it is detected whether there is continuity or not, and a relay or the like is operated accordingly.

Next, the air cylinder (42) drives the presser roller moving mechanism (19) from the state shown in FIG. 2 to the state shown in FIG. and the press roller (l8).

At the same time, the conductors (15a) (15b) are connected to the air cylinder (4
3), it is similarly driven from the right to the left in the figure and comes into contact with the wire electrode (1) as shown in FIG. Holding roller (18
) is connected to the moving mechanism (19) via a lever member (39), and a compression spring (40) applies a force to rotate the wire electrode (1) clockwise in the figure, causing the wire electrode (1) to move against the tension applying roller ( 16), a sufficient frictional force is generated between the wire electrode (1) and the tension applying roller (16).

Next, the brake (20) is fixed, and the tension applying roller (16) is rotated in the direction of arrow A (Fig. 3) by the motor (17).
A tension force is generated in the wire electrode (1) by generating a force that tends to rotate the wire electrode (1). On the other hand, the energizing circuit (22) is the energizing circuit (22).
5a) Supply current to (15b). The wire heat generated by energization is transferred to the energizers (15a) and (15b) and escapes slightly, so the temperature rise of the wire at the middle position between the energizers (15a) and (15b) is the highest, and heating and fusing is performed at this intermediate position. .

After a certain period of time has elapsed since the start of energization, a timer or the like operates, and the energization circuit (22) and drive circuit (23) become open, stopping energization and tension application.

Next, the presser roller moving mechanism (l9) is operated by an air cylinder (
The drive is canceled by the backward movement of the wire electrode (1).
) is released from the sandwiching between the tension applying roller (16) and the pressing roller (step 8). At the same time, the electronics (15a)
) (15b) is similarly released from contact with the wire electrode (1) by the backward movement of the air cylinder (43).

After this cutting is performed, the wire traveling roller (8) is driven to collect the cut wire fragments (1a) downward and stored in the wire collection box (9). This completes the series of cutting operations and collection of wire electrode fragments when the wires are in a connected state before cutting. This operation is shown in FIGS. 4(a) to 4(d). When the cutting and collecting operations are completed, the X and Y tables (not shown) position the wire to the next machining start hole, and then the wire feed roller (14) is driven to move the wire electrode (l) to the next machining start hole. The wire is fed into the hole (3), and by a wire guide mechanism (not shown), the wire is fed to the traveling rollers (8) 2 and the wire collection box (9), thereby completing automatic insertion of the wire.

On the other hand, if the wire electrode (1) is not connected from the upper wire guide (13a) to the wire running roller (8), that is, if the wire is broken due to an abnormality during electrical discharge machining, the wire electrode (1) If the wire is cut in the same manner as described above, the wire fragments remaining between the disconnected part due to an abnormality and the part where the current was cut are transferred to the wire running roller (8).
Since the wire cannot be collected in the wire collection box (9),
It is necessary to perform another action.

Hereinafter, the case of abnormal wire breakage will be explained with reference to the operation explanatory diagram of FIG.

When the electrode wire (1) is abnormally disconnected during electrical discharge machining, the detection circuit (24) detects the feeder (12a) and the detection plate (
Since the wires between 21) are not connected, abnormal disconnection can be detected by detecting that there is no electrical continuity between them. In this case, first, after the wire electrode (1) is sandwiched between the pressing roller (18) and the tension applying roller (16) {Fig. 5(b) l. The wire is heated and cut by applying tension and energizing it in the same manner as described above {FIG. 5(C)}.

Next, the motor (17) that drives the tension applying roller (16)
) by switching the connection of the contacts in the drive circuit (23), reversing the direction of rotation of the tensioning roller (16), and rotating the tensioning roller (16) in the opposite direction for a certain period of time using a timer, etc.
The cut wire fragments (1a) that cannot be recovered by pulling them upward from the upper guide (10a) and recovering them {Figure 5 (
d)}.

Thereafter, the holding roller (I8) and the conductor (15) are returned to their original positions to complete the cutting operation.

After the cutting operation is completed, the machining start hole (3) for that machining is completed.
After positioning at
Move the and back relative to each other and resume machining from there.

In the embodiment of the present invention configured as described above, it is possible to straighten the wire by applying tension and heating with electricity, and by appropriately selecting the current value and tensile force when cutting the wire electrode, cutting can be done. The tip of the latter wire electrode (1) has an appropriate pointed shape, which allows for smooth insertion into the starting hole (3), and also detects the tension of the wire before the cutting operation. The feeding direction is selected to collect the wire fragments after cutting, and even in the event of wire breakage, the wire fragments can be reliably collected and the subsequent insertion operation performed. In particular, it is now possible to reliably collect long wire fragments that occur when the wire breaks during the processing of thick plates, which has been difficult in the past.

In the above embodiment, the upper feeder (12a) and the wire collection box (9) are used to detect the tensioned state of the wire electrode (1).
The circuit (24) detects continuity between the detection plate (21) inside the
However, as shown in Figure 6, the limit switch (
25) may also be used. In other words, the wire electrode (3)
If the tension applying roller (16)/pressing roller (18) to the running roller (8) is connected and tensioned, the limit switch (25) detects this due to the tension of the wire electrode, and the wire After cutting both rollers (16) (1g
) is rotated in the forward direction, and if the wire is broken midway, there is no tension in the wire, so the contact part of the limit switch (25) will protrude to detect the breakage, and after the wire is cut. Both rollers (l6) (Ig) are rotated in opposite directions to collect the wire fragments. In this way, the detection circuit (24) detects wire breakage during processing using a limit switch (25), etc., and only when this is detected, the wire fragments (1a) are collected in the L direction as shown in Figure 5 (d). You may also do so.

Also, in the above explanation, the wire fragments (1a) after being cut are
As shown in Figure (d), since the means for applying tension during cutting is also used as the means for collecting the material upward, the structure of the apparatus is simple.

Next, the broken wire fragments (la) were collected in two directions.
A specific example of storing the storage device and an explanation of its operation are shown in Fig. 7~
It is shown in FIG. In FIG. 7, (50) is a wire fragment storage box provided near the tension applying roller (16), and is positioned at a position to receive wire fragments sent out from the pair of rollers (16) and (18). It is set up. The other configurations are the same as those described above.

In the figure, the used wire electrode (l) during processing and the wire fragments (1a) collected below are placed in the wire collection box (9).
will be stored in. If a wire breakage occurs during processing, the wire electrode (1) will be cut by energization as shown in Figure 3 and then cut as shown in Figure 5 (
The tension applying roller (16) rotates in the opposite direction as shown in d), and this state is shown in FIGS. 8 and 9. Figure 8 shows the wire electrode (1) immediately after being cut by electrical heating, and then, as shown in Figure 9, the tension applying roller (16) is connected to the drive circuit (
23), the motor (17) rotates in the opposite direction, and the roller (16) also rotates in the opposite direction for a certain period of time. As a result, the wire fragments (la) are sent out to the wire fragment storage box (50) and are reliably collected in the storage box (5G).

As in the embodiment shown in FIG.
) into a spiral shape, even long pieces of wire can be collected smoothly. In addition, a storage box (5
0) is provided with an accommodation auxiliary air outlet (51). By guiding the collected wire fragments along with the air current, the collecting operation can be carried out reliably. As in the other embodiment shown in FIG. 11, the suction duct (52) and the suction device (53)
A configuration may also be adopted in which a wire fragment (1a) is accommodated by providing a wire fragment (1a). By providing the storage box as described above, more reliable collection is possible.

In the embodiment described above, a timer is used when the tension applying roller (16) is rotated in the opposite direction for a certain period of time to be collected upward, but instead of this, a circuit is provided to detect the completion of wire fragment collection. Good too. This specific example is shown in Figures 12 to 1.
Shown in Figure 4.

In Fig. 12, (26) is a relay with off-delay function, (27) is a power supply, and tension applying roller (
16) and the upper feeder (12a) through this relay (
26), and the completion of collection of the wire fragments (1a) to the upper part is detected by detecting the loss of this continuity. When the relay (26) detects the completion of collection, the motor (1) is activated for a predetermined short period of time.
7) is continued to be driven to ensure that the wire fragment (1a) is fed into the storage box (50) up to the terminal end.

Figure 13 shows an embodiment in which an optical sensor is used to detect collection of wire fragments (1a). (2g) is an optical sensor disposed directly below the tension applying roller (16) so as to face the wire electrode, and the incident (reflection) of light changes when the wire electrode is present and when it is not present. Accordingly, a detection signal is emitted.

(29) is an AD converter that amplifies the output signal of the optical sensor (28), and the amplifier (30) is an AD converter that converts the analog signal from the amplifier (29) into a digital signal. Input a digital signal to drive the motor (17
) is a control device that controls the operation of the This control device (3
In 1), when the wire fragments are recovered in the reverse direction after the wire electrode is cut by energization and heating, it is determined whether or not the wire electrode fragments are present between the tension applying roller (16) and the upper guide (13a). A signal indicating that the wire electrode is no longer present is received from the optical sensor (28), and completion of collection is identified by the signal indicating that the wire electrode is no longer present. In addition, in order to ensure that the wire fragments are fed into the storage box (50) up to the end, the stop control of the motor (17) is controlled by executing a delay timer function inside the control device (31). It's best to delay it a little.

In the embodiment shown in FIG. 14, the optical sensor is replaced by a magnetic sensor (3
2), which uses magnetism to identify the presence or absence of wire fragments.

By detecting the collection of the wire fragments (1a) as described above, it is possible to prevent insufficient or excessive collection of the wire, even though a timer is also used. Furthermore, even for extremely long wire fragments such as those used in thick plate processing, there is no need to reset the timer to match the length of the wire fragments in order to collect them.

Next, the 15th article describes a further improved structure of the current-carrying means for passing current through the wire electrode and the tension-applying means for applying tension.
It is shown in FIGS.

In Fig. 15, (33) is a wire electrode presser attached to the presser roller drive mechanism (19) and disposed at a position facing the conductor (15a), with one end connected to the roller drive mechanism (19). A fixed U-shaped spring and a wire electrode (15a) provided at the other free end of the spring to conduct electricity.
It has a pressing member that presses against.

The contact pressure of the wire electrode against the conduction current is greater for the lower conduction (15b) due to the presence of the suppression roller (18), and for the upper conduction (15a).
It becomes smaller than that of the wire electrode, and as a result, the wire electrode tends to lift up from the conductor (15a). Therefore, a pusher (33) is provided, and when the roller drive mechanism (19) moves forward, the pusher (33) also advances, thereby pressing the wire electrode against the upper conductor (15a) and ensuring that This allows the wire to be energized.

The embodiment shown in FIG.
b) has a cylindrical shape so as to serve as a two-part guide (13a) for the wire electrode (1). With this configuration, the upper guide (13
Since step a) can be omitted and the structure can be simplified, more reliable energization and disconnection can be achieved.

As shown in FIGS. 17(a), (b), and (e), a tension applying roller (
l6) Preventing the wire from coming off during cutting and collecting wire fragments by providing slits (34) and (35) to prevent the wire from coming off the wire, which have a width sufficiently smaller than the width of the holding roller (l8). I can do it. Instead of the derailment prevention slits (34) and (35), derailment prevention pins (36) and (37) may be provided at the top and bottom as shown in Fig. 18.
Further, as shown in FIG. 19, a configuration may be adopted in which a derailment prevention roller (38) having a wire receiving groove on the outer periphery is provided.

By adopting these structures, wire electrodes can be cut more reliably and wire fragments can be recovered.

In addition, in the above explanation, the electrode wire (1
) has been broken after cutting the wire fragment (1
Although an example of the operation in which recovery in a) is carried out by rotating the tension applying roller (I6) in the opposite direction and sending it upward has been shown, it is natural that the operation is not limited to this. For example, machining start hole (3)
The wire fragment (1a) is extruded sideways from the processing nozzle (l
It is also possible to wash away the chips (1a) with the machining fluid spouted from la).

The structure of another embodiment of the present invention is shown in FIG. 20, and the properties of the cut wire electrode are shown in FIGS. 21-23.

In the figure, (22) is a conductor (15a) (15b)
(23) is a drive circuit that switches and controls the motor (L7) directly connected to the tensioned 5 roller (6) to generate different driving forces; (31) is a drive circuit that supplies different driving currents to the machining and A control device (45) that controls insertion operations and the like is a memory that is provided inside the control device and stores information regarding the type and diameter of the wire electrode.

Machining in the wire cut electric discharge machining device shown in Fig. 20. The cutting operation is substantially similar to that described with respect to FIG. At that time, the memory (
Based on the information stored in the wire electrode type, wire diameter, etc., the control device (31) switches the relay inside the drive circuit (23) and controls the wire electrode so that the optimum cutting tension is applied to the wire electrode. be done. Next, in the same way, the control device (31) switches the relay inside the energizing circuit (22) and supplies the optimum energizing current to the wire electrode (17) to connect the wire electrode (17) between the energizing elements (15a) and (15b). 1) Cut. The purpose of cutting the wire electrode is to ensure smooth insertion, but in order to ensure smooth insertion during insertion,
(I) The tip shape should be moderately pointed, (2)
Cutting is performed to meet the following requirements: (3) no burrs are generated at the tip due to heat generated by electricity; (4) the tip does not change in quality and become extremely soft. There is a need. FIG. 21 shows measurements of the sharp portion and the amount of bending at the tip of wire electrodes (brass wire) having different wire diameters with respect to current flow.

From Fig. 21 (a), in the case of φ0.3 brass wire, it becomes impossible to cut when the current is less than 8 to 9 A, so it is necessary to flow a current of at least IOA or more, but the current is high. If it is too long, the shape of the cut part will not be sharp but will look like it has been torn off, and the amount of bending of the tip will increase rapidly, so the insertion success rate will be extremely low [,
<Decrease. Therefore, in the case of φ0.3 brass wire, it is 10
~18A is the appropriate current range. Similarly, φ0.2 brass wire, φ0. l Even in the case of brass wire, there is an appropriate current range, 5 to 10Δ for φ0.2 brass wire, φ01
Brass wire has a different range of about 3 to 78.

On the other hand, there is an optimal cutting tension value depending on the wire type and wire diameter. FIG. 22 shows measurements of the cutting tension and amount of burr (due to thermal deterioration) during cutting for wire electrodes of different types and wire diameters. From Fig. 22, in the case of brass wire, φ0.1. 0.2 wire diameter, the amount of burr generated during cutting is small regardless of the cutting tension, but in the case of zinc coated wire. The amount of scraping generated during cutting varies greatly depending on the tension applied during cutting, and unless cutting is done in a very short time with a large tension applied, the amount of scraping will increase.
As a result, the insertion success rate is significantly reduced. This tendency also appears in other coated wires, and in the case of zinc-coated wire, by applying a tension of 1200 g or more to a wire diameter of φ0.2, a good cut shape can be obtained with less curling during cutting. In order to apply such a high tension, it is necessary to obtain sufficient frictional tensile force with the tensioning mechanism, but as in this embodiment, the tension applying roller is bent while the wire electrode (1) is bent by the pressing roller (18). (16) Since the contact area is increased, sufficient frictional force can be obtained. As for brass wires, if the wire diameter is φ0.2 or more, it is better to apply a tension of 800g or more to cut the wire, as the wire will not become red hot when energized, and the wire can be cut in a short time, reducing deterioration of the tip. Although a good tip shape can be obtained with less softening due to
If the wire diameter is φ0.1 or less, the original tensile strength is low. The tension must be kept below 500g.

As mentioned above, it is necessary to change the current carrying current and cutting tension value depending on the wire type and wire diameter, but as a result of experiments with various wire electrodes currently in use, we found that the current carrying current is 3 to 2
By switching the cutting tension between 0 A and 100 to 1500 g and optimally combining them, almost all wire electrodes can be cut successfully.

Furthermore, when energizing and disconnecting, the energizing (15a) (15b)
The span also has a large effect on the amount of tip bending and the deterioration of the tip. This is because when the energizing span changes, the energizing length of the wire changes, and the resistance value also changes. 23rd
The figure shows the relationship between the conduction span and the amount of tip bending. As shown in the figure, if the span is too short, the resistance of the wire part will be low, making it impossible to cut. Conversely, if the span is too long, the overall heat generation will increase, but the wire electrode will generate heat in a wide range, leading to melting. It will take more time.

As a result, the range in which the wire tip loses its rigidity also expands, and the amount of tip bending increases significantly.

As a result of experiments with various wires, as can be seen from FIG. 23, the best cutting shape can be obtained when the span between the conductive wires (15a) (tsb) is in the range of 5 to 20 sm.

As mentioned above, the tension value and current value applied to the wire electrode when cutting the wire vary depending on the type and wire diameter of the wire, and the range in which a good tip can be obtained during cutting differs. By allowing these to be freely selected, an optimal shape can be obtained. However, if the type of wire used is constant, then only either the tension value or the current value can be made variable, or as mentioned above, instead of the current value, the wire length between the conductors can be changed to change the wire resistance. It goes without saying that the temperature of the wire may be changed based on the value.

In the embodiment shown in FIG. 21 described above, the optimum cutting conditions can be selected according to the wire type and wire diameter.
It is possible to always obtain the optimum shape of the cut portion, and as a result, it is possible to significantly improve the reliability of wire electrode insertion.

FIG. 24 shows the structure of another embodiment for changing the applied current and tensile force during cutting as in the embodiment of FIG. 20.

In the figure, (46) and (47) are D/A converters, (43
)(49) is a transistor. Fig. 20 shows an example in which the switching between the energizing circuit (22) and the drive circuit (23) is performed using a relay, but as shown in Fig. 24, current variable elements (48) (49) such as transistors and D/A conversion are used. vessel(
46) and (47), and by controlling the transistors (48) and (49) and changing the current according to commands from the control element (31), it is possible to perform more fine-grained switching.

Also, various configurations such as using a rotary switch instead of a relay etc. can be adopted.

Another embodiment of the present invention capable of detecting the completion of cutting of the wire electrode is shown in FIG. In the figure, (15
a) (15b) is electronic, (22) is electronic (15a)
) (15b) is an energizing circuit that supplies 74 current. (3
1) is a control device that controls processing, insertion, cutting, etc. (56) is a disconnection detection circuit provided in parallel with the energizing circuit (22). (54) is a photocabra, (55) beam 1/-.

Machining in the wire cassette 1/electrical discharge machining device shown in Fig. 25,
The cutting operation is substantially similar to that described with respect to FIG. At that time, the wire electrode (1) is connected to the tension applying roller (16).
) and the current applied by the wire electrode (15), the current-carrying circuit (22) is in a short-circuited state through the wire electrode (1), so the disconnection detection circuit (56) The human voltage to the wire is almost zero (only the voltage drop due to wire resistance). Electronics (15a) (15b
), the current-carrying circuit (22) enters the oven state, so the input voltage to the disconnection detection circuit (56) rises to the power supply voltage of the current-carrying circuit (22), and the photocoupler (54) ]7, the relay (55) is turned on,
A disconnection detection signal is sent to the control device (31). The detection delay at the time of disconnection is extremely small, on the order of several tens of microseconds. The control device (31) turns off the drive for applying tension to the energizing circuit (22) and the motor (17) in response to the disconnection detection signal from the disconnection detection circuit (56), thereby energizing the wire electrode (1). and tensioning is stopped.

The configuration of another embodiment capable of detecting completion of cutting as in the embodiment of FIG. 25 is described in Section 26. No. 26 shown in Figure 27
In the embodiment shown in the figure, disconnection is detected based on the presence or absence of voltage across a resistor inserted in series in the energizing circuit (22), and it is detected that the energization is no longer present due to disconnection, and a disconnection completion signal is sent to the control device. (31) In the embodiment shown in FIG. 27, an optical sensor (28) is provided between the conductors (15a) and (15b), and the cutting completion detection is performed through the amplifier (29) and A/D converter (30). Send a signal to the control device (3l).

By adopting the configurations shown in FIGS. 25 to 27, a disconnection detection circuit (56), a sensor (28), etc. that detect disconnection of the wire electrode (1) at the intermediate portion of the conductor (15a) (151)), etc. By providing a cutting detection means, it is possible to instantly detect the cutting of the wire electrode, and even if the cutting time changes due to different diameters of the wire, or if water etc. adheres to the wire and a longer cutting time is required, etc. However, since disconnection can be reliably detected, it is possible to prevent the energization time from becoming longer than necessary, or conversely from insufficient energization. Incidentally, if the disconnection detection means does not detect disconnection after a predetermined period of time has elapsed, the operation is stopped (11-) and a g warning is issued, thereby eliminating the problem of the disconnection being left unattended. The tip of the wire electrode is guided after cutting, allowing reliable automatic insertion.

The configuration of another embodiment of the present invention is shown in FIG. 28, and its detailed explanation is shown in FIG. 29. Shown in Figure 30.

In the figure, (57) and (58) are guide vibrator lifting air inlets. (59) is an air pipe for supplying air when driving the guide pipe (64) in the downward direction;
) is an air pipe for supplying air when driving the guide pipe (64) in the upward direction, (61) is an O-ring, (
62) is the air outlet, (63) is the air outlet, (65)
) is an elevating guide mechanism that accommodates the guide pipe (64) and also functions as a cylinder, (66) is a feed-out guide provided under the wire insertion feed roller (14), and (67) is a feed-out guide (66). The vibrator is fixed to , and (6g) is the cylinder lid.

The machining and cutting operations in the wire-cut electric discharge machining apparatus shown in FIG. 28 are substantially the same as those described in connection with FIG. Here, the operation of the mechanism for guiding the wire electrode provided between the wire insertion and feeding roller (14) and the two-part guide (13a) will be explained with reference to FIGS. 29 and 30. A feeding guide (66), cylinder (65), guide vibrator (64), etc. for guiding the wire are connected to the wire insertion feeding roller (14) and the energizing means (ISa) (15
b).

During electrical discharge machining 2 The wire electrode is on its running axis (lb)
As shown in Figure 29, the pressure roller (18
) and the conductor (15) are respectively stored at predetermined positions offset from the vicinity of the axis (1b). The guide vibrator (64) is lowered along this axis, and the wire runs through it.

When air is supplied into the cylinder (65) through the air piping (60) and guide vibe lifting air inlet (58) from the state shown in FIG. 29, the cylinder is closed by the lid (68), so the guide pipe Lift up (64). As a result, as shown in FIG. 30, the wire electrode (1) in the portion of the energizing means for cutting the wire is exposed, and the cutting operation as described above becomes possible. When the guide pipe (64) rises, the air in the cylinder (65) passes through the gap between the vibrator (67) and the guide pipe (64) and becomes air blown out from the tip of the guide pipe (63). Also air piping (60)
The air from the air also passes through the air jet port (62) and becomes jet air (63). This jetted air can remove water droplets adhering to the cutting wire, thereby making it possible to maintain constant cutting conditions.

When the cutting operation and other operations are completed, air is supplied into the cylinder (65) through the air pipe (59) and the air inlet (57) to lower the guide pipe (64) to the state shown in Fig. 29. Return. At this time, the air in the cylinder (65) escapes from between the guide pipe (64) and the lid (68).

As described above, by lowering the guide pipe (64) which can be raised and lowered to a position close to the -hi section guide (13a), it becomes possible to reliably guide the wire when sending out the wire electrode.

In addition, in the above example, it is also possible to correct the bending of the wire electrode (1) at the cutting part by repeating raising and lowering the guide pipe (64) several times before cutting.

〔Effect of the invention〕

As described above, according to the present invention, the direction in which the wire fragments are collected and sent after cutting is selected based on the tension state of the wire electrode before the wire electrode is cut, so that the wire fragments can be collected reliably. This will prevent any hindrance from occurring in the next wire insertion operation. Furthermore, since the tension and heating conditions for cutting the wire electrode by electrical heating can be set, it is possible to obtain a good cut shape suitable for automatic wire insertion. Furthermore, since the liquid adhering to the wire electrode is removed and the cutting conditions are kept constant, a reliable and highly reliable cutting process can be achieved.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a wire-cut electrical discharge machining apparatus according to an embodiment of the present invention, Figs. 2 and 3 are enlarged views of main parts of the embodiment of Fig. 1, and Figs. Operation explanatory diagram, 6th.
FIG. 7 is a block diagram showing another embodiment of the present invention, FIGS. 8 and 9 are explanatory diagrams of the operation of the embodiment of FIG. 7, FIGS. 21 to 23 are graphs for explaining the properties of the cut portion of the cut wire electrode, and FIGS. 24 to 28 are diagrams illustrating the configuration of a device according to still another embodiment of the present invention. Block diagram of an apparatus according to another embodiment No. 29. FIG. 30 is a partially enlarged explanatory diagram of the embodiment of FIG. 28. (1) is a wire electrode, (8) is a wire running roller, (1)
5) is a conductor, (16) is a tension applying roller, (18)
is the presser roller, (20) is the brake, and (22) is the energizing circuit. (23) indicates a drive circuit. In addition, the same reference numerals in the figures indicate the same or equivalent parts. Figure 2

Claims (5)

[Claims] (1) In wire-cut electric discharge machining, in which a workpiece is machined by generating electrical discharge between a wire electrode and a workpiece, (a) a step of statically fixing a part of the wire electrode; and (b) the above-mentioned statically fixing. (c) Detecting the tension state of the wire electrode before the static fixation and determining whether the wire electrode was properly tensioned or if the wire electrode was broken. (d) When it is determined that the wire electrode has been properly stretched, the cut piece on the advanced side is moved in the same direction as the wire electrode feeding direction during machining, and the wire electrode is stretched properly. or, if it is determined that the wire electrode is broken, the cut piece on the advanced side is removed from the workpiece by traveling in the opposite direction to the wire electrode feeding direction during processing. A method for cutting wire electrodes in electrical discharge machining. (2) In wire-cut electrical discharge machining, in which the workpiece is machined by generating electrical discharge between the wire electrode and the workpiece, (a) a step of statically fixing a part of the wire electrode; and (b) the above-mentioned statically fixing. (c) supplying power to a part of the fixed wire electrode, energizing it, and setting appropriate energizing conditions according to the wire electrode when energizing; (d) cutting the wire electrode based on the above-mentioned tension application and energization; (e) removing the advanced side fragment of the cut wire electrode from the workpiece. , A method for cutting a wire electrode in wire-cut electric discharge machining. (3) In wire-cut electric discharge machining, in which the workpiece is machined by generating electrical discharge between the wire electrode and the workpiece, (a) a step of statically fixing a part of the wire electrode; and (b) the above-mentioned statically fixing. (c) Applying tension to the part of the fixed wire electrode, and when applying the tension, apply an appropriate tension according to the wire electrode. (d) cutting the wire electrode based on the above-mentioned energization and tension application; (e) removing the advanced side fragment of the cut wire electrode from the workpiece. , A method for cutting a wire electrode in wire-cut electric discharge machining. (4) In wire-cut electric discharge machining in which a workpiece is machined by generating electrical discharge between a wire electrode and a workpiece, (a) a step of statically fixing a part of the wire electrode; and (b) the above-mentioned statically fixing. (c) supplying electric power to the part of the wire electrode to which the tension is applied and energizing it; (d) applying the tension; (e) detecting the tensioned state of the wire electrode before the above-mentioned stationary fixation to determine whether the wire electrode was properly tensioned or whether the wire electrode was broken; (f) When it is determined that the wire electrode has been properly stretched, the advanced side fragment of the cut wire electrode is run in the same direction as the wire electrode feeding direction during processing. When the wire electrode is removed from the workpiece or it is determined that the wire electrode has been broken, the advanced side fragment of the cut wire electrode is removed from the workpiece by traveling in the opposite direction to the wire electrode feeding direction during processing. A method for cutting a wire electrode in wire cut electrical discharge machining, comprising the steps of: (5) In wire-cut electrical discharge machining, which involves interposing machining fluid between the wire electrode and the workpiece to generate electrical discharge to machine the workpiece, (a) a step of fixing a part of the wire electrode stationary; (b) a step of removing machining fluid attached to a part of the wire electrode fixed stationary; (c) a step of supplying power to a part of the wire electrode fixed stationary; (d) ) A method for cutting a wire electrode in wire-cut electric discharge machining, comprising the steps of: (e) removing a fragment on the advanced side of the cut wire electrode from a workpiece.