WO2015125259A1

WO2015125259A1 - Wire electric discharge machining apparatus

Info

Publication number: WO2015125259A1
Application number: PCT/JP2014/054094
Authority: WO
Inventors: 大友　陽一; 尚志柿花
Original assignee: 三菱電機株式会社
Priority date: 2014-02-20
Filing date: 2014-02-20
Publication date: 2015-08-27
Also published as: CN106029275B; DE112014006130B4; CN106029275A; DE112014006130T5; JP5622981B1; JPWO2015125259A1

Abstract

In order to obtain a wire electric discharge machining apparatus which can prevent a wire collection roller of a wire electrode collection part from being wetted and an extra fine wire electrode from being sucked into a suction part at the time of connection of the extra fine wire electrode, in the present invention, a wire electric discharge machining apparatus is configured to be provided with: a liquid pump which supplies, to an aspirator, a machining fluid at a collection flow rate enough to convey the wire electrode in a lower guide pipe; a suction device which sucks the machining fluid corresponding to the collection flow rate from a pipe end; and an NC device comprising a determination unit which determines that the leading end of the wire electrode has arrived in front of the pipe end at the time of connection work of the wire electrode, and a control unit which on the basis of the determination by the determination unit, decreases the discharge flow rate of the liquid pump and the suction flow rate of the suction device from a collection flow rate and a suction flow rate that are enough to convey the wire electrode in the lower guide pipe to a collection flow rate and a suction flow rate at which the wire electrode is not sucked into the suction part of the pipe end.

Description

Wire electrical discharge machine

The present invention relates to a wire electric discharge machining apparatus, and more particularly to wire electrode connection.

Generally, in a wire electric discharge machining apparatus, a wire electrode having a diameter of φ = 0.3 mm to 0.1 mm is used, and the tip of the wire electrode cut after the previous electric discharge machining by the wire electrode automatic connection mechanism is an upper wire electrode. It is automatically sent to the wire electrode recovery section through the guide section, workpiece starting hole, lower wire electrode guide section, and lower wire electrode feed section, and the wire electrode is connected for the next electric discharge machining. Is called.

Conventionally, a wire electrode guide part that guides a wire electrode that has passed through a lower nozzle in a horizontal direction along a guide roller with a pressure fluid, a first fluid ejection part that removes a machining tip attached to the wire electrode, and a first fluid A second fluid ejection portion that applies thrust to the wire electrode that has passed through the ejection portion, a guide pipe that guides the jet and wire electrode from the second fluid ejection portion, and a jet and wire electrode that has passed through the guide pipe A wire electrode transport device using a pressure fluid of a wire electric discharge machining apparatus that includes a fluid recovery unit that separates a jet from the fluid discharge device is disclosed (for example, see Patent Document 1).

Japanese Patent Laid-Open No. 5-92322

When the wire electrode has a diameter of φ = 0.05 mm or less and cannot be straightened by annealing, an extremely thin wire electrode having a low waist is used. In the conventional wire electric discharge machining apparatus described in Patent Document 1, In order to increase the conveying force of the fine wire electrode, it is necessary to increase the ejection flow rate of the second fluid ejection part (for example, 6 l / min or more). However, if the ejection flow rate is increased, the wire recovery of the wire electrode recovery part There is a problem that the roller (wire winding device) gets wet and the wire electrode becomes entangled with the wire recovery roller and cannot be connected. In order to solve this problem, the fluid recovery part is provided with a mechanism for sucking and collecting the carrier liquid. However, if the suction force of the suction part is increased, an extremely fine wire electrode is sucked into the suction part, and the connection is caused. There is a problem that it is not possible.

The present invention has been made in view of the above, and does not wet the wire collection roller of the wire electrode collection unit when connecting an ultrafine wire electrode, and the ultrafine wire electrode is sucked into the suction unit. It aims at obtaining the wire electric discharge machining apparatus which is not rare.

In order to solve the above-described problems and achieve the object, the present invention provides a lower die for positioning a wire electrode during electric discharge machining, a lower die disposed below the lower die, and in contact with the wire electrode. A lower wire electrode guide section having a lower power supply for supplying current, a wire recovery roller for holding and pulling the wire electrode, and a pipe end for separating the wire electrode and the processing liquid; and a wire electrode recovery section having An aspirator that is disposed between the lower wire electrode guide part and the wire electrode recovery part and ejects a processing liquid that sends the wire electrode to the wire electrode recovery part, and a lower guide pipe that guides the wire electrode to the wire electrode recovery part And a lower wire electrode feed section having a recovery flow rate sufficient to transport the wire electrode in the lower guide pipe to the aspirator. A liquid pump for feeding, a suction device for sucking a working fluid corresponding to the recovered flow rate from the pipe end, and a determination unit for determining that the tip of the wire electrode has reached before the pipe end during wire electrode connection work Based on the determination of the determination unit, the discharge flow rate of the liquid pump and the suction flow rate of the suction device are changed from the recovery flow rate and the suction flow rate sufficient to transport the wire electrode in the lower guide pipe. And an NC device having a recovery flow rate that is not sucked into the suction portion of the pipe end and a control unit that lowers the suction flow rate.

The wire electrical discharge machining apparatus according to the present invention does not wet the wire recovery roller of the wire electrode recovery unit and connects the ultrafine wire electrode, and the ultrafine wire electrode may be sucked into the suction unit. No effect.

FIG. 1 is a schematic diagram showing a wire electrode traveling system of an embodiment of a wire electric discharge machining apparatus according to the present invention. FIG. 2 is a longitudinal sectional view of the upper wire electrode guide portion of the embodiment. FIG. 3 is an enlarged vertical cross-sectional view of the upper wire electrode guide portion of the embodiment in a phase different from that of FIG. FIG. 4 is a cross-sectional view showing the lower wire electrode guide portion and the lower wire electrode feed portion of the embodiment. FIG. 5 is a cross-sectional view showing a lower wire electrode guide portion and a lower wire electrode feed portion according to the embodiment, which is 90 ° out of phase with FIG. 4. FIG. 6 is a side view showing a pipe end of the wire electrode recovery portion of the embodiment. FIG. 7 is a cross-sectional view taken along line BB in FIG. FIG. 8 is a wire electrode feed time chart of the wire electrode recovery part of the embodiment.

Hereinafter, embodiments of a wire electric discharge machining apparatus according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment FIG. 1 is a schematic view showing a wire electrode traveling system of an embodiment of a wire electric discharge machining apparatus according to the present invention, and FIG. 2 is a longitudinal sectional view of an upper wire electrode guide portion of the embodiment. FIG. 3 is an enlarged vertical sectional view of the upper wire electrode guide portion of the embodiment different from that of FIG. 2, and FIG. 4 shows the lower wire electrode guide portion and the lower wire electrode feed portion of the embodiment. FIG. 5 is a cross-sectional view showing a lower wire electrode guide portion and a lower wire electrode feed portion of the embodiment, and is a cross-sectional view different from that in FIG. 4 by 90 °, and FIG. 6 is a wire electrode recovery portion of the embodiment. 7 is a side view showing the pipe end of the section, a cross-sectional view taken along line BB of FIGS. 7 and 6, and FIG. 8 is a wire electrode feed time chart of the wire electrode recovery section of the embodiment.

As shown in FIG. 1, the wire electric discharge machining apparatus 100 of the embodiment includes a wire electrode holding unit 10, an upper wire electrode feeding unit 30, an upper wire electrode guide unit 40, a lower wire electrode guide unit 60, and a lower part. A wire electrode feeding unit 70, a wire electrode collecting unit 80, and an NC device 90 are provided.

The wire electrode holding unit 10 includes a bobbin 11 around which the wire electrode 1 is wound, and

pulleys

12a, 12b, and 12c that change the feeding direction of the wire electrode 1.

The upper wire electrode feeding section 30 guides the wire electrode 1 to the lower upper wire electrode guide section 40, the feed roller 21 that feeds the wire electrode 1,

pinch rollers

22 a and 22 b that wind the wire electrode 1 around the feed roller 21, and the wire electrode 1. An upper guide pipe 31 and a guide pipe head 32 for sending air downward into the upper guide pipe 31 are provided.

As shown in FIG. 1 and FIG. 2, the upper wire electrode guide part 40 is in contact with the wire electrode 1 and supplies an electric current to the wire electrode 1, and an upper side disposed above the upper supply electron 42. The upper guide 44, which is composed of a guide 44a and a lower guide 44b arranged on the lower side, guides the wire electrode 1 so as to contact the upper power supply 42, and is arranged on the upper side of the upper guide 44a, and the lower end of the upper guide pipe 31. The wire track 49 into which the portion is inserted and the lower guide 44b are disposed below, and the wire electrode 1 is sent downward and the tip thereof is sent to the lower wire electrode guide portion 60 through the processing start hole of the workpiece 51. A jet nozzle 45 that ejects liquid, and an upper machining liquid nozzle 46 that is disposed below the jet nozzle 45 and sprays the machining liquid onto the workpiece 51 during electric discharge machining. Disposed spout of the upper machining liquid nozzle 46, an upper die 43 for positioning the wire electrode 1 during the discharge machining, and a upper guide block 41 for holding them, the.

Although not shown, a cutter or a cutting unit for cutting the wire electrode 1 with Joule heat due to electric current is disposed above the upper wire electrode guide portion 40. The cutting unit is movable in the lateral direction. When cutting the wire electrode 1, the upper guide pipe 31 is raised to create a gap between the lower end of the upper guide pipe 31 and the wire track 49, and the cutting unit is moved into the gap to cut the wire electrode 1. To do. After cutting, the cutting unit is moved laterally, the upper guide pipe 31 is lowered, and the lower end portion is inserted into the wire track 49.

As shown in FIGS. 1 and 4, the lower wire electrode guide part 60 is disposed below the upper wire electrode guide part 40, and a lower machining liquid nozzle 66 that sprays a machining liquid onto the workpiece 51 during electric discharge machining, A lower die 63 disposed in the lower machining liquid nozzle 66 for positioning the wire electrode 1 during electric discharge machining, and a lower portion disposed below the lower die 63 for contacting the wire electrode 1 and supplying current to the wire electrode 1 The lower guide 64 includes a power supply 62, an upper guide 64 b disposed on the upper side of the lower power supply 62, and a lower guide 64 a disposed on the lower side, and guides the wire electrode 1 so as to contact the lower power supply 62. And a lower guide block 61 for holding them.

As shown in FIG. 1 and FIG. 4, the lower wire electrode feeding section 70 has a lower roller 72 that changes the feeding direction of the wire electrode 1 and a negative pressure for feeding the wire electrode 1 from the lower die 63 to the lower guide 64. An aspirator 73 that ejects a machining fluid that is generated and sends the wire electrode 1 to the wire electrode collection unit 80, a lower guide pipe 74 that guides the wire electrode 1 to the wire electrode collection unit 80, and a lower roller block 71 that holds them. And have.

As shown in FIGS. 1, 6 and 7, the wire electrode recovery unit 80 includes

wire recovery rollers

81 a and 81 b that hold and pull the wire electrode 1, a pipe end 82 that separates the wire electrode 1 and the processing liquid, Have.

The wire electric discharge machining apparatus 100 according to the embodiment generates a discharge by applying a pulse voltage between the wire electrode 1 and the workpiece 51 while running the wire electrode 1 in the wire electrode running system. The upper wire electrode guide part 40 and the lower wire electrode guide part 60 are moved relative to each other in a sawtooth shape to process the workpiece 51 into a desired shape.

Next, the wire electrode connection method of the wire electric discharge machining apparatus 100 will be described with reference to FIGS. As shown in FIG. 3, the upper guide block 41 of the upper wire electrode guide part 40 is formed with a suction passage 41a communicating with the lower side of the lower guide 44b. A suction device 48 is connected to the suction passage 41a. The suction device 48 sucks air in the wire electrode passage.

As shown in FIG. 2, the upper guide block 41 of the upper wire electrode guide section 40 is provided with a nozzle passage 98 connected to the jet nozzle 45, and the nozzle passage 98 is connected to the jet nozzle via a switching valve 97. A liquid pump 96 for ejecting the machining fluid from 45 is connected. The liquid pump 96 sucks the processing liquid from the processing liquid tank 99. Further, a suction device 95 that sucks air in the wire electrode passage from the lower side of the upper die 43 is connected to the nozzle passage 98 via a switching valve 97.

Between the upper guide 44a and the upper power supply 42, a sub guide 47a is disposed as a member that fills the gap between them. Between the lower guide 44b and the upper die 43, an adapter 47b is disposed as a member that fills the gap between them. Since the member for filling the gap is arranged, when the air in the wire electrode passage is sucked by the

suction devices

48 and 95, the air outside the passage is sucked and the suction efficiency is not lowered.

The

suction devices

48 and 95, the liquid pump 96, the switching valve 97, a pulse motor (not shown) that rotates the feed roller 21, and an air pump (not shown) that sends air to the guide pipe head 32 are controlled by the NC device 90 of the wire electric discharge machining apparatus 100. The

When the NC device 90 issues a connection command, the control unit 92 starts a pulse motor (not shown) that rotates the feed roller 21, an air pump (not shown) that sends air to the guide pipe head 32, and an aspirator 48. The tip of the wire electrode 1 located at the lower part of the upper guide pipe 31 at the start of connection is sent to the feed roller 21 (feed speed at the time of connection: 5000 mm / min) and approaches the upper guide 44a.

At this time, since the air flow rate supplied from the guide pipe head 32 and the air flow rate sucked by the suction device 48 are balanced, the air blown out from the upper guide pipe 31 rebounds at the pipe outlet (that is, the upper guide 44a). No, air does not convect in the upper guide pipe 31 to prevent the wire electrode 1 from being fed, and the tip of the wire electrode 1 passes through the upper guide 44a.

The determination unit 91 of the NC device 90 determines the position of the tip end portion of the wire electrode 1 from the rotation amount of the feed roller 21, and when the tip end portion of the wire electrode 1 passes through the upper guide 44a, the control unit 92 is instructed and suctioned. The suction of the device 48 is stopped, the suction by the suction device 95 is started, and the air in the wire electrode passage is sucked from the lower side of the upper die 43. At this time, the rotation of the feed roller 21 is slowed or stopped.

After a lapse of a certain time from the start (start) of suction by the suction device 95, the suction by the suction device 95 is stopped, the switching valve 97 is switched, the liquid pump 96 is connected to the nozzle passage 98, and the processing liquid to the nozzle passage 98 is supplied. While starting supply, the feed roller 21 is rotated and the wire electrode 1 is sent out. The liquid pump 96 sucks the processing liquid from the processing liquid tank 99. The machining liquid ejected from the jet nozzle 45 is ejected downward from the upper machining liquid nozzle 46, sucks the wire electrode 1 and sends it downward, and the lower end of the wire electrode guide passes through the machining start hole of the workpiece 51. Send to part 60.

When the tip of the wire electrode 1 passes through the lower power supply 62 of the lower wire electrode guide 60, a sensor (not shown) detects this and sends a detection signal to the determination unit 91 of the NC device 90. The determination unit 91 determines the position of the tip of the wire electrode 1 and instructs the control unit 92 to stop the supply of the processing liquid to the jet nozzle 45 by the liquid pump 96.

Next, a characteristic configuration of the wire electric discharge machining apparatus 100 according to the embodiment will be described. As shown in FIG. 1, the NC device 90 is configured to determine the arrival position of the tip of the wire electrode 1 during the wire electrode 1 connection work, and the liquid pump based on the arrival position determined by the determination unit 91. And a control unit 92 for controlling the discharge flow rate of 76 and the suction flow rate of the aspirator 86.

As shown in FIGS. 1 and 6 to 8, when the NC device 90 issues a connection command, the determination unit 91 determines the start of connection, and the control unit 92 controls the liquid pump 76 to control the extremely fine wire electrode 1. Is collected at a flow rate sufficient to be conveyed in the lower guide pipe 74 (for example, 6 l / min) and is sent into the lower guide pipe 74 through the aspirator 73. At the same time, the control unit 92 controls the aspirator 86 to obtain a suction flow rate (for example, a flow rate of 5 l / min obtained by subtracting a fall flow rate of 1 l / min falling in the drain pipe 85 from the recovery flow rate of 6 l / min). Inhale. Since the collection flow rate and the suction flow rate are balanced, the machining liquid does not pass through the pipe end 82 and wet the

wire collection rollers

81a and 81b.

When the tip of the wire electrode 1 reaches the lower power supply 62 of the lower wire electrode guide section 60, a sensor (not shown) detects this and sends a detection signal to the determination section 91 of the NC device 90. The NC device 90 counts the distance until the tip of the wire electrode 1 reaches before the pipe end 82 by the rotation detection unit of the feed roller 21 from the rotation number and the outer diameter of the rotation detection unit, and the determination unit 91 reaches If it judges, the control part 92 will control the liquid pump 76, and will reduce a collection | recovery flow volume to 3 l / min. At the same time, the control unit 92 controls the suction device 86 to adjust the suction flow rate, and the flow rate at which the fine wire electrode 1 is not sucked into the suction unit 82a (see FIG. 7) (for example, from the recovered flow rate 3 l / min to the drain pipe 85 Is reduced to a flow rate of 2 l / min (subtracting the drop flow rate of 1 l / min). Even at this flow rate, the recovery flow rate and the suction flow rate are balanced, so that the machining liquid does not pass through the pipe end 82 to wet the

wire recovery rollers

81a and 81b. It is known that when the recovery flow rate is 4 l / min or more, the wire electrode 1 is sucked to the suction portion 82a of the pipe end 82 and protrudes out of the path. Therefore, the recovery flow rate is set to 3 l / min with a margin.

When the tip of the wire electrode 1 passes through the pipe end 82 and is fed to the

wire collection rollers

81a and 81b, the wire electrode feed speed of the

wire collection rollers

81a and 81b is faster than the feed speed of the feed roller 21. Is pulled to increase the rotation speed. The determination unit 91 of the NC device 90 determines this, issues a carry-out completion command, starts a timer, and after a certain amount of play time has elapsed, cancels the connection command and the carry-out completion command. The aspirator 86 is stopped.

According to the wire electric discharge machining apparatus 100 of the embodiment described above, the

wire collection rollers

81a and 81b of the wire electrode collection unit 80 are not wetted when the ultrafine wire electrode 1 is connected, and the ultrafine wire electrode 1 is connected. The wire electrode 1 is not sucked into the suction part 82a.

DESCRIPTION OF SYMBOLS 1 Wire electrode, 10 Wire electrode holding | maintenance part, 11 Bobbin, 12a, 12b, 12c Pulley, 21 Feed roller, 22a, 22b Pinch roller, 30 Upper wire electrode feed part, 31 Upper guide pipe, 32 Guide pipe head, 40 Upper wire Electrode guide part, 41 Upper guide block, 41a Suction passage, 42 Upper supply electron, 43 Upper die, 44 Upper guide, 44a Upper guide, 44b Lower guide, 45 Jet nozzle, 46 Upper machining liquid nozzle, 47a Sub guide, 47b Adapter, 48 Aspirator, 49 Wire track, 51 Workpiece, 60 Lower wire electrode guide, 61 Lower guide block, 62 Lower power supply, 63 Lower die, 64 Lower guide, 64a Lower guide, 64b Upper guide, 70 Lower wire electrode feed part, 71 Lower roller 72, Lower roller, 73 Aspirator, 74 Lower guide pipe, 76 Liquid pump, 80 Wire electrode recovery part, 81a, 81b Wire recovery roller, 82 Pipe end, 82a Suction part, 85 Drain pipe, 86 Suction machine, 90 NC Device, 91 determination unit, 92 control unit, 95 suction device, 96 liquid pump, 97 switching valve, 98 nozzle passage, 99 working fluid tank, 100 wire electric discharge machining device.

Claims

A lower wire electrode guide portion having a lower die for positioning a wire electrode during electric discharge machining, and a lower supply electrode disposed below the lower die and in contact with the wire electrode to supply current to the wire electrode;
A wire electrode collection unit having a wire collection roller for holding and pulling the wire electrode, and a pipe end for separating the wire electrode and the processing liquid;
An aspirator that is disposed between the lower wire electrode guide part and the wire electrode recovery part and ejects a processing liquid that sends the wire electrode to the wire electrode recovery part, and a lower guide pipe that guides the wire electrode to the wire electrode recovery part A lower wire electrode feed section having
A liquid pump that supplies the aspirator with a machining fluid having a recovery flow rate sufficient to transport the wire electrode in the lower guide pipe;
An aspirator for sucking a machining fluid corresponding to the recovered flow rate from the pipe end;
At the time of wire electrode connection work, a determination unit that determines that the tip of the wire electrode has reached before the pipe end, and the discharge flow rate of the liquid pump and the suction flow rate of the suction device are determined based on the determination of the determination unit. A control unit for reducing the wire electrode from a recovery flow rate and a suction flow rate sufficient to convey the wire electrode in the lower guide pipe to a recovery flow rate and a suction flow rate at which the wire electrode is not sucked into the suction portion of the pipe end. When,
A wire electric discharge machining apparatus comprising:
The wire electric discharge machining apparatus according to claim 1, wherein a flow rate at which the wire electrode is not sucked into the suction portion of the pipe end is 2 l / min or less.