JPS6365457B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an electric discharge machining apparatus, particularly an electric discharge machine that prevents accidents such as explosions caused by flammable gas generated during electric discharge machining performed on a machining table placed in a machining fluid. This relates to improvements in processing equipment.

[Prior Art] It is generally known that when electric discharge machining is performed in machining fluid, sludge and flammable gas are generated. These sludge and flammable gases fill the machining table, especially when performing electrical discharge machining using a machining table, resulting in a decrease in machining performance due to the sludge, or damage or movement of the equipment due to an explosion of the flammable gas. This caused an accident.

As a conventional device of this kind, as shown in FIG.
2, an electrode 14, and a machining fluid supply device 16. The machining table 12 has a machining base 18 provided at its upper end, and the machining hole 2 of the machining base 18
A workpiece 22 facing the electrode 14 is fixed on the top surface of the workpiece 2.

The machining fluid supply device 16 includes a suction pipe 24 that sucks the machining fluid 10 from the machining table 12 and a jetting pipe 26 that spouts the machining fluid 10 onto the machining table 12.

Next, we will explain the operation of this conventional device.
The electrode 14 is brought close to the workpiece 22, and the machining fluid supply device 16 is operated to supply the jet pipe 26.
The machining liquid 10 is spouted into the machining table 12 from the machine, and at the same time, the machining liquid 10 is sucked from the machining table 12 by the suction pipe 24. At this time, the machining fluid 10 is discharged from the spout pipe 26.
The amount of suction from the suction pipe 24 is set to be larger than the amount of ejection so that the machining liquid 10 is also suctioned from the gap between the electrode 14 and the workpiece 22. When the workpiece 22 is then subjected to electrical discharge machining, sludge and flammable gas are generated, which are discharged from the suction pipe 24 to the outside of the machining table 12. Note that machining can also be performed with the amount of machining fluid 10 ejected out being greater than the amount of suction.

However, in this type of electric discharge machining equipment, it is difficult to optimize the amount of machining fluid 10 supplied and discharged to the machining table 12, and flammable gas accumulates above the suction pipe 24 in the machining table 12, causing this combustible gas to accumulate. Accidents such as equipment damage and movement due to the explosion of toxic gas had occurred.

[Summary of the Invention] The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to periodically discharge flammable gas accumulated in the upper part of the processing table and sludge accumulated in the lower part of the processing table, An object of the present invention is to provide an electrical discharge machining device that maintains machining performance and prevents accidents.

[Embodiments of the Invention] Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

First, the technology on which the present invention is based is shown in FIG. 2, and the same members as in FIG. 1 are given the same reference numerals and their explanations will be omitted.

A bottomed box-like processing table 12 provided in the processing liquid 10
, an electrode 14 , and a machining fluid supply device 16 . The processing table 12 has a processing base 18 provided at its upper end, and a non-workpiece 22 facing the electrode 14 is fixed on the upper surface of the processing hole 20 of the processing table 18. The machining liquid supply device 16 is provided with a suction pipe 24 and a jet pipe 26 between it and the machining table 12 . The ejection pipe 26 is branched into two parts via electromagnetic valves 28 and 30 on the side of the machining liquid supply device 16, and one side is a bypass pipe 32.
In addition, in the figure, 34 is a movement amount measuring device of the electrode 14, and 36 is a movement amount detection device 34, and an electromagnetic valve 2.
8, 30, etc., and 38 is a timer provided within the control box 30.

Next, to explain the operation of the device according to the illustrated example, the electrode 14 is brought close to the workpiece 22, and the machining fluid supply device 16 is activated to jet the machining fluid 10 from the jet pipe 26 into the machining table 12. At the same time, the machining liquid 10 in the machining table 12 is sucked by the suction pipe 24. At this time, the amount of suction from the suction pipe 24 is set to be larger than the amount of machining fluid 10 spouted from the jet pipe 26, and the amount of suction from the suction pipe 24 is set to
The machining fluid 10 is also sucked from the gap between the two. Thereafter, when the workpiece 22 is subjected to electrical discharge machining, sludge and combustible gas are generated in the processing table 12, but most of these sludge and combustible gas are suctioned and discharged from the suction pipe 24. However, if this electrical discharge machining is continued for a certain period of time, sludge will accumulate at the bottom of the processing table 12 and flammable gas will accumulate at the top of the processing table 12, leading to a decrease in machining performance or the risk of an accident due to an explosion. Timer 38 in control box 36
After a certain period of time, the electrode 14 moves upward by 1 mm.
At the same time, the machining fluid 10 is ejected from the bypass pipe 32 into the machining table 12, and the sludge and combustible gas inside the machining table 12 are discharged to the outside of the machining table 12. for a certain period of time,
For example, after the electrode 14 is pulled up for about 1 to 10 seconds and the discharge of sludge and combustible gas is completed, the electrode 14 approaches the workpiece 22 again, and the electromagnetic valve 30 of the bypass pipe 32 is closed.
This is to start electrical discharge machining.

In this illustrated example device, since the electrode 14 is vertically movable, flammable gas is discharged to the outside of the processing table 12 as the electrode 14 is pulled upward.
2. Explosion of flammable gas accumulated inside can be prevented and processing can be performed safely.

In addition, if the timer 38 provided in the control box 36 is set appropriately depending on the material, shape, processing conditions, etc. of the workpiece 22 and the electrode 14 is pulled up, labor saving and processing efficiency are improved, and explosions can be prevented. The risk of

Furthermore, by providing a bypass pipe 32 that spouts the machining liquid 10 into the machining table 12 when the electrode 14 is pulled up, the flammable gas can be completely discharged, and the sludge can also be discharged outside the machining table 12.
It can prevent explosions and maintain machining performance.

However, in the illustrated example apparatus, the danger of explosion due to the flammable gas accumulated before the electrode 14 is lifted still remains unresolved, and processing time is lost due to the electrode 14 being pulled up. Therefore, a further improved device to solve this problem is shown in FIG.

That is, FIG. 3 shows a preferred embodiment of the present invention, and the same members as those in FIG. 2 are designated by the same reference numerals and their explanations will be omitted. The suction pipe 24 is formed by providing an L-shaped nozzle 42 at the tip inside the processing table 12 via a flexible pipe 40 that can freely move forward and backward and rotate. In addition, numeral 44 in the figure is a stopper between the suction pipe 24 and the processing table 12. Further, a safety valve 46 is provided on the side of the processing table 12. This safety valve 46 is an escape hole 4 bored in the processing table 12.
8, a mechanical button 50 that opens the mechanical button 8;
a spring 52 that presses the spring 52 against the relief hole 48; and a support member 54 that supports the spring 52 in the relief hole 48.
and an adjustment screw 56 for adjusting the strength of the spring 52.
It is formed from.

Next, the operation of the device according to the present invention will be explained. While the electrode 14 is brought close to the workpiece 22, the machining fluid supply device 16 is activated to spray the machining fluid 10 into the machining table 12 from the spouting pipe 26. ,
At the same time, the machining liquid 10 in the machining table 12 is sucked from the suction pipe 24. At this time, the suction pipe 2
No. 4 nozzle 42 is positioned. Thereafter, when the workpiece 22 is subjected to electrical discharge machining, sludge and combustible gas are generated, but most of these sludge and combustible gas are suctioned and discharged from the suction pipe 24. However, if this electric discharge machining is continued for a certain period of time, sludge will accumulate in the lower part of the processing table 12, and flammable gas will accumulate mainly in the processing hole 20 in the upper part of the processing table 12. Therefore, the timer 38 in the control box 36 causes the electrode 14 to be pulled upward by 1 mm to 10 mm after a certain period of time has elapsed, and the machining fluid 10 is spouted into the machining table 12 from the bypass pipe 32 to Sludge and flammable gas are discharged to the outside of the processing table 12. After being lifted from the electrode 14 for a certain period of time, for example, about 1 to 10 seconds, and the discharge of sludge and combustible gas is completed, the electrode 14 approaches the workpiece 22 again, and the electromagnetic valve 30 of the bypass pipe 32 is closed. Then, electrical discharge machining begins.

In the present invention, the tip position of the suction pipe 24 is formed so that it can be changed from the outside of the processing table at least in the width direction of the electrode. The tip of the suction pipe can be set at a certain position, and processing can be performed with almost no flammable gas accumulating in the processing table 12. Therefore, there are almost no accidents caused by flammable gas explosions, and there are no accidents such as equipment damage.
Alternatively, even if the flammable gas were to explode, since the processing table 12 is provided with the safety valve 46, the pressure caused by the explosion would be released to the outside of the processing table 12, and the entire apparatus would not be damaged.

If a flexible pipe 40 is provided in the middle of the suction pipe 24, the nozzle 42 at the tip of the suction pipe 24 can move forward and backward and rotate freely, so the nozzle 42 can be positioned at a position where flammable gas is likely to accumulate, improving safety. further improves.

Further, if the safety valve 46 is formed as a spring type which opens at 0.5 to 2 kg/cm ² , not only the structure is simple but also damage due to explosion can be completely prevented.

[Effects of the Invention] As described above, according to the present invention, it is possible to reliably discharge the flammable gas accumulated in the processing table even before the electrode is pulled up.

[Brief explanation of drawings]

FIG. 1 is a system diagram of a conventional device, FIG. 2 is a system diagram of a device on which the present invention is based, and FIG. 3 is a system diagram showing another embodiment of the device of the present invention. The same members in each figure are given the same reference numerals, 10 is the machining fluid, 12 is the machining table, 14 is the electrode, 16 is the machining fluid supply device, 24 is the suction pipe, 42 is the nozzle, 4
6 is a safety valve.

Claims (1)

[Scope of Claims] 1. A processing hole is provided on the upper surface, a space is formed in which a processing fluid accumulates, a processing table is provided in which a workpiece is fixed on the processing hole, and is placed in the processing fluid; A machining liquid that has a spouting pipe that spouts out and a suction pipe that sucks a larger amount of machining fluid than the amount of machining fluid spouted from the spouting pipe, and supplies and discharges the machining fluid into the inside of the machining table. A supply device, which controls the vertical movement of an electrode placed opposite to the workpiece, and when the electrode is controlled to be pulled up, sprays a larger amount of machining liquid from the spout pipe into the processing table than usual. a control box for controlling the machining liquid supply device so as to control the machining liquid supply device; and a flexible pipe that constitutes at least a part of the suction pipe and allows the tip position of the suction pipe to move forward and backward and rotate freely within the machining table. electrical discharge machining equipment. 2. The electric discharge machining apparatus according to claim 1, wherein the control box temporally controls the vertical movement of the electrode. 3. The electrical discharge machining apparatus according to claim 1, wherein the machining fluid supply device is provided with a bypass pipe that spouts machining fluid when the electrode is pulled up. 4. The electric discharge machining apparatus according to claim 1, characterized in that a safety valve is attached to the machining table. 5. The electric discharge machining apparatus according to claim 4, wherein the safety valve is formed as a spring-type safety valve that opens at 0.5 to 2 kg/cm ² . 6. The apparatus according to any one of claims 1 to 5, characterized in that the tip of the machining liquid supply pipe in the machining table is formed in an L-shape, and the suction pipe is formed so as to be freely forward and backward and rotatable. Electrical discharge machining equipment.