JP2002239845A - Electric discharge machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive and compact electric discharge machine that uses a dipping method of dividing a workpiece in machining liquid, has reliability enduring a long-time continuous operation, sufficient dividing accuracy, and high operability, reduces load on an operator, and is adequate to an unmanned operation at night. SOLUTION: A dividing mechanism for dividing the workpiece placed in a machining tank 8 of the electric discharge machine in the dipped state in the machining liquid 9 comprises a driving part 21 and a part 26 for gripping and rotating the workpiece. The former is disposed outside the liquid level 10 of the machining liquid 9, the latter is disposed in the machining liquid 9, and the both are mechanically interconnected with a timing belt 31 or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric discharge machine for machining a workpiece while immersing the workpiece in a machining fluid.

[0002]

2. Description of the Related Art In recent years, electric discharge machining techniques have rapidly advanced, and die-sinker electric discharge machines and wire electric discharge machines have been put to practical use in many fields. In an electric discharge machine, the gap between the electrode and the workpiece, which are opposed to each other with a small gap, is filled with a machining fluid of oil or water, and innumerable sparks are generated in the gap to accumulate fine electrolytic corrosion. Processing is performed.

[0003] The supply of the working fluid is performed by either a method of continuously applying the working fluid between the electrode and the workpiece or a method of immersing the electrode and the workpiece in the working fluid. ing. The latter immersion method has the advantages that the processing liquid always exists between the electrode and the workpiece, the processing reaction proceeds stably, and even when oil is used as the processing liquid, there is little danger of fire. Therefore, the burden on the operator can be reduced, and further, the suitability for unmanned continuous operation is high.

[0004] On the other hand, in a workpiece to be subjected to electric discharge machining, the circumference is divided at a predetermined angle, such as a multi-blade cutting tool such as a cutter blade or a tip saw, or a gear, and the same shape is formed. There is a thing which has the tooth tip repeatedly. When electrical discharge machining is performed on these tooth tips, the workpiece is fixed to the rotating shaft, rotated by a predetermined angle using an indexing mechanism, fixed once there, the electrodes are brought closer, and electrical discharge machining is performed. When the machining of one tooth tip is completed, the indexing mechanism is operated again, the workpiece is rotated and fixed at a predetermined angle, and the electric discharge machining of the next tooth tip is repeated.

Conventionally, as an indexing mechanism used for such an indexing operation, a manual indexing table as shown in FIG. 4, a tooth feeder with a feed claw as shown in FIG. 5, or a controller as shown in FIG. Rotary tables and the like that can be automatically indexed have been used. In the manual indexing table shown in FIG. 4, the operator releases the stopper of the indexing table and cuts the notch which rotates integrally with the workpiece each time one tooth tip is processed. It was necessary to rotate the disc by one notch and operate the stopper again, and the work load was large, and it was difficult for one operator to operate a plurality of electric discharge machines as well as unmanned operation. When combined with an immersion electric discharge machine, which immerses the electrode and workpiece in the machining fluid, the operator must use the machining fluid before finishing one tooth and moving on to the next tooth. It is necessary to refill the working tank with the working liquid again after operating the indexing table and proceeding one notch after lowering the liquid level at least partially from the processing tank. The time and effort required to do so is further added.

Similarly, when the immersion method is adopted, a tooth feeder using a feed claw or a rotary table of automatic indexing has a driving unit composed of pneumatic or hydraulic equipment, or electric parts, and therefore, it is difficult to use the same. Considering the liquid-proof (water-proof or oil-proof) of the drive unit, it becomes a problem where to place it.

In the case of the tooth feeder using the feed pawl shown in FIG. 5, the drive unit can be set on the level of the working liquid by increasing the length of the feed pawl. In this case, it is structurally possible if the diameter of the workpiece is almost constant and the position of the feed teeth does not become too deep from the liquid surface, but in actuality, the diameter of the workpiece is large to small. Yes, since the rotation axis is usually fixed at a certain depth from the liquid surface, it is extremely long to feed the teeth of the smallest diameter workpiece at a deep position away from the liquid surface. Feeding claws are required, and problems arise in strength and feeding accuracy. Further, in the case of the feed claw, there is a fundamental defect that it is impossible to feed in principle when the workpiece is a cutter blade having two teeth at an interval of 180 degrees.

In the case of the rotary table of automatic indexing shown in FIG. 6, since the indexing operation can be performed automatically by a controller installed outside the processing liquid, it is necessary to take in and out the processing liquid as in the case of a manual indexing table. However, in general, rotary tables have built-in drive units such as servo motors and servo amplifiers to be driven. Since only a simple seal and air purging are used, the machining fluid does not fall on the rotary table as in the case of an electric discharge machine that applies a machining fluid to the electrode part. Immersion-type electric discharge machine, which can be used for a while when hydraulic pressure is not applied, but is immersed in machining fluid for a long time and continuously operated while receiving hydraulic pressure There is no track record to combine, not suitable lacking in reliability and stability. Furthermore, even rotary tables currently available on the market with inadequate liquidproofing are extremely expensive compared to ordinary specifications that do not consider liquidproofing, and are extremely large in dimensions. However, if you try to install it in a processing tank that fills the processing liquid, it will not fit in the processing tank of a commercial electric discharge machine, and it will be necessary to increase the size of the processing tank just to accommodate the rotary table. The EDM equipment itself becomes large, causing the disadvantage of occupying a large area of the factory,
Therefore, the cost also increases.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a dipping-type electric discharge machine for indexing a workpiece in a machining fluid, which can be used for a long continuous operation. An object of the present invention is to provide an inexpensive and compact electric discharge machine which has endurable reliability, sufficient indexing accuracy, and excellent operability, has a small burden on an operator, and is suitable for unmanned operation at night. .

[0010]

In order to solve the above problems, an immersion electric discharge machine for immersing a workpiece in a working fluid according to the present invention is provided with an immersion method. The indexing mechanism for rotating the indexing mechanism is installed outside of the machining fluid, and the machine between the indexing mechanism installed in the machining fluid to grip and rotate the workpiece Characterized by the fact that they are combined.

Unlike a conventional rotary table on the market, a drive part for rotating and driving a shaft for indexing and a part for gripping and rotating a workpiece with the shaft are not integrally formed.
In the liquid, only the latter part, that is, the shaft that rotates the workpiece, the bearing mechanism that supports the shaft, the mechanism that grips the workpiece on the shaft, etc. are installed, and if placed in the liquid, complete Electrical parts such as servo motors and servo amplifiers that require liquid-proof specifications, and the former parts including pneumatic and hydraulic devices, etc., are installed outside the machining fluid. Then, by mechanically connecting the two, the operation of indexing the workpiece in the working fluid becomes possible by driving from outside the working fluid.

As a mechanical connection between a driving portion of the indexing mechanism and a portion for gripping and rotating the workpiece (hereinafter, referred to as a “grip / rotation portion”), the rotation of the former shaft is performed by the latter. Because it is transmitted to the shaft, gear drive, chain drive,
Various combinations, such as a combination of a normal belt and a pulley, can be considered, but the indexing accuracy to be expected, the degree of freedom in selecting the installation location of each of the two parts to be combined, and the timing from the viewpoint of cost. The combination of a belt and a timing pulley is most desirable. The timing belt is a toothed transmission belt that takes advantage of the advantages of gears and V-belts.
Since there is no slip, rotation can be transmitted accurately and accurately, and there is little noise.

[0013] By adopting the above configuration, all the electrical components and pneumatic / hydraulic devices which need liquid-proof specifications when installed in the working fluid are installed outside the working fluid, and are general-purpose general-purpose products. Among them, those whose reliability has been proved by a sufficient operation record can be selected and applied as they are, so that it is inexpensive, compact, and reliable enough to withstand continuous operation for a long time. On the other hand, in combination with a controller, the same operability and indexing accuracy as those of a conventional automatic indexing rotary table can be obtained. In addition to dividing the circumference evenly, it is also possible to perform an indexing operation at any unequal angle. In addition, since there is no need to operate the stopper or feed or remove the machining fluid during the gear feeding, it does not require much labor and time, so the burden on the operator can be reduced, and the automatic indexing function combined with the controller is provided. If it is combined with a device for automatically changing the workpiece, it can be easily applied to unmanned operation at night.

Further, since the gripping / rotating portion of the indexing mechanism installed in the working fluid is only a part of the conventional rotary table, the indexing mechanism can be compared with a conventional rotary table which does not consider waterproof (liquidproof). It can be made much smaller and does not take up space in the processing tank. Therefore, in many cases, it can be easily installed in the machining tank of a commercially available immersion electric discharge machine, and even if the machining tank needs to be modified slightly, it is not necessary to greatly increase its size. In addition, it is possible to suppress the increase in the size of the electric discharge machining equipment itself, the occupation of the space in the factory, and the increase in the cost associated therewith.

Further, the electric discharge machine of the present invention is particularly suitable when the workpiece is a multi-cutting cutting tool. recent years,
There are many cutting tools, such as cemented carbide and diamond, which have high hardness and are difficult to manufacture and re-polish using conventional machining methods. Die-sinker EDMs and wire EDMs that can machine regardless of the hardness of the workpiece The application has attracted attention. In applying these electric discharge machines to the machining of multi-edged cutting tools using such materials, it is essential to provide an indexing mechanism that can reduce the burden on operators and withstand unmanned operation at night. In particular, the electric discharge machine of the present invention has high suitability.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. The present invention is not limited to such an embodiment, it is needless to say may make various changes to the specific structure within the scope of the present invention.

FIG. 1 is an overall view of an electric discharge machine according to the present invention, FIG. 2 is a detailed view of an indexing mechanism, and FIG. 3 is an explanatory view showing a state in which a workpiece is attached to the indexing mechanism. In this embodiment, a wire electric discharge machine will be described as an example, but the present invention can be similarly applied to a die-sinking electric discharge machine only with a difference in the shape of an electrode and a device for supporting and driving the electrode.

In FIG. 1, a wire 1 serving as an electrode is continuously supplied from a wire bobbin (not shown) in an upper wire supply device 2 through an upper guide 3, and is supplied to a workpiece (this figure). , Which indicates a non-attached state, is not shown in the figure, and then discharges, and then passes through the lower guide 4 and the lower guide support arm 5 to collect a wire in the main body 6 (not shown). )). A portion where electric discharge machining is performed between the wire 1 and the workpiece is housed in a machining tank 8 and immersed in a machining fluid 9.
Further, necessary control panel 11, electric panel 12, and the like are additionally provided. Lower guide 4, supporting arm 5, body 6,
The pedestal 7 is fixed, and the processing tank 8 is provided with a driving device in the main body 6 so that the relative position between the workpiece 1 fixed therein and the wire 1 as an electrode can be changed. by being adapted to be moved over the base 7 in a two-dimensional direction of X-axis -Y-axis, the upper guide 3 fixed thereto and wire feeder 2, that tapering the wire 1 of the discharge portion Can be moved in a two-dimensional direction of the U-axis and the V-axis by a driving device in the main body 6 so as to perform the operation.

An indexing mechanism is provided in order to process a workpiece having a shape like a multi-blade cutting tool with a wire electric discharge machine employing this immersion method. First, the drive part 21 of the indexing mechanism is fixed to the upper part of the processing tank 8. The fixed position is above the liquid level 10 so that the working liquid 9 is not applied. On the other hand, the gripping / rotating portion 26 is fixed to the processing tank 8 by the support member 15 at a position below the liquid surface 10 of the processing liquid 9 and near the wire 1 as an electrode. The drive part 21 and the gripping / rotating part 26 of the indexing mechanism are mechanically connected by a combination of a timing belt 31 and a timing pulley.

[0020] FIG. 2, showing details of the indexing mechanism. The driving part 21 of the indexing mechanism fixed to the upper part of the processing tank 8 and higher than the liquid level 10 of the processing liquid includes a rotating part 22 composed of a servomotor, a servo amplifier, etc., a deceleration part 23, and a timing pulley 24. And so on. On the other hand, the gripping / rotating part 26 of the indexing mechanism fixed to the processing tank 8 by the support member 15 below the liquid level 10 of the processing liquid includes a timing pulley 27, a bearing part 28, and a shaft for mounting the workpiece. 29.

FIG. 3 shows a state in which a cutter blade 35 as a workpiece is attached to the indexing mechanism. The cutter blade 35 fixed to the shaft 29 of the gripping / rotating part 26 of the indexing mechanism with a fixing jig 36 moves the processing tank 8 on the base 7 in the X-axis-Y
By moving the shaft in a two-dimensional direction, the relative position with respect to the wire 1 as an electrode is adjusted. As an example, a case where the side surface of the cutting edge of the cutter blade is polished by electric discharge machining will be described. The consumable wire 1 is fed out from the upper guide 3 and is discharged through the lower guide 4 and the supporting arm 5 while being collected and discharged between the workpiece and the cutter blade 35. At this time, the processing tank 8 is moved on the pedestal 7 in the X-axis direction so that the wire 1 passes along the side of the blade to be polished while keeping a slight distance from the side. 1
When the wire passes, the surface to be polished is slightly receded by the electric discharge machining. Therefore, the processing tank 8 is moved in the Y-axis direction so as to feed the same, and again while moving the processing tank 8 in the X-axis direction. The second polishing is performed.

When the polishing of one cutting edge is completed, the rotating portion 22 of the drive portion 21 of the indexing mechanism starts rotating according to a control signal from the control panel. The rotational motion is reduced by the speed reduction unit 23, amplified in its rotational force, transmitted to the timing pulley 24, and further transmitted to the timing pulley 27 of the gripping / rotating part 26 by the timing belt 31. The timing pulley 27 is fixed to a shaft 29 for fixing a cutter blade 35, which is a workpiece, and the shaft 29 is supported by a bearing portion 28. Therefore, the cutter blade 35 is rotated by the same angle as the rotation angle of the timing pulley 27. It will rotate. By setting in advance in the control panel, the rotation of the rotating unit 22 is stopped at a point where the cutter blade 35 as a workpiece is rotated by a predetermined angle, in this case, 90 degrees, and fixed at that position. You. In this state, the polishing of the second blade is performed by moving the processing tank 8 on the pedestal 7 as described above while discharging between the wire 1 and the cutter blade 35. This operation a predetermined number of times, four times in this case, by repeating the polishing of all of the cutting edge of the cutter blade is finished.

By changing the settings in the control panel,
It goes without saying that it can be easily adapted from a gear having a large number of teeth to a cutter blade having only two blades. In addition, it is possible to cope with the case where the circumference is not equally divided, for example, a cutter blade having a blade at each of 60 °, 120 °, 60 °, and 120 °. Furthermore, if this electric discharge machine is combined with a device for automatically changing the workpiece, it can be used for a long time unmanned operation.

[0024]

As described above, the electric discharge machine of the immersion method according to the present invention is a reliable electric machine and pneumatic / hydraulic equipment from a general-purpose product not having a liquid-proof (waterproof or oil-proof) specification with a sufficient operation record. It can be applied as it is by selecting a material with proven properties, so it is inexpensive and compact in itself, has reliability that can withstand long-time continuous operation, and has an indexing mechanism installed in the machining fluid. The gripping / rotating part is simple and
Since it is small and does not take up space in the machining tank, it can be installed in the machining tank of a commercially available immersion electric discharge machine in many cases, and in some cases it is necessary to modify the machining tank slightly. However, there is no need to greatly increase the size of the electric discharge machining equipment, which has the effect of suppressing the increase in the size of the electric discharge machining equipment, the occupation of the space in the factory, and the accompanying increase in cost.

On the other hand, excellent operability and indexing accuracy similar to those of the conventional automatic indexing rotary table are obtained.
In addition to dividing the circumference evenly, it is also possible to index at any unequal angle, and it is not necessary to manually operate the stopper or take in and out the machining fluid when feeding the gear. This has the effect of reducing the load on the vehicle and having high suitability for unmanned driving at night.

When a combination of a timing belt and a timing pulley is used as a method for mechanically connecting the driving portion of the indexing mechanism and the gripping / rotating portion, a high indexing accuracy can be expected, and the indexing mechanism can be expected. driving part and the grip-rotating part of the freedom of each of the location of the selection is large and results in an effect that it is economical. further,
The electric discharge machine of the immersion method of the present invention is particularly suitable for machining a multi-edged cutting tool.

[Brief description of the drawings]

FIG. 1 is an overall view of an electric discharge machine according to the present invention.

FIG. 2 is a detailed view of an indexing mechanism of the electric discharge machine according to the present invention.

3 is an explanatory view showing a state of attaching the workpiece to the indexing mechanism.

FIG. 4 is an explanatory view of a conventional manual indexing table.

FIG. 5 is a conventional tooth feeder using feed claws.

FIG. 6 shows a conventional automatic indexable rotary table.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wire which is an electrode 2 Wire supply device 3 Upper guide 4 Lower guide 5 Lower guide support arm 6 Main body 7 Pedestal 8 Processing tank 9 Processing liquid 10 Level of processing liquid 11 Control panel 12 Electric panel 15 Supporting material 21 Indexing mechanism Driving part 22 Rotating part 23 Deceleration part 24 Timing pulley 26 Gripping / rotating part of indexing mechanism 27 Timing pulley 28 Bearing part 29 Shaft for attaching workpiece 31 Timing belt 35 Workpiece cutter blade 36 Fixing jig

Claims (3)

[Claims] 1. An electric discharge machine for machining a workpiece in a state where the workpiece is immersed in a machining fluid, comprising: an indexing mechanism for rotating the workpiece by a predetermined angle; An electric discharge machine characterized in that a drive portion is provided outside a machining fluid, and a portion of the indexing mechanism, which is provided in the machining fluid, grips and rotates a workpiece, and is mechanically connected to the portion. 2. A mechanical coupling between a driving portion of the indexing mechanism and a portion for gripping and rotating a workpiece, comprising a combination of a timing belt and a timing pulley. Electric discharge machine. 3. The electric discharge machine according to claim 1, wherein the workpiece is a multi-cutting cutting tool.