JP7490011B2 - Machining fluid injection device and machining fluid injection method - Google Patents

Description

This disclosure relates to a machining fluid injection device and a machining fluid injection method.

When machining parts using a die-sinking EDM, it is essential to efficiently remove sludge in order to prevent secondary discharge defects caused by sludge. Here, the part to be machined is the workpiece or workpiece. Secondary discharge defects are defects in which parts other than the machining part are melted and processed by passing electricity through the machining powder.
In the prior art, a jet unit is connected to an oil supply device via a flexible cable, and the position of the jet unit is adjusted according to the position of the movable spindle unit to which the electrode is attached, and machining fluid is sprayed onto the electrode and the workpiece to cool the workpiece and remove sludge. Here, the jet unit is made of a coolant nozzle. In this case, the jet position and jet direction of the jet unit are adjusted each time before and during machining so that the machining fluid is appropriately sprayed into the gap between the electrode and the workpiece.
In addition, in the conventional technology, the machining fluid is injected from only one nozzle, which makes it difficult to discharge sludge. This can lead to problems caused by secondary discharge. In addition, when the workpiece has a deep groove shape that makes it difficult to discharge sludge, the machining process must be interrupted to clean the sludge. This requires a lot of machining time.

Japanese Patent Application Laid-Open No. 6-134625

Patent Document 1 also discloses a configuration in which there are multiple injection holes for injecting machining fluid. However, this configuration has the problem that the position of the injection hole does not change in conjunction with the change in the position of the movable spindle part, so when the movable spindle part of the die-sinking electric discharge machine moves, the position of the injection hole needs to be adjusted separately.

The present disclosure aims to provide a machining fluid injection device for a die-sinking electric discharge machine that is relatively easy to discharge sludge from and does not require separate adjustment of the position of the injection hole when the movable spindle part of the die-sinking electric discharge machine moves.

The machining fluid injection device according to the present disclosure comprises:
A machining fluid injection device for injecting machining fluid in a die-sinking electric discharge machine,
A plurality of injection holes for injecting machining fluid toward an electrode provided on the die-sinking electric discharge machine are formed radially around the electrode, and the die-sinking electric discharge machine is provided with an injection unit that moves in conjunction with a movable main spindle unit provided on the die-sinking electric discharge machine.

According to the present disclosure, multiple injection holes for injecting machining fluid toward the electrode are formed radially around the electrode of the die-sinking electric discharge machine, and machining fluid is injected toward the electrode from the multiple injection holes. In addition, the injection section moves in conjunction with the movable spindle section of the die-sinking electric discharge machine. Therefore, according to the present disclosure, it is possible to provide a machining fluid injection device for a die-sinking electric discharge machine, which is relatively easy to discharge sludge from, and does not require separate adjustment of the position of the injection hole when the movable spindle section of the die-sinking electric discharge machine moves.

1 is a diagram showing an example of the configuration of a die-sinking electric discharge machine 10 according to a first embodiment; 1A is a diagram showing an example of the configuration of a machining fluid ejection device 100 according to a first embodiment, and FIG. 1B is a cross-sectional view of the ejection unit 210. FIG. 1A and 1B are diagrams showing an example of the configuration of a machining fluid ejection device 100 according to a first embodiment, in which FIG. 1 is a diagram showing a configuration example of a machining fluid ejection device 100 according to a first embodiment; FIG. 2 is a diagram showing a configuration example of a fuel supply device 300 according to the first embodiment. 5A to 5C are diagrams for explaining the effects of the machining fluid ejection device 100 according to the first embodiment.

In the description of the embodiments and drawings, the same elements and corresponding elements are given the same reference numerals. Descriptions of elements given the same reference numerals are omitted or simplified as appropriate.

Embodiment 1.
Hereinafter, the present embodiment will be described in detail with reference to the drawings.

***Configuration Description***
Fig. 1 shows an example of the configuration of a die-sinking electric discharge machine 10 according to an embodiment of the present invention. As shown in Fig. 1, the appearance of the die-sinking electric discharge machine 10 is similar to that of a conventional die-sinking electric discharge machine.

FIG. 2 shows an example of the configuration of the machining fluid injection device 100 according to the present embodiment. FIG. 2(a) shows the appearance of the vicinity of the injection unit 210 during machining. The machining fluid injection device 100 injects machining fluid 310 in the die-sinking electric discharge machine 10. In the die-sinking electric discharge machine 10, a method of injecting machining fluid 310 from a plurality of injection holes 215 formed in the injection unit 210 toward the electrode 50 provided in the die-sinking electric discharge machine 10 corresponds to a machining fluid injection method. FIG. 2(b) shows a cross-sectional view of the injection unit 210. The cross-sectional view shows a cross-section that divides the support portion 212 into two equal parts, and shows a state in which the injection unit 210 is cut by a cross-section that passes through the central axis of the annular portion 211. The central axis of the annular portion 211 is an axis perpendicular to a plane that passes through the bottom surface 217, and corresponds to an axis that passes through the center of the shape equivalent to a circle formed by the annular portion 211. In FIG. 2B, for the sake of explanation, a machining fluid inlet pipe 230, an oil supply device 300, and a piping hose 400 are added in a schematic manner to the front cross-sectional view.
Fig. 3 shows an example of the configuration of the machining fluid injection device 100 according to this embodiment. Fig. 3(a) shows the machining fluid injection device 100 attached to the die-sinking electric discharge machine 10. Fig. 3(b) shows a front cross-sectional view corresponding to Fig. 3(a). The front cross-sectional view shows the state of a cross section passing through the central axis of the electrode 50.
FIG. 4 shows an example of the configuration of a machining fluid ejecting device 100 according to this embodiment.
FIG. 5 shows an example of the configuration of a fuel supply device 300 according to this embodiment.
The machining fluid ejection device 100 will be described below with reference to FIGS.
As shown in Fig. 4, the die-sinking electric discharge machine 10 is composed of a movable spindle portion 11 and a movable spindle portion 12, an electrode holder 51 detachably attached to the movable spindle portion 12, an electrode 50 attached to the electrode holder 51, an oil supplying device 300, and a liquid receiving portion 600. The movable spindle portion 11 is movable in the X-axis direction and the Y-axis direction. The movable spindle portion 12 is movable in the Z-axis direction. A hose 650 provided on the liquid receiving portion 600 is connected to an oil inlet of the oil supplying device 300.
The machining fluid ejection device 100 is composed of a machining fluid ejection jig 200 and a piping hose 400 attached to a discharge hole 305 of an oil supply device 300 .

The machining fluid ejection jig 200 is attached to the movable spindle portion 12 of the die-sinking electric discharge machine 10 to which the electrode holder 51 is attached. The machining fluid ejection jig 200 includes an ejection portion 210 and an attachment portion 220.
The ejection portion 210 is composed of an annular portion 211 and a support portion 212. The annular portion 211 and the support portion 212 are integrally formed.
The annular portion 211 has an annular shape. An annular inner surface 216 of the annular portion 211 surrounds the periphery of the electrode 50 with a gap therebetween. A plurality of injection holes 215 are formed in the annular portion 211. The injection hole 215 is a general term for the injection hole 215a and the injection hole 215b. The injection hole 215a is provided in the annular inner surface 216 and is also called an upper injection hole. The injection hole 215b is provided in the bottom surface 217 and is also called a lower injection hole.
The support portion 212 is attached to the annular portion 211 and supports the annular portion 211 .
The attachment portion 220 attaches the injection portion 210 to the movable spindle portion 12. At this time, the support portion 212 is fastened to the attachment portion 220. The vertical position of the annular portion 211 may be changed by changing the position at which the support portion 212 and the attachment portion 220 are fastened. The attachment portion 220 may be detachably attached to the movable spindle portion 12 included in the die-sinking electric discharge machine 10. A magnetic force may be used when attaching the attachment portion 220 to the movable spindle portion 12.
As a specific example, the ejection portion 210 and the attachment portion 220 are formed by integral molding of resin using a 3D (3-Dimension) printer using a resin material having a specific gravity that does not apply a load to the movable main shaft portion 12 .
A machining fluid inlet hole 214 is formed in a mounting portion side surface 213 which is a part of the support portion 212 .
A machining fluid inlet pipe 230 that fits into the machining fluid inlet hole 214 is removably attached to the machining fluid inlet hole 214 .
The machining fluid inlet pipe 230 is connected to the discharge hole 305 through a piping hose 400. The machining fluid 310 is supplied to the machining fluid inlet pipe 230 from an oil supply device 300 via the piping hose 400. That is, the machining fluid 310 flows into the machining fluid inlet pipe 230. The machining fluid 310 is also called machining oil.
A specific example of the piping hose 400 is a flexible cable.

Here, the process of recovering the machining fluid 310 by the oil supply device 300 will be described. First, the machining fluid 310 injected from the injection hole 215 is injected onto the machining part of the workpiece 500. Next, the machining fluid 310 overflowing from the machining part of the workpiece 500 is recovered by the liquid receiving part 600. Next, the machining fluid 310 recovered by the liquid receiving part 600 is recovered into the in-facility tank 301 through the hose 650 and the suction hole 306. Next, the machining fluid 310 recovered into the in-facility tank 301 is filtered by the filter 302 and then discharged from the discharge hole 305 by the pump operation of the oil supply device 300. The workpiece 500 is a machined part. FIG. 2A shows the state in which the machining fluid 310 is injected from a plurality of injection holes 215 onto the machining part of the workpiece 500.
The oil supplying device 300 stores machining fluid 310. The oil supplying device 300 uses a pump to suck up the machining fluid 310 from an in-facility tank 301. The in-facility tank 301 is provided with a filter 302 that circulates the recovered machining fluid 310 and filters out impurities such as machining powder.

The injection part 210 is disposed around the electrode 50 as shown in Fig. 3(a). In the injection part 210, a plurality of injection holes 215 are formed radially on the circumference on each of an annular inner surface 216 and a bottom surface 217 as shown in Fig. 2(b). The injection part 210 moves in conjunction with an electrode holder 51 provided in the die-sinking electric discharge machine 10.
The annular inner surface 216 is a region that surrounds the electrode holder 51 and is the surface of the annular portion 211 that faces the electrode 50 .
The annular outer surface 241 is the surface of the annular portion 211 that faces the annular inner surface 216 .
The bottom surface 217 is the bottom surface of the surface of the annular portion 211 in the vertical direction.
The upper surface 242 is the upper surface of the annular portion 211 in the vertical direction.
Around the electrode 50 included in the die-sinking electric discharge machine 10, the machining fluid 310 is injected from each of the multiple injection holes 215 toward the electrode 50. The multiple injection holes 215 may be composed of multiple upper injection holes and multiple lower injection holes. In the annular inner surface 216, the multiple upper injection holes are formed radially around the electrode 50. In the bottom surface 217, the multiple lower injection holes are formed radially around the electrode 50. The angle between the direction in which each of the multiple upper injection holes injects the machining fluid 310 and the central axis 910 is 40 degrees or more and 60 degrees or less. The central axis 910 is the central axis of the annular portion 211, and is coaxial with the axis of the movable main shaft portion 12 and the central axis of the electrode 50. The angle between the direction in which each of the multiple lower injection holes injects the machining fluid 310 and the central axis 910 is 20 degrees or more and 40 degrees or less.
The cross-sectional shape of the injection hole 215 is, for example, a circle, a rectangle, or another polygon. The diameter or the length of the short side of the cross-section of the injection hole 215 is appropriately set between about 2 mm and 7 mm. The cross section of each injection hole 215 is a plane perpendicular to the direction in which the machining fluid 310 is injected from each injection hole 215.
In the annular inner surface 216, the injection holes 215 are preferably arranged at eight positions evenly along the circumference of the annular inner surface 216. That is, the number of the multiple upper injection holes is preferably eight, and the multiple upper injection holes are preferably formed at equal intervals on the annular inner surface 216. In addition, each injection hole 215 is preferably formed around the electrode 50, facing the outer circumferential surface of the electrode lower part 52.
It is preferable that the injection holes 215 are evenly arranged at eight positions on the circumference of the bottom surface 217. That is, the number of the lower injection holes is eight, and the lower injection holes are preferably formed at equal intervals on the bottom surface 217. It is also preferable that each injection hole 215 is formed facing the machined portion where a narrow deep groove shape is to be formed. The machined portion is the portion of the workpiece 500 that is machined by the die-sinking electric discharge machine 10.

In the injection part 210, as shown in FIG. 2B, a machining fluid flow path 218 is integrally formed, which forms a flow path branched so that each injection hole 215 communicates with the machining fluid inlet hole 214. That is, a plurality of flow paths are formed inside the injection part 210, and each of the plurality of injection holes 215 is connected to one of the plurality of flow paths. In addition, a flow path for the machining fluid 310 is formed inside the support part 212. In the injection part 210, the machining fluid 310 that flows into the injection part 210 from the machining fluid inlet pipe 230 through the inside of the support part 212 branches into a plurality of paths according to the plurality of paths. The machining fluid flow path 218 is an annular cavity formed in an area surrounded by the annular outer surface 241, the annular inner surface 216, the top surface 242, and the bottom surface 217. As shown in FIG. 2B, the annular inner peripheral surface 243 is inclined with respect to the central axis 910 in the cross section of the machining fluid flow path 218. The annular inner circumferential surface 243 is the wall surface of the machining fluid flow path 218 on the back side of the annular inner surface 216. That is, the angle φ between the normal 920 and the central axis 910 is an acute angle. Here, the normal 920 is a normal to the tangent 911 and has an intersection with the central axis 910. The tangent 911 is a tangent to the annular inner circumferential surface 243 and has an intersection with the central axis 910.
As shown in FIG. 2B, the flow passage central axis of each injection hole 215 is inclined with respect to the central axis 910. The flow passage central axis of the injection hole 215a and the flow passage central axis of the injection hole 215b form different inclination angles. The flow passage central axis of the injection hole 215 indicates the direction in which the machining fluid 310 is injected from the injection hole 215. The inclination angle of each flow passage central axis is the angle between each flow passage central axis and the central axis 910. The flow passage of each injection hole 215 determines the angle at which the machining fluid 310 is injected from each injection hole 215. In FIG. 2B, the angle θ ₁ between the flow passage central axis of the injection hole 215a and the central axis of the annular portion 211 is 45 degrees, and the angle θ ₂ between the flow passage central axis of the injection hole 215b and the central axis of the annular portion 211 is 30 degrees. The angle between the flow passage central axis of injection hole 215a and the central axis of annular portion 211 is larger than the angle between the flow passage central axis of injection hole 215b and the central axis of annular portion 211. The inclination angle of each injection hole 215a of the multiple injection holes 215a does not have to be constant. The inclination angle of each injection hole 215b of the multiple injection holes 215b does not have to be constant. In addition, the normal to the annular inner surface 216 is perpendicular to the central axis 910, and the normal to the annular outer surface 241 is perpendicular to the central axis 910.
As a result, the 16 injection holes 215 provided in the injection section 210 inject the machining fluid 310 toward the periphery of the electrode 50 and the workpiece from at least two different heights along the axis of the electrode 50. Therefore, as shown in Fig. 2(a), a large flow rate of the machining fluid 310 becomes a jet and enters the machined groove. As a result, as shown in Fig. 3(b), turbulence occurs on the inner surface of the machined groove, and the machining fluid 310 circulates and convects continuously from the bottom to the top of the machined groove, so that sludge is discharged without accumulating in the machined groove.

The mounting portion 220 has end faces on which contact surfaces 222 are formed at the ends in the XY directions. The X and Y directions are shown in FIG. 3(a). A magnet 224 is also attached to the mounting portion 220. As a specific example, the magnet 224 is an on-off magnet. The mounting portion 220 is attached to the movable main shaft portion 12 by the magnet 224 in a relatively easy and detachable manner. As a specific example, the mounting portion 220 can be fixed by attaching it to the movable main shaft portion 12 with a single touch by turning on and off the on-off magnet.

The position of the ejection part 210 relative to the workpiece 500, that is, the height position in the axial direction of the electrode holder 51, can be adjusted by the adjustment holes 219. Specifically, the height of the ejection part 210 can be adjusted relatively easily by changing the mounting positions of the multiple fastening bolts 221 that pass through both any one of the multiple adjustment holes 219 in the support part 212 and any one of the multiple adjustment holes 223 in the mounting part 220.
The machining fluid ejection jig 200 is fixed to the movable main shaft portion 12 by an attachment portion 220. Therefore, even if the electrode 50 moves up and down in the vertical direction, the machining fluid ejection jig 200 does not move in conjunction with the electrode 50. Therefore, according to the above-mentioned configuration, continuous machining of a plurality of workpieces 500 can be stably performed.

In die-sinking electric discharge machining, a pulsed current is applied to the electrode 50, causing a pulsed discharge between the electrode 50 and the portion of the workpiece 500 to be machined, and an electric discharge is generated in the machining liquid 310. During this process, the portion of the workpiece 500 to be machined is locally heated to a high temperature of 6000°C to 7000°C, causing bubbles to explode in the machining liquid 310, melting the surface of the portion to be machined, and the molten portion is scattered and removed. A groove shape is then gradually formed in units of several μm depending on the discharge time, and the formed groove shape is dug down.
At this time, by using the machining fluid injection tool 200 to direct a jet of machining fluid 310 from multiple injection holes 215 onto the electrode 50 and the workpiece, it is possible to machine grooves with high-precision machining dimensions in a shorter time than conventional methods while suppressing the adhesion of sludge generated during groove formation to the groove surface.
3B illustrates a state in which the cylindrical electrode 50 is moved in units of several μm toward the bottom surface of the groove in accordance with the processing time in order to form a cylindrical groove. Not limited to this example, by making the shape of the electrode 50 annular, it is preferably possible to form an annular groove having a width of several mm with a dimensional accuracy of several μm. The shape of the electrode 50 may be polygonal or may be more complicated than a polygonal shape.

***Description of Effect of First Embodiment***
6 is a diagram for explaining the effect of this embodiment, showing a machining fluid injection device 110 according to the prior art. In the machining fluid injection device 110, the machining fluid 310 is injected using only one coolant nozzle. Therefore, since the machining fluid 310 is injected only from one direction, the sludge moves to the opposite side of the injection point of the machining fluid 310 in the machining groove. In addition, since the flow rate of the machining fluid 310 is insufficient, the sludge remaining between the workpiece and the electrode 50 cannot be discharged.
On the other hand, according to this embodiment, the multiple injection holes 215 inject the machining fluid 310 around the electrode 50 at a sufficient flow rate, so that the sludge is discharged from the machining groove. Therefore, according to this embodiment, sludge is less likely to accumulate in the machined area, so that the risk of secondary discharge can be reduced, and the risk of malfunctions occurring in the die-sinking electric discharge machine 10 can be reduced. In addition, cleaning work to prevent secondary discharge can be reduced, so that the machining time can be significantly reduced. As a specific example, the machining time per machining was 0.4 hours when the conventional technology was used, but was 0.1 hours when this embodiment was used.

Furthermore, in the machining fluid injection device 110, the positional relationship between the nozzle of the injection section and the electrode 50 changes each time the electrode holder 51 moves in at least one of the Z-axis direction, the X-axis direction, and the Y-axis direction, so that sludge cannot be stably removed by injection of the machining fluid 310.
On the other hand, according to this embodiment, the ejector 210 is attached to the movable main shaft portion 12 via the attachment portion 220. Therefore, according to this embodiment, when the movable main shaft portion 11 and the movable main shaft portion 12 move, the ejector 210 moves in conjunction with the electrode holder 51, and therefore the positional relationship between the ejector 210 and the electrode 50 does not change when the electrode holder 51 moves.

***Other embodiments***
Although the first embodiment has been described, it is possible to combine a plurality of parts of the present embodiment. Alternatively, it is possible to partially implement the present embodiment. In addition, the present embodiment may be modified in various ways as necessary, and may be implemented in any combination, either as a whole or in part.
The above-described embodiment is essentially a preferred example, and is not intended to limit the scope of the present disclosure, its applications, and uses. The described procedure may be modified as appropriate.

10 Die-sinking electric discharge machine, 11, 12 Movable spindle portion, 50 Electrode, 51 Electrode holder, 52 Lower electrode portion, 100, 110 Machining fluid injection device, 200 Machining fluid injection jig, 210 Injection portion, 211 Annular portion, 212 Support portion, 213 Mounting portion side, 214 Machining fluid inlet hole, 215, 215a, 215b Injection hole, 216 Annular inner surface, 217 Bottom surface, 218 Machining fluid flow path, 219 Adjustment hole, 220 Mounting portion, 221 Fastening bolt, 222 Contact surface, 223 Adjustment hole, 224 Magnet, 230 Machining fluid inlet pipe, 241 Annular outer surface, 242 Top surface, 243 Annular inner peripheral surface, 300 Oil supply device, 301 In-equipment tank, 302 Filter, 305 Discharge hole, 306 Suction hole, 310 machining fluid, 400 piping hose, 500 workpiece, 600 fluid receiver, 650 hose, 910 central axis, 911 tangent, 920 normal.

Claims (9)

A machining fluid injection device for injecting machining fluid in a die-sinking electric discharge machine,
a machining fluid injection device including a plurality of injection holes formed radially around an electrode of the die-sinking electric discharge machine for injecting machining fluid toward the electrode, the machining fluid injection device including an injection part that moves in conjunction with a movable main spindle part of the die-sinking electric discharge machine,
The ejection portion includes a ring-shaped portion surrounding the electrode,
the plurality of injection holes includes a plurality of upper injection holes and a plurality of lower injection holes,
the upper injection holes are formed radially around the electrode on an annular inner surface of the annular portion facing the electrode,
The machining fluid injection device has a bottom surface in the vertical direction of the annular portion, the plurality of lower injection holes being formed radially around the electrode . The machining fluid injection device according to claim 1, wherein the direction in which each of the multiple injection holes injects machining fluid is inclined with respect to the central axis of the electrode. an angle between a direction in which each of the plurality of upper injection holes injects machining fluid and a central axis of the annular portion is equal to or greater than 40 degrees and equal to or less than 60 degrees;
3. The machining fluid injection device according to claim 1, wherein an angle between a direction in which the machining fluid is injected from each of the plurality of lower injection holes and a central axis of the annular portion is 20 degrees or more and 40 degrees or less. The number of the upper injection holes is eight,
The upper injection holes are formed at equal intervals on the annular inner surface,
The number of the lower injection holes is eight,
The machining fluid ejection device according to claim 1 , wherein the plurality of lower ejection holes are formed at equal intervals in the bottom surface. The ejection portion includes a support portion that supports the annular portion,
The machining fluid injection device further comprises:
a mounting portion to which the support portion is fastened,
The machining fluid ejection device according to claim 1 , wherein the attachment portion is detachably attached to a movable main spindle portion of the die-sinking electric discharge machine. The machining fluid ejection device according to claim 5 , wherein the attachment portion is detachably attached to the movable main shaft portion by magnetic force. 7. The machining fluid ejection device according to claim 5 , wherein the position of the annular portion in the vertical direction can be changed by changing the position at which the support portion and the attachment portion are fastened. A plurality of flow paths are formed inside the ejection portion,
Each of the plurality of injection holes is connected to any one of the plurality of flow paths,
A flow path for a machining fluid is formed inside the support portion,
A machining fluid inlet pipe through which a machining fluid flows is detachably attached to the support portion,
The machining fluid injection device according to any one of claims 5 to 7 , wherein inside the injection section, the machining fluid flowing from the machining fluid inlet pipe through the inside of the support section into the injection section branches into multiple paths according to the multiple flow paths. A machining fluid injection method for injecting machining fluid from a plurality of injection holes formed in an injection section of a die-sinking electric discharge machine toward an electrode of the die-sinking electric discharge machine, comprising:
The plurality of injection holes are formed radially around the electrode,
The injection unit moves in conjunction with a movable spindle unit of the die-sinking electric discharge machine,
The ejection portion includes a ring-shaped portion surrounding the electrode,
the plurality of injection holes includes a plurality of upper injection holes and a plurality of lower injection holes,
the upper injection holes are formed radially around the electrode on an annular inner surface of the annular portion facing the electrode,
The machining fluid jetting method, wherein the plurality of lower jet holes are formed radially around the electrode on a bottom surface in a vertical direction of the annular portion.

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