JP2013158897A - Cutting processing machine and cutting tool recovery processing method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting processing machine capable of effectively performing a recovery process for an abraded tip of a blade of a cutting tool with the cutting tool mounted on a main shaft and further provide a cutting tool recovery processing method using the cutting processing machine.SOLUTION: A cutting tool recovery processing method performed by a cutting processing machine 11, includes steps of (1) stopping a cutting process of a work 61 by a drill 3, (2) making a tool electrode 50 face the tip of a blade of the drill 3 with the drill 3 held in a main shaft 21, and (3) applying a voltage to the tool electrode 50 through an electrolytic processing power supply with a processing liquid 4 supplied, by a processing liquid supply means 24, between the tip of the blade of the drill 3 and the tool electrode 50 and then performing the recovery process for the tip of the blade of the drill 3 by electrolytic processing. As a result, eliminated is the need for moving a grinding stone along a shape of the tip of the blade and for using a plurality of grinding stones, and therefore a more effective recovery process becomes possible as compared to the conventional art of grinding a cutting tool by a rotating grinding stone.

Description

  The present invention relates to a cutting machine that cuts a workpiece with a cutting tool, and a cutting tool regeneration processing method using the same.

Conventionally, when a cutting tool used in a cutting machine wears out, the operation of the cutting machine is temporarily stopped, the operator removes the cutting tool from the spindle, and the worn cutting edge is polished by a separately provided blade grinder. Once again, it was attached to the spindle of the cutting machine. For this reason, there has been a problem that it takes time for an operator to attach and detach the cutting tool and the operation of the cutting machine stops during the polishing operation.
Further, in the method in which the cutting machine is provided with tool holding means and a plurality of cutting tools are set in the tool holding means in advance, a plurality of cutting tools and tool holding means are required, which increases the equipment cost.

  Therefore, Patent Document 1 discloses a lathe with a bite forming machine capable of polishing a bite by rotating the grindstone while providing a grindstone on the head stock side in the processing machine and attaching the bite to the bite holder. .

JP-A-5-162005

  The lathe with a bite forming machine described in Patent Document 1 is considered to be effective for a bite having a relatively simple cutting edge shape. However, when applying to a drill or the like having a three-dimensional cutting edge shape, it is necessary to move the grindstone along the shape of the cutting edge or to use a plurality of grindstones. Further, since the machining is performed while measuring the size of the cutting tool against the wear of the grindstone and correcting the feed amount of the grindstone, there is a problem that it takes a long machining time and is not efficient.

  The present invention was created in view of the above points, and an object of the present invention is to use a cutting machine capable of efficiently reworking a worn blade edge while the cutting tool is attached to the main shaft, and to use the same. It is to provide a cutting tool regeneration processing method.

The cutting machine according to the present invention includes a cutting tool for cutting a workpiece, a spindle, a fixed base, a relative movement unit, a tool electrode, a processing liquid supply unit, and an electrolytic processing power source.
The main shaft holds one of the cutting tool and the workpiece so as to be rotatable about the axis.
The fixed base is fixed and held so that the other of the workpiece and the cutting tool faces the main shaft.
The relative moving means moves the main shaft and the fixed base so as to approach or separate from each other relatively.
The tool electrode is formed in a shape corresponding to the cutting edge shape of the cutting tool. When the cutting tool stops cutting the workpiece, the tool electrode faces the cutting edge of the cutting tool while the cutting tool is held on the spindle or the fixed base, and the cutting edge of the cutting tool can be regenerated by electrolysis.
When the tool electrode moves to a position where the cutting tool can be reprocessed, the machining fluid supply means supplies the machining fluid in which the electrolyte containing the surfactant is mixed into the machining oil between the cutting edge of the cutting tool and the tool electrode. .
The electrolytic processing power source applies a voltage to the tool electrode.

  As described above, the cutting machine according to the present invention reprocesses the worn edge of the cutting tool by electrolysis using the tool electrode. Therefore, it is not necessary to move the grindstone along the shape of the cutting edge or to use a plurality of grindstones, unlike a lathe with a conventional bite forming machine. Further, it is not necessary to measure the size of the cutting tool against the wear of the grindstone and correct the feed amount of the grindstone. Therefore, the worn cutting edge can be efficiently reprocessed with the cutting tool attached to the main shaft.

By the way, for a throw-away tip having a straight cutting edge or a general cutting tool, there may be a case where reworking is possible only by bringing the tool electrode close to the cutting edge from one direction. However, in the case of a drill or an end mill, the cutting edge is formed by twisting three-dimensionally, so that it is necessary to set the tool electrode at a position where it is pushed into the hollow portion. Therefore, it is difficult to perform high-quality remanufacturing by simply bringing one tool electrode close to the cutting edge.
Therefore, in this case, the tool electrode is preferably composed of a plurality of divided electrodes. When the cutting tool cuts the workpiece, the plurality of divided electrodes are moved to a retreat position that avoids interference with the cutting tool and the workpiece, and when the cutting tool stops cutting the workpiece, the plurality of divided electrodes are It is preferable to provide an electrode moving means for moving to a concentration position facing the cutting edge of the cutting tool.

Further, the cutting machine is divided into a group such as a drilling machine, a milling machine, and a machining center where a rotating tool cuts a fixed work, and a group such as a lathe where a non-rotating tool cuts a rotating work. In particular, when a rotary tool such as a drill or end mill having a three-dimensional cutting edge is regenerated, the position when the rotary tool stops needs to correspond to the set position of the tool electrode.
Therefore, in this case, the cutting machine preferably includes stop position control means for controlling braking of the main shaft so that the cutting tool stops at a predetermined rotational position when the rotation of the main shaft is stopped.

The present invention further provides a cutting tool regeneration processing method using the above cutting machine.
In this cutting tool regeneration processing method, (1) the step of cutting the workpiece by the cutting tool is stopped, and (2) the tool electrode faces the cutting edge of the cutting tool while the cutting tool is held on the spindle or the fixed base. (3) a step in which the machining power supply means applies a voltage to the tool electrode while the machining fluid supply means supplies the machining fluid between the cutting edge of the cutting tool and the tool electrode, and regenerates the cutting edge of the cutting tool by electrolysis ,including.
Thereby, there exists an effect similar to said cutting machine.

It is a schematic block diagram at the time of non-operation of the cutting machine by 1st Embodiment of this invention. It is a schematic block diagram at the time of the workpiece cutting by the drill of the cutting machine by 1st Embodiment of this invention. It is a schematic block diagram at the time of the drill reproduction | regeneration processing of the cutting machine by 1st Embodiment of this invention. It is a schematic diagram of the tool electrode of the cutting machine by 1st Embodiment of this invention. It is a schematic diagram of the drill reprocessed with the cutting machine by 1st Embodiment of this invention. It is a characteristic view which shows the relationship between the electrolyte ratio of the processing oil used for the cutting machine by 1st Embodiment of this invention, and electrical conductivity. It is a schematic block diagram of the cutting machine by 2nd Embodiment of this invention. It is a schematic diagram of the tool electrode of the cutting machine by 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
The cutting machine of 1st Embodiment of this invention is demonstrated with reference to FIGS.
As shown in FIGS. 1 to 3, the cutting machine 11 according to the first embodiment is a type of “a rotating cutting tool, that is, a rotating tool cuts a fixed workpiece” such as a drilling machine, a milling machine, and a vertical machining center. It is based on a cutting machine. The cutting machine 11 includes a main shaft 21 and a main shaft driving means 22 at the upper part of the machine main body 20, and a work table 26 at the lower part of the machine main body 20. In addition, an electrode base 23 is provided at an intermediate portion in the height direction of the machine body 20.

  The main shaft 21 is a spindle shaft that is rotated by a motor. A rotary tool such as a drill or an end mill is rotatably held around the shaft center at a chuck portion such as a collet chuck provided at the lower portion of the main shaft 21. In the following description of the present embodiment, it is assumed that the rotary tool is the drill 3.

The main shaft driving means 22 corresponds to the “relative movement means” described in the claims, and moves the main shaft 21 up and down. In addition, a machining fluid supply unit 24 for supplying the machining fluid 4 to the cutting edge of the drill 3 is attached to the spindle driving unit 22 so as to be able to move up and down along with the spindle 21.
The work base 26 corresponds to a “fixed base” recited in the claims, and holds the work 61 fixed so as to face the main shaft 21. As the main shaft 21 is moved up and down by the main shaft driving means 22, the main shaft 21 and the work table 26 are relatively approached or separated from each other.

  A tool electrode 50 is attached to the electrode table 25. In the present embodiment, the tool electrode 50 includes three divided electrodes 51, 52 and 53. The three divided electrodes 51, 52, 53 are moved between the retracted position shown in FIGS. 1 and 2 and the concentrated position shown in FIG. 3 by the electrode moving means 25. At the retracted position, the divided electrodes 51, 52, 53 are prevented from interfering with the drill 3 and the work 61.

Specifically, as shown in FIG. 4, the divided electrode 51 and the divided electrode 52 are disposed inward on opposite sides of the drill 3 in the horizontal direction. The divided electrode 53 is arranged upward on the lower side in the axial direction with respect to the drill 3.
Further, the divided electrodes 51 and 52 have flank electrode surfaces 511 and 521 facing a flank 32 of the drill 3 to be described later. The divided electrode 53 has a thinning electrode surface 531 facing a thinning 33 of the drill 3 to be described later. The flank electrode surfaces 511 and 521 and the thinning electrode surface 531 are formed in a three-dimensional shape.

  Further, the divided electrodes 51, 52, 53 are connected to the negative electrode of the electrolytic processing power supply 45, and the drill 3 is connected to the positive electrode of the electrolytic processing power supply 45. Thereby, when the machining liquid 4 is supplied from the machining liquid supply means 24 between the cutting edge of the drill 3 and the divided electrodes 51, 52, 53, the electrolyte in the machining liquid 4 is ionized into positive ions and negative ions. .

  In addition, the rotation position of the main shaft 21 that holds the drill 3 is determined by the stop position control means 29 when stopped. That is, the stop position control means 29 controls the braking of the main shaft 21 motor so that the drill 3 always stops at a constant rotational position when the rotation of the main shaft 21 stops. Thereby, the divided electrodes 51, 52, 53 always face the same part of the drill 3.

  As shown in FIG. 5, the drill 3 is formed by twisting two blades around the central axis Z, and a cutting blade 31 is provided at the end of the flank 32. A thinning 33 is provided along the central axis Z. The material of the drill 3 is generally high speed or carbide. In the present embodiment, an insulating coating is applied to portions other than the flank 32 and the thinning 33.

The processing liquid 4 is a liquid in which an electrolyte containing a surfactant is mixed in processing oil at a predetermined ratio. As the electrolyte, for example, sodium nitrate can be used. Further, the processing oil is oil that is generally used for cutting of steel or the like. By uniformly mixing the non-conductive processing oil and the aqueous electrolyte solution with the surfactant, a processing liquid capable of electrolytic processing can be obtained.
Here, as shown in FIG. 6, the electrical conductivity of the working fluid increases rapidly when the electrolyte ratio exceeds α, in other words, when the oil ratio falls below (1-α). The phenomenon is that "if the oil ratio is above a certain threshold, the passage of ions is blocked by the oil polymer, but if the oil ratio is less than that threshold, ions can freely pass through the gaps in the oil polymer." Explained by infiltration theory.
Therefore, what is necessary is just to set the ratio of the electrolyte of the process liquid 4 so that it may become larger than (alpha).

Next, the cutting tool reproduction | regeneration processing method using the cutting machine 11 by the above structure is demonstrated.
At the initial setting stage, the drill 3 is attached to the chuck portion of the main shaft 21. Subsequently, fine adjustment is performed so that the rotational position of the drill 3 when the main shaft 21 is stopped matches the set position of the tool electrode 50, and the rotational position of the main shaft 21 at this time is stored in the stop position control means 29. Further, the work 61 made of steel or the like is fixed to a receiving jig or the like on the work base 26.
The divided electrodes 51, 52, 53 of the tool electrode 50 are arranged at the retracted position shown in FIG. 1 by the electrode moving means 25.

  When the operation of the cutting machine 11 is started, the main shaft 21 is lowered to the cutting position shown in FIG. Then, the cutting edge 31 of the drill 3 comes into contact with the workpiece 61, and drilling of the workpiece 61 is started. At this time, the machining fluid supply means 24 supplies the machining fluid 4 to the cutting edge of the drill 3 for use as machining oil. The cut chips are guided by the groove of the drill 3 and discharged.

In the present embodiment, the spindle driving means 22 also has a feeding function of the spindle 21 and further lowers the spindle 21 at a constant feeding speed to make a hole in the work 61 to a set depth.
When the machining of one workpiece 61 is completed, the spindle driving means 22 raises the spindle 21 to a height at which the drill 3 is separated from the workpiece 61. Then, the processed workpiece 61 is removed from the receiving jig by an operator or an automatic conveyance device (not shown), and the next workpiece 61 is set.

In this way, when the machining of the predetermined number of workpieces 61 is completed, or at any time according to the judgment of the operator, the worn edge of the drill 3 is regenerated. This regeneration processing method includes the following steps (1) to (3).
(1) a step of stopping the cutting of the workpiece 61 by the drill 3;
(2) The stage in which the tool electrode 50 faces the cutting edge of the drill 3 while the drill 3 is held by the main shaft 21;
(3) The machining power supply 45 applies a voltage to the tool electrode 50 while the machining fluid supply means 24 supplies the machining fluid 4 between the cutting edge of the drill 3 and the tool electrode 50, and the cutting edge of the drill 3 is regenerated by electrolysis. The stage to process.

In the stage (1), when the rotation of the main shaft 21 is stopped, the stop position control means 29 controls the braking of the main shaft 21 motor so that the drill 3 stops at the rotational position detected in the initial setting stage. .
In the stage (2), the electrode moving means 25 moves the divided electrodes 51, 52, 53 from the retracted position shown in FIGS. 1 and 2 to the concentrated position shown in FIG. Specifically, as shown in FIG. 4, the divided electrodes 51 and 52 move in the horizontal direction so that the flank electrode surfaces 511 and 521 approach the flank 32 of the drill 3. Further, the divided electrode 53 moves in the vertical direction so that the thinning electrode surface 531 approaches the thinning 33 of the drill 3.

  In the stage of (3) above, the cutting edge of the drill 3 is reprocessed by electrolyzing the electrolyte in the machining fluid 4 by applying a voltage. In the present embodiment, the flank 32 and the thinning 33 that are not provided with the insulating coating are processed parts. As a result, the tip shape of the tool electrode 50 is transferred to the workpiece of the drill 3.

  Specifically, the conditions of the regenerating process are a distance between the tool electrode 50 and the cutting edge of the drill 3 of several micrometers to several tens of micrometers, the voltage of the electrolytic processing power supply 45 is several volts to several tens volts, and the energization time is several tens of micrometers. It can be nanoseconds to several tens of milliseconds. These machining conditions are preferably adjusted depending on the cutting load of the workpiece 61, the frequency of execution of the reworking process, whether the material of the drill 3 is high speed or carbide.

  For example, if the regenerating process is executed every time one workpiece 61 is processed, the amount of electrolysis per time can be minimized and the variation in the wear state of the drill 3 can be minimized. Further, if the regenerating process is executed during the time for exchanging the work 61 of the work table 26, the cycle time does not increase. Therefore, it is effective for stabilizing the quality especially in mass production by automatic production.

  As described above, according to the cutting tool regenerating method using the cutting machine 11 of the present embodiment, the worn cutting edge can be reprocessed while the drill 3 is held on the main shaft 21. There is no need to remove the drill 3 from the main shaft 21 for polishing. Therefore, the number of man-hours for the operator for detachment becomes unnecessary, and the operation of the cutting machine need not be stopped. Moreover, it is not necessary to set a plurality of cutting tools in the tool holding means in advance.

  In addition, since the regenerating process is performed by electrolysis using the tool electrode 50, it is not necessary to move the grindstone along the shape of the cutting edge or to use a plurality of grindstones, unlike a lathe with a cutting tool of the prior art. Further, it is not necessary to measure the size of the cutting tool against the wear of the grindstone and correct the feed amount of the grindstone. Therefore, more efficient regeneration processing becomes possible.

Furthermore, by configuring the tool electrode 50 from a plurality of divided electrodes 51, 52, 53, it is possible to arrange the three-dimensional cutting tool so that, for example, the electrode protrudes into a hollow portion. is there. Therefore, it is possible to realize highly accurate remanufacturing with respect to a cutting tool that cannot be processed by grinding with a conventional grindstone.
Moreover, since the stop position control means 29 controls the braking of the motor for the main shaft 21 so that the drill 3 always stops at a fixed rotational position, the application to the rotary tool becomes easy.

In addition, the working fluid 4 serves both as a working oil during cutting and as a conductive electrolyte during electrolytic regeneration. This is achieved by uniformly mixing the processing oil and the aqueous electrolyte solution with a surfactant. Thereby, since it is not necessary to supply processing oil and an electrolyte separately, the structure of a machine can be simplified and it is effective also in reuse of a waste liquid.
Further, in this embodiment, the drill 3 that is a cutting tool is not subjected to electrolytic processing in the insulating coating other than the flank 32 and the thinning 33, so that the cutting edge 31 can be made sharper by electrolytic regeneration processing. it can.

(Second Embodiment)
Next, the cutting machine of 2nd Embodiment of this invention is demonstrated with reference to FIG. 7, FIG.
As shown in FIG. 7, the cutting machine 12 according to the second embodiment is based on a lathe “a non-rotating tool cuts a rotating workpiece”. The cutting machine 12 includes a headstock 72 on the left side of the paper on the bed 70 and a tool rest 76 on the right side of the paper.
The headstock 72 is provided with a main shaft 71 that rotates about a horizontal axis. A cylindrical workpiece 62 is normally chucked on the main shaft 71.

  The tool post 76 is installed on the feed unit 77 and is movable in the xy axis, that is, in the left-right direction and the depth direction on the paper surface. The feed unit 77 is installed on a height adjustment unit 78 that adjusts the height in the vertical direction of the z axis, that is, the paper surface. A holder 80 holding a tip cutter 8 as a “cutting tool” at the tip is fixed to the tool rest 76. In the second embodiment, the feeding portion 77 corresponds to “relative movement means” described in the claims, and the spindle 71 and the tool rest 76 are relatively approached or separated by operation of the feeding portion 77.

Further, the cutting machine 12 includes an electrode table 73 between the main spindle 71 in the longitudinal direction of the bed 70 and the tool rest 76. A tool electrode 55 is attached to the electrode base 73 at a position where it does not interfere with the tip cutter 8, the holder 80, the work 62, and the like during cutting.
A machining fluid supply means 74 for supplying the machining fluid 4 to the cutting edge of the tip cutter 8 is provided above the tool rest 76.

As shown in FIG. 8, the cutting tool 81 has a cutting edge 81 formed on the ridge line between the rake face 83 on the upper surface and the flank face 82 on the side surface. In this embodiment, the rake face 83 is provided with an insulating coating, and the flank face 82 becomes a part to be processed in electrolytic regeneration processing.
When cutting the workpiece 62, the tool rest 76 is advanced to the left in the drawing, and the cutting blade 81 is brought into contact with the side surface or end surface of the rotating workpiece 62 while supplying the machining fluid 4 to the cutting edge of the tip cutter 8. To cut.

The tool electrode 55 has a flank electrode surface 551 that faces the flank 82 of the cutting tool 8. The flank electrode surface 551 is formed by a surface cut into a V shape when viewed from above.
The tool electrode 55 is connected to the negative electrode of the electrolytic processing power supply 45, and the tip blade 8 is connected to the positive electrode of the electrolytic processing power supply 45. Here, the electrolytic processing power supply 45 and the processing liquid 4 are substantially the same as those of the first embodiment and operate in the same manner. Therefore, when the machining fluid 4 is supplied from the machining fluid supply means 74 between the cutting edge of the tip cutter 8 and the tool electrode 55, the electrolyte in the machining fluid 4 is ionized into positive ions and negative ions, and the flank 82. Is electrolytically regenerated.

In the second embodiment, the worn cutting edge can be reprocessed while the tip cutter 8 is held in the holder 80 on the tool rest 76.
Further, unlike the first embodiment, the tip cutter 8 has a flank 82 serving as a part to be processed and has a simple shape, and therefore can be reprocessed using the non-divided tool electrode 55. Furthermore, since the tip cutter 8 is a non-rotating tool, the stop position control means as in the first embodiment is not required.

(Other embodiments)
(A) In the first embodiment, the number of the plurality of divided electrodes is not limited to three. For example, a tool electrode for a four-blade end mill may be composed of four divided electrodes, four in the horizontal direction and one for thinning.
The moving direction of the plurality of divided electrodes by the electrode moving means is not limited to the horizontal direction or the vertical direction, but may be an oblique direction. Further, not only sliding movement but also rotational movement may be involved.
(A) In the first embodiment, the feeding operation during the cutting process may be performed by raising the work table 26.

(C) In the lathe-type cutting machine of the second embodiment, a tool electrode made up of a plurality of divided electrodes may be used, for example, when a drill held in a pressing cup is regenerated.
(D) The cutting tool regeneration processing method of the present invention can be applied to, for example, a milling cutter or a side cutter to which a plurality of chip cutters are attached. In general, the unit price of the throw-away tip is low, but particularly when a plurality of throw-away chips are used, the cost reduction effect is increased by using the throw-away tip for a long period of time by reprocessing.

(E) When a stepped cutter having a large-diameter cutting part and a small-diameter cutting part is polished by rotating a grindstone as in the prior art, it is relatively peripheral to a large-diameter part having a relatively high peripheral speed. The amount of polishing varies between the small-diameter portion having a small speed. On the other hand, in the electrolytic regeneration processing method of the present invention, uniform regeneration processing can be performed regardless of the difference in radius.
As mentioned above, this invention is not limited to such embodiment, In the range which does not deviate from the meaning of invention, it can implement with a various form.

11, 12 ... Cutting machine,
21, 71 ... main shaft,
22 ... Spindle drive means (relative movement means), 77 ... Feeding part (relative movement means),
24, 74 ... working fluid supply means,
26: Work table (fixed table) 76: Tool table (fixed table)
3 ... Drill (cutting tool), 8 ... Chip cutter (cutting tool),
4 ... machining fluid,
45 ... Electrolytic machining power supply,
50, 55 ... tool electrodes,
61, 62 ... Workpiece.

Claims (4)

Cutting tools (3, 8) for cutting the workpieces (61, 62);
Spindles (21, 71) for holding one of the cutting tool or the workpiece rotatably about an axis;
A fixing base (26, 76) for fixing and holding the other of the workpiece or the cutting tool so as to face the main shaft;
Relative moving means (22, 77) for moving the main shaft and the fixed base so as to be relatively close to or away from each other;
The cutting tool is formed in a shape corresponding to the cutting edge shape of the cutting tool, and when the cutting tool stops cutting the workpiece, the cutting tool is held on the spindle or the fixed base and the cutting edge of the cutting tool is Opposing tool electrodes (50, 55) capable of regenerating the cutting edge of the cutting tool by electrolysis,
When the tool electrode moves to a position where the cutting tool can be reprocessed, a working fluid (4) in which an electrolyte containing a surfactant is mixed in the working oil is supplied between the cutting edge of the cutting tool and the tool electrode. Machining fluid supply means (24, 74) to perform,
An electrolytic power source (45) for applying a voltage to the tool electrode;
A cutting machine (11, 12) comprising: The tool electrode (50) is composed of a plurality of divided electrodes (51, 52, 53),
When the cutting tool cuts the workpiece, the plurality of divided electrodes are moved to a retreat position that avoids interference with the cutting tool and the workpiece, and when the cutting tool stops cutting the workpiece, The cutting machine (11) according to claim 1, further comprising electrode moving means (25) for moving the plurality of divided electrodes to a concentrated position facing a cutting edge of the cutting tool. The cutting tool is a rotary tool that rotates while being held by the spindle.
The stop position control means (29) for controlling braking of the main shaft so as to stop the cutting tool at a fixed rotational position when the rotation of the main shaft is stopped is provided. Cutting machine. It is a cutting tool reproduction | regeneration processing method using the cutting machine as described in any one of Claims 1-3,
Stopping the cutting of the workpiece by the cutting tool;
The tool electrode facing the cutting edge of the cutting tool while the cutting tool is held by the main shaft or the fixed base;
While the machining fluid supply means supplies the machining fluid between the cutting edge of the cutting tool and the tool electrode, the electrolytic processing power supply applies a voltage to the tool electrode, and the cutting edge of the cutting tool is regenerated by electrolysis. And the stage of
The cutting tool reproduction | regeneration processing method characterized by including.

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