JPH02145217A - Electricity discharge machine for turbine rotor - Google Patents

Abstract

PURPOSE:To arrange so that two kinds of machining may be conducted against a turbine rotor simultaneously at one step, by providing at one electricity discharge machine two independent machining heads, the 1st head and 2nd head, and controlling the dividing rotation of a rotary table with inclination and the movements of the 1st machining head and the 2nd machining head, by means of an NC device. CONSTITUTION:The respective movements of the 1st and 2nd machining heads independently provided at one electricity discharge machine 8, and the dividing rotation of a rotary table with inclination 12, are controlled by means of an NC device 35. As a result, two kinds of machining can be conducted against a turbine rotor simultaneously at one step. Also, the exhaustion of machining electrodes 22, 23 during electricity discharge machining is inspected by means of this NC device 35, and these exhausted machining electrodes 22, 23 are exchanged with new ones by means of electrode exchangers 26, 27 at an appropriate exchange time. As a result, the machining cycle time of the turbine rotor can be shortened, and at the same time, a high precision electricity discharge machining can be done by using electrodes 22, 23 which are free of exhaustion at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Utilization Public Expenses> The present invention relates to an electric discharge machining apparatus used for machining a turbine rotor.

<Prior Art> A turbine is a machine that generates mechanical rotational power from a flow of fluid. Rotational power is generated through a turbine rotor that has a large number of blades (rotary vanes) provided on the outer circumference of a disk.

FIG. 3 shows a perspective view of a turbine rotor used in small engines and the like. The turbine rotor 1 is composed of an axial rotor 4 and a disk 2 formed at an end of the rotor 4, and a large number of blades 3 are integrally formed on the outer periphery of the disk 2.

FIG. 4 shows a diagram of the finishing state of the blade 3 by conventional electrical discharge machining. When the number of blades 3 of the turbine quadrature is small, rough machining to form a profile (airfoil shape) is performed by precision casting. After the blade 3 is formed on the outer periphery of the disk 2 by precision casting, the profile of the blade 3 is finished by electrical discharge machining. Finishing of the blade 3 by electrical discharge machining involves rotating the photoelectrode 5 in the V direction (
Profile formation is performed by moving (revolving) the outer periphery of the blade 3 two-dimensionally in the W direction while rotating (rotating).

When the turbine rotor 1 has a large number of 30 blades, precision casting of the blades 3 is technically impossible. If precision casting is not possible, complete machining is normally performed, but since the material forming the blade 3 and disk 2 is a difficult-to-cut material, milling is also impossible, and the profile must be formed by electrical discharge machining. . 58 shows a rough machining situation diagram of the blade 3 by electric discharge machining, and FIG. 6 shows a finishing machining situation diagram of the blade 3. The direction of arrow a in FIG. 5 indicates a direction from the circumference of the disk toward the inside of the circumference.

Rough machining of the blade 3 by electrical discharge machining is performed using a full-form rough machining electrode 22. By moving the rough machining electrode 22 from the outer periphery of the disk 2 in the direction a, the rough machining allowance 7 is removed and the approximate profile of the blade 3 is formed. The blade 3 that has undergone rough processing is subjected to semi-finishing and final finishing. For semi-finishing and final finishing, use the blade 3 mentioned above.
Similar to the finishing process performed when the number of sheets is small, the outer periphery of the blade 3 is moved two-dimensionally (revolution) in the W direction while the photoelectrode 5 is rotated (rotated) in the V direction to remove the finishing allowance 38 and form a profile. is completed.

<Problem to be solved by the invention> However, when finishing the profile shape using a photoelectrode, if the photoelectrode wears out and becomes thinner during electrical discharge machining, the profile shape becomes unstable and uneven blade thickness occurs. . If the thickness of the blades is uneven, it will have a negative effect on the balance accuracy and high efficiency when the turbine rotor rotates. In order to eliminate blade misalignment, it is necessary to replace the photoelectrode frequently, but if the photoelectrode is replaced frequently, the processing cycle time will be lengthened due to a decrease in work efficiency, making it difficult to quickly develop high-efficiency turbines. This was a major obstacle.

The present invention has been made to solve the above-mentioned drawbacks.
An object of the present invention is to provide a turbine rotor electric discharge machining device that can carry out rough machining and finishing machining of a turbine rotor profile with high precision and in a short time, thereby ensuring high quality of the turbine rotor and shortening the machining cycle time.

Means for Solving the Eight Problems> A machining liquid tank provided in a bed, a tilted rotary table provided in the machining liquid tank for holding a turbine rotor and rotating the turbine rotor for cutting out, a first machining head and a second machining head that are respectively provided on a bed with a tilted rotary table in between and supported so as to be positionable and movable with respect to the tilted rotary table; electrode hands each provided at the side end of the tilted rotary table and gripping a processing electrode for processing the blades of the turbine rotor; and electrode hands each provided at each of the first processing head and the second processing head and holding a plurality of processing electrodes for processing the blades of the turbine rotor. an electrode exchange device comprising: a rack in which the processing electrodes are stored; and an exchange means for exchanging the processing electrodes between the rack and the electrode hand; Positioning movement of the processing head and the second processing head and the processing f4 by the electrode exchange device
It is characterized by comprising an NC device for controlling pole exchange.

Operation> The first machining head moves on the turbine rotor attached to the tilted rotary table, and machining is performed using the machining electrode held by the electrode hand. When the first machining head completes machining, the tilted rotary table indexes and rotates, and the next machining part of the turbine rotor reaches the position of the first machining head, and the first machining head performs the next machining.

will be held. When the first machining end portion by the first machining head is rotated to the position of the second machining head, the first machining head and the second machining head perform simultaneous machining. Simultaneous machining is performed until the first machining finished part by the second machining head returns to the first machining head. When the first machining finished part by the second machining head returns to the first machining head, machining by the first machining head ends and the first machining head stops. Single machining with the second machining head and index rotation with the tilted rotary table are
The first machining finished part by the second machining head passes through the first machining head and reaches the second machining head.After machining the previous machining part, the individual machining by the second machining head is completed, and the second machining head stops. do. Wearing of the machining electrode during electrical discharge machining is detected in advance, and the electrode is replaced at an appropriate time using an electrode replacement device. The movement of the first processing head and the second processing head, the indexing rotation of the inclined rotary table, and the exchange of the processing electrode are controlled by the NC device.

Embodiment Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings. FIG. 1 is a perspective view of an electric discharge machining apparatus which is an embodiment of the present invention, and FIG. 2 is a partially enlarged view of the electric discharge machining apparatus which is an embodiment of the present invention. The workpiece is a turbine rotor shown in FIG. 3, and the same members as in FIG. 3 are given the same reference numerals and redundant explanations will be omitted.

A processing table 10 is provided above the bed 9. A machining liquid tank 11 is provided in the center of the machining table 10, and the machining liquid tank 11 has an open top and a door 15 that can be opened and closed in the front. Machining fluid is supplied to the machining fluid tank 11 by a machining fluid supply device (not shown in the drawing), and the supplied machining fluid is discharged from the machining fluid tank 11. A tilted rotary table 12 is provided in the center of the machining liquid tank 11 to which a turbine rotor 1, which is a workpiece, is attached.The tilted rotary table 12 rotates the turbine rotor 1 to determine the number of blades 3. Rotation is now possible.

On the processing table 10, a first support 13 and a second support 14 are provided on both sides of the processing liquid tank 11. A first processing head main body 18 and a second processing head main body 19 are attached to the upper part of the first support stand 13 and the upper part of the second support stand 14. The first processing head main body 18 and the second processing head main body are provided with a first head 36 and a second head 37 at the end on the processing liquid tank 11 side, and further, the first head 36 and the second head 37 are provided with A first electrode hand 20 and a second electrode hand 21 are provided at the tip. The first electrode hand 20 and the second electrode hand 21 can detachably hold a rough machining electrode 22 which is a machining electrode and a finishing machining electrode 23 which is a machining electrode. The first electrode hand 20 and the second electrode hand 21 are
The rough machining electrode AII 22 and the finishing machining electrode 23 are held and positioned in the machining liquid tank 11.

The first processing head body 18 and the second processing head body 19 are provided with a first electrode exchange device 26 which is an electrode exchange device and a second electrode exchange device 27 which is an electrode exchange device 1. 26 and the second electrode exchange device 27 are provided with a first electrode rack 31 and a second electrode rack 32. The first electrode rack 31 and the second electrode rack 32 are provided with a large number of rough machining electrodes 22 and finishing machining electrodes 23 on their outer peripheries in a detachable manner. An electrode exchange arm that is an exchange means for exchanging the rough machining electrode 22 and the finishing machining electrode 23 between the first electrode hand 20 and the first electrode rack 31 and between the second electrode hand 21 and the second electrode rack 32 are provided in the first electrode exchange device 26 and the second electrode exchange device 27, respectively. Therefore, the first processing head main body 18, the first head 36, the first electrode hand 20, and the first electrode exchange device 2
6 constitutes a first processing head 16, which includes a second processing head main body 19, a second head 37, and a first electrode hand 20.
Then, the rad 17 for the second processing is configured by the second electrode exchange device 27.

The direction in which the first processing head 16 and the second processing head 17 move toward and away from the inclined rotary table 12 is the Z axis.
The vertical direction perpendicular to the axis is the Y axis, and the horizontal direction perpendicular to the Z axis is the X axis. The first processing head main body 18 and the second processing head main body 19 are attached to the first support stand 13 and the second support stand 14 so as to be movable in the x, y, and z axis directions, and are positionable and movable with respect to the tilted rotary table 12. It is.

The first head 36 and the second head 37 are rotatably attached around the first support shaft 24 and the second support shaft 25 that extend parallel to the x-axis.

The inclination angle of the rough machining electrode 22 and the finishing machining electrode 23 in the X-axis direction with respect to the turbine rotor 1 attached to the tilted rotary table 12.

After the position 1i1111 in the Y-axis direction, profile formation of the turbine rotor 1 is performed completely automatically by electric discharge machining.

The first machining head moves in the x, y, and z axis directions while being controlled, and performs electrical discharge machining while bringing the rough machining electrode 22 into contact with the disk 2 of the turbine rotor 1 mounted on the tilted rotary table 12. As the first machining head main body 18 moves, the rough machining electrode 22 moves in a direction from the circumference of the disk 2 toward the inner circumference, and in a direction away from the circumference of the disk 2 from the disk 2. controlled. After the rough machining of the blade 3 is performed, the rough machining electrode 22 separates from the disk 2 and waits at the machining origin until the next rough machining. The tilted rotary table 12 rotates the turbine rotor 1 at an angle of A degree (
360 degrees/number of blades) index rotation. When the inclined rotary table rotates by A degree, the rough machining electric WA 22 that was waiting at the machining origin moves from the circumference of the disk 2 to the inside of the circumference, and the rough machining electrode 22 is moved to the disk 2. Electric discharge machining is performed on the second blade 3 while the blades are in contact with each other.

When the rough machining of the second blade 3 is completed, the rough machining electrode 22 moves from the circumference of the disk 2 in a direction away from the disk 2 and waits again at the machining origin, and the turbine rotor 1 rotates at an A degree index. do. Similarly, rough machining power 11
The rough machining by the movement of i22 and the index rotation of the turbine rotor 1 by A degrees are repeated until the first blade 3 reaches the position of the second machining head 17. Here, it is assumed that the number of repetitions until the first blade 3 reaches the position of the second processing head 17 is N times.

When the A degree indexing rotation of the turbine quarter 1 is repeated N times, the first blade 3 reaches the position of the second processing head 17. At the same time that the first blade 3 reaches the position of the second processing head 17, the unprocessed Nth blade 3 reaches the position of the first processing head 16.

The second machining head 17 moves in the X, Y, and Z axis directions while being controlled, and finishes the first blade 3 that has been rough-machined. The finishing electrode 23 provided at the tip of the second processing blade 17 is of a full type and has the same shape as the finished surface between the blades 3. The finish machining electrode 23 is moved from the circumference of the disk 2 to the inside of the disk 2 from which the rough machining type has been removed, and the finishing allowance is removed by electric discharge machining. At the same time as the finishing electric power 11i23 performs finishing machining on the first blade 3, the rough machining electric power 11i22 also performs rough machining on the Nth blade 3. When finishing machining of the first blade 3 and rough machining of the N@th blade 3 are completed, the rough machining electric fii 22 and the finishing machining electrode 23 move in a direction away from the disk 2 and return to the machining origin. and wait. When the rough machining electrode 22 and the finishing machining electrode 23 are on standby, the turpin rotor 11 rotates at an index angle of A degree, and the first blade 3 advances toward the first machining head 16, and the rough machining electrode 22 and finishing machining are performed again. Rough machining and finishing machining are simultaneously performed using the electrode 23. Simultaneous machining of the rough machining electrode 22 and the finishing machining electrode 23 is performed by the number of times that the first blade 3 subjected to finishing machining reaches the position of the rough machining electrode 22 (number of blades - N).
repeated until. When the first blade 3 reaches the position of the first machining head 16, the rough machining electrode 22 is retracted to the origin of the device and the rough machining of the turbine rotor 1 is completed.

After the rough machining electrode 22 completes the rough machining, the turbine rotor 1 is further subjected to eight A-degree index rotations and finish machining is performed by moving the finish machining electrode 23. When the finishing electrode 23 completes ljN finishing operations, the finishing electrode 23 moves from the circumference of the disk 2 in a direction away from the disk 2 and retreats to the origin of the apparatus. The finishing electrode 23 is retracted to the origin of the device, and the electrical discharge machining of the turbine rotor by the electrical discharge machining device 8 of this embodiment is completed.

During electrical discharge machining, wear of the rough machining die 22 and the finishing electrode 23 is detected by an NC device. The rough machining die $1i22 and the finishing electrode 23 whose wear has been detected are sequentially replaced with replacement electrodes provided in the first electrode rack 31 and the second electrode rack 32.

The electric discharge machining device 8 of this embodiment has a first machining head 16 provided with an electrode 22 for rough machining and a second machining head 17 provided with 11 poles 23 for finishing machining, so that the blade 3 can be rough-machined and finished. Machining can be performed simultaneously, and the inclined rotary table 12 can be rotated at an index angle of A degree, so that electric discharge machining of the blade 3 can be performed continuously and automatically by rotating the turbine rotor 1 at an index angle of A degree. Rough machining electrode 2
Since the electrodes 2 and 23 for finishing machining are automatically replaced when wear is detected in advance, electrical discharge machining can always be performed using electrodes that do not wear out, and the thickness of the blade 3 does not become uneven, making it possible to form a highly accurate profile.

<Effects of the Invention> A single electric discharge machining device is provided with two independent first machining heads and a second machining head, and the index rotation of the tilted rotary table and the movement of the first machining head and the second machining head are performed. Since it is controlled by an NC device, it is possible to perform two types of machining on the turbine rotor at the same time. During electrical discharge machining, wear of the machining electrodes is detected by the NC device, and the electrodes are replaced at the appropriate time using the electrode replacement device. Therefore, electrodes that do not wear out are always used, and electrical discharge machining of the turbine rotor can be performed continuously and automatically. .

Therefore, electric discharge machining of the turbine rotor can be performed continuously and automatically during setup, so that the machining cycle time can be shortened, and a machining electrode that does not wear out is always used, making it possible to perform highly accurate electric discharge machining.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an electric discharge machining apparatus which is an embodiment of the present invention, FIG. 2 is a partially enlarged view of an electric discharge machining apparatus which is an embodiment of the present invention, and FIG. 3 is a perspective view of a turbine rotor. FIG. 4 is a diagram showing the state of finishing of the blade by conventional electric discharge machining, FIG. 5 is a diagram of the rough machining of the blade by electrical discharge machining, and FIG. 6 is a diagram of the state of finishing machining of the blade. Further, in the figures, 1 is a turbine rotor, 8 is an electric discharge machining device, 11 is a machining liquid tank, 12 is a tilted rotary table, 16 is a first machining head, 17 is a second machining head, and 20 is a first electrode. 21 is a second electrode hand, 26 is a first electrode exchange device, 27 is a second electrode exchange device, and 35 is an NC device. Figure 1/ Figure 2 Figure 3

Claims (1)

[Claims] A machining liquid tank provided in the PET, a tilted rotary table provided in the machining liquid tank for holding a turbine rotor and indexing rotation of the turbine rotor, and a tilted rotary table provided in the bed with the tilted rotary table in between. a first machining head and a second machining head supported movably in position relative to the tilted rotary table; An electrode hand that holds a processing electrode for processing blades of a turbine rotor, and a rack provided in each of the first processing head and the second processing head and storing a plurality of the processing electrodes, and the rack and an electrode exchange device comprising an exchanging means for exchanging the machining electrode between the electrode hand, rotational movement of the inclined rotary table, positioning movement of the first machining head and the second machining head, and the An electric discharge machining apparatus for a turbine rotor, comprising: an NC device for controlling exchange of the machining electrodes by an electrode exchange device.