RU2058863C1 - Method of circular electrochemical treatment of vanes of gas turbine engine - Google Patents

Abstract

FIELD: production of comple shape vanes of gas turbine engines with high accuracy of their dimensions. SUBSTANCE: method comprises steps of working basic surfaces of vanes, namely of two centring holes on ends of a joint portion, one of these ends and a cone surface of a boss on an end part of the vane; securing a blank in a working chamber according to the basic surfaces and working it by two tool-electrodes; providing a profile of the tool-electrodes, being approximately the same as a profile of the vane; setting motion direction of each tool-electrode in such a way, that it forms an acute angle with an axis of the vane, having an apex, turned to a side of the vane flange; selecting a value of the above mentioned angle, equal to 60-80 degrees; performing flowing through of an electrolyte upon treatment process through an interelectrode gap at a side of the end portion of the vane and driving the tool-electrodes to syncronous-descrete motion with periodical touching of the vane. The method allows to perform treatment of the vane itself, its flanges, edges and joining portions over one operation with minimum error and with a desired smoothness of the surface, being treated. EFFECT: enhanced efficiency of the method, providing high- quality of vane surface, being treated. 2 cl, 2 dwg, 1 tbl

Description

 The invention relates to the manufacture of axial multistage compressors for advanced gas turbine engines and is intended for the manufacture with high accuracy of blades of complex geometry by the method of circular electrochemical processing (ECHO).

Known dimensional ECHO pen compressor blades with two electrodes-tools (ZI), including periodic correction of the interelectrode gap (ME) and the supply of electrodes of technological current pulses [1]
This technology is implemented in the machine ECS-10V, RPO "Electromechanics", Rzhev. This is a fairly accurate process. However, the reliability of existing circuits of pulsed current sources (PIT-1600, IPI-5000) is very low, manual refinement of the radius of the transition from the pen to the lock and the lock shelf is required, which inhibits the widespread introduction of pulsed ECHO.

 At present, a pulsed ECHO with vibration of electrodes and synchronous generation of technological current has been developed and is being applied at KNPO Trud [2, 3, 4] The technology is implemented in the machines SEP-9021, NITI, RPO Electromechanics of Rzhev; 44221FU NPO "Armstanok".

 A pulsed ECHO with vibration of the electrodes allows one to determine the position of the EI from reflected signals, to restore the interelectrode medium in the pauses between pulses, to control the duty cycle of the generated process current pulses, and the ratio of the duration of these pulses and pauses.

 The disadvantages of this process are the difficulty of regulating the process of electrochemical processing, a rather complex and unreliable design of existing vibrators, a large energy intensity of the process.

Closest to the proposed one is a method for ECHO processing of parts of complex shape, in which the blade blank is placed in the working chamber, fixed on pre-processed base surfaces and formed by two tool electrodes with voltage applied to the electrodes and the workpiece, pumping the electrolyte through the interelectrode gap and setting electrodes of synchronous-discrete movement with periodic palpation of parts, while the profile of the working surfaces of the electrodes is made close to this profile parts [5]
The existing method does not allow the processing of the interface, in particular the radius of the transition from the profile to the castle part of the scapula, in one operation with the processing of the pen, shelves and edges to ensure the required surface cleanliness and requires the use of manual labor.

 In addition, the basing system and the structure of the technological process do not provide blades of accuracy class I, since the technological process is based on the use of an inaccurate basing scheme for the design basis of the shank of the blade.

 When developing small-sized engines of new generations, the production was tasked with creating a technological process that ensures stable production of compressor blades according to class I accuracy with low laboriousness.

To solve this problem, a method was developed for the circular electrochemical processing of GTE blades, according to which the blade blank is placed in the working chamber, fixed on pre-processed base surfaces and formed by two tool electrodes with voltage applied to the electrodes and the workpiece, pumping the electrolyte through the interelectrode gap and setting electrodes of synchronous-discrete movement with periodic palpation of the blades, while the profile of the working surfaces of the electrodes perform b izkim to a predetermined profile of the blade, and the direction of movement of each of the electrodes is set so that it forms with the blade axis an acute angle whose apex faces the blade flange, the size of the angle selected in the range ^of 60-80, and the electrolyte is carried out by the transmission end of the feather of the scapula.

 The blades are based on two center holes in the ends of the castle, one of these ends and the conical surface of the boss at the end of the pen.

It was established experimentally that the supply of electrolyte from the end portion of the blade, while tilting the electrode-tool to the axis of the blade at an angle of ^about 60-80 allows the final treatment radius transition from profile to the joint part of the blade shape and are not limited shelf width.

The angle of inclination of 60-80 ^about to the axis of the blades is the most optimal. At an angle greater than 80 ^about , the formation of shelves is not guaranteed, especially if they are developed, and at an angle less than 60 ^about , the accuracy of processing the profile of the blade deteriorates and the manufacture and debugging of tool electrodes is complicated.

An experimentally found scheme for basing a blade (along two center holes at the ends of the shank, one of the ends and a conical surface at the end of the boss feather), based on the principle of combining design and technological bases, in conjunction with a new technological processing scheme (pumping electrolyte along the axis of the blade from the side end of the blade and moving the tools of the electrodes at an angle ^of 60-80 to the blade axis) allowed to carry out processing of the pen, shelves, edge and mating portions in a single operation with minimal nd error (based error does not exceed 3 microns for reinstallation 100) and providing a desired surface finish.

 This allows you to completely eliminate manual labor on the formation of the elements of the flowing part of the scapula, to maintain a single base for all operations of manufacturing the scapula, including control.

 Studies have shown high stability of the profile elements (deviations in the batch do not exceed 0.02 mm), which allows you to go to control the profile geometry of the first and last two blades from the batch being processed.

In FIG. 1 is a diagram of the processing of locations for the base of a blade blank for circular ECHO; in FIG. 2 diagram of the installation and processing of the blades by the proposed method, a longitudinal section;
In FIG. 1 and 2 show the workpiece 1, the ends 2 of the workpiece, the center holes 3, the end 4 of the boss, the cone 5 of the boss, the sole 6 of the workpiece, a rigid fixture 7 with centers for basing, a sealed chamber 8, electrodes-tools 9, hydraulic cylinders 10, rods 11 hydraulic cylinders, current lead 12, spring 13, which provides a calibrated force to compress the current lead, hydraulic cylinder 14 of the blade.

 The method was tested in the pilot production of the FCM.

A batch of blades 870100403 was made from VT-8 material in an amount of 1000 pcs. Used stamped blanks with a stock allowance of 1.5 $\genfrac{}{}{0ex}{}{\text{+0.5}}{\text{-0.3}}$ , measuring 43.2 x 40.2 x 18.5.

 On the machine SM12-250 M1, the ends 2 of the blade lock were milled, two center holes 3 were drilled (see Fig. 1). On the TV-125 lathe, end face 4 and boss cone 5 were machined (Fig. 1). After that, the vertically milling machine BP12 milled the sole 6 of the paddle lock (Fig. 1).

 Electrochemical processing was performed on a modernized machine EHS-10B.

 The blade blank was installed in the fixture 7, clamped with the help of two cylinders and pushed with the third cylinder 14 (Fig. 2).

 The electrolyte was pumped along the axis of the scapula from the end of the pen of the scapula (Fig. 2). Using the electronic control unit, the operating current was turned on and the processing started.

 The upgraded control system of the machine included a power source, control unit, step drive, spools and other elements. The preload force of the current supply 12 was provided by the spring 13 (Fig. 2).

 All technological steps were carried out in accordance with the claims.

 The required surface shape and dimensions of the blade were obtained as a result of the movement of the electrode-tools made of stainless steel and having a shape close to the equidistant finally processed surface of the blade.

 The scapula pen was processed simultaneously from two sides.

 The movement of the electrodes-tools produced before they were closed.

The processing cycle included the following operations:
synchronous supply of electrodes to the part and "feeling";
electrode removal to the working gap;
fixing the electrodes or turning on the supply of electrodes while turning on the operating current;
holding a working period, i.e. processing for a given time;
shutdown of working current;
electrode removal to an increased gap for washing the interelectrode gap;
repeated "feeling". Processing modes: Operating voltage, V 9 Operating current, A 800 Duty rate 0.5
The electrolyte composition is 7.5% KNO ₃ + 9% NaCl + air. The temperature of the electrolyte T 20-25 ^about C. The electrolyte pressure P _el 4-4,25 kg / cm ² . The angle of movement of the EI to the axis of the scapula was set at 50, 60, 70, 80, 90 ^about . The calibrated force of the current lead is 200 kg. The interelectrode gap was set 0.05-0.1 mm. The processing time was 7-8 minutes.

 The geometry of the profile elements of the feather blades was measured using a Gamma measuring machine and an Opton measuring machine.

 Tests have confirmed stable processing quality indicators and reduced labor intensity. The table shows comparative indicators with the basic version of the ECHO method implemented in the ECS-10A machine, damn. G817-50, 4AT, RPO "Electromechanics" of Rzhev.

 The invention provides stable processing of a wide range of blades in class I accuracy, 3 times reduces the manufacturing cycle of the blades by eliminating manual refinement when forming the geometry of the profile and 3-4 times reduces their cost.

 The blades processed by this technological process have high stability at their own frequencies (deviations in the batch do not exceed 0.02). This allows you to go to control the geometry of the profile of the first and last two blades.

 The blades made by this technology will allow to provide the calculated coefficient GDU and compressor efficiency.

Claims (2)

1. METHOD FOR A CIRCULAR ELECTROCHEMICAL TREATMENT OF GTE BLADES, in which the blade blank is placed in the working chamber, fixed on pre-treated base surfaces and formed by two tool electrodes with voltage applied to the electrodes and the workpiece, pumping the electrolyte through the electrode gap and setting the electrode synchronously moving with periodic palpation of the blade, while the profile of the working surfaces of the electrodes is close to the specified profile of the blade, and systematic way the movement of each of the electrodes is set so that it forms with the blade an acute angle axis, the apex of which faces the blade flange, characterized in that the angle between the direction of movement of each of the electrodes and the blade axis is selected in the range of 60 - 80 ^o, while feeding electrolyte carried out from the end of the pen blade.  2. The method according to claim 1, characterized in that the blade blank is secured by two center holes in the ends of the castle, one of these ends and the conical surface of the boss at the end of the pen.

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