Closed - type blade ring screw - in type cascade channel electrochemical machining device and method

Abstract

The present invention relates to a closed - type blade - ring screwed - in cascade - channel electrochemical machining device and method, belonging to the field of electrochemical machining. The device mainly includes a support disk, a workpiece, an insulating gasket disk, a tailstock, a cathode rod, a cathode head, etc. During machining, the cathode remains fixed, and the workpiece rotates and feeds along an arc - shaped trajectory in the axial direction of the blade, gradually machining the cascade channel into shape. A group - slit structure is arranged on the cathode head to ensure sufficient supply of electrolyte to the machining area. A reverse - flow groove is arranged on the insulating gasket disk, so that when the cascade channel is about to be machined through, the electrolyte will not disperse, but under the action of the reverse - flow groove, it will be flushed back to the machining area, preventing liquid shortage and ensuring machining stability.

Description

Technical Field

[0001] The present invention provides a closed - type blade ring screw - in type cascade channel electrochemical machining device and method, belonging to the technical field of electrochemical machining. Background Technique

[0002] Both the closed - type blade ring and the integral blisk are aero - engine parts that need to withstand high - temperature and high - pressure gases, centrifugal force, shear force, cyclic stress, and bending stress. The closed - type blade ring is another important aero - engine part after the integral blisk, and it has more advantages in terms of structural simplification and weight reduction. For the machining of the closed - type blade ring, traditional cutting machining methods are gradually replaced by electrochemical machining technology with high machining efficiency and no residual stress due to problems such as easy generation of burrs, flash, and residual stress on the workpiece surface.

[0003] In the article "Research on High - Efficiency Rough Grooving Machining Technology for Closed - Type Blade Rings of Superalloys", a milling method for the blade ring cascade channel that adjusts the cutter axis vector direction layer - by - layer and region - by - region is proposed, which improves the material removal rate and machining efficiency. However, the tool wear and consumption are large, and the milling cycle is long.

[0004] Chinese Patent CN108994402A proposes a method for electrochemical forming machining of the blade profile for an integral closed - type blade ring, its fixture and electrode. Relying on the electrode profile to ensure the blade and air - flow channel profiles, this method is not limited by the complexity of the blade profile. By using a formed electrode and cooperating with an electrode fixture, multi - axis linkage electrochemical forming machining can be realized on an electrochemical forming machine. However, this method has low machining efficiency, large residual stress in the machined workpiece, and poor surface quality.

[0005] Chinese Patent CN108104880A proposes a preparation method for a blade ring. First, a blade - ring core workpiece is prepared, and then the prepared blade - ring core workpiece is fused with a ring - shaped alloy forging with a ring - shaped groove to form a blank of a closed - type blade ring made of continuous fiber - reinforced metal matrix composite.

[0006] Chinese Patent CN103769663B proposes a special variable - cutting - width three - edged milling cutter for slotting integral blisks to solve the problems of easy tool wear, poor chip removal, poor machining quality, non - adjustable blade position, low machining efficiency, high production cost, difficult tool manufacturing, and inconvenient tool installation when the existing three - edged milling cutter is used for slotting integral blisks.

[0007] Due to the structural limitation of the outer hub of the closed - type blade ring, traditional trepanning electrochemical machining methods and radial grooving methods cannot be applied. For the narrow and twisted closed - type blade ring flow channel, new machining difficulties exist in aspects such as cathode profile design, cathode trajectory control, and insulation.

[0008] In view of the above, the current grooving processing methods for closed bladed rings cannot achieve efficient, high-quality, and high-precision processing. There is an urgent need to conduct research on the electrochemical machining of the bladed ring cascade channels. Summary of the Invention

[0009] The purpose of the present invention is to provide a closed bladed ring screw-in type bladed cascade channel electrochemical machining device and method to effectively solve the drawbacks of the existing processing means that require the use of sacrificial discs, resulting in waste, and the problem of uneven grooving machining allowance.

[0010] A closed bladed ring screw-in type bladed cascade channel electrochemical machining device, characterized in that:

[0011] It includes a support disc, an insulating pad disc, a workpiece, a cathode, and a tailstock;

[0012] The support disc is a complete disc structure, and its front and rear end faces are respectively connected and attached to the rear end face of the insulating pad disc and the machine tool spindle; the insulating pad disc is closely attached to the front end face of the support disc, and is a fan-shaped segment structure as a whole. There are several reflux grooves with the same size on it. The reflux grooves are located on the front end face of the insulating pad disc and are symmetrically distributed around the center at equal angles. The end face size of the reflux groove is slightly larger than the end face size of the cathode head, and the depth is slightly smaller than the thickness of the cathode head, for accommodating the cathode head that partially extends out after machining; the rear end face of the workpiece is attached to the front end face of the insulating pad disc;

[0013] The cathode is composed of a cathode head and a cathode rod; the outer wall of the cathode rod body is insulated; the cathode head is located in front of the cathode rod and is connected to the front end face of the cathode rod. There are several liquid outlet group slits on the cathode head, and the front end face of the cathode head is opposite to the front end face of the workpiece; the cathode rod is composed of a curved cathode rod body and a cathode rod base; the cathode rod body is a curved thin-walled structure with a liquid inlet channel inside; the outer wall contour of the cathode rod corresponds to the contour of the bladed cascade channel, and the cathode rod body gradually shrinks from the cathode head to the cathode rod base direction, showing a horn shape as a whole; the cathode rod base is connected to the front end face of the tailstock, and the other end of the tailstock (5) is connected to the machine tool;

[0014] The processing method of the closed bladed ring bladed cascade channel screw-in type electrochemical grooving processing device is characterized by including the following processes:

[0015] Before the start of processing, the front end face of the cathode head is opposite to the front end face of the workpiece to ensure the initial machining gap;

[0016] During the processing, the cathode remains fixed, and the workpiece performs a screw-in type processing along the axial arc trajectory of the blade; as the processing progresses, the cathode rod body continuously enters the workpiece, and the insulating layer on its outer wall protects the inner surface of the processed channel from secondary corrosion.

[0017] At the end of processing, the cathode head extends out parallel to the rear end face of the workpiece and enters the reflux groove of the insulating pad disc;

[0018] After the machining is completed, the workpiece withdraws along the reverse machining trajectory.

[0019] The beneficial effects of the present invention are as follows:

[0020] (1) During machining, the cathode remains fixed, and the workpiece is machined in a spiral-in manner along the axial arc trajectory of the blade. By approximating the blade concave and convex surfaces as curvature radii to find the feed trajectory, the maximum allowance difference between the blade concave and convex surfaces is minimized, effectively improving the uniformity of the allowances on the blade concave and convex surfaces. At the same time, this method has strong versatility. For different structural blade rings, the feed trajectory can be adjusted according to the blade bending and torsion degree and the characteristics of the cascade channel shape to achieve machining.

[0021] (2) A group-slit type liquid outlet structure is arranged on the cathode head, making the flow fields in the gaps of the blade concave, convex, inner and outer flow channels uniform and stable during machining, ensuring the sufficiency and uniformity of liquid supply, and avoiding machining instability or even arcing phenomena caused by uneven electrolyte distribution.

[0022] (3) The shape of the cathode rod is designed according to the shape of the cascade channel of the blade ring, avoiding interference between the cathode rod and the machined channel during machining. At the same time, the outer wall of the cathode rod is insulated to prevent the cathode rod from causing secondary corrosion to the inner and outer flow channel surfaces and the blade concave and convex surfaces of the machined channel.

[0023] (4) A reverse flow groove is arranged on the insulating pad, so that when the cascade channel is about to be machined through, the electrolyte will not flow out in all directions, but accumulate in the reverse flow groove and be flushed back to the machining area, preventing liquid shortage and ensuring machining stability. Description of the Drawings

[0024] Figure 1 is the overall assembly schematic diagram of the present invention;

[0025] Figure 2 is the structural schematic diagram of the insulating pad;

[0026] Figure 3 is the overall structural schematic diagram of the cathode;

[0027] In the figure: 1 - support disk, 2 - insulating pad, 3 - cathode, 4 - workpiece, 5 - tailstock, 6 - reverse flow groove, 7 - cathode head, 8 - cathode rod, 9 - liquid outlet group slit. Embodiment

[0028] The following is a detailed introduction to the specific embodiments of the present invention with reference to the drawings.

[0029] Implement the present invention - "Closed - type vane - ring vane - cascade channel screw - in type electrolytic grooving processing device and method". The device includes a support disk, an insulating gasket disk, a workpiece, a cathode, and a tailstock. Among them, the support disk, the cathode, and the tailstock are all made of conductive metal materials, and the insulating gasket disk is made of non - conductive material epoxy resin. The shape of the cathode head is determined according to the part requirements, and the outer shape of the cathode rod is determined according to the processing channel.

[0030] The process of using the present invention for electrolytic grooving processing of the closed - type vane - ring vane - cascade channel includes the following steps:

[0031] Step 1: Install tooling such as the workpiece, the cathode, and the tailstock. The cathode and the workpiece are respectively connected to the negative and positive poles of the power supply; write the feed program for the numerical control machine tool.

[0032] Step 2: Perform tool setting.

[0033] Step 3: Turn on the electrolyte circulation system, adjust parameters such as pressure and temperature, and introduce the electrolyte.

[0034] Step 4: Start the DC power supply, adjust parameters such as voltage, and introduce current.

[0035] Step 5: Start the numerical control program, and the workpiece performs screw - in type processing along the axial arc trajectory of the blade.

[0036] Step 6: After processing, turn off the power supply and the electrolyte circulation system, execute the workpiece retraction program, and tidy up and clean the machine tool.

Claims

1. A closed - type blade - ring screwed - in cascade - channel electrochemical machining device, characterized in that: It includes a support disk (1), an insulating pad disk (2), a cathode (3), a workpiece (4), and a tailstock (5); The support disk (1) is a complete disk structure, and its front and rear end faces are respectively connected to and fitted with the rear end face of the insulating pad disk (2) and the machine tool spindle; The insulating pad disk (2) is closely attached to the front end face of the support disk (1), and is integrally a fan-segment structure, with a number of reflux grooves (6) of the same size provided thereon; among them, the reflux grooves (6) are located on the front end face of the insulating pad disk (2) and are symmetrically distributed at equal angular centers. The end face size of the reflux groove (6) is slightly larger than the end face size of the cathode head (7), and the depth is slightly smaller than the thickness of the cathode head (7), for accommodating the cathode head (7) partially protruding after the processing is completed; the rear end face of the workpiece (4) is fitted with the front end face of the insulating pad disk (2); The cathode (3) is composed of a cathode head (7) and a cathode rod (8); the outer wall of the cathode rod (8) is insulated; the cathode head (7) is located in front of the cathode rod (8) and is connected to the front end face of the cathode rod (8). A number of liquid outlet group slits (9) are provided on the cathode head (7), and the front end face of the cathode head (7) faces the front end face of the workpiece (4); the cathode rod (8) is composed of a bent cathode rod (8) body and a cathode rod (8) base; the cathode rod (8) body is a bent thin-wall structure with a liquid inlet channel inside; the outer wall contour of the cathode rod (8) corresponds to the contour of the cascade channel, and the cathode rod (8) body gradually shrinks from the cathode head (7) to the cathode rod (8) base direction, presenting an overall horn shape; the cathode rod (8) base is connected to the front end face of the tailstock (5), and the other end of the tailstock (5) is connected to the machine tool.

2. The processing method of the closed vane ring screwed-in vane cascade channel electrochemical machining device according to claim 1, characterized in that It includes the following processes: When the processing is not carried out, the front end face of the cathode head (7) faces the front end face of the workpiece (4) to ensure the initial processing gap; During the processing, the cathode (3) remains fixed, and the workpiece (4) performs a screw-in type of processing along the axial arc trajectory of the blade; as the processing progresses, the cathode rod (8) body continuously enters the workpiece (4), and the insulating layer on its outer wall protects the inner surface of the processed channel from secondary corrosion; At the end of the processing, the cathode head (7) extends parallel to the rear end face of the workpiece (4) and enters the reflux groove (6) of the insulating pad disk (2); After the processing is completed, the workpiece (4) exits along the reverse processing trajectory.

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