RU2552204C2 - Edm electrode for electrochemical finishing of 3d-complex structures - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to electrochemical processing of metals and can be used for finishing of 3D complex surfaces. Tool comprises case of dielectric material, EDM electrode secured thereat and connected with negative pole of DC source. Note here that said EDM electrode is provided with means to create the gap between it and processed billet connected to DC source positive pole. Said electrode is composed of an adapter with soft three-ply shell rigidly secured at the case. Note here that shell first ply is made of rubber to make a closed chamber. Second ply is made of metal close-meshed gauze while third is made of non-metallic gauze. Note here that aforesaid case has two holes, one to be connected to pump-compressor outlet. Second hole is to be connected to vacuum pump inlet.

EFFECT: higher quality of finishing, precise geometrical sizes.

2 cl, 2 dwg

Description

The invention relates to the field of electrochemical processing of metals and can be used for electrochemical polishing of various parts with internal spatially complex surfaces with internal slopes.

A device for electrochemical processing is known, selected as a prototype, containing a pen with removable electrodes attached to it, connected by a contact and a wire to the negative pole of the current source [RF Patent No. 2472874, cl. C25F 7/00, C25F 3/16, Hand-held electrode tool for electrochemical polishing of metals, 2013].

This device has disadvantages. Each surface shape needs its own nozzle. Poor processing performance due to manual finishing. The high cost of manufacturing an electrode tool.

The problem to which the invention is directed, is to increase the processing efficiency of spatially complex surfaces with the following technical results: increasing productivity and quality of processing of metal surfaces due to the simultaneous processing of the entire surface of the part; preservation of geometrical parameters obtained before electrochemical polishing in hard-to-reach places of surface transition due to the flexibility of the electrode tool.

This problem is solved in that the tool for electrochemical polishing of metals contains a body made of dielectric material, an electrode tool mounted on it, connected to the negative pole of a direct current source, while the electrode tool is provided on the outside with means for creating a gap between it and the workpiece connected to the positive pole of the direct current source, the electrode tool is made in the form of a nozzle with a soft three-layer shell, rigidly fixed to the housing, p why the first layer of the shell is made of rubber, forming a closed chamber, the second layer is of a metal mesh, and the third is of a non-metal mesh, while in the case there are two holes, one of which is made with the possibility of connecting to the outlet of the compressor pump forcing air and the second - with the ability to connect to the input of the vacuum pump. The bend radii of the three-layer shell should be at least five millimeters.

The implementation of the electrode tool in the form of a nozzle with a soft three-layer shell provides the expansion of technological capabilities due to the possibility of processing various workpieces of complex shape, including with internal shadow slopes.

Rigid fastening of a soft three-layer shell on the body ensures uniform fit of the surface of the tool electrode over the entire inner surface of the workpiece.

The implementation of the first layer of rubber, forming a closed chamber, ensures the tightness of the internal volume of the tool electrode, which allows you to change its volume in the direction of increase.

The implementation of the second layer of metal mesh creates a cathode with a maximum working area, which ensures a uniform surface process of electrochemical processing.

The implementation of the third layer of non-metallic mesh ensures uniformity of the gap between the tool electrode and the surface of the workpiece, because of this processing occurs evenly over the entire surface on which the soft tool electrode is located, which ensures the quality of polishing.

The implementation in the housing of two holes: one for connecting the output of the pump-compressor forcing air, the other - the inlet of the vacuum pump, ensures the rapid formation of the surface of the tool electrode of the equidistant machined surface for processing, including with internal slopes, and removing the electrode after treatment from the cavity blanks.

The bending radius of the three-layer shell of at least five diameters ensures the manufacturability of the electrode tool, since smaller curvatures can lead to creases in the metal mesh.

The invention is illustrated by drawings: in FIG. 1 shows a general view of a soft tool electrode in the form of a three-layer shell in an inoperative state; FIG. 2 - tool in working condition.

The device (Fig. 1, 2) contains a housing 1 of dielectric material, in the center of which a protrusion is made, on which a soft electrode tool is mounted, consisting of a three-layer shell, the first layer 2 of which is made of non-metal with a high coefficient of elasticity, for example, rubber; the second layer 3 is made of a metal mesh, for example of copper wire; the third layer 4 is made of non-metallic mesh, for example rubberized fabric, the cellular area of which is 10-20 times larger than that of a metal mesh. Two pumps are connected to the holes 5 of the housing 1. The compressor pump 6 creates a pressure inside the shell. A vacuum pump 7 pumps the medium out of it. On the housing 1, pins 8, screws 9 are installed, a wire 10 is attached from the negative pole of the current source (not shown), which is connected to a metal grid 3. A wire 11 from the positive pole of the DC power source is attached to the workpiece 12. Holes 13 are used to supply the electrolyte , for outlet - holes 14.

The device operates as follows. To perform electrochemical polishing, the workpiece 12 is connected by a wire 11 to the positive pole of a direct current source, and the tool electrode through a wire 10 to the negative pole. The housing 1 with a fixed soft three-layer tool-electrode is mounted on the upper end of the workpiece 12 using pins 8 and screws 9, and using the pump-compressor 6 pump pressure inside the tool electrode until the inner surface of the workpiece 12 is completely covered with an equidistant gap throughout the volume, which provides the third layer 4. Then, through the holes 13, an electrolyte is fed, which is poured through the holes 14 into a drain tank (not shown). When filling the entire gap between the workpiece 12 and the tool electrode, a constant current source is turned on, an electrical circuit is closed, and the process of electrochemical polishing begins. Polishing time, current, electrolyte density are selected empirically depending on the material being processed and the surface roughness. After certain intervals, the polishing process is interrupted, the device is de-energized and the electrolyte is pumped, because at the bottom of the matrix, a reaction product is collected - a slurry, which complicates the polishing process. At the same time, the vacuum pump 7 is turned on and the soft tool electrode is evacuated, and it is compressed, the gap increases, providing a free flow of electrolyte. Then, after turning on the pump-compressor 6, the direct current source is turned on and the process is repeated.

With a current strength of 200-300 amperes, roughness protrusions on the surface to be treated are primarily subjected to anodic dissolution, and the base metal of the part does not have time to react. As a result, the protrusions are removed electrically and the surface roughness is reduced. When you turn off the electrical power, the electrochemical treatment stops. After polishing, the part is washed with water.

Claims (2)

1. A tool for electrochemical polishing of metals, comprising a body of dielectric material, an electrode tool mounted on it, connected to the negative pole of a direct current source, while the electrode tool is provided on the outside with a means to create a gap between it and the workpiece connected to the positive pole of the DC source, characterized in that the electrode tool is made in the form of a nozzle with a soft three-layer shell, rigidly fixed to the housing, with The first layer of the shell is made of rubber, which forms a closed chamber, the second layer is of a fine-mesh metal mesh, and the third is of a non-metallic mesh, and two holes are made in the housing, one of which is made with the possibility of connecting to the outlet of the compressor pump forcing air and the second - with the ability to connect to the input of the vacuum pump. 2. The tool according to claim 1, characterized in that the bend radii of the three-layer shell must be at least five millimeters.

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