SU1539005A1 - Electrode-tool for electrochemical machining - Google Patents

Abstract

This invention relates to electrochemical machining. The purpose of the invention is to improve the processing accuracy by stabilizing the hydrodynamic mode of the process in the interelectrode gap. In the electrode-tool containing a closed chamber connected to the interelectrode gap through the holes located on the working surface of the electrode-tool with a given step. The ratio between the pitch and diameter is selected in the range of 2.5 - 10. 4 Il.

Description

This invention relates to electrochemical machining, and in particular to tool electrodes.

The purpose of the invention is to improve the processing accuracy by stabilizing the hydrodynamic regime in the interelectrode gap.

Fig. 1 shows a diagram of the hydrodynamic regime and the nature of the profile of the surface of the workpiece in the area of the hole in the working surface of the tool electrode with the values of the relative pitch of the holes less than 2.5 and more than 10 ("long-range jet"); in fig. 2 - at its values from 2.5 to 10 (the jet is washed out); in fig. 3 - electrode-tool for electrochemical treatment of cavities, incision; in fig. 4 — node I in FIG. 3. In FIG. 1, 2 denoted by V is the flow rate in the mixing channel of the drift flow and the jet, 1 / and is the flow velocity at the mouth of the jet; A - vortex zone, developing at the hole upstream of the channel; B - vortex zone, “sitting at the mouth of the hole downstream; B - vortex zone in the place of braking with a frontal impact of the jet core on the surface

the workpiece and its branching; c is the error determined by the height of the macro spells under the holes; d, is the error due to jetness, q, is the total error

The electrode tool is a thin-walled shell 1, obtained by metallizing (spraying) the mold surface made by any of the known methods, for example, molding a cavity model (stamping model in the case of a forging die engraving) into a core mixture with, then drying, its flange 2 mounted on the cathode plate 3 with screws 4, reinforced from the inside in its most protruding part by a supporting element consisting of a rod 5 and a sleeve 6 The lower end of the rod 5 is embedded in the The barrel 1, for example, in the process of metallization by spraying or by soldering, moreover, to improve adhesion to the shell 1, a flange (flange) 7 is made on it, and the thread 8 is cut. The shell 1 can be made of stainless steel or copper 1 5-4 mm

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Due to the fact that the supporting element also performs the functions of an additional current lead, the rod 5, the sleeve 6 and the gaskets 9, serving to sample the gap between the sleeve 6 and the cathode plate 3, must be made of a material with good electrical conductivity, such as copper, brass.

The upper threaded end of the rod 5 is inserted into the hole of the cathode plate 3 and secured with a nut 10 with a washer 11.

A rubber gasket 12 serves to seal the closed cavity 13 enclosed between the cathode plate 3, the inner surface of the shell 1 and the outer surface of the sleeve 6, from the side of the pressure pipe.

To supply the electrolyte to the interelectrode gap in the rod 5, a channel 14 is made, and the closed cavity 13 communicates with the interelectrode gap through the holes 15 made in the shell 1 with a pitch taken in compliance with the ratio 5-10, where / a

- hole pitch, d - diameter.

Electrode tool cathode plate 3 is installed on the plate 16, which is fixed on the spindle 17 of the machine.

The interelectrode gap is formed between the surface of the shell of the electrode tool 1 and the surface of the cavity in the workpiece 18.

The flange 2 of shell 1 is made somewhat thicker than the latter — 3-5 mm, and its bearing surface is milled as it is clean until the metallized shell 1 is removed from the mold, which is a parallel base for milling.

The holes for the thread in the flange 2, where the screws 4 are installed, are machined directly after milling the bearing surface using the overlaid and fastened nut 10 with the washer 11 and the gasket 12 of the cathode plate 3 as a conductor

The working surface of the shell 1, after removing the assembled electrode tool from the mold, is perforated with holes 15,

sandblasting to remove particles of the core mixture and, if necessary, polished.

The electrode tool works as follows.

The electrolyte from the pressure line is fed through the channel 14 of the rod 5, not directly into the cavity 13 of the tool electrode. This prevents the impact on the thin-walled shell of the shock load of the electrolyte flow and its deformation. Technological voltage is applied to the shell 1 of the electrode tool and the workpiece 18, due to which there is an intensive dissolution

material details. The electrolyte supplied through the channel 14 into the interelectrode gap flows along it, filling the open cavity 13 of the flow through them through the holes 15 of the shell 1, returns to the interelectrode gap in areas with reduced pressure. Thus, the closed cavity 13 maintains a practically constant static pressure along the length of the gap and stabilizes the hydrodynamic flow regime of the electrolyte.

5 When outflows from the openings 15, the system of electrolyte jets, due to the fact that the relative pitch of the holes is made in the range of 2.5-10, behaves as a system of eroded jets in a drip flow — electrolyte flow along the interelectrode

0 interval (Fig. 2). This ensures that there are no 18 traces of jetting on the surface of the part being machined and a reduction in the size of the macro projections under the holes.

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Claims (1)

Invention Formula Electrode-tool for electrochemical processing, the working layer of which is made in the form of a thin-walled perforated shell forming a chamber for electrolyte, characterized in that, in order to increase the processing accuracy by stabilizing the hydrodynamic mode in the interelectrode gap, the ratio of the step size of the holes in the shell to their diameter lies in the range 2.5-10. Electrode tool 15 / X LDetal 1 Metal fig Electrode - ins / lrunent sixteen I 0u.Z eight FIG. four