RU2774497C1 - Method for electrochemical removal and rounding of edges in intercepting channels - Google Patents

Abstract

FIELD: electrochemical processing.

SUBSTANCE: invention relates to the electrochemical processing of parts made of aluminum alloys and can be used in the manufacture of high pressure fuel pump flanges. Method for electrochemical deburring and edge rounding in intersecting channels of aluminum alloy parts includes placing a tool electrode near the surface to be treated, supplying an electrolyte pumped with a given pressure into the interelectrode gap, turning on the current and performing processing for a given time, removing the tool electrode, while processing is carried out at a current of 130 A and a voltage of 130 V.

EFFECT: invention provides intensification of the process of electrochemical deburring and rounding of edges in the intersecting channels of parts made of aluminum alloys by increasing the electrical operating parameters, and also allows simultaneous deburring and rounding of sharp edges in several holes in the part.

1 cl, 1 ex

Description

SUBSTANCE: invention relates to electrochemical processing of parts made of aluminum alloys and can be used in the manufacture of flanges for high-pressure fuel pumps of Common Rail systems.

In the manufacture of parts, including those made of aluminum alloys, there is a need to remove burrs and round off sharp edges at the intersections of internal channels. Performing each of these operations mechanically is not always possible, therefore, deburring and simultaneous rounding of edges at the intersections of channels by electrochemical processing has become widespread.

For parts made of aluminum alloys, it is recommended to use sodium nitrate as an electrolyte component with a concentration of 100 g / l to 300 g / l (Amitan G. L. et al. Handbook of electrochemical and electrophysical processing methods. - L .: Mashinostroenie, Leningrad. otd., 1988. - 720 p. S. 42).

It is known that the intensification of the process of deburring and rounding edges can be achieved by increasing the voltage and current strength: “the voltage on the electrodes is 20 V, and the current strength is 1000 A” (ECHO Basics [Electronic resource]. URL: https://metallicheckiy- portal.ru/articles/obrabotka/exo/osnovi_exo/ (date of access: 11/30/2021)).

It is also known that in various technological installations for deburring by the electrochemical method, it is allowed to increase the current strength to 4000 A, the voltage to 60 V. (Karlina Yu.I., Gozbenko V.E., Kargapoltsev S.K. burrs from small-sized high-precision parts of microwave electronics // Modern technologies. System analysis. Modeling. 2020. No. 2 (66) URL: https://cyberleninka.ru/article/n/perspektivy-primeneniya-elektrofizikohimicheskih-metodov-udaleniya-zausentsev -s-malogabaritnyh-vysokotochnyh-detaley (date of access: 11/30/2021).

A known method of electroerosive-chemical deburring, including the supply of voltage to the electrodes in the presence of an electrolyte and the creation of a temperature gradient along the height of the interelectrode gap towards the direction of the current, and the electrolyte exchange rate, voltage and current density are set from the condition for the formation of a vapor-gas phase in the anode layer (A.S. SU 1811448, published April 23, 1993, Bulletin No. 15).

The disadvantages of the known solutions include the lack of rounding of sharp edges on the details when using it.

The closest in terms of essential features - the prototype of the claimed invention - is a method for electrochemical deburring and rounding edges in intersecting channels, including the following transitions (US Pat. RU 2699140, publ. 03.09.2019. Bull. No. 25):

- placement of an electrode-tool with bare areas near the surface to be treated,

- supply of electrolyte into the interelectrode gap,

- switching on electric current

- exposure for a given time,

- removal of the electrode-tool.

According to a well-known solution, the supply of electrolyte into the interelectrode gap is carried out through an intermediate element - a moisture-absorbing material, which for this purpose is wound on the working end of the tool electrode and connected to a current source. The end with the wound moisture-absorbing material is dipped into the electrolyte, then it is installed in the hole in the part, where it is necessary to remove the burrs and round the edges. The duration of a single treatment is from 10 to 20 s. After the current is turned off, the electrode is removed, re-dipped in the electrolyte. In this case, according to the authors of the known solution, the sludge is washed off from the moisture-absorbing material. If necessary, the tool-electrode with the moisture-absorbing material wound and re-wetted is reinstalled into the hole in the part for additional processing. The implementation of the well-known solution, according to its authors, is possible when using the battery as a power source.

The disadvantages of the known solutions include the use of additional moisture-absorbing material, which increases the complexity of the operation. This circumstance is aggravated if it is necessary to process several sequentially located places in the hole of the part, since it requires winding the moisture-absorbing material on the bare areas of the tool electrode opposite each of these places. Dipping a long tool electrode into the electrolyte to wash off the sludge and wet the moisture-absorbing material is inconvenient, requires an extended container, and can lead to contamination of the working area with electrolyte dripping from the tool electrode when transferring it from the container with electrolyte to the workpiece and back. The disadvantages also include the limitation of the possibility of intensifying the processing process in terms of electrical regime parameters, which is associated with the use of a battery.

The technical objective of the present invention is to create a method for electrochemical deburring and rounding edges in intersecting channels, which allows simultaneous processing of several sequentially located places in a hole in a part, which does not require the use of additional - moisture-absorbing - material and allows intensifying the processing process by increasing the electrical operating parameters.

SUBSTANCE: method for electrochemical deburring and edge rounding in intersecting channels of aluminum alloy parts includes placing a tool electrode near the surface to be treated, supplying an electrolyte pumped with a given pressure into the interelectrode gap, turning on the current and performing processing for a given time, removing the tool electrode, while processing is carried out at a current of 130 A and a voltage of 130 V.

The set technical problem is solved through the joint application of the following measures:

- use of an electrode-tool without moisture-absorbing material,

- pumping electrolyte into the interelectrode gap formed by the outer surface of the tool electrode and the inner surface of the hole in the workpiece, with a given pressure,

- implementation of the processing process at a current strength of 130 A, a voltage of 130 V.

The implementation of the processing process at a voltage of 130 V is a new, essential feature that contributes to obtaining the claimed technical result.

The voltage value of 130 V was selected by the applicant empirically for processing parts made of aluminum alloys. The voltage values given in the educational and reference literature differ significantly (by 2 or more times) from that proposed in this application. This gives the Applicant reason to consider the proposed feature as meeting the "novelty" criterion.

Proposed as the present invention, the method of electrochemical deburring and rounding edges in intersecting channels is carried out in the following sequence:

Stage 1: the workpiece is installed and fixed in the fixture.

The design of the fixture is not subject to protection in this application.

Stage 2: the tool electrode is installed in the holes of the part to be processed.

The design of the electrode-tool is not subject to protection in this application. The number of electrode-tools for simultaneous processing is selected depending on the processing scheme and in the general case can be more than one.

Stage 3: electrolyte is fed into the interelectrode gap.

Stage 4: turn on the power supply.

Stage 5: maintain the specified processing time.

Stage 6: turn off the power supply manually or automatically

Stage 7: turn off the electrolyte supply.

Stage 8: dismantle the machined part from the fixture.

An example of the proposed method for electrochemical deburring and edge rounding in intersecting channels.

The part “Flange A-08-004-08-01-00” of the high-pressure fuel pump of the KAMAZ-740 engine was processed.

Purpose of machining: Simultaneous deburring and rounding of sharp edges in 10 holes (12 intersections) in a workpiece using 7 electrodes. Diameters of intersecting holes: from ∅3.5 to ∅14 mm.

Detail material: alloy AK7 h GOST 1583-93.

Electrolyte: sodium nitrate 12.5%, artesian water - the rest.

Electrolyte temperature before treatment: 23°C.

Electrolyte supply pressure at the entrance to the interelectrode gap: 2 kg/cm ² .

Electrical parameters of the operation: current strength - 130 A, current voltage - 130 V.

The treatment was carried out for 36 s. After processing, the first part was opened for control. The quality of the roundings is satisfactory. Burrs were not found.

The technical result of the implementation of the proposed method of electrochemical deburring and rounding of edges in intersecting channels is to provide the possibility of intensifying the processing process by increasing the voltage. The development has been introduced into serial production at AZPI Management Company LLC.

Claims (1)

A method for electrochemical deburring and edge rounding in intersecting channels of aluminum alloy parts, including placing a tool electrode near the surface being machined, supplying an electrolyte pumped with a given pressure to the interelectrode gap, turning on the current and performing processing for a given time, removing the tool electrode, which differs the fact that the processing is carried out at a current of 130 A and a voltage of 130 V.