RU2027561C1 - Working environment for electro-erosion processing - Google Patents

Abstract

FIELD: electro-erosion processing. SUBSTANCE: additional products of double condensation from higher fatty acids or their bottoms with polyamines, monoalkylphenols and ionol as antioxidant comprising (by weight) 0.5 - 1.5 per cent of products of double condensation from higher fatty acids or their bottoms with polyamines; 1.5 - 4.5 per cent of monoalkylphenols; 0.05 - 0.5 per cent of ionol antioxidant enter working environment for electro-erosion processing on the base of kerosene oil fraction of less than 3 mm²/s viscosity at 20 C, 3 - 5.5 per cent of aromatic, 15 - 20 per cent of paraffin, and the balance being naphthenic hydrocarbons. In so doing, content of products from double condensation of their mixture with alkylphenols is 20 - 25 per cent. EFFECT: highly effective solution. 3 cl, 3 dwg, 2 tbl

Description

 The invention relates to electrical discharge machining (EEO), and in particular to working environments for electrical discharge machining, piercing and cutting and cutting machines.

A number of working media based on hydrocarbon liquids with various additives introduced in order to increase processing productivity and durability of the electrode tool are known:
1. A working medium based on a mixture of industrial oil I20A and kerosene (1.5-2.5) with the addition of barium dialkylmethylene bisphenolate in an amount of 0.1-0.6 wt.% (Ed. St. N 557898, class B 23 P 1/16, 06/23/77).

 2. A working medium based on kerosene with the addition of 10-15 wt.% Sulphurous glycerides of fatty acids in an amount of 10-15 wt.% And polarization in the pauses between pulses with a voltage of 2-12 V (ed. St. N 1131625, class B 23 P 1/100, 12.30.84).

 3. The working medium based on the working fluid RZH-3 with the addition of 0.5-1.0 wt.% Extracted products of nitration of oil (ed. St. N 1555977, CL B 23 H 1/08, 1987).

 However, all these working environments for various reasons have not found industrial application.

 The working medium 1 has a low flash point, high volatility and a short lifetime due to a sharp increase in the viscosity of the liquid as the illumination kerosene evaporates.

 Processing medium 2 is highly toxic, has a sharp, and when heated and decomposed, suffocating odor due to the formation of a large amount of hydrogen sulfide. In addition, the polarization of the additive requires the creation of a special device that is incompatible with commercially available pulse generators.

 The working environment 3 is not effective enough with a relatively laborious process of introducing additives.

The closest to the proposed working fluid is a GC-3 EDM on the basis of the kerosene oil fraction having a viscosity of not more than 3 cSt at ²⁰ ° C, which is a mixture of naphthenic, paraffinic and aromatic hydrocarbons with content of the latter is not more than 5.5% (see. TU 38.101964-83, section 1).

 Experimental studies have shown that in improving the working environments of this type, a large reserve has been laid for improving the technological characteristics of the process, since electrical discharge machining is still a very time-consuming process, especially in finishing and semi-finishing modes.

 The aim of the invention is to increase the productivity of processing at semi-finishing and finishing modes by improving the electrophysical characteristics of the above liquid.

This goal is achieved by the fact that a non-ionic surfactant with a molecular weight of at least 500, which is the products of double condensation of higher fatty acids (VFA) or their bottoms with polyamines, monoalkyl phenols and ionol antioxidant, is additionally introduced into the working medium described above in the following ratio of components, wt.%:
Double Condensation Products
VZHK or their bottoms
residues with polyamines 0.5-1.5
Monoalkylphenols 1.5-4.5
Ionol 0.05-0.5
The proposed working environment is obtained by introducing a heated up to 40-50 ^{° C} foundation consisting of naphthenic, paraffinic and aromatic hydrocarbons (e.g., AJ-3), 2-6 wt.% Additive, which is a 20-25% solution of the condensation products of double IVH or their bottoms with polyamines in monoalkylphenols, and 0.05-0.5 wt.% ionol. The resulting mixture is thoroughly mixed for 10-15 minutes. The prepared solution should have a conductivity in the range 1.5-5.0 x 10 ^-8 1 / Om˙m at 30 ° ^C.

 Samples of liquids with different contents of additional components were tested in a 7 liter overhead bath on a mod machine. 4G721M with a commercially available mod generator. ShGI-63-440. A copper electrode tool and a 45 steel billet with forced circulation of the working medium were used.

The technological parameters of the samples were compared — processing productivity (M., mm ³ / min) and wear of the electrode tool. (γ,%).

 To identify the individual influence of the products of the double condensation of high fatty acids, or their bottoms, or monoalkylphenol, three groups of experiments were carried out (see table 1) at the stage of development of laboratory samples.

 From the experiments of group I it follows that all the components individually do not change the technological parameters of the process.

 From the experiments of group II it can be seen that the products of double condensation of high fatty acids or their bottoms give a positive effect on the performance and wear of the tool only in combination with monoalkylphenol.

 From an analysis of the experiments of groups II-III and the following, the limiting concentrations of the products of double condensation with polyamines and monoalkyl phenols were determined.

Introduced ionol or dibutylparacresol (DBPK) (GOST 10894-64) is a well-known antioxidant. The empirical formula is C ₁₅ H ₂₄ O. The molecular weight is 220.36. (see. Commodity petroleum products, properties and application / Handbook. M.: Chemistry, 1978, p. 85).

 In FIG. 1 shows the dependence of processing productivity on the concentration of the additive and its components; in FIG. 2 - comparative processing performance for various modes when using the proposed working environment; in FIG. 3 - dependence of processing performance on the conductivity of the additive solution in the liquid RZH-3.

 The data confirming the optimality of the selected limits of the additional components of the proposed working environment are given in table. 1 and 2 and in FIG. 1.

 For the optimum concentration of the additive, such additive contents are taken that provide an economically sufficient increase in productivity of at least 1.2 times. This condition, as can be seen from the table. 1 and 2, and FIG. 1, correspond to an additive concentration of 2-6 wt.% Or, respectively, the concentration of products of double condensation of high fatty acids and polyamines - 0.5-1.5 wt.% Monoalkylphenols 1.5-4.5 wt.% And ionol 0.05-0, 5 wt.%.

The optimal content of the products of double condensation of high fatty acids and polyamines in a mixture with alkyl phenols is 20-25%. A larger amount precipitates, a smaller one leads to a decrease in the activity of molecules, the conductivity of the solution, its entry beyond the lower limit of the optimum of 1.5 x 10 ^-8 1 / Ohm˙m (Fig. 3).

Comparative bench tests of the obtained working environment were carried out with the main RZh-3. The processing performance and wear of the electrode tool were determined:
1) for rectangular pulses (copper-steel 45 pair);
2) for comb pulses (copper-steel 45 pair);
3) when processing graphite EI.

 In the entire investigated range of modes, the processing productivity compared to the base fluid, with constant wear of the electrode-tool, increases 1.15-1.8 times (Fig. 2). It is extremely interesting that the roughness of the treated surface does not deteriorate even with a maximum increase in productivity.

 When developing the proposed working environment, we proceeded from the hypothesis built on the basis of the studies.

 Surfactants introduced into the liquid affect the processing through a single act of erosion. The volume of molten metal ejected during a single act of erosion is determined by the kinetic energy of a flying avalanche of positive liquid ions bombarding the workpiece.

In order to facilitate breakdown and increase the kinetic energy of an avalanche of ions, nonionic additives with a molecular mass significantly exceeding the molecular weight of the base were introduced into the liquid (M _osn = 200, M _pris > 500).

 The additive is concentrated in places of increased electric field strength, facilitating breakdown and increasing the number and mass of positive charge carriers, and hence their total kinetic energy.

 The number of charges was judged by the conductivity of the additive solution in the liquid RZH-3. The dependence of processing productivity on conductivity, as one would expect, is optimal (Fig. 3).

 The presence of optimum is explained by the fact that an excessive increase in the number of charge carriers leads to overheating of the metal in the well and its removal in the form of ineffective evaporation instead of pulsed ejection in the form of a melt.

Claims (1)

1. WORKING ENVIRONMENT FOR ELECTROEROSION PROCESSING based on the kerosene oil fraction with a viscosity of not more than 3 mm ² / s at 20 ^o C, which is a mixture of naphthenic, paraffinic and aromatic hydrocarbons with a content of the latter of not more than 5.5%, characterized in that it additionally contains a nonionic surfactant with mol. m. not less than 500 units, which represents the products of double condensation of higher fatty acids or their bottoms with polyamines, monoalkylphenols and antioxidant ionol in the following ratio of components, wt.%:
Products of double condensation of higher fatty acids or their bottoms with polyamines - 0.5 - 1.5
Monoalkylphenols - 1.5 - 4.5
Antioxidant ionol - 0.05 - 0.50
Working medium based on a kerosene oil fraction with a viscosity of not more than 3 mm ² / s at 20 ^o С - Else
2. The medium according to claim 1, characterized in that the ratio of the products of double condensation of higher fatty acids and monoalkylphenols is 1: 3 to 4.

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