RU2676546C1 - Method for abrasive tools impregnation - Google Patents

Abstract

FIELD: manufacturing technology.SUBSTANCE: invention relates to the production of abrasive tools on a ceramic bond and can be used in various branches of engineering. This impregnation method includes the impregnation of the instrument with an aqueous solution of surface-active substances (surfactants) at room temperature for 5–8 minutes and convective drying of the instrument during rotation with a speed of 0.3–0.5 sand temperature 80–95 °C for 2.5–3.0 hours with continuous shaking. Then, the abrasive tool placed in an aqueous surfactant solution is exposed to an alternating magnetic field of intensity H=8–10 MA/m and frequency ƒ=12–15 kHz for 4–6 min, followed by exposure in an aqueous surfactant solution without a magnetic field for 1–2 min.EFFECT: result is a high contact strength of abrasive grains with a ceramic bond.1 cl, 2 tbl

Description

The present invention relates to the production and operation of an abrasive tool on a ceramic bond, namely abrasive wheels, and can be used in various industries.

A known method is the impregnation of an abrasive tool, in which the impregnator used, with increased adhesive ability - a surface-active substance (surfactant) - is dissolved in an aqueous medium, an abrasive tool is placed in it for impregnation, which is then subjected to long-term drying (Aut. St. USSR No. 1726222, CL B 24D 3/34, 1992. Bull. No. 14).

The signs are the same - impregnation of an abrasive tool with an aqueous solution of a surfactant for a certain time, the subsequent stage of drying the tool.

Reasons that impede the task - the complexity of the impregnation process due to the constant change in the composition of the aqueous surfactant solution; the operation of impregnating the instrument with an aqueous solution of surfactant and its subsequent drying from water requires a long period of time.

A known method of impregnation of an abrasive tool, in which the impregnation of an abrasive tool with an aqueous solution of a surfactant from an organic compound is carried out at room temperature for 10-15 minutes with preliminary evacuation, after which the abrasive tool is placed for 10 - 15 minutes. in a container with water at a temperature of 90 - 95 ° C to fix the impregnating composition in its pore space and carry out convective drying of the tool when it is rotated at a speed of 0.3 - 0.5 s ^-1 and a temperature of 80 - 95 ° C for 10 - 12 hours (RF patent No. 2284895, IPC B24D 3/34, BIPM No. 28 (part I), 2006).

The signs are the same - impregnation of an abrasive tool with an aqueous surfactant solution at room temperature, convective drying of it when the tool rotates at a speed of 0.3 - 0.5 s ^-1 and a temperature of 80 - 95 ° C.

The signs that impede the task are the need for prolonged preliminary evacuation of the abrasive tool, its long impregnation with an aqueous surfactant solution, and prolonged convective drying.

The prototype adopted a known method of impregnation of an abrasive tool, in which the latter is impregnated at room temperature in an aqueous surfactant solution, exposed to ultrasonic vibrations of a frequency of 16-18 kHz and an amplitude of 2 to 3 mm for 5-8 minutes, and convective drying is carried out at tool rotation at a speed of 0.3 - 0.5 s ^-1 at a temperature of 80 - 95 ° C for 2.5 - 3.0 hours with continuous shaking (RF patent No. 2574182, IPC B24D 3/34. Bull. No. 4, 2016).

The signs are the same - impregnation of an abrasive tool with an aqueous solution of a surfactant at room temperature for 5-8 minutes. and convective drying of the tool during rotation at a speed of 0.3 - 0.5 s ^-1 and a temperature of 80 - 95 ° C for 2.5 - 3.0 hours with continuous shaking.

Signs that impede the task - a decrease in the contact strength of abrasive grains with a ceramic bond.

The technical result of the invention is the provision of high contact strength of abrasive grains with a ceramic bond.

The technical result is achieved by the fact that an abrasive tool placed in an aqueous surfactant solution is exposed to an alternating magnetic field of intensity H _V = 8-10 MA / m and frequency ƒ = 12-15 kHz for 4-6 minutes. followed by exposure to an aqueous surfactant solution without a magnetic field for 1 to 2 minutes

To achieve a technical result in the proposed method of impregnation of an abrasive tool, comprising impregnating the tool with an aqueous solution of surfactants at room temperature for 5-8 minutes and convective drying of the tool during rotation at a speed of 0.3 - 0.5 s ^-1 and a temperature of 80 - 95 ° C for 2.5 - 3.0 hours with continuous shaking, and placed in an aqueous solution of surface-active substances the abrasive tool is exposed to an alternating magnetic field with a strength of H _V = 8 - 10 MA / m and a frequency of ƒ = 12 - 15 kHz for 4-6 minutes. followed by exposure to an aqueous solution of surfactants without a magnetic field for 1-2 minutes

The implementation of the proposed method of impregnation of an abrasive tool includes the following operations:

- preparation of a surfactant aqueous solution in a special container;

- dipping in an aqueous solution of a surfactant abrasive tool;

- exposure to an aqueous solution of a surfactant with an abrasive tool of a variable magnetic field with a strength of H _V = 8 - 10 MA / m and a frequency of ƒ = 12 - 15 kHz for 4-6 minutes;

- exposure of the abrasive tool in an aqueous solution of a surfactant without a magnetic field for 1 to 2 minutes;

- removing the abrasive tool from the tank with an aqueous solution

Surfactant;

- fixing the abrasive tool impregnated with an aqueous surfactant solution on a shaking device that provides rotation of the tool with an angular speed of 0.3 - 0.5 s ^-1 ;

- convective drying of the abrasive tool by blowing it with a fan, supplying air heated to a temperature of 80 - 95 ° C, for 2.5 - 3 hours;

- visual inspection of the impregnated abrasive tool.

The process of impregnating an abrasive tool with a copolymer of ethyl acrylate, ethylene glycol dimethacrylic ester and methyl, which was dissolved in water in the amount of 10 grams per liter, is shown as an example (RF patent No. 2574182, IPC B24D 3/34. Bull. No. 4, 2016). An abrasive tool was dipped into the prepared surfactant aqueous solution at room temperature, using a 320 × 60 × 127 14A 25 K1 CM1 35 m / s grinding wheel GOST 2424-83 as the grinding wheel. A container with an aqueous solution of a surfactant and a grinding wheel inside it was placed in a magnetic pulse inductor, which creates an alternating magnetic field with a strength of H _V = 8 MA / m and a frequency of ƒ = 12 kHz. The exposure time of the high-frequency magnetic field to the impregnated circle was 5 minutes, after which the magnetic-pulse inductor was turned off and the abrasive tool was kept in an aqueous surfactant solution without exposure to a magnetic field for 2 minutes. It was found that the influence of a high-frequency magnetic field on an impregnated abrasive tool allows not only to reduce the time of impregnation of a surfactant abrasive tool due to the intensification of adhesive processes on the surface of abrasive grains, to facilitate the escape of air bubbles from pores and to improve the filling of the pore space of an abrasive tool with an aqueous surfactant solution, but also provide high contact strength of abrasive grains with a ceramic bond. As a result, chipping of abrasive grains from the tool during its operation is excluded. Exposure of the impregnated circle in an aqueous surfactant solution without exposure to a high-frequency magnetic field eliminates the possible magnetization of the abrasive grains of the tool, which are oxides or carbides of aluminum, titanium, tungsten and other metals. Convective drying of the impregnated tool was carried out using a fan supplying a tool rotating at an angular speed of 0.4 s ^-1 for 2.5 hours, air heated to a temperature of 90 ° C with continuous shaking of the impregnated tool through the use of an intermittent movement mechanism installed on the tool shaft (see "Theory of Mechanisms and Machines": Textbook for technical colleges / Ed. by K.V. Frolov. - M.: Higher School, 1987. - S. 343 - 442). Laboratory and production tests of an abrasive tool impregnated by the proposed method showed an increase in its resistance (time between dressings) by 6-8 times compared to standard tools without chipping abrasive grains while improving the quality of the machined surface of the part in terms of roughness parameters Rα and relative area of burns S.

To determine the optimal time for impregnating an abrasive tool with an aqueous surfactant solution in a high-frequency magnetic field t _n , holding an impregnated tool in an aqueous surfactant solution without a magnetic field t _e , magnetic field strength H _V and its frequency ƒ using the proposed method of impregnation, grinding wheels PP 320 were tested × 60 × 127 14А 25 K1 СМ1 35 m / s GOST 2424-83. A surfactant was a copolymer of ethyl acrylate, ethylene glycol dimethacrylic ester and methyl methacrylamide, which was dissolved in water in an amount of 10 grams per liter (RF patent No. 2574182, IPC B24D 3/34. Bull. No. 4, 2016). A magneto-pulsed electromagnetic oscillation inductor (coil) was used as a source of high-frequency magnetic oscillations, which was able to create a high-frequency magnetic field of intensity H _V = 6-15 MA / m and frequency ƒ = 8 - 18 kHz. Shaking the drying of a rotating abrasive tool was carried out by installing an intermittent movement mechanism on the tool shaft. Evaluation of the efficiency of impregnation of abrasive tools by the impregnation time t _n , the exposure time t _in , the magnetic field strength H _V and its frequency ƒ was carried out according to the wear rate of the circle J, which characterizes its durability (time between edits), roughness of the machined part surface Rα and relative area burns on it S. Cylindrical specimens of steel 35KhGSA with a diameter of 30 mm and a length of 329 mm were subjected to processing. Grinding was carried out on a circular grinding machine mod. 3M151 the following modes: cutting speed V = _KP 35 m / s, the speed being ground sample V _d = 0.5 m / s, the tool traverse S _np = 0.02 m / s, feeding infeed S _Bp = 0.01 mm / dv. stroke, the number of double strokes of the circle m = 3, without nursing. A 5% aqueous solution of emulsol Ukrinol-1 was used as a cutting fluid.

The test results are shown in table 1, the analysis of which shows that the best indicators of the wear rate of the circle J, the roughness of the machined surface of the part Rα and the relative area of the burns S are achieved when the abrasive tool is exposed to an alternating magnetic field of intensity H _V = 8-10 MA / m and frequency ƒ = 12-15 kHz for 4-6 minutes. followed by exposure to an aqueous solution of a surfactant without a magnetic field for 1-2 minutes

Comparative tests of the effectiveness of the proposed method for the impregnation of an abrasive tool and the known method of the prototype (see RF patent No. 2574182, IPC B24D 3/34. Bull. No. 4, 2016). The tests were carried out on abrasive wheels PP 320 × 60 × 127 14A 25 K1 SM1 35 m / s GOST 2424-83. Samples were grinded from steels 35 KHGSA, 20KHN2MA and KhN62 MVKY alloy with a diameter of 30 mm and a length of 320 mm, which had undergone preliminary turning and had an initial roughness Rα = 3.2 -6.3 μm. Grinding was carried out on a circular grinding machine mod. 3M151 in the following modes: cutting speed V _kp = 35 m / s, rotational speed of the grinding sample V _d = 0.5 m / s, longitudinal feed of the tool S _np = 0.02 m / s, feed _{rate of} cutting S _bp - 0.01 mm / dv. stroke, the number of double strokes of the circle m = 3, without nursing. A 5% aqueous solution of emulsol Ukrinol-1 was used as a cutting fluid.

Evaluation of the effectiveness of the proposed method for the impregnation of abrasive tools in comparison with the prototype (RF patent No. 2574182, IPC B24D 3/34. Bull. No. 4, 2016) was carried out according to the following indicators: the wear rate of the circle J, characterizing its durability (time between edits), roughness the machined surface of the part Ra and the relative area of burns on it S.

The test results are shown in table 2, from the analysis of which it follows that the application of the proposed method of impregnation of an abrasive tool in comparison with the prototype (RF patent No. 2574182, IPC B24D 3/34. Bull. No. 4, 2016) allows 1.3 - 1, 4 times to increase the resistance of grinding wheels (time between dressings) due to a decrease in the wear rate J due to the absence of abrasive grains from the bond, to reduce the roughness of the machined surface of the part by Rα by 20–25% and reduce the relative by 1.3–2.0 times its area S. Izhogov. At the same time, electricity costs associated with impregnation of abrasive wheels are reduced by 15 -20% and the total cost of impregnating one grinding wheel, depending on its size and technical characteristics, is reduced from 15.4 - 18.8 rubles. according to the prototype up to 10.3 - 12.5 rubles. by the proposed method of impregnation.

Claims (1)

A method of impregnating an abrasive tool, comprising impregnating the tool with an aqueous solution of surfactants at room temperature for 5-8 minutes and convective drying of the tool with rotation at a speed of 0.3-0.5 s ^-1 and a temperature of 80-95 ° C for 2.5-3.0 hours with continuous shaking, characterized in that the abrasive tool placed in an aqueous solution of surface-active substances is exposed to an alternating magnetic field of intensity H _V = 8-10 MA / m and frequency ƒ = 12-15 kHz for 4-6 minutes followed by holding in an aqueous solution of surfactants without a magnetic field for 1-2 minutes