RU2276004C1 - Grinding method - Google Patents

Abstract

FIELD: machine engineering, possibly operations for grinding blanks of metals and alloys.

SUBSTANCE: method comprises steps of imparting to blank ultrasonic oscillations for releasing technological residual stresses in its surface layer. Frequency modulated ultrasonic oscillations are imparted continuously during grinding cycle through worked surface of blank in normal direction.

EFFECT: enhanced efficiency of grinding process.

Description

The invention relates to mechanical engineering, for the processing of metals by cutting and can be used when grinding workpieces from various materials.

The invention is aimed at solving the problem of improving the grinding efficiency and improving the quality of polished parts by reducing the magnitude and depth of propagation of tensile residual stresses in their surface layer.

It is known that in the surface layer of polished parts, as a rule, tensile technological residual stresses are formed that adversely affect the operational characteristics of the parts (see Matalin A.A. Engineering technology: Textbook for engineering universities. - L.: Engineering, 1985. - 496 from.).

Widely known are methods for removing technological residual stresses, such as natural and artificial aging, low-temperature tempering (see Gulyaev A.P. Metallurgy. Textbook for high schools. M .: Metallurgy, 1986. - 544 p.). The disadvantage of the described methods is that their implementation is associated with significant material, time and energy costs.

The closest in technical essence to the claimed invention is the method of ultrasonic stabilization of residual stresses selected as a prototype (see Babenko MG Improving the technology for ensuring dimensional accuracy of precision parts such as bearing rings based on the use of ultrasonic stabilization of internal stresses. Author's abstract. Dis .... Candidate of Technical Sciences: 05.02.08 / Saratov State Technical University - Saratov, 2002. - 16 pp.), in which, after grinding the details, ultrasound is reported through the polished surface f fluctuation certain amplitude and frequency.

An essential feature of the prototype, common to it and the proposed method is the communication of the ultrasonic vibrations part, the energy of which is absorbed by the dislocations of the surface layer of the part and converted into the displacement energy of these dislocations, causing the development of intragrain deformations, which contributes to plastic shears that reduce residual stresses.

The disadvantage of the prototype is to increase the processing time by including in it the time for ultrasonic stabilization of residual stresses. In addition, the disadvantage of the prototype is the involvement of a relatively small number of dislocations in the process of dislocation absorption of ultrasound energy, the sizes of which lie in a narrow range, since the frequency dependence of the dislocation absorption is resonant in nature, and the intrinsic resonance frequency of the dislocation is determined by the length of the dislocation segment (see Ultrasound. Small Encyclopedia / Under the general editorship of I.P. Golyamina. - M .: Soviet Encyclopedia, 1979. - 400 p.). This disadvantage is due to the fact that the prototype used ultrasonic vibrations of a certain fixed frequency. As a result, the efficiency of removing technological residual stresses is small.

EFFECT: increased efficiency of grinding operations due to removal of technological residual stresses in the surface layer of a grinded workpiece and involvement of a larger number of dislocations in the process of dislocation absorption of ultrasound energy. This will also increase the grinding performance while ensuring a given level of technological residual stresses in the surface layer of polished parts.

To achieve a technical result, the claimed invention contains the following general, expressed by certain concepts, essential features, the totality of which is aimed at solving only one problem associated with the technical result. The polished parts report ultrasonic vibrations. Distinctive features of the claimed invention in relation to the prototype are:

1) a continuous message in the grinding cycle of ultrasonic vibrations to the workpiece through the machined surface in the normal direction, which ensures the combination of grinding and ultrasonic removal of residual stresses;

2) a frequency-modulated form of ultrasonic vibrations communicated to the part, which helps to intensify the process of dislocation absorption of ultrasound energy and increase the efficiency of removing technological residual stresses in the surface layer of polished parts.

To communicate the polished part of ultrasonic vibrations of a frequency-modulated shape, an electric signal, modulated in frequency, is required, which can be obtained using a special generator.

Between the hallmark and the technical result, there is the following causal relationship. Communication to the workpiece of frequency-modulated oscillations contributes to the intensification of the conversion of ultrasound energy into dislocation displacement energy, which contributes to plastic shifts that reduce residual stresses. The combination of grinding and ultrasonic removal of residual stresses reduces the processing time.

Claims (1)

A grinding method, including communicating ultrasonic vibrations to a workpiece to remove technological residual stresses in its surface layer, characterized in that the ultrasonic vibrations are continuously transmitted through a grinding cycle through the workpiece surface to be processed in the normal direction, while the ultrasonic vibrations report a frequency-modulated shape.