SU1306649A1 - Method of determining optimum speed of cutting - Google Patents

Abstract

. The invention relates to a machine tool industry, in particular to methods for determining the optimal cutting speed. The invention improves the accuracy and reduces the laboriousness of experimentally finding the cutting speed optimal for cutting forces for non-rigid tools by fixing, on the basis of a comparative analysis of the acoustic spectrum and frequency of the location of growth particles on the cutting surface, the speed at which the growth is most stable. Acoustic spectrum is obtained: using a piezoelectric vibrating receiver with recording on a tape recorder and an audio frequency spectrometer, a signal about the breakdown of the build-up at the moment of the appearance of its particle on the cutting surface is selected. This signal is used to assess the stability of a build-up over the entire range of build-up rates. 1 tab. from 9 (L: about 35; about

Description

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The invention relates to a machine tool stitch, in particular, to methods for determining the optimum cutting mode during machining.

The purpose of the invention is to improve the accuracy, reduce the laboriousness of determining the optimal cutting speed and expand the scope of application of the method by optimizing the signal about the breakdown of growth particles on the cutting surface.

The method is implemented as follows.

A signal from which a piezoelectric vibro-receiver is fed to a piece being processed, for example by a boring cutter, is fed through a cathode repeater and amplifier to a tape recorder. Analysis of the acoustic spectrum recorded on a magnetic tape is performed using a spectrometer.

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sound frequencies. Typically, the number of growth breakdowns on a base of 10 mm by cutting is in the range of 2-20, hence for the selected cutting speed V m / s, the frequency of breakdowns of growth is 200-2000 V. By selecting the cutting speed at which the build-up is formed, and calculating the frequency range of growth breakdown , using a spectrometer in this range, a signal is selected that corresponds to the moment of breaking the growth by comparing the location of the maxima and minima in the spectrogram and a part of the growth on the cutting surface. For a better reference to the cutting time before the occurrence of the build-up damage being considered, the bore of the billet is bored. longitudinal groove or instantly interrupt the cutting process using a special device of known construction. After detecting the signal of failure and establishing its shape, a boring is performed in the entire range of growth rates with a measurement of the corresponding breakdown growth frequencies, fixing the speed at which the signal frequency is minimal, and taking it as the optimal one. The optimal cutting speed corresponds to lower vibrations and cutting forces, allowing the tool to work up to large values of wear and c. the greatest resistance. For example, a boring tool made of high-speed steel P18 when machining steel blanks, 45 with a diameter of 40 mm and a rotational speed of 200 1 / min, hearth: 06649 2

whose 0,2-im / ob and depth of cutting 1 mm showed durability 84 min, and at a rotational speed of 315 1 / min - only 7 min, in the first case, the speed of the re-5 undertake is optimal according to the growth condition, and in the second - corresponds to the greatest cutting force, and processing was carried out without growth.

The method can be applied in the JO cutting process without ei o stopping, i.e. in the conditions of automated production. The loose particles of growth on the cutting surface are clearly visible and do not depend on the elemental structure of the chips. The frequency of breakdown of growth particles by the acoustic method is determined with high accuracy, and the scatter of the obtained values at the same cutting speed does not exceed 20%.

The method is tested when drilling steel with 45 drills with a diameter of 20 mm made of high-speed steel P18 with a feed of 0.25 mm / rev. The test results are shown in the table.

The data obtained confirm the optimal cutting speed of 0.4 m / s, at which the wear rate is minimal.

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Note: Drilling length 3 diameters, work without cooling, drills with a point of the transverse edge.

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acquisitions

The method of determining the optimal cutting speed, in which ax3 13066494

There is a change in the rate of cut-growth, which is determined by sony in a predetermined range and the simultaneous delivery of the components Bii6poai ;;; the vibroacoustic signal and particles of growth are recorded simultaneously.

the signal emitted by the cutting area, the cutting surface at the same moot, because, c, the time cops, determine the frequency by the target of increasing the accuracy, reducing the divided signal, and taking the speed, and

application, from the vibroacoustic frequency of the selected signal

the signal makes the break signal n-minimal.

Claims (2)

The method of determining the optimal cutting speed at which wasp 3 1306649 make a change in cutting speed in a given range and simultaneously register a vibroacoustic signal emitted by the cutting zone, characterized in that, in order to increase accuracy, reduce labor intensity and expand the scope, a growth failure signal is extracted from the vibroacoustic signal, which is determined by comparison components of the vibroacoustic signal and growth particles on the cutting surface at the same time, determine the frequency of the selected signal, and as the optimal the rate at which the selected frequency signal is minimal.