SU1296370A1 - Method for diagnostics of members in rest-chuck-tool-work closed dynamic system - Google Patents

Abstract

The invention relates to a machine tool industry and the challenge is to ensure the possibility of assessing the dynamic state of the elements of the AIDS system. The purpose of the invention is to reduce the labor intensity and speed up diagnostics nroness. The method involves obtaining a spectrum of relative oscillations between the im- structure and the part during the cutting process, detecting the dominant frequencies, determining the natural oscillation frequencies of the elements of the AIDS system and comparing them with the dominant frequencies. In this case, the spectrum of relative oscillations is obtained by measuring the noBepxHocYn circular pattern of the processed part in the transverse section. 2 Il. SS (L to from 05 to

Description

one

1296370

The invention relates to metal cutting, namely to blade processing of parts such as rotation bodies.

The purpose of the invention is to reduce the complexity and speed up the diagnostic process by analyzing the deviations of the shape of the machined parts using the methods of the spectral theory of accuracy.

FIG. Figure 1 shows the spectral density of relative oscillations obtained by recording the error of the machined surface of the part in cross section in the case when the element defining the dominant form of oscillations of the AIDS system is a belt pulley during the processing of an internal combustion engine liner on a special mod. ME 270SO (curve 1); the same, by recording the relative oscillations between the cutter and the workpiece using a relative oscillation sensor (curve 2); spectral 10

15

elements of the SIID- system (caliper - 100 Hz, spindle - 130 Hz, reztseblok - 236 Hz, rotational speed from imbalance of the engine 25 Hz) and comparison with the dominant frequency allowed us to identify the belt pulley on the engine as a faulty element. The level of oscillations at this frequency was also evaluated. For this, a narrow-band process was used at the output of a bandpass filter with a central frequency of 25 Hz. The narrowband envelope process may be considered as a slowly varying function of time. Then, as an estimate of the oscillation amplitude, one can take the expectation

the ordinate of this envelope

BUT

where (is the estimate of the dispersion of the narrowband random process considered. In our case, b 26, then A 261, 25 32.5 microns. After replacing the pulley, the vibration was obtained by recording the machined surface error of the part in cross section after changing the pulley and no resonance, other elements of the system AIDS (curve 3); in Fig. 2, the square curve of the coherence function (3) between the spectral densities shown in Fig. 1 (curves 1 and 2).

25

on the density of relative fluctuations, 20 stopped. Spectral density

relative oscillations are shown in fig. 1 (curve 3). From the spectrum it can be seen that there are no elements in the system that determine the dominant form of oscillations of the AIDS system. Due to this, the cutting tool chipping stopped and the tool life distribution became close to the normal distribution law. In the process of obtaining an oscillation spectrum according to a known method, the relative oscillations were recorded using an arched contact sensor, and this information was also processed using this program.

As a result of processing the obtained information, two spectral densities of relative oscillations were obtained (Fig. 1, curves 1 and 2).

In FIG. 2 that the square of the coherence function between these spectra is close to unity at a frequency of 25 Hz.

Thus, the proposed method makes it possible to quickly diagnose the state of the elements of the AIDS system under production conditions, increase the reliability of the equipment and the tool and reduce downtime.

40

With the help of this method, the diagnostics of the elements of the closed system of zo-AIDS were carried out when processing the liner of an internal combustion engine on a lathe mod. ME270SO. The material to be processed is special cast iron, HB200 ... 240. The processing material is cutting ceramics of the VOK-60 brand. Modes of cutting: V 146 m / min (p 315 r / min); S 0.3 mm / rev, mm. During processing, vibrations were observed, which led to frequent chipping of the cutting tool. The distribution of tool life in this case was subject to an exponential law. To establish the element that determines the dominant mode of oscillations of the AIDS system, in the cross section of the treated sleeve was recorded the error in the shape of the surface on the mode meter. 290 with 45 magnification 500 and filter 6 (15-150 waves / / about). The signal was recorded on an oscillographic mod-on paper. HI 15 in the form of oscillograms. Recorded waveform with a mode converter. POF was digitized and recorded on a magnetic tape on a mod instrument. EC9002. From a magnetic tape, data was entered into a computer (IVC-2) and processed using a special program for spectral analysis of random processes.

Analysis of natural vibration frequencies (obtained with a vibrometer) of the fundamentals50

Claims (1)

Invention Formula A method for diagnosing the elements of a closed dynamic AIDS system, including obtaining a parameter characterizing the relative oscillations between the tool and the workpiece, detecting the dominant frequencies, relative oscillations, determining the natural oscillation frequencies of the elements of the AIDS system, comparing them with the dominant frequencies, characterized in that to reduce the complexity and speed up the diagnostic process, after processing the workpiece, a circle is recorded elements of the SIID- system (caliper - 100 Hz, spindle - 130 Hz, reztseblok - 236 Hz, rotational speed from imbalance of the engine 25 Hz) and comparison with the dominant frequency allowed us to identify the belt pulley on the engine as a faulty element. The level of oscillations at this frequency was also evaluated. For this, a narrow-band process was used at the output of a bandpass filter with a central frequency of 25 Hz. The narrowband envelope process may be considered as a slowly varying function of time. Then, as an estimate of the oscillation amplitude, one can take the expectation the ordinate of this envelope BUT where (is the estimate of the dispersion of the considered narrow-band random process. In our case, b 26, then A 261, 25 32.5 µm. After replacing the pulley, the vibration stopped. Spectral density Invention Formula A method for diagnosing the elements of a closed dynamic AIDS system, including obtaining a parameter characterizing the relative oscillations between the tool and the workpiece, detecting the dominant frequencies, relative oscillations, determining the natural oscillation frequencies of the elements of the AIDS system, comparing them with the dominant frequencies, characterized by in order to reduce the laboriousness and speed up the diagnostic process, after processing the workpiece, a circular diagram of its cross-section is recorded, according to which ayut as para-t swarm derivative calculation of the spectral density meter characterizing relative Ko NOSTA transverse cross section shape deviations oscillations between the tool and the workpiece. / 2