RU2183313C2 - Active contactless method of measurement of polished surface roughness - Google Patents

Abstract

FIELD: machine-tool industry; monitoring surface roughness. SUBSTANCE: laser radiation scanner included in monitoring-and-transmitting unit has pulse generator, laser radiation diode, lens focusing system for radiating and receiving the beam reflected from surface being monitored, photodetector, power supply source, signal amplifier, modulator with transmitting antenna, logic unit of motion along zone of contact of tool with blank and micromotor with reduction gear; high-frequency signal radiated by transmitting antenna is received, amplified and recorded by receiving unit including receiving antenna, receiver, demodulator, filter separating useful component, signal amplifier, analog-to-digital converter and recorder. EFFECT: possibility of making proper estimation of height of microirregularities of surface layer of work; avoidance of rejects; maximum productivity of machining; extended field of application; enhanced reliability of measurement at any degree of roughness; reduced consumption of labor required for preparation for measurements. 6 dwg

Description

 The invention relates to the machine tool industry and relates to methods and devices for controlling the roughness of abrasive processing in the workplace.

 A known quantitative method for assessing surface roughness, which consists in measuring microroughness using a double microscope V.P. Linnik [1]. One part of the microscope provides illumination of the investigated surface, the second part - for observation and measurement of the surface profile.

 The disadvantage of this method is that the part, the surface roughness of which must be measured, must be removed from the machine and installed on the table of the device, that is, the method does not allow measurement directly on the machine, and especially during grinding, and this increases the time settings and measurements, reduces the performance of the control and makes it impossible to actively influence the measurement results on the processing process.

 The objective of the invention is to expand the scope and increase the reliability of measuring surface roughness during any abrasive treatment, as well as reducing the complexity in preparation for the measurement, while actively influencing the processing process, ending or continuing processing, depending on the measurement results.

 The problem is achieved by the proposed active non-contact method for measuring the roughness of a polished surface, in which the laser scanning device is directed to the section of the cutting zone, while the laser scanning device included in the control-transmitting element contains a pulse generator, a laser radiation diode, a lens focusing radiation system and receiving a beam reflected from the measured surface, a photodetector, a power source, a signal amplifier, a modulator with transmitting it with an antenna, a logical device for moving along the contact zone of the tool with the workpiece and a micromotor with a gearbox, in addition, the high-frequency signal emitted by the transmitting antenna is sensed, amplified and recorded by the receiving element, consisting of a receiving antenna, receiver, demodulator, filter emitting a useful component signal amplifier, analog-to-digital converter and registration device.

 The essence of the proposed method is illustrated by drawings in relation to flat grinding by the periphery of a circle with an axially offset cutting layer.

 Figure 1 shows a diagram of the measurement of the roughness of the polished surface of the proposed active non-contact method and the mounting of the scanning device for implementing the method on the casing of the grinding wheel with an axially offset cutting layer, side view; figure 2 - a view of figure 1; figure 3 is a view of B in figure 2; figure 4 is a block diagram of a scanning device that performs the functions of a control-transmitting element; figure 5 is a block diagram of a receiving and recording element; in FIG. 6 is a scan of the trace of the grinding wheel with an axially offset cutting layer on the work surface in FIG. 1 and 2.

 An active non-contact method for measuring the roughness of a polished surface is carried out using a device consisting of two elements.

 Mounted on the casing 1K of the grinding wheel 2Sh, the first control-transmitting element, made in the form of a scanning device, includes a pulse generator 11 (Fig. 4), a laser radiation diode 12, a lens focusing system 13 for transmitting and receiving a beam reflected from the measured surface Spare parts (Fig. 1), a highly sensitive photodetector 14 (Fig. 4), which is powered by a power source 15, a signal amplifier 16, a modulator 17 with a transmitting antenna, a logic device 18 for moving the carriage 6PC (Fig. 1), (which includes the above lined diode 12 (figure 4), the lens system 13 and the photodetector 14) and a micromotor 19, which moves the carriage 6PC (figure 1) along the guides 5H.

 The second element of the device - receiving and recording (Fig. 5) includes a receiving antenna 21, a receiver 22 receiving a high-frequency modulated signal, a demodulator 23 that detects a signal by isolating a low-frequency component, a filter 24 that selects a useful signal, a signal amplifier 25, analog-to-digital Converter 26; module 27 for communication with a recording device (it may be a personal computer (PC) with appropriate software).

 An active non-contact method for measuring the roughness of a polished surface is as follows.

 Before starting work on measuring roughness, a control - transmitting element (Fig. 1, 2) in the form of a scanning device 4C and a carriage 6PC mounted on guides 5H with the possibility of movement along the height of the circle is mounted on the casing 1K. To enable the scanning device to work, the 7PV trip switch is made in the form of a L-shaped lever. While the 7PV lever is in contact with the surface to be machined, the device is turned on and measurement is performed, when the grinding wheel leaves the contact zone with the workpiece, the device turns off when overrun.

 After installing the control-transmitting element, the abrasive wheel is corrected and balanced by known methods (not shown).

During processing, when the abrasive wheel is rotated and the table with the workpiece is moved longitudinally, the carriage 6PC moves along the guides 5H from position “a” to position “b”, covering the entire grinding zone B _about (see FIG. 3).

 In the next step of the table with the workpiece, the 6PC carriage from position “b” returns to position “a”, etc. The highly sensitive layers of photocell 14 are affected by a laser beam generated by a pulse generator 11 and a laser diode 12 and transmitted through the lens focusing radiation system 13 and receiving a beam reflected from the measured surface of the spare parts.

 Converted by photocells of laser radiation into an electrical analog signal is supplied from the photodetector 14 to the input of the matching amplifier 16.

 The amplified signal is converted by the modulator 17 into the high-frequency spectrum and sent by the transmitting antenna 20 to the receiving antenna 21 of the receiving-recording element (Fig. 5).

 The power of the control-transmitting element (Fig. 4) is carried out using an autonomous power source 15, mounted in a scanning device 4C, mounted on the casing 1K.

 The receiving antenna 21 (Fig. 5) and the receiver 22 receive a high-frequency signal of the roughness value and transmit it to a demodulator 23, which detects while highlighting the low-frequency part of the spectrum, the filter 24 eliminates spurious signals and selects the useful components of the signal, which is fed to the input of the amplifier 25, where amplified by voltage.

 The amplified roughness value signal is converted to digital form in an analog-to-digital converter 26. The digital roughness equivalent is recorded and processed by the registration and control device 27, which, when the surface roughness decreases and worsens due to blunting or greasing of the grinding wheel, or for other reasons, gives a warning signal to the operator or can send a control signal to the machine control system with the aim of dressing the grinding wheel or changing the modes of abrasive processing transition, such as nursing, etc.

 For final signal processing, a personal computer PC with appropriate software can be used.

 When using abrasive wheels with an axially offset cutting layer, which have zones of continuous and intermittent grinding (Fig.6) it is important to know the roughness in these areas.

 As a result, when processing with such a tool, when the length and position of the active section of the oscillating cutting zone, which depends on the angle of inclination of the axially displaced cutting layer, is not known, the proposed method measures the roughness at any point of the oscillating cutting zone and allows to determine the optimal angle of inclination of the axially displaced cutting layer.

Example. On a surface grinding machine mod. 3B722 polished flat surface of the part - rail. The material of the part is steel 45, hardened, hardness HRC 45. Characteristic of the circle PP 24A 16P SM2 7 K 1 A 35 m / s, the diameter of the new circle D _K = 450 mm, height B _K = 63 mm, the circle is set at an angle α = 4 ^o to a plane perpendicular to the longitudinal axis of the spindle.

Cutting modes: V _K = 34.3 m / s; n _k = 1450 rpm; V _d = 20 m / min (0.33 m / s); t = 0.02 mm / stroke on the reverse of the grinding headstock and lateral feed of the wheel S = S _d • В _о = 0.25 • 94.5 = 23.6 mm / stroke.

 The control and transmission element consists of a movable carriage, in which a laser radiation diode, a lens focusing system for emitting and receiving a beam and a photodetector are mounted, the carriage being able to axially move along the guides that are attached to the grinding wheel casing. The remaining parts of the control and transmitting element of the scanning device (pulse generator, power supply, signal amplifier, modulator with transmitting antenna, logical carriage moving device and micromotor) are mounted motionless on the casing.

 The receiving and recording element includes a receiver, a demodulator, a filter, an amplifier, an analog-to-digital converter, and a personal computer (PC) with the corresponding software.

The maximum roughness in the cutting zone was recorded R _a ^D = 0.63 μm at point D (in the center of the zone of continuous grinding, see figure 2, 6); at point E (in the center of the intermittent grinding zone) R _a ^E = 1 ... 1.25 microns; at the point Ж (in the center of the intermittent grinding zone) R _and ^Ж = 0.63 ... 0.57 microns.

 The proposed active non-contact method for measuring the roughness of a polished surface allows you to objectively assess the height of the microroughness of the surface layer of the workpiece, prevent defects, establish optimal conditions at the maximum productivity of abrasive processing, expand the scope and increase the reliability of measuring roughness in any abrasive and blade processing, and also reduce the complexity of preparation for measurement.

Sources of information
1. Danilevsky VV Technology of mechanical engineering. Ed. 3rd, rev. and add. Textbook for technical schools. M .: Higher school. 1972.P. 52-60.

Claims (1)

 An active non-contact method for measuring the roughness of a polished surface, in which the laser scanning device is directed to a section of the cutting zone, characterized in that the laser scanning device included in the control-transmitting element comprises a pulse generator, a laser radiation diode, a lens focusing radiation and reception system beam reflected from the measured surface, photodetector, power source, signal amplifier, modulator with transmitting antenna, logic device movements along the contact area of the tool with the workpiece and a micromotor with a gearbox, while the high-frequency signal emitted by the transmitting antenna is sensed, amplified, and recorded by the receiving element, which consists of a receiving antenna, receiver, demodulator, filter that selects the useful component, signal amplifier, analog-to-digital converter and registration device.

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