Device for measuring the roughness and waviness of the surface at fixed values of base length

 

(57) Abstract:

The invention relates to measuring technique and is intended to control the production of regulated parameters of roughness and waviness and can be used in metallurgical, machine-building, electronic, optical, printing industry, in aircraft construction. The device contains a light source, collimating lens, a translucent plate, a sensor for registration of specularly reflected light and diffusely reflected radiation, a capacitor consisting of two lenses between which are located the light source and the inner hole of radius aiin a sensor for registration of diffusely reflected radiation, the latter is in the form of a ring with internal aiand outside of ajradii from the condenser acts as a screen. Cylindrical absorber are removable, there are a collimating lens and a photodetector for registration of diffusely reflected radiation. Radii aiand ajprovide measurement of roughness parameters for a given baseline length. In addition, the device is equipped with a sink and a lens, a focusing mirror-tregistration specularly reflected radiation and the center of the translucent plate. The signal processing unit contains two amplifiers, adder and two divider. 2 Il.

The invention relates to techniques of measurement and is designed to control the production of products with regulated parameters of roughness and waviness and can be used in metallurgical, machine-building, electronic, optical, printing industry, in aircraft, in coating technologies.

Known profilometer containing the corner, the sensor vertical movement of the needle block horizontal movement of the needle with gauge, frequency filters signals from the sensor vertical movement of the needle and the signal processing unit supplied with the frequency of the filter and sensor horizontal movement [1]

Each filter in the known device filters the signal to the stepper parameters in accordance with a given base length li8; 25; 0,8; 0,25; 0,08 mm Signal passing through this filter corresponds to the roughness parameters at a fixed reference length. The signal that is clipped when this filter is related to the parameters of waviness at this fixed reference length. In addition, the profilometer measurement of surface profile assiago radius measures the roughness of the stepper settings, larger thanjrjwhere TOjcoefficient taking into account the proportion of the contact tip with the surface, which varies in the range from 1 to 0.9 with increasing rj.

The disadvantages of this monitor is that it is based on contact-needle method of measuring the surface profile, which leads to the impossibility of measuring the roughness and waviness of light plastic materials; inability to measure roughness parameters in high-speed machining components.

In addition, the measurement process on the Profiler requires laboratory conditions (no vibration), and the known device are measured only relevant surface characteristics, i.e., two-dimensional characteristics, not topographic, i.e., three-dimensional characteristics.

The closest technical solution of the invention is a device for controlling the roughness and waviness of the surface containing are located on the same axis as the light source, the translucent plate and a collimating lens, a photodetector, is designed to detect specularly reflected radiation, a photodetector, is designed to detect diffusely reflected radiation, and the processing unit signals the treatment, which depends on the long-wavelength part of the spatial spectrum of the surface profile (waviness) and shortwave (roughness), which leads to a sharp decrease in the accuracy of measurement of roughness and waviness and the mismatch between the characteristics of roughness, measured by the optical method and the method of contact profilometry.

The basis of the invention is to devise a structure of the optical device, which would provide the allocation information on the long-wavelength component of the profile (waviness) and short-wave component of the profile (roughness) by creating a spatial optical filters with well-defined borders bandwidth determined by the values of the base length. This improves the measurement accuracy and to extend the functionality of the device.

This is solved by the fact that the proposed device for measuring the roughness and waviness of the surface at fixed values of base length equipped with a condenser, a cylindrical absorber, an additional absorber and lens used for focusing the specularly reflected radiation, the condenser is designed as two Steen, cylindrical absorber is made removable, installed in the condenser and in the course of radiation on one axis with the condenser installed sensor, designed to detect diffusely reflected radiation, and a collimating lens. The photodetector, is designed to detect diffusely reflected radiation, made in the form of a ring with one light-sensitive surface facing the collimating lens. Additional absorber and the lens is designed to focus specularly reflected radiation, installed on opposite sides of the translucent plate coaxially to the photodetector, intended for registration of specularly reflected radiation, so that their axis crosses the axis of the condenser in the center of the translucent plate. The signal processing unit consists of two amplifiers, adder and two dividers.

The photodetector, is designed to detect diffusely reflected radiation, is connected to the input of one amplifier and the photodetector, is designed to detect specularly reflected radiation to the input of another amplifier. The outputs of the amplifiers are connected to the inputs of the dividers and the inputs of the adder, the output of which is connected to the inputs deleteLater hole ring, the inner radius of which for each removable cylindrical absorber is chosen from the condition:

ai=

where the wavelength of the incident radiation;

F focal length collimating lens;

lithe value of the base length.

In Fig. 1 shows a device for measuring the roughness and waviness at fixed values of the base length, the section of Fig. 2 characteristics of spatial filters for measurement of roughness and waviness, where lithe value of the base length, And corresponds to the value of l 0.08 mm; 0.25 mm; 0.8 mm; D 2,5 mm; 8 mm; the area to the left of the lines corresponds to the roughness, the right waviness at fixed values of the base length.

Device for measuring roughness and waviness at fixed values of base length contains the light source 1 (Fig. 1), the condenser is made in the form of two coaxially mounted along the radiation from the light source lenses 2 and 3, between which is placed a translucent plate 4.

The device is equipped with a removable cylindrical absorber 5, which is mounted by means of a thread for the condenser and in the course of radiation on one axis with the condenser installed photopie the receiver 6 is made in the form of a ring with a single photosensitive surface 8, facing the collimating lens 7. Moreover, the collimating lens 7 and the condenser lens 3 is set relative to each other so that their foci coincide in the center of the hole 9 of the ring 6, the inner radius aifor each removable cylindrical absorber 5 is chosen from the condition:

ai< / BR>
where the wavelength of the incident radiation;

F focal length collimating lens;

lithe value of the base length.

Thus, the number of removable cylindrical absorber 5 in the device is defined by a set of basic length lithat it is necessary to define the parameters of roughness and waviness.

The device comprises a sensor 10, is designed to detect specularly reflected radiation, an additional absorber 11, designed to absorb radiation of the light source 1 and the lens 12, which is designed to focus specularly reflected radiation. Additional absorber 11 and the lens 12 mounted on opposite sides of the translucent plate 4 coaxially to the sensor 10 so that the axis intersects the axis of the condenser in the center of the translucent plate 4.

The signal processing unit is made in the form of Duo reflected radiation, connected to the input of the amplifier 13 and the photodetector 10, is designed to detect specularly reflected radiation, is connected to the input of the amplifier 14, the outputs of the amplifiers 13 and 14 are connected respectively to the inputs of the dividers 16 and 17 and the inputs of the adder 15.

The output of the adder 15 is connected to the inputs of the dividers 16 and 17. And the output of the divider 16 is proportional to the roughness parameters of the investigated surface 18, and the testimony of the divider 17 parameters waviness of the same surface 18.

The device operates as follows.

The radiation from the light source 1 passes through the lenses 2 and 3 of the condenser through the translucent plate 4 and is focused into the center hole 9 of the ring 6. Part of the radiation reflected by a translucent plate 4, is absorbed by the additional absorber 11; and the other part of the radiation passing through the opening 9 of the ring 6, spatially filtered, i.e., all the distortions of the wave front with a periodicity of less liare clipped, where lithe value of fixed baseline length. This spatial-filtered radiation passing through the collimating lens 7, falls on the analyzed surface 18 and reflected from it, again passes through the collimating lens 7.This removable cylindrical absorbers 5 are different from each other, the inner radius of the hole 9 of the ring 6, which is determined from the conditions: aiF/li. This allows to measure the roughness and waviness at fixed values of the base length li.

Signals from the photodetector 6, intended for registration of diffusely reflected radiation amplified by the amplifier 13, is coming to the adder 15 and the divider 16, and the signals of the m 14, come to the adder 15 and the divider 17.

The testimony of the divider 16 is equal to the ratio of diffusely reflected radiation to all of the reflected radiation that in the inventive device characterizes the roughness of the sample surface 18 with stepper parameters from the Kjrjto li.

The testimony of the divider 17 is equal to the ratio of specularly reflected radiation to all of the reflected radiation that in the inventive device is characterized waviness of the surface being examined 18 stepper parameters large li.

The device allows for simultaneous measurement of parameters of roughness and waviness at fixed values of the base length lithat extends its functionality, improves accuracy and makes the results are identical to results obtained with profilometers.

DEVICE FOR MEASURING the ROUGHNESS AND WAVINESS of the SURFACE AT FIXED VALUES of the BASE LENGTH, containing situated on the same axis as the light source, the translucent plate and a collimating lens, a photodetector, is designed to detect specularly reflected light, the photodetector designed to register bieno the condenser, cylindrical absorber, an additional absorber and lens used for focusing the specularly reflected radiation, the condenser is made in the form of two coaxially mounted along the radiation from the light source lens, which is placed between the translucent plate, a cylindrical absorber is made removable, installed in the condenser and in the course of radiation on one axis with the condenser installed sensor, designed to detect diffusely reflected radiation, and a collimating lens, a photodetector, is designed to detect diffusely reflected radiation, made in the form of a ring with one light-sensitive surface facing the collimating lens, an additional absorber and the lens, designed to focus specularly reflected radiation, installed on opposite sides of the translucent plate in alignment with the photodetector, intended for registration of specularly reflected radiation, so that their axis crosses the axis of the condenser in the center of the translucent plate, the signal processing unit consists of two amplifiers, adder and two dividers, a sensor, designed to detect diffuse otrazhennogo radiation, with the input of another amplifier, the outputs of the amplifiers are connected to the inputs of the dividers and the inputs of the adder, the output of which is connected to the inputs of the dividers, and the collimating lens and the condenser lens has one relative to the other so that their foci coincide in the center hole of the ring inner radius aifor each removable cylindrical absorber choose the conditions

< / BR>
where the wavelength of the incident radiation;

F focal length collimating lens;

lithe value of the base length.

 

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