CN115183657B - Device and method for measuring surface shape error of flat plate in non-contact mode by combining level gauge with air-bearing bridge plate - Google Patents

Abstract

The invention relates to a device and method for non-contact measurement of the surface shape of a flat plate by combining a level with an air-floating bridge plate, wherein an adjustable air-floating bridge plate is used as an auxiliary tool of the level to measure the surface shape error of the flat plate; firstly, a fixed air pressure is input to the air-floating bridge plate, so that the working surface of the air-floating module outputs a stable high-pressure airflow floating on the measured surface; then a ruler positioning device is used to drive the air-floating bridge plate to move linearly on the measured surface to realize non-contact measurement; finally, the reading value of the level on the bridge plate is recorded to analyze the surface shape error of the measured surface; during the implementation of the method of the invention, the measuring axis can always be moved along the reference mark line, and has good overlap and span positioning accuracy; the air-floating surface has no contact and friction with the measured surface in the working state, which can effectively protect the surface from collision and wear, greatly reduce the fatigue strength of the operator, and reduce the influence of environmental factors on the measurement results.

Description

Device and method for non-contact measurement of flat plate surface error by combining level with air-floating bridge plate

Technical Field

The invention belongs to the field of detection, and in particular relates to a device and method for contactlessly measuring the surface shape error of a flat plate by combining a level with an air-floating bridge plate.

Background Art

Marble slabs have excellent surface accuracy and are often used as reference surfaces for precision testing and adjustment. To ensure the accuracy of testing and adjustment, the surface accuracy of the slab needs to be calibrated before use. There are many methods for measuring the flatness of a slab, among which the level pitch method has the characteristics of simple structure and high accuracy and has been widely used in the evaluation of slab plane errors. This detection method is to divide the surface of the slab to be measured into sections, fix it on the bridge board with a precision level, place the bridge board on the marked line of the measured surface in sequence, and obtain the front and rear span inclination angle of the level through the bridge board measuring surface or the generatrix contacting the measured surface. After data processing, the flatness error is evaluated by diagonal lines, three far points and other methods. The shortcomings of the above methods mainly include the following points:

(1) The span surface or generatrix of the bridge plate is prone to collision and wear when in contact with the measured surface, which reduces its accuracy and affects the accuracy of flatness measurement;

(2) In order to ensure the accuracy and repeatability of the flatness test data of the plate, the personnel need to place the bridge plate on the surface to be tested for repeated measurements many times, so the fatigue intensity of the test personnel is relatively high, and the measurement results are easily affected by factors such as ambient temperature and vibration, which introduces measurement errors;

(3) When personnel place bridge deck spans, the overlap is often inconsistent and the dispersion is large, resulting in poor span positioning accuracy and repeatability, which directly affects the surface fitting accuracy.

Summary of the invention

The purpose of the method of the present invention is to solve the shortcomings of the above-mentioned measurement method, and to provide a device and method for non-contact measurement of the surface shape error of a flat plate by combining a level with an air-floating bridge plate. The present invention adopts an air-floating bridge plate as the measurement span of the level; the air-floating bridge plate can adjust the air-floating surface measurement span according to the measured section, and by inputting high-pressure airflow to the air-floating module, the air-floating block outputs a stable airflow, and forms a gap layer of uniform size between the measured surfaces, and measures the gap layer formed between the air-floating surface and the measured surface at both ends, and uses a ruler positioning device to drive the air-floating bridge plate to float on the measured surface, and moves in a straight line along the reference mark to achieve non-contact measurement.

To achieve the above object, the present invention provides the following technical solutions:

A device for non-contact measurement of flat plate surface shape error by combining a level with an air-floating bridge plate, the device comprising: an air-floating bridge plate and a ruler positioning device;

The air-floating bridge plate includes a bridge plate frame, an air-floating module and a connecting seat; the bridge plate frame includes a fixed stopper, an adjustment mechanism, a fixed guide rail, a fixed groove and a base plate; the air-floating module includes a fixed air-floating block, an adjustable air-floating block, a connecting seat and a locking screw;

In the bridge plate frame: the fixed block is used to fix the level, the adjustment mechanism is used to fine-tune the posture of the level, the fixed guide rail is installed at the center of the base plate as a sliding guide rail of the connecting seat, and the two fixed grooves are respectively installed on both sides of the fixed guide rail for sliding support and locking of the connecting seat. The base plate is used as a reference surface of the air-floating bridge plate for the assembly and installation of the components of the device and provides a suitable load force;

In the air flotation module: the fixed air flotation block and the adjustable air flotation block are used to output a stable high-pressure airflow on the surface of the measured flat plate; the lower end surface of the connecting seat is connected to the adjustable air flotation block, and the connecting seat is installed on the fixed guide rail and the fixed groove to adjust the air flotation span; the locking screw is used to lock and fix the connecting seat after the span is adjusted;

The ruler positioning device includes a ruler, a fixed block, and a driving block. When in use, the lower surface of the ruler body is close to the surface of the measured flat plate, the upper surface of the ruler is longitudinally provided with standard scale lines for positioning when adjusting the span, and the upper surface of the ruler is transversely provided with a center line as a reference line. The two fixed blocks are installed at both ends of the ruler body to fix the ruler, the lower end of the driving block is connected to the ruler, and the upper end is connected to the bottom of the air-floating bridge plate through a mechanical positioning groove. The driving block controls the air-floating bridge plate to move linearly. When the air-floating bridge plate moves linearly, only traction is applied to the air-floating bridge plate along the measuring direction, and no force is applied in other directions.

The present invention also provides another technical solution:

A method for non-contact measurement of a flat plate surface error using the device, the method comprising the following steps:

Step 1: Select the air flotation block;

The shape and size of the air flotation block are determined according to the shape and size of the plate to be tested;

Step 2: Assemble the air floating bridge board;

Step 3: Calibrate the air floating bridge plate;

By calibrating that the inner lateral opposite surfaces of the fixed air floating block and the adjustable air floating block are parallel, the outer longitudinal opposite surfaces are parallel, and the air floating blocks are coplanar;

Step 4: Assemble the ruler positioning device;

Step 5: Use the air floating bridge plate to measure the flat surface shape;

First, the surface of the measured flat plate is segmented according to the pitch method, and then the measuring span of the air-floating bridge plate is adjusted according to the pitch line segments. The air-floating bridge plate is driven in turn by the ruler positioning device to perform non-contact measurement along the diagonal, long line and short line. Finally, the level instrument detection data is obtained and the flatness error is calculated and analyzed according to the evaluation rules.

Furthermore, in step 1, when the flat plate to be measured is a rectangular flat plate, a rectangular air flotation block is selected, and when the flat plate to be measured is a circular ring-shaped flat plate, an arc-shaped air flotation block is selected.

Furthermore, the assembly and connection method of the air-floating bridge plate is as follows: the fixed stop block is connected to the upper end surface of the adjusting mechanism and installed on the front upper surface of the substrate, the fixed guide rail is installed in the central area of the rear upper surface of the substrate, the upper end center of the connecting seat is installed on the fixed guide rail, and the two side support plates of the connecting seat are respectively installed in the center of the two fixed grooves, and the lower end of the connecting seat is connected to the upper end of the adjustable air-floating block through the substrate and three locking screws are installed on the upper end of the connecting seat, and the fixed air-floating block is installed at the front lower end of the substrate to complete the combined connection.

Furthermore, there are two fixed air floating blocks and two adjustable air floating blocks respectively.

Furthermore, the assembly connection method of the ruler positioning device is: the lower surface of the ruler is pressed against the surface of the measured flat plate, fixing blocks are installed on both sides of the ruler body, the upper end is installed and connected to the lower end of the driving block, and the upper end of the driving block is connected to the bottom of the air-floating bridge plate to complete the combined connection.

The advantages of the present invention compared with the prior art are:

(1) In the present invention, the air-floating bridge plate can float on the measured surface to achieve non-contact measurement, effectively protecting the measuring surface and the measured surface from being bumped and scratched, and reducing the fatigue intensity of the test personnel and the measurement error caused by environmental factors;

(2) The present invention is convenient and stable to operate, and has high detection efficiency.

(3) The present invention drives the bridge plate to move through the scale positioning device, has good span placement positioning accuracy and repeatability, and improves measurement accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a process of non-contact measurement of flat plate surface error by a level combined with an air-floating bridge plate according to the present invention;

Fig. 2 is a schematic diagram of a device for non-contact measurement of flat surface shape error of a level combined with an air-floating bridge plate of the present invention; wherein: 1 is a bridge plate frame, 2 is an air-floating module, 3 is a scale positioning device, 4 is a digital level; 110 is a fixed stopper, 120 is an adjustment mechanism, 130 is a fixed guide rail, 140 is a fixed groove, 150 is a base plate; 210 is a fixed air-floating block, 220 is an adjustable air-floating block, 230 is a connecting seat, 240 is a locking screw; 310 is a scale, 320 is a fixed block, and 330 is a driving block;

FIG3 is a schematic diagram of measuring the surface error of the air-floating bridge plate according to the flat plate inspection specification by using the pitch method.

DETAILED DESCRIPTION

In order to facilitate a better understanding of the method of the present invention, each link involved in the present invention is described in detail below by means of drawings and implementation examples.

Implementation process: In this example, the method of the present invention is used to detect the surface shape error of a 2m×1.5m marble slab for detailed description.

The implementation steps are as follows:

Step 1: Choose the air flotation block

According to the size and shape of the plate, four rectangular porous medium flotation blocks with an appearance of 30mm×15mm were selected. The size of each flotation working surface is 25mm×10mm, the flatness of the working surface is 0.2μm, and the flotation height under load is 5μm.

Step 2: Assembly of air floating bridge board

As shown in FIG2 , the air-floating bridge plate includes two major parts: a bridge plate frame 1 and an air-floating module 2; the bridge plate frame 1 includes a fixed stopper 110, an adjustment mechanism 120, a fixed guide rail 130, a fixed groove 140, and a base plate 150; the air-floating module 2 includes a fixed air-floating block 210, an adjustable air-floating block 220, a connecting seat 230, and a locking screw 240;

(1) In the bridge plate frame 1: the fixed block 110 is used to fix the level, the adjustment mechanism 120 is used to fine-tune the posture of the level, the fixed guide rail 130 is installed at the center of the base plate 150 as a sliding guide rail for the connecting seat 230, and the fixed grooves 140 are installed at two locations on both sides of the fixed guide rail for sliding support and locking of the connecting seat 230. The base plate 150 serves as a reference surface for the air-floating bridge plate, which is used for the combined installation of all components and provides a suitable load force;

(2) In the air flotation module 2: two fixed air flotation blocks 210 and two adjustable air flotation blocks 220 are respectively connected to the bottom of the front and rear sections of the substrate 150 to output a stable high-pressure airflow on the measured surface; the lower end surface of the connecting seat 230 is connected to the adjustable air flotation block 220, which is installed on the fixed guide rail 130 and the fixed groove 140 to adjust the air flotation span; the locking screw 240 is used to lock and fix the connecting seat 230;

The combined connection method of the air-floating bridge plate is as follows: the fixed stopper 110 is connected to the upper end surface of the adjustment mechanism 120 and installed on the front upper surface of the base plate 150, the fixed guide rail 130 is installed in the central area of the rear upper surface of the base plate 150, and the upper center of the connecting seat 230 is installed on the fixed guide rail 130, and the support plates on both sides are installed in the center of the fixing groove 140, and the lower end passes through the base plate 150 and is connected to the upper ends of the two adjustable air-floating blocks 220, and three locking screws 240 are installed on the upper end of the connecting seat 230, and two fixed air-floating blocks 210 are installed at the lower end of the front section of the base plate to complete the combined connection;

Step 3: Calibration of air floating bridge plate

Calibrate that the center lines of the measurement surfaces of the fixed air floating block 210 and the adjustable air floating block 220 are parallel in the X and Y directions, and that the four air floating blocks are coplanar;

Step 4: Assemble the scale positioning device

The ruler positioning device 3 includes a ruler 310, a fixed block 320, and a driving block 330; the lower surface of the ruler 310 is close to the measured surface, the upper surface has standard scale lines in the longitudinal direction for adjusting the position when the span is adjusted, and the central axis is used as a reference line in the transverse direction. The fixed blocks 320 are installed at two ends of the ruler body to fix the ruler, the lower end of the driving block 330 is connected to the ruler, and the upper end buckle groove is connected to the bottom of the air floating bridge plate. When the air floating bridge plate is controlled to move linearly by the driving block, only traction is applied to the air floating bridge plate along the measuring direction, and no force is applied in other directions;

The combined connection method of the ruler positioning device is as follows: the lower surface of the ruler 310 is pressed against the measured surface, the fixing blocks 320 are installed on both sides of the ruler body, the upper end is installed and connected with the lower end of the driving block 330, and the upper end of the driving block 330 is connected with the bottom of the air floating bridge plate to complete the combined connection;

Step 5: Use the air floating bridge to measure the flat surface

First, the surface of the marble slab needs to be cleaned before measurement to confirm whether the bottom of the marble slab is stably supported and free of environmental factors such as vibration sources and local heat sources. Then, according to the requirements of the slab pitch measurement method, the measured surface is divided into sections according to the outer dimensions of the marble slab to form rectangular grid distribution measurement points. The grid distribution measurement points are shown in Figure 3 as 25 measurement sequence points composed of diagonal lines a ₁ ~ a ₂ , long lines a ₃ ~ a ₇ , and short lines a ₈ ~ a _12. Then, the scale positioning device is debugged according to the measurement sequence and length and placed in sequence to overlap on the surface of the measured marble slab. A level is installed above the air floating bridge plate, and the bottom is installed on the sliding block of the scale positioning device. The air floating module is supplied with air to float on the measured marble surface. The air floating bridge plate is driven by the driving block to move to each measurement point of the grid distribution, and the reading value of the level is recorded.

According to the grid distribution measurement point data obtained on the surface of the marble slab, the flatness evaluation criteria are used to convert the base surface according to the minimum condition evaluation result, and the difference between the maximum and minimum values in the slab data obtained by the triangle evaluation criteria is the flatness error of the marble slab surface.

The parts not described in detail in the present invention belong to the well-known technology in the art.

The above descriptions are only some specific implementation methods of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any person familiar with the art within the technical scope disclosed in the present invention should be covered within the protection scope of the present invention.

Claims (6)

1. A device for non-contact measurement of surface shape errors of a flat plate by combining a level with an air-bearing bridge plate, which is characterized by comprising: an air-float bridge plate and a scale positioning device;

The air-floating bridge plate comprises a bridge plate frame, an air-floating module and a connecting seat; the bridge plate rack comprises a fixed stop block, an adjusting mechanism, a fixed guide rail, a fixed groove and a base plate; the air floatation module comprises a fixed air floatation block, an adjustable air floatation block, a connecting seat and a locking screw;

Bridge deck frame: the fixed stop block is used for fixing the level, the adjusting mechanism is used for micro-motion adjustment of the posture of the level, the fixed guide rail is arranged at the center of the base plate and is used as a sliding guide rail of the connecting seat, the two fixed grooves are respectively arranged at two sides of the fixed guide rail and are used for sliding support and locking of the connecting seat, the base plate is used as a reference surface of the air-floating bridge plate and is used for combined installation of parts of the device and providing proper load force;

In the air floatation module: the fixed air floatation block and the adjustable air floatation block are used for outputting stable high-pressure air flow on the surface of the measured flat plate; the lower end surface of the connecting seat is connected with the adjustable air floatation block, and the connecting seat is arranged on the fixed guide rail and the fixed groove and used for adjusting the air floatation span; the locking screw is used for locking and fixing the connecting seat after span adjustment;

The scale positioning device comprises a scale, a fixed block and a driving block; during the use, the ruler body lower surface is closely surveyed the dull and stereotyped surface, and the ruler upper surface vertically is equipped with standard line and is used for the position location when adjusting the span, and the ruler upper surface transversely is equipped with the central axis as the datum line, two the fixed block is installed in the ruler body both ends and is used for fixed scale, and the drive piece lower extreme is connected with the scale, and the upper end passes through mechanical positioning groove and is connected with the air supporting bridge bottom, through drive piece control air supporting bridge straight line removal, when air supporting bridge straight line removal, only exerts traction force to the air supporting bridge along the measuring direction, and other directions are unstressed.

2. A method for non-contact measurement of plate shape errors using the apparatus of claim 1, comprising the steps of:

Step one: selecting an air floatation block as a fixed air floatation block and an adjustable air floatation block;

The shape and the size of the air floatation block are determined according to the shape and the size of the measured flat plate;

Step two: assembling an air-floating bridge plate;

step three: calibrating an air-floating bridge plate;

The inner lateral opposite faces of the fixed air floatation blocks and the adjustable air floatation blocks are parallel through calibration, the outer longitudinal opposite faces of the fixed air floatation blocks and the adjustable air floatation blocks are parallel, and all the air floatation blocks are coplanar;

step four: assembling a scale positioning device;

step five: measuring the surface shape of the flat plate by using an air floating bridge plate;

Firstly segmenting the surface of a detected flat plate according to a pitch method, then adjusting the measuring span of the air-float bridge plate according to a pitch line segment, sequentially driving the air-float bridge plate to carry out non-contact measurement according to diagonal lines, long lines and short lines through a scale positioning device, finally obtaining level meter detection data, and calculating and analyzing flatness errors according to an evaluation rule; the evaluation rule is as follows: and performing basal plane conversion according to the grid distribution measurement point data acquired on the surface of the marble slab, and acquiring the difference between the maximum value and the minimum value in the slab data, namely the flatness error of the surface of the marble slab.

3. The method of claim 2, wherein in the first step, when the measured flat plate is a rectangular flat plate, a rectangular air bearing block is selected, and when the measured flat plate is a circular flat plate, a circular arc air bearing block is selected.

4. The method of claim 2, wherein the step of determining the position of the substrate comprises,

The assembling and connecting mode of the air-floating bridge plate is as follows: the fixed stop block is connected to the upper end face of the adjusting mechanism and is arranged on the front upper surface of the base plate, the fixed guide rail is arranged in the central area of the rear upper surface of the base plate, the center of the upper end of the connecting seat is arranged on the fixed guide rail, the supporting plates on two sides of the connecting seat are respectively arranged at the centers of the two fixed grooves, the lower end of the connecting seat penetrates through the base plate to be connected with the upper end of the adjustable air-floating block, three locking screws are arranged at the upper end of the connecting seat, and the fixed air-floating block is arranged at the front lower end of the base plate to complete combined connection.

5. The method of claim 3, wherein the step of,

The fixed air floatation block and the adjustable air floatation block are respectively provided with two.

6. The method of claim 2, wherein the step of determining the position of the substrate comprises,

The assembly connection mode of the scale positioning device is as follows: the lower surface of the ruler is tightly attached to the surface of the measured flat plate, fixing blocks are arranged on two sides of the ruler body, the upper end of the ruler body is connected with the lower end of the driving block in a mounting mode, and finally the upper end of the driving block is connected with the bottom of the air-bearing bridge plate to complete combined connection.