Ultra-high precision automatic caliper detection principle
Key words: automatic caliper; bar; round steel;
introduction
In the steel industry production, there are many traditional round steel caliper methods, such as sampling tools using dimensional tools and electromagnetic contact measurements. Measuring with a dimension tool, the accuracy is not enough and the speed is very slow; the electromagnetic measurement is a contact measurement, the measurement is troublesome and the accuracy and speed are difficult to guarantee. CCD charge-coupled devices are widely used in photodetection and photo-imaging in image scanning, non-contact size detection, displacement measurement bar code reading, etc. It has the advantages of self-scanning, high precision, high sensitivity and wide spectral response. CCD non-contact round steel photoelectric automatic caliper is a non-contact round steel special automatic caliper based on CCD photoelectric detection technology. It has the advantages of non-contact, high speed, high precision, automatic measurement, etc. Under the harsh conditions of darkness, high temperature and high speed, the real-time monitoring of the small changes of the round wire diameter in the production line on the production line has high practical value.
1, the principle of measurement
The launch lens has a point source built in, and the light from the point source passes through the lens system (ie, the lens group) to form a collimated parallel field of view. The collimated parallel light is directly directed to the receiving lens, is focused by the lens system in the receiving lens, and is imaged on the CCD chip through the aperture of the aperture located at the focus position. When the object passes through the object in the field of view, the area blocked by the object under test will have a clear shadow on the CCD. The CCD chip is a photoelectric conversion element in the probe component that converts the received optical signal into an electrical signal. The electrical signal is received and amplified by the signal acquisition circuit, and then digitized and transmitted to the upper computer.
The line sync pulse FC of the CCD and the standard pulse SP and the output signal U. The relationship is shown in Fig. 2(a), after the workpiece is placed, U in the middle of the line sync pulse FC. The waveform part period becomes a low level, and the width of the low level varies linearly with the workpiece diameter size, as shown in (2b). U is in each line pulse FC cycle. Signal processing is performed to prepare for subsequent pulse counting.
2, the probe constitutes
Because the cross section is not a perfect circle in the production of round steel, the roundness is also an important test item. In order to achieve higher performance detection, the automatic caliper achieves the full diameter of the round steel with eight sets of photoelectric probes. Detection. The automatic caliper measures the size of the wire diameter in eight directions of the same section, and because of the twisting of the round steel in production, the caliper can comprehensively detect the cross-section information of the round steel and obtain the ellipticity information. And the sectional view information can basically reflect the true cross-sectional dimension of the rolled material. The cross-sectional view can clearly see the production state of the same section of the round steel. The distribution of the probe and the measured cross-sectional dimension are as shown in the following figure.
3. Software system
The caliper is equipped with a professionally developed software system. The measuring system is divided into two types: "round steel measuring system" and "reel steel measuring system" depending on the type of wire. This paper mainly introduces the round steel measurement system.
Online display mode
(1) The section description of the bar is determined by the current measurement of the eight axes. The same form displays the current measurement in digital form. When it is out of tolerance, the corresponding form number will turn red.
(2) The maximum diameter, the minimum diameter, the average diameter, and the ellipticity of the same section are displayed, and the same number turns out to be red.
(3) Sectional view: shows the state of the same section, between the two red lines is normal, if it is exceeded, it is unqualified, and the section view can clearly see the section state of the bar.
(4) Trend chart: In the time axis, you can view the status of the entire bar at different times and grasp the whole bar.
(5) Fluctuation map: The fluctuation state of bar production in eight measurement directions is displayed in units of time axis, and the corresponding diameter condition at any time can be observed.
(6) Defect map: The type of over-measurement of the eight-way measured value can be observed. The rolling defect distribution of the bar can be obtained in a very vivid and timely manner at the rolling site, especially the head-tail defect characteristics of the rolled material, and its continuation. The length, so that the rolling process configuration is moderately adjusted.
(7) Full-screen display of stored data: Historical data can be stored for a long period of time, and the historical data can be exported in Excel form.
(8) The main interface can display the measured bar type, nominal diameter value, allowable positive tolerance, allowable negative tolerance, thermal expansion coefficient, board temperature and other information.
Conclusion
Automated calipers offer the possibility for rolling mills to increase product yield, quality and automation. The automatic caliper uses multiple axes for measurement, making it possible to detect the same section size without rotating parts, increasing the service life and reducing damaged parts. The use of automated calipers brings convenience to the rolling mill. Improve the automation level of the manufacturer and accurately monitor the quality of the products.
After reading this article, do you have any thoughts or suggestions on the measurement of bars, round bars, etc., even if you leave a message or a private letter in the article below, some message posts are not displayed here, and you can't reply in time. Xiaobian will do everything possible to share information and experience with everyone. An automatic measuring device that measures width, length, thickness, and outer diameter can be used to leave a message below.
China Stainless Steel Medical Device Processing,Stainless Steel Medical Device Processing Service
ShenZhen Haofa Metal Precision Parts Technology Co., Ltd. , http://www.haofametals.com