introduction
With the continuous improvement of rod and wire rolling technology, the rolling speed is also faster and faster. The maximum rolling speed of the bar is 18~36m/s, and the wire rolling speed is 60~120m/s. The high-speed traveling object is in motion. The jitter (axial motion) and the twisting (radial motion) place high demands on the measuring equipment: The measurement (contour sampling) time must be short enough, otherwise the motion of the measured object is too large during the measurement, which will result in Excessive measurement error. Continuous improvement of the rolling process requires more information on the 'biting' of the rolled material - entering the rolling mill (head) and 'exiting' - leaving the rolling mill (tail). I hope to get the same At the moment, the measurement data of each axial direction of the same section is convenient for the analysis of the rolling process.
principle
The basis for measuring the contour size is to measure the projection size in all directions. The projection size measurement for a certain direction is referred to as the outer diameter or width measurement. The non-contact outer diameter measurement technology at home and abroad mainly has two types of laser scanning method and photoelectric imaging method. Today The main thing is the photoelectric camera method.
Photoelectric imaging
A continuous (not scanned) parallel beam is formed by the optical system to form an occlusion shadow electronic image on the receiving lens array CCD, and the projection size of the object corresponding to the shadow region of the parallel beam is obtained by image processing.
The advantage of this measurement method is that there are no mechanical moving parts, and there is no error caused by wear. It uses an electronic camera to capture the shadow of the beam at the same time. The general imaging speed is much larger than the speed of the laser scanning, so the error of lateral jitter is much smaller than that of the laser. Scanning method.
The bar caliper can measure up to 500 Hz or even higher. With a dedicated high-speed electronic shutter, this is necessary to accurately measure the outer contour of high-speed moving objects.
Compared with the laser scanning method, the photoelectric imaging method has high dynamic measurement accuracy and long service life. Its main disadvantage is that the volume and weight are larger than the laser scanning caliper, and the signal processing is complicated. instrument The basic principle is to measure the projection width of an object, so not only the outer diameter of the object but also the width can be measured. Different diameters or widths can be measured by different combinations of photoelectric measuring heads.
The bar caliper adopts multiple probe fixed measurement methods to arrange N parallel optical calipers on the same cross section, and the measurement trajectory forms an external 2×N shape. As the N increases, the measurement trajectory approaches the complete Circular section projection, when N≥8, the basic circular section measurement is basically realized.
The biggest advantage of this method is that the same section measurement can be completed at the same time. When N≥8, the measurement of the cross-sectional profile size of the wire bar can be fully completed. When N≥8, the system reliability of this measurement method, Stability is optimal.
Photoelectric imaging, such as light source, lens, detection component (photocell, CCD), etc., require the relative position of the machine to be stable, otherwise it is difficult to ensure the measurement accuracy. The 8-axis caliper uses our proprietary technology, and its light source life is longer than that of the halogen lamp. It is more than 10 times longer. The photoelectric system of 8 axis diameter measurement has reinforcement design. For the high temperature, dust and water gas effects of steel, water cooling, purging, isolation and other protective design are overcome.
This article Baoding Lanpeng Measurement & Control Technology Co., Ltd. write
