AI solutions for the steel industry

Steel bar multi-lengths flying shear precise measurement and control system

Optimizing the length of the tail steel of high-speed bars can effectively avoid steel stacking accidents, reduce the length of steel, and improve the yield rate.


The precise measurement and control system of steel bar multi-length flying shear can accurately measure the length of rebar, and the measured data is used as a verification and detection method to participate in the control system.

DBM is responsible for the design, modification, installation, commissioning, construction guidance, system integration and other implementation work of this project, and is responsible for the world’s advanced nature, reliability and integrity of the system.

(1) Project content

The ZKWS-LG-100 multi-scale length measuring system is planned to be installed behind the 18# rolling mill in the first working area of the bar. The system uses a visual recognition system, dynamic measurement, and online non-contact measurement to accurately measure the steel length online and The measured data is fed back to Party A’s computer system for production control.

(2) Drawing description

All drawings in this document are schematics for illustrative purposes only. Formal drawings are provided during basic design and detailed design.

Equipment technical specifications

1) Equipment composition

The basic configuration is as follows:
✓ Length measurement and identification system software based on machine vision
✓ UHF high-precision length measurement module
✓ Control module and touchscreen
✓ Identify host
✓ Hot metal detector
✓ Electrical control system and cabinet
✓ Other auxiliary materials

laser surface velocimeter, Cable industry

2) Measurement principle

According to the user’s technical requirements for this project and the actual site conditions, without changing the original equipment and plate rolling process, this solution uses an advanced vision system and uses an ultra-high frequency and high-precision length measurement module to identify the dynamic speed of the material, thereby Realize online dynamic length measurement function.

The working diagram is as follows:

bar length measurement, bar production

1-Finishing mill, 2-Dynamic online precision length measurement, 3-Water penetration device, 4-Pinch roller, 5-Segment flying shear, 6-Tail collection box

3) Technical implementation plan

(1) Function description

It is used to measure the length of the rebar in real time. The operator can observe the length parameters of the rebar during operation through the display, and the measurement results can be transmitted to the user’s computer system. The main functions are described as follows:

✓ Measure the length of rebar (round bar) online and non-contact;
✓ Internationally leading anti-shake and high-speed measurement technology, specially developed for high-speed rolling mills, can effectively eliminate the impact of rolling material jitter and solve the problem of slippage and inaccurate measurement of the original rolling line encoder.
✓ Automatic calculation function of the offset of the material from the centre line;
✓ In-position signal: Fixed-point shooting based on the in-position signal;
✓ With length correction function;
✓ Data and quantity: automatically measure and automatically identify the current length;
✓ Length inspection and alarm function;
✓ The HMI screen has functions such as display of measurement data, equipment body system working status, equipment fault codes, fault information and fault self-diagnosis.
✓ Historical measurement data can be retained for more than one year, and server backup data can be uploaded.
✓ Due to its “non-contact” measurement characteristics, this system has no wear and tear. It can not only minimize the maintenance cost of the production line, but also significantly improve the reliability of the assembly line, improve production efficiency and product quality, and ensure accurate product specifications. Significantly reducing production costs can improve an enterprise’s competitive advantage.

(2) Dynamic measurement implementation plan

Dynamic length measurement adopts the principle of ultra-high frequency spectrum monitoring signal scanning. It locates the material through one (or more) ultra-high frequency high-precision length measurement module installed at the roll gap, automatically determines the material frame rate, and sends the information to a dedicated high-speed The digital signal processor system performs analysis and processing to obtain accurate length information of the rebar (bar).

speed and length measurement


The speed measurement of the ultra-high frequency and high-precision speed and length measurement system uses the differential Doppler principle. The speed meter adopts spatial filtering technology, uses LED (light-emitting diode) light sources and linear array CCD chips to achieve linear velocity measurement of space luminous particles. In practical applications, high-brightness LEDs are used to illuminate the surface of the object to be measured. The uneven arrangement of particles on the surface of the object to be measured will produce reflected light of different sizes and angles, forming luminescent particles. After passing through the optical lens, the luminescent particles will The imaging is generated on the special detection device—line array CCD, and a frequency signal proportional to the speed of the luminous particles is output at the output end of the special signal processing circuit. The fast Fourier transform solution can be obtained by computing and processing the frequency signal. The moving speed of the object being measured is the linear velocity. The integral of the linear velocity over time is the length.

Used to measure the length of the bar in real time. The operator can observe the length parameters of the bar during operation through the display, and the measurement results can be transmitted to the user’s computer system. The main functions are described as follows:

✓ The ultra-high frequency and high-precision speed and length measurement system is installed on the integrated circuit chip CCD inside the instrument. The CCD chip has stable performance, long working life, and is basically not affected by the working environment and temperature.

✓ The measurement accuracy of the tachometer is guaranteed, and the performance is stable and reliable; the frequency signal generated by the tachometer on the CCD is clear and stable, and after wave collection and filtering, the output refresh time is very short;

✓ The speedometer can be used in more situations and can make effective measurements on almost any surface: the function of the light source is only to illuminate the surface of the object being measured and produce luminescent particles. The cleanliness of the surface of the object being measured affects the quality of the received signal. It is very small and can measure very bright, oily, rough, and hot surfaces, including metals, nonmetals, and even pulp with a concentration of 0.2%;

✓ Strong anti-fluctuation ability, larger jump range adaptability than ordinary laser speedometer;

✓ Power supply information: rated voltage 24v AC power supply, rated current 2A;

✓ Length curve, including deviation curve;

✓ Temperature compensation of hot and cold billets during the calculation process;

✓ Measurement method: vertical to the surface of the object being measured;

✓ Digital automatic following bandpass filtering technology enables the sensor to obtain better signals, making measurements more accurate and response time shorter. The brightness of the LED light source of the speedometer itself can also be adjusted. According to the reflection of the surface of the object being measured, the brightness of the light source can be adjusted to obtain the best measurement signal. Therefore, the speedometer can be better used in situations with large water mist, such as 5-stand cold rolling mills, and can better adapt to changes in oil stains, brightness and roughness on the surface of the measured object. The white light source is a full-spectrum light source that has a stronger ability to penetrate water vapor mist and is more suitable for cold rolling mills with heavy water mist;


Equipment parameters

✓ Minimum measurement speed (m/min): 0

✓ Maximum measuring speed (m/min): 20000

✓ Unit of measurement: m/s, m/min, ft/s

✓ Accuracy: better than 0.05%

✓ Repeatability error: better than 0.02%

✓ Direction detection: Automatic direction detection

✓ Signal output AB pulse, RS422, RS485

✓ Power supply voltage: 20 ~ 28 VDC

✓ Power consumption: 11W

✓ Protection level: IP66

✓ Temperature range: The internal temperature of the instrument is 0-50℃ (a protective box can be added to adapt to harsher environments)

✓ Anti-electromagnetic interference level: Standard Level 4

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