This paper mainly introduces the application of German HAEHNE tension controller in two tension segments of Titanium and Titanium alloy belt grinding production line. At the same time, according to the different production processes, it introduces the application of tension segments and the simple correction method of tension controller. Titanium and Titanium Alloy Belt Grinding Production Line is the main equipment for strip surface treatment in our unit. It can realize two sets of processes of grinding and degreasing. The tape runs through the sand box of the equipment line to grind the surface of the tape or clean and degrease it.
Sand grinding process: hoisting-unwinding-lead-strap-rectifying head-cutting head-pre-degreasing-pre-cleaning-pre-dewatering-sand grinding-degreasing-cleaning-post dewatering-drying-cooling-inspection-cross shearing-extraction-displacement-rectification-winding-packaging-winding. Degreasing process: sling-unwinding-lead-strap-rectifying-cutting-pre-degreasing-pre-cleaning-pre-degreasing-degreasing-cleaning-post-degreasing-drying-cooling-inspection-lead-back-driving-shearing-rectifying-winding-packaging-unwinding. Starting process operation is smooth, without external tools or additional welding machine, double-sided grinding can be completed at one time. Cleaning equipment before grinding can clean the oil stains on the surface of hot-rolled titanium strip in advance to ensure the quality of grinding. The grinder adopts servo motor actively, which has stable output of rotation distance, long-term use and energy-saving benefits. The control system adopts IPC with PLC and man-machine interface, which is easy to operate. The automation structure is a two-level system with three-level interfaces reserved.
The importance of tension is well known, especially in the process of strip production and processing, which is an indispensable important factor, such as rolling process, stretch bending straightening process, etc. At the same time, tension is also of great significance in the process of defatted sand grinding. Tension is produced by the speed difference between the coiling mechanism (such as coiler, winder, puller, etc.) and the uncoiling mechanism and the pressure rolling or intensifying equipment on the equipment produced by a single machine. It can be seen that due to the speed difference between various kinds of equipment, there is a certain tension in the strip, which is called tension in daily life. There are two tension sections in the production line of defatted sand grinding: the first tension section, called the middle tension section, removes water from the back to the back drive. The second tension section, known as the back tension section, drives from the pull-out back to the winder. The tension input in the middle section prevents the occurrence of stacking in the grinding process, ensures the stability of the strip in the grinding process, thermostatic element and ensures the surface smoothness and good shape of the strip.
The input of back tension prevents coiling into tower shape during coiling process, so that the strip can enter coiling accurately and coil evenly to ensure the straightness of the strip.
Tension sensor uses strain principle as measuring unit and uses high stability DC source (voltage source or current source) to excite, which can obtain fast response to force change (or load change). The tension measuring system can be used not only in modern high-speed tandem cold rolling strip mill, but also in accurate measurement and control of strip tension in non-ferrous metal strip mill, paper mill, textile machine and other industries. When the tension of strip is measured in steel industry, the tension sensor can be used not only for vertical tension measurement, but also for horizontal tension measurement. Tension measurement principle: strip (strip or paper) is tensioned on the tension roll, and the tension roll is installed on the tension sensor. According to the working form of the tension sensor, the tension of the strip can be measured either by measuring the horizontal component or by measuring the vertical component. Among them: T – stands for tension, and the weight of tension roll and bearing seat is compensated by electric method. If a vertical tension sensor is used, the tension is measured by measuring the vertical component FV of the tension; if a horizontal tension sensor is used, the tension is measured by measuring the horizontal component FH of the tension. If the angle between the strip and the tension roll is constant (known), the output signal of the sensor is proportional to the tension. The tension can be measured. Tension sensors installed in grinding production line are used to measure tension by horizontal method. The working principle of HAEHNE’s tension legend is the resistance strain principle: when the elastic problem of the sensor is acted by force (F) in the direction of measurement, the elastomer deforms (L), and the resistance strain gauge pasted on the elastomer also deforms, and the resistance value of the resistance strain gauge changes (R). The resistance change of the strain gauge is transformed by using the Whiston bridge. Voltage or current changes (V or L) are measured after signal amplification.
Whiston Bridge can measure small disturbances accurately without temperature compensation. The output voltage is proportional to the applied pressure. The production line adopts Mitsubishi PLC and Anchuan frequency converter for electrical control of the whole line. At the same time, three remote operation desks are used in the front, middle and back sections. Traction part: Traction generally adopts speed control power mechanism, its main task is to pull the product forward. Tension detection part: It is between traction and unwinding or winding. When the product is passed through the tension detection part, it can detect the dynamic instantaneous tension. It is a direct detection of tension, closely combined with machinery, is not a mobile parts detection method. Usually two tension sensors are used in pairs, and they are mounted on the end axles on both sides of the inspection guide roll.
The raw material exerts pressure by detecting the guide roll, which causes displacement or deformation of the tension sensor’s sensitive element, and then detects the actual tension value. Tension detection part: It is between traction and unwinding or winding. When the product is passed through the tension detection part, it can detect the dynamic instantaneous tension. It is a direct detection of tension, closely combined with machinery, is not a mobile parts detection method. Usually two tension sensors are used in pairs, and they are mounted on the end axles on both sides of the inspection guide roll.
The raw material exerts pressure by detecting the guide roll, which causes displacement or deformation of the tension sensor’s sensitive element, and then detects the actual tension value. Tension control methods are generally divided into open-loop control mode and closed-loop control mode. Open-loop control is to drive the winding mechanism directly with a motor with similar winding characteristics n=kD (n is the speed, K is the constant, D is the diameter of the roll). The winding mechanism is operated under the approximate constant tension by direct operation of PLC. It has no tension detection link, and the open-loop control has poor randomness and low control precision. Closed-loop tension control has tension detection link control. In actual production process, the tension is feedback to the PLC. Compared with the given tension, the difference is calculated and adjusted by the PLC to adjust the controlled object so that the output tension meets the actual demand. This control method is called direct tension closed-loop control.
The method can eliminate steady-state error without considering all kinds of compensation and has high control precision. The simplest manual control mode is adopted in the back tension section. The producer calculates the tension required for winding according to the thickness and width of the strip. Then the tension value is input manually through the knob in the back winding torque tension control module.
Then the tension value is transmitted to the required tension value by Mitsubishi CC-LINK digital transmission module in the back section. The data transmission module in the middle stage is equipped with the remote data transmission module of Mitsubishi PLC, which is responsible for communicating with the PLC of the electric control cabinet force. After the data is inputted into the PLC, the output of the winding motor and the frequency converter of the rear drive motor is controlled by the PLC, and the speed of the two sets is adjusted to achieve the required tension.
Back tension is a stage control in the whole line.
Manual control mode and CPC edge alignment device can solve the problems of roll collapse and tower shape. The middle tension is put into use only when the grinding process is carried out in the production line. The tension controller adopts a different pin connection method from the back tension controller to realize the full automatic control mode. In our usual work, we will do simple calibration work for the tensiometer. The method is as follows: using a soft cloth belt, one end is tied to the mandrel of the winder, the other end simulates the form of strip production, passing between the two rollers driven by the rear, and then hanging on the crane hook scale, at the same time, the tension sensor rises to the limit position.
Firstly, the zero position of the tensiometer should be corrected, and the crane hook should be lifted so that the soft cloth bandage is tightly attached to the sensor. The hook scale shows 0 kg.
At this time, we adjust the knob on the tensiometer amplifier to make the tensiometer display 0 accurately. Then the crane is lifted to correct 500kg, 1000kg, 2000kg and 3000kg at a time. We will also adjust the knobs on the amplifier to ensure that the values displayed by the tensiometer are consistent with those of the hook scale, thus achieving a simple correction of the tensiometer.