Keeping the material tension constant and accurately controlling the tension fluctuation are important factors to improve the production efficiency and control the quality of bag-making. Tension detection is the basic premise of tension control.
There are two kinds of tension sensor of traditional bag making machine: direct measurement and indirect measurement. Direct measurement of tension sensor has a socket type, such as excitation coil and secondary coil of the magnetic needle of the tension sensor of secondary coil for sensor, when magnetic components in measuring direction by magnetic coupling phenomenon, which appear when mechanical stress on the secondary coil and mechanical force is proportional to the induced voltage signal, through signal processing, Output a tension signal proportional to the size of the mechanical force; The varistor type tension sensor is mounted between the bearing and the frame to record the horizontal tension of the drum, and the corresponding amplifier is used to supply the full bridge voltage and process the measured signal. The output signal of the amplifier is proportional to the radial force and can be used for digital display or as the instantaneous value of the closed loop. There is also a plate spring type micro-displacement tension sensor. Direct tension sensor has the advantages of wide detection range, fast response speed and good linearity. The disadvantage is that it can not absorb the peak tension. When the tension control system is disturbed strongly, the system can not make a response in an instant, and the range of the tension of the material belt is large.
Indirect tension detection is essentially a position control, and floating roller tension detection is commonly used. When the tension is stable, the tension of the material belt is balanced with the force of the cylinder, so that the floating roller is in the central position. When the tension changes, the position of the floating roller will rise or fall. The floating roller potentiometer will detect the change of the position of the floating roller, and it will feed back the position signal to the tension controller. The controller will calculate and output the control signal.
Combining the direct and indirect tension detection methods, the floating roller position signal and the tension electrical signal output by the sensor can be detected simultaneously, which has a good buffering and stabilizing effect, and also has the characteristics of high precision and high repeatability of closed-loop control.
Another according to the diameter of tension testing ways, to install in the scroll of proximity switch to detect the scroll speed, and through the setting of scroll diameter initial value and the thickness of the material, the cumulative calculation for winding or the diameter of the drum of the current, the output control signal according to the variation of roll diameter, rolled to control winding torque or regulated torque, so as to adjust the tension.