Inspection of bag making machine

Tension detection
Keeping the material tension constant and accurately controlling the tension fluctuation is an important factor 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 sensors of traditional Bag Making Machine, direct measurement and indirect measurement. The direct measurement of the bearing type tension sensor is composed of the excitation coil and the secondary coil of the piezomagnetic tension sensor. The secondary coil is the inductor. When the magnetic element is subjected to mechanical stress in the measurement direction, the magnetic coupling phenomenon occurs. The induced AC voltage signal which is directly proportional to the mechanical force is generated on the secondary coil, A tension signal proportional to the mechanical force is output; a varistor type tension sensor is installed between the bearing and the frame to record the tension of the drum in the horizontal direction, and the corresponding amplifier is used to process the full bridge voltage supply and measurement signal. The output signal of the amplifier is proportional to the radial force, which can be used for digital display or as the instantaneous value of the closed-loop loop. The advantages of direct tension sensor are wide detection range, fast response and good linearity. The disadvantage is that it can't absorb the peak tension. When the tension control system is disturbed strongly, the system has no time to react, and the tension on the belt changes greatly.
The indirect tension detection method is a kind of position control in essence, and floating roller tension detection is commonly used. When the tension is stable, the tension on the 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. It will feed back the position signal to the tension controller. The controller will calculate and output the control signal.
The direct and indirect tension detection method can simultaneously detect the position signal of the floating roller and the electrical signal of the tension output from the sensor. It has a good buffering effect, and has the characteristics of high precision and high repeatability of closed-loop control.
There is another way to get the tension according to the coil diameter. The speed of the winding shaft is detected by the proximity switch installed at the winding shaft. The current diameter of the winding or unwinding drum can be obtained by cumulative calculation according to the initial value of the winding diameter and the material thickness. According to the change of the winding diameter, the control signal is output to control the winding torque or unwinding braking torque, so as to adjust the tension.
Deviation detection
In the process of material transportation, due to uneven force, uneven thickness, traction roller roundness and other reasons, the horizontal position deviation may occur, so the on-line deviation detection should be carried out in time.
In the early stage, the speed of Bag making machine was not high, and the material deviation was adjusted by the operator according to the actual field observation.
Because the photoelectric sensor has the advantages of simple structure, reliable performance, high precision and fast response, the photoelectric sensor is used to track the boundary of different color areas on the edge of packaging materials, read out the offset between the actual position of the strip and the set position, convert the offset into electrical signal amplification, compare, calculate and analyze, Send the command to the servo controller to control the motor to drive the deviation correction guiding mechanism, and return the strip to the set position, so as to achieve the purpose of automatic tracking and adjustment of conveying.