The method of controlling tension in the printing process of high-speed electronic axis rotary gravure printing press usually involves multiple links and advanced technical means to ensure that the printing material maintains a stable tension during the transmission process, thereby improving the printing quality and efficiency. Here are some of the main ways to control tension:
First, tension control principle
Tension control refers to the ability to continuously control the tension of the material belt when it is transported on the equipment, and this control must be effective for any running speed of the machine, including the acceleration, deceleration and uniform speed of the machine. In gravure printing, tension control is a key factor to ensure smooth transmission of printing materials, avoid overprinting errors and ensure printing quality.
Second, tension control link
The tension control of high-speed electronic axis rotary gravure press mainly includes the following links:
Feed to feed traction roll:
Tension control point: Tension control from the feed shaft to the feed drag roll is critical. If this part of the tension is not well controlled, it will cause overprinting error, that is, the overprinting accuracy between different colors in multi-color printing is poor.
Control method: Brake is usually used to control the tension, ensuring that the traction roller at a certain speed and tension to pull the material from the feed shaft and into the printing part. With the printing process, the film roll diameter on the feed shaft gradually decreases, so the tension needs to be adjusted accordingly.
Material factors: Different film materials (such as PE, CPP, PET, OPP, etc.) have different expansion rates, so it is necessary to adjust the tension reasonably according to the characteristics of the material.
Tension control during printing:
Synchronous control: The electronic shaft technology drives each color group through a servo motor to achieve precise synchronization of the plate roller and the substrate, thereby maintaining a stable tension.
Real-time adjustment: The advanced control system can monitor the tension changes during the printing process in real time and automatically adjust the operating state of each component to maintain a stable tension.
After receiving the paper pull roller:
Tension control point: From the receiving roll to the various parts of the receiving roll, it is necessary to ensure that the receiving roll is tight, neat and reliable to avoid wrinkles or relaxation of the material during the winding process.
Control method: The use of automatic control system, such as magnetic powder clutch, torque motor or DC motor, according to the material diameter changes gradually adjust the tension to achieve taper tension control.
Third, tension control method
High-speed electronic axis rotary gravure press usually uses the following tension control methods:
Manual tension control:
Although it has been largely eliminated in modern printing presses, it can still be used as an auxiliary means in some cases. The operator controls the tension by adjusting the manual power supply.
Open loop semi-automatic tension control:
Also known as roll size detection tension control. Through the proximity switch installed at the reel to detect the reel speed, combined with the initial reel diameter and material thickness, calculate the current reel diameter and output a control signal to adjust the winding torque or winding torque, so as to control the tension.
Closed loop automatic tension control:
At present, more advanced tension control methods. The actual tension value of the material belt is measured directly by the tension sensor, and compared with the preset tension value, the control signal is calculated and the execution unit is automatically controlled, so that the actual tension value is equal to the preset value. This method has the advantages of high precision, high stability and high reaction speed.
Fourth, tension detection method
In order to achieve accurate tension control, it is also necessary to choose a suitable tension detection method. Common tension detection methods include:
Sensor detection:
Use tension sensors (such as plate spring micro-displacement tension sensor, strain resistor tension sensor, piezomagnetic tension sensor, etc.) to directly detect the tension value of the material belt.
Float roll inspection:
An indirect tension detection method. The change of tension is reflected by the change of float roller position, and the float roller potentiometer is used to feed back the position signal to the tension controller for correction.
Float roller/feedback composite inspection:
In order to improve the accuracy and stability of tension control, two methods of floating roller detection and sensor detection are used simultaneously.
