The control of printing pressure in automatic screen printing machines is one of the key factors to ensure printing quality.
1、 Mechanical structure adjustment
Automatic screen printing machines usually have specialized pressure regulating devices. There is a pressure adjustment knob or cylinder adjustment device between the screen frame of the machine and the printing platform. By rotating the knob, the distance between the screen and the substrate can be changed, thereby adjusting the pressure. For example, when the knob rotates clockwise, the screen gradually approaches the printing platform and the pressure increases; Rotate counterclockwise to reduce pressure. For automatic screen printing machines that use cylinder controlled pressure, the pressure level can be changed by adjusting the intake volume of the cylinder. Generally, the air pressure parameter can be set on the control panel of the device. The higher the air pressure, the greater the force of the screen pressing down, and the higher the printing pressure.
2、 Adjust according to the characteristics of the substrate
Different substrates have different requirements for printing pressure. For example, when printing paper, due to the relatively soft texture of the paper, excessive pressure may cause deformation of the paper and uneven ink penetration. In this case, the printing pressure is usually set to be relatively low. If it is a hard material such as a printed plastic board, it is necessary to increase the pressure appropriately to ensure that the ink can be fully transferred to the surface of the substrate. When printing materials with certain elasticity, such as rubber products, pressure control is more complex. It is necessary to ensure ink transfer while avoiding excessive deformation of the material that affects the quality of the pattern.
3、 Adjust with sensor feedback
Advanced automatic screen printing machines are equipped with pressure sensors. During the printing process, sensors can monitor the pressure between the screen and the substrate in real time. When the pressure deviates from the set value, the control system will automatically adjust the pressure regulating device based on the feedback information from the sensor. For example, during high-speed printing, pressure changes may occur due to machine vibration or slight deformation of the screen. At this time, the pressure sensor will come into play to correct the pressure in a timely manner, ensuring the stability and consistency of the printing.
4、 Testing and Calibration
In practical operation, pressure testing is required to determine the optimal printing pressure. You can observe the clarity of the printed pattern and the adhesion of ink through trial printing. If there are blurry patterns, thick or thin ink, etc., it is necessary to adjust the pressure. And it is also important to regularly calibrate the pressure regulating device to ensure the accuracy of pressure control, which usually requires the use of professional measuring tools.