Working principle of flat screen printing machine

The working cycle program of flat screen printing machine. Taking the flat screen platform type monochrome semi-automatic hand screen printing machine as an example

The working cycle program of flat screen printing machine. Taking the flat screen platform type monochrome semi-automatic hand screen printing machine as an example, its working cycle is: feeding → positioning → plate dropping → lowering to the ink plate, lifting back to the ink plate → scraping stroke → raising to the ink plate → lowering back to the ink plate → lifting the plate → ink return stroke → releasing positioning → receiving the workpiece.

In continuous loop actions, as long as the function can be achieved, the time occupied by each action should be as short as possible to shorten the synchronization of each work cycle and improve work efficiency.

Impression line. In the printing process, the ink and screen printing plate are pressed onto the ink plate, forming a contact line between the screen printing plate and the substrate, which is called the embossing line. This line is located at the edge of the ink scraper, and countless embossing lines form the printing surface. It is difficult to achieve an ideal embossing line because the printing process is a dynamic process.

Working principle of screen printing machine. Taking the commonly used hand shaped flat screen printing machine as an example, the working principle of the screen printing machine can be described as follows: the power is transmitted through the transmission mechanism, causing the ink scraper plate to press the ink and screen printing plate in motion, forming an imprint line between the screen printing plate and the substrate. Due to the tension N1 and N2 of the screen, a force F2 is generated on the ink scraper plate, and the rebound force prevents the screen printing plate from contacting the substrate except for the imprint line. Under the pressure F1 of the ink scraper plate, the ink leaks from the moving imprint line to the substrate through the mesh holes.

During the printing process, the screen printing plate and the ink scraper move relative to each other, and the squeezing force F1 and the rebound force F2 also move synchronously. Under the action of the rebound force, the screen returns to its original position in a timely manner and is out of contact with the substrate to prevent the imprint from getting dirty. The screen is constantly undergoing deformation and rebound during the printing process.

After completing one-way printing, the ink scraper separates from the substrate together with the screen printing plate and performs a return ink cycle, completing one printing cycle. The distance between the top of the printed material and the back of the screen printing plate after ink return is called the same plate distance or screen distance, which should generally be 2-5mm. During manual printing, the operator's technique and proficiency directly affect the formation of the embossing line. In practice, silk screen workers have accumulated a lot of valuable experience, which can be summarized into six points: ensuring the straightness, uniformity, equiangular shape, pressure equalization, centering, and verticality of the ink scraper during movement. That is to say, during printing, the ink scraper should move in a straight line and cannot shake left or right; Cannot be slow in the front and fast in the back, fast in the front and slow in the back, or sometimes slow and sometimes fast; The inclination angle of the ink plate should remain constant, and special attention should be paid to overcoming the common problem of gradually increasing inclination angle; The printing pressure should be kept uniform and consistent; Keep the distance between the ink scraper and the inner sides of the frame equal; Keep the ink board perpendicular to the frame.