Function and Usage of Squeegee in Screen Printing(Part 2)

Usually the effective width of the squeegee is between 20MM and 30MM. The selection of the best effective width is based on the flatness of the substrate, the screen image resolution and other printing parameters such as: squeegee angle, speed and ink type.

When printing high-resolution images on flat/smooth substrates, the effective width is small (less than 20MM), high hardness, and fast printing with suitable ink.

On uneven and rough substrates, the effective width should be increased (sometimes 30MM) and the hardness should be reduced. The low-hardness squeegee has poor adaptability and should not be excessively bent. You can also use a three-layer scratch or double-layer scratch Layer scraping. Generally, the effective width increases, the printing speed decreases and the printing angle is increased.

3. Squeegee shape: The squeegee shape refers to the cross section of the squeegee. Most squeegee shapes are simple square squeegees, other squeegees are used for specific printing conditions.

For example, hard squeegee performance is better than soft squeegee, but poor adaptability to the substrate. Using oblique squeegee, the printing edge is easy to deform (similar to soft rubber squeegee). There are three shapes of squeegee for the printer to choose: square scraping (or right-angle side scraping), various oblique scraping and round scraping (horn scraping). The square scraper has a wide range of applications and can provide the maximum printing pressure. The printing angle depends on the effective width.

Oblique squeegee provides maximum adaptability, the printing pressure is reduced, and the printing angle is smaller than the set angle.

Squeegee has the worst adaptability, provides the smallest printing pressure, and the printing angle can be set freely (usually the smallest angle). The above reasons will affect the amount of ink.

4. Knife edge: Knife edge is an important part to complete the four functions of squeegee. The sharpness of the squeegee is a factor in the initial control:

The sharp blade provides the smallest amount of ink and the finest image.

The pure and round knife edge increases the amount of ink and affects the color and line fineness. When printing large areas and simple patterns with transparent oil, the change in color and line fineness is not obvious. When printing fine lines and four-color dots, using translucent (UV) and transparent inks, you will quickly find the deformation of the knife edge. Compare the first and last printed sheets to determine when the squeegee should be polished. .

Since the selection of the squeegee is an important part of printing quality control, the maintenance of the squeegee is also an important link to ensure the normal use of the squeegee. The best way to ensure the quality of the squeegee is to clarify the maintenance of the squeegee before and after printing and how to polish the squeegee through a clear process.

The above information is provided by squeegee supplier.