Squeegees can influence printing results, but only if other variables in the process are controlled. This means understanding the properties of your inks, as well as using high screen tension, low off contact distance and press settings that don’t over saturate the screen with ink. After optimizing these variables for a particular job it’s time to select the squeegee based on the following parameters: durometer, blade profile and blade edge profile.
Durometer: This refers to the hardness of the squeegee. It affects the squeegee’s adaptability to the surface and determines the amount of printing force transmitted to the screen and the substrate. Soft squeegees are more adaptable and transmit less force than hard ones.
Profile is the shape of the squeegee’s printing edge. This shape also determines the squeegee’s adaptability. In a sense, profile fine tunes this adaptability and limits the amount of force transmitted to the printing surface.
The profile affects the relationship between the set squeegee angle and the effective squeegee angle relative to the screen in the direction of the print stroke. The effective angle is the actual angle during printing, when the force of the print stroke deflects the squeegee beyond the set angle. The smaller the effective squeegee angle, more ink is forced into the screen ahead of the printing blade and less ink is scraped off the screen surface.
Depending on the profile you select, the squeegee will force more or less ink into the screen, thereby influencing the printed ink deposit thickness. Profile options include the following:
Square/rectangular: This profile provides medium adaptability and maximum force. When using a square/rectangular profile, the effective angle approximates the set angle. This is the most frequently used profile in screen printing.
Beveled Edges: These can be beveled in various ways to provide maximum adaptability and minimum force. With beveled profiles, the effective angle is always less than the set angle. Beveling is most effective when used in applications requiring squeegees less than 14 inches long.
Round Squeegees: a round profile provides minimum adaptability and minimum force. With such squeegees, the effective angle is always very small and nearly independent of the set angle.