Many of us think screen printing is an ART but I strongly believe one should treat Screen Printing as a science or Engineering Process:

When we accept it as a science. Now start defining problems to get solutions.

Define fundamentals and refine your process to control final output i.e. predictable prints.
 
Screen Printing inks

Various ink-related variables such as viscosity and pigment particle size.
Overlooked variable: evaporation speed of solvents and water in ink, Appropriate mesh selection.

No considerations of evaporation for conventional UV-curable ink.

Recommendation: For solvent ink keep ready mix with solvent then add small amounts of ink frequently. Select mesh keeping in mind the pigment particle size.
 
Significance of the Squeegee

Various squeegee related variables like durometer i.e. rubber hardness, angle, pressure, speed of squeegee

Importance of squeegee mechanism is to ink transfer to substrate.
Overlooked variables: sharpness of squeegee edge, squeegee rest time.

Recommendation: keep squeegee rubber rested for 8 hours after its use for 2-3 hours every time. Sharpen your squeegee only after its rest hours.
 
Floodbar Functionality

Purpose: Cover or flood mesh openings with ink before squeegee action.
Overlooked variable: Floodbar determines ink prefill amount on stencil which determines ink deposition on print substrate and drying time of deposited ink.

Recommendation: Proper use of floodbar like edge type- sharper or rounded, optimized contact with stencil and enough quantity of ink on screen.
 
Press Setup and Operation

Overlooked variable: Improper or inconsistent press set up like substrate to stencil gap and parallel ness, squeegee angle, pressure, and speed.

Recommendation: Importance of recordkeeping. Ensure consistent setup across multiple colors or machines, Material preparation for minimal downtime and keep continuous operation for consistent print quality.