TROUBLESHOOTING TYPICAL SCREEN PRINTING PROBLEMS

The following are suggestions for common screen printing problems that can occur with most models. These are geared toward using UV cure inks. For more suggestions, or application questions, it is best to call you ink supplier or manufacturer.


Bubbling

Small air bubbles on printed solids. Ink too thick (viscous) Thin out ink.


Ink contains bubbles from high speed mixing. Allow bubbles time to disperse or reduce mixer speed.


Printing speed too fast. Reduce squeegee speed.


Too much ink deposited. Use harder squeegee to transfer less ink.

Contamination

Non-inked spots in image area. Lint/dust in image area of screen. Clean Screen, Increase humidity level. Clean work area regularly.


Contaminated substrate. Avoid handling substrate in area to be printed. Take steps to remove dust just prior to printing.

Leaks, Bleeds & Pinholes

Ink spots in non-image area. Holes in non-image area of screen. Spot out with blockout or tape or remake stencil.


Ink leaks around image. Foreign material under stencil near image edge. Clean underside of screen.


Ink too thin. Stiffen ink or remix.

Ink Spreading

Thickening of image, unsharp edges, ink spreading around image edges. Ink too thin. Stiffen or remix ink


Excessive flood coat pressure pushes ink through screen. Flood bar should not be touching the screen during the flood cycle.


Squeegee profile too rounded. Sharpen squeegee.


Too little snap-off. Increase off-contact distance or retention/remake screen.


Too much snap-off. Reduce off-contact distance.


Static; press sheet does not completely drop off screen. Add anti-static agent to ink.
Ground the table bed.Incorporate static eliminators.Mask out non-image area with paper on the underside of screen.

Blur/Ghosting

Double edges at edges. Insufficient snap-off. Increase off-contact distance


Image blurred and/or distorted. Press sheet sticks to mesh due to static. Reduce speed. Increase vacuum. Increase snap-off.
Add anti-static agent to ink.Ground the table bed.Incorporate static eliminators.Mask out non-image area with paper on the underside of screen.


Ink contains bubbles from high speed mixing. Allow bubbles time to disperse or reduce mixer speed.


Printing speed too fast. Reduce squeegee speed.


Too much ink deposited. Use harder squeegee to transfer less ink.