Problem |
Possible
Cause |
Solution |
Stencil
peels or washes away during washout |
Underexposure |
Perform
a Step Wedge Test |
Poor
fabric preparation |
Degrease
steel and metalized polyester; abrade and degrease synthetics |
Residual
moisture in stencil during exposure |
Under
humid conditions, stencil may require additional drying after backing
sheet removal |
Washout
temperature is excessive |
Stay
below 40°C (104°F) |
Silk
or cotton organdy |
Use
only synthetics, stainless steel, or metalized polyester |
Air
pockets during adhesion |
Fabric
not wet enough |
Mesh
openings must be filled with water; rinse just before adhering; check
fabric preparation; use vertical, newsprint technique for thin CDF®s
and fine mesh |
Poor
fabric preparation |
Degrease
steel and metalized polyester; roughen and degrease synthetics |
Poor
fabric stretching |
Upgrade
stretching method |
Adhering
surface not flat |
Use
completely flat surface |
Irregular
or missing squeegee stroke |
Use
sharp-edged, medium hardness squeegee with slow steady stroke, without
excessive pressure |
Stencil
breakdown |
Underexposure |
Perform
a Step Wedge Test |
Poor
fabric preparation |
Degrease
steel and metalized polyester; roughen and degrease synthetics |
Solvents
too agressive |
Coat
squeegee side with 569FAST; use CDF®/LX or CDF®/QSR
film |
Needs
mechanical reinforcing layer |
Coat
squeegee side with FX88 (RLX for CDF®/LX, QFX for CDF®/QSR
or QTX for CDF®/QT) |
Aqueous
or water-containing ink |
Use
CDF®/LX series or CDF®/QT |
Poor
definition (edge sharpness) |
Waiting
too long before squeegee stroke |
Have
squeegee ready after film contacts wet mesh |
Mesh
too coarse for film |
Use
thicker film; stencil thickness must be related to mesh count |
Underexposure |
Perform
a Step Wedge Test |
Incomplete
washout |
Wash
out thoroughly from both sides |
Poor
Resolution (fine details) |
Positives
lack density |
Remake
positives |
Pre-exposure |
Work
under safelights; store coated screens in dark |
Poor
exposure contact |
Check
vaccuum |
Poor
light source |
Upgrade
light source; increase exposure distance if possible |
Mesh
too coarse |
Use
finer mesh |
Film
too thick |
Use
thinner film |
Overexposure |
Perform
Step Wedge Test |
Pinholes |
Dirt
and dust |
Clean
positives and contact glass; remove backing just before exposure; dust
film emulsion before adhering |
Underexposure |
Perform
a Step Wedge Test |
Solvents
too aggressive |
Coat
on squeegee side with 569FAST; use CDF®/LX or CDF®/QSR
series film |
Poor
fabric preparation |
Check
preparation; adhere as soon as possible after the degreasing rinse |
Difficulty
reclaiming |
Underexposure |
Increase
exposure to fully "cure" emulsion |
Wrong
stencil remover |
Use
only Ulano No. 4, diluted No. 44, No. 42, or No. 5 |
Solvents
too aggressive |
Coat
on squeegee side with 569FAST; use CDF®/LX or CDF®/QSR
series film |
Thicker
stencil needed |
Mesh
too coarse |
Use
finer mesh, if possible; use thicker CDF® Direct-Film;
use Direct/Indirect Method, or Lamination Technique |