Page 23 - SCREEN PRINTING FOR BEGINNERS

Surface smoothness can affect Capillary films suffer from a past

your substrate to stencil gasket. bad reputation for delamination
The lower Rz numbers will be (Fig. 6) the current products
produced only by machine coating available are capable of long runs
or film products. Direct/indirect and excellent detail. Capillary films
and capillary films will produce the produce the lowest Rz numbers
lowest Rz numbers possible for possible and can save large

screen stencils. High solids content amounts of screen room
emulsions and face coating production time.
(second or more coats of emulsion
over dry first coatings) can also
lower your RZ measurements. (Fig.
4) Exact EOM and Rz numbers can
only be measured by special

testing equipment.
Fig. 22 Measuring dry emulsion
Indirect film products are

presensitized emulsions on film.
They are produced to expose and
develop before they are attached
to the screen mesh. Indirect film

has fallen out of general use as
products that are easier to use and
have superior reproduction
properties are now available.
Capillary films are photosensitive
emulsions layered onto a film
backing. (Fig. 5) The name is

indicative of the action that causes
the adhesion, capillary action. With
Fig. 23 Capillary films
wet screen fabric, the film will

draw into the mesh when placed
in contact with the face of the
screen.

Fig. 21 Measuring dry emulsion Fig. 24 Delamination of capillary films

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