Photolithography is a lithographic
reproduction process to generate a
pattern through light exposure on a matrix
board coated with photoemulsion.
This process enables extremely fine 2-D
parts to be manufactured.
For the manufacture or reproduction of
highly-precise and complex parts, nickel
or copper is primarily used. The parts
are often finished with a plating of gold
or silver.
The hole geometry can be made
square, hexagonal, slot-form or round
in different patterns or even as computer
point. Wall thicknesses of 0.01 mm
to 0.5 mm and larger are possible. The
shape of the bridges can also be made
conical on one or both sides.
The process allows both flat and cylindrical
patterns to be executed; the latter
method also allows the production of
seamless cylinders.
Conventionally, the design to be produced
is firstly copied on to litho-film.
The film is then laid onto the mandrel,
which has been evenly coated with a
light-sensitive photo-resist and then
exposed to UV-light. After exposure,
the photo-resist is then developed with
water or an appropriate solvent, whereby
the non-exposed parts of the resist
are easily washed out. The exposed areas
are hardened by the UV light and
remain on the mandrel, which can now
be placed in the nickel bath for plating.
Once the nickel plating has been done,
the plated parts can easily be removed
from the mandrel.
Areas of application: drum filters,
sieves and screenprinting, razor foils,
food & tobacco industry screenprinting.
