7- Liquid State Deposition/ (Manufacturing Technique)
(Previous/Better)
The material is heated into
the melt regime and deposited in a pattern by various techniques.
a. A filament of thermoplastic polymer or wax is heated and extruded through a
nozzle, the movement of which is controlled in x-y coordinates. The table drops
when a layer is completed. Rapid solidification gives sufficient strength to
obviate the need for outside support.
b. By spraying through masks cut out by laser, a shaped part can be built up
in layers. In a variant, a laser beam is directed through the center of a
powder-delivery nozzle; thus, the part is built directly from fused layers.
c. When the platform (or the nozzle) is given a programme a z-axis movement,
3-D shapes can be built up directly by the coil-building method. The part may
also be built as a continuous weld bead. Surface quality will have to improve
before these processes can be used for functional parts.
(Schey John A.,
Introduction to Manufacturing Processes 3rd Edition, p.801)
(New)
For the case of liquid-state
deposition, methods that directly result in patterned films are frequently
summarized under the term “printing”, although several techniques have been
developed, which do not belong to the traditional printing methods.
Therefore, liquid state
processing, unlike the usage of flexible substrates is not a strict
prerequisite for roll-to-roll processing. However, the application of high
volume liquid state coating and printing technologies enables the exploitation of
advantages of roll-to-roll deposition techniques.
(C. J. Brabec, V. Dyakonov, U. Scherf, Organic photovoltaics: materials,
device physics, and Manufacturing Technologies, pp. 513-514)
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