Cellink 000000020356, Руководство пользователя

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25
04 Getting started
4.6 Pneumatic Printhead printing optimization
The Pneumatic Printhead uses compressed air to extrude bioink through a nozzle or needle
with diameters between 50 and 600 micrometers. As a result, you can increase or decrease
the air pressure to control the filament dispensing rate. Parameters that affect the deposited
material’s diameter include nozzle diameter, translation speed, layer height, bioink chemistry
and thermal environment. Bioinks should be characterized thoroughly to determine the
optimal parameters for the Pneumatic Printhead.
It is necessary to control the applied pressure to maintain viability while bioprinting. High
pressure and small nozzle diameters can produce excessive shear stress that results in cell
damage or rupture. Pneumatic-based extrusion systems enable users to control the pressure
within the cartridge and the resulting cell viability. However, pneumatic-based extrusion
systems offer less control over the flow rate and filament diameter.
The diameter of a filament extruded by the Pneumatic Printhead depends on nozzle diameter,
applied pressure, temperature and translation speed of the printhead. These factors will affect
the resulting filament diameter. As the applied pressure increases, the resulting filament
diameter will increase. Similarly, as the translation rate is increased, the resulting filament
diameter will decrease – and resulting filaments will be noncontinuous and nonuniform.
In balanced conditions, the resulting diameter will approach the diameter of the nozzle or
needle used. Adjusting the temperature of the printhead and applying pressure might result in
changes to the bioink viscosity depending on its rheological behavior.