Question $5$

You are tasked with optimising the processing conditions for a polymer ink. The ink

displays non$-$newtonian flow behaviour, and a plot shear stress versus shear strain

indicates power$-$law behaviour $(K=5$ Pa$.$s$,n=0\mathrm{.}81).$ Estimate the pressure that must be

applied to the ink to achieve a volumetric extrusion rate of $0\mathrm{.}5m\frac{m^3}{s}$ during printing. The

nozzle has a radius of $250$ mic ans and a length of $5$ mm $.$

$10130$ Pa

$4220$Pa

$3760$ Pa

$8914$ Pa