14. A glass fiber/polymer compound is injection molded in a steel tool. To simplify the analysis, assume treat is as it is only polymer and model the sprue, runner and part as a cylinder of diameter 10 mm and length 150 mm. Determine the injection pressure to make the part in 2 seconds (4pts) Data given: Polymer density =980 kg/m^3, polymer viscosity (u)=10^3 N-s/m^3, barrel diameter (D) = 28mm, flight width (w) = 21 mm, flight height (H) = 4 mm, helix angle (q) = 15 degrees, length of screw (L) = 1.25 m 9 v.B B dp R Q= |2rudr AR Q=QD-Qp=1 W 2 12 dz + 8L f(screw speed) f(pressure drop) P d d 2t 4t F ejection = upA HEAAT F ejection d d 2t 4t