The feeder for starch was calibrated and set at a particular speed. The other feeder/feeders were calibrated and set
at feeding rates accordingly. Initially, during start-up, water is pumped into the system immediately after the feed throat, at
15-20% of the starch fed, and later its flow rate is reduced to about 8-10% of starch. The inherent moisture present in starch
also aids in plasticization of starch. The different parameters were varied one at a time while the other parameters remained
those of the basic setting. When formulations were changed, extrusion was continued until the torque and the die pressure
stabilized. Extrusions were carried out at a torque of 70-75%, and a pressure of 700-1000 psi. The loose-fill were extruded
at a rate of about 10-15 lb/hr (4.5-6 kg/hr), while the foam sheets were extruded at a throughput of 900-920 lb/hr (405-420
kg/hr).