Important Stages of the Production Process - Introduction to Polymeric Composites with Rice Hulls - page 100

• Turn all heaters off and keep barrel cooling on maximum.
• Open the extrusion head, remove and clean the die and the head. A light coating
of silicone grease can be applied.
• When the machine is cool, turn off the water supply and main power.
If the extruder is to be left full at the time of shutdown, e.g., using LDPE:
• Lower temperature settings on the barrel.
• Leave the die heaters on.
• Put the barrel cooling on maximum.
• Pump material through the machine while it is cooling.
• When the material coming out is relatively cool, close the hopper gate.
• Keep reducing the screw speed slowly to zero.
• Put barrel cooling onto the automatic setting and ensure that the water cooling
is on.
• Turn off the water cooling.
• To restart, follow the warm-up procedures as set out above.
These recommendations are, in general, based on the standard processing of polymer
resins but will be more or less the same for processing PCRH. However, a producer
will have to work out parameters and procedures which are best for his/her operation.
The suppliers of machinery will provide vital information on the technicalities of each
machine and in most cases work with the buyers with regard to installation and the
initial production trials. An advantage in the processing of polymer composites is
that a producer will buy customised machinery to suit the operation.