Extruder output rate calculation

During extrusion blow moulding of 60 nun diameter bottles the extruder output rate is 46 X 10 m /s. If the die diameter is 30 mm and the die gap is 1.5 mm calculate the wall thickness of the bottles which are produced. The flow curves in Fig. 5.3 should be used. 

It is desired to blow mould a cylindrical plastic container of diameter 100 mm and wall thickness 2.5 rtmi. If the extruder die has an average diameter of 40 mm and a gap of 2 nun, calculate the output rate needed from the extruder. Comment on the suitability of an inflation pressure in the region of 0.4 MN/m. The density of the molten plastic may be taken as 790 kg/m. Use the flow curves in Fig. 5.3. 

From this simple mass balance it is easy to see which factors are important in determining the output of an extruder screw and for the calculation of a screw s performance. In addition the melting area can be broken down into several areas such as against the barrel, along the screw flights and the screw root and the melting rate for each of these sections added to the overall melting rate. 

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