HANSER Hanser Publishers, Munich • Hanser Gardner Publications ...
HANSER Hanser Publishers, Munich • Hanser Gardner Publications ...
HANSER Hanser Publishers, Munich • Hanser Gardner Publications ...
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The profiles of stock temperature and pressure can be calculated from the melting profile<br />
by using the width of the melt-filled part of the channel in the equations given in<br />
Section 5.2.2 [10].<br />
5.2.4 Temperature Fluctuation of Melt<br />
Temperature and pressure variations of the melt in an extruder serve as a measure for the<br />
quality of the extrudate and provide information as to the performance of the screw.<br />
The temperature variation AT may be estimated from the following empirical relation,<br />
which was developed from the results of SQUIRES' experiments [12] conducted with 3-zone<br />
screws:<br />
This relation is valid for 0.1 K NQ < 0.5.<br />
The parameter NQ is given by<br />
where<br />
AT= temperature variation ( 0 C)<br />
Dh = barrel diameter (cm)<br />
G = extruder output (g/s)<br />
L = length of screw zone in diameters<br />
H - depth of the screw zone (cm)<br />
Example<br />
Following values are given:<br />
Dh - 6 cm<br />
G = 15 g/s<br />
(5.62)<br />
(5.63)