It is important to have adequate controlled
heating of the die adapters and connecting flanges. With unheated
flanges, so much heat may be dissipated that the temperature in
this area drops too heavily.
channels must be designed so as to encourage good flow (i.e.
without any dead spots), and the cross section should be geared to
the mass flow rate. For the same reason, leaps in pressure must be
avoided at all costs.
In long adapters,
static mixers have proved useful for maintaining transverse mixing
as they ensure greater uniformity of temperature and color
dispersion in the melt. The use of strainer disks with and without
a screen pack is of course also a possibility (Fig.
|Fig. 1: Example of a strainer
disk with a screen pack