Reversed temperature profile 1
Vol.21 #1, June 1994
Many of the latest barrier screw designs work best with either reverse or humped profiles to achieve optimum melting and pumping performance. If the temperatures on the first few zones are set too low, you will sometimes see small gels, or unmelted particles in the extrudate.
If the rate seems too low, try raising the set points on zones 2 and 3 above the set points of the other zones (to form a hump in the profile). This will often improve feeding and, therefore, the rate. If the melt temperature is too high, lower the settings on the last zone(s).
See also:
- Lower feed zone temperature
- Melt block problems
- Reversed temperature profile 2
- Screw design
- Vent bleed
Return to
Extrusion Hints