Heating Session
- Three heating sessions with varied temperature is helpful. Three heating sessions can be obtained by changing the coil density.
- Heating session-2 is in the middle of the heating tube. The temperature on the session-2 should be at a point where the plastic can be totally melted in the session-2.
- Heating session-1 is on the feeding side and heating session-3 is on the extrusion side. The temperatures on session-1 and session-3 should be slightly lower than that on session-2 (Pettit, 1973). Heating session-1 is for pre-heating the plastic. Plastic after heating session-3 should have enough viscosity to form filament, and the viscosity is varied with temperature for the same plastic.
- The temperature on nozzle should be close to the temperature on heating session-3. It is important to keep the nozzle with a stable temperature because nozzle is easy to lose heat.