Injection Temperature Calculator
Determine the actual melt temperature accounting for shear heating generated by the screw and the effect of back pressure. Melt temperature affects part quality, cycle time, and material degradation.
Input Parameters
Results
Fill in the data and click Calculate
ARGUS monitors melt temperature in real time and alerts before degradation occurs
The actual melt temperature can differ from the set value by as much as 20–30°C — ARGUS accounts for shear heating and corrects parameters automatically.
How do we calculate the actual melt temperature?
The actual melt temperature is the sum of the barrel set temperature and the shear heating generated by screw rotation. Shear heating arises from internal friction in the polymer melt during plasticization and can raise the material temperature by 5–30°C above the set value.
The calculator estimates the temperature rise due to shear heating based on screw speed and back pressure. Higher speed and higher back pressure generate more shear heat.
ΔTshear = f(RPM, pback)
Tbarrel — barrel temperature [°C]
ΔTshear — temperature rise from shear heating [°C]
RPM — screw speed [rev/min]
pback — back pressure [bar]
Shear heating is especially significant for thermally sensitive materials (PVC, POM, PC) and at high plasticizing speeds. Excessive shear heating leads to thermal degradation — breakdown of polymer chains, discoloration, deterioration of mechanical properties, and outgassing.
Melt Temperature Control
Measuring the actual melt temperature is critical for process quality control:
Hand pyrometer — measures the melt strand after it exits the nozzle
Needle thermocouple — measures inside the melt bulk (most accurate)
Back pressure affects melt homogeneity and the amount of shear heating. Higher back pressure improves mixing but increases shear heating and plasticizing time. Typical values: 30–80 bar for standard materials, 50–150 bar for colored or filled grades.
Temperature Optimization
The barrel temperature profile should increase from the hopper to the nozzle (ascending profile) for most materials. Exceptions: PVC and POM require a descending or flat profile. Material residence time in the barrel should not exceed 5–8 minutes — longer times increase the risk of degradation.
ARGUS monitors melt temperature and automatically optimizes the temperature profile
See it for yourself — book a presentation and see how ARGUS combines temperature control with full process context.