Polyethylene terephthalate (PET): melt temperature, drying, shrinkage
Typical values for Polyethylene terephthalate (PET, semi-crystalline) in injection moulding: melt temperature 270–285 °C, mould temperature 90–120 °C, shrinkage 1.2–2.0 %, drying: 4 h at 160 °C. The processing window below shows melt and mould temperature on one scale; the app covers more than 150 materials.
Processing window
PET Polyethylene terephthalate, semi-crystalline
Melt temperature 270–285 °C
Mould temperature 90–120 °C
- Drying
- 4 h at 160 °C
- Density
- 1.38 g/cm³
- Cavity pressure
- 400–850 bar
- Shrinkage
- 1.2–2.0 %
Typical values for standard grades from the Resinovo material guide. They do not replace the manufacturer’s datasheet.
PET at a glance
PET is semi-crystalline, stiff and has a good gas barrier. In injection moulding it is mainly used for bottle preforms and technical parts; recycled PET is widespread.
PET has to be dried very thoroughly, otherwise the viscosity drops through hydrolysis. Crystalline parts need a high mould temperature.
Processing data for PET
- Melt temperature: 270–285 °C
- Mould temperature: 90–120 °C
- Drying: 4 h at 160 °C
- Density: 1.38 g/cm³
- Cavity pressure: 400–850 bar
- Processing shrinkage: 1.2–2.0 %
All values are typical figures for preselection. The manufacturer’s datasheet applies to the specific grade, and sampling on the machine decides the process.
Frequently asked questions
What processing temperature does PET have?
The melt temperature for Polyethylene terephthalate is 270–285 °C and the mould temperature 90–120 °C (typical values).
Does PET have to be dried before processing?
Yes. Typical value for Polyethylene terephthalate: 4 h at 160 °C. The manufacturer’s datasheet for the grade in use is what counts.
How high is the shrinkage of PET?
The processing shrinkage of Polyethylene terephthalate is 1.2–2.0 %. It depends on wall thickness, holding pressure, mould temperature and grade.
What cavity pressure applies to PET?
The range for Polyethylene terephthalate is 400–850 bar. The clamping force calculator and the app start with the mean of 625 bar; you can adjust the value.
More on PET in the app
All properties
Flow behaviour, MVR and MFR, thermal conductivity, heat deflection, mechanical properties, fire rating and processing notes.
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Density, cavity pressure and temperatures feed straight into the calculators and ResiCheck.
Read on
- Clamping force calculator
- Shot volume calculator
- Cooling time calculation
- Injection moulding defects: causes and remedies
- Material guide: all values at a glance
More materials: PP · HDPE · ABS · ASA · PA6 · PA66 · POM · PMMA · PC · PC/ABS · PBT · PS · SAN · TPU · PEEK · PPS · PP-GF
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