Quick3D Vicat softening temperature
Vicat softening temperature is where a loaded needle sinks into a heated plastic. Learn how it differs from HDT and how to read it.
What it means in practice
The Vicat softening temperature is the point at which a plastic’s surface becomes soft enough for a small, flat needle to push into it. It describes local softening, not bending.
Key takeaways
- Vicat is the temperature at which a small flat needle sinks 1 mm into a heated plastic.
- It describes local surface softening, not bending under load.
- Vicat usually reads higher than HDT, so never compare one with the other.
- Check the method: the 10 N and 50 N loads give different readings.
It is useful for parts where something presses into a small area while hot:
- Clips and mounts that clamp a hot pipe or cable.
- Feet and pads under warm equipment.
- Parts with heat-set inserts or screws that could sink or loosen.
- Comparing grades of the same polymer, where it gives a quick, repeatable ranking.
How it’s measured
A flat-ended needle with a 1 mm² tip rests on the sample under a set force. The sample is heated at a steady rate. The temperature is recorded when the needle has sunk 1 mm.
- Standards: ISO 306 and ASTM D1525.
- Methods: the load is 10 N (method A) or 50 N (method B). Heating is 50 °C or 120 °C per hour. ISO codes such as A50 or B120 combine the two.
- Units: °C.
Method A (10 N)
The lighter load. It gives the higher reading for the same material.
Method B (50 N)
The heavier load. It gives a lower reading. Compare A with A and B with B.
How to read and compare it
- Check the method. The 10 N load gives a higher reading than the 50 N load for the same material. Compare A with A and B with B.
- Vicat is usually higher than HDT. The needle test barely loads the material, while HDT bends a whole bar. Never compare a Vicat value from one material with an HDT value from another.
- Not a service temperature. At the Vicat point, the plastic is already soft. Design to stay well below it.
- Sample origin. Some values come from moulded plaques of the base polymer, not printed parts.
- Coverage. In our catalog, Vicat is reported mostly for filaments and powders. Few resin sheets include it.
Range in our catalog
- All materials: 27–272.5 °C (median 98 °C, 129 materials)
- Filaments: 27–272.5 °C (median 95.5 °C, 96 materials)
- Powders (SLS and MJF): 94.3–193 °C (median 175 °C, 17 materials)
- Standard materials: 56.9–104 °C (median 66 °C, 25 materials)
- Engineering materials: 58–238.4 °C (median 117 °C, 69 materials)
- PLA 1756.9–156.2
- PETG 1070–86
- ABS 1078–127.4
- ASA 496–110.8
- PC 6116–176
- PA12 4145–171
- PEI 4173–210
Bar = lowest to highest, dot = median. 55 materials, live from our database.
Good to know
Each bar mixes methods A and B, and some values come from moulded plaques rather than prints. Treat it as a rough ranking.
Highest and lowest in our catalog
Highest Vicat
| Material | Polymer | Vicat softening temperature |
|---|---|---|
| Fiberon PPS-GF20 | PPS | 272.5 °C |
| Kexcelled THE K10 PPS CF10 | PPS | 269 °C |
| Fiberon PPS-CF10 | PPS | 267.5 °C |
| Fiberon PET-CF17 | PET | 238.4 °C |
| Kexcelled THE K11 PPSU | PPSU | 220 °C |
Lowest Vicat
| Material | Polymer | Vicat softening temperature |
|---|---|---|
| Ultrafuse TPU 95A | TPU | <27 °C |
| Ultrafuse TPU 85A | TPU | 35 °C |
| Ultrafuse TPU 64D | TPU | 48 °C |
| Ultrafuse PLA | PLA | 56.9 °C |
| Ultrafuse PLA Pro1 | PLA | 58 °C |
Related properties
- Heat deflection temperature — softening under a bending load.
- Glass transition temperature — the underlying change from rigid to rubbery.
- Melting temperature — the upper limit for semi-crystalline plastics.
- Shore hardness — another indentation test, at room temperature.
See high-temperature materials 128 materials