How to read a material technical data sheet
A technical data sheet (TDS) contains a material's key parameters; knowing how to read these figures correctly helps engineers compare products objectively and choose the material that fits the real-world application.
Every adhesive, tape or thermal material code comes with a TDS of two to six pages. However, many people look only at a few headline numbers and overlook the test conditions, leading to incorrect comparisons between manufacturers.
The typical structure of a TDS
- Product description and recommended applications.
- Uncured material properties: viscosity, density, mix ratio, working time.
- Cure conditions: temperature, time, UV energy or humidity.
- Cured properties: mechanical, thermal, electrical.
- Directions for use, storage and shelf life.
Key parameters and how to interpret them
| Parameter | Unit | What to watch for |
|---|---|---|
| Viscosity | mPa·s or cP | Depends on temperature and spindle speed during measurement |
| Working time | minutes | Usually measured on a small sample mass at 25 °C |
| Lap shear strength | MPa | Note the substrate and bond line thickness |
| Glass transition temperature Tg | °C | Above Tg the material softens and mechanical properties drop |
| Thermal conductivity | W/m·K | Different test methods give different results |
| Dielectric strength | kV/mm | Depends on specimen thickness |
Pitfalls when comparing
Two products both listing a thermal conductivity of 3 W/m·K can differ greatly if one manufacturer measures per ASTM D5470 and the other uses the hot disk method. Lap shear strength on grit-blasted aluminum cannot be compared directly with strength on galvanized steel. In addition, many TDSs list typical values rather than guaranteed values; guaranteed values appear in the specification used for lot inspection.
Look for what the TDS does not say
- Performance after damp heat aging if the TDS lists only initial values.
- Compatibility with your specific substrates.
- Processability on the equipment the plant already has.
From TDS to material selection
The TDS is the starting point for narrowing down the list, but the final decision should be based on testing with real parts under real production conditions.
An effective approach is to build an internal comparison table that includes only the parameters that truly affect your application, together with the corresponding test methods. This table helps purchasing and engineering evaluate suppliers against the same set of criteria.
Contact AMS Vietnam if you need an engineer to help read and compare TDSs across material manufacturers.
