Thermal Interface Material (TIM) Testing Service
Thermal Impedance & Conductivity Measurement – ASTM D5470 Based

Our Thermal Interface Material Testing Service includes the measurement of thermal impedance and conductivity of Thermal Interface Materials (TIM). Thermal impedance and conductivity are two major properties of TIMs. Although their values can be found on manufacturers’ datasheets, these values are often measured based on different standards (e.g, ASTM D5470, ASTM C-177, etc.) or under different test conditions (e.g, environment, contact pressure, etc.). In our thermal laboratory, we can help customers characterize the thermal impedance and thermal conductivity values based on ASTM D5470 standard under specified test conditions. We can provide a side-by-side comparison of several TIMs under the exact same test conditions. To do this, we use LongWin’s LW-9389 TIM Thermal Interface Material Tester, which is used by many TIM manufacturers worldwide to characterize materials. For more information about the basics of TIMs, please visit our Thermal Interface Materials Basics page.
What Can Be Tested for Thermal Interface Material Testing and How Accurate?

- Thermal Grease
- Gap Filler Pads
- Phase Change Materials (PCM)
- Thermal Tapes
- Graphite Sheets
- Thermally Conductive Insulators
- Ceramics
- Metals
- Plastics
- Printed Circuit Boards (PCB)
- Metal Core PCB (MCPCB)
- Metal-based Copper Clad Laminates (MCCL)
- Thermal Impedance
- Thermal Conductivity
- Contact Impedance
- Pad Deflection
- Thermal Impedance: > 0.01 °C-cm²/W
- Thermal Conductivity: < 20 W/m-°C
- Accuracy: ±5%.

Features of LW-9389 TIM Thermal Impedance & Conductivity Tester

- Based on ASTM D5470
- Good repeatability and reproducibility
- Suitable for measuring thermal impedance and conductivity of grease and pad
- Automated setting of press load and input power
- Automated setting of temperatures of hot surface, cold surface and average temperature
- Suitable for reliability tests
- Automated DAQ and output in Excel
Specifications
- Press Load Range: 4 ~ 50 kgf
- Max. Heating Power: 160 W
- Max. Heating Temperature: 180℃
- Constant Temperature Range: Ambient+3℃~50℃
- Overall Dimension: 1.37 (W) × 0.87 (D) × 1.88 (H) m (Ref.)
- Power Source: AC220V, 10 Amp, Single Phase
Methodology of Our Thermal Interface Material Testing
The test is performed based on ASTM D5470:
Calculation of Thermal Conductivity and Contact Impedance:
In ASTM D5470-06 standard, the linear correlation of thermal impedance and thickness are measured based on one specimen with three different thicknesses. The values are extrapolated with the thickness set to zero, which is contact impedance. The thermal conductivity, also known as apparent thermal conductivity, can be found by taking the reciprocal of the slope.
Example of Software Interface – Pad/Grease Impedance Test:
