Case Study Examples
Temperature-Dependent TIM Testing
This study was conducted on four TIMs to determine temperature dependent impedance characteristics. Each material was mounted and tested at six temperatures using the Temperature Batch feature. The TIM Tester 1400 was used here since temperatures needed were higher than those available with the TIM 1300. The temperature parameter here is the average temperature across the sample in accordance with the definition of "sample temperature" as detailed in ASTM 5470. All of the data shown here was collected with only four batch tests: one test for each material and with six sample temperature commands per batch.
Thermal Impedance Versus Pressure and Load Cycle
This study was conducted on a TIM that experienced a non-recoverable compression that improved it's thermal properties. Once compressed, the pressure dependent-thermal impedance was stable and repeatable. Many types of TIMs experience this sort of improvement. Sustained pressure and temperature often cause the surface contact interfaces to progressively " wet" thereby expelling entrained air within the surface contact interface region which reduces the thermal contact interface resistance.
Determination of Bulk Thermal Conductivity of Thermal Grease
This study was conducted on a grease (type I material) TIM to determine it's bulk thermal conductivity. Tests of this sort can exhibit some data-scatter due to small voids in the grease as well as small uncontrolled irregularities in the contour of the edge of the grease layer. The recommended techniques for performing this type of testing with the TIM Tester 1300 or 1400 are very effective for taming data-scatter from these effects. All TIM Tester data is automatically appended with estimated accuracy tolerances in data files and data plots as shown below.
High Conductivity Measurement
This study was conducted on a sample of metalic iron (type III material) to determine the bulk material conductivity and the contact interface resistance. For this test, three precision ground samples were prepared and tested with surface contact interface abatement. There is no upper or lower limit on the conductivity values that can be be measured with the TIM 1300 and 1400 although for materials with conductivity greater than 100 W/mK, there is a lower limit on the thickness of the samples that can be accurately tested.