Heatsink Clip Load Metrology
44 Thermal and Mechanical Design Guidelines
Table 5. Typical Test Equipment 7. Item 18. Description
9
. Part Number
(Model)
20. Load
cell
21. Notes:
1, 5
22. Honeywell*-Sensotec* Model 13
subminiature load cells, compression
only
23. Select a load range depending on load
level being tested.
24. www.sensotec.com
25. AL322BL
26. Data
Logger
(or
scanner
)
27. Notes:
2, 3, 4
28. Vishay* Measurements Group Model
6100 scanner with a 6010A strain card
(one card required per channel).
29. Model 6100
30. Clip
Force
Measure
ment
machine
31. Notes:
644
32. Customized machine that houses load
cell for force measurement. Top side
plate can be modified to accommodate
various attach pattern
33. CFM-001 (Cool
Star
Technology)
NOTES:
1. Select load range depending on expected load level. It is usually better, whenever
possible, to operate in the high end of the load cell capability. Check with your load cell
vendor for further information.
2. Since the load cells are calibrated in terms of mV/V, a data logger or scanner is
required to supply 5 volts DC excitation and read the mV response. An
automated model will take the sensitivity calibration of the load cells and convert the
mV output into pounds.
3. With the test equipment listed above, it is possible to automate data recording and
control with a 6101-PCI card (GPIB) added to the scanner, allowing it to be connected
to a PC running LabVIEW* or Vishay's StrainSmart* software.
4. IMPORTANT: In addition to just a zeroing of the force reading at no applied load, it is
important to calibrate the load cells against known loads. Load cells tend to drift.
Contact your load cell vendor for calibration tools and procedure information.
5. When measuring loads under thermal stress (bake for example), load cell thermal
capability must be checked, and the test setup must integrate any hardware used along
with the load cell. For example, the Model 13 load cells are temperature compensated
up to 71°C, as long as the compensation package (spliced into the load cell's wiring) is
also placed in the temperature chamber. The load cells can handle up to 121 °C
(operating), but their uncertainty increases according to 0.02% rdg/°F.
6. Clip force measurement machine is recommended to be calibrated before usage.
Standard weights should be used to check for preload cell accuracy and consistency.