We test per IPC TM 650 2.4.24.1.

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This test is used to determine the thermal reliability during assembly and rework processes of PWBs. In addition, it can be used to down select laminate choices for a given application. The information obtained from this test is typically more useful than the Tg test alone can provide in helping to choose the correct material.

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In this test, the sample is enclosed in a furnace chamber where the temperature is controlled to ramp at 10°C per minute to preset isotherm and then stays at temperature for set time. When an event occurs, cracking, moisture release, stress relaxation, or decomposition, a sudden movement of the sample surface will be detected.