IPC Slash Sheet Laminate Selection Principles
IPC-4101 slash sheets establish mandatory baseline physical, thermal, and electrical limits that override generic trade names to enforce material reliability.
T288 Test
Delamination Profile
IPC-TM-650 Method 2.4.24.1 specifies thermomechanical analysis procedures for evaluating delamination resistance of printed circuit board laminates at elevated temperatures. The T288 test measures the time required for a copper-clad or unclad laminate to undergo internal structural separation when held at a constant temperature of 288 degrees Celsius. This isothermal test evaluates substrate endurance under severe thermal stresses typical of multiple lead-free reflow cycles or wave soldering operations.
Thermal expansion transducers detect z-axis dimensional jumps that signify internal resin-glass interface separation or copper foil debonding. Laminate materials with superior thermal stability exhibit longer endurance times before structural failure occurs. Specimen preparation requires precise dimensioning and surface cleaning to eliminate edge artifacts during expansion recording.
Thermomechanical Response
Thermomechanical analyzers apply a constant mechanical load while maintaining isothermal conditions. Resin breakdown generates gaseous volatile compounds that build internal pressure within the laminate core. Sudden slope changes in the expansion curve pinpoint the exact moment of physical delamination.
Acceptance Threshold
High-reliability aerospace and automotive specifications require minimum T288 survival times exceeding fifteen minutes. Printed circuit board coupons undergo thermal conditioning prior to testing to drive out absorbed moisture. Failure before minimum threshold times invalidates the material lot for production assembly.