Dynamic Squeeze Flow Hydrodynamics across Ultra Smooth Circuit Foil Interfaces
Dynamic resin squeeze flow across ultra smooth copper foils demands precise thermal press ramping to prevent micro-voiding and hold tightly controlled plane spacing.
IPC-TM-650 Method 2.4.38
Testing Protocol
Standardized test procedures for determining the glass transition temperature of printed board materials provide the necessary data for thermal mechanical analysis. Quality technicians follow ipc-tm-650 method 2.4.38 to measure the dimensional changes of a specimen as it is heated through its transition range. Transitions are identified.
This method provides a reliable way to identify the point where the resin shifts from a hard state to a more pliable one.
Mechanical Stability
Expansion rates change drastically once a material reaches its transition temperature. Testing reveals that expansion rates change drastically once a material is evaluated by ipc-tm-650 method 2.4.38 protocols.
Laminates
Substrates must be characterized to ensure they can survive the thermal shocks of the assembly line. By applying ipc-tm-650 method 2.4.38, manufacturers determine the safe operating window for reflow and wave soldering. The test involves placing a small sample under a weighted probe that detects the exact moment the coefficient of thermal expansion increases.
This measurement is critical for preventing via cracking and barrel fatigue in high aspect ratio boards. If the transition temperature is too low, the Z axis expansion of the board may exceed the ductility limits of the copper plating. Engineers use this data to select materials that match the thermal demands of the final product environment.
Reliability depends on this measurement.