Thermogravimetric Analysis of Flux Solvent Evaporation in Reflow Profiles
Thermogravimetric solvent mass loss below half a percent prior to liquidus eliminates outgassing macro-voids under bottom-terminated components.
Weight Loss Kinetics
Evaporation Mechanics
Thermal analysis methods measure the rate at which organic compounds change from liquid or solid to gas as temperature rises. Quantifying the weight loss kinetics of a paste during heating allows process engineers to optimize preheat zones, preventing problems such as voiding and spattering in the reflow stage. This tracking measures the change in mass of the solder paste over a defined temperature ramp.
Dynamic Measurement
Dynamic heat cycles in analytical instruments mimic the conditions within a high-speed production oven. The weight loss kinetics of a paste show how much solvent is released before the metal alloy begins to melt. If too much of the organic vehicle remains, it can become trapped in the molten metal, forming large voids that weaken the joint.
Process engineers use this data to select the best heating rates and oven speeds for the production line.
Material Validation
Materials must undergo testing to verify that their decomposition profiles match the capabilities of standard reflow ovens. Analyzing the weight loss kinetics helps chemists design solder pastes that dry at the correct rate. When the paste exhibits a stable drying phase, the resulting joint has fewer voids and a smoother surface.
This analysis is critical when testing new lead-free paste formulations that require higher processing temperatures. By understanding these thermal kinetics, manufacturers can prevent many common defect types before production begins.