Thermal Accumulation
Solder paste on a stencil increases in temperature due to the friction generated by the continuous motion of the squeegee during board production. Analyzing paste roll heating dynamics helps engineers understand why paste might lose its required thickness or begin to stick to the foil over time. It measures the heat transferred from the high-speed mechanical motion into the chemical flux system.
Material Degradation
Heat changes the evaporation rates of the volatile solvents that keep the paste in a printable state. As temperatures rise, the flux vehicle thins out too early, potentially causing the solder particles to slump or the paste to dry out inside the screen apertures. This process alters the printing reliability if the equipment is not housed in a temperature-controlled environment.
Effective cooling strategies focus on managing the ambient air or using specialized squeegees that dissipate thermal energy more quickly.
Operating Windows
Stability in the paste properties is only achievable when the rolling temperature remains within a range of roughly five degrees. Monitoring sensors track the shift in temperature at the point of contact to prevent the materials from crossing the threshold into chemical instability. A failure to manage this dynamic results in erratic volume deposits across the board panel.
