Fluid Behavior
Viscosity in certain conductive pastes changes depending on the rate of shear applied during the application process. Non-newtonian infill mechanics govern how these materials flow into small holes and recesses on a circuit board during the manufacturing cycle. When the squeegee moves across the stencil, the high shear stress reduces the viscosity, allowing the paste to enter the via.
Once the stress is removed, the material thickens again to stay in place, ensuring that it does not leak out before the curing stage.
Filling Process
Successful encapsulation of through-holes requires the material to reach the bottom of the cavity without trapping air. Under the rules of non-newtonian infill mechanics, the speed of the application tool must be carefully matched to the properties of the paste. If the tool moves too slowly, the material remains too thick to fill the hole completely.
Structural Integrity
Once the filling material is cured, it must provide a stable base for subsequent plating steps. The study of non-newtonian infill mechanics helps manufacturers formulate pastes that do not shrink or crack during the heating cycle. Proper filling prevents the formation of voids that could lead to electrical failure.
Reliable infill is necessary for the production of high-density interconnect boards.
