Prepreg Melt Viscosity Dynamic Range during Thin Core Lamination Profiles
Matching prepreg melt viscosity minima to press pressure ramps prevents thin-core distortion and resin starvation in high-density multilayer lamination.
Specific Press Pressure
Applied Force
Hydraulic tonnage divided by the surface area of a print head represents the force distribution during screen printing. Specific press pressure ensures that solder paste transfer remains uniform across the aperture patterns of a stencil. Variations in this force lead to either an accumulation of paste on the board surface or an incomplete fill of the stencil openings.
Excess force causes stencil deflection while insufficient force creates gaps in the volume deposited on the pads.
Transfer Calibration
Machine operators establish this parameter based on the viscosity of the solder paste and the aperture geometry of the stencil. High viscosity materials require higher levels to overcome the resistance of the mesh and the stencil thickness. Precise control prevents the smearing of paste that occurs when a head travels with incorrect downward tension.
Stable values prevent damage to the squeegee edge and prolong the lifespan of the metal stencil.
Process Verification
Pressure sensors integrated into the print head provide real time feedback to the motion controller to maintain target levels throughout the stroke. This measurement validates that the head remains flat against the stencil surface during the entire length of the print pass. Inspection stations perform volume checks on the deposited paste to confirm that the selected setting yields the correct height and alignment required for reliable component attachment.
Consistent adherence to these values prevents batch failure during the subsequent reflow stage.