Solder Paste Printing

Volume Consistency

Repeatable deposit sizes rely on maintaining uniform rheological properties within the alloy mixture while controlling the pressure applied by the squeegee blades. Temperature fluctuations alter the viscosity of the carrier flux which changes the release characteristics from the stencil walls. Cleaning cycles remove residual alloy from the underside of the stencil to prevent smearing and bridging between adjacent pads.

High-speed cameras monitor these stencil wiping intervals to ensure that debris does not accumulate and compromise the sharpness of the printed edges.

Registration Accuracy

Correct alignment between the board fiducial markers and the stencil apertures ensures that the deposited paste centers perfectly on the intended copper pads. Misalignment forces the alloy off the pad area which produces irregular fillet shapes or creates short circuits between neighboring pads. Mechanical tensioning systems hold the stencil flat against the substrate to prevent the alloy from bleeding under the mask during the stroke.

Fixed tolerances define the allowable shift in placement before the machine flags an error or halts production. Proper calibration of the vision system minimizes these position offsets over long production runs. Small variances in board flatness require adaptive support structures to maintain a consistent gap between the stencil and the circuit surface.

Stable contact pressure remains the primary factor for achieving reliable transfer efficiency across high density arrays.