Are there enough solder paste infront of the squeegee (app. 15 mm radius roll).
Does previous solder paste stick to squeegee?
Does the solder paste infront of squeegee drag instead of rolling?
Does the solder paste stay on the stencil surface?
Are apertures less than half of the pitch size?
Is the stencil thicker than 0.150 mm?
Are apertures clogging?
Is stencil deformed?
Is the green dye thicker or thinner than the pads?
Are ther any solder masks, stickers and etc. near misprinted?
Are tin coated pads smooth?
Is the viscosity of the solder paste too much?
Is solder paste old and dry?
Is the solder paste left on the stencil more than tens of minutes ?
Is it cold in printing area?
Is it uniform at squeegee edges?
Is squeegee blunt?
Are squeegee edges damaged?
Is squueegee speed too much for solder paste?
Is squueegee pressure too low? (for example less than 1kg/100mm squeegee length )
Are PCB supports weak?
Is squeegee too soft (less than 75 shores)
Is squeegee pressure to high? (for example more than 2kg/100mm through squeegee length).
Is seperation speed less than 0.5 mm/s or more than 10 mm/s?