17 Jan 2024 Slumping
Refers to the sinking and bleeding out of the paste from the original print geometry during stencil or screen printing. The paste is pulled between the stencil and the product. This results in blurred edges of the printed image and the layer thickness is reduced compared to the stencil thickness. This printing error has a major influence on the final layer thickness after soldering or sintering and should therefore be rectified.
This can be caused by the composition of the paste (particle size and shape), as well as by the product carrier and print settings. A gap between the printing surface and the stencil promotes paste leakage, as does excessive squeegee pressure.