Why Is Board Support Necessary in the Lead-free Process?

Aside from the fact that higher temperatures through the reflow process will induce PCB warpage, bottom-side support becomes a key factor when considering the requirement for “complete gasketing” of the board to stencil when using lead-free pastes. Variations in the planarity of the PCB during the print are an open invitation for bridging and other similar print defects that are more common in the lead-free environment.