 In using solder paste for circuit assemblies, one needs to test and understand the various rheological properties of a solder paste.Solder paste is typically used in a stencil-printing process by a solder paste printer, in which paste is deposited over a stainless steel or polyester mask to create the desired pattern on a printed circuit board.The paste may be dispensed pneumatically, by pin transfer (where a grid of pins is dipped in solder paste and then applied to the board), or by jet printing (where the paste is sprayed on the pads through nozzles, like an inkjet printer).