Combined Jet Printed and Screen Printed Solder Paste Deposit - Evaluation of Results

The article presents the first results obtained from modified SMT (surface mount technology) assemblies with the application of PiP (Pin in Paste). The modification consists of the use of a combined footprint, consisting of two types of solder pastes (standard and low temperature) in one footprint. It can be applied using screen printing and jet printing. The aim is to use the entire amount of applied solder paste in the area of the pads and holes when over printing is used (applying paste on the solder mask) and to improve the conditions for obtaining quality assembly. The experiments were performed using a printer and a two-head jet printer. Deep machine learning has been applied in the preparation of the jet printer for the realization of the combined footprint. Ceramic and FR4 materials as well as real PCBs were used for the substrates. The obtained results are presented using statistics. They confirm the expectations - use of all solder material in the solder, lack of balls of solder material, non-eutectic melting of the solder material and lack of the tombstone effect. The obtained positive results give grounds for future in-depth study and development of the combined footprint, as well as for its industrialization.