Dispensing
By Gary Helmers
VP Creative Automation

How can current dispensing technology help with the conversion to lead-free?

Lead-free pastes require new flux systems. Some of the new flux systems are less "sticky". The paste would rather stay on the needle than transfer to the substrate. Previous generation solder dispensers (auger pumps and other time-pressure devices) extrude material to the end of the needle and then dab it off onto the substrate. The latest dispensing technologies drive the solder paste down the needle tube with sufficient velocity to cause the paste to "positively wet" to the substrate. This helps to address a wider variety of flux systems. By eliminating one more potential problem area, current dispensing technology provides a wider process window and better chance of success with lead-free paste. The most capable pump for lead-free paste is the Piston Positive Displacement Pump, providing volumetric accuracy and positive wetting.