Because components, packaging, and solder connections keep getting smaller, it’s harder to fill the apertures with the required amount of solder ball jet nozzle. Because type 3 solder ball jet nozzle is too large for accurate and repeatable with fine pitch components, demand grows for smaller T4 and T5 solder powders.
T3 solder ball jet nozzle, will fall through a 325 mesh screen but not through a 500 mesh screen, hence the term -325+500.
Spheres categorized as Type 3, or T3, will fall through a 325 mesh screen but not through a 500 mesh screen, hence the term -325+500. This equates to particle sizes of 25 to 45µm; 80% of the particles must meet this size requirement.
Likewise, Type 4 solder ball jet nozzle will fall through a 400 mesh screen but not a 635 mesh screen, equating to particle sizes of 20 to 38µm. There is a lot of size overlap between the T3 and T4 solder powder classes; therefore, T4 solder ball jet nozzle can typically offer a slight edge in fine feature printing without presenting substantial reflow concerns.