With respect to the glue application method for most assemblers it depends on capital costs.  If you already have a dispenser then this may be the best route.  On the other hand, more people are familiar with screen printing and if there is not a lot of dispensing expertise or a dispenser in the assembly area screen printing can be a better alternative.  Once you have a method decided, you then need to choose the material that works the best for the application method and the process throughput.  Although there are materials that can perform double duty (screen printing and dispensing), some are formulated to be high speed dispense, screen printed, or off-contact jetted, in addition some materials are more suited for hard to bond surfaces.  If you would like contact me off line and I can send you some general information on printing vs dispensing and some material guidelines.

With respect to small dots, there are newer materials in development and soon to be released from most SMA suppliers to address small dots. It is true you can have better control of small dot placement and consistency with dispensers over screen printing, for 90+% of people using SMAs they don't get into that territory.  The primary physical characteristic to look into with respect to dot size is the rheology of the material (specifically the Yield Point).  Typically as yield point decreases the dot size decreases in a screen printing process.  The print method (flood versus clean) also plays a role in dot size. One scary thing about small dot sizes I know about is that we have already had people ask us about dispensing dots for 0201 components.  Yikes!  (I wonder if it was going to be a Pb-free process too).


Brian J. Toleno, Ph.D.
Sr. Applications Chemist
Loctite Electronics
15051 East Don Julian Rd
Industry, CA 91746
Ph: 626-968-6511 x304
Cell: 626-215-0879
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