Step by Step STEP 5: Adhesives, Epoxies and Dispensing

摘要

In addition to the ability to be dispensed stencil printed at high speeds, the liquid SMA must have sufficient wet or green strength to hold a component in position from placement through cure. The cured adhesive must be strong enough to secure the surface mount component to the board during wavesolder operation. After soldering, the adhesive must not affect circuit operation. The adhesive must enable high-speed application of small dots, while delivering consistent dot profile and size. Dot profiles must be high, and the adhesive must be non-stringing. The adhesive should provide high green or wet strength, cure rapidly, be non-slumping during the cure cycle, and provide high strength combined with flexibility and resistance to thermal exposure during the wavesolder process. Finally, good electrical properties are critical.