Adhesive

Materials used to hold components in place during wave or reflow soldering. This may become a permanent part of the assembly, or  removed after soldering.

Aperture

An opening in the stencil that corresponds to a land area on the circuit to be printed.

Aspect Ratio

A ratio of the thickness of the board to its preplated diameter. A via hole with aspect ratio greater than 3 may be susceptible to cracking.

Blade Attack Angle

The angle formed between the stencil and the squeegee blade during squeegee travel.

Blowhole

A void in a solder connection created by outgassing during the soldering process.

Bond  Liftoff

The failure condition reflected by the separation of a lead from its bonding pad.

Butt Joint

A surface mount device lead that is sheared, so that the end of the lead contacts the board land pattern.(Also called I lead). Butt joint is made by converting the leads of conventional DIP packages to suit surface mounting.