- Absorbtivity :

The property of a material to absorb radiation. E.g. the amount of IR radiation absorbed as a percentage of total exposure

- Accelerated ageing :

exposure of e.g. PCBs to high humidity and raised temperature environment to simulate certain ageing conditions

- Acceptance Test :

Special tests defined and chosen to determine whether a PCB or assembly meets certain requirements

- Acceptable Quality Level :

The maximum number of defects per 100 opportunities, which are accepted as satisfactory average process performance.

- Acid Flux :

A flux based on acid components, mostly utilizing water as a solvent

- Acrylic :

type of glue used in SMT technology

- Acrylic Resin :

A resin that is cured thermally and usually is transparent

- Activation :

Chemical treatment of a metal surface in order to improve the wetting behavior of this surface.Also used to describe the amount of activator [salts, acids] in a flux.

- Activated Rosin Flux :

A flux based on rosin dissolved in alcohol to whichsome organic acid has been added

- Activator :

That part of the flux that enables it to remove oxides from metal surfaces

- Adaptor :

A device that is designed to hold and locate assemblies, which are tested

- Adhesive :

A polymer that is used to join two surfaces, a glue.

- Air knife :

well-defined blast of air. is being used by some after the last wave to remove bridges

- Alcohol :

volatile organic compound. used to help remove ionizable residues or as a solvent in fluxes

- Analog Functional Test :

A series of tests utilizing analog signals that checks boards for certain current output signals.

- Analog In-Circuit Test :

Test procedure to measure component performance prior to power-up

- Annular Ring :

The ring of copper around a drilled or punched hole on a PCB

- Anions :

negative ions

- Angle of Attack :

The angle formed between the front of the squeegee and the surface of the stencil.

- Aperture :

That opening in a stencil that corresponds to some pattern to be printed

- Aqueous Cleaning :

Any cleaning method using water as its main solvent

- Array :

An arrangement of items in rows and colums. A matrix. [e.g. arrays of solder balls on the bottom of a BGA]

- Artwork Generation :

The act of creating the graphic aspects of a circuit pattern for production purposes. Traditionally, this was done by manual drafting. Today most shops use software based programs.

- Assembly :

The production process of mounting parts and components onto a PCB. The soldering or joining process is sometimes considered part of assembly.

- Aspect Ratio :

That ratio, which reflect the board thickness divided by the diameter of the smallest via or through-hole

- ASQC :

American Society for Quality Control

- ATE :

Automatic Test Equipment

- Automatic Component Placement :

In Artwork Generation: The program that determines the actual positioning of components on the PCB. In Production: The use of automatic equipment to place components

- Automatic Test Equipment (ATE) :

Test equipment that performs automatic testing of assemblies

- Automatic Test Generation :

A test program generated by software with or without human programming assistance

- Azeotrop :

A mixture of chemicals that exhibit the same proportion in the liquid and vapor

- µBGA :

Name for certain BGAs that belong to the family of CSP [Chip Scale Packages ]. µBGAs have been developed by Tessera and are, as SLIC at most 20% larger than the packaged chip.