Hygroscopic

The ability of a material to absorb and retain moisture from the air.

Hot Zone

The section of a re-flow oven held at maximum temperature. Other zones include per-heat and cooling.

Hole Void

A void in the metallic deposit of a plated through-hole exposing the base material.

Hole Pull Strength

The force necessary to rupture a plated through-hole when loaded or pulled in the direction of the axis of the hole.

Hole Pattern

The arrangement of all holes in a printed board.

Hole Location

The dimensional location of the centre of a hole.

Hole Density

The quantity of holes in a printed circuit board per unit area.

Hole Breakout

A condition in which a hole is not completely surrounded by the land.

Hipot Test

Wherein the assembly or component undergoes a high potential (ac) current.

Heel，Bonding

The part of a lead adjacent to a termination that has been deformed by the edge of the bonding tool.

Heat Sink

Any device that absorbs and draws off heat from a hot object, radiating it into the surrounding atmosphere.

Heat and Pull

A de-soldering method using a device that grasps, heats and pulls the leads to be removed.

HASL

 Hot Air Solder Level (See Solder Leveling)

Haloing Mechanically

Induced fracturing or de-lamination on or below the surface of the base material, it is usually exhibited by a light area around holes, other machined areas, or both.

Halogenated Polyester

A polyester resin modified with halogens to reduce flammability.

Halides

Compounds containing fluorine, chlorine, bromine or iodine, which may be part of the activators in the flux system and must be cleaned.

H.D.I

High Density Interconnect.