A thermal relief connects a pad or hole to a surrounding plane or pour through a few narrow spokes instead of solid copper. Without it, the plane pulls heat away so fast that the joint never reaches soldering temperature and comes out cold, especially on through-hole parts in wave or hand soldering. Spoke width and count trade solderability against current capacity and thermal performance.
Ground pins on that connector are tied solid into a 2 oz plane, put thermal reliefs on them or nobody can hand solder it.
Also heard as
- thermal
- relief
- wagon wheel
Related terms
Copper pour
Area of copper flooded in by the CAD tool around traces and pads, usually tied to ground or a power net.
Ground plane
Large continuous copper area, usually a whole layer, that serves as ground and as the reference for signals.
Cold joint
Solder joint that never got hot enough to flow and wet properly, leaving a dull, grainy and unreliable bond.