track-width

Remedy ¶

Widen the track to the fab’s minimum, or move the board to a process quoted for the width you need. Below the floor a trace will not etch reliably at mainstream yields.

What it means ¶

A routed copper segment is narrower than the board’s declared minimum track width. When the board declares none, the floor is 0.127mm (5mil). That is the minimum trace width of the loosest mainstream fabrication capability, the corpus JLCPCB rule set.

Why engineers want it ¶

Track width is the first constraint every fab publishes and every DRC ships. Below the floor the fab rejects the board or etches it unreliably.

Impact ¶

At best the fab rejects the board at order time. At worst the trace etches into intermittent opens and fails under current.

Scope note ¶

The 0.127mm default is deliberately the loosest published floor, so the rule fires on defects rather than on deliberate tight routing under a capable fab’s own rules. A board that declares its own minimum is held to that instead, because the declaration is the designer saying which process the board is routed for. A KiCad project declares it in board.design_settings.rules, read whichever of the project’s files names the design. An Allegro board declares it through its physical constraint sets, and the board’s minimum is the narrowest width any set allows (agni issue 1432), since Allegro holds each net to its own set. Every finding names which of the two floors it was measured against (agni issue 933). So an HDI board routed at 0.1mm and declaring 0.0969mm is checked against 0.0969mm. netclass-track-width separately checks the width that each of the project’s net classes declares. check.Available gates the rule behind the board-geometry tier, so a netlist-only design reports not-applicable rather than a silent pass.

Query structure ¶

select nets with any segment below the floor.

select N in board.nets where count(S in N.segments where width(S) < floor) >= 1

where floor is the declared minimum track width, else 0.127mm.

Reads: board.copper, board.rules. Tier P.