A plated hole connects selected copper layers
A plated through hole extends through the board and has a conductive barrel. It connects only the copper features intentionally joined to that barrel; clearance areas can isolate it from other layers. A non-plated mounting hole has a different purpose and must be identified separately in the manufacturing data.
A through via primarily carries an interlayer connection, while a component hole also receives a lead or terminal. Both need suitable copper geometry, but a component hole has additional fit and assembly requirements. Do not allow a small component hole to be reduced as though it were an adjustable routing via.
Specify the finished opening
The finished plated opening differs from the production drill size because preparation and metallization change its dimensions. State whether the drill table defines finished dimensions, identify plated and non-plated tools, and give explicit tolerances for critical holes. The fabricator determines the production tooling needed to meet that requirement.
Check the maximum lead envelope, including its diagonal for a rectangular lead, against the minimum finished hole. Also assess insertion clearance, solder access and the connector manufacturer’s recommendations. A nominal hole and nominal lead that appear to fit may fail when their tolerances are combined.
Match lead length to the assembly
Board thickness, connector seating height and lead length determine the available protrusion on the solder side. Review these dimensions with the intended wave, selective or manual soldering process. Leads must not interfere with fixtures, neighboring components or the enclosure.
Heavy copper connections can draw heat away from a joint, while insufficient mechanical support can load the barrel. Review thermal connections, annular geometry and connector retention as separate design decisions. A longer lead cannot compensate for an unsuitable hole or a poorly supported connector.
Agree inspection and test evidence
Release the connector drawing, finished hole table, stackup, copper requirements and assembly acceptance criteria together. Specify which critical dimensions need measurement and what evidence is required for hole-wall quality. Electrical testing checks connectivity but does not establish every structural requirement.
For prototypes, verify actual component insertion and soldering before approving volume production. Record any proposed hole-size or pad changes in the revision history. If a connector is press-fit rather than soldered, use its dedicated application specification instead of applying a general soldered-hole allowance.