Soldering SMD components

SMT (Surface Mount Technology) dominates electronics manufacturing today. Most modern devices use surface-mounted components.

What are SMD components?

Components soldered directly onto the board surface, without wire leads through holes – much smaller than THT.

A good soldering station with a fine tip, tweezers, flux, desoldering braid and ideally hot air. Browse the range under soldering equipment.

With small components, flux is crucial – it improves wetting and prevents bridges.

For resistors and capacitors, first tin one pad, place the component and solder the other side.

Fix the leads at the corners, then solder each lead or use drag soldering.

With no visible leads – best done with hot air or by pre-tinning the pads.

Drag a knife or hoof tip with plenty of flux along the row of leads.

Usually 300–350 °C, higher for lead-free – see lead-free soldering.

Bridges, cold joints and too little flux. More in the most common soldering mistakes.

Inspect for bridges, wetting and cracks with a magnifier or microscope.

Faulty SMD components are removed with hot air – see SMD component repair.

SMD soldering requires fine tips, flux and patience. Find more guides in the ESD Guide.