Metal Core and Aluminium PCBs What a Metal Core Board Is A metal core board replaces the usual laminate with a metal base, usually aluminium, covered by a thin dielectric layer and the copper circuit. The metal base provides a thermal path that a normal laminate cannot, because the dielectric…

Rigid-Flex Design and Transition Zones What Rigid-Flex Solves A rigid-flex board combines rigid sections that carry the components with flexible sections that carry the connections, so that the assembly can fold into a shape that a rigid board cannot. It removes connectors and cables, which improves reliability and saves space,…

PCB Via Reliability Testing: Putting the Hole Under Stress Modern electronics depend on boards that are assembled correctly the first time. Every product – a phone, a charger, a medical instrument or an industrial controller – relies on thousands of solder joints that must conduct current for years. This article…

Solder Mask Colour and Material Selection More Than a Colour Solder mask is usually discussed as a colour, and the colour is the least important of its properties. The mask is a polymer that has to adhere to the laminate and the copper, survive the fabrication processes and the soldering…

Copper Plating Thickness in Vias What the Plating Has to Do The copper plating in a via is both the electrical connection between the layers and the mechanical structure of the barrel. It has to carry the current, it has to withstand the expansion of the laminate during soldering and…

Drilling Quality and Hole Wall Condition Why the Hole Begins the Via A plated hole is only as good as the hole it was plated into. The drilling operation cuts through the copper, the laminate and the glass fibres, and it generates heat that the laminate and the resin must…

SMT Reflow Solder Paste Bead Size: The Grain in the Powder Modern electronics depend on boards that are assembled correctly the first time. Every product – a phone, a charger, a medical instrument or an industrial controller – relies on thousands of solder joints that must conduct current for years.…

Panel Utilisation and Board Nesting Why the Panel Matters A board is not fabricated on its own. It is placed on a standard panel along with other boards or with several copies of itself, and the panel is what goes through the drilling, plating, imaging and etching steps. The number…

Surface Finishes: ENIG, OSP, HASL and Silver Why a Finish Is Needed Copper oxidises, and an oxidised pad does not wet. The surface finish is the thin layer that protects the copper between fabrication and soldering and that allows the solder to form a joint. Every finish is a compromise…

PCB Copper Trace Connector Launch: Where the Trace Meets the Plug Modern electronics depend on boards that are assembled correctly the first time. Every product – a phone, a charger, a medical instrument or an industrial controller – relies on thousands of solder joints that must conduct current for years.…