PCB Sampling in Receiving: Checking a Delivery Fairly 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 explains…

PCB Supplier Corrective Follow Up: Did the Fix Stick 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…

Copper Balance and Panel Distortion Control in Lamination A multilayer board is a stack of materials with different expansion and shrinkage behaviour, pressed together under heat and pressure. If the copper distribution is uneven, the layers move by different amounts and the panel comes out of the press wanting to…

PCB Supplier Performance Data: Keeping Score Electronics manufacturing has become a discipline of small details. Solder paste volumes, placement accuracy, temperature profiles and inspection limits all add up to the final result. This guide looks at PCB supplier performance data from the perspective of a PCBA factory floor, covering scoring…

Capacitive Sensing Electrode Design A capacitive control panel measures the change in capacitance produced by a finger near an electrode. The change is a fraction of a picofarad against a background of several picofarads, so the electrode geometry, the routing and the surrounding ground all matter as much as the…

Solder Wetting And Dewetting Defects Wetting is the process by which molten solder spreads across a metal surface and forms a continuous metallic bond at the interface. It is not simply solder sitting on a pad. A properly wetted joint shows a small contact angle, a smooth concave fillet that…

Color Sensor Interface Circuit Design A color sensor measures the intensity of light in a few wavelength bands and reports the result as numbers. Turning those numbers into a colour that matches what a person sees requires an understanding of the light source, the filtering and the way the readings…

Connector Reliability Under Thermal Cycling A connector is a mechanical assembly made of several materials, and it is mounted to a board that expands at a different rate. The joints at its ends carry the resulting load, and they are the first to fail. Where the Stress Comes From The…

RoHS: Material Compliance Documentation for Assemblies Every product sold into a regulated market carries a documentation obligation. The materials have to be declared, the exemptions recorded and the evidence kept, and none of it is visible on the board. What Has to Be Declared The restricted substance requirements set limits…

Desmear and Hole Wall Preparation Before Copper Plating Drilling a hole through a multilayer board melts a thin layer of resin onto the copper inner layers. That layer is called smear, and it is the enemy of a reliable connection. Left in place, it sits between the copper barrel and…