Trace Resistance: 6 Rules for Reliable Measurement Trace resistance measurement checks the resistance of a conductor, a plated hole or a solder joint by driving a known current through it and reading the voltage that appears across it. It is the electrical method behind continuity testing, coupon evaluation and joint…

SPC Control Charts: 6 Rules for PCB Assembly Lines SPC control charts plot a measured characteristic from a PCB assembly line against time, with a centre line and a pair of limits that come from the process itself rather than from the drawing. When the points wander outside those limits,…

Drill Regrind: Extending Bit Life Without Losing Quality Drill regrind is the process of restoring the cutting geometry of a used carbide bit so that it can be returned to production. Done properly, it extends the life of an expensive tool and keeps hole quality stable; done casually, it produces…

Blowhole Defects in PCB Soldering: 8 Causes and How to Fix Them A blowhole is a small gas pocket that has broken through the surface of a solder joint. It reads as a crater, a pinhole or a frosty blister on the fillet, and it is one of the few…

Reverse Pulse Plating: Better Copper Distribution in Holes Reverse pulse plating alternates a forward plating current with a short reverse pulse, so that copper is deposited and then partly dissolved in a repeating cycle. The purpose is not to plate faster but to plate more evenly, particularly in deep holes…

Glob Top Encapsulation: 6 Rules for COB Dispensing Glob top encapsulation is the process of dispensing a bead of filled resin over a bare die and its wire bonds until the die is buried under a smooth dome of cured material. It protects the most fragile part of a chip…

Panel Border and Routing Margin: How to Size the Frame The panel border is the frame of material that surrounds the working area of a PCB panel, and the routing margin is the allowance between the last board feature and the cut path. Both are usually specified by the fabricator…

Cover Tape Peel Force: 6 Rules for SMT Reels Cover tape peel force is the pull needed to lift the protective film away from a carrier tape pocket, and it sits at the centre of a chain that runs from the tape manufacturer to the placement head. If the force…

Legend Ink Curing: 4 Checks Before the Boards Ship Legend ink curing is the step that turns a printed marking into a permanent one. The ink arrives as a paste or a liquid with a solvent or a photo-initiator system, and it only becomes a hard, bonded print after it…

Eyelet and Turret Terminal Staking on PCB Assemblies: 6 Rules An eyelet is a small metal tube that is pushed through a plated hole and rolled over on the far side so that it is held mechanically as well as electrically. A turret terminal is the same idea with a…