PCB Vapour Barrier Bag Use: Sealing the Board In Buyers and engineers often focus on the finished product and forget the production line behind it. In practice, most field failures can be traced back to process decisions made during assembly. Understanding PCB vapour barrier bag use gives you a practical…

SMT Assembly Process Overview: From Paste to Test A surface mount line is a sequence of machines that each do one thing well, and the quality of the finished assembly is decided by how well the steps agree with each other. Paste, placement and profile are one system rather than…

Power Thick Film Resistor With Thermal Monitoring A resistor that has to absorb a large amount of energy in a short time, or dissipate a continuous power that a chip resistor cannot handle, moves into a different class of package. The element is printed onto a ceramic substrate and housed…

SMD Aluminium Electrolytic Capacitor For Reflow A radial aluminium electrolytic capacitor is one of the last through hole components on many boards. It cannot be placed by a machine that expects a flat body with solderable pads, so it is inserted by hand, clinched, and soldered in a wave. That…

Scanning Acoustic Microscopy for Package Delamination Some of the most damaging defects in a plastic package are invisible from the outside and completely transparent to X-ray. A thin layer of air between the mould compound and the die pad, or between a solder mask and a copper plane, changes almost…

FPC Manufacturing: The Layers Inside a Flex Circuit A flexible circuit looks like a thin printed board, but its construction is a different stack of materials chosen for bending. Understanding the layers explains why a flex design cannot simply be a rigid design printed on a thinner substrate. What a…

Solder Pot Alloy Analysis and Contamination Control A wave solder pot is not a static bath of metal. Every board that passes through it dissolves a little copper, every top-up adds alloy that may be slightly different from what is already there, and every hour at temperature changes the chemistry…

PCB Selective Wave Solder: One Joint at a Time 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…

PCB Baking Before Assembly: Driving the Water Out 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…

FPC Test Clip Connection For Flex Testing Testing a flex circuit during development is awkward in a way that a rigid board is not. The conductors are on a thin, compliant substrate, the pitch at the connector is often 0.2 or 0.3 millimetres, and the gold fingers at the edge…