PCB Manufacturing Tolerances: What a Fabricator Can Hold Every feature on a printed circuit board is produced by a process that has a natural spread, and the tolerance on the drawing is a statement about how much of that spread the design can absorb. Manufacturing tolerances are therefore not a…

Measurement Equipment PCB: References, Guarding and Noise A measurement instrument is judged by numbers, and the board is what makes those numbers mean something. A digital multimeter, a bench power supply or a data logger all rest on a reference and on an analogue front end whose errors have to…

Metal Core PCB: Aluminium Substrates and Thermal Design When a component has to lose several watts through the board beneath it, a glass reinforced epoxy substrate becomes the bottleneck. A metal core board replaces the structural laminate with aluminium or another metal and separates it from the copper circuit by…

Immersion Tin PCB: Flat Finish Cost and Selection Guide Surface finish is one of those decisions that looks minor on a drawing and becomes a production problem six months later. Immersion tin sits between HASL and ENIG in both price and performance, offering a very flat pad for fine-pitch assembly…

Heater PCB Price Guide: FR-4, Aluminum, Ceramic A heater board is a power product with a sensor attached, and that combination drives its cost more than any layout decision. The same circuit that would be trivial on a logic board has to carry several amps, survive a hot enclosure and…

Implantable Medical Device PCB: Manufacturing and Design Guide An implantable device is the most demanding application for a printed circuit board, because it cannot be repaired, it cannot be replaced without surgery, and it operates in an environment that is warm, wet and chemically aggressive. An implantable medical device PCB…

PCB Enclosure Ventilation: From Design to Repeatable Production 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…

Practical Notes on CVD Driver Board Chemical vapour deposition is a process in which a solid material is formed on a substrate from a gas phase reaction inside a vacuum chamber. The equipment that performs it is a collection of demanding subsystems: a vacuum pump, a pressure control valve, a…

PCB Fiducial Placement: Mark Point Design for Assembly A fiducial is a small copper mark that the placement machine uses to find the board. Without it, the machine relies on the panel edges and the tooling holes, and any variation in routing, lamination shrink or conveyor position is transferred directly…

Practical Notes on IQC Quality on a printed circuit board is not created by a final inspection. It is built into the process at three separate gates: incoming material, work in progress and finished product. In the industry these are IQC, IPQC and FQC, and the reason they are separate…