Test Fixture Maintenance and Probe Replacement A test fixture is a precision assembly that is used until it fails, and its failure looks like a product failure. A probe that has worn, a fixture that has been dropped or a spring that has lost its force produces readings that send…

Thermal Cycling Qualification For Boards A board in service sees the temperature change every time the equipment is switched on and every time the load changes. Each change makes the materials expand by different amounts, and the difference is carried by the joints, the vias and the interfaces between the…

Flux Residue and Board Cleanliness Requirements in Assembly Every soldering operation leaves something behind. Flux is essential for wetting, but the residue it leaves on the board is a chemical film with its own electrical behaviour, and whether that film is harmless or damaging depends on its chemistry, its quantity…

Flying Probe and Fixture Test Cost Comparison for New Builds Electrical test is the last gate before a board leaves the shop, and the method used to open it has a cost structure that changes completely with volume. A flying probe needs no tooling and is ready as soon as…

Blind and Buried Vias: Density Without Dead Layers Blind and buried vias exist because a through hole occupies every layer it crosses. On a dense board the through holes themselves become the limiting factor: they block routing channels on inner layers, they force the escape pattern of every large device,…

High Precision PCB Batch Prototyping and Stackup Control A high precision pcb run is decided long before the first panel enters the line. Batch prototyping means several panels are produced from one set of data, so any weakness in the preparation is repeated across the whole lot instead of appearing…

ARM Industrial Control Board Design for Fanless Systems An industrial controller that runs for years inside a cabinet has different priorities from a desktop computer. An arm industrial control board is built around those priorities: modest power, no moving parts and interfaces that survive being wired to a machine. What…

ESD Control for SMT Lines and Component Handling Practice A discharge you cannot feel can destroy a component you cannot see damaged. Static voltages of a few hundred volts are imperceptible to a person and entirely capable of punching through the thin gate oxide of a modern device. Because the…

Four Layer PCB Design Process From Schematic to Gerber A four layer board is the first stackup that gives a designer dedicated power and ground planes, and that changes the way the job is planned. The four layer pcb design process is not a longer version of a two layer…

The Role of the PCB in the Electronics Production Process A consumer electronic product is usually judged by its case, but the schedule is normally set by the board inside it. In the electronics production process the printed circuit board is the item that connects the industrial design, the firmware…