Anode Bag Care: 5 Rules for Copper Plating Baths An anode bag is a porous sleeve that wraps a copper anode in a plating bath, and its job is to hold the anode sludge where it is produced. As the anode dissolves, the insoluble material that was inside the metal…

Core Baking: Preparation, Placement and Process Control Core baking is the drying step that removes absorbed moisture from inner layer cores and, where the process requires it, from prepreg before the stack goes into the press. It is a short operation with an outsized effect, because water trapped inside a…

Iron Contamination: 5 Signs a Solder Bath Needs Alloy Iron contamination is the gradual build up of iron in a molten solder bath, and it comes from the pot itself rather than from the alloy that was delivered. Iron dissolves slowly in molten tin, and once it is in solution…

Permanganate Desmear Control: 6 Steps That Protect the Hole Wall Permanganate desmear is the wet chemical sequence that removes resin smear from a drilled hole so that copper can be plated onto a clean, bondable surface. Smear forms when the drill heats the resin beyond its softening point, and the…

Solder Mask Viscosity: 5 Rules Before Printing Solder mask viscosity is the property that decides how the ink leaves the screen, how it levels on the panel and how much of it stays where it was printed. It is measured in the ink kitchen, it changes with temperature and shear,…

Dip and Look Solderability Testing: 7 Rules Dip and look is a solderability test in which a sample is fluxed, dipped into molten solder and inspected visually. It answers a simple question: does the surface wet, and does the solder cover it evenly. The method does not produce a number,…

Wave Solder Pump Maintenance: 6 Checks That Hold Wave Height The wave solder pump is the component that turns a static bath of molten alloy into a controlled flow of solder across a nozzle. Every joint the machine makes depends on that flow being steady, at the right height and…

Barrel Crack: Preparation, Placement and Process Control A barrel crack is a fracture in the copper plating inside a plated through hole, usually running around the circumference or along the length of the barrel. It appears after thermal cycling rather than at manufacture, which is what makes it a reliability…

Thermocouple Wire: 6 Choices That Change a Profile Thermocouple wire decides what a reflow profile actually measures, and a poor choice turns a good oven into an unknown one. The wire carries the tiny voltage that represents temperature, and anything that distorts that voltage, from the alloy of the conductors…

Solder Mask Application: 5 Methods Compared Solder mask application is the step that covers the copper that must not be soldered, and the method chosen decides the thickness that ends up over a trace, in a via and along an edge. Screen printing, curtain coating and spray coating are the…