Solder Mask Peeling: 6 Causes and Cures Solder mask peeling is the loss of bond between the coating and the board, and it appears as a lifted edge, a blister or a patch that comes away with a piece of tape. It is found most often after a soldering operation,…

Coating Adhesion: 6 Tests Before Release Coating adhesion is what keeps a conformal coating attached to the board for the life of the product, and it is the property most often taken for granted because a freshly coated board looks identical whether the film is bonded or merely resting on…

Acid Copper Plating: 5 Checks on Chloride Level Acid copper plating relies on a small amount of chloride to work, and the quantity involved is small enough that it is easy to lose control of. Chloride is dosed in tens of parts per million, yet the difference between too little…

Press Pad Care: 5 Rules for Even Lamination A press pad is the compliant layer that sits between the press platen and the caul plate, and it is what turns a rigid machine into an even press. Without it, the smallest difference in stack height would be pressed straight into…

Resin Flow in Lamination: 5 Checks for a Full Fill Resin flow is the movement of resin out of the prepreg and into the spaces of a multilayer stack during the press cycle, and it is what turns a stack of dry sheets into a solid board. Too little flow…

Drill Chart: 5 Checks Before the Drill Runs A drill chart is the document that lists every hole in a design together with its diameter, its plating requirement and the tolerance that applies. It is the bridge between the design file and the drilling machine, and it is also the…

Backup Board: 6 Rules for Drill Entry and Exit A backup board sits under the panel during drilling, and entry material sits on top. Neither ends up in the finished product, and both have more influence on hole quality than their cost suggests. They control where the drill exits, how…

CAM Engineering: 5 Reviews Before Fabrication CAM engineering is the step between a finished design and a shop that can build it. The design file arrives as artwork, drill data and a stackup, and CAM engineering turns that into the films, programs and instructions the line will work from. Everything…

Selective Nozzle: 6 Setup Rules for Mini Waves A selective nozzle is a small pump driven fountain that wets one joint at a time, and it exists because a wave is too coarse for a board that mixes fine surface mount parts with a few connectors. The nozzle produces a…

Outgassing: 6 Checks for Board Materials Outgassing is the release of trapped gas from a material as it is heated or placed under vacuum, and on a circuit board it comes from laminate, solder mask, legend ink, coating and even from the plating chemistry left in a hole. The gas…