Test Program Verification and Defect Escape Control A test program is a piece of software that decides whether a board is good, and like any other software it can be wrong in ways that do not announce themselves. A program that misses a net, applies a limit too generously or…

Etch Uniformity Control Across the PCB Panel Etch uniformity decides whether the traces on a panel finish at the width the design asked for, and it is measured across the panel rather than at a single point. A line that etches the centre correctly and the edges lightly will produce…

Conformal Coating Removal and Rework Practice Coating removal is the least documented operation in most conformal coating processes, and it is the one most likely to damage a board. A finished assembly that needs a component replaced has to have its protective film taken back locally, and the removal step…

Developer pH Control: 5 Checks for Consistent Development Developer pH control is the parameter that keeps resist development repeatable from the first panel of a shift to the last. Alkaline developers lose strength as they dissolve resist, and the change is gradual enough that nobody notices until openings start to…

Lamination Vacuum Hold Time: 5 Settings for Void-Free Pressing Lamination vacuum hold time is the window during which air and volatiles can still leave the stack. Once the resin gels, anything trapped inside stays there as a void. The hold time therefore has to start early enough to remove air…

Exposure Lamp Life Management: 6 Rules for Consistent Imaging Exposure lamp life is managed by hours in most shops and by luck in the rest. Lamps do not fail; they fade. Output falls gradually, the operator compensates with exposure time, and the process drifts away from the window it was…

Press Cooling Under Pressure: 5 Steps for Stable Laminates Press cooling under pressure is the part of the lamination cycle that most shops treat as waiting time. Resin is still mobile while the stack is warm, and the way it cools decides how much the panel shrinks, how evenly it…

Step Tablet Exposure Test: 5 Rules for Reliable Dose Readings A step tablet exposure test converts an invisible lamp condition into a number that can be recorded, compared and acted on. Without it, exposure control depends on how the last panels looked, which is exactly how imaging processes drift quietly…

UV Exposure Energy Control: 5 Checks for Sharp Resist Images UV exposure energy is the dose that converts a photoresist pattern from artwork into a latent image, and it is usually the last variable an operator thinks to question. Exposure looks binary: the panel goes in, the lamps run, the…

Gas Pitting in Electroplated Copper: Causes and Detection A gas pit is a small rounded depression in an electroplated deposit, left where a bubble of gas clung to the surface while the copper was growing around it. The deposit beneath the bubble is thinner or absent, and the pit is…