Laser Drilling Control: 5 Parameters for Clean Microvias Laser drilling control forms the microvias that carry current between the outer layers of an HDI board, and the process window is narrow. A via that is slightly undersized or slightly tapered will still plate, but it will fail later under thermal…

Peel Test: 5 Rules for Repeatable Plating Adhesion Results A peel test is the oldest and simplest measure of plating adhesion, and it is also the one most often performed inconsistently. A strip of plated copper is pulled away from the laminate and the force is recorded, but the number…

Selective Soldering Nozzle Alignment and Maintenance Selective soldering applies molten solder to one joint at a time through a small nozzle, and it exists because a wave soldering step is unsuitable for a board that already carries surface mount parts on the same side. The nozzle is what makes the…

Level Sensor Control: 5 Checks for Reliable Tank Levels Level sensor control rarely attracts attention until a tank overflows or runs dry, and by then the cost is already paid. The sensor is the only instrument that knows how much solution is in a tank, and everything downstream depends on…

Vacuum Pump Maintenance: 5 Checks for Etch and Plasma Lines Vacuum pump maintenance is invisible until a plasma or etch tool stops in the middle of a lot. The pump is the only machine on the line that runs continuously and wears with every hour, and its condition shows up…

PCB Cascade Rinse: Flow Rate and Drag-Out Control A cascade rinse uses a series of tanks where clean water enters at the last tank and flows backwards towards the first. Each stage dilutes what the previous one carried out of the process tank. The arrangement reaches a much higher level…

UV Curing Control: 5 Rules for a Fully Cured Coating UV curing control decides whether a printed coating is fully reacted or only dry to the touch. A UV cured ink or mask looks finished the moment it leaves the lamp, and the difference between a full cure and a…

Flex Coverlay Bonding: Lamination Without Trapped Air A coverlay is the flexible equivalent of a solder mask, and it is bonded to the finished circuit as a separate layer rather than printed as a coating. It carries an adhesive on one side, and the lamination cycle has to flow that…

Placement Nozzle Wear: Vacuum, Alignment and Pick Reliability The placement nozzle is the last element in the machine that touches a component, and its condition decides whether the part is picked, held through the move and released in the right place. A nozzle that leaks vacuum or has a worn…

Stencil Foil Damage: Dents, Creases and Aperture Control Stencil foil damage is any physical change to the foil that alters how paste leaves the aperture. Dents, creases, scratches and deformed apertures all fall into the same family, and all of them print differently from a new foil. The damage is…