Rework and Repair: Limits and Documentation What Rework Covers Rework is the correction of a defect to bring an assembly into conformance, and repair is the restoration of a functional assembly that has failed. In practice the two are treated together, because they use the same tools and carry the…

SMT Stencil Cleaning Interval: How Often the Wipe Buyers and engineers often focus on the finished product and forget the production line behind it. In practice, most field failures can be traced back to process decisions made during assembly. The same discipline applies to SMT Stencil Cleaning Interval, where a…

Insertion Loss Budgets for PCB Channels What Insertion Loss Includes Insertion loss is the reduction in signal power between the transmitter and the receiver, expressed in decibels as a function of frequency. In a board channel it is the sum of several contributions: the dielectric absorption of the laminate, the…

AOI Programming and Escape Prevention What AOI Does An automated optical inspection system photographs the board after reflow and compares what it sees with a reference, using a mixture of image processing and measurements to decide whether each component and joint is acceptable. It finds missing parts, reversed parts, shifted…

PCB Copper Trace Etching Factor: How Sharp the Etch Cuts Electronics manufacturing has become a discipline of small details. Solder paste volumes, placement accuracy, temperature profiles and inspection limits all add up to the final result. This guide looks at PCB copper trace etching factor from the perspective of a…

Laser-Cut Versus Electroformed Stencils How a Stencil Is Made A stencil is a thin metal sheet with apertures through which paste is printed onto the pads. Two processes dominate: laser cutting, in which each aperture is cut from a rolled stainless sheet, and electroforming, in which the sheet is grown…

SMT Reflow Solder Joint Ball Shear: Pushing the Ball Sideways Electronics manufacturing has become a discipline of small details. Solder paste volumes, placement accuracy, temperature profiles and inspection limits all add up to the final result. This guide looks at SMT reflow solder joint ball shear from the perspective of…

Clock Trace Routing: Length and Termination Why a Clock Is Different A clock is a periodic signal that runs at a single frequency, and that changes how it behaves compared with a data line. Its energy is concentrated at the fundamental and its harmonics rather than spread over a band,…

Decoupling Capacitor Placement and Loop Area What Decoupling Does A decoupling capacitor is a local reservoir of charge that supplies a switching device while the power distribution network is still responding. When a logic gate switches, it draws a current pulse in a few hundred picoseconds, and the inductance of…

PCB Surface Finish Solderability Test: Checking the Pad Wets Electronics manufacturing has become a discipline of small details. Solder paste volumes, placement accuracy, temperature profiles and inspection limits all add up to the final result. The same discipline applies to PCB Surface Finish Solderability Test, where a small process drift…