Process Capability for PCB Features: Using CpK What CpK Measures CpK compares the spread of a process with the tolerance it has to meet, and it also takes account of how far the process mean sits from the centre of that tolerance. A process with a small spread but a…

PCB Copper Trace Undercut: The Etch Eats 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 PCB copper trace undercut from the perspective of a PCBA factory floor,…

Stencil Cleaning Cycles and Underside Paste Why the Underside Matters The underside of a stencil is the surface that touches the board, and it is the surface that decides whether the print is clean. Paste accumulates there through aperture fill, through squeeze-out at the aperture edge and through the transfer…

SMT Reflow Solder Joint Pull Test: Pulling the Joint Apart Modern electronics depend on boards that are assembled correctly the first time. Every product – a phone, a charger, a medical instrument or an industrial controller – relies on thousands of solder joints that must conduct current for years. The…

Drill Registration and Its Effect on Pads What Registration Means Registration is the positional agreement between the drilled hole and the copper pattern it has to connect to, measured on each layer. It is not a single number. The hole has to align with the inner-layer pad, with the outer-layer…

Plating Adhesion and Resist Adhesion Problems Two Interfaces Most adhesion problems on a circuit board occur at one of two interfaces: between the copper and the laminate, and between a coating and the copper. The first is created during lamination, when the resin flows against a treated foil and then…

PCB Laminate Glass Transition Measurement: Finding the Softening Point 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 Laminate Glass Transition Measurement, where a small process drift…

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…