Flex Stiffeners: Material and Placement Why a Stiffener Is Needed A flexible circuit is thin and compliant, which is what makes it useful and what makes it difficult to connect. A connector has to be soldered or clamped to the flex, and a thin film will not hold the connector…

Via Plugging Versus Tenting: Which To Use Three Treatments Vias are covered in one of three ways, and the three are often confused. Tenting covers the via with solder mask on one or both sides without filling the barrel. Plugging pushes mask or a dedicated material into the barrel, sealing…

EMI Shielding on PCBs: Cans and Grounding What Shielding Can and Cannot Do A shield can is a metal enclosure soldered or clipped over a circuit to keep electromagnetic energy in or out. It works by reflecting and absorbing fields, and it can only do so if it is connected…

Copper Weight: Choosing the Right Thickness What Copper Weight Means Copper weight is the thickness of the copper foil on a layer, expressed as the weight of one square foot of the foil. One ounce per square foot is about 35 micrometres, half an ounce about 18 micrometres, and two…

PCB Dielectric Loss Measurement: What Matters on the Production Line 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. Understanding PCB dielectric loss measurement gives you a practical…

Building a Drill Table for Fabrication Why a Drill Table Exists The drill table is the summary of every hole in the design, grouped by size and by function, and it is the document the fabricator uses to set up the drilling programme. Without it, the shop derives the hole…

Annular Ring: How Much Is Enough What the Ring Carries The annular ring is the copper that surrounds a drilled hole on each layer where the barrel connects to a pad. It has two jobs: it provides the surface area that the plating bonds to and it carries the current…

SMT Reflow Solder Joint Aging: How the Joint Changes Over Time 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 Reflow Solder…

Thermal Reliefs in Pads and Planes What a Thermal Relief Does A thermal relief is a pad connection that is deliberately narrowed, usually to four spokes, so that a pad connected to a large copper plane does not conduct heat away too quickly. The plane is an excellent heat spreader,…

PCB Solder Mask Surface Energy: A Factory-Floor Review 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. Understanding PCB solder mask surface energy gives you a practical advantage…