Double Sided Reflow Support and Process Control A double sided assembly is reflowed twice, and the second pass runs with components already attached to the underside. Those components are held only by their solder joints, which are molten again during the second pass, or by an adhesive that has to…

Test Point Placement Rules for In Circuit Test Fixtures Test points are the interface between a finished board and the machine that proves it works. Designers often scatter them at the end of layout, under whatever space is left, and the consequence is a fixture that costs more, probes less…

Carrier Tape and Reel Packaging Standards A component is only useful on a production line if the machine can find it, pick it and place it reliably, and that depends entirely on the packaging. Carrier tape and reels are standardised precisely so that equipment from different makers can handle parts…

PCB Conveyor Standards: Process Details and Inspection Points 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. This article explains…

PCB Conveyor Audit: Process Details and Inspection Points 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. This article explains…

PCB Conveyor Records: Process Details and Inspection Points 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 conveyor records gives you a practical advantage when you…

Fusing Current: Design Rules and Process Limits A copper trace is a fuse that nobody specified. It has a resistance, it heats when current flows, and above some current it will open. Most of the time that behaviour is undesirable, but there are cases where the trace is deliberately relied…

Solder Joint Fatigue Life Estimation A solder joint in a product that cycles between temperatures will eventually fail, and the engineering question is when. Estimating that life is what allows a design to be accepted for a ten year service period without waiting ten years to find out. The methods…

Brittle Fracture in Lead Free Solder Joints A brittle fracture in a solder joint is a separation that happens without the deformation a ductile failure would show. The fracture surface is flat and granular rather than torn, and the failure occurs at a load lower than the joint would normally…

Copper Pour Versus Hatched Pour on Inner Layer Planes Every inner layer needs some copper left behind after etching, and the question is whether that copper should be a solid plane or a grid. The choice affects impedance, thermal behaviour, laminate stress and how easily the board can be built.…