Gold Embrittlement in Solder Joints: Thickness Limits and Control Gold is a finish that protects a surface before assembly and then becomes a liability during it. Dissolved into molten alloy it forms hard intermetallic plates that sit exactly where the joint carries its highest strain, and the resulting failure appears…

Dimensional Verification of Assembled Boards An assembled board has dimensions, and they matter as soon as it has to fit into an enclosure, sit on a mating connector, or pass a camera module through a hole. Dimensional verification on an assembly is different from dimensional inspection of a bare board,…

High-Mix Scheduling and Changeover Discipline In a high-mix shop the machines rarely run long enough for their rated speed to matter. What matters is how often they stop and how long they take to start again. A line that changes over six times a shift spends a large part of…

Mixed-Technology Assembly: Process Sequence and Control A mixed-technology assembly carries surface mount parts and through-hole parts on the same board, and the sequence in which they are attached is a design decision rather than a matter of shop preference. The sequence determines how many thermal excursions the assembly sees, which…

Incoming Inspection: PCB Incoming Laminate Inspection Before Fabrication Laminate arrives with a certificate and a part number, and neither proves that the material in the box matches what the stack was designed around. Incoming inspection exists to close that gap, because a laminate with a lower glass transition temperature or…

PCB ESD Control Standards: Agreeing the Rules 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 ESD control standards from the perspective of a PCBA factory floor, covering…

PCB ESD Control Defects: What Goes Wrong 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 ESD control defects from the perspective of a PCBA factory floor, covering…

PCB ESD Control Records: Writing It Down 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 ESD control records from the perspective of a PCBA factory floor, covering…

Zone Temperature: Design Rules and Process Limits A reflow oven’s zone temperature is the air temperature the controller holds in that zone, measured by a thermocouple mounted somewhere inside it. It is not the board temperature, and on a cold start or a light load it is not even a…

Rework Heating Profiles for Fine Pitch Assembly Repairs Rework removes the protection that a controlled reflow profile provides and replaces it with a hand held tool, a judgement about when the joint is ready and a thermal history that nobody records. On fine pitch assemblies, that difference decides whether the…