Automation: Design Rules and Process Limits Automation in a board shop is usually justified as labour saving, and that is rarely where most of the benefit comes from. The larger effects are consistency and yield. A machine that performs the same motion every time removes the variation between shifts, and…

Copper Surface Finish Selection For PCBs The surface finish on a printed circuit board is the thin layer between the copper and everything that happens to it afterwards: the storage, the solder, the connector contact, the probe and the coating. It is chosen for the assembly process, but it also…

Labour Productivity in PCB Manufacturing Labour productivity is the output a shop achieves per hour of labour, and it is a useful measure only when the output is defined carefully. Counting panels per hour rewards the shop for making simple boards and penalises it for difficult ones, which is the…

Dielectric Constant Measurement Methods for Laminates The dielectric constant of a laminate determines how fast a signal travels in a trace and how wide the trace has to be to present a given impedance. It is the number a designer uses most often when a controlled impedance stack is designed,…

UV Laser Depaneling For Assemblies Laser depaneling separates boards from their panel with a focused beam instead of a router bit. It applies no mechanical force to the assembly, it can follow any outline including a curve or an internal cut-out, and it leaves no dust in the sense of…

Package On Package Stacking Design A package on package assembly places one packaged device on top of another, with the two joined by a perimeter array of solder balls that carries the signals between them. The arrangement is used where a logic device and a memory device have to be…

Via Tenting: Design Rules and Process Limits Solder mask over a via can be applied in two quite different ways. Tenting covers the via completely, with the mask bridging across the drilled hole and sealing it. Plugging fills the hole with mask ink or with a dedicated plugging material, leaving…

CTE Measurement Methods for PCB Laminate Selection Copper expands about five times as much as the laminate around it, so a plated hole in a printed circuit board is under stress every time the board changes temperature. The coefficient of thermal expansion describes how much a material grows for each…

Solder Thief Pad Design And Paste Control A solder thief is a pad placed next to a joint specifically to take solder away from it. It is not connected to the circuit, or it is connected only to a net where the added solder does no harm, and its purpose…

Digital Manufacturing in PCB Production Digital manufacturing in a board shop means that the data about the work is created once, at the point where the work happens, and is available to everyone who needs it without being re-entered. That definition is deliberately narrower than the phrase suggests, and it…