Work Order and Traveller Control A work order authorises a build, and the traveller that accompanies it records what happened. Between them they answer the questions that arise whenever something goes wrong: which revision was built, which material lots were used, which processes were applied and who verified each step.…

Maintenance Planning for Assembly Equipment Assembly equipment fails in two ways: suddenly, when a part breaks, and gradually, when a parameter drifts far enough to produce defects. Planned maintenance addresses both, and it is justified by the cost of the alternative rather than by a preference for order. An unplanned…

Assembly Floor Layout and Flow How a floor is laid out decides how far a board travels between operations, how much work in progress accumulates beside each station and how quickly a problem at one machine becomes a problem for the whole line. Layout is often treated as a facility…

Protecting Temperature Sensitive Components Not every component can survive the reflow temperature that the solder alloy requires. Electrolytic capacitors dry out, plastic connectors deform, batteries vent, sensors drift and some optical parts lose calibration. The design team usually discovers this after the schematic is fixed, and the manufacturing engineer is…

Backup Material Selection and Drilling Hole Quality Guide Backup material sits underneath the panel in the drilling stack and does several jobs at once: it supports the copper as the drill exits, it dissipates heat, and it helps to clear the chips from the hole. It is a consumable that…

Convection: Design Rules and Process Limits Reflow ovens transfer heat to an assembly in one of two ways: by forcing hot air across it, or by condensing a hot vapour onto it. Forced convection is the default in electronics assembly, and vapour phase is a niche process that survives because…

Prepreg Storage and Handling Rules for Lamination Prepreg is a partially cured material, which means it is chemically active from the moment it is manufactured. It absorbs moisture, its resin advances slowly at room temperature and its flow changes with age, so prepreg storage is a process control that decides…

PCB Warpage Control in Assembly Warpage is the change in a board’s shape when it is heated, and it is one of the few assembly problems that begins in fabrication and ends in the printing and placement equipment. A panel that is flat at room temperature can bow or twist…

Stencil Cleaning and Foil Life A stencil is a consumable that is treated as a tool. It arrives as a precision foil with apertures cut to tolerances measured in microns, and it is expected to deliver the same deposit volume on its ten-thousandth print as on its first. In practice…

Etch Factor and Line Width Control in PCB Production The etch factor is the number that connects the artwork to the finished trace, and understanding it is what allows a shop to hold a line width tolerance on thick copper. When copper is etched it is attacked sideways as well…