Soldering Iron Tip Temperature Verification A soldering station displays a number that is not the temperature of the joint. The sensor sits in the heater or in the tip cartridge, the display is calibrated to that sensor, and the interface between the tip and the work adds its own thermal…

Jet Dispensing for Solder Paste in Small Batch Production Jet dispensing writes solder paste one dot at a time from a nozzle, without a stencil, without a squeegee and without a printing stroke. For small batches, for awkward board shapes and for assemblies where deposits of different heights are needed,…

Electrostatic Discharge Safe Packaging for PCB Shipment An assembled board that leaves the factory in the wrong packaging can arrive electrically damaged without a single mark on it. Electrostatic discharge damage to finished assemblies is usually latent, appearing as leakage or as a marginal input threshold rather than an obvious…

Rework vs Scrap Decision Every assembly line eventually produces a board that does not pass. The question is not whether to rework or to scrap it, but how that decision is made, by whom, and on what evidence. A line that answers those questions in advance saves money on both…

Layer Registration Tolerance Every layer in a multilayer board has to line up with every other layer, and the tolerance that governs the alignment is built up from a chain of steps rather than set at one operation. Registration is therefore a capability that has to be understood from the…

Nitrogen Reflow: Cost, Wetting and Oxide Control in Practice Nitrogen reflow replaces the air in the oven with an atmosphere that is almost free of oxygen, and the change is visible in wetting, in solder ball counts and in the operating cost of the line. Whether it pays depends on…

Selective Soldering: Nozzle Design and Care Selective soldering exists because a wave solder machine is a blunt instrument for a board that mixes surface mount and through-hole parts. The wave treats the whole panel at once, which is fine when everything on the secondary side can take the same thermal…

Reflow Oven Zone Settings: Temperature, Time and Limits Reflow zone settings decide whether a joint forms cleanly or becomes one of the slow, intermittent defects that are hardest to diagnose. The oven is not a single temperature but a series of zones, each doing a different job, and the profile…

Drilling Entry Material and Burr Drilling a printed board is a machining operation, and like any machining operation the result depends on the tool, the material being cut and what is on either side of the workpiece. Entry and backup material sits on the top and bottom of the stack,…

ESD Floor and Wrist Strap Testing An ESD protected area depends on a chain of controls, and a chain is only as strong as the test that proves each link is intact. Floors, wrist straps, footwear, benches and ionisers all have a resistance or a decay time that can be…