Tape Splice Control: 6 Rules for SMT Reels A tape splice is the joint that lets a running placement machine move from an empty reel to a full one without stopping the line. Done well, the joint passes through the feeder like any other length of tape. Done badly, it…

Nozzle Vacuum: 5 Checks That Stop Lost Components Nozzle vacuum is the pressure difference that holds a component on the tip of the placement head between the feeder and the board. It is produced by a venturi or a pump, measured by a sensor in the head, and it has…

Plating Rack Maintenance: 5 Checks Before a Run A plating rack is the electrical and mechanical interface between the rectifier and the panel, and most plating defects that are blamed on chemistry start here instead. The rack carries current to every panel through contact tips, holds the work at a…

Layer Registration: 7 Controls Before Lamination Layer registration is the alignment of every patterned layer to a common reference, and it decides whether a plated hole lands inside its pad on all of them. The tolerance is small: on a dense board a shift of 75 microns between inner layers…

Plating Bath Analysis: 6 Checks for Copper Plating Plating bath analysis is the routine that decides whether a copper plating tank can be trusted with the next lot. Two tools carry most of the weight: titration, which measures the concentration of the main constituents, and the Hull cell, which produces…

Stencil Tension: 6 Frame Checks Before a Print Run Stencil tension is the load held in the mesh that stretches a laser cut foil across its frame. It is set when the stencil is mounted, it falls slowly through the life of the tool, and it decides how evenly the…

Preheat Ramp Rate: 6 Rules for Reflow Profiles The preheat ramp is the first climb a board sees inside the reflow oven, and it sets the condition of the paste before any melting begins. Too steep and the flux volatiles escape as spatter, lifting paste off the pads; too gentle…

DI Water Resistivity: 5 Rinse Control Rules DI water resistivity is the number that tells a wet process line whether its rinsing is actually working. Deionised water conducts almost nothing, so any fall in resistivity is caused by ions that came off the panel or out of the previous tank,…

Tin Stripping After Plating: 5 Process Checks Tin stripping is the step that removes the tin resist after the copper has been etched, and it decides the quality of the copper surface that the solder mask will later cover. In a solder mask over bare copper flow the plated tin…

Nano Coated Stencil: 6 Rules for Paste Release A nano coated stencil carries a thin surface layer on the aperture walls and on the foil face that lowers friction between paste and metal. The layer is measured in hundreds of nanometres, so it does not change aperture size or foil…