Selective Soldering Hot Tear: Causes and Fillet Control A hot tear is a crack or a lifted edge in a solder fillet that forms as the joint cools, and it is found after selective soldering rather than during it. The joint looked sound when the nozzle left it. The tear…

Liquid Photoimageable Resist: Coating and Imaging Control Liquid photoimageable resist is the light sensitive coating that turns artwork into a copper pattern on an inner layer or a plated pattern on an outer layer. It goes on as a liquid, is dried, is exposed through the artwork and is then…

Wave Solder Pallet Material: Choosing for Heat and Wear Wave solder pallet is the general term for the fixture that carries a board or panel over the solder wave and shields the areas that must not be soldered. The pallet also provides mechanical support, keeps the board flat, and defines…

Component Placement Vision Alignment: Fiducials and Offset Control Vision alignment is the step in which the placement machine locates the board and the component optically before the head releases the part. It is the only closed-loop correction available during component placement, and it determines the placement offset that remains after…

Solder Paste Thawing Control: Time, Temperature and Open Time Paste thawing is the first process step of the print cycle and one of the most frequently skipped. Solder paste is stored cold to slow the chemical reactions that eventually degrade the flux, and it must return to room temperature before…

Press-Fit Hole Tolerance: Diameter, Force and Plating Press-fit is an assembly method in which a compliant pin is pushed into a plated through hole and deforms elastically against the barrel wall, forming a gas-tight connection without any solder. The joint depends on the interference between the pin and the finished…

V-Cut Depth Control: Web Thickness and Blade Wear V-cut is a scoring operation in which a pair of matched blades cuts a shallow groove into both faces of a panel along the line where the boards will later be separated. The cut does not free the board; it leaves a…

AOI Programming: How the Golden Board Sets Inspection Limits An AOI programming workflow usually begins with a physical sample rather than a CAD file, and that sample is the golden board. It is a known-good assembly that captures the process in its nominal condition, and every limit in the inspection…

Infrared Curing: Heat Transfer in a Cure Oven Infrared curing heats a coating by radiating energy onto it, and the coating absorbs that energy and converts it into heat. The mechanism is direct, which makes it fast, and it is also selective, which makes it sensitive to colour, thickness and…

Stencil Coatings: What a Nanocoating Changes at the Aperture A stencil coating is a thin film applied to the walls and surfaces of a stencil so that solder paste releases more completely from the apertures. The most common class is a nanocoating, applied in a controlled process after the stencil…