Selective soldering pallets allow for the soldering of plated through-hole (PTH) components to dual-sided mixed technology assemblies while protecting solder-sider side surface mount devices (SMD). These pallets have machined pockets to clear for components, and to shield thermally sensitive or non-glued parts from the heat and solder.
In some cases, there can be 5 or more different depths of component pockets on the same pallet. The solder apertures are the areas that will expose your PTH leads to solder. These apertures have a wall that presses against the circuit board to control the area that is exposed to the solder. Machined into the fixture is a series of details cut into the bottom surface that is engineered to promote solder flow to all the PTH areas.
While this type of fixture solves many problems, it is very important that the PCB layout follows standard guidelines to allow for adequate space between the PTH and surface mounted devices when selective soldering is being considered.
