12 ASSEMBLY OUTLINE & POLARITY MARK

12.1 Assembly Drawing Outlines

The assembly drawing outline should represent the maximum outline of the component body. Unlike the silkscreen outline which has to be created to avoid solder pads (a fake component outline); the assembly outline only gets placed on an assembly drawing that goes to the assembly shop. There is no need to fake this outline.

Assembly outlines can be created with complex drawings to illustrate the actual physical component features or with a simple rectangle. It makes no difference to the assembly shop that has to interpret the assembly drawing. Drawing complex shapes for the assembly outline shows off the PCB designer’s artistic creativity, but once the PC Board goes into production, it makes no difference because the assembly drawing is never used again. The CAD Library of the Future will have 1:1 scale component outlines in the assembly drawing.

Here is some sample assembly drawing component outlines in relationship to the solder pad.

12.2 Assembly Polarity Marking

The assembly Polarity Marking is sometimes totally different than the silkscreen Polarity Marking because the silkscreen must avoid touching the solder pad. Unlike the silkscreen, the assembly drawing can illustrate robust polarity markings to insure that the component is inserted with the correct rotation.

Here is some sample assembly drawing component Polarity Markings in relationship to the solder pad.