Vias and through holes are very similar in that, ultimately, they are both holes that are drilled into your PCB. You could argue that a through hole is just a special case of a via.
But they typically have different purposes and properties and are therefore treated separately in Upverter.
- Vias are plated holes that connect signals and traces from one layer to another. Generally speaking, component pads are not directly connected to via holes (though via-in-pad BGAs are an exception).
- Their geometry can be specified and organized using via classes to make it easy to place many vias of the same kind.
- Vias don't have to be drilled through the entire board (ie. blind and buried).
- Vias can be tented (ie. covered in soldermask), which is especially useful to prevent unintentional solder bridging.
- The shape of the pad is always a circle and can't be changed.
- Can be plated or non-plated. Holes are plated if an electrical or thermal connection is needed between layers. In contrast, holes are typically non-plated to accommodate purely mechanical connections.
- It is almost always intended that a component is directly connected to a through-hole. The connection might be electrical or mechanical (ie. mounting screws).
- Through holes are always drilled through the entire board.
- The pad shape can be changed from a circle to a square, rectangle, etc.