Double Sided PCBs

Double-sided boards (DSBs) have circuits formed on both sides of the boards. They can be categorized into two classes-one without through-hole metallization and one with through-hole metallization, plated-through holes (PTH) Double-sided boards with PTH circuitry on both sides of an insulating FR-4 are connected by moralizing the walls of a hole in the plastic that intersects the circuitry on both sides. This technology, which is the basis for most printed circuits produced.

The single-sided board (SSB) has circuits on only one side of the board and is frequently referred to as the "print-and-etch" the copper during the circuits-forming etching process is usually "printed" on by screen-printing techniques. Its major applications are in packaging consumer electronic products. When the production volume is high. SSBs are manufactured by so-called print-and etch lines.

Multilayer boards have three or more circuit layers; some boards have as many as 60 layers. The most widely practiced method of making multilayer boards is by bonding or laminating, layers of patterned, pre-etched, undrilled copper-clad laminate together. Interconnections between different layers are made through PTHs.  After lamination, the subsequent manufacturing processes for MLBs are more or less the same as those used for DSBs made with the PTH process. Because of the advent of the mass lamination technology, four layer boards, and in some cases, six layer boards can be made with almost the same case as DSBs. Therefore, four layer boards are by far the most popular MLBs. In most MLBs used for mainframe computers.

Flexible PCBs

These are made of polyester and polyimide bases. "Rigi-flex boards," a combination of rigid and flexible boards usually together, are gaining widespread use in electronic packaging. Most rigi-flex boards are three dimensional structures that have flexible parts connecting the rigid boards, which usually support components; this packaging is thus volumetrically efficient.

Membrane Switch Panels