The Department of Electrical Engineering at IIT Kanpur has a variety of devices and machines to produce single layer, double layer plated through printed circuit boards (PCBs), multi layer (max 8 layers) plated‐ through PCBs, for through pin and surface mounted devices Printed circuit boards are electronic circuits boards created for mounting electronic components on a nonconductive board, and for creating conductive connections between them. The creation of circuit patterns is accomplished using both additive and subtractive methods. The conductive circuit is generally copper, although aluminum, nickel, chrome, and other metals are sometimes used. There are three basic varieties of printed circuit boards: single‐sided, double‐sided, and multi‐ layered. 1. Single sided PCB: conductors on only one surface of a dielectric base. 2. Double sided PCB: conductors on both sides of a dielectric base, usually the two layers are interconnected by plated‐through‐holes (PTHs). 3. Multi‐layer: conductors on 3 or more layers separated by dielectric material and the layers are interconnected by PTH or pads 4 layer PCB is a sandwich of 2 double layered PCBs. Likewise 6 layer PCB is a sandwich of 3 double layered PCB. This sandwiching is done by placing oxidizing material between double layered PCBs The spatial and density requirement, and the circuitry complexity determine the type of board to be produced. Process steps invo olved in PCB B fabrication are shown in the following if you want to learn more about PCB Manufacturer China PCB manufacturing services www.projectpcb.info do a great job, click here to visit their web site right now.