PCB Design Guidelines

Below are a number of Guideline Rules to follow and keep in mind when designing PCBs. These are general rules that apply for the most PCB fabricators, but it is advisable to check with your fabricator.
Board SizePCB manufacturers have a maximum size board they can handle. Typically this is also their panel size. The PCB fabrication house's panel size is also important when mass producing boards. In this situation one would want to fit as many boards as possible on a panel with as little wasted board space as possible (in order to reduce costs). Normal board spacing for routing (how boards are separated on a panel) is 0.3", plus there is typically a 1.0" to 2.0" border on the board for handling it during processing.Board thickness may also be specified. A standard thickness and type of board is .062" FR4. Other typical board thickness are .010", .020", .031", and .092".
Trace Width and SpacingThe chemical and photographic processes used to produce a PCB put requirements on the minimum width of trace and the minimum spacing between traces. If a trace is made smaller than this minimum width there is some chance it will open (no connection) when manufactured. If two traces are closer together than the minimum spacing there is some chance they will short when manufactured. These parameters are usually specified as "x/y rules", where x is the minimum trace width and y is the minimum trace spacing. For example, "8/10 rules" would indicate 8 mil minimum trace width and 10 mil minimum trace spacing. These rules (especially spacing) apply to any metal on the PCB, including pad to track spacing and line widths for strings on the PCB.Typical modern process rules are 8/8 rules with values as small as 2/2 rules being available. For Press-n-Peel people have had success using 12/12 rules, but values a little larger are easier to make work consistently. However, keep in mind that the board must be soldered and a trace within 8 mils (8/8 rules) of a pad is easier to short than one with greater spacing when hand soldered. For hand soldering 10/10 rules are much easier to solder (if the design density can allow spacing this large).