Gerber Data Format

Gerbers are a version of G-CODE Data Format commonly used in the manufacture of PCBs.

From a sample file, we can see the definition of a series of "apatures" with the %ADD command, followed by a number (must be 10 or higher) then a shape letter, comma, size, etc... The shapes are:

R Rectangle
C Circle
O Oblong

%ADD15R,0.080X0.013*%
%ADD16C,0.013*%
%ADD17C,0.015*%
%ADD18C,0.008*%
%ADD19C,0.010*%
%ADD20C,0.005*%
%ADD21O,0.075X0.065*%

Later in the file, the D15 command references the first line shown above, %ADD15R,0.080X0.013*% where a rectangle 0.08 by 0.013 inches is defined. It then move the location to 10.402, 8.651 using the X and Y letters and the D02 (move cursor) command. On the next line, the D03 command exposes the D15 appature at that location.

D15*
X10402Y8651D02*
D03*

Appatures can also be used to draw lines. Here, the D16 appature is used at a starting point set with the D02 command, but then it is "stroked" to the next point via the D01 command.

D16*
X10464Y8680D02*
X10509Y8726D01*
X10464Y8645D02*
Y8680D01*