A 2D Data Matrix code was marked on a sample FR4 circuit board.

2-D codes are widely used in the electronics industry, thanks to their ability to pack a large amount of information into a very small space. Compared to 1-D codes, these codes feature high data density and improved readability. The 0.050" square code, marked on the circuit board in the photo to the left, consists of 10 numeric characters and is readable using a vision system. A 125 mm focusing lens (180 micron spot) directed 18 watts of laser power at a velocity of 15 inches per second (IPS) onto the mark surface, resulting in a cycle time of 1.10 seconds.

FR4, which has the best overall physical, thermal, and electrical properties for circuit board applications, is a flame-retardant general grade laminate created from alkali-free glass cloth coated with epoxy resin and cured under pressure and heat. In addition to providing a good substrate for text and 2D code marking, FR4 can be laser-cut, although edges typically exhibit varying levels of discoloration of charring.