A fiducial is a solid round copper mark, commonly 1 mm in diameter inside a clear zone two to three times that diameter, free of mask and copper, placed on the board and on panel rails. Pick-and-place machines, printers and inspection systems find two or three of them to correct for board position, rotation and stretch. Local fiducials beside fine-pitch parts give extra accuracy where it counts.
Three fiducials on the rail, not in a symmetric pattern, or the machine will happily load the panel backwards.
Also heard as
- fid
- fiducial mark
- fiducial marker
Related terms
Pick-and-place
Automated machine that picks surface mount parts from reels and trays and sets them on a pasted board.
Panelization
Arranging several boards on one production panel so they are fabricated and assembled together.
Stencil
Thin laser-cut metal sheet used to print solder paste onto board pads before parts are placed.