Add Fiducial Mark and Tooling Strip To Your PCB Design
If there is no problem with your PCB design, prototyping test, and the assembly process, probably most of us may think that the everything is under control. I might agree with you before, however, this exact confidence of mass producing this PCB caused me thousands of dollars when my PCB assembly supplier highlighted that the PCBs are missing fiducial marks and tooling strips. Both are necessary to facilitate the assembly process. Therefore, I want to talk something about PCB fiducial mark and tooling strip.
PCB Fiducial Marks
Fiducial mark is a feature or a target printed on the copper layer of the PCB design. Pickup and placement assembly machine can accurate positioning surface mount components on the PCB with the help of fiducial marks.
Though not every design require a local fiducial, global fiducial is almost necessary for most assembly machines when using surface mount components in your design.
PCB Tooling Strip
One of the most common mistakes easily ignored by new designers is PCB tooling strip. Although it has nothing to do with complex circuitry that made your design works, it is simply an extension of the PCB to be held in place by the machine as the components are being populated.
PCB tooling strip is manufactured as a breakout section of the actual design and can be easily removed after PCB assembly. If the actual space of PCB board is tight, you can place the global fiducial mark on the tooling strip.
The following is recommended as it works well with most PCB assembler:
each fiducial mark is 1 mm in diameter;
3 of fiducial marks are 5 mm from the edge;
1fiducial mark is 10 mm from the edge;
the tooling strip is 6 mm wide.
Finally, what I want to emphasize is that adding fiducial mark and tooling strip is no rocket science, but ignoring this part in your PCB design may cause you more time and cost.