I sent a board to Elecrow with Fiducials on the layer I ordered a stencil for, I provided the paste layer. The boards and stencil arrived without any fiducial openings in the stencil, I asked about it:
Dear Kevin,
I have checked this problem,the file has no any fiducial.
They are right, my fiducial is a 1mm SMT round pad with a 3mm clearance (IPC 7351 http://www.denatechnologies.com/capabil ... uidelines/ ).
No holes here. Meanwhile JLCPCB used the same project with the same fiducial and produced stencils with 'half-etched' holes, somehow, for some unknown reason I checked the 'half-etched' box, but at least they knew the fiducials needed to be on the stencil.
In the future I'll try creating a layer, call it "讀我 Dú wǒ (READ ME)" and add a simplified exclamation of what a fiducial is for and why a 1mm hole should line up the stencil with the SMT 1mm round pad on the PCB also why where is no 1mm drill hole for the fiducial.
Turns out it is my fault, the Fiducial I have is broken:
The purple 3mm circle is Top Mask, the brown 3mm circle is Keep Out (do I need a Bottom Mask?).
The Fiducial pad 'State' Top/Bottom Paste Mask: was set to No Solder, when the paste layer was generated those pads were left off, no solder, no paste. I understand that the fiducial should be bare copper but with the No Solder settings the four boards I have had manufactured all have the fiducial pad soldered so by setting the 'State' Top/Bottom Paste Mask: to Solder the paste layer now has the 1mm round fiducial, no READ ME needed.