If like me you have the Duet3D Smart Effector and are using a more powerful 30mm hotend fan than the e3d supplied unit for example a Sunon Maglev, you might find due to the compact size of the Smart effector assembly, the fan's coils are inducing a current in the nozzle contact sensor of the effector resulting in erratic performance with the hotend fan on.
The solution is to move the fan outwards by 10mm or so placing it just outside the area containing the strain gauge PCB traces on the effector.
Based on the official E3D V6 fan shroud, this one has a 10mm extension. Drill out the holes to 2.7-2.8mm before screwing in the fan. Fits snuggly on my hotend but I included two holes for a cable tie if you want to use one also.
I have also included radial/blower fan mounts for Sunon 5v 0.68W 30mm blower fans, attach these to the ball stud m3 screws with nuts and bond the fans onto then with superglue.
ABS preferred print as orientated to avoid layer delamination when attaching the shroud.