Fan Guards designed for Almond Lee's Printrbot Play shroud: https://www.youmagine.com/designs/printrbot-play-integrated-fan-mounting-frame-plus-diy-fan-guard All the STL's have been run through Netfabb Cloud, so they should be valid. As far as print settings, I suggest minimal layer heights (~50 micron; 0.05556 mm Layer Height in Cura for the Play), 100% infill, and slow printing (30mm/s). Fan Guard Iris_fixed.stl is something of a torture test... Classic grilles are available in ring thicknesses of 0.2 to 0.8mm. Use whatever slices best for you. I find that for a 0.4mm nozzle (included with the Play), Cura slices the 0.6mm variant easily, while the 0.4mm variant requires tweaking of the shell thickness to get a decent slice.I make no guarantees about safety! Use at your own risk!I have not evaluated the airflow characteristics of any of these grilles.Portions remixed from Almond Lee's Printrbot Play Integrated Fan Mounting Frame plus DIY Fan Guard (https://www.youmagine.com/designs/printrbot-play-integrated-fan-mounting-frame-plus-diy-fan-guard) and and Minimalistic 30mm fan grille/guard/cover by seavan (www.thingiverse.com/thing:730594).