Here is a photo showing some 1/2"-20 threads I printed with my Creality ender 5-S1 in PLA @ 220C… Left is at 0.20mm Layer Height, and Right is at 0.12mm, as printed…
There is absolutely no question which are better!.. I was using a thread file from McMaster Carr for a 2" long threaded rod (with the tapered ends replaced with a countersink), enlarged from 12.7mm OD to 13.0mm, to create the clearance needed for a steel bolt to thread in without having to clean it out with a tap… I was using the “Exclusive” setting in Cura to make sure no filament was extruded past the profile of the part, and printing Inner Walls before Outer (walls only, no Infill), so that the tips of the thread profiles had the best support… A 1/2"-20 steel bolt threads in without a problem, but is slightly tighter in the 0.20mm layer height print…
It doesn’t matter what the Infill settings are, because I specified a wall thickness greater than necessary, so the part is printed with walls ONLY… For that part, which is 20mm OD and about 11.5mm at the smallest diameter of the threads, I used a 2.0mm wall (5 walls per side, times 2 sides = 8 mm)… Cura adds a thicker segment of wall on the “wide” side of the thread, and if it doesn’t, just add one more wall (eg. 2.4mm - 6 walls per side)… Cura will only use the number of 0.4mm thick walls that there is room for in the print… Here is a screen shot of the top view of the print, about halfway down…
If you look closely, the center wall splits into two for the wider side, and then goes back into one for the narrower side (which rotates around for each layer to produce the thread)… Hope that helps…
Yes, that is always a method, and you can print them slightly undersize if you wish… I wanted to see how good a thread you could make with just printing… I’m very pleased!..
