Custom FDM printing thread profiles for fusion 360

3D printing common 60° V thread profiles can be a frustrating experience. To generate an accurate profile thread needs to be printed in the vertical position, but this leads to overhangs of 60°, and that can be problematic to print. How problematic it is depends on a few factors, the filament in use, the print speed, and how much cooling is employed. The most common ways of guaranteeing a good print, are increasing cooling, or decreasing print speed. Increasing cooling can cause bad layer adhesion if taken to far, and slowing down the print speed can drastically increase print time.

A lot of people work around the issue by using custom thread profiles. Depending on what cad software you use, this can be easy or a very daunting task. I’m a Fusion 360 user, and I find it to be a fairly tedious task. To try and avoid manually creating a thread every time I want to print one, I decided to do some research a few weeks ago, and see if custom profiles can be loaded into Fusion 360. I found this Autodesk support article that explain how to load custom profiles. It’s kind of a hack, but it works well.

Given that custom profiles are possible I sat down and wrote a simple PHP script that generates the needed xml files for fusion. To ensure that the profiles are strong as well as easy to print, I chose a trapezoidal profile. The script generates 5 profiles with thread angles ranging from 50° to 90° (65° to 45° overhangs). The profiles also use a simpler and more generous tolerance system. The Fusion 360 xml files as well as the php script to generate them can be downloaded from the GitHub repository. If you are so inclined, you can easily update the script or json configuration file to generate completely custom thread profiles.