An accidental discovery by [3DQue] FDM printers can have overhangs that look impossible at first glance. Concentric arcs are key to creating an overhang area. Printing at a cool temperature, with a fan and slow speed is a good idea. The video is also available at [3DQue], there’s also a video from [CNC Kitchen] The technique is described below.
For a quick overview, it might be a good idea to begin with the [CNC Kitchen] Video first. The basic idea is that you build surfaces “in the air” by making small arcs that overlap and get further and further away from the main body of the part. The arcs support each other because they overlap. These results are amazing. There’s a third video below that shows some recent updates to the tool.
We’ve seen a similar technique handcrafted with fullcontrol.xyz, but this is a Python script that semi-automatically generates the necessary arcs that overlap. The surface is a bit odd, but it might be the right solution depending on your reason for printing overhangs. If features are placed on top of the overhang, there may be some warping.
You don’t need any special hardware other than good cooling. Like [CNC Kitchen]This is something we hope mainstream slicers take up. Although it will not be the default setting, it would be an option for parts that could benefit from this technique. The code can be found on GitHub. Perhaps people with experience in mainstream slicers might help make this algorithm more widely accessible and automatic.
What can you create with this tool? If you don’t like arcs, check out conical slicing or non-planar slicing instead.