If you’ve ever tried to 3D print, you’ve probably faced the challenge of creating a small hole on top of a larger one.
The typical solution is to add support structures, but in a fascinating video by Angus from Maker’s Muse, he demonstrates an alternative method that can be implemented directly in computer-aided design (CAD) software,
eliminating the need for manual post-processing.
This issue commonly arises when you have a countersink feature for a bolt head or a captured nut on the bottom of the printed part.
Angus begins by showcasing a few other techniques that can be used, such as 3d print the bore over space, incorporating a sacrificial bridge, or angling the overhang at 45 degrees.
While these methods can work, they each have their limitations and trade-offs.
3d print: The sequential overhang
The proposed solution, called “sequential overhangs,” is what Angus introduces next.
The idea involves creating supporting edges within the open space using a step-by-step bridging approach,
which allows the perimeter of the bore to be printed effectively. Initially, two or three bridging layers are added to form a rectangle with the same width as the bore.
Then, another set of bridges is added at a 90-degree angle, transforming the opening into a square shape. For smaller holes, this method should provide sufficient support for initiating the bore perimeter. However, for larger holes, it may be necessary to incorporate three sets of bridges with 60-degree offsets.
While Angus credits Prusa Research,
a well-known 3D printer manufacturer,
for the technique, he acknowledges that he did not invent it himself.
The idea has been previously discussed in a 2014 blog post by nophead, as mentioned in the comments section of the Maker’s Muse video.
Regardless of its origins,
this method proves to be a valuable addition to any 3D printing enthusiast’s design toolbox.
With this innovative approach
, Angus offers a practical solution to the common challenge of printing small holes on top of larger ones.
By incorporating sequential overhangs directly in CAD,
3D printing enthusiasts can enhance their designs and achieve better results without the need for additional manual post-processing steps.