Most of the objects that really bring out the best of what 3D printing has to offer require support material in some way. Some printers can utilize a second dedicated support material like PVA or Ionic to support the main printed part, and wash away with water after the 3D print is finished. Others rely on using the same material for support and the printed object. The techniques in this video should help you create your 3D prints a lot quicker by removing the print time of the support material and post-processing time spent breaking them from your part. Sometimes it’s still unavoidable and you need supports to be able to print your part, and in that case making sure your support settings are optimized is a good idea. We have some other videos on the channel that dive a bit deeper into support setting specifics but lets get right into some of the techniques.

Understanding Overhangs

When designing 3D models that are intended to be 3D printed, it’s important to consider what is the main 3D printing technology being used. FFF 3D printers require gentler overhangs than SLA or SLS, and this still depends on the exact printer used, as some can easily handle a 70° overhang and others can struggle with a 45° overhang. As most users will be working with an FFF 3D printer, aim for 45° overhangs or less to prevent any drooping on printed parts.

For example, let’s say I’m designing a part that needs to be mounted to aluminum extrusion with T-slot channels. For the uninitiated, T-slot allows you to mount hardware after assembly instead of in the middle, which is why a lot of inexpensive printer kits feature them in some way. A small tab can help align the part onto the extrusion, but with a flat bottom this is going to droop. While it won’t be pretty, at least it doesn’t affect the structure of the part enough to warrant a reprint. Instead, add a chamfer to the bottom until the horizontal surface is gone or at least significantly minimized. This also works well for any holes in print, like for bolt holes; instead of making holes perfectly circular, a teardrop shape will print much better unsupported and allow for bolts to be inserted much easier and cleaner.

Printers have a maximum angle for overhangs that they can achieve, with each 3D printer having different capabilities.
Printers have a maximum angle for overhangs that they can achieve, with each 3D printer having different capabilities.

Splitting for Optimum Printing

Depending on the intended use of a finished 3D print, you should aim to make separate parts that are bolted or glued together instead of one piece. Of course, sometimes you can’t avoid printing one part with a lot of support for its complex geometry, but for something like a jig, fixture, or demonstration, model hidden joints and holes sized for screws are a great way to make printing easier.

This E3D Hotend model is something I made in my free time, just as an experiment of following someone’s technical drawings to create a 3D model. This isn’t intended to do any more than show the different parts of an E3D hotend, so gluing different parts together was perfectly fine for this project. The heatsink of an E3D hotend features a series of fins to help dissipate heat. The best way to print this would be vertically to get the best edge on the fins, but as one piece it would take a ridiculous amount of support, be in a lot of hard to reach spaces, and not leave the greatest finish on the underside of the fins. Really, there’s two ways to split and print it without support: straight down the middle vertically, which would have a very obvious seam and some stepping due to the print orientation, or I could split it into over a dozen different rings that slot together and glue to make one clean finished part. I did the latter. You can see that it has a clean finish on all sides, and with the connecting faces hidden within the structure, this method preserves the final look.

Splitting parts into multiple pieces can help remove the need to have support surrounding your 3D print.
Splitting parts into multiple pieces can help remove the need to have support surrounding your 3D print.

Custom Supports

By now, most 3D printing slicers incorporate custom support management, allowing you to add or remove supports from wherever you choose. However, there are still a few that don’t give you much choice other than no support, support touching the buildplate, and support everywhere. For these, I have a technique I don’t employ often, but it can be handy to design and create your own supports within your design software. This has its limitations, as it can be difficult to create supports for complex geometry nearly as well as a slicer can, but the general idea is to design a shape that supports an overhang, select the face that will support your model, and offset it the same distance as your air gap so the support can be easily removed.

Sometimes you don't want support where your slicer generates it, and in that case designing your own is a valuable skill.
Sometimes you don't want support where your slicer generates it, and in that case designing your own is a valuable skill.

No matter the method of 3D printing, there will always be a need to support the complex models we wish to create. I hope these techniques help you clean up your models and optimize their geometry for this particular form of production, in the same way injection molds feature draft angles to allow for clean part removal. There will of course be times when these techniques aren’t enough and you will need to surround your part in support, so make sure you spend some time tuning your support settings before you commit to a 4 day 3D print. Best of luck supporting your creations!

Happy printing!