Dual Extrusion Support Without PVA

If you have an FDM printer that features multiple hotends or can otherwise switch between different filaments, you’ve surely thought about using the capability to lay down dedicated support material. Historically the filament of choice for this is PVA, since it can be dissolved in water once the print has finished. But if you’ve ever used it, you’ll know it’s not without its own challenges. Luckily, there may be an alternative — [ModBot] had heard that it is possible to use PLA to support PETG and vice-versa so he decided to try it. You can see how it works in the video below.

Of course, you can simply use PLA to support PLA and PETG to support PETG. Depending on the supports and slicer settings, though, it can be hard to remove the support after printing cleanly. Slicers have made major improvements in this area, but it still isn’t ideal. Some use HIPS for support, but that requires a solvent to dissolve and is also a bit exotic compared to PLA and PETG.

To illustrate, [ModBot] printed some test articles with the alternate support and did more reference prints using the same material with different parameters. The typical gap slicers use is 0.2 mm, but when using the different materials you can set the gap to zero. For the reference parts he set the gap to zero and 0.1 mm, both closer than you would normally print.

The PLA-only prints were essentially impossible to separate. While the PETG prints separated with tools, the resulting surfaces were ugly, with support residue and scarring. But the prints with two materials and zero gap pulled apart readily with no tools and left a beautiful surface underneath.

If you have the ability to do dual extrusion, this could be a great trick to have in your toolbox. Granted, PVA will still be of interest if you have support buried deep inside some structure where it is physically difficult to get to. Water can go where tweezers can’t. But for supporting large accessible areas, this looks like a game-changer.

Sometimes automatic supports can use a little help. There are plenty of supports and best practices for supports if you want to fine-tune your process.

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Tree Supports Are Pretty, So Why Not Make Them Part Of The Print?

Here’s an idea that [Nephlonor] shared a couple years ago, but is worth keeping in mind because one never knows when it might come in handy. He 3D printed a marble run track and kept the generated tree supports. As you can see in the image above, the track resembles a roller-coaster and the tree supports function as an automatically-generated scaffolding for the whole thing. Clever!

As mentioned, these results are from a couple of years ago; so this idea should work even better nowadays. Tree supports have come a long way since then, and are available in more slicers than just Cura.

Tree supports without an interface layer is easy mode for “generate me some weird-looking scaffolding”

If you’re going to do this, we suggest reducing or eliminating the support interface and distance, which is the spacing between the supports and the rest of the model. The interface makes supports easier to remove, but if one is intending to leave it attached, it makes more sense to have a solid connection.

And while we’re on the topic of misusing supports, we’d like to leave you with one more trick to keep in mind. [Angus] of Maker’s Muse tucked a great idea into one of his videos: print just the support structure, and use it as a stand for oddly-shaped objects. Just set the object itself to zero walls and zero infill, and the printer will generate (and print) only the support structure. Choose an attractive angle, and presto! A display stand that fits the object like a glove.

You can watch a brief video of the marble run embedded below. Again, tree supports both look better and are available in more slicers nowadays. Have you tried this? If so we’d love to hear about it, so let us know in the comments!

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3D Printing Support Gets Down To Tacks

If you use supports for FDM 3D printing, you might find that some designs are more amenable than others to automatically-generated supports. [Slant 3D] , for example, shows a cool-looking eagle with a downward-curved beak that comes to a point. Using traditional supports would allow the print to succeed, but didn’t allow the beak to form correctly. To combat this, he uses something called a “thumbtack” in the design. There are several flavors, as you can see in the video below, and it widens out the small part yet has a tiny contact with the actual part so you can easily remove it.

One of the thumbtacks looks more like a Hersey’s kiss to us. It makes sense. The point can touch the part to support and the fat base gives a nice target for the automatic support feature in your slicer to grab. There’s also a spherical base so you can rotate to odd angles. The final thumbtack looks like an alien spacecraft and provides multiple contact points.

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