Printing In Multi-material? Use These Filament Combos

December 7, 2024 by Donald Papp 15 Comments

If one has a multi-material printer there are more options than simply printing in different colors of the same filament. [Thomas Sanladerer] explores combinations of different filaments in a fantastic article that covers not just which materials make good removable support interfaces, but also which ones stick to each other well enough together to make a multi-material print feasible. He tested an array of PLA, PETG, ASA, ABS, and Flex filaments with each in both top (printed object) and bottom (support) roles.

A zero-clearance support where the object prints directly on the support structure can result in a very clean bottom surface. But only if the support can be removed easily.

People had already discovered that PETG and PLA make pretty good support for each other. [Thomas] expands on this to demonstrate that PLA doesn’t really stick very well to anything but itself, and PETG by contrast sticks really well to just about anything other than PLA.

One mild surprise was that flexible filament conforms very well to PLA, but doesn’t truly stick to it. Flex can be peeled away from PLA without too much trouble, leaving a very nice finish. That means using flex filament as a zero-clearance support interface — that is to say, the layer between the support structure and the PLA print — seems like it has potential.

Flex and PETG by contrast pretty much permanently weld themselves together, which means that making something like a box out of PETG with a little living hinge section out of flex would be doable without adhesives or fasteners. Ditto for giving a PETG object a grippy base. [Thomas] notes that flexible filaments all have different formulations, but broadly speaking they behave similarly enough in terms of what they stick to.

[Thomas] leaves us with some tips that are worth keeping in mind when it comes to supported models. One is that supports can leave tiny bits of material on the model, so try to use same or similar colors for both support and model so there’s no visual blemish. Another tip is that PLA softens slightly in hot water, so if PLA supports are clinging stubbornly to a model printed in a higher-temperature material like PETG or ABS/ASA, use some hot water to make the job a little easier. The PLA will soften first, giving you an edge. Give the video below a watch to see for yourself how the combinations act.

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Swapping Batteries Has Never Looked This Cool

November 29, 2024 by Donald Papp 39 Comments

We don’t know much more than what we see with [Kounotori_DIY]’s battery loader design (video embedded below) but it just looks so cool we had to share. Watch it in action, it’ll explain itself.

Before 3D printers made it onto hobbyist workbenches, prototyping something like this would have been much more work.

[Kounotori_DIY] uses a small plastic linear guide as an interface for an 18650 battery holder and as you can see, it’s pretty slick. A little cylindrical container slides out of the assembly, allowing a spent cell to drop out. Loading a freshly charged cell consists of just popping a new one into the cylinder, then snapping it closed. The electrical connection is made by two springy metal tabs on either end that fit into guides in the cylindrical holder.

It’s just a prototype right now, and [Kounotori_DIY] admits that the assembly is still a bit big and there’s no solid retention — a good bump will pop the battery out — but we think this is onto something. We can’t help but imagine how swapping batteries in such style with a nice solid click would go very nicely on a cyberdeck build.

It’s not every day that someone tries to re-imagine a battery holder, let alone with such style. Any ideas how it could be improved? Have your own ideas about reimagining how batteries are handled? Let us know in the comments!

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Would An Indexing Feature Benefit Your Next Hinge Design?

November 27, 2024 by Donald Papp 2 Comments

[Angus] of Maker’s Muse has a video with a roundup of different 3D-printable hinge designs, and he points out that a great thing about 3D printing objects is that adding printable features to them is essentially free.

These hinges have an indexing feature that allows them to lock into place, no additional parts needed.

A great example of this is his experimental print-in-place butt hinge with indexing feature, which is a hinge that can lock without adding any additional parts. The whole video is worth a watch, but he shows off the experimental design at the 7:47 mark. The hinge can swing normally but when positioned just right, the squared-off pin within slots into a tapered track, locking the part in place.

Inspired by a handheld shopping basket with a lockable handle, [Angus] worked out a design of his own and demonstrates it with a small GoPro tripod whose legs can fold and lock in place. He admits it’s a demonstration of the concept more than a genuinely useful tripod, but it does show what’s possible with some careful design. Being entirely 3D printed in a single piece and requiring no additional hardware is awfully nice.

3D printing is very well-suited to this sort of thing, and it’s worth playing to a printer’s strengths to do for pennies what one would otherwise need dollars to accomplish.

Want some tips on designing things in a way that take full advantage of what a 3D printer can achieve? Check out printing enclosures at an angle with minimal supports, leveraging the living hinge to print complex shapes flat (and fold them up for assembly), or even print a one-piece hinge that can actually withstand a serious load. All of those are full of tips, so keep them in mind the next time you design a part.

Life Found On Ryugu Asteroid Sample, But It Looks Very Familiar

November 27, 2024 by Donald Papp 72 Comments

Samples taken from the space-returned piece of asteroid Ryugu were collected and prepared under strict anti-contamination controls. Inside the cleanest of clean rooms, a tiny particle was collected from the returned sample with sterilized tools in a nitrogen atmosphere and stored in airtight containers before being embedded in an epoxy block for scanning electron microscopy.

It’s hard to imagine what more one could do, but despite all the precautions taken, the samples were rapidly colonized by terrestrial microorganisms. Only the upper few microns of the sample surface, but it happened. That’s what the images above show.

The surface of Ryugu from Rover 1B’s camera. Source: JAXA

Obtaining a sample from asteroid Ryugu was a triumph. Could this organic matter have come from the asteroid itself? In a word, no. Researchers have concluded the microorganisms are almost certainly terrestrial bacteria that contaminated the sample during collection, despite the precautions taken.

You can read the study to get all the details, but it seems that microorganisms — our world’s greatest colonizers — can circumvent contamination controls. No surprise, in a way. Every corner of our world is absolutely awash in microbial life. Opening samples on Earth comes with challenges.

As for off-Earth, robots may be doing the exploration but despite NASA assembling landers in clean room environments we may have already inadvertently exported terrestrial microbes to the Moon, and Mars. The search for life to which we are not related is one of science and humanity’s greatest quests, but it seems life found on a space-returned samples will end up looking awfully familiar until we step up our game.

Your Undocumented Project May Also Baffle People Someday

November 26, 2024 by Donald Papp 49 Comments

What’s life without a little mystery? There’s one less rolling around after historians finally identified a donated mystery machine that had been in storage for years.

Feeding dough through this machine may have been faster, but probably not safer.

The main pieces of the machine are about a century old and any staff who may have known more about the undocumented device were no longer around to ask. The historical society finally posted pictures and asked for any insights, which eventually led to solving the mystery.

The machine is in all likelihood a beaten biscuit maker, which was a type of dense baked good popular in the American south. Making them called for a long and labor-intensive process of pounding and working the dough, and the society says this machine was likely created by a fellow trying to help his aunt streamline her business, offloading the labor of working the dough to a machine.

The machine had no branding of any sort and lacked any identifying marks. Its purpose was doubtlessly obvious at the time, but no records remained and quite possibly none existed in the first place. Sound familiar? Perhaps someday our own undocumented projects and prototypes will mystify people. It’s certainly happened in the case of mysterious Roman dodecahedrons, which remain a head-scratching mystery.

The Junk Machine Prints Corrupted Advertising On Demand

November 26, 2024 by Donald Papp 12 Comments

[ClownVamp]’s art project The Junk Machine is an interactive and eye-catching machine that, on demand, prints out an equally eye-catching and unique yet completely meaningless (one may even say corrupted) AI-generated advertisement for nothing in particular.

The machine is an artistic statement on how powerful software tools that have genuine promise and usefulness to creative types are finding their way into marketer’s hands, and resulting in a deluge of, well, junk. This machine simplifies and magnifies that in a physical way.

We can’t help but think that The Junk Machine is in a way highlighting Sturgeon’s Law (paraphrased as ‘ninety percent of everything is crud’) which happens to be particularly applicable to the current AI landscape. In short, the ease of use of these tools means that crud is also being effortlessly generated at an unprecedented scale, swamping any positive elements.

As for the hardware and software, we’re very interested in what’s inside. Unfortunately there’s no deep technical details, but the broad strokes are that The Junk Machine uses an embedded NVIDIA Jetson loaded up with Stable Diffusion’s SDXL Turbo, an open source AI image generator that can be installed and run locally. When and if a user mashes a large red button, the machine generates a piece of AI junk mail in real time without any need for a network connection of any kind, and prints it from an embedded printer.

Watch it in action in the video embedded below, just under the page break. There are a few more different photos on [ClownVamp]’s X account.

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3D Space Can Be Tiled With Corner-free Shapes

November 23, 2024 by Donald Papp 28 Comments

Tiling a space with a repeated pattern that has no gaps or overlaps (a structure known as a tessellation) is what led mathematician [Gábor Domokos] to ponder a question: how few corners can a shape have and still fully tile a space? In a 2D the answer is two, and a 3D space can be tiled in shapes that have no corners at all, called soft cells.

These shapes can be made in a few different ways, and some are shown here. While they may have sharp edges there are no corners, or points where two or more line segments meet. Shapes capable of tiling a 2D space need a minimum of two corners, but in 3D the rules are different.

A great example of a natural soft cell is found in the chambers of a nautilus shell, but this turned out to be far from obvious. A cross-section of a nautilus shell shows a cell structure with obvious corners, but it turns out that’s just an artifact of looking at a 2D slice. When viewed in full 3D — which the team could do thanks to a micro CT scan available online — there are no visible corners in the structure. Once they knew what to look for, it was clear that soft cells are present in a variety of natural forms in our world.

[Domokos] not only seeks a better mathematical understanding of these shapes that seem common in our natural world but also wonders how they might relate to aperiodicity, or the ability of a shape to tile a space without making a repeating pattern. Penrose Tiles are probably the most common example.