On The Merits Of A Solid-State Dehumidifier Filament Dry Box

How good are ion membrane dehumidifiers for keeping FDM filament dry and ready for printing? This is the question which [Stefan] at CNC Kitchen sought to answer in a recent video. Like many of us, he was inspired by a video which [Big Clive] made a while ago in which said dehumidifiers were demonstrated for keeping an enclosure free from moisture. Yet would they be able to tackle the much bigger drying job of one or more spools of filament? Thanks to some free samples sent by Rosahl, [Stefan] was able to start answering this question.

Performance of desiccants and dehumidifier element. (Credit CNC Kitchen)
Performance of desiccants and dehumidifier element. (Credit CNC Kitchen)

In the experiments, he used the smaller RS1 (€36.25 a piece) for a single spool container, and the larger MDL-3 (€169) with a Bambu Lab AMS multi-spool unit. Normally such an AMS has three big containers with silica desiccant in it that have to be regularly swapped out, but he modified one AMS to only have the big MDL-3 membrane to dehumidify. A second AMS was left with older silica in its containers, and a third got fresh silica, allowing for some benchmarking between the three units.

The results say a lot, with the initial empty AMS test showing the older silica desiccants topping out quickly and leaving the fresh silica and the membrane dehumidifier to go neck to neck. This is not the usual scenario in which you’d use these dehumidification methods of course, and the small-scale test with the RS1 showed that with a full filament spool in the box, humidity inside the container would only drop very gradually as more and more moisture replaced what was removed from the air. In particular the cardboard element of the spool being used was suspected of being one of the biggest sources of moisture.

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Radioactive 3D Printed Flower Glows And Glows

Glow-in-the-dark projects aren’t that uncommon. You can even get glow-in-the-dark PLA filament. However, those common glowing items require a charge from light, and the glow fades very quickly. [Ogrinz Labs] wasn’t satisfied with that. His “Night Blossom” 3D-printed flower glows using radioactive tritium and will continue to glow for decades.

Tritium vials are available and often show up in watches for nighttime visibility. The glow doesn’t actually come directly from the radioactive tritium (an isotope of hydrogen). Instead, the radioactive particles excite phosphor, which glows in the visible spectrum.

Once you have the vials, it is easy to understand how to finish off the project. The flower contains some long tubes inside each petal. There are also a few tiny vials in the center. The whole assembly goes together with glue.

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3D printed test jig to determine the yield point of a centrally loaded 3D printed beam.

One Object To Print, But So Many Settings!

When working with an FDM 3D printer your first prints are likely trinkets where strength is less relevant than surface quality. Later on when attempting more structural prints, the settings become very important, and quite frankly rather bewildering. A few attempts have been made over the years to determine in quantifiable terms, how these settings affect results and here is another such experiment, this time from Youtuber 3DPrinterAcademy looking specifically at the effect of wall count, infill density and the infill pattern upon the strength of a simple beam when subjected to a midpoint load.

A tray of 3D printing infill patterns available in mainstream slicers
Modern slicers can produce many infill patterns, but the effect on real world results are not obvious

When setting up a print, many people will stick to the same few profiles, with a little variety in wall count and infill density, but generally keep things consistent. This works well, up to a point, and that point is when you want to print something significantly different in size, structure or function. The slicer software is usually very helpful in explaining the effect of tweaking the numbers upon how the print is formed, but not too great at explaining the result of this in real life, since it can’t know your application. As far as the slicer is concerned your object is a shape that will be turned into slices, internal spaces, outlines and support structures. It doesn’t know whether you’re making a keyfob or a bearing holder, and cannot help you get the settings right for each application. Perhaps upcoming AI applications will be trained upon all these experimental results and be fed back into the slicing software, but for now, we’ll just have to go with experience and experiment. Continue reading “One Object To Print, But So Many Settings!”

Multicolor Resin Prints: Give It A Shot

[Thomas TEMPE] has been making two-color resin prints. While printing in multiple colors is old hat for FDM printers, the way resin printers work makes it a more difficult proposition. [Thomas] has a simple solution. First, he prints an item with a cavity where he would like the second color. Then, after printing, he fills the cavity with a different color resin using a syringe and cures it. Simple, really.

Of course, it is all about technique. For fine lines, you’ll want a smaller needle, and you flood the area with the alternate resin and wipe away the excess. For wider lines, you simply fill the cavity from a larger syringe.

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Extreme Waterproof 3D Prints

Since the crew at [CPSdrone] likes to build underwater drones — submarines, in other words — they need to 3D print waterproof hulls. At first, they thought there were several reasons for water entering the hulls, but the real reason was that water tends to soak through the print surface. They’ve worked it all out in the video below.

Since the printer is an FDM printer, it isn’t surprising that the surface has tiny pores; even the tiniest pores will let water in at high pressure. They tried using epoxy to seal the prints, which worked to some degree. They did tests using an example submersible hull that you can try yourself if you like.

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Metal 3D Printing Gets Really Fast (and Really Ugly)

The secret to cranking out a furniture-sized metal frame in minutes is Liquid Metal Printing (LMP), demonstrated by researchers at the Massachusetts Institute of Technology. They’ve demonstrated printing aluminum frames for tables and chairs, which are perfectly solid and able to withstand post-processing like drilling and milling.

The system heats aluminum in a graphite crucible, and the molten metal is gravity-fed through a ceramic nozzle and deposited into a bed of tiny 100-micron glass beads. The beads act as both print bed and support structure, allowing the metal to cool quickly without really affecting the surface. Molten aluminum is a harsh material to work with, so both the ceramic nozzle material and the glass beads to fill the print bed were selected after a lot of testing.

This printing method is fast and scalable, but sacrifices resolution. Ideally, the team would love to make a system capable of melting down recycled aluminum to print parts with. That would really be something new and interesting when it comes to manufacturing.

The look of the printed metal honestly reminds us a little of CandyFab from [Windell Oskay] and [Lenore Edman] at Evil Mad Scientist, which was a 3D printer before hobbyist 3D printers or kits were really a thing. CandyFab worked differently — it used hot air to melt sugar together one layer at a time — but the end result has a similar sort of look to it. Might not be pretty, but hey, looks aren’t everything.

(Update: see it in action in this video, which is also embedded just below. Thanks [CityZen] for sharing in the comments!)

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Tool Changing? Bah! Just Add A Second Gantry

What’s a dual gantry 3D printer? It’s a machine with two completely independent XY motion systems, with two independent hot ends, sharing the same build platform. That might be a little hard to visualize, so head over to [Zruncho 3D]’s Dueling Zero project and get a good look at what what a dual gantry machine looks like.

Dual gantry differs from IDEX, which doubles the amount of moving mass on an axis.

Let’s take a moment to quickly cover the different ways to create multi-filament prints before we dive into what’s different with Dueling Zero. One way to print in multiple filaments (for example, multiple colors) is to swap filaments between a single print head, which is what the Prusa MMU and the Bambu AMS do. However, the main tradeoff is that the filament swapping process can be time-consuming. Another option is IDEX (Independent Dual EXtruder) which has two separate hot ends on the same axis. The main downside there is that an IDEX printer has essentially doubled the moving mass on the axis, which limits speed and can affect print quality. Then there’s toolchanging printers like the Prusa XL, which swap entire heads as needed but have a much higher cost.

The Dueling Zero instead adds a completely independent second gantry, so it has two print heads (like an IDEX) but thanks to the mechanical design it acts much more like a single-extruder 3D printer in terms of print quality and motion control. Speed and acceleration aren’t limited by added mass, either, which is good because slow printers are rapidly falling out of style.

We love how clean and finished the design is. At its core, [Zruncho 3D]’s dual gantry mod (designated D0) is based on the Voron Zero design. Dueling Zero is, to our knowledge, the only open-source and fully documented dual gantry printer out there, which is pretty wild. Watch it in action in the short video, embedded below.

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