This $0 Filament Drybox Needs Nearly No Parts

November 9, 2021 by Donald Papp 20 Comments

All 3D printer filament benefits from being kept as dry as possible, but some are more sensitive to humidity than others. The best solution is a drybox; a sealed filament container, usually with some desiccant inside. But in a pinch, [Spacefan]’s quick and dirty $0 drybox solution is at least inspiring in terms of simplicity.

The only added part is this 3D-printed fitting.

[Spacefan]’s solution uses a filament roll’s own packing materials and a single 3D-printed part to create a sealed environment for a single roll. The roll lives inside a plastic bag (potentially the same one it was sealed in) and filament exits through a small hole and 3D-printed fitting that also uses a bit of spare PTFE tubing. The box doubles as a convenient container for it all. It doesn’t have as much to offer as this other DIY drybox solution, but sure is simple.

While we appreciate the idea, this design is sure to put a lot of friction on the spool itself. It will be a lot of extra work to pull filament off the spool, which needs to turn inside a bag, inside a box, and that extra work will be done by the 3D printer’s extruder, a part that should ideally be working as little as possible. The re-use of materials is a great idea, but it does look to us like the idea could use some improvement.

What do you think? Useful in a pinch, or needs changes? Would adding a spindle to support the spool help? Let us know what you think in the comments.

Simplify 3D Printer Wiring With CAN Bus

November 3, 2021 by Dave Rowntree 56 Comments

[mark] had an interesting idea when looking at all the wiring of a typical 3D printer; Use CAN Bus. There are a lot of wires going to the extruder assembly, and with most designs this thing is flying around at quite some speed. You’ve got connections for powering the heater, fan power, four wires for the extruder motor, thermistor sensor wires. You get the idea. Lots of wires. Worse, they’re all moving around with the axis, and if failures occur at either end due to poor strain relief, or the conductors themselves break, then all manner of interesting failures can occur. If the hot end thermistor connection goes open circuit, usually no damage occurs but the temperature control goes out the window and your print will fail.

Now if you push the electronics needed to drive and control the extruder, directly onto the moving body itself, and hook-up to the main printer electronics with CAN Bus, you can do the whole moving interconnect thing with a measly four wires. Yes, you need another PCB assembly, so it adds cost, but it does also simply the electronics at the control end, so some savings can be made. [mark] has used CAN Bus due its availability with modern microcontrollers and also its designed-in robustness, thanks to its automotive and industrial heritage. When you think about it, this is a rather obvious thing to do, and we’re not sure why we’ve not see it much before.

If you want to dig into the detail, the project GitHub has the schematics and code ready to go.

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3D Printed Printing Plates Made Using Modern Tools

October 27, 2021 by Dave Rowntree 15 Comments

It’s widely accepted that the invention of the printing press by Gutenberg in the 15^th Century was the event that essentially enabled the development of the modern world, allowing access to knowledge beyond anything that came before, even if the Chinese got in on the bookmaking act some 500 years previously. Fast-forward a few centuries more and we’ve got the ability to design electronics from our arm chairs, we can print 3D objects from a machine on the coffee table, and 3D modeling can be done by your kids on a tablet computer. What a time to be alive! So we think it’s perfectly fine that [Kris Slyka] has gone full circle and used all these tools to make printing plates for a small press, in order to produce cards for her Etsy business.

Now before you scoff, yes she admits quite quickly that KiCAD wasn’t the best choice for designing the images to print, since she needed to do a lot of post-processing in Inkscape, she could have just dropped the first step and started in Inkscape anyway. You live and learn. Once the desired image was fully vectorised, it was popped into OpenSCAD in order to extrude it into 3D, thickening the contact to the base to improve the strength a little.

[Kris] demonstrates using the registration marks to align the front and rear side plates, and even (mostly) manages adding a second colour infill for a bit more pizzazz. The results look a little bit wonky and imperfect, exactly what you want for something supposed to be handmade. We think it’s a nice result, even if designing it in KiCAD was a bit bonkers.

For those interested in the OpenSCAD code, have a butchers at this gist. This project is not the first 3D-printed printing press we’ve covered, checkout the Hi-Bred for an example, and here’s the Open Press Project if you’re still interested.

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Line of electromechanical water valves dispensing a pattern of water droplets

Gravity-Defying Water Drop Display Shows Potential

October 23, 2021 by Dave Rowntree 9 Comments

[3DPrintedLife aka Andrew DeGonge] saw that advert for gatorade that shows some slick stop-motion animation using a so-called ‘liquid printer’ and wondered how they built the machine and got it to work so well. The answer, it would seem, involves a lot of hard work and experimentation.

Conceptually it’s not hard to grasp. A water reservoir sits at the top, which gravity-feeds into a a series of electromechanical valves below, which feed into nozzles. From there, the timing of the valve and water pressure dictate the droplet size. The droplets fall under the influence of gravity, to be collected at the bottom. From that point it’s a ‘simple’ matter of timing droplets with respect to a lighting strobe or camera shutter and hey-presto! instant animation.

As will become evident from the video, it’s just not as easy as that. After an initial wobble when [Andrew] realised that cheap “air-only” solenoids actually are for air-only when they rusted up, he took a slight detour to design and 3D print his own valve body. Using a resin printer to produce fine detailed prints, enabled the production of small internal passages including an ‘air spring’ which is just a small chamber of air. After a lot of testing, proved to be a step in the right direction. Whether this could have been achieved with an FDM printer, is open to speculation, but we suspect the superior fine detail capabilities of modern resin printers are a big help here.

In a nice twist, [Andrew] ripped open and dissolved a fluorescent marker pen, and used that in place of plain water, so when illuminated with suitably triggered UV LED strips, discernable animation was achieved, with an eerie green glow which we think looks pretty neat. All he needs to do now is upgrade the hardware to make a 3D array with more resolution, and he can start approaching the capability of the thing that inspired him. Work on some custom electronics to drive it has started, so this is one to watch in the coming months!

We’ve seen many water-based display device before, like this one that projects directly onto a thin stream of water, and this strangely satisfying hack using paraffin and water, but a full 3D Open Source display device seems elusive so far.

All project details can be found on the associated GitHub.

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Testing 3D Printed Cutting Blades Is Scary Work

October 22, 2021 by Lewin Day 15 Comments

[Ivan Miranda] comes from a land where the shops close on Sundays. Thus, when he found himself in need of a cutting blade, he realised he would have to build his own, or simply wait. He elected to do the former, and we get to enjoy the journey. (Video, embedded below.)

His first attempt was to cut a wooden plank with a 3D-printed cutting blade fitted to a mitre saw. After setting up the mitre saw to cut while he was at a safe distance, [Ivan] elected to test the blade. Alas, it simply melted, and the wood was barely scratched, so [Ivan] went back to the drawing board.

His second attempt was to CNC mill an aluminium blade, which was a full 6 mm thick. The saw needed some modifications to the saw to fit properly, but it was able to cut wood without major drama!

Returning to the 3D-printed concept, [Ivan] suspected reducing the surface speed of the cutting disc could reduce friction-induced heating. This would allow the 3D-printed blade to cut wood without melting, in theory. To achieve this, he built his own basic drop saw using a steel frame and a brushless motor. With a little water spray, and careful control of speed and pressure, the blade was able to slowly chew through a plank of wood. Afterwards, the teeth were almost completely worn down.

The fact is, 3D-printed blades are usually going to be too soft to do any real useful work. However, it’s fun to watch, and that’s good enough for us. If you want something more useful though, consider building your own knives.

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3D Printable Scope Probe Adapts To Your Needs

October 21, 2021 by Dave Rowntree 18 Comments

If there’s one this we electronics engineers are precious about, it’s our test gear. The instruments themselves can be obscenely expensive, since all that R&D effort needs to be paid back over a much smaller user base compared to say a DVD player. The test probes themselves can often come with an eye-watering price tag as well. Take the oscilloscope probe, pretty much everyone who tinkers with hardware will be familiar with. It’s great for poking around, looking desperately for inspiration when you’re getting stuck in with some debug, but you’ve only got two hands, and that doesn’t leave any spare for button pushing.

Hands-free probing solutions exist, but they can be pricey, flimsy or just a pain to use. Sometimes you just want to solder a wire and leave the probe attached, hoping the grounding lead doesn’t fall off and short something. We’ve seen many solutions to this, so here’s yet another one you can 3D print yourself, so it’s almost free to make.

The two-part 3D printed assembly embeds a pair of wires with a Molex 0008500113 sprung terminal on one end, which can be terminated with your choice of pins, headers or just a pair of plain ‘ol wires. Once you’ve dropped your wiring of choice inside, simply glue the halves with a little cyanoacrylate and you’re good to go. Designed around the Siglent 200MHz PP215 specifically, it is likely compatible with many other brands. Thingiverse only has STL files (sigh!) so it may be tricky to adapt it to your exact probe dimensions, but the idea is good at least.

There is no shortage of electronics probing solutions out there, and boy have we covered a few over the years, here’s a low-cost current probe, an Open Source 2 GHz scope probe, and if you want to get really hacky, look no further for inspiration than the 2019 Hackaday SuperCon SMD Challenge.

Thanks [daniel] for the tip!

Spinning Threads Put The Bite On Filament In This Novel Extruder Design

October 20, 2021 by Dan Maloney 29 Comments

When it comes to innovation in FDM 3D printing, there doesn’t seem to be much room left to move the needle. Pretty much everything about filament printing has been reduced to practice, with more or less every assembly available off the shelf. Even the business end — the extruder — is so optimized that there’s not much room left for innovation.

Or is there? The way [David Leitner] sees it, there is, which is why he built this rolling-screw extruder (if you can get to the Thingiverse link, [David] cross-posted on reddit, too). Standard extruders work on the pinch-roller principle, where the relatively soft filament is fed past a spring-loaded gear attached to a stepper motor. The stepper rotates the gear, which either advances the filament into or retracts it from the hot end. [David]’s design instead uses a trio of threaded rods mounted between two rings. The rods are at an angle relative to the central axis of the rings, forming a passage that’s just the right size for the filament to fit in. When the rings spin, the threads on the rods engage with the filament, gripping it around its whole circumference and advancing or retracting it depending on which way it’s spinning. The video below shows it working; we have to admit it’s pretty mesmerizing to watch.

[David] himself admits there’s not much advantage to it, perhaps other than a lower tendency to skip since the force is spread over the entire surface of the filament rather than just a small pinch point. Regardless, we like the kind of thinking that leads to something like this, and we’ll bet there are probably unseen benefits to it. And maybe the extruder actually is a place for innovation after all; witness this modular nozzle swapping system.

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