Prusa Picks Up The Pace With New MK4S Printer

August 12, 2024 by Tom Nardi 28 Comments

One of the things you’re paying for when you buy a 3D printer from Prusa Research is, essentially, your next 3D printer. That’s because Prusa’s machines are designed to be upgraded and modified as time goes on. An upgrade kit is always released to allow each older printer to be converted into its successor, and while there’s occasionally been some debate about whether or not it’s the most cost-effective choice, at least it is a choice you have as an owner.

If you’ve got a Prusa MK4, you’ll soon get to make that decision for yourself. Announced earlier today, the new MK4S brings some notable changes to last year’s printer. The $99 upgrade is scheduled to be available by the end of the month for existing owners, but if you’ve been on the fence about joining Team Orange and Black, you can purchase the MK4S right now in both kit and assembled forms for the same price ($799 and $1,099 respectively) as the previous MK4.

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3D Printed Jet Engine Goes Turbo

August 10, 2024 by Al Williams 11 Comments

Printing a model jet engine is quite an accomplishment. But it wasn’t enough for [linus3d]. He wanted to redesign it to have a turbojet, an afterburner, and a variable exhaust nozzle. You can see how it all goes together in the video below.

This took months of work and it shows. This probably won’t make a good rainy-day weekend project. You do need a few ball bearings and some M2 hardware, but it is mostly 3D printed.

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Liquid (Reversibly) Solidifies At Room Temperature, Gets Used For 3D Prints

August 9, 2024 by Donald Papp 8 Comments

Researchers demonstrate sustainable 3D printing by using poly(N-isopropylacrylamide) solutions (PNIPAM), which speedily and reliably turn solid by undergoing a rapid phase change when in a salt solution.

This property has been used to 3D print objects by using a syringe tip as if it were a nozzle in a filament-based printer. As long as the liquid is being printed into contact with a salt solution, the result is a polymer that solidifies upon leaving the syringe.

What’s also interesting is that the process by which the PNIPAM-based solutions solidify is entirely reversible. Researchers demonstrate printing, breaking down, then re-printing, which is an awfully neat trick. Finally, by mixing different additives in with PNIPAM, one can obtain different properties in the final product. For example, researchers demonstrate making conductive prints by adding carbon nanotubes.

While we’ve seen the concept of printing with liquids by extruding them into a gel bath or similar approach, we haven’t seen a process that prides itself on being so reversible before. The research paper with all the details is available here, so check it out for all the details.

Magnesium And Copper Makes An Emergency Flashlight

August 8, 2024 by Lewin Day 17 Comments

Many of us store a flashlight around the house for use in emergency situations. Usually, regular alkaline batteries are fine for this task, as they’ll last a good few years, and you remember to swap them out from time to time. Alternatively, you can make one that lasts virtually indefinitely in storage, and uses some simple chemistry, as [JGJMatt] demonstrates.

The flashlight uses 3D printing to create a custom battery using magnesium and copper as the anode and cathode respectively. Copper tape is wound around a rectangular part to create several cathode plates, while magnesium ribbon is affixed to create the anodes. Cotton wool is then stuffed into the 3D-printed battery housing to serve as a storage medium for the electrolyte—in this case, plain tap water.

The custom battery is paired with a simple LED flashlight circuit in its own 3D-printed housing. The idea is that when a blackout strikes, you can assemble the LED flashlight with your custom battery, and then soak it in water. This will activate the battery, producing around 4.5 V and 20 mA to light the LED.

It’s by no means going to be a bright flashlight, and realistically, it’s probably less reliable than just keeping a a regular battery-powered example around. Particularly given the possibility of your homebrew battery corroding over the years unless it’s kept meticulously dry. But that’s not to say that water-activated batteries don’t have their applications, and anyway it’s a fun project that shows how simple batteries really are at their basic level. Consider it as a useful teaching project if you have children interested in science and electricity!

Benchy In A Bottle

August 6, 2024 by Matthew Carlson 20 Comments

Making something enjoyable often requires a clever trick. It could be a way to cut something funny or abuse some peripheral in a way it was never designed for. Especially good tricks have a funny way of coming up again and again. [DERAILED3D] put a 3d printed benchy in a bottle with one of the best tricks 3d printing has.

The trick is stopping the print part way through and tweaking it. You can add manual supports or throw in some PTFE beads to make a generator. The benchy isn’t the print being paused; the bottle is. The benchy is a standard print, and the bottle is clear resin. Once halfway through, they paused the print, and the benchy was left suspended in the bottle with a bit of wire. Of course, [DERAILED3D] moved quickly as they risked a layer line forming on the delicate resin after a minute or two of pausing. The difficulty and mess of tweaking a gooey half-finished resin print is likely why we haven’t seen many attempts at playing with the trick, but we look forward to more clever hacks as it gets easier.

The real magic is in the post-processing of the bottle to make it look as much like glass as possible. It’s a clever modern twist on the old ship in the bottle that we love. Video after the break.

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Need Many Thin Parts? Try Multi-material Stack Printing

July 27, 2024 by Elliot Williams 9 Comments

Admittedly it’s a bit of a niche application, but if you need lots of flat 3D printed objects, one way to go about it is to print them in a stack and separate them somehow. An old(er) solution is to use a non-extruding “ironing” step between each layer, which makes them easier to pull apart. But another trick is to use the fact that PLA and PETG don’t stick well to each other to your advantage. And thus is born multi-material stack printing. (Video, embedded below the break.)

[Jonathan] wants to print out multiples of his fun Multiboard mounting system backplates, and these are the ideal candidate for stack printing: they’re thin, but otherwise take up the entire build plate. As you’d expect, the main trick is to print thin layers of PETG between the PLA plate layers that you do want. He demonstrates that you can then simply pull them apart.

There are some tricks, though. First is to make two pillars in addition to the plates, which apparently convinces the slicer to not flatten all the layers together. (We don’t really understand why, honestly, but we don’t use Bambu slicer for multi-materials.) The other trick that we expect to be more widely applicable, is that [Jonathan] extrudes the PETG interlayers a little thicker than normally. Because the PETG overflows the lower PLA layer, it physically locks on even though it chemically doesn’t. This probably requires some experimentation.

As multi-material printers get cheaper, we’ve seen a lot more innovative uses for them popping up. And we wouldn’t be so stoked about the topic if there weren’t a variety of hacker projects to make it possible. Most recently, the impressive system from [Armored_Turtle] has caught our eye. Who knows what kind of crazy applications we’ll see in the future? Are you doing multi-material yet?

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Electromagnetic Actuator Mimics Muscle

July 26, 2024 by Lewin Day 11 Comments

Most electromagnetic actuators are rotating motors, or some variation on the theme, like servos. However, it’s possible to do linear actuation with electomagnetics, too. [Adrian Perez] demonstrates this with Linette, his design of a linear actuator that he was inspired to build by the structure of our own muscles.

The design uses a coil of copper wire in a 3D-printed plastic housing, surrounded by a claw full of strong magnets. When the coil is activated, the magnets are pulled towards the coil. When the coil is not energized, the magnets fall away. [Adrian] demonstrates the actuator under the control of an Arduino, which switches power to the coil to move it up and down.

He also notes that the design is similar solenoids and voice coil style actuators, though unlike most his uses discrete magnets rather than a single monolithic magnet. It’s possible to get more capacity out of the Linette design through stacking. You can parallelize the actuators to get more pulling force, with neighboring coils sharing the same magnets. Alternatively, you can stack them in series to get longer stroke lengths.

[Adrian] hasn’t put the design to a practical application yet, but we could see multiple uses for robotics or small machines. We’ve seen some other neat DIY magnetic actuators before, too. Video after the break.