3D Printing Without Support

3D printing is getting better every year, a tale told by dozens of Makerbot Cupcakes nailed to the wall in hackerspaces the world over. What was once thought impossible – insane bridging, high levels of repeatability, and extremely well-tuned machines – are now the norm. We’re still printing with supports, and until powder printers make it to garages, we’ll be stuck with that. There’s more than one way to skin a cat, though. It is possible to print complex 3D objects without supports. How? With pre-printed supports, of course.

[Markus] wanted to print the latest comet we’ve landed on, 67P/Churyumov–Gerasimenko. This is a difficult model for any 3D printer: there are two oversized lobes connected by a thin strand of comet. There isn’t a flat space, either, and cutting the model in half and gluing the two printed sides together is certainly not cool enough.

To print this plastic comet without supports, [Markus] first created a mold – a cube with the model of the comet subtracted with a boolean operation. If there’s one problem [Markus] ran into its that no host software will allow you to print an object over the previous print. That would be a nice addition to Slic3r or Repetier Host, and shouldn’t be that hard to implement.

Locking A Beer With A 3D Printer

Have a nice, refreshing IPA sitting in the fridge along with a ton of other beers that have ‘Light’ or ‘Ice’ in their name? Obviously one variety is for guests and the other is for hosts, but how do you make sure the drunkards at your house tell the difference? A beer bottle lock, of course.

Because all beer bottles are pretty much a standard size, [Jon-A-Tron] was able to create a small 3D printed device that fit over the bottle cap. The two pieces are held together with a 4-40 hex screw, and the actual lock comes from a six-pack of luggage padlocks found at the hardware store.

It’s a great device to keep the slackers away from the good stuff, and also adds a neat challenge to anyone that’s cool enough to know basic lock picking. Of course, anyone with a TSA master key can also open the beer lock, but if you’re hosting a party with guest who frequently carry master keys around with them, you’re probably having too good of a time to care.

Nanobots Swim like Scallops in Non-Newtonian Fluids

The idea of using nanobots to treat diseases has been around for years, though it has yet to be realized in any significant manner. Inspired by Purcell’s Scallop theorem, scientists from the Max Planck Institute for Intelligent Systems have created their own version . They designed a “micro-scallop” that could propel itself through non-Newtonian fluids, which is what most biological fluids happen to be.

The scientists decided on constructing a relatively simple robot, one with two rigid “shells” and a flexible connecting hinge. They 3D-printed a negative mold of the structure and filled it with a polydimethylsiloxane (PDMS) solution mixed with fluorescent powder to enable detection. Once cured, the nanobot measured 800 microns wide by 300 microns thick. It’s worth noting that it did not have a motor. Once the mold was complete, two neodymium magnets were glued onto the outside of each shell. When a gradient-free external magnetic field was applied, the magnets make the nanobot’s shells open and close. These reciprocal movements resulted in its net propulsion through non-Newtonian media. The scientists also tested it in glycerol, an example of a Newtonian fluid. Confirming Purcell’s Scallop theorem, the nanobot did not move through the glycerol. They took videos of the nanobot in motion using a stereoscope, a digital camera with a colored-glass filter, and an ultraviolet LED to make the fluorescent nanobot detectable.

The scientists did not indicate any further studies regarding this design. Instead, they hope it will aid future researchers in designing nanobots that can swim through blood vessels and body fluids.  We don’t know how many years it will be before this becomes mainstream medical science, but we know this much: we will never look at scallops the same way again!

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A Tiny Arcade Machine With Tinier Buttons

Building a MAME machine around a Raspberry Pi has been the standard build for years now, and tiny versions of full-sized arcade machines have gone from curiosity to commonplace. [diygizmo] just built one of these tiny arcades, but the fit and finish of this one puts it above all others. There’s a real, miniature joystick in there, along with 3D printed adapters for tact switches to make this one look like a lilliputian version of a full size standup MAME cabinet.

The entire enclosure is 3D printed, and most of the electronics are exactly what you would expect: A Raspberry Pi, 2.5″ LCD, and a battery-powered speaker takes up most of the BOM. Where this build gets interesting is the buttons and joystick: after what we’re sure was a crazy amount of googling, [diygizmo] found something that looks like a normal arcade joystick, only smaller. Unable to find a suitable replacement for arcade buttons, [diygizmo] just printed their own, tucked a tact switch behind the plastic, and wired everything up.

Add in some decals, paint, and the same techniques used to create plastic model miniatures, and you have a perfect representation of a miniature arcade machine.

3D Printing Goes Hand in Hand with Iron Man Inspired Prosthetic

It’s exciting how much 3D printing has enabled us to produce pretty much any shape for any purpose on the fly. Among the most thoughtful uses for the technology that we’ve seen are the many functioning and often beautiful prosthetics that not only succeed in restoring the use of a limb, but also deliver an air of style and self-expression to the wearer. The immediate nature of the technology allows for models to be designed and produced rapidly at a low-cost, which works excellently for growing children. [Pat Starace’s] Iron Man inspired 3D printed hand and forearm are a perfect example of such personality and expert engineering… with an added dash of hacker flair.

With over twenty years of experience in animatronics behind him, [Starace] expertly concealed all of the mechanical ligaments within the design of his arm, producing a streamline limb with all the nuance of lifelike gesture. It was important that the piece not only work, but give the wearer that appropriate super hero-like feeling while wearing it. He achieves this with all the bells and whistles hidden within the negative space of the forearm, which give the wearer an armory of tricks up their sleeve. Concealed in the plating, [Starace] uses an Arduino and accelerometer to animate different sets of LEDs as triggered by the hand’s position coupled with specific voice commands. Depending on what angle the wrist is bent at, the fingers will either curl into a fist and reveal hidden ‘lasers’ on the back of the hand, or spread open around a pulsing circle of light on the palm when thrust outward.

The project took [Starace] quite a bit of time to print all the individual parts; around two days worth of time. This however is still considered quick in comparison to the custom outfitting and production of traditional prosthetics… not to mention, the traditional stuff wouldn’t have LEDs. This piece has a noble cause, and is an exciting example of how 3D printing is adding a level of heroism to everyday life.

Thank you Julius for pointing out this awesome project to us!

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3D Printing of Parameterized Speaker Enclosures

Despite what you would gather from looking at a mess of wires, carpet, and MDF in the back of a Honda Civic hatchback, building speaker enclosures is a pretty complex business. To get the right frequency response, you’ll need to take into account the driver’s resonant frequency, the volume of any internal components, and how well the speaker works when it reaches the resonant frequency. Heady stuff, but when [Rich] at NothingLabs started 3D printing his own speaker enclosures, he realized he could calculate an ideal enclosure automatically. Ah, the joys of OpenSCAD.

[Rich] wrote a bit of OpenSCAD and put it up on the Thingiverse Customizer, allowing anyone to manually enter a box volume, height and width ratio, size for a speaker hole, and even bass ports.

There are a few really cool features for this way of constructing speaker enclosures; assembly is a snap, and it’s most likely air tight right out of the printer. [Rich] printed an enclosure for a 3″ driver that has a frequency response down to 66Hz – an extremely impressive piece of work. Video below.

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An Electric Arc Printer for Rapid 3D Prototyping

Additive manufacturing, aka 3D printing, is able to produce wonderful and amazing objects in relatively short periods of time. Items are now being created in hours, not days, which is an extraordinary leap in technology. However, waiting for a 3D printer to complete its cycle is still a lot like watching paint dry. It takes way too long, and occasionally, time is of the essence when prototyping products for a client. Sometimes you just need it done now,…not a few hours from now.

[0n37w0] is hoping solve this problem by working on a way to ‘print’ 3D objects using arcs of electricity. We are still trying to wrap our heads around how this will work, but from the looks of it, arc printing “is done by completing an electrical current on an area of granulated metal thus heating the metal enough to form a bond to the structure being printed.

The printer is comprised of four main components (the print bed, the lifting device, the control box, and the granulated metal supply bin). The supply bin feeds granulated metal, possibly by vibration, onto the print bed. A lifting mechanism is then lowered within electrical contact and the printing begins. After each layer, the object is raised.

To find out more, check out the Hackaday.io project page.