Maker Faire NY: Cocoa Press Chocolate Printer

If you haven’t figured it out by now, the hype over desktop filament printers is pretty much over. But that doesn’t mean there aren’t new avenues worth exploring that use the basic FDM printer technology. If anything, the low cost and high availability of 3D printer parts and kits makes it easier to branch off into new territory. For example, experimenting with other materials which lend themselves to being “printed” layer by layer like a thermoplastic. Materials such as cement, clay, or even chocolate.

[Evan Weinstein] brought his Cocoa Press printer to the 2018 World Maker Faire in New York, and we have to say it’s a pretty impressive piece of engineering. Hackers have been known to throw a syringe-based paste extruder onto a regular 3D printer and try their luck with squirting out an edible object from time to time, but the Cocoa Press is truly a purpose built culinary machine.

Outwardly it features the plywood case and vaguely Makerbot-looking layout that we’ve seen plenty of times before in DIY 3D printers. It even uses the same RAMPS controller running Marlin that powers your average homebrew printer. But beyond these surface similarities, the Cocoa Press has a number of purpose-built components that make it uniquely qualified to handle the challenges of building with molten chocolate.

For one, beyond the nozzle and the walls of the syringe, nothing physically comes into contact with the chocolate to be printed; keeping the mess and chance of contamination to a minimum. The leadscrew actuated plunger used in common paste extruders is removed in favor of a purely air powered system: a compressor pumps up a small reservoir tank with filtered and dried air, and the Marlin commands which would normally rotate the extruder stepper motor are intercepted and used to trigger an air valve. These bursts of pressurized air fill the empty area above the chocolate and force it out of the 0.8 mm nozzle.

In a normal 3D printer, the “melt zone” is tiny, which allows for the heater itself to be relatively small. But that won’t work here; the entire chocolate load has to be liquefied. It’s a bit like having to keep a whole roll of PLA melted during the entire print. Accordingly, the heater on the Cocoa Press is huge, and [Evan] even has a couple spare heaters loaded up with chocolate syringes next to the printer so he can keep them warm until they’re ready to get loaded up.

Of course, getting your working material hot in a 3D printer is only half the battle, you also need to rapidly cool it back down if you want it to hold its shape as new layers are placed on top of it. A normal 3D printer can generally get away with a little fan hanging next to the nozzle, but [Evan] found the chocolate needed a bit of a chill to really solidify.

So he came up with a cooling system that makes use of water-cooled Peltier units. The cold side of the Peltier array is inside a box through which air is forced, which makes its way through an insulated hose up to the extruder, where a centrifugal fan and 3D printed manifold direct it towards the just-printed chocolate. He reports this system works well under normal circumstances, but unusually high ambient temperatures can overwhelm the cooler.

While “the man” prevented show goers from actually eating any of the machine’s creations (to give out food in New York, you must first register with the city), they certainly looked fantastic, and we’re interested in seeing where the project goes from here.

Hybrid 3D-Printer Creates Complete Circuits, Case and All

The cool kids these days all seem to think we’re on the verge of an AI apocalypse, at least judging by all the virtual ink expended on various theories. But our putative AI overlords will have a hard time taking over the world without being able to build robotic legions to impose their will. That’s why this advance in 3D printing that can incorporate electronic circuits may be a little terrifying, at least to some.

The basic idea that [Florens Wasserfall] and colleagues at the University of Hamburg have come up with is a 3D-printer with a few special modifications. One is a separate extruder than squirts a conductive silver-polymer ink, the other is a simple vacuum tip on the printer extruder for pick and place operations. The bed of the printer also has a tray for storing SMD parts and cameras for the pick-and-place to locate parts and orient them before placing them into the uncured conductive ink traces.

The key to making the hardware work together though is a toolchain that allows circuits to be integrated into the print. It starts with a schematic in Eagle, which joins with the CAD model of the part to be printed in a modified version of Slic3r, the open-source slicing package. Locations for SMD components are defined, traces are routed, and the hybrid printer builds the whole assembly at once. The video below shows it in action, and we’ve got to say it’s pretty slick.

Sure, it’s all academic for now, with simple blinky light circuits and the like. But team this up with something like these PCB motors, and you’ve got the makings of a robotic nightmare. Or not.

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3D Printering: Print Smoothing Tests with UV Resin

Smoothing the layer lines out of filament-based 3D prints is a common desire, and there are various methods for doing it. Besides good old sanding, another method is to apply a liquid coating of some kind that fills in irregularities and creates a smooth surface. There’s even a product specifically for this purpose: XTC-3D by Smooth-on. However, I happened to have access to the syrup-thick UV resin from an SLA printer and it occurred to me to see whether I could smooth a 3D print by brushing the resin on, then curing it. I didn’t see any reason it shouldn’t work, and it might even bring its own advantages. Filament printers and resin-based printers don’t normally have anything to do with one another, but since I had access to both I decided to cross the streams a little.

The UV-curable resin I tested is Clear Standard resin from a Formlabs printer. Other UV resins should work similarly from what I understand, but I haven’t tested them.

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3D-Printed Punch and Die Stand up to Steel

When you think of machine tooling, what comes to mind might be an endmill made of tungsten carbide or a punch and die made of high-speed steel. But surely there’s no room in the machine tool world for 3D-printed plastic tools, especially for the demanding needs of punching parts from sheet metal.

As it turns out, it is possible to make a 3D-printed punch and die set that will stand up to repeated use in a press brake. [Phil Vickery] decided to push the tooling envelope to test this, and came away pleasantly surprised by the results. In fairness, the die he used ended up being more of a composite between the carbon-fiber nylon filament and some embedded metal to reinforce stress points in the die block. It looks like the punch is just plastic, though, and both were printed on a Markforged Mark 2, a printer specifically designed for high-strength parts. The punch and die set were strong enough to form 14-gauge sheet steel in a press brake, which is pretty impressive. The tool wasn’t used to cut the metal; the blanks were precut with a laser before heading to the press. But still, having any 3D-printed tool stand up to metal opens up possibilities for rapid prototyping and short production runs.

No matter what material you make your tooling out of, there’s a lot to know about bending metal. Check out the basics in our guide to the art and science of bending metal.

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Heated DryBox Banishes Filament Moisture for Under $20

There has been a lot of activity from [Richard Horne] regarding 3D printing filaments lately; most recently he has shared two useful designs for upping one’s filament storage and monitoring game. The first is for a DIY Heated DryBox for 3D printing filament. It keeps filament dry not just by sealing it into a plastic box with some desiccant, but by incorporating a mild and economical heater intended for reptile habitats inside. Desiccant is great, but a gently heated enclosure can do wonders for driving away humidity in the right environment. The DryBox design also incorporates a handy little temperature and humidity sensor to show how well things are working.

Spool-mounted adapter for temperature and humidity sensor (and desiccant) to monitor storage bag conditions.

The second design is a simple spin-off that we particularly liked: a 3D printed adapter that provides a way to conveniently mount one of the simple temperature and humidity sensors to a filament spool with a desiccant packet. This allows storing a filament spool in a clear plastic bag as usual, but provides a tidy way to monitor the conditions inside the bag at a glance. The designs for everything are on Thingiverse along with the parts for the Heated DryBox itself.

[Richard] kindly shares the magic words to search for on eBay for those seeking the build’s inexpensive key components: “15*28CM Adjustable Temperature Reptile Heating Heater Mat” and “Mini LCD Celsius Digital Thermometer Hygrometer Temperature Humidity Meter Gauge”. There are many vendors selling what are essentially the same parts with minor variations.

Since the DryBox is for dispensing filament as well as storing it, a good spool mounting system is necessary but [Richard] found that the lack of spool standardization made designing a reliable system difficult. He noted that having spool edges roll on bearings is a pretty good solution, but only if one doesn’t intend to use cardboard-sided spools, otherwise it creates troublesome cardboard fluff. In the end, [Richard] went with a fixed stand and 3D printable adapters for the spools themselves. He explains it all in the video, embedded below.

Continue reading “Heated DryBox Banishes Filament Moisture for Under $20”

Ingenious use of 3D Printer gives Simba the Mane he deserves

Here at Hackaday, we love clever 3D prints. This amazing lion statue remixed by [ _primoz_], makes us feel no different. It is no secret that FDM 3D printers have come a long way, propelled by the enthusiastic support from the open source community.

However, FDM 3D printers have some inherent limitations; some of which arise from a finite print nozzle diameter, tracing out the 3D object layer by layer. Simply put, some print geometries and dimensions are just unattainable. We discussed the solution to traditional FDM techniques being confined to Planer layers only in a previous article.

The case in point here is a 3D printed lion whose original version did not fully capture its majestic mane. [_primoz_] solution was to construct a support cylinder around the head and form the actual hair as a series of planar bristles, which were one extrusion wide.

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This was followed by some simple post processing, where a heat gun was used to form the bristles into a dapper mane.

The result is rather glorious and we can’t wait for someone to fire up a dual extruder and bring out the flexible filament for this print!

[via Thingiverse]

Songbird, A Mostly 3D Printed Pistol That Appears To Actually Work

[Guy in a garage] has made a 3D printed gun that not only appears to fire in the direction pointed, it can also do it multiple times. Which, by the standard of 3D printed guns, is an astounding feat. He started with .22 rifle cartridges but has since upgraded and tested the gun with .357 rounds. The link above is a playlist which starts of with an in-depth explanation of the .22 version and moves through design iterations

This gun prints on a standard FDM printer. Other 3D printable guns such as the infamous Liberator or the 3D printed metal gun need more exotic or precise 3D printing to work effectively. The secret to this gun’s ability is the barrel, which can be printed in nylon for .22 cartridges, or in ABS plus a barrel liner for .22 and .357 caliber.

A barrel liner is one way to repair a gun that has aged and is no longer shooting properly. Simply put, it is a long hardened metal tube with rifling on the inside. Some guns come out of the factory with one, and a gunsmith simply has to remove the old one and replace it. Other guns need to be bored out before a liner can be installed.

The metal liner surrounded by plastic offers enough mechanical strength for repeat firings without anyone losing a hand or an eye; though we’re not sure if we recommend firing any 3D printed gun as it’s still risky business. It’s basically like old stories of wrapping a cracked cannon in twine. The metal tries to expand out under the force of firing, but the twine, which would seem like a terrible material for cannon making, is good in tension and when wrapped tightly offers more than enough strength to hold it all together.

This is also how he got the .357 version to work. The barrel slots into the gun frame and locates itself with a rounded end. However, with the higher energy from a .357 round, this rounded end would act as a wedge and split the 3D printed frame. The fix for this was simple. Glue it back together with ABS glue, and then wrap the end of the assembly with a cable tie.

This is the first 3D printed gun we’ve seen that doesn’t look like a fantastic way to instantly lose your hand. It’s a clever trick that took some knowledge of guns and gunsmithing to put together. Despite the inevitable ethical, moral, and political debate that will ensue as this sort of thing becomes more prevalent, it is a pretty solid hack and a sign that 3D printing is starting to work with more formidable engineering challenges.