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.

Resuming Failed 3D Prints Automatically

What happens to your 3D printer if the power goes out? What happens if there’s a jam in the nozzle? What happens if your filament breaks, runs out, or turns into a plate of spaghetti? For all these situations, the print fails, wasting plastic and time. For his Hackaday Prize entry, [robert] has come up with a tiny device that saves all those failed prints, and it does it without batteries or a UPS.

The idea behind [robert]’s box is to monitor all the G-code being sent to the printer, and allow a print to be resumed after a failure. The design is simple enough — just a USB mini port on one end, a USB A port on the other, and three buttons in between. This box logs the G-code, and if the printer happens to fail, the box will spring into life allowing you to resume a print from any Z position.

Already [robert] has tested this box on a number of printers including the Prusa i3, the Creality CR-10, and the ever-popular, explodey Anet A8. The project has already gone through a few hardware revisions and there is, of course, a fancy 3D printed enclosure for the board. It’s a great project, and one of the more interesting 3D printing tools we’ve seen in this year’s Hackaday Prize.

A Crash Sensor For Delta 3D Printers

It doesn’t happen that often, but this is the last time that [Lucas] comes back from hours of unattended 3D printing to find a large portion of plastic spaghetti mess and a partly disassembled Kossel. The crash sensor he designed will now safely halt the printer if it detects that something went wrong during the print.

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Open-Source Laser Cutter Software gets Major Update, New Features

The LaserWeb project recently released version 3, with many new features and improvements ready to give your laser cutter or engraver a serious boost in capabilities! On top of that, new 3-axis CNC support means that the door is open to having LaserWeb do for other CNC tools what it has already done for laser cutting and engraving.

LaserWeb BurnsLaserWeb3 supports different controllers and the machines they might be connected to – whether they are home-made systems, CNC frames equipped with laser diode emitters (such as retrofitted 3D printers), or one of those affordable blue-box 40W Chinese lasers with the proprietary controller replaced by something like a SmoothieBoard.

We’ve covered the LaserWeb project in the past but since then a whole lot of new development has been contributed, resulting in better performance with new features (like CNC mode) and a new UI. The newest version includes not only an improved ability to import multiple files and formats into single multi-layered jobs, but also Smoothieware Ethernet support and a job cost estimator. Performance in LaserWeb3 is currently best with Smoothieware, but you can still save and export GCODE to use it with Grbl, Marlin, EMC2, or Mach3.

The project is open to contributions from CNC / Javascript / UX developers to bring it to the next level. If you’re interested in helping bring the project even further, and helping it do for 3-axis CNC what it did for Laser Cutting, project coordinator [Peter van der Walt] would like you to head to the github repository!

We recently shared a lot of great information on safe homebrew laser cutter design. Are you making your own laser cutting machine, or retrofitting an existing one? Let us know about it in the comments!

Build A 3D Printer Workhorse, Not an Amazing Disappointment Machine

3D printers have become incredibly cheap, you can get a fully workable unit for $200 – even without throwing your money down a crowdfunded abyss. Looking at the folks who still buy kits or even build their own 3D printer from scratch, investing far more than those $200 and so many hours of work into a machine you can buy for cheap, the question “Why the heck would you do that?” may justifiably arise.

The answer is simple: DIY 3D printers done right are rugged workhorses. They work every single time, they never break, and even if: they are an inexhaustible source of spare parts for themselves. They have exactly the quality and functionality you build them to have. No clutter and nothing’s missing. However, the term DIY 3D printer, in its current commonly accepted use, actually means: the first and the last 3D printer someone ever built, which often ends in the amazing disappointment machine.

This post is dedicated to unlocking the full potential in all of these builds, and to turning almost any combination of threaded rods and plywood into a workshop-grade piece of equipment.

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Heating Up a Printrbot’s Bed

A heated bed for the Printrbot 3D printer

Heated beds for 3D printers help reduce the amount of curling and warping of parts. The warping happens when the part cools and contracts. The heated bed keeps the part warm for the entire print and reduces the warping.

As an upgrade to her Printrbot, [Erin] added a heated bed. The first plan was to DIY one using Nichrome wire, but heated beds are available at low cost. They’re basically just a PCB with a long trace that acts as a resistor. She added a thermistor to monitor temperature and allow for accurate control.

The Printrbot heated bed worked, but didn’t heat up quite quick enough. [Erin] was quick to scratch off the solder mask and solder new leads onto the board. This converted the board into two parallel resistors, halving the resistance and doubling the power.

This version heated up very quickly, but didn’t have a steady heat. The simple control that was being used was insufficient, and a PID controller was needed. This type of control loop helps deal with problems such as oscillations.

The Printrbot’s firmware is based on Marlin, which has PID support disabled by default. After rebuilding the code and flashing, the PID gains could be adjusted using g-codes. With the values tuned, [Erin]’s printer was holding steady heat, and can now print ABS and PLA with minimal warping.