Adding Recycling Codes To 3D Prints

Every little plastic bauble you interact with has some sort of recycling code on it somewhere. Now that we’re producing plastic 3D printed parts at home, it would be a good idea to agree on how to recycle all those parts, and [Joshua Pearce]’s lab at Michigan Tech has the answer; since we’re printing these objects, we can just print the recycling code right in the object.

The US system of plastic recycling codes is particularly ill-suited for identifying what kind of plastic the object in question is made of; there are only seven codes, while China’s system of plastic identification uses 140 identification codes. This system for labeling 3D printed parts borrows heavily from the Chinese system, assigning ABS as ‘9’, PLA as ’92’, and HIPS as ‘108’.

With agreed upon recycling codes, the only thing left to do is to label every print with the correct recycling code. That’s an easy task with a few OpenSCAD scripts – the paper shows off a wrench made out of HIPS labeled with the correct code, and an ABS drill bit handle sporting a number nine. 3D printing opens up a few interesting manufacturing techniques, and the research team shows this off with a PLA vase with a recycle code lithophane embedded in the first few layers.

3D Printering: Induction Heating

Every filament-based 3D printer you’ll find today heats plastic with resistive heaters – either heater cartridges or big ‘ol power resistors. It’s efficient, but that will only get you so far. Given these heaters can suck down only so many Watts, they can only heat up so fast. That’s a problem, and if you’re trying to make a fast printer, it’s also a limitation.

Instead of dumping 12 or 24 VDC into a resistive heater, induction heaters passes high-frequency AC through a wire that’s inductively coupled to a core. It’s also very efficient, but it’s also very fast. No high-temperature insulation is required, and if it’s designed right, there’s less thermal mass. All great properties for fast heating of plastic.

A few years ago, [SB] over on the RepRap blog designed an induction heater for a Master’s project. The hot end was a normal brass nozzle attached to a mild steel sleeve. A laminated core was attached to the hot end, and an induction coil wrapped around the core. It worked, but there wasn’t any real progress for turning this into a proper nozzle and hot end. It was, after all, just a project.

Finally, after several years, people are squirting plastic out of an induction heated nozzle. [Z], or [Bulent Unalmis], posted a project to the RepRap forums where he is extruding plastic that has been heated with an induction heater. It’s a direct drive system, and mechanically, it’s a simpler system than the fancy hot ends we’re using now.

Electronically, it’s much more complex. While the electronics for a resistive heater are just a beefy power supply and a MOSFET, [Z] is using 160 kHz AC at 30 V. That’s a much more difficult circuit to stuff on a printer controller board.

This could be viewed as just a way of getting around the common 24V limitation of common controller boards; shove more power into a resistor, and it’s going to heat faster. This may not be the answer to hot ends that heat up quicker, but at the very least it’s a very neat project, and something we’d like to see more of.

You can see [Z]’s video demo of his inductive hot end below. Thanks [Matt] for the tip.

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New RepRap With Integrated Case, Oddly Called Case-Rap

The great thing about RepRaps are that there are so many to choose from! No matter what features or design intent you could want, there is probably a RepRap for that. Even so, there has been a recent addition to the RepRap family. Creator [jlguil] calls it the Case-Rap, and for good reason, the frame of the printer folds up into a suitcase.

The Case-Rap is inspired by the Mendel90 which tries to improve on the original Mendel by replacing the threaded rods for a more rigid sheet material frame with bracing to keep the X, Y and Z axes perpendicular to each other. The Case-Rap goes a little further with the design to have the frame also perform double duty as a travel case.

Check out the video after the break, the printer is actually built in 2 complete separate assemblies. The X and Z axes are mounted in a 4-sided wooded frame. The Y axis and the electronics are mounted on a 2-sided wooden frame. When the frame pieces are latched together in one orientation, they conceal the printer inside a suitcase-sized box. The latch positions were thoughtfully placed so the frame pieces could also be latched together in ‘printer mode’. Setting up and breaking down the printer takes all of 30 seconds.

You may think a super portable printer has to be small… but you’d be wrong. The Case-Rap has a commendable 8x8x8 inch print area. According to [jlguil], the total DIY cost comes in around 350$ CAD, which is not too bad for a 3D printer, and pretty good for one that is unique, portable and capable.

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Hackaday Links: March 8, 2015

Nintendo is well known for… odd… hardware integration, but this video takes it to a new level. It’s a Gamecube playing Zelda: Four Swords Adventure, a game that can use a Game Boy Advance as a controller. [fibbef] is taking it further by using the Gamecube Game Boy Advance player to play the game, and using another GBA to control the second Gamecube. There’s also a GBA TV tuner, making this entire setup a Gamecube game played across two Gamecubes, controlled with a Game Boy Advance and displayed on a GBA with a TV tuner. The mind reels.

TI just released a great resource for analog design. It’s the Analog Engineer’s Pocket Reference, free for download, if you can navigate TI’s site. There are print copies of this book – I picked one up at Electronica – and it’s a great benchtop reference.

A few months ago, a life-size elephant (baby elephants are pretty small…) was 3D printed at the Amsterdam airport. A model of the elephant was broken up into columns about two meters tall. How did they print something two meters tall? With this add-on for a Ultimaker. It flips an Ultimaker upside down, giving the printer unlimited build height. The guy behind this – [Joris van Tubergen] – is crazy creative.

And you thought TV was bad now. Here’s the pitch: take a show like Storage Wars or American Pickers – you know, the shows that have people go around, lowball collectors, and sell stuff on the Internet – and put a “Tech” spin on it. This is happening. That’s a post from a casting producer on the classic cmp message boards. Here’s the vintage computer forums reaction. To refresh your memory, this is what happens when you get ‘tech’ on Storage Wars. Other examples from Storage Wars that include vastly overpriced video terminals cannot be found on YouTube. Here’s a reminder: just because it’s listed on eBay for $1000 doesn’t mean it’ll sell on eBay for $1000.

Checking Populated PCB Clearance with a 3D Printer

Laying out one PCB, sending it out to a fab, stuffing it with components, and having the whole thing actually work when you’re done is a solved problem. Doing the same thing and having it plug in to another PCB… well, that’s a bit harder. Forget about building a PCB and having it fit inside an enclosure the first time.

The usual solution to this problem is printing the board to be fabbed on a piece of paper, take some calipers, and measure very, very carefully. Extra points for sticking a few components you’re worried about to the paper before lining the mechanical prototype up to the existing board. [N8VI] over at the i3 Detroit hackerspace had a better idea – print the whole thing out on a 3D printer.

[N8VI] is working on a software defined radio cape for a BeagleBone. He was a bit concerned about a few caps getting in the way of a board stack. This was tested by printing out a bit of plastic in the shape of the new board, adding header spacers and parts that might be troublesome.

While the idea is great, there’s not much in the way of a software solution or a toolchain to make plastic copies of completed boards. We know rendering 3D objects from KiCAD is rather easy, but there aren’t many tools available for those of us who are still stuck with Eagle. If you know of a way to print populated boards, drop a note in the comments.

3D Printed Fish Feeder

[Helios Labs] recently published version two of their 3D printed fish feeder. The system is designed to feed their fish twice a day. The design consists of nine separate STL files and can be mounted to a planter hanging above a fish tank in an aquaponics system. It probably wouldn’t take much to modify the design to work with a regular fish tank, though.

The system is very simple. The unit is primarily a box, or hopper, that holds the fish food. Towards the bottom is a 3D printed auger. The auger is super glued to the gear of a servo. The 9g servo is small and comes with internal limiters that only allow it to rotate about 180 degrees. The servo must be opened up and the limiters must be removed in order to enable a full 360 degree rotation. The servo is controlled by an Arduino, which can be mounted directly to the 3D printed case. The auger is designed in such a way as to prevent the fish food from accidentally entering the electronics compartment.

You might think that this project would use a real-time clock chip, or possibly interface with a computer to keep the time. Instead, the code simply feeds the fish one time as soon as it’s plugged in. Then it uses the “delay” function in order to wait a set period of time before feeding the fish a second time. In the example code this is set to 28,800,000 milliseconds, or eight hours. After feeding the fish a second time, the delay function is called again in order to wait until the original starting time.

How I Learned to Stop Worrying and Love My 3D Printer

So, you’re thinking about finally buying a 3D printer? All the cool kids have one. Plus, how hard can it be anyways? Well, before you pull the trigger, it might be best to read this cautionary tale of one user’s experience in getting started with his first 3D printer.

[Scott Hanselman] is a programmer and teacher who started out with zero knowledge of 3D printing. In his informative (and somewhat humorous) blog post, you can follow along with [Scott] hour-by-hour as he unravels the some of the common mysteries that almost everyone will encounter with their first 3D printer.

His adventure begins with the frustration of z-axis calibration, an important part of any 3D printer. Some of the newer printers are automating this step (as well as bed-leveling) with sensors and clever software, but even then it might need small tweaks to lay down the all-important first layer. By hour five with his new printer, this slight annoyance turns into disgruntlement, as he finds that although there is tons of documentation on-line, a lot of it can be outdated or simply unhelpful.

In the end, [Scott] got his printer up and running, and learned a lot along the way.  We bet you can too – with a little effort that is. As the quality of printers on the market keeps going up, and the price continuing to fall for an entry-level printer, now might be the perfect time for you to get started. But you might want to read [Scott’s] journey to help manage your out-of-the-box expectations.