Are your 3D Prints Toxic?

With the rising popularity and increasing availability of 3D printers, it was inevitable that someone would start looking into the potential environmental impact presented by them. And now we have two researchers from the University of California Riverside sounding the alarm that certain plastics are toxic to zebrafish embryos (abstract only; full paper behind a paywall).

As is often the case with science, this discovery was serendipitous. Graduate student [Shirin Mesbah Oskui] was using 3D printed tools to study zebrafish embryos, a widely used model organism in developmental biology, but she found the tools were killing her critters. She investigated further and found that prints from both a Stratasys Dimension Elite FDM printer and from a Formlabs Form 1+ stereolithography printer were “measurably toxic” to developing zebrafish embryos. The resin-based SLA printed parts were far worse for the fish than the fused ABS prints – 100% of embryos exposed to the Form 1+ prints were dead within seven days, and the few that survived that long showed developmental abnormalities before they died. Interestingly, the paper also describes a UV-curing process that reduces the toxicity of the SLA prints, which the university is patenting.

Of course what’s toxic to zebrafish is not necessarily a problem for school kids, as the video below seems to intimate. Still, this is an interesting paper that points to an area that clearly needs more investigation.

Continue reading “Are your 3D Prints Toxic?”

3D Printed Quadcopter Props

Here’s something that isn’t quite a hack; he’s just using a 3D printer as a 3D printer. It is extremely interesting, though. Over on [Anton] is creating 3D printable propellers for quadcopters and RC planes. Conventional wisdom says that propellers require exceedingly exacting tolerances, but [Anton] is making it work with the right 3D file and some creative post-processing treatment of his prints.

These 3D printed props are a remix of an earlier project on Thingiverse. In [Anton]’s testing, he didn’t get the expected lift from these original props, so a few small modifications were required. The props fit on his 3D printer bed along their long edge allowing for ease of slicing and removal of support material. For post-processing, [Anton] is using acetone vapor smoothing on his ABS printed design. They come out with a nice glossy sheen, and should be reasonably more aerodynamic than a prop with visible layer lines.

Although [Anton]’s prop is basically a replica of a normal, off-the-shelf quadcopter prop, 3D printing unique, custom props does open up a lot of room for innovation. The most efficient propeller you’ll ever find is actually a single-bladed propeller, and with a lot of experimentation, it’s possible anyone with a well-designed 3D printer could make turn out their own single-blade prop.

Continue reading “3D Printed Quadcopter Props”

3D Printing an Arcade Controller

A keyboard and mouse simply can’t stand in for games originally meant to be played with a joystick and buttons. We are of course thinking of coin-op here and building your own set of arcade controls is a great project to give back some of the thrill of those classics. But these are not trivial builds and may push your comfort zone when it comes to fabrication. Here’s one alternative to consider: 3D printing an arcade controller housing.

3d-printed-arcade-controller-thumb[Florian] already had experience building these using laser cut acrylic and MDF. This is his first foray into a 3D printing build method for the controller body. The top is too large to easily produce as a single piece on inexpensive printers. He broke it up into sections; eleven in total. When the printing is complete he chemically welds them together using a slurry of acetone and leftover ABS.

We think one possible extension of this technique would be to build a mounting system that would allow you to swap out segments (instead of welding them all) while you dial in the exact placement that you want for each component. You know, like when you decide that rectangular button pattern doesn’t fit your hand. That said, this looks like a beautiful and functional build. At the least it’s a great way to practice your 3D printing skills and you end up with a wicked controller at the end of it.

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.

Custom Filaments With A Filastruder

A while ago, when 3D printing was the new hotness, a few people looked around and said, ‘our printers are open source, why can’t we just build the machines that make our 3D printing filament?’ There was a $40,000 prize for the first person to build an open source filament extruder, resulting in a few filament fabrication machines being released into the wild. [Rupin] over in the Mumbi hackerspace has one of these filament extruders – a Filastruder – and decided to take a look at what it could do.

The experimentations began with a few kilograms of ABS pellets he found at the market, with bags of red, blue, green, and white masterbatch pellets showing up at the Hackerspace. Experimenting with these pellets, [Rupin] was able to create some very nice looking filament that printed well and changed color over the course of a print.

There were a limitations of the process, though: the filastruder has a long melt zone, so colors will invariably mix. If you’re thinking about doing a red to blue transition with filament created on a Filastruder, you’ll end up with a filament with a little bit of red, a little bit of blue, and a lot of a weird purple color. The time to create this filament is also incredibly long; over the course of two days, [Rupin] was able to make about half a kilo of filament.

Still, the results look fantastic, and now that [Rupin] has a source for masterbatch and ABS pellets, he’s able to have a steady supply of custom color filament at the hackerspace.

Restarting 3D Prints

Image of a 3D print which was restarted using a different material

If a 3D printer is interrupted during a print, it will usually result in a junk part. Resuming the print can be very difficult. A group of researchers at MIT have built an add-on for 3D printers that uses a laser scanner to evaluate the state of the print, and allows the printer to restart.

While this will allow you to salvage some partially competed prints, the interesting application is switching between materials. In the image above, the lower piece was printed in ABS. The print was interrupted to change materials, and the top cube was printed in PLA. This allows for prints to mix materials and colors.

The add-on was tested with the Solidoodle 3D printer, and can be built for about $60. It requires a laser mounted to the print head, and a low-cost webcam for performing the measurements. While the group will not be continuing work on this project, they plan to open source their work so others can continue where they’ve left off.

After the break, we have a video of the printer performing a scan and resuming a print.

Continue reading “Restarting 3D Prints”

Developed on Hackaday: We Have Final Prototypes!

The last few weeks have been quite tense for the Mooltipass team as we were impatiently waiting for our smart cards, cases and front panels to come back from production. Today we received a package from China, so we knew it was the hour of truth. Follow us after the break if you have a good internet connection and want to see more pictures of the final product

Mooltipass final prototype

Continue reading “Developed on Hackaday: We Have Final Prototypes!”