For general everyday use, there’s nothing wrong with the standard selection of plastics that most 3D printer filaments are available in. PLA, ABS, PETG — they’ve all got their place, and they’re all pretty easy to work with. But if you need to work with more exotic materials, you might need to go to extremes and modify an off-the-shelf printer for high-temperature work.
For the team led by [Andreas Hagerup Birkelid] at the Norwegian University of Science and Technology, the standard menu of printer chow wasn’t up to the jobs they had in mind. They wanted to print using polyether ether ketone, or PEEK, a high-performance thermoplastic with useful mechanical and thermal properties, in addition to chemical resistance. Trouble is, the melting point of PEEK is a whopping 343°C (649°F), making it necessary to turn up the heat — a lot. A standard Creality CR-10 printer was upgraded to withstand not only the 500°C max temperature of the new hot end and 200° printed bed, but also to survive operating in what amounts to an oven — a balmy 135° in a chamber made from IKEA cabinets. That entailed replacing plastic parts with metal ones, upgrading belts, pulleys, and wires, and moving all the electronics outside the enclosure. Even the steppers got special treatment, with water cooling to keep their magnets from reaching the Curie point.
The mods seemed to do the trick, because a Benchy printed in a carbon-fiber PEEK filament came out pretty good. It seems like a long way to go and kind of pricey — $1,700 for the printer and all the mods — but if you have a need to print exotic materials, it’s way cheaper than a commercial high-temp printer.
Despite the impressive variety of thermoplastics that can be printed on consumer-level desktop 3D printers, the most commonly used filament is polylactic acid (PLA). That’s because it’s not only the cheapest material available, but also the easiest to work with. PLA can be extruded at temperatures as low as 180 °C, and it’s possible to get good results even without a heated bed. The downside is that objects printed in PLA tend to be somewhat brittle and have a low heat tolerance. It’s a fine plastic for prototyping and light duty projects, but it won’t take long for many users to outgrow its capabilities.
The next step up is usually polyethylene terephthalate glycol (PETG). This material isn’t much more difficult to work with than PLA, but is more durable, can handle higher temperatures, and in general is better suited for mechanical parts. If you need greater durability or higher heat tolerance than PETG offers, you could move on to something like acrylonitrile butadiene styrene (ABS), polycarbonate (PC), or nylon. But this is where things start to get tricky. Not only are the extrusion temperatures of these materials greater than 250 °C, but an enclosed print chamber is generally recommended for best results. That puts them on the upper end of what the hobbyist community is generally capable of working with.
But high-end industrial 3D printers can use even stronger plastics such as polyetherimide (PEI) or members of the polyaryletherketone family (PAEK, PEEK, PEKK). Parts made from these materials are especially desirable for aerospace applications, as they can replace metal components while being substantially lighter.
These plastics must be extruded at temperatures approaching 400 °C, and a sealed build chamber kept at >100 °C for the duration of the print is an absolute necessity. The purchase price for a commercial printer with these capabilities is in the tens of thousands even on the low end, with some models priced well into the six figure range.
Of course there was a time, not quite so long ago, where the same could have been said of 3D printers in general. Machines that were once the sole domain of exceptionally well funded R&D labs now sit on the workbenches of hackers and makers all over the world. While it’s hard to say if we’ll see the same race to the bottom for high temperature 3D printers, the first steps towards democratizing the technology are already being made.
It seems as though every week we see something that clearly shows we’re living in the future. The components we routinely incorporate into our projects would have seemed like science fiction only a few short years ago, but now we buy them online and have them shipped to us for pennies. And what can say we’ve arrived in the future more than off-the-shelf plasma thrusters for the DIY microsatellite market?
Although [Michael Bretti] does tell us that he plans to sell these thrusters eventually, they’re not quite ready for the market yet. The AIS-gPPT3-1C series that’s currently under testing is designed for the micro-est of satellites, the PocketQube, a format with a unit size only 5 cm on a side – an eighth the size of a 1U CubeSat. The thrusters are solid-fueled, with blocks of Teflon, PEEK, or Ultem that are ablated by a stream of plasma. The gaseous exhaust is accelerated and shaped by a magnetic nozzle that’s integrated right into the thruster. The thruster is mounted directly to a PCB containing the high-voltage supplies and control electronics to interface with the PocketQube’s systems. The 34-gram thrusters have enough fuel for perhaps 500 firings, although that and the specifics of performance are yet to be tested.
We’ve seen FDM printers lay down layers by extruding plastic in a line. We’ve seen printers use sintering and lithography to melt or cure one layer at a time before more print medium moves into place for the next layer. What we’ve never seen before is a printer like this that builds parts from distinct layers of substrate.
At the International Manufacturing Technology Show last week I spoke with Eric of Impossible Objects. The company is using a “sheet lamination process” that first prints each layer on carbon fiber or fiberglass, then uses a hydraulic press and an oven to bake the part into existence before bead-blasting the excess substrate away. Check out my interview with Eric and join me below for more pictures and details.
There are dozens of different 3D printable cases out there for the Raspberry Pi, but the BeagleBone Black, as useful as it is, doesn’t have as many options. The folks at 3D hubs thought they could solve this with a portable electronics lab for the BBB. It opens like a book, fits a half-size breadboard inside, and looks very cool.
There’s a box somewhere in your attic, basement, or garage filled with IDE cables. Wouldn’t they be useful for projects? Yep, only not all the wires work; some are grounds tied together, some are not wired straight through, and some are missing. [esot.eric] has the definitive guide for 80-wire IDE cables.
If you have a 3D printer, you’re probably familiar with PEEK. It’s the plastic used as a thermal break in non-all-metal hotends. Now it’s a filament. An extraordinarily expensive filament at €900 per kilogram. Printing temperature is 370°C, so you’ll need an all-metal hotend.
It’s the Kickstarter that just keeps going and going and going. That’s not a bad thing, though: there really isn’t much of a market for new Amiga 1200 cases. We’ve featured this project before, but the last time was unsuccessful. Now, with seven days left and just over $14k to go, it might make it this time.
[morcheeba], who you should remember from CVS camera hacking, picked up a Peek and took some pictures while tearing it down. The Peek is a $100 QWERTY device with a simple OS designed only to check email. The device is being sold by T-Mobile with a $19.95/mo data plan. There’s nothing too spectacular to see other than 16MB of flash memory and a TI OMAP processor.