Bringing High Temperature 3D Printing To The Masses

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.

Industrial 3D printers like the Apium P220 start at $30,000.

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.

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Is Baking A Raspberry Pi The Recipe For Magic Smoke?

No, Hackaday hasn’t become a baking blog. We’re just here to give you a bit of advice: if [MickMake] ever offers you one of his fresh-baked Pis, proceed with caution. While we have no doubt that there will be some interesting smells wafting out of his kitchen, these aren’t the tasty pies you’re looking for. There’s no delicious home-baked treat when that timer dings, just a handful of Raspberry Pis that have had an exceptionally hard day.

To properly explain the odd sight of some Raspberry Pis laid out on a cookie sheet, we need to take a step back. [MickMake] originally set out to see how everyone’s favorite Linux SBC would handle the harsh Australian heat, and thought that setting them up on his car’s dashboard would be a suitable torture test. But as luck would have it, a storm rolled in while he was making the video which brought temperatures down to a “cool” 30 C (86 F); basically jacket weather at the bottom of the world. So naturally, he decided to put them in his oven instead.

Placed on an insulating sheet and with a thermocouple between them to get an accurate idea of the temperature they were experiencing, an original Pi, a Pi 2, and a pair of Pi 3s were sent on the ride of their lives. In addition to monitoring them over the network, he also added a “heartbeat” LED to each Pi so he’d be able to tell at a glance if any of them had given up the ghost. As if these poor little Pis didn’t have it bad enough already, [MickMake] decided to take things a step farther and run sysbench on them while they took their trip through Hades.

The Pis are actually rated for temperatures up to 85C, and all the participants of the experiment hit that point without any issues. At 87.3 C (~190 F) the original Pi dropped off the network, but its LED was seen bravely blinking on. At 105.7 C (~222 F) it finally breathed its last, followed by the pair of Pi 3s tapping out at 112 C (233 F). The Pi 2 fought on, but it fell right at the 119 C (246 F) mark.

But what about when they cooled off? Somewhat surprisingly, [MickMake] successfully powered all four back up and was unable to find any damage to the Pis, either physically or operationally. Even the SD cards survived, and the Pis popped right back onto the network and were ready for another round of Silicon Chef. Not bad considering they were subjected to temperatures three times higher than the official limit.

Testing electronics in your home oven might seem a bit suspect, and admittedly we’d probably turn down a slice of the next few frozen pizza’s [MickMake] runs through it, but it’s not really so far removed from how proper reliability testing is performed.

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Digital Kiln

A kiln or foundry is too often seen as a piece of equipment which is only available if a hackspace is lucky enough to have one or individuals are dedicated enough to drop the cash for one of their own. [The Thought Emporium] thought that way until he sourced materials to make his own kiln which can also be seen after the break. It costs half the price of a commercial model not including a failed—and exploded—paint can version.

As described in the video, these furnaces are tools capable of more than just pottery and soft metal baubles. Sure, a clay chess set would be cool but what about carbon fiber, graphene, aerogel, and glass? Some pretty hot science happens at high temperatures.

We get a nice walk-through of each part of the furnace starting with the container, an eleven-gallon metal tub which should set the bar for the level of kiln being built. Some of the hardware arrangements could be tweaked for safety and we insist that any current-carrying screw is safely mounted inside an enclosure which can’t be opened without tools. There’s good advice about grounding the container if metal is used. The explanation of PID loops can be ignored.

What else can you do with a kiln? How about jewelry, heat treating metal, or recycle your beer cans into an engine.

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