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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Improved Flexible Build Plate For SLA Is Ready To Rock

The Elegoo Mars is an affordable SLA (resin-based) 3D printer, and there are probably few that have seen more mods and experimentation than [Jan Mrázek]’s machine. The final design of his DIY flexible build plate is a refinement of his original proof of concept, which proved a flexible build platform can be every bit as useful on an SLA printer as it is for FDM; instead of chiseling parts off a rigid build platform, simply pop the flexible steel sheet off the magnetic base and flex it slightly for a much easier part removal process. His original design worked, but had a few rough edges that have since been ironed out.

[Jan]’s magnetic build platform.
We love how [Jan] walks through all of the design elements and explains what worked and what didn’t. For example, originally he used a galvanized steel sheet which was easy enough to work with, but ended up not being a viable choice because once it’s bent, it stays bent. Spring steel is a much better material for a flexible build platform, but is harder for a hobbyist to cut.

Fortunately, it’s a simple job for any metal fabrication shop and [Jan] got a variety of thicknesses cut very cheaply. It turns out that the sweet spot is 0.3 mm (although 0.2 mm is a better choice for particularly fragile parts.) [Jan] also suggests cutting the sheet a few millimeters larger than the build platform; it’s much easier to peel the sheet off the magnetic base when one can get a fingertip under an edge, after all.

The magnetic base that the steel sheet sticks to is very simple: [Jan] converted a stock build platform by mounting an array of 20 x 20 x 1 mm magnets with 3M adhesive mounting tape. He was worried that resin might seep in between the magnets and cause a problem, perhaps even interfering with the adhesive; but so far it seems to be working very well. Resin is viscous enough that it never penetrates far into the gaps, and no effect on the adhesive has been observed so far.

Watch how easily parts are removed in the short video embedded below, in which [Jan] demonstrates his latest platform design.

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Polymer Networks Make Better 3D Prints

Biological machines such as human and animal bodies are quite incredible. Your body seamlessly incorporates materials as different as muscle, bone, and tendons into an integrated whole. Now Texas A&M researchers think they can imitate nature using polymer networks that have a tunable stiffness. As a bonus, similar to biological devices, the material spontaneously self-heals.

The trick relies on the Diels-Alder reaction which is a cycloaddition reaction of a conjugated diene to an alkene. Diels-Alder-based polymers or DAPs will bond together even when they have different physical characteristics and they undergo a reversible reaction to heat which offers shape-memory and healing capability.

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Robotic Worm Uses NinjaFlex Filament

If you think about building a moving machine, you probably will consider wheels or tracks or maybe even a prop to take you airborne. When [nwlauer] found an earthworm in the garden, it inspired a 3D-printed robot that employs peristaltic motion. You can see a video of it moving, below.

The robot uses pneumatics and soft plastic, and is apparently waterproof. Your printer’s feed path has to be pretty rigid to support flexible filament without jamming. There’s also some PVA filament and silicone tubing involved.

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Plaster Annealing 3D Prints For Strength

[Stefan] is always trying to make stronger 3D prints. Annealing can strengthen prints, but often at the expense of the part’s exact dimensions. His latest approach is to embed the prints in plaster and then anneal in an attempt to fuse the plastic together without changing its shape or size. Did it work? See for yourself in the video below.

He’s done a lot of work we’ve taken note of before where he measures the strength of parts after different post-processing steps. His test plastic parts used both PLA and PETG.

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3D-Printed Adapter Keeps Your Guitar In Tune And In Style

If you like building or upgrading guitars, you may have already learned the valuable lesson that the devil absolutely is in the detail when it comes to to replacement parts. Maybe you became aware that there are two types of Telecaster bridges right after you drilled the holes through the body and noticed things just didn’t quite fit. Or maybe you liked the looks of those vintage locking tuners and the vibe you associate with them, only to realize later that the “vintage” part also refers to the headstock, and the holes in your modern one are too big.

The latter case recently happened to [Michael Könings], so he did what everyone with a 3D printer would: make an adapter. Sure, you can also buy them, but where’s the fun in that? Plus, the solution is as simple as it sounds. [Michael] modelled an adaptor to bridge the gap between the headstock holes and the tuner shaft, but unlike the commercial counterpart that are mounted only on one side, his fills up the entire hole and fits the entire construct tightly together. For even more overall stability, he added an interlocking mechanism on the back side that keeps all the adaptors in line, and also allows for some possible distance differences.

[Michael] initially considered using wood filament for cosmetic reasons, but due to lack of the material went with simple white PLA instead. In the end, it doesn’t matter too much, as most of it hides under the new tuners’ metal covers anyway — and the small parts that are visible will serve as a great reminder of this lesson in guitar variety. Speaking of 3D printing and guitar variety, now that we reached the headstock, and have seen bodies for a while already (including bass), only 3D-printed guitar necks are missing. Well, we’ve had them on violins though, even with 6 strings, but they also don’t have to deal with frets and have a bit less tension going on.

Reforming 3D Prints With Salt And Heat

The biggest problem with fused deposition 3D prints is that while the layers should stick together, they aren’t the same as a solid piece of plastic you would get from, say, injection molding. You can anneal plastic using moderate heat, but it is likely to cause the part to deform or change size. [Free Spirit 1] has a solution for this. Using a powdered salt, the part is packed on the inside and out and put in an oven. The results in the video below look really impressive.

In addition to making the part look solid and — we assume — adding strength, the resulting prints are also water- and gas-tight which was the purpose of the effort. That alone would make the technique worthwhile.

The only thing we noticed is that the part has to have access to hold the salt. Anything not supported would be subject to deformation. However, the ground-up salt is so fine that it should be relatively easy to fill in most parts and, of course, print with 100% infill to avoid hollow internal areas.

[Free spirit 1] used a coffee grinder to get the salt powder, but apparently you can buy “flour salt.” We wondered if other powders might work well, too. Apparently, sand didn’t work out, perhaps because the salt dissolves out in water, so whatever you use, it should probably dissolve in something that won’t attack your plastic.

Annealing isn’t a new idea, and we’d love to see some objective tests on this new method.

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