3D Print For Extreme Temperatures (But Only If You’re NASA)

April 25, 2023 by Jenny List 23 Comments

At the level pursued by many Hackaday readers, the advent of affordable 3D printing has revolutionised prototyping, as long as the resolution of a desktop printer is adequate and the part can be made in a thermoplastic or resin, it can be in your hands without too long a wait. The same has happened at a much higher level, but for those with extremely deep pockets it extends into exotic high-performance materials which owners of a desktop FDM machine can only dream of.

NASA for example are reporting their new 3D printable nickel-cobalt-chromium alloy that can produce extra-durable laser-sintered metal parts that van withstand up to 2000 Fahrenheit, or 1033 Celcius for non-Americans. This has obvious applications for an organisation producing spacecraft, so naturally they are excited about it.

The alloy receives some of its properties because of its oxide-dispersion-strengthened composition, in which grains of metal oxide are dispersed among its structure. We’re not metallurgists here at Hackaday, but we understand that the inconsistencies in the layers of metal atoms caused by the oxides in the crystal structure of the alloy leads to a higher energy required for the structure to shear.

While these particular materials might never be affordable for us mere mortals to play with, NASA’s did previously look into how it could greatly reduce the cost of high-temperature 3D printing by modifying an existing open source machine.

Testing Part Stiffness? No Need To Re-invent The Bending Rig

April 24, 2023 by Donald Papp 3 Comments

If one is serious about testing the stiffness of materials or parts, there’s nothing quite like doing your own tests. And thanks to [JanTec]’s 3-Point Bending Test rig, there’s no need to reinvent the wheel should one wish to do so.

The dial caliper can be mounted to a fixed height, thanks to a section of 3030 T-slot extrusion.

Some simple hardware, a couple spare pieces of 3030 T-slot extrusion, a few 3D-printed parts, and a dial indicator all come together to create a handy rig that will let one get straight to measuring.

Here is how it works: stiffness of a material is measured by placing a sample between two points and applying a known force to the middle of the sample. This will cause the material to bend, and measuring how far a standardized sample deforms under a known amount of force (normally accomplished by a dial indicator) is how one can quantify a material’s stiffness.

When a material talks about its Young’s modulus (E) value, it’s talking about stiffness. A low Young’s modulus means a material is more elastic, a high value means the material is more stiff. (This shouldn’t be confused with strength or toughness, which are more about resistance to non-recoverable deformation, and resistance to fracture, respectively.)

Interested in results, but don’t want to get busy doing your own testing? Someone’s already been there and done that: here’s a great roundup of measurements of 3D-printed parts, using different filaments.

Using STEP And STL Files In FreeCAD

April 16, 2023 by Al Williams 11 Comments

If you’ve tried FreeCAD, you know that it has a daunting number of workbenches and options. [MangoJelly] has a large number of video tutorials on FreeCAD, and the latest one, below, covers working with STEP and STL with the tool.

If you’ve ever wondered why designers like to work with STEP files and not STL, this video answers that question immediately. A part brought in from a STEP file is closer to the original CAD object. It doesn’t have all the operations that make the part up, but it does have proper faces that you can work with like a normal part. The same part imported from STL, however, is one single mesh.

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3D-Printable Foaming Nozzle Shows How They Work

April 16, 2023 by Donald Papp 8 Comments

[Jack]’s design for a 3D-printable foaming nozzle works by mixing air with a fluid like liquid soap or hand sanitizer. This mixture gets forced through what looks like layers of fine-mesh sieve and eventually out the end by squeezing the bottle. The nozzle has no moving parts but does have an interesting structure to make this possible.

The fine meshes are formed by multiple layers of bridged filament.

Creating a foam with liquid soap requires roughly one part soap to nine parts air. The idea is that the resulting foam makes more efficient use of the liquid soap compared to dispensing an un-lathered goop directly onto one’s hands.

The really neat part is that the fine mesh structure inside the nozzle is created by having the printer stretch multiple layers of filament across the open span on the inside of the model. This is a technique similar to that used for creating bristles on 3D-printed brushes.

While this sort of thing may require a bit of expert tweaking to get the best results, it really showcases the way the fundamentals of how filament printers work. Once one knows the process, it can be exploited to get results that would be impossible elsewhere. Here are a few more examples of that: printing only a wall’s infill to allow airflow, manipulating “vase mode” to create volumes with structural ribs, and embedding a fine fabric mesh (like tulle) as either a fan filter or wearable and flexible armor. Everything’s got edge cases, and clever people can do some pretty neat things with them (when access isn’t restricted, that is.)

3D Printed Tool Lets You Measure Component Reels Easily

April 15, 2023 by Lewin Day 5 Comments

Component reels are a highly-0ptimized packaging format. They deliver components to pick and place machines for effective high-speed assembly. As more of us get into working with SMD components, we’re exposed to them as well. [MG] wanted a way to easily measure tape from component reels, which is difficult because they’re often curled up. Thus, they whipped up a nifty little tool for the job.

The device consists of a 3D printed bracket which is designed to fit on a cheap electronic tape measure from Amazon. The bracket holds an 8mm wide component tape against the measuring wheel. As the component tape is fed through the device, it turns the wheel, and the measurement appears on the screen. No more must you try and flatten out a tape and measure it section by section. Instead, you just feed it in, yank it through, and you’re done!

[MG] notes that the tape measure itself runs on an STM32 microcontroller. As an extra-credit assignment, they suggest that the device could be reprogrammed to display component count instead of distance if that’s more suitable for your application. If you happen to make that mod, be sure to notify us on the tipline!

3D Printed Artificial Nose Is Totally Vegan

April 14, 2023 by Lewin Day 13 Comments

Prosthetics are complicated, highly personal things. They must often be crafted and customized precisely to suit the individual. Additive manufacturing is proving a useful tool in this arena, as demonstrated by a new 3D printed nose design developed at Swansea University. And a bonus? It’s vegan, too!

Often, cartilage from the ribcage is used when reconstructing a patient’s nose. However, this procedure is invasive and can lead to health complications. Instead, a nanocellulose hydrogel made from pulped softwood, combined with hyaluronic acid, may be a viable printable material for creating a scaffold for cartilage cells. The patients own cartilage cells can be used to populate the scaffold, essentially growing a new nose structure from scratch. The technique won’t just be limited to nose reconstructions, either. It could also help to recreate other cartilage-based structures, such as the ear.

As with all new medical technologies, the road ahead is long. Prime concerns involve whether the material is properly bio-compatible, particularly where the immune system is concerned. However, the basic idea is one that’s being pursued in earnest by researchers around the world, whether for cosmetic purposes or to grow entire organs. As always, if you’re secretly 3D printing functional gallbladders in your basement, don’t hesitate to drop us a line.

Dual Extrusion Support Without PVA

April 12, 2023 by Al Williams 5 Comments

If you have an FDM printer that features multiple hotends or can otherwise switch between different filaments, you’ve surely thought about using the capability to lay down dedicated support material. Historically the filament of choice for this is PVA, since it can be dissolved in water once the print has finished. But if you’ve ever used it, you’ll know it’s not without its own challenges. Luckily, there may be an alternative — [ModBot] had heard that it is possible to use PLA to support PETG and vice-versa so he decided to try it. You can see how it works in the video below.

Of course, you can simply use PLA to support PLA and PETG to support PETG. Depending on the supports and slicer settings, though, it can be hard to remove the support after printing cleanly. Slicers have made major improvements in this area, but it still isn’t ideal. Some use HIPS for support, but that requires a solvent to dissolve and is also a bit exotic compared to PLA and PETG.

To illustrate, [ModBot] printed some test articles with the alternate support and did more reference prints using the same material with different parameters. The typical gap slicers use is 0.2 mm, but when using the different materials you can set the gap to zero. For the reference parts he set the gap to zero and 0.1 mm, both closer than you would normally print.

The PLA-only prints were essentially impossible to separate. While the PETG prints separated with tools, the resulting surfaces were ugly, with support residue and scarring. But the prints with two materials and zero gap pulled apart readily with no tools and left a beautiful surface underneath.

If you have the ability to do dual extrusion, this could be a great trick to have in your toolbox. Granted, PVA will still be of interest if you have support buried deep inside some structure where it is physically difficult to get to. Water can go where tweezers can’t. But for supporting large accessible areas, this looks like a game-changer.

Sometimes automatic supports can use a little help. There are plenty of supports and best practices for supports if you want to fine-tune your process.

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