A man’s hands are shown in the foreground holding two splines, each with teeth both on the interior and exterior surfaces. Both are identical in shape, but one is larger and made of plastic, and the other is smaller and made of metal.

Freeze-drying For Improved Metal Printing

June 6, 2025 by Aaron Beckendorf 12 Comments

For all the remarkable improvements we’ve seen in desktop 3D printers, metal printers have tended to stay out of reach for hackers, mostly because they usually rely on precise and expensive laser systems. This makes it all the more refreshing to see [Dan Gelbart]’s demonstration of Rapidia’s cast-to-sinter method, which goes from SLA prints to ceramic or metal models.

The process began by printing the model in resin, scaled up by 19% to account for shrinkage. [Dan] then used the resin print to make a mold out of silicone rubber, after first painting the model to keep chemicals from the resin from inhibiting the silicone’s polymerization. Once the silicone had set, he cut the original model out of the mold and prepared the mold for pouring. He made a slurry out of metal powder and a water-based binder and poured this into the mold, then froze the mold and its contents at -40 ℃. The resulting mixture of metal powder and ice forms a composite much stronger than pure ice, from which [Dan] was able to forcefully peel back the silicone mold without damaging the part. Next, the still-frozen part was freeze-dried for twenty hours, then finally treated in a vacuum sintering oven for twelve hours to make the final part. The video below the break shows the process. Continue reading “Freeze-drying For Improved Metal Printing” →

First Benchies In Stainless Steel, With Lasers

October 7, 2024 by Elliot Williams 19 Comments

DIY 3D printing in metal is a lot more complicated than we thought. And this video from [Metal Matters] shows two approaches, many many false starts, and finally, a glorious 78.9% success! (And it’s embedded below for your enjoyment.)

The first half of the video is dedicated to the work on a laser welding system that doesn’t pan out in the end at all. But the missteps are worth watching as well, and they hammer home the difficulties of melting metal reliably with nothing more than coherent light. Things like reflection, the difficulty of getting good process control cameras, and finally the whole thing slumping as multiple layers stack up on each other make this approach to 3D construction look nearly impossible.

Indeed, around halfway through the video, the focus shifts toward a metal-powder sintering machine, and this one is a success! Metal dust is deposited layer by layer, and fused with a totally different laser. The tricky bits here range from esoteric problems like making the laser fuse the metal dust without blasting it, to simple things like the geometry of the scraper that ensures even layer heights. And once you’ve got all that down, getting a good pattern down for 2D infill in metal is non-trivial.

A sweet half-scale metal Benchy emerges at the end, so why does [Metal Matters] call this a 78.9% success? Because that’s the density of the final print, and he is shooting for 100%. But we wouldn’t be so harsh. We’ve seen how far he’s come since the first machines, and this is a huge advance. We’re looking forward to the next video update in a year or two!

Continue reading “First Benchies In Stainless Steel, With Lasers” →

New Additive Manufacturing Contenders: HIP And Centrifugal Printing

July 20, 2024 by Maya Posch 6 Comments

Additive Manufacturing (AM) is a field of ever-growing importance, with many startups and existing companies seeking to either improve on existing AM technologies or market new approaches. At the RAPID + TCT 2024 tradeshow it seems that we got two more new AM approaches to keep an eye on to see how they develop. These are powder-based Hot Isostatic Pressing (HIP) by Grid Logic and centrifugal 3D printing by Fugo Precision.

Grid Logic demo at RAPID + TCT 2024. (Credit: Ian Wright)

Grid Logic’s HIP uses binder-less powders in sealed containers that are compressed and deposited into a HIP can according to the design being printed, followed by the HIP process. This is a common post-processing step outside of AM as well, but here HIP is used as the primary method in what seems like a budget version of typical powder sintering AM printers. Doubtlessly it won’t be ‘hobbyist cheap’, but it promises to allow for printing ceramic and metal parts with minimal wasted powder, which is a major concern with current powder-based sintering printers.

While Grid Logic’s approach is relatively conservative, Fugo’s Model A printer using centrifugal printing is definitely trying to distinguish itself. It uses 20 lasers which are claimed to achieve 30 µm accuracy in all directions with a speed of 1 mm/minute. It competes with SLA printers, which also means that it works with photopolymers, but rather than messing with FEP film and pesky Earth gravity, it uses a spinning drum to create its own gravitational parameters, along with a built-in parts cleaning and curing system. They claim that this method requires 50% fewer supports while printing much faster than competing commercial SLA printers.

Even if not immediately relevant to AM enthusiasts, it’s good to see new ideas being tried in the hope that they will make AM better for all of us.

Mining And Refining: Tungsten

April 2, 2024 by Dan Maloney 16 Comments

Our metallurgical history is a little bit like a game of Rock, Paper, Scissors, only without the paper; we’re always looking for something hard enough to cut whatever the current hardest metal is. We started with copper, the first metal to be mined and refined. But then we needed something to cut copper, so we ended up with alloys like bronze, which demanded harder metals like iron, and eventually this arms race of cutting led us to steel, the king of metals.

But even a king needs someone to keep him in check, and while steel can be used to make tools hard enough to cut itself, there’s something even better for the job: tungsten, or more specifically tungsten carbide. We produced almost 120,000 tonnes of tungsten in 2022, much of which was directed to the manufacture of tungsten carbide tooling. Tungsten has the highest melting point known, 3,422 °C, and is an extremely dense, hard, and tough metal. Its properties make it an indispensible industrial metal, and it’s next up in our “Mining and Refining” series.

Continue reading “Mining And Refining: Tungsten” →

3D Print Glass With A Laser Cutter

May 28, 2022 by Jenny List 15 Comments

We’re all familiar with FDM 3D printing, and some of the more well-heeled or adventurous among us may even have taken a faltering step into the world of SLA printers. But for most of us there’s a step further in 3D printing that remains beyond our reach. SLS, or Selective Laser Sintering, creates prints from powder by melting it layer by layer using a laser, and has the advantage of opening up more useful materials than the polymer stock of the other methods. It’s not entirely unreachable though, as [Kenneth Hawthorn] shows us by using a laser cutter to produce SLS prints from powdered glass.

He evolved the technique of repeated fast passes with the laser to gradually melt more glass together as opposed to slower passes. He achieved a resolution as low as 0.1 mm, though he found a better glass color when the laser was less tightly focused. It raises the concern that glass powder is abrasive and thus a threat to any mechanism, thus he’s being extremely careful with the fan settings.

This may not be quite in the league of an SLS printer costing thousands of dollars, but it’s a technique that bears more investigation and could no doubt be refined for more custom fused glass creations. He tells us he was inspired by a previous Hackaday post about sintering sand, and of course we’d like to remind readers of a 3D printer that did the same job with the power of the sun.

3D Printed Copper Rocket Nozzle Costs Under Two Grand

July 9, 2021 by Al Williams 19 Comments

You don’t think of hobby-grade 3D printing as a good method for creating rocket nozzles. But [Mister Highball] managed to create a copper nozzle using a common printer, a kiln, and some special copper-bearing filament.

The copper filament is about 90% metal. Virtual Foundry recommends preheating it before printing and you have to sinter it in an oven to remove the plastic and leave a solid metal piece which will, of course, shrink.

Continue reading “3D Printed Copper Rocket Nozzle Costs Under Two Grand” →

3D Printering: To Print Stainless, You Do Half The Work

February 25, 2021 by Al Williams 37 Comments

Everyone wants to print using metal. It is possible, but the machines to do the work are usually quite expensive. So it caught our eye when MakerBot announced a printer — armed with an experimental extruder — that can print stainless steel parts. Then we read a bit more and realized that it can only sort of do the job. It needs a lot of help. And with some reasonable, if not trivial, modifications, your printer can probably print metal as well.

The key part of the system is BASF Ultrafuse 316L Stainless Steel filament, something that’s been around for a few years. This is a polymer with metal incorporated into it. This explains the special extruder, since metal-bearing filament is hell on typical 3D printer nozzles. However, what comes out isn’t really steel — not yet. For that, you have to send the part to a post-processing facility where it is baked at 1380 °C in a pure hydrogen atmosphere using special equipment. This debinding and sintering produces a part that the company claims can be up to 96% pure metal.

Continue reading “3D Printering: To Print Stainless, You Do Half The Work” →