A bed of metal powder is visible through a green-tinted window. A fused metal pattern, roughly square, is visible, with one corner glowing white and throwing up sparks.

Printing In Metal With DIY SLM

An accessible 3D printer for metals has been the holy grail of amateur printer builders since at least the beginning of the RepRap project, but as tends to be the case with holy grails, it’s proven stubbornly elusive. If you have the resources to build it, though, it’s possible to replicate the professional approach with a selective laser melting (SLM) printer, such as the one [Travis Mitchell] built (this is a playlist of nine videos, but if you want to see the final results, the last video is embedded below).

Most of the playlist shows the process of physically constructing the machine, with only the last two videos getting into testing. The heart of the printer is a 500 Watt fiber laser and a galvo scan head, which account for most of the cost of the final machine. The print chamber has to be purged of oxygen with shielding gas, so [Travis] minimized the volume to reduce the amount of argon needed. The scan head therefore isn’t located in the chamber, but shines down into it through a window in the chamber’s roof. A set of repurposed industrial servo motors raises and lowers the two pistons which form the build plate and powder dispenser, and another servo drives the recoater blade which smooths on another layer of metal powder after each layer.

As with any 3D printer, getting good first-layer adhesion proved troublesome, since too much power caused the powder to melt and clump together, and too little could result in incomplete fusion. Making sure the laser was in focus improved things significantly, though heat management and consequent warping remained a challenge. The recoater blade was originally made out of printed plastic, with a silicone cord along the edge. Scraping along hot fused metal in the early tests damaged it, so [Travis] replaced it with a stainless steel blade, which gave much more consistent performance. The final results looked extremely promising, though [Travis] notes that there is still room for redesign and improvement.

This printer joins the very few other DIY SLM machines we’ve seen, though there is an amazingly broad range of other creative ideas for homemade metal printers, from electrochemical printers to those that use precise powder placement.

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Metal 3D Printing — A Dose Of Reality

We have no doubt that hundreds of times a day a hacker is watching a 3D printer spew hot plastic and fantasizes about being able to print directly using metal. While metal printers are more common than ever, they are still out of reach for most people printing as a hobby. But as Mr. Spock once observed: “…you may find that having is not so pleasing a thing after all as wanting. It is not logical, but it is often true.” However, metal 3D printing has its own unique set of challenges. Texas A&M recently produced a short video explaining some of the design issues that you’ll encounter trying to make practical metal prints on an SLS (Selective Laser Melting) printer. You can see the video below.

The description says “It is more challenging to ‘metal 3D print’ a part than most people think. We’ve noticed the same even with plastic printers as friends will expect us to print the most outlandish things for them. What we like about this video is it helps to set expectations of the current state of the art so we’re not expecting far more than today’s metal printers can produce.

Among the features covered in the video are overhangs, which require supports. After removal, the surface is about like 80 grit sandpaper unless you perform further finishing. Just like plastic parts, warping and curling of large areas is a problem with metal. If you’ve ever been frustrated removing plastic support material, try having to ceramic grind metal supports off. They also use an EDM machine to cut especially tough supports, but it causes a lot of effort since it is likely to run through EDM wires and clog the filters.

We looked at recent advances in metal printing last year. We’ve seen homebrew machines that were little more than welders under computer control and we’ve seen plans by big players like HP to create metal prints, but at a steep price. Still, you can’t stop the march of 3D printing progress.

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NASA Is 3D Printing Rocket Engine Parts

In case you haven’t heard, NASA is building a new rocket – a replacement for the shuttle – that will eventually take crews again outside low Earth orbit. It’s called the Space Launch System and looks surprisingly similar to the Saturn V that took men to the moon. Manufacturing technology is light years ahead of what it was in the mid-60s, and this time around NASA is printing some rocket parts with selective laser melting.

Teams at the Marshall Space Flight center are melting metal powder together with lasers to produce parts for the new J-2X engine intended for use in the earth departure stage of the Space Launch System. While the 3d-printed parts haven’t seen a use in any live fire tests of the J-2X, the goal is to test these parts out later in the year and eventually have them man-rated, to carry astronauts to the moon, asteroids, or even Mars.

This isn’t the first time 3d printing has been used to make rocket engines. Earlier this year we saw [Rocket Moonlighting] build an entire rocket engine, powered by propane and NO2, using the same technology that NASA is using. [Moonlighting]’s engine is quite small, too small to lift itself off the ground, even. Still, it’s awesome to see 3D printing that will eventually take people into solar orbit.

3D Printed Lugs For Your Custom Bike

We haven’t heard much about 3D printing using stainless steel as the medium, but that’s exactly what’s going on with the lugs used to assemble this bicycle frame. They’re manufactured using LaserCusing, which is a brand name for parts produced using Selective Laser Melting. The video after the break gives you an overview of what it takes to clean up each of these parts.

The laser melts metal power to solidify areas needed in the final part. Just like the hobby printing we’ve seen on the RepRap or Makerbot there are structural supports necessary to complete the print job, and these need to be removed after the laser has done its work. This is where the majority of the labor comes in. You’ll see a ton of waste material pulled out of the cage-like lug, and we’re sure there’s no shortage of filing and polishing to finish up. But wow, what an interesting result. We just need to figure out if anyone has found a cost-effective way to hack together one of these metal-powder printers.

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