The March Toward A DIY Metal 3D Printer

[Hyna] has spent seven years working with electron microscopes and five years with 3D printers. Now the goal is to combine expertise from both realms into a metal 3D printer based on electron-beam melting (EBM). The concept is something of an all-in-one device that combines traits of an electron beam welder, an FDM 3D printer, and an electron microscope. While under high vacuum, an electron beam will be used to fuse metal (either a wire or a powder) to build up objects layer by layer. That end goal is still in the future, but [Hyna] has made significant progress on the vacuum chamber and the high voltage system.

The device is built around a structure made of 80/20 extruded aluminum framing. The main platform showcases an electron gun, encased within a glass jar that is further encased within a metal mesh to prevent the glass from spreading too far in the event of an implosion.

The design of the home-brewed high-voltage power supply involves an isolation transformer (designed to 60kV), using a half-bridge topology to prevent high leakage inductance. The transformer is connected to a buck converter for filament heating and a step up. The mains of the system are also connected to a voltage converter, which can be current-fed or voltage-fed to operate as either an electron beam welder or scanning electron microscope (SEM). During operation, the power supply connects to a 24V input and delivers the beam through a Wehnelt cylinder, an electrode opposite an anode that focuses and controls the electron beam. The entire system is currently being driven by an FPGA and STM32.

The vacuum enclosure itself is quite far along. [Hyna] milled a board with two outputs for a solid state relay (SSR) to a 230V pre-vacuum pump and a 230V pre-vacuum pump valve, two outputs for vent valves, and inputs from a Piranni gauge and a Cold Cathode Gauge, as well as a port for a TMP controller. After demoing the project at Maker Faire Prague, [Hyna] went back and milled a mold for a silicone gasket, a better vacuum seal for the electron beam.

While we’ve heard a lot about different metal 3D printing methods, this is the first time we’ve seen an EBM project outside of industry. And this may be the first to attempt to combine three separate uses for an HV electron beam into the same build.

20 thoughts on “The March Toward A DIY Metal 3D Printer

  1. This project seems like it could be used in a von neumann probe. Is there a website for those interested in the subject? Even a limited non reproducing dumb remote controlled probe could have applications in asteroid mining, or off planet solar cells.

  2. One of the immutable rules of hacking, anything that has to be built in a vacuum inside an olde timey bell jar inside of a wire cage is automatically an extra 10 cool points.

  3. Everything about this project just screams amazing at me. Really impressive! I would pay to sit down with the creator and just ask questions about it for hours.

    Really inspiring to see someone setting out at work on something this technical and ambitious with a solid skillset

  4. There’s an opportunity to make this into a universal metal recycler, by combining subtractive and additive manufacturing into a single machine. If an electro-discharge machine were added as a tool option, its swarf is fine metal powder, feedstock for e-beam. The venn diagram of materials that can be processed by EDM, EBM, and the electron microscope, is just one big circle, anything electrically conductive. Insert a scrap of metal, let EDM spark it off, settle out the swarf, drain the dielectric and run the vacuum, then e-beam the swarf back onto it, in some new configuration.

    Ben Fleming’s got a book on how to DIY an EDM, and it’s pretty good, except you’ll need to find replacements for all his RadioShack parts.

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