Show HN: 3D print Z reinforcement via injected loops

Show HN: 3D print Z reinforcement via injected loops(mgunlogson.github.io)

26 points by mgunlogson 5 days ago | 8 comments

Commodity FDM print strength is limited by poor Z-axis layer bonding. Parts crack along Z under stress. MAGMA tries to fix this in software that works on any FDM 3D printer.

It's a fork of OrcaSlicer with a new infill type that creates paired U-shaped vertical channels inside the print, plus G-code that injects molten plastic into those channels to bridge Z layer interfaces with continuous plastic.

Big caveat: I have a junky Ender 3 and haven't gotten a clean physical print yet. Don't expect this to work out of the box! After months of tinkering, I'm releasing the software so the 3DP community can experiment with nozzles, multi-material, weird hardware, and other print parameters I can't. There's around 40 MAGMA-specific settings to fiddle with, plus some general quality-of-life features (e.g. printing thin infill sections as solid, and a "dual infill shell" feature that applies MAGMA only to the outer shell to save print time).

THIS CODE IS ALPHA. Around 50 prints old. The injection G-code is novel. Some printer firmware won't like extruding without movement. In extreme cases it could damage your printer or start a fire. DON'T WALK AWAY WHILE PRINTING.

Why MAGMA? "Lava tubes" is a misnomer. Molten rock is magma underground, lava only after it surfaces. The injected tubes are buried inside the print, so "magma tubes" is the correct term.

slabity 1 hour ago |

I've seen this technique a lot, but mostly as a post-processing technique where resin, fiber, or some other type of plastic is injected into the channels after printing is completed. It would be interesting to see this done during the normal printing process.

I am a little skeptical on the technique though. FDM printed walls are known to not handle pressure well, especially during printing when its past its glass-transition temperature. This process essentially uses the pressure from the extruder to inject a channel with molten plastic. Will this pressure could cause the walls to delaminate from each other or deform?

And how does this affect plastic that tends to warp significantly during printing? The molten plastic is injected into insulated channels that will not receive any active cooling. You're also parking the nozzle at the injection points, which will cause a lot of uneven cooling at the surface as well. For high-warping plastics like ABS, that could cause a lot of issues.

So I guess the underlying question should be, does this actually work? What is the measured difference in tension strength between parts printed normally vs with MAGMA infills? Specifically when using the same amount of plastic. There's no data or even pictures that indicate this is working.

rao-v 37 minutes ago | |

I think the way this works is with an internal structure, that houses the plastic and is expected to deform, printed first (so it cools), then outer walls with perhaps some air gaping for insulation, then injection into the inner structure at the lowest temp possible, then the next level starts.

Would print slow but might be genuinely strong vs normal infill + many walls (weight for weight).

Multi head printers like the U1 or H2D could do even better with high heat deflection temp plastics like carbon ASA or nylon for the inner structure and outer walls and strong low temp PLA for the injection.

deckar01 59 minutes ago |

When you say continuous interlocking U shape, are you saying it fills one channel from the top until the connected channel fills from the bottom?

dwallin 2 hours ago |

Instead of one large channel throughout the whole print, why not multiple small 2-4 layer bridges?

gus_massa 4 days ago |

Do you have a photos of objects you build with this? A video?

mgunlogson 4 hours ago | |

No, unfortunately. I've printed a ton of objects but nothing clean enough to be interesting.

The top of cells always melt as I'm using the same material for injection and the rest of the print. Someone with a dual nozzle printer could try something like PLA injection in a polycarbonate part. I added support but don't have a printer capable of that.

It's also possible that different print settings would work. I'm releasing the features to the community as I've run out of patience with doing a hundred hours of test prints.

We need to crowd test the best settings and nozzles, materials, etc to make this work well

coryrc 2 hours ago |

Why do you think this is better than the old practice of filling straight holes a few layers deep?

mgunlogson 5 days ago |

Here for any questions about how it all works :).