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slabitytoday at 5:10 PM1 replyview on HN

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.


Replies

rao-vtoday at 6:12 PM

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.