Microwave Sintering

I think we’ll call this “foreshadowing” I’ve only tackled it minimally. But enough to prove the concept with Bronze filament.

I did my initial testing with one of those microwave kilns people use for glass Link Here

Here’s a great in-depth article from a more commercial perspective, but all of the fundamentals apply to us. Microwave Sintering of Metals

Actually, just sintering this way has proven to be pretty simple and straight forward. Debinding in a microwave may not be practical. But even if you were to debind as a preliminary step, then sinter in a microwave, there are advantages to be had.

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Excited to see it :+1::+1:

It looks like those microwave oven kilns get hot enough to sinter bronze, at least, but is it safe to run a microwave for the full 16+ hr debind/sinter process?

As for debinding. I’m picturing a hybrid process for sintering in a microwave. One where you would debind in a separate step, then move the crucible to the microwave to sinter it.

Those microwave kilns use Silicon Carbide as an energy collector for the microwaves. We’re just finishing up a Silicon Carbide 3d printable filament. My vision (one of many) is that we either use one of these pre-made microwave kilns, or use a multi-material printer to place the microwave concentrators in just the right areas either within or around the print. Debinding is a separate problem, but sintering time could come down to just a few minutes rather than hours.

The microwave heating part of this equation is well researched: Google Search Here

Definitely would need to be an abbreviated cycle IMO for complete debinding/sintering in a microwave. Maybe like, 1 hour to get up to temperature for debinding and another one for sintering. Or as brad says, debind separately using heat or chemistry first then sinter. The actual sintering is pretty fast once it gets up to temperature with my main concern getting heat distributed evenly everywhere in that short amount of time…

The benefits of being able to print metal using a microwave are just too big to pass up for me not to at least explore it though!

Hello VF fans :slight_smile:
Thanks for accepting me in the group !
This topic is super exciting Brad !!
It happened that i also tested the microwave sintering for Aluminium filamet before.
I was not sure i could reach temperatures high enough for copper or bronze so the test start was with the aluminium.
The process works somehow
but is super difficult to master i would say.
It is very difficult to keep a temperature stable and reach a desired one as the magnetron ON/OFF often. Enclosed picture shows the result with aluminium ( was trying to make an aluminium profile :smile: ). As you can see the aluminium melts and cools down too quickly (?) and it ends up gathering and forming aluminium bubbles.
if anyone can help :slight_smile:

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Silicon Carbide 3d printable filament is a great idea ! :slight_smile:

You’re the first person I’ve met who has been printing with aluminum!

On the one hand… yes, it’s the lowest temperature metal offered. On the other hand, aluminum is notoriously difficult to sinter because it has a passive oxide layer. And it’s reactive too. I’d be very impressed if you managed to get it though!

I would think glass (or ceramic) might be the easiest, because then you don’t have to worry about oxygen at all. There is also a much more relaxed temperature range (from 850 C all the way up to 1300+) where sintering occurs but with increasing densification, unlike with say copper where a 4 degree temperature change in my oven changes things like crazy.