1 Topic by markm

  • markm
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Topic: Feasibility Question - Support Structure

I was trying to think of various ways to have easy to remove support and a thought crossed my mind.  What if the build platform were enclosed in a water tight box and the platform had a water proof seal to the platform?  Then a moisture sensor off the print head could detect water depth to prevent an overflow.  As the platform lowers, a warm saline solution is pumped in to provide support for overhangs. Once the bulls is done, the saline is pumped back out and the item can be removed. Typing from phone so I can't give a better description, but hopefully have explained enough to get the point across. 
What would be the limitations or considerations that might keep this from working?

2 Reply by MeshMoth

  • MeshMoth
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Re: Feasibility Question - Support Structure

I pretty sure this idea has a slim chance of working with this type of printer.
Let me list some reasons why in random order.

• Salt water is no good for electronics.
• Water is not strong enough to support abs, it will be just the same as using nothing.
• Liquid will cool the printed parts way too fast.
• Heating the liquid will use way too much time and energy if it needs to stay heated 24/7.
• There is probably no way to make a tank water tight and allow free motion of the print head.
• Building such a machine with all the pumps and sensors would probably cost more than its worth.
• I dont think people would be interested in that much time and money for R&D.
• There are much easier and feasable alternatives like water soluble filament using a second extruder head.

Anyway, its a unique idea, but probably not so effective with this technology.

3 Reply by helagak

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Re: Feasibility Question - Support Structure

Not to mention that the extruder runs at 200c and water boils at 100c which means the hot end would instantly boil any water it touches...
Does that seem very feasible but new ideas are always appreciated. smile

4 Reply by Charles_Xavier

  • Charles_Xavier
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Re: Feasibility Question - Support Structure

MeshMoth wrote:

• Water is not strong enough to support abs, it will be just the same as using nothing.

This is the only point I disagree with. The surface tension alone will be enough to hold up bridges and overhangs (up to a certain size).

Otherwise, yes, I think this is more trouble than it could ever be worth.

5 Reply by markm

  • markm
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Re: Feasibility Question - Support Structure

Thanks, guys.  It wasn't anything I was wanting to mess with myself, so I hadn't really given it a whole lot of thought.  I'd also thought of mineral oil instead of saline (going back to my days of OC'ing processors).  Not on my phone now, so I can actually get a bit more involved in the conversation, so I'll give some clarification/detail on what I was thinking.
The build platform would be similar to a hydraulic cylinder, without the pressure, and the liquid-proof box that surrounds it would be made like the walk-in bathtubs so the front could be opened to remove items.  My off-the-cuff thinking on it only required two pumps:  one for pumping the fluid into the platform and one for removal of fluid at end of printing.  It would also need the moisture sensor for shutting off with each step.  Beyond that, it'd just require controlling the pump to turn on when the Z-axis changes.
The big issue I thought of was that the platform would have to be belt-driven from underneath, requiring the printer to be at least twice as tall as the build height, to allow for movement.  Mineral oil would also take away the possibility of boiling, since the boiling point for it (if I remember correctly) is over 260C. 

Like I said, I appreciate the input, and this was just a thought experiment for me, but if someone out there gets some inspiration from it in some fashion, then great.  If not, well, it's still fun to daydream of Rube Goldberg machines sometimes.