3D Printable Live Rock

Glasswalker · Apr 13, 2016

Hey everyone, so I came up with a cool idea/experiment I'd like to try. Thought I'd post about it here.

I've been heavily involved in the 3D Printing scene since it's inception pretty much. I've designed, built, and owned many 3D printers over the years, and these days I also operate a 3D Hub doing printing services for others.

Anyway, I thought:
"Live rock provides one main purpose: Being porous, in order to allow the most surface area possible for life to adhere to, and grow within, essentially a solid structured form of substrate. The bacterial cultures and life that grows within this "structure" then provides natural filtration (again due to surface area and water permeability)"

There are other benefits as well, such as calcium solids being dissolved into the tank, helping with water buffering and so on. But these depend on the specific type of rock for example. Not all rock is based on actual dead coral skeleton.

In addition I've heard a few anecdotal mentions that things like giant piles of PVC pipe, have become "live" and actually worked for filtration, as well as people making artificial rock from a "cement" of sorts, made from substrate.

This all led to the thought:
"Why can't I 3D Print a specially designed structure to serve as live rock?"

Since we already know ABS is relatively reef safe. And ABS plastic is commonly used in 3D Printing, there is no reason it shouldn't work

And 3D Printing allows for creation of complex internal structures that may actually be beneficial. Not to mention the ability to totally customize look and feel. And once the rock begins to grow/support much life, it won't look any different than "real" live rock.

So I quickly whipped up this "proof of concept" design:
http://www.thingiverse.com/thing:1488701

Which I've release on creative commons license. Which has the following features:

Textured surface to support life growing on it
Organic look/feel
Some tunnels/caves
fully hollow shell with internal structure
Internal Structure designed for maximum surface area but easy flow-through
Many "holes" in outer shell into internal structure to allow water flow-through and small life to get in/out
Texturing from printing process should further improve surface area/texture
Possibility due to the structure/skin to fill it with coarse substrate via the holes, which could further improve it's life sustaining and filtering abilities, not to mention add some natural calcium. (also might help weigh it down lol)

Here are some pics:

Right now this is far from "cheap", but it's meant to be a proof of concept. Right now it's about 20cm long, by 15cm wide, by 10cm tall. So it's a medium size rock. At this size it's about $10 - $20 worth of plastic to print it on a home printer in standard ABS. If using a printing service, it would likely cost more than that.

That said, this is not optimized. Until I've been able to test things like the size/density of the internal structure can be tweaked to find an optimal balance of material usage, and life-supporting capabilities.

So optimized this might get down to the $5 - $10 range, which could be comparible to dry rock in pricing.

The real question is how effective it is at supporting life, and natural filtration.

Right now my tank isn't even finished being built yet, so I am nowhere near being able to test this. Once I get my tank up and running, cycled, and stable, I will toss one of these into the tank to see if I can turn it "live" and how it looks... Then maybe using a QT tank or something, we can try and test it's filtering capabilities.

But if anyone else is interested in testing this out, I'd love to see how it comes together. The file is free to download and try out, and if anyone's interested I'd be willing to print one of these out for you for just my cost in plastic, and shipping. Ideal situation is someone with a mature reef, and skills, and their own 3D Printer

My first test may also experiment with size a bit to see how small the internal structure can get and still print reliably. That can help me tweak the file for more efficient printing at larger sizes.

Anyway, any comments, feedback would be welcome. I'm interested to hear what anyone else thinks of this little experiment.

PurpleMonster · Apr 13, 2016

Very cool! Funny thing is i just started a thread so we can do just this.... Share our designs, simple and complex like yours!

reefwiser · Apr 13, 2016

Lets see is the inside of the "rock" honeycomb as it looks Things I would add is would be holes for frag plugs. Though I have found there is not a standard size in the shaft part of the frag plugs.

Should be ok like giant bio balls.

Glasswalker · Apr 13, 2016

I'll see if I can get a render of the skeleton without the skin to show better what the inside looks like. It's basically like the surface pattern but a giant mishmash of "web". Problem with standard honeycomb is that it only allows flow in one axis, so this method provides flow/permeability in all directions, while still supporting the part.

dorky · Apr 13, 2016

That sound kinda awesome!

kireek · Apr 13, 2016

I like the 3rd and the 5th example.The biggest drawback I could imagine would be the lack of buffering capabilities.I like your more natural looking holes for frags.It would be cool to see in colors if possible.In addition,I would be interested in how well you could cut or break it apart if you had to.

revhtree · Apr 14, 2016

Would it be solid?

Tegridy Reef · Apr 14, 2016

Didn't read it but I think would b cool to make the structure that u want and spray it with pond foam and glue rubble rock to it so u get the exact sculpture u want

adhd_nerd · Apr 14, 2016

Not sure it will work. It will probably float.

Glasswalker · Apr 14, 2016

First off, here are a couple pics of it one as just a skeleton, another a cut-away view. To show the internals.
This isn't solid, and the holes throughout the "skin" allow water flow/permeability into the internal structure which has high surface area.

Again this is a proof of concept, the intent would be to experiment a bit to dial in the specific best-case structure for the internals (best optimization of the structure for printability and best surface area). Right now it's not as dense as I'd like it, but I need to try printing it first to optimize from there.

Anyway here are the internal/cutaway pics I promised:

Internal Skeleton (without the skin):

Another Angle:

Cut-Away view of internals:

Another Angle:

Keep in mind this is just a test shape, I whipped it up pretty quick by hand. This technique would allow you to make this type of object with these properties in any base shape you like (for example, a 3D Scan of real live rock, or possibly your own custom shapes/sizes. Or a rectangular shelf for frags, or whatever you like).

Now to address some of the specific questions:

@kireek
I had thought of buffering being an obvious drawback, but as I mentioned, you could simply fill it with substrate via any one of the holes, unfortunately substrate is expensive, so it doesn't help with costing... The holes weren't actually designed for frags, but could work for that just fine. The holes were to provide access to internal surface area, and water flow-through capability. ABS machines relatively well, so you could cut/drill it as needed. However the advantage of 3D Printing is more that you could design the rock in any shape/size you like and print it like that from the beginning.

@revhtree
It would be filled with a lot of internal space. Definitely not "solid". It would be "structurally strong" though, if that's what you're asking. IE: you could use it as base-rock to support other structures most likely. Just how strong exactly would require some testing to find out it's failure point under load. But it's not a solid hunk of plastic, it's a structure containing a ton of internal space and surface area.

@That guy
Actually that's the whole point of 3D Printing, is that you design exactly what you want and the printer makes it for you. No need for more "conventional" manufacturing techniques. That said you could certainly add onto it, or combine it with other techniques. Or print multiple parts, and use the foam or conventional epoxy putty to join many together into larger structures, or combine with real rock as well.

@adhd_nerd
I'm fairly certain that it will not float, depending on how it's printed. ABS density is higher than that of water (about 1.2 g/cm3) but not too much higher density. The design allows water to penetrate all areas internally, shouldn't be any trapped air... That said it might require some adjusting to make sure the structure itself doesn't contain any air... It may still be just barely buoyant. As a result, either using it as base, with other rock, or using another means of attachment, or filling with a little bit of substrate should weigh it down just fine. Once tested, and refined the design should sink on it's own. That said it won't likely be heavy enough to be "rock solid" without some added weight or something.

I certainly appreciate all your feedback/questions. As I said in OP, I'm far from actually testing this in my tank, as it's still being built. But I thought the idea was cool and wanted to share it, and see if I could get input/feedback so I could refine it some. And perhaps someone out there with a mature tank would be interested in testing it out to help out in the research.

Thanks!

adhd_nerd · Apr 14, 2016

I think the act of heating and laying down filament traps enough air to change the density.

Glasswalker · Apr 14, 2016

adhd_nerd said:
I think the act of heating and laying down filament traps enough air to change the density.

True in some cases. Depends on the quality of your printer, and settings.

In most cases many of my prints have nearly no air being trapped as part of the heating/extruding process. And with correct settings there may be microscopic amounts of air trapped in a few places, but I'm pretty sure it doesn't alter the density. As a matter of fact I vaguely remember doing a buoyancy test on a printed solid part in the past and it sank. But I'll re-test to be sure.

That's in fresh water though, I do realize salt water has higher specific gravity and as a result impacts buoyancy.

As I said, to be tested/verified

I'm also considering trying different materials. PETG is food safe, and I believe I read on another thread most PET plastics are reef safe as well, these plastics are much nicer to work with than ABS, but have similar densities. Will be interesting to test different materials to see things like buoyancy, as well as how well things like coraline and such grow on it

jsker · Apr 14, 2016

I just skimming through, great idea. Did you say that you could design the rock to be like Legos, were you could make shapes with any piece? Now that would be aquascaping

Glasswalker · Apr 14, 2016

jsker said:
I just skimming through, great idea. Did you say that you could design the rock to be like Legos, were you could make shapes with any piece? Now that would be aquascaping

Hey! No actually that's not what I meant, but it's actually a great idea! (and totally possible) lol... Would need to come up with somewhat natural looking interlocking piece designs...

What I meant is that the technique for designing the 3D Model, allows me to turn any shape into this type of object with these properties. As a result, I could make a live rock shaped like Elvis's head for example, if you wanted the Elvis Reef lol... Or as I said make rectangular shelves for frags. And so on...

Mainly the experiment is to try and identify:

Is this method even viable? Will it turn "live"?
What are drawbacks/benefits, and so on.
What can we tweak to optimize it?

Once those things are nailed down, we can then look at different physical layouts/shapes using the technique. And I think making easy "building blocks" is a great idea! Thanks for suggesting it!

adhd_nerd · Apr 14, 2016

You are correct. You can get it to sink. I just tested a simple abs cone I printed that is a single .8mm thick and it sinks. I just wonder more complex structures. It will be a challenge to print those sample for sure; at least my 3D printer struggles with objects where there are lots of gaps and it has to retract/extract filament.

Glasswalker · Apr 14, 2016

This is one advantage a nice printer brings (And I'm aware that not all printers will be able to print this, the internal structure will require several hundred "islands" during print, which results in difficulties).

That said the #1 "complication" of printing many islands is stringing, which if you ask me will actually HELP the surface area of the internals do their job better lol. This is one case where a rough print is actually preferred

In my case my printer can do islands without breaking a sweat. CEL Robox, very nice retail printer, doesn't use retracts (actually has tiny needle valves in the tip of each extruder nozzle, which can immediately shut-off flow and turn it back on without any retracting, or oozing or anything). I can print multiple objects on a bed with hundreds of tiny parts, all in parallel, without any real stringing at all. Quality all turns out fine on each object.

I realize right now this is non-optimal. Mainly I'm fighting the slicers tendencies here. The slicer wants to make infill which is encased in a watertight shell, and has lots of air... The infill naturally has a ton of surface area and would work great for our needs except for some problems:

It's sealed in
It's linear (usually square grid, or hex honeycomb) which allows flow through in one direction only.

If however we could customize the infill algorithm to:

Not print a perimeter on the part, or at least print holes in it regularly
Regularly break the lateral surfaces on support material

It would be perfect for our purposes and any old object could be printed as "live rock" without any hand-tweaking at all... And it would get around the "difficult to print" issue, because we're working WITH the slicer instead of against it.

But for now just trying to prove if it's even viable. If so maybe I'll rewrite my own slicer to do this lol...

jsker · Apr 14, 2016

Glasswalker said:
Hey! No actually that's not what I meant, but it's actually a great idea! (and totally possible) lol... Would need to come up with somewhat natural looking interlocking piece designs...

What I meant is that the technique for designing the 3D Model, allows me to turn any shape into this type of object with these properties. As a result, I could make a live rock shaped like Elvis's head for example, if you wanted the Elvis Reef lol... Or as I said make rectangular shelves for frags. And so on...

Mainly the experiment is to try and identify:

Is this method even viable? Will it turn "live"?

What are drawbacks/benefits, and so on.

What can we tweak to optimize it?

Once those things are nailed down, we can then look at different physical layouts/shapes using the technique. And I think making easy "building blocks" is a great idea! Thanks for suggesting it!

Kind of my suggestion, come up with a fundimemtal foundation building block concept and anyone can build what they want out of your designed shapes using marine pure as your company to sub out your concept of blocks. You design the molds and have the fabercat the end result out of there product.

MasterBlaster66T · Apr 14, 2016

Wow this is awesome! I am extremely interested in this! I happen to be related to the owner of a print shop that has a commercial 3d printer, and have been thinking about setting up a tank in the shop I work at. I want to make an aquascape which resembles a particular shape to go with the shop and thought I would use live rock and cut it to shape/assemble with epoxy and acrylic rods. Now I am thinking this 3d printing idea will be much better for my needs! I can't wait for the test results. I am more than willing to help with the testing as well.
Also very cool you gave it a creative commons license, that will surely help to get the product into testing. It could be a money maker if the idea takes off and it could be made affordable. There are probably a lot of people who would like custom shapes in their aquariums.