3D Printers

louis · 2012-01-11 14:25:26

This technology seems to have come along nicely.

A gadget like this would be v. useful for a small colony.

But how easy would it be to produce the plastic I wonder? Could it be produced on a small scale without too much complex machinery. What do you need - carbon, hydrogen, fluorine, iodine??? (just educating myself on Wikipedia...

I wonder whether we (or I) have been too pessimistic about polymer production before now...Surely we could find some way to produce small amounts of plastic.

http://www.bbc.co.uk/news/technology-16503443

Glandu · 2012-01-12 07:22:07

Unlike previous 3D printers, this one seems like it might be something else than complete waste. Huge difference is : extrusion. All other printers I've been shown before wer just making heavy layers of unusable crap. With the right shape, & everything else(including mechanical properties) wrong.

I still do not buy the "can nearly replicate itself". By extruding, you can only form materials that are not heat-resistant. For extruding, you need a heat-resistant screw. And, of course, I fail to see how to make the electronics needed for converting bytes into movements.

Other limit is the mechanical quality of the made pieces. Can't be as bad as layered printing, yet extrusion is a tricky to properly balance - especially on asymetric pieces. The cooling down of the piece also has a strong effect on wether it will have good mechanical properties. For toys(the current application), it does not matter.

Anyways, I miss more accurate details to decide wether it can be useful. Yet, it might be. That's the first time I see a 3D printer that I don't dismiss at first sight. Cool.

louis · 2012-01-12 07:28:59

Good to know it isn't just me who sees this as something of a step change.

It would be good to get the formula for the plastic they use.

I think I may have a look on You Tube to see whether any backyarders make their own plastic.

Glandu · 2012-01-12 08:57:50

From far, looks like polyolefines. i.e. polyethylene or polypropylene. I might be wrong, though. Impossible to be sure without burning & smelling the damn thing(which I don't know to do anymore). If it smells like a candle when it burns, then it's polyolefines.

louis · 2012-01-12 15:17:08

Well if we going to Mars I would definitely put this guy in charge of small scale plastic production.

http://www.youtube.com/watch?v=anqKC0i0 … re=related

Obviously he's starting with something that is basically plastic,but he seems to be able to cope with small scale extrusion.

Very impressive.

Glandu · 2012-01-13 05:16:14

At the same time, you shall remember that each transformation (especially extrusion) significantly reduces the mechanical resistances of pieces you make. Recycling is not really an option, there.

Can be useful, but don't count on it for technical pieces.

louis · 2012-01-13 07:28:30

No - I wasn't counting on recycling plastic. But extrusion is part of the process for all types of plastic I believe, or most anyway, so I thought it was good to see it being done on such a small scale.
Remember, this is all home made stuff/assembly and he seems to have come up with a v. professional looking product.

For me, I am revising my proposals, and will now include polymer production. We can certainly get the hydrogen and carbon from the planet.

JoshNH4H · 2012-01-14 23:15:08

Louis- Do you remember the thread I posted a while back on the subject of polymer production? I believe I demonstrated that it will certainly be possible to produce some kinds of polymers. Polyethylene happened to not be one of these, though, seeing as it requires high temperatures and pressures, as well as ethene (Common name ethylene), which while certainly not impossible to synthesize will not be easy. That last sentence, by the way, is code for "Nothing's impossible, but I have no idea how to do it." If you want to look into it, I'd look at hydrocarbon cracking, or, as a last ditch, feeding hydrocarbons to microbes which secrete ethylene. The former may be expensive, and the latter will be highly inefficient.

For polymers, I think the primary ones we're looking at are Silicone and Melamine. Silicone is often used as a caulk (if you have a fish tank, the glass is probably sealed to get Melamine is one of the components of formica, though formica is actually a composite material. If you're interested in the production processes for either, I'd be glad to post them here, seeing as they were lost in the crash and I think they're good to have around. Keep in mind that polymers will require a significant input of energy to produce and this will make them more expensive than metals, especially more than Iron. This applies triple for Silicone, because silicon, which is obviously a vital component, is very difficult to produce. It might (I'm not sure about how often this reaction actually occurs) be possible to react SiO2 with chlorine gas at high temperatures to go straight to SiCl4, which would actually be a great help, when it comes to the production of silicone. I did the calculations, and this reaction can be favorable, but only at temperatures in excess of 3600 K. In short, it is not a viable process. It would help to reduce the change in energy, though I'm not sure how one would go about that. The normal strategy is an applied electric current, though how to do that is beyond me given that the reaction is between a nonconducting solid and a gas, and produces a nonconducting liquid which will not solvate ionic solids and a gas.

louis · 2012-01-15 07:24:08

JoshNH4H wrote:

Louis- Do you remember the thread I posted a while back on the subject of polymer production? I believe I demonstrated that it will certainly be possible to produce some kinds of polymers. Polyethylene happened to not be one of these, though, seeing as it requires high temperatures and pressures, as well as ethene (Common name ethylene), which while certainly not impossible to synthesize will not be easy. That last sentence, by the way, is code for "Nothing's impossible, but I have no idea how to do it." If you want to look into it, I'd look at hydrocarbon cracking, or, as a last ditch, feeding hydrocarbons to microbes which secrete ethylene. The former may be expensive, and the latter will be highly inefficient.
For polymers, I think the primary ones we're looking at are Silicone and Melamine. Silicone is often used as a caulk (if you have a fish tank, the glass is probably sealed to get Melamine is one of the components of formica, though formica is actually a composite material. If you're interested in the production processes for either, I'd be glad to post them here, seeing as they were lost in the crash and I think they're good to have around. Keep in mind that polymers will require a significant input of energy to produce and this will make them more expensive than metals, especially more than Iron. This applies triple for Silicone, because silicon, which is obviously a vital component, is very difficult to produce. It might (I'm not sure about how often this reaction actually occurs) be possible to react SiO2 with chlorine gas at high temperatures to go straight to SiCl4, which would actually be a great help, when it comes to the production of silicone. I did the calculations, and this reaction can be favorable, but only at temperatures in excess of 3600 K. In short, it is not a viable process. It would help to reduce the change in energy, though I'm not sure how one would go about that. The normal strategy is an applied electric current, though how to do that is beyond me given that the reaction is between a nonconducting solid and a gas, and produces a nonconducting liquid which will not solvate ionic solids and a gas.

Only vaguely I think. Thanks for those useful thoughts.

Glandu · 2012-01-16 09:22:26

louis, recycler wrote:

No - I wasn't counting on recycling plastic.

That's good, as plastics are not very good a it, & that's bad, because everything will be scarce on the red planet.

louis, extruder wrote:

But extrusion is part of the process for all types of plastic I believe, or most anyway, so I thought it was good to see it being done on such a small scale.

Nope. It's one method amongst many. Injection is usually the method used for complex parts; there is also thermoforming & rotomoulding. All those methods require complex, dedicated moulds, and are therefore not very useful for our needs. Extrusion, on the other hand, is ideal for making straight parts, i.e. with a profile that does not change(like tubes).

What is new to me in this method is the ability to reach complex forms without a dedicated mould. This is definitively new. But We lack accurate informations on the real quality of produced things.

louis, looker wrote:

Remember, this is all home made stuff/assembly and he seems to have come up with a v. professional looking product.

That's the problem with non-trained engineers : they tend to take "looking" for "real". What we need to have an accurate idea of the real potential of this thing is not easy to see : dimension tolerances, mechanical resistances, shape limits. Those things are important. remember, we don't go on Mars for building toys. We will need high-quality technical pieces, & that's another deal. Can this machine fulfill? Their marketing blahblah does not give any answer.

Even if the answer is no, that's a nice little machine, by the way... I'd love one at home(no place for that unfortunately).

louis, plastic maker wrote:

For me, I am revising my proposals, and will now include polymer production. We can certainly get the hydrogen and carbon from the planet.

As said by others, complex. Worth it? No clue, unfortunately.

And silicones & melamines are different babies than polyethylene when it comes to transformation. Melamine is a thermoset, not a thermoplastic, and therefore more liquid before transformation. I highly doubt you can extrude melamine(and I'm pretty sure). For silicones, a quick search didn't give me enough elements, but my long-term memory makes me doubt it could work for them also(but that's an heavy uneducated guess).

Which made me reread the BBC article. I think there is a mistake. They speak of 40mm per second, and 20 minutes for making a small piece. Must be 40mm per minute. Or 20 seconds for making the piece. It would lead to radically different conclusions.
==>If it's fast, then it's nearly like real-life extrusion, & you need a very visquous(spelling?) kind of polyolefine. It makes having the right polymer on Mars rather tough. If profile does not change suddenly
==>If it's slow, it means they have some special behaviour to pass correctly through the end & keep everything at the right temperature. Internal structure of the piece must be rather strange, garbled, & mechanical properties rather ugly. At the same time, accuracy of the piece must be greater.

Conclusion : I'm teased. I need to know more. Aaaaargh. Plus I'm at work & can't check youtube. Aaaaargh again.

Adaptation · 2012-01-16 21:58:35

3d printing is one of the slowest forms of manufacture and produces inferior parts to injected or machined parts. We have a very nice 3d printer and we use it all the time for prototyping and mold making. A good well programmed five axis cnc with a tool changer can can machine out just about anything faster than the printer can print it. The reason we still use the printer is because skilled man power to program the milling machine is at a premium and the cnc is often occupied with production work. On mars or the moon I would prefer to see multi-axis cnc lathes and mills programmed from earth doing most of the work. The one big exception would be for very small parts, a small wax printer used in investment vacuum centrifugal casting can produce some of the highest quality small intricate parts even from high performance alloys that are normal difficult to cast.

Glandu · 2012-01-17 04:34:43

Ah, at least someone who understands my doubts(and goes even further). Someone who really works in the domain, seems like. I feel less alone.

Just, this specific machine possibly could do things that machining couldn't do, i.e. complex shapes inside the piece. In one single piece. That's not a common need, though.

But, other than that, I tend to agree with you : better machine 19th century fashion - with 21st century control.

louis · 2012-01-17 16:10:25

Adaptation wrote:

3d printing is one of the slowest forms of manufacture and produces inferior parts to injected or machined parts. We have a very nice 3d printer and we use it all the time for prototyping and mold making. A good well programmed five axis cnc with a tool changer can can machine out just about anything faster than the printer can print it. The reason we still use the printer is because skilled man power to program the milling machine is at a premium and the cnc is often occupied with production work. On mars or the moon I would prefer to see multi-axis cnc lathes and mills programmed from earth doing most of the work. The one big exception would be for very small parts, a small wax printer used in investment vacuum centrifugal casting can produce some of the highest quality small intricate parts even from high performance alloys that are normal difficult to cast.

How old is your 3 D printer?

Did you look at my original post? The output from these new printers seems pretty good, and of course this is without the benefit of tens of millions of pounds of funding that would be available for a Mars ISRU project.

Adaptation · 2012-01-17 21:26:24

Its a couple years old, I think we spend around 30k on it.

louis · 2012-01-18 08:47:57

Well if you haven't taken a look at this machine ,please do - it seems a real advance.

JoshNH4H · 2012-01-18 09:52:35

Glandu-

I wouldn't be surprised if a thermosetting polymer could not be properly formed by extrusion or injection or many of the other methods which are traditionally used for polymers. On the other hand, wouldn't a thermosetting polymer be possible to form via more traditional measures, as used for metals, e.g., by pouring (perhaps pressing, I suppose, depending on viscosity- which reminds me, it's technically "viscous"- I had almost forgotten you weren't a native speaker of English, haha ), and then heating it to make it stay in that shape?

Silicone is generally not too useful for shaping into specific objects, so far as I know, though I have definitely seen kids' toys which were made of silicone rubber. I'm not quite sure how that was done. The general process for the manufacture of silicone involves treating Si(CH3)2Cl2 with water, leading to a reaction which produces silicone rubber and HCl. There is apparently a slower alternative method which uses acetate and produces Acetic acid, but this is from wikipedia so I can't even verify my memory at present seeing as English language wikipedia is down to protest SOPA and PIPA. I would add, though, that if it is possible to do with acetic acid, it should also be possible with methanoic acid (Common name: Formic acid, IIRC), but on Earth I believe the two-carbon organics are actually generally cheaper than the one-carbon, because of the wide availability of ethanol. In this case, I suppose we would have to ask ourselves which is more undesirable- methanoic acid or hydrochloric . I would imagine hydrochloric, actually, since it's not toxic, just caustic, which can be neutralized through the application of some amphoteric or basic substance.

Silicone is particularly good for making seals, seeing as it functions as a caulk on Earth. Whether it will later be possible to melt down and reform I can't say. I would use the thermosets for objects which need to be shaped.

How much do you know about the properties of melamine resin, in terms of strength and other relevant properties for parts made from it?

Adaptation · 2012-01-18 14:06:06

Vulcanized or cured silicone cannot be melted, it will decompose before that happens.

Terraformer · 2012-01-18 14:51:24

Google is your absent-minded friend, Josh - http://webcache.googleusercontent.com/s … clnk&gl=uk

Terraformer · 2012-01-18 15:41:16

Anyway, you can access Wikipedia if you follow their instructions - http://meta.wikimedia.org/wiki/English_ … hnical_FAQ

For Silicone, it might be best to go with the Acetate route - Ethanoic Acid isn't particularly toxic or caustic, and it means we don't have to locate reserves of Chlorine.

JoshNH4H · 2012-01-18 21:44:51

I actually wrote that post from my phone; However, I felt that I should honor Wikipedia's blackout in protest of SOPA and PIPA.

Adaptation, I don't know much about silicone, and I am willing to accept that it may decompose, though according to some very quick research Silicone decomposition on Earth is a result of oxidation rather than true chemical decomposition. I don't think Silicone is particularly useful except as a sealant, though, so this isn't a big deal.

Terraformer, the problem with using ethanoic acid (for those who don't know IUPAC nomenclature, Acetic Acid, aka the active ingredient in Vinegar) is neither acidity (it's pretty weak as far as acids go, after all) nor toxicity (After all, we can safely drink it). Rather, the problem is that it's fairly difficult to make two-carbon compounds on Mars, seeing as biological routes are highly inefficient, and demand for silicone will be fairly significant, given the need to make things airtight everywhere.

Adaptation · 2012-01-18 23:13:41

You can safely drink it in like 3% concentration. And I don't even know how safe that is my brother drank some on a dare and it gave him a rather nasty upset stomach I'm willing to bet if you drank it too often it could do some real damage.

Terraformer · 2012-01-19 04:22:16

However, it's going to essentially be a catalyst, so we're going to be reusing a lot of it. As for it's production biologically, we're looking at 5 percent effiency, right? Granted, that's low, but remember we're using it as a catalyst. Also, if you're using domes, you have to take into account the cost difference of sunlight and electricity.

We'll need some that uses Acetate anyway, for the reasons mentioned in the Wikipedia entry...

JoshNH4H · 2012-01-19 12:21:21

Adaptation-

Which compound do you speak of, Hydrochloric acid, or Ethanoic (Acetic) Acid? Obviously there's a big difference.

Terraformer- Where do you get 5% from? Chances are we would be producing it from waste crop material, which would not be 5% efficient, it would be less, as well as being more labor and resource intensive. Having produced the plant, you would then have to ferment. Ideally it would be possible to produce acetic acid by chemical means. That said, a vat full of chlorella wouldn't be too bad; We're not looking to produce some high quality vinegar, though I suppose we do want high concentration.

Reading the Wikipedia article a bit more, it actually looks as if the method of choice for the production of Ethanoic Acid isn't fermentation, but carbonylation of methanol, requiring, in addition to a Hydrogen Iodide and Metal Carbonyl catalyst. The Iodine will be imported presumably, unless we get lucky and we happen to discover a bit, while Iron pentacarbonyl will probably be used as the metal carbonyl. Here's the relevant section of the Wikipedia article and for more information this pdf seems to give a pretty good overview, though I didn't read it in its entirety. Given this newfound ability to produce ethanoic acid, if we have a source of ethene (ethylene), which we can get via hydrocarbon cracking of Methane, it will be possible to make the Vinyl Acetate monomer, which can be polymerized by radical chain polymerization to Poly Vinyl Acetate (PVAc), which in solution with water apparently makes a good glue.

From PVAc, it also seems like it is possible to react your way to a fairly wide variety of complex organic chemicals, which is always a good thing.

Glandu · 2012-01-20 04:38:35

JoshNH4H wrote:

Glandu-
I wouldn't be surprised if a thermosetting polymer could not be properly formed by extrusion or injection or many of the other methods which are traditionally used for polymers. On the other hand, wouldn't a thermosetting polymer be possible to form via more traditional measures, as used for metals, e.g., by pouring (perhaps pressing, I suppose, depending on viscosity- which reminds me, it's technically "viscous"- I had almost forgotten you weren't a native speaker of English, haha ), and then heating it to make it stay in that shape?

"pouring" & hardening after is the exact principle of extrusion. Just, "hardening" is done by cooling down, not heating up(works for thermoplastics, lead, & probably other stuff). "hardening" by cooking seems unlikely to me, as it's a longer process : you modifiy the chemical structure of your atoms, instead of simply freezing them when you go the cold route.

I don't say it's impossible, just I haven't heard anything that makes me think it's a good idea. And I've heard a lot.

JoshNH4H wrote:

Silicone is generally not too useful for shaping into specific objects, so far as I know, though I have definitely seen kids' toys which were made of silicone rubber. I'm not quite sure how that was done. The general process for the manufacture of silicone involves treating Si(CH3)2Cl2 with water, leading to a reaction which produces silicone rubber and HCl. There is apparently a slower alternative method which uses acetate and produces Acetic acid, but this is from wikipedia so I can't even verify my memory at present seeing as English language wikipedia is down to protest SOPA and PIPA. I would add, though, that if it is possible to do with acetic acid, it should also be possible with methanoic acid (Common name: Formic acid, IIRC), but on Earth I believe the two-carbon organics are actually generally cheaper than the one-carbon, because of the wide availability of ethanol. In this case, I suppose we would have to ask ourselves which is more undesirable- methanoic acid or hydrochloric . I would imagine hydrochloric, actually, since it's not toxic, just caustic, which can be neutralized through the application of some amphoteric or basic substance.

As always, chemical is only half of the way.

JoshNH4H wrote:

Silicone is particularly good for making seals, seeing as it functions as a caulk on Earth. Whether it will later be possible to melt down and reform I can't say. I would use the thermosets for objects which need to be shaped.

The only recycling known for thermosets is to burn it(and get the energy). But they require less heavy machinery than thermoplastics, usually. Silicone, from what I did read, seems not really recyclable either.

JoshNH4H wrote:

How much do you know about the properties of melamine resin, in terms of strength and other relevant properties for parts made from it?

IIRC, that's like standard plastic. Just, obviously, more heat-resistant, & less shock-resistant. As any thermoplastic or thermoset(besides polybenzimidazole, a bitch to produce & to shape), it's really weak compared to good old steel.

My 2009/2010 posts about plastics(inspired by highly optimistic polymer plans of mars homestead) have disappeared, yet I still think that good old steel should be enough for most uses : easy to shape with very few machines and resistant to everything. Of course it's heavy, but it's only 38% as annoying on Mars than on Earth.

JoshNH4H · 2012-01-20 14:17:13

Glandu (Still have the urge to call you El Slapper, even though it's been almost two months that Newmars has been back)-

As always, your expertise in the matter is much appreciated.

wrt Thermosetting polymers, I suppose the problem is that I lack knowledge of the methods usually used on Earth. How are thermosetting polymers usually formed into objects in an Earth-based factory?

I would not be surprised if silicone is not recyclable. After all, there seems to be little reason why it would be. Standard procedure will probably be to extract the silicon and either burn the rest (e.g., the methane) or send it back through the chemical production facilities.

I don't doubt that metals will suffice in a wide variety of applications. They are, after all, stronger, require less energy to produce (per kilo, at least, probably not per liter), and sound like they're much more workable, especially at a smaller scale. Nevertheless, I'm sure some need for plastics will remain so I would like to have some options available.

Also, it occurs to me that it will probably be impossible to recover the acetic acid when silicone is being used as a caulk. It happens, I suppose.

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