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#51 2012-01-30 09:22:37

Glandu
Member
From: France
Registered: 2011-11-23
Posts: 106

Re: 3D Printers

Argh, lost my answer due to bad manoeuver. Shouldn't post while I'm working..... second try :

JoshNH4H, thermosetter wrote:

Glandu-

For making things out of thermosets, is their viscosity low enough that you can actually pour the resin into the mold, or is it still necessary to apply some small amount of force to get it into the mold?

Given you input, I was clearly wrong about my thermoset suggestion.

Depends on the resin. Not much strength, though. Molds can be kepts simple(unlike molds for thermoplastics).

JoshNH4H, optimist wrote:

While some experimenting would have to be done, there's no particular reason why using basalt fiber cloth would not work outside.  There's nothing conductive out there and nothing that could corrode the wires to any significant degree, especially not in the dry cold.

Well, it has to be experimented before being validated. Sounds promising, though.

JoshNH4H, insider wrote:

Inside is a different story, but water in the air does not make the air conductive.  It would really only be a problem if the wire were at a significantly lower temperature than the air surrounding it.  That said, indoors it's always a good idea to protect from water, and seeing as the actual use of silicone in terms of volume will be pretty minimal the additional safety is definitely worth it.

Water in the air goes everywhere, corrodes everything, accumulate in the most unlikely places, & causes short-circuits. If silicone works, I take, but you definitively need something water-tight.

JoshNH4H, composer wrote:

I don't think that the composite will be as difficult to make as you suggest in this case, because you can, to my understanding, basically paint the silicone on.  On the other hand, my suggestion that you would use a composite was mostly due to my not thinking about it.

You paint on a mold. Or at least half-mold. Same goes for composites, btw. For most thermosets, you need both faces of the mold.

If you need 1 single piece, then better machine it in steel than machining a similar mold, then painting over it. Long before reaching the 100's of people, you"ll already need extended manufacturing capabilities(local store is just too far). For complex shapes, you'll need to make it in one shot. That's why rapid prototyping is appealing. But it's a complex issue.

Louis, caster wrote:

Here's  a link to a paper on casting basalt as you cast iron.
http://www.cbpengineering.com/pdf/Mater … ptive).pdf
So I think it could be used to make vessels and possibly tools of various kinds.

Remember that you need a model for that, plus sand. it's doable, but also there, has a meaning for greater series. The model, though, is likely to be easier to machine than a mold for the same piece.


"I promise not to exclude from consideration any idea based on its source, but to consider ideas across schools and heritages in order to find the ones that best suit the current situation." (Alistair Cockburn, Oath of Non-Allegiance)

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#52 2012-01-31 14:27:50

JoshNH4H
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From: Pullman, WA
Registered: 2007-07-15
Posts: 2,526
Website

Re: 3D Printers

Well, first of all on cement: This powerpoint by 4frontiers suggests Sorel Cement, which is made of a mixture of magnesium oxide and magnesium chloride.  On the plus side, it is apparently much simpler to obtain these materials on Mars than the calcium-based ones used in portland cement, which is usually the material of choice on Earth.  On the downside, this cement will be vulnerable to attack by water.  I don't think that will be such a big deal, seeing as Mars is incredibly dry.  The bigger deal is actually probably going to be the cold temperatures on Mars.  I know KSR mentioned in Red Mars that there might be issues with concrete not setting because of the cold.  I don't know if this will be an issue in real life, can anyone comment?  If it will be, any ideas on what could be done to get a concrete equivalent that would not be subject to this problem?

Glandu-

That generally sounds like good news on the polymer front.  I'm really coming to like cast basalt as a construction material.  It is unfortunate that it would not be possible to composite it with basalt fiber, though.  I suppose if a composite of that nature is needed it will be done with bricks.

Might I suggest that the mold would be made originally by getting cast basalt into approximately the correct shape, then covering it with thermosetting plastic, shaping that, and then forming the mold around it?  That seems like the most effective way to go about it.


-Josh

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#53 2012-01-31 15:30:17

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 3,756
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Re: 3D Printers

I have my doubts that concrete as we know it would ever cure in intense cold,  unless the water in it remained liquid.  The hydration reaction requires liquid water. 

I could cast slabs down to about 29 F (-2 C),  but only because the cure is very slightly exothermic,  and the slab never cooled below 32 F (0 C) until the "cure" was finished. 

And,  that only gets it to "walk-on-it" strength.  Typically,  concrete slowly cures further over about 30 days to its full strength.  It's not exothermic enough to get a difference from ambient during this period. 

I rather suspect we'd need a new kind of concrete on Mars.  Something will work,  just not what we do here. 

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#54 2012-01-31 22:46:54

JoshNH4H
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From: Pullman, WA
Registered: 2007-07-15
Posts: 2,526
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Re: 3D Printers

GW-

That seems like a pretty fair assessment.  Traditional forms of concrete aren't necessarily totally off the table, in that a lot of times they're useful, even pre-formed (though sintered regolith or cast basalt is probably better here), plus it is conceivable to heat it.  Energy intensive, though, and not desirable.  Since this is an interesting topic, I think I'm going to go make another thread on the issue, seeing as there is definitely scope for a martian (carbonate based?) concrete.  Or bricks.  The only issue with bricks is that you still need a mortar to hold them together.


-Josh

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#55 2012-02-01 08:43:08

Glandu
Member
From: France
Registered: 2011-11-23
Posts: 106

Re: 3D Printers

JoshNH4H, composite wrote:

That generally sounds like good news on the polymer front.  I'm really coming to like cast basalt as a construction material.  It is unfortunate that it would not be possible to composite it with basalt fiber, though.  I suppose if a composite of that nature is needed it will be done with bricks.

A composite with fibers of itself? That's ..... mind-bending. It probably won't work because fibers will simply smelt into the matrix, and mix with them. And it's probably useless, as if you already have the strength of basalt as a whole, then basalt-fiber won't help.

For what use did you have this idea in mind? I don't thow your idea right now in the bin, but I cannot see how it could be useful(or done).

JoshNH4H, complicated wrote:

Might I suggest that the mold would be made originally by getting cast basalt into approximately the correct shape, then covering it with thermosetting plastic, shaping that, and then forming the mold around it?  That seems like the most effective way to go about it.

We will need machining capabilities. Most spare pieces of mechanical tools can't be cast, or hand-made, or whatever. They can be only machined. It's mandatory for surface quality.

Then why do you need such a complicated way for doing the model? Just take some metal(probably steel, maybe something lighter if available), machine it as accurately as possible, and use it as a model. If the model is too complicated for being made in 1 piece, assemble several machined pieces together with rivets/screws/whatever. Then cast.

If your first model is not accurate, you'll have to deal with variations of thickness of your thermoset. That's no good news. When cooling, the whole thing will have a set of strange, unwanted behaviours. And if your first model is accurate, you don't need a second one.

Or then there you can use a 3D printer. Your model can be absolute crap in terms of mechanical properties, as long as you can put your sand around. Hell, even if Louis's link is not as promising as it sounds, I've maybe found a usefulness to those not-that-wonderful machines.


"I promise not to exclude from consideration any idea based on its source, but to consider ideas across schools and heritages in order to find the ones that best suit the current situation." (Alistair Cockburn, Oath of Non-Allegiance)

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#56 2012-02-01 16:44:56

JoshNH4H
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From: Pullman, WA
Registered: 2007-07-15
Posts: 2,526
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Re: 3D Printers

A composite with fibers of itself? That's ..... mind-bending. It probably won't work because fibers will simply smelt into the matrix, and mix with them. And it's probably useless, as if you already have the strength of basalt as a whole, then basalt-fiber won't help.

For what use did you have this idea in mind? I don't thow your idea right now in the bin, but I cannot see how it could be useful(or done).

Well, it would be useful because, oddly enough, while cast basalt has a strength of approximately 10 MPa, Basalt Fibers have a tensile strength of 4500 MPa.  Big difference, no?  Making a composite of these two materials could very easily result in a new material with much improved tensile properties.  I can't comment on the reasons for this difference.  This is similar in concept to the Reinforced Carbon-Carbon composite used on the Space Shuttle.  That one is Graphite and Carbon Fiber, IIRC.

I'm not sure what particular uses this material would have, if it were possible to fabricate, but surely it is always useful to have a higher-strength analogue to the usual construction materials available, in case it is needed.

We will need machining capabilities. Most spare pieces of mechanical tools can't be cast, or hand-made, or whatever. They can be only machined. It's mandatory for surface quality.

Then why do you need such a complicated way for doing the model? Just take some metal(probably steel, maybe something lighter if available), machine it as accurately as possible, and use it as a model. If the model is too complicated for being made in 1 piece, assemble several machined pieces together with rivets/screws/whatever. Then cast.

If your first model is not accurate, you'll have to deal with variations of thickness of your thermoset. That's no good news. When cooling, the whole thing will have a set of strange, unwanted behaviours. And if your first model is accurate, you don't need a second one.

Or then there you can use a 3D printer. Your model can be absolute crap in terms of mechanical properties, as long as you can put your sand around. Hell, even if Louis's link is not as promising as it sounds, I've maybe found a usefulness to those not-that-wonderful machines.

I don't doubt that the colony will need to have machining capabilities.  I was just thinking in terms of ways to minimize the cost of the models, seeing as Iron production on Mars will be akin to Aluminium production on Earth in that it will be quite energy intensive.  Cast basalt production will use much less energy, but it's not really machinable, it would have to be covered in something that is.  I'm not sure what a cost benefit would show, and I guess it doesn't really matter seeing as these  will probably be one use anyway.


-Josh

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#57 2012-02-02 04:55:33

Glandu
Member
From: France
Registered: 2011-11-23
Posts: 106

Re: 3D Printers

JoshNH4H wrote:

Well, it would be useful because, oddly enough, while cast basalt has a strength of approximately 10 MPa, Basalt Fibers have a tensile strength of 4500 MPa.  Big difference, no?  Making a composite of these two materials could very easily result in a new material with much improved tensile properties.  I can't comment on the reasons for this difference.  This is similar in concept to the Reinforced Carbon-Carbon composite used on the Space Shuttle.  That one is Graphite and Carbon Fiber, IIRC.

I'm not sure what particular uses this material would have, if it were possible to fabricate, but surely it is always useful to have a higher-strength analogue to the usual construction materials available, in case it is needed.

I see. 10 MPa is really crappy, though. It makes me doubt about the usefulness of cast basalt. And plain basalt still needs too much heat for being a usable matrix, I fear. Imagine a steel wire. Drown it into smelted steel. Not sure it will survive & keep its properties.

My uneducated guess is that basalt fiber is strong because of internal chemical orientation of molecules. That one would be destroyed by excessive heating.

JoshNH4H wrote:

I don't doubt that the colony will need to have machining capabilities.  I was just thinking in terms of ways to minimize the cost of the models, seeing as Iron production on Mars will be akin to Aluminium production on Earth in that it will be quite energy intensive.  Cast basalt production will use much less energy, but it's not really machinable, it would have to be covered in something that is.  I'm not sure what a cost benefit would show, and I guess it doesn't really matter seeing as these  will probably be one use anyway.

But thermosets won't be cheap either, I fear. Here I go again with my mantra : molding is not something easy, neither cheap, for such a small-scale society. It's not magic reproduction of pieces, & requires a lot of investment.


"I promise not to exclude from consideration any idea based on its source, but to consider ideas across schools and heritages in order to find the ones that best suit the current situation." (Alistair Cockburn, Oath of Non-Allegiance)

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#58 2012-02-02 15:57:10

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 3,756
Website

Re: 3D Printers

To reinforce something with basalt fibers means you can't heat to basalt meltpoint,  or the fibers melt.  Use those fibers as the reinforcement in some other matrix instead. 

How about ice?  I once froze a wet dishrag,  and used it as a bat to hit a ball a very long way indeed.  Mars is a cold place.  Basalt fiber-reinforced ice might be a pretty good building material.  Bricks and panels. 

Or a blend of materials: 

Compression members could be ice with a regolith aggregate in it,  analogous to concrete.  For bending and tension situations,  imbed some ropes made of basalt fiber to act as the rebar. 

Ice and basalt seem plentiful on Mars,  although individual sites most likely vary a lot.  There just might be a real future for ice-regolith-basalt fiber as the analog to reinforced concrete. 

Toughest part is melting the basalt.  It would be nice if someone spotted an active volcano with basaltic lava. 

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#59 2012-02-06 04:22:49

Glandu
Member
From: France
Registered: 2011-11-23
Posts: 106

Re: 3D Printers

Composites are not just matrix + cloth. They usually imply some chemical coating of the cloth, so that there is some "gluing" of the matrix & the cloth. If not, you end up with micro-bubbles everywhere, and those are a pre-made damage to your structural integrity.

Infos about ice+basalt composite on google is no existant. Probably because here on earth it makes no sense, & noone ever tried. On Mars it could work, but a lot of work is needed so that you ensure the matrix is glued to the cloth. No need for a strong link : just enough to weed bubbles.



The "concrete" you speak about is a different kind of things. Pre-tensed concrete is not a "composite", in the sense that you have no glue between concrete & steel(on earth), & it does not matter. In terms of mechanical resistance, you have concrete with holes, & sticks in those holes, with a mechanical push inwards from both sides of the concrete.

Therefore, your idea hols potential - no more need for a "glue". OTOH, you have to make the "regolith icy concrete" have some mechanical properties by itself. Not much, but enough, especially in compression resistance. Pre-tension makes sense only on compression-strong, traction-weak materials(as, you guessed it, concrete). If your regolith-ice mix behaves the same(but I have no clue about it), then it would be an elegant  & efficient solution. If...


"I promise not to exclude from consideration any idea based on its source, but to consider ideas across schools and heritages in order to find the ones that best suit the current situation." (Alistair Cockburn, Oath of Non-Allegiance)

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#60 2012-02-07 22:00:42

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 3,756
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Re: 3D Printers

Cold ice absent any liquid phase seems to stick to things pretty good,  essentially being its own glue.  That's why little boys who stick out their tongues and touch them to light poles on sub-zero days (that's under 0 F, = to temps under about -15 C for you metric types) get stuck there until someone frees them by melting the ice bond with a warm liquid.  My frozen dishrag bat was pretty stout,  too. 

Concrete's matrix,  Portland cement,  actually has rather poor bonding to its aggregate or to its rebar.  That's why the rebar is not smooth bar stock,  it has formed circumferential ribs that protrude into the concrete,  for a simple mechanical lock against actually sliding through the concrete.  Check out the broken surface of concrete rubble some time.  It's not very hard to pry out some of the aggregate rocks,  if about half of the rock protrudes,  so that it is not mechanically locked. 

Designing experience with concrete suggests that simple rebar reinforced concrete is capable of some fairly-limited but non-zero tensile and bending resistance.  Concrete highway bridge beams have a different reinforcement:  a tensile steel rod (or rods) protruding out both ends,  onto which nuts and thrust washers are added at each end.  These tensile rods ride loose inside tubes embedded in the beam.  These rods are really savagely torqued down,  pulling very heavy tension on the steel rod(s).  This force's static reaction exerts a compression load on the ends of the concrete beam,  by means of bearing forces under the washers at each end.  By substantially pre-loading the entire concrete beam in compression this way,  a much larger bending stress can be endured without exceeding the concrete's limited tensile strength on the tensile side of the beam's stress distribution.  This is called a pre-stressed beam. 

I rather think that ice could replace Portland cement,  local rocks on Mars can be the aggregate (as long as you tumble them to be rounded of shape),  and thick braided ropes of basalt fiber could serve as a sort of rebar,  since the surface of the rope has enough porosity plus the braided texture to mechanically lock it into the ice,  if nothing else.  Light duty plastic pipe and steel rods could serve as pre-stressing members,  the same way they do here,  for substantial beam bending resistance as standard pre-stressed beams. 

If energy is too dear to expend on melting basalt to process the fiber,  then we have to bite the bullet and import steel rebar from Earth. 

Finding iron ore on Mars will be very important.  A source of carbon for the refining and alloying processes is required.  If Phobos is a carbonaceous chondrite,  then there's a carbon mine.  A source of copious energy will be required:  steel-making is extremely energy intensive.  But in the longer term,  cheap steel is utterly essential to the viability of any industrial/technological society.  Unpleasant fact of life,  but there it is. 

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#61 2012-05-31 20:09:05

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 17,390

Re: 3D Printers

New member Paul of MarsDrive had this post:

After reading through some sections of Mars Drive's site, and reading about the Mars Workbench and the idea of displaying prototypes at events to generate public interest, I had the following (rather nebulous) idea. I hope it can be of some use.

Here in the states there is a company called TechShop which is a rapidly growing chain of hackerspaces, and Maker Faire which is a get-together for people who like to build their own stuff - high tech, low tech - anything. There are local Maker Faires held all around the world - Dublin, London, Manchester, Melbourne - and they are attended by people excited about building cool things. Seems just what you need.

Also, DARPA has just signed a contract with TechShop to build 2 new TechShop sites that DARPA will use at night to test new manufacturing ideas.

Do you suppose that other governments - eager to show they are "on the cutting edge", but strapped for cash - might be sold on the idea of low cost R&D at local hackerspaces? Can you imagine a good test project?
Might universities be competitive in their search for low cost high publicity opportunities to demonstrate their bona fides? Can Mars Drive suggest suitable test cases?
Could the X-Pize folks or the 100 Year StarShip group be talked into crowdsourced R&D, with perhaps suitable prizes for the winning teams?

Here are some relevant links:
http://www.darpa.mil/NewsEvents/Release … 05/24.aspx
https://en.wikipedia.org/wiki/TechShop
https://en.wikipedia.org/wiki/Maker_Faire
http://makerfaire.com/map.html
http://www.businessweek.com/articles/20 … -tinkerers

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#62 2012-07-23 14:45:41

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 3,756
Website

Re: 3D Printers

Back to 3-D printers:  I saw recently that they were 3-D printing in powdered metal now.  That's pretty slick.  And yesterday I saw that NASA is trying out some sort of 3-D printing rig in the zero-gee airplane.  The idea has definite potential. 

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#63 2014-05-31 20:43:12

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 17,390

Re: 3D Printers

The world's first rocket thruster to be fabricated on a 3-D printer was certified by SpaceX today.

rcj_SpaceX_3D_3-D_Printing_Rocket_Thruster_Space.jpg.jpeg

SpaceX 3D Prints Rocket Thruster

No longer are 3D printers a novelty for kids, or even just a tool for prototyping, now that the world's first production rocket thruster to be qualified for space flight was certified today by Space Exploration Technologies Corp. in SpaceX, Hawthorne, Calif. According to SpaceX, 3D printing can drastically cut the cost and time of manufacturing finished parts for space vehicles and by implication for any vehicle. Will Google's next driverless car be 3D printed?

Called the SuperDraco thruster, eight will power the Dragon spacecraft for both the launch escape-from-gravity system as well as for coordinated Earth landings -- Flash Gordon-style. The Draco engines were originally designed only for maneuvering the spacecraft in orbit and to assist during re-entry. The upgraded SuperDracos now produce 16,000 pounds of thrust plus the deep throttle capability that gives astronauts the ability to make pinpoint landings.

The SuperDraco engine is 3D printed using direct metal laser sintering (DMLS) -- originally developed by EOS GmbH in Munich, Germany -- using a high-performance superalloy called Inconel--a carbon-laced nickel-chromium alloy trademarked by Special Metals Corp. in New Hartford, NY.

The SuperDraco will further lower the cost of launching SpaceX spacecraft by supplying the escapee-form-gravity propulsion which was previously provided by a separate rocket that was jettisoned after launch. The system is also safer since one of the eight SuperDraco's can fail without endangering the mission. The SuperDraco's have also been repositioned to ensure that in the case of an emergency during launch they can provide 120,000 pounds of axial thrust, enough to land the spacecraft safely.

The first use of a SuperDraco-powered spacecraft will be in a pad-abort-test later in 2014 as a part of NASA's Commercial Crew Integrated Capabilities (CCiCap) initiative.

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#64 2014-06-02 07:58:23

Glandu
Member
From: France
Registered: 2011-11-23
Posts: 106

Re: 3D Printers

Impressive.

Can't be as good as the same piece forged - but if the shape is too complex for being forged, the advantage of 3D printing is obvious.

My uneducated guess is that they rework the parts after impression for better mecanical performances. Still, impressive(and iven more if not the case).


"I promise not to exclude from consideration any idea based on its source, but to consider ideas across schools and heritages in order to find the ones that best suit the current situation." (Alistair Cockburn, Oath of Non-Allegiance)

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#65 2014-11-29 22:27:51

Impaler
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From: South Hill, Virginia
Registered: 2012-05-14
Posts: 286

Re: 3D Printers

A 3D printer recently sent to ISS has been given a try and has made some experimental parts which will be returned to earth an compared with equivalent made on Earth with the same machine.  See here from the site of the developer of the zero-g printer (it's is a space-ruggedized normal ABS plastic printer) http://www.madeinspace.us/nasa-and-made … t-in-space

Despite some skepticism on my part towards 3D printing (more the notion by some folks that 3D printing completely replaces normal manufacturing) the folks doing this (Made in Space) talk about very concrete uses for the technology.  They emphasis points like making small components necessary to correct or modify unforeseen defects in experiments sent to the ISS.  That is a significant improvement in the original justification for having human run experiments, that they would be able to 'fix' things and save experiments that would otherwise be wasted on an unmanned satellite.  Without spare parts their have been doing little more then 'observing' and 'fiddling' but with simple plastic parts a lot can be done.   The incredible diversity of the experiments on ISS means that their is no way to stock spares for them so their really is no substitute for this.

The spare part issue is addressed too, they claim that NASA analysis shows a 3D printer could make 30% of the parts that have failed over the ISS lifespan.  Now I'm sure that a parado-anlysis would show that 30% to be much more to the low-end non-critical stuff like straps, locker hatches, bits of exercise equipment etc etc.  Still that is a start and with improved printers capable of a wider set of materials the spare replacement capacity could be pushed to cover some actual mission critical parts.

They also addressed material sourcing, first they are looking to grind old parts directly into the printer.  While plastic is not infinitely recyclable in this way it can perform adequately so long as the regrind ratio is low enough, still it's a significant source stock if you have designed your spacecraft to be initially made of the same plastic so every break-down is a recycle opportunity, obviously it's too late to do that on ISS as it's already built but future space vehicles may try this.  In addition they examined the potential to utilize the ISS trash stream (of which their is a LOT due to food packaging and foam padding needed during liftoff) as a material source.  Another unmentioned source would be scavenged components of completed experiments.  Crew labor time might be an issue though in doing all this recycling, here on Earth it is notoriously time-consuming to recycle stuff and it only happens when very cheap labor is available, and astronaut labor is estimated at >$50,000 an hour so don't expect them to become diligent recyclers any time soon.

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#66 2015-02-16 11:31:45

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 17,390

Re: 3D Printers

GW Johnson wrote:

Void wrote:

louis wrote:

I think perhaps you are overstating the amount of cargo that needs to be exported to Mars, once a functioning base is established. 

With ISRU on Mars, you can:

1. Manufacture Earth-like air.

2. Generate electricity from concentrated solar heating and steam engines built on Mars or from methane driving steam engines, with the methane also manufactured on Mars.

3. Create soil and grow food or plants to produce raw materials for clothing.

4. Construct buildings out of Mars bricks.

5.  Manufacture rocket fuel.

6. Fulfil your water needs.

Mars colonists can live very frugally. They want be requiring huge resource inputs for home furnishings, private automobiles or many sets of clothes.

Some of the key cargo requirements will probably be:

Medicines and medical equipment.

Rovers and other vehicles - although electric motors can probably be built on Mars from an early stage.

Replacement space suits.

I suppose you are correct.  Once they have raw materials for 3D printers and other manufacturing methods, electronic exports from Earth to Mars, will satisfy most needs.  I would think bringing in the equipment to be able to obtain those raw materials would be the extravagant part.

This ISRU thing also leads back to an orbit-based mission with multiple landers exploring multiple sites.  If you do that the first half of your stay at Mars,  you can find the site where your ISRU is most effective in terms of actual ground truth.  Remember,  ground truth has always been at variance with remote sensing,  everywhere we have ever sent probes. 

The second half of your stay is where you land everything and everybody at the "best" site (likely the one sitting on top of the buried glacier,  where you can mine water with hot water down a simple well).  Put your base complex there,  where it can succeed,  and either mothball it or leave it running on automatic when you leave.  I say that,  because I really do believe there will only be one government-sponsored mission to Mars.  It'll get cut off just like Apollo.  If the base is there,  visionaries like Musk will go back sooner. 

If you have an orbit-to-orbit vehicle that can keep a crew alive for the long transit,  why throw it away for the return?  That vehicle could take crews to any destination inside the main asteroid belt,  including the NEO's.  So,  re-use it.  Build and launch the one,  use it to visit the many places. 

We keep iterating back to that 1950's concept of a orbit-to-orbit ship(s) plus landers,  when we look at these issues from first principles,  unconstrained by who has been building what.  Because it has made sense for half a century now. 

I hope Musk builds his giant rocket.  Think $500/lb to LEO in 100 ton modules.  Not the $1000/lb with 50 ton modules to LEO with Falcon-Heavy.  Not the $2500/lb with the current commercial launchers in the 10-20 ton class to LEO. 

GW

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#67 2015-03-22 11:33:02

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 17,390

Re: 3D Printers

Here is another company using the printing to make an engine....by Aerojet Rocktdyne

3D printed components for AR1 rocket engine undergo hot-fire testing

AR1-Test-with-Additive-Manufacturing-Photo-1-647x480.jpg

According to Aerojet Rocketdyne, the AR1 is a 500,000 lbf (2.2 MN) thrust-class liquid oxygen/kerosene booster engine, one being developed to provide the US market with an additional rocket engine. With the political issues that surround the Russian-made RD-180, having domestically-produced engines is considered a requirement.

The injector was hot fire tested at pressures in excess of 2,000 psi (13.8 MPa), the company has stated that this represents the highest pressure hot-fire test conducted to date, especially one that was conducted during an exercise that the engine would encounter during an actual mission.

“Aerojet Rocketdyne is committed to delivering an RD-180 replacement by 2019, which is why the company is investing in the engine and inviting the Air Force, ULA, and other key stakeholders to all major reviews so that engine certification can occur in parallel,” added Cova. The company has made progress toward utilizing this technology to “print” rocket engines. Some milestones the company has met include the following:

Completion of System Requirements Review;

Full-scale single-element main injector hot-fire testing;
Subscale preburner testing;
Turbopump inducer testing.

The AR1 will serve as a backup for Blue Origin’s BE-4 rocket engine, which is planned for use on United Launch Alliance’s Next Generation Launch Vehicle or “NGLS”.

Aerojet-Rocketdyne-AR1-rocket-engine-image-credit-Aerojet-Rocketdyne.jpg

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#68 2015-04-19 20:06:30

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 17,390

Re: 3D Printers

We have seen plastic ,metals and now 3D Printed Lunar Building Block made from simulant...

ooLunar_building_block.jpg

Ya a 1.5 tonne building block with a printer that can build that large just send a unit to mars and have it make the habitat....

http://www.esa.int/Our_Activities/Space … D_printing

The UK’s Monolite supplied the D-Shape printer, with a mobile printing array of nozzles on a 6 m frame to spray a binding solution onto a sand-like building material.

3D ‘printouts’ are built up layer by layer – the company more typically uses its printer to create sculptures and is working on artificial coral reefs to help preserve beaches from energetic sea waves.

“First, we needed to mix the simulated lunar material with magnesium oxide. This turns it into ‘paper’ we can print with,” explained Monolite founder Enrico Dini. 

“Then for our structural ‘ink’ we apply a binding salt which converts material to a stone-like solid.

“Our current printer builds at a rate of around 2 m per hour, while our next-generation design should attain 3.5 m per hour, completing an entire building in a week.”

D-Shape_printer_node_full_image_2.jpg

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#69 2015-04-20 18:54:35

louis
Member
From: UK
Registered: 2008-03-24
Posts: 5,339

Re: 3D Printers

"the company more typically uses its printer to create sculptures" -

Mega-wealthy artists on Earth will pay millions to be the first artists to produce art on another world - guaranteeing themselves a place in history for all time.  Why wouldn't Damien Hirst pay say $50million to produce the first sculpture on Mars?   

You could build a replica on Earth and then destroy the software. Both could be sold on the market.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#70 2015-04-20 20:36:12

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 17,390

Re: 3D Printers

Could be part of that made in space companies items to sell once returned to Earth....

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#71 2016-01-07 20:13:28

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 17,390

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#72 2016-01-08 04:43:10

louis
Member
From: UK
Registered: 2008-03-24
Posts: 5,339

Re: 3D Printers

https://www.youtube.com/watch?v=5M_eDLyfzp8

This is an interesting video on producing bioplastics.  Looks like this is definitely something that could be produced on Mars, and no doubt the end product could be improved upon with the right machinery and expertise. The video mentions starch which is a combination of carbon, hydrogen and oxygen - all present on Mars.  By growing plants with starch on Mars, we don't have to do any of the complex chemical engineering involved in producing the basic constituents for plastics.

Presumably, then, bioplastic pellets could be used in conjunction with 3D printing to produce intricate items.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#73 2016-01-08 05:24:01

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 5,862
Website

Re: 3D Printers

Considering how bioplastic is made, isn't it biodegradable? That means it will rot. Some people obsess over biodegradable, but that's only applicable for disposable items. If you want plastic flatware that you use on a picnic once then throw away, this is a very good idea. But far better is stainless steel flatware that can be washed. Water and dish soap are far less energy intensive than making new plastic flatware for every meal.

Did a quick Google. Biodegradable has limits: The Truth About Bioplastics

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#74 2016-01-08 05:29:34

louis
Member
From: UK
Registered: 2008-03-24
Posts: 5,339

Re: 3D Printers

Energy intensity is not an issue for a small colony on Mars - per capita energy generation on Mars will be absolutely huge and the element required to produce plastic relatively small.

Your link says ordinary plastics biodegrade - so not sure what your point is.

I think the key issues are "usefulness" and "labour input".


RobertDyck wrote:

Considering how bioplastic is made, isn't it biodegradable? That means it will rot. Some people obsess over biodegradable, but that's only applicable for disposable items. If you want plastic flatware that you use on a picnic once then throw away, this is a very good idea. But far better is stainless steel flatware that can be washed. Water and dish soap are far less energy intensive than making new plastic flatware for every meal.

Did a quick Google. Biodegradable has limits: The Truth About Bioplastics


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#75 2016-01-08 05:38:28

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 5,862
Website

Re: 3D Printers

louis wrote:

Energy intensity is not an issue for a small colony on Mars - per capita energy generation on Mars will be absolutely huge and the element required to produce plastic relatively small.

Your link says ordinary plastics biodegrade - so not sure what your point is.

I think the key issues are "usefulness" and "labour input".

Ok, I'll accept that. "Labour input" is a good measure. My point is you want durable goods, not something disposable. The link also emphasized the distinction between biodegradable and compostable. In the 1990s, "biodegradable plastic" was normal petroleum plastic with some starch mixed in. The starch would decompose, but plastic didn't. Not useful. Bioplastic is compostable. But my point is it isn't durable, so you have to replace it. Bioplastic makes great flatware for a picnic or quick meal from a cart vendor on the street, but a Mars colony will want durable goods.

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