3d Printers use 2d technology... why?

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#1

The more I have been looking into 3D printing, the more ironic it seems: the printing of 3D objects relies on slicing a 3D shape back into 2D sections to be layered back up again to form a 3D model.

You can get pens to physically draw in 3D space, you get lego robotic arms; its not a massive leap to a technology that actually prints in 3D. Even using a shaped base plate or one that can be angled/moved as the object is being created. Putting sensors on it to keep the perfect balance as it’s being formed shouldn’t be a technological mystery.

I’m sure that they will evolve, but it seems to me that there are more solutions to fix the symptoms rather than looking at the cause.

#2

Well, i think it is because of how our world is made.

You start from 1D to 2D, then 3D.
You start from lines, faces, then solids(volume).

Technically, 3D printers use 1D and 2D technology.
The pens you talk about are essentially 2D, because they are constructed with lines? :smiley:

We are talking a bit of philosophy here.
Anyone care to join?

#3

creating material in the emptiness could be difficult, having a moving/rotating base plate is surely more difficult to control than a base moving in the z axis only and therefore expensive and probably less exact.

#4

There are some cases in the 3D printing world where the image goes from 3D data to the final results.

#5

I agree with @josephkim626, can you think of anything that we as humans build that really works differently? The only thing I can think of that doesn’t really get created in roughly 2D layers are some living things! I don’t think we’re going to get to creating life from scratch any time soon, if ever, but that is certainly a different thread.

That aside, creating non-2D layers has been the subject of some work and they have done it. The issue is creating a tool path that doesn’t get in the way of itself, which is why cartesian bots are still the most popular and best refined, because it’s relatively easy to keep from hitting your previous work with the extruder, so it is the easiest tool path to create. At best right now is a way to print convex and concave surfaces. 6DOF (degrees of freedom) extruders have been designed, but a practical use has not been found to spur much prototyping as far as I’ve seen.

[quote=“gadget2020, post:1, topic:16067”]
it seems to me that there are more solutions to fix the symptoms rather than looking at the cause.
[/quote] I think you are mainly referring to things dealing with gravity, like supports, when you say this, but I’m not entirely sure, please correct me. If that is what you are talking about, SLA and SLS printers do a fairly good job of negating the effects of gravity, with SLS being the best. The only problem with SLS is that it’s still under patent, and quite expensive for the machines right now.

Please don’t take this as disparaging, because that’s not my intent; I really want to help. I’ve always tried to teach that the best solutions, are amazing because of the way they work with the limitations, not how they avoid them. When you spend some time looking through Youmagine and Thingiverse, you begin to see how amazing some of the designs really are.

I think the same goes for some of the other CNC fabrication methods that are becoming popular now as well, like CNC routers and laser cutters. Anyway, just keep designing, technology will catch up eventually!

#6

This is reminiscent of 3D sketching in SketchUp:

#7

We have segways, self-balancing 2 wheeled boards, cars with automatic suspension adjustment, drones with self-leveling and precise 3D spacial awareness… having a plate that can move and use gravity rather than use a secondary material to defy gravity must be a viable enhancement.

[quote=“jesse_s, post:5, topic:16067”]
can you think of anything that we as humans build that really works differently?
[/quote] yes - origami. I watched a TED talk recently where they have a program that can take any shape and work out the folds to turn a single sheet of paper into that model… it’s rather impressive.

Steel construction eg of bridges. Car assembly. Furniture making. Tailoring. Most creation of real world objects (before 3D printers) involves creating a supporting skeleton and then adding a skin to it. To me, that’s where 3D printing should evolve towards; 3D scanners and imaging can create good skins that are formed from going all around a subject; Why can’t the process be reversed and a skin be applied all round a skeleton?

[quote=“jesse_s, post:5, topic:16067”]
I’ve always tried to teach that the best solutions, are amazing because of the way they work with the limitations, not how they avoid them.[/quote]
And I always try and ask why are there limitations? The current generation of 3D printers have been designed by a generation of people who work from plans and drawings. The next generation will work from models and virtual reality.

Is the next step in 3D printing to be applying an ink/surface finish to a newly printed model? I’ve seen impressive liquid baths where an image is printed on the surface and an object dipped to transfer the image, but could inkjet printer technology be applied to put images onto the model? Could the model be manipulated under the printer head rather than the printer head moved about the model? I think that we need to see better creation of surfaces before we can apply a decent finish to them.

Another TED talk I watched recently was about “growing” a model out of gloop (https://www.youtube.com/watch?v=ihR9SX7dgRo) - and I still think that if the base plate could be manipulated to “grow” faces on the flat rather than edge on, it would see a great improvement in both speed and stability of the resulting model.

#8

First, yes, placing the entire printer in a 3DOF setup that would allow it to always use gravity to hold the filament straight would cover some aspects of reducing the need for support, but the greatest requirement is the ability to keep the extruder nozzle out of the way of different parts of the structure, that part is a terribly difficult set of calculations, reminds me of the shortest trip problem in Statistics :confounded:. The difference between 3D printing and all of the aforementioned inertial navigation systems is that precision is quite relative. A typical 3D Printer shoots for around .01mm accuracy for the tool placement for the duration of the print. That is improbable with an inertial navigation system. A drone has the ability to correct it’s position via checking it’s inertial navigation system against GPS, there’s not really anything accurate enough right now to allow you to do that on a 3D printer size scale. I imagine something like a 3D scanner guided 3D print head, and the costs start to skyrocket, LOL.

[quote=“gadget2020, post:7, topic:16067”]
Why can’t the process be reversed and a skin be applied all round a skeleton?
[/quote]It could, if we could get the tool extruding the material into the areas required to make the skeleton. On a typical construction site, there are many “tools” at work(I’ve met them :stuck_out_tongue_winking_eye: ) and all are smaller than the resulting structure. On the flip side, there are only one or two tools on a 3D printer, and they are much larger in relation to the material they are laying.

[quote=“gadget2020, post:7, topic:16067”]
Is the next step in 3D printing to be applying an ink/surface finish to a newly printed model?
[/quote]They have some powdered SLS like printers that spray a colored or clear glue to adhere layers of powder to form a model, on example is here. It would print without support as well.

[quote=“gadget2020, post:7, topic:16067”]
I watched a TED talk recently where they have a program that can take any shape and work out the folds to turn a single sheet of paper into that model… it’s rather impressive.
[/quote]Was the software open source? Sounds cool. I would like to have the ability to do that with sheet metal.

#9

This is a 1-dimensional action (although when you map this 1-dimensional subspace into the 3D space it makes use of all three coordinates).

As long as we don’t have a 3D printer that pops out an object on the press of a button, we need to serialize an object into a sequence (~ 1 dimension) of operations that one or several tools can follow over time (which is also 1-dimensional).

How this sequence of operations is realized (or how the tool path looks like) is a matter of implementation, and other requirements that for example every interim state (unfinished object) must follow laws of physics and must have certain stability etc.

#10

BTW, is pointcloud modeling 1D or 3D modeling? its debaitable :smiley:

Google Pointcloud <- Link!

#11

This is the origami link: https://www.ted.com/talks/robert_lang_folds_way_new_origami?language=en (http://www.langorigami.com/) it’s a few years old now, but the principle is the same.

Latest technology; https://www.newscientist.com/article/dn24275-3d-printed-objects-outgrow-their-printers/

And if you wanted to assemble your own slices for a 3D model there is this; http://glowforge.com/

[quote=“josephkim626, post:10, topic:16067”]
BTW, is pointcloud modeling 1D or 3D modeling? its debaitable
[/quote]each point in the cloud has an x,y and z cordinate; how can it be anything but 3D?

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#12

Each 2D sections on the 3D prints have x,y and z coordinates; how can it be anything but 3D?

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#13

Good links! I’m in class today, so I didn’t watch the video of the TED Talk, but I will. The second link is cool, and they’re using a SLA printer to do that. I really like the GlowForge auto-focusing laser, that’s awesome (don’t know if I would trust any laser cutter with the lid of my MacBook though :grimacing:). Love the wood and leather products, I’m hoping to start playing with the Laser Cutters at my local makerspace soon.

#14

As has been said, 3d printing IS currently 3d.
0d = a dot at [0,0,0]
0d/1d = a dot in space where it’s [0,0,0], or ONE x/y/z value is set.
1d/2d = a dot in 3d space [x,y,z]
2d/3d = a line where z==z [x1,y1,z] & [x2,y2,z] >> today’s 3d-printing - because its z increments with each ‘level’ of ‘z’.
3d = a line [or lines] where z!=z >> what you envisage - changing the z for every vertex of every line !!!
A 3d-aware printing head is obviously programmable, BUT the algorithms needed to avoid clashed of ‘lines’ in 3d could be a zillion times more complex than simply slicing the object in to tiny horizontal slivers…

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#15

Sigh! It is too easy to make glib statements about what should be possible if you don’t have to design and build it yourself! As a former engineer, it strikes me that there are some serious technical challenges needed to get to where gadget2020 wants to be; it isn’t as if something like this can be rolled right off the shelf. Current “3D” printing relies on building up 2D layers because the technology required (both hardware and software) to do so was within reach and affordable. In contrast, 6DOF milling machines are very expensive and often treated as not-for-export military technology because they are hard to make and use!

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#16

the first 3d printer I ever saw was at Rover back in the day…

it fused liquid resign held in a tank, starting in the centre and working outwards to the objects extremes.

from memory it used two low power lasers, but it may have been three…

it was making a new manifold for a Rover V8 at the time I saw it…

john

#17

3D printing is still based on 2D because the material is lain down on a 2D plane; x and y. You move the z coordinate and then do the 2D thing again: it’s 2D+1. True 3D would be forming faces and planes based on the best way to keep structural integrity, not limited by having to be sliced into horizontal strips.

What I would really like to see is the mass of a model made into a “low poly-count” shape that could be (automatically) assembled from a sheet of material that would be cut/folded/joined to make a basic structural skeleton. This would then be used to ‘print’ the high poly count model on top of with each of the low rez skeletal facets being rotated to form a new ‘base plate’.

Yes it’s complex, but why should that be a barrier to stop reaching for the end goal? There are some very clever people out there and some very clever technology. You can buy a 3D printer for $349 (https://printm3d.com/themicro/) It’s so readily available and becoming so affordable that it won’t be long before some “garage innovator” is doing things with the tech that we can’t even imagine.

#18

Some people do that by hand, creating a skeleton, which could be done via laser cutting or CNC milling from structural material, and then 3d printing the “skin” and attaching it in some way, so that’s does work. Again, I’m not sure how much that could be turned over to a machine if you simply gave it a “solid” and told it to “make it structural”, I think that’s why we have en-guh-neers.

It’s more of an issue of possible vs. worth it. It’s a trade-off. And quite frankly, I’m glad there is still a need for design and engineering to be done by humans. Otherwise, capitalists would make ALL the money, LOL.

#19

Very interesting discussion but let me throw in something that would not require any hardware updates just software.
Thinking of FDM printers, why not dump the idea of the slicer and replace it with a “render engine”? Just have the print head move in 3d like a CNC router instead of 2d slices. Yes you would be limited to how far this could be taken by head bump but it could still make prints much stronger and much smoother.

#20

They have some folks that have worked on it, but the best extruders for that type of printing still typically only allow 20 degrees of angle from the print bed before you start bumping.

Really, in the long run, the limitations on FDM aren’t that big of a deal, after you get used to designing for it. And as more versatile filaments are refined for FDM, the capabilities get broader. I don’t think it’s that much more difficult than mastering good SketchUp model organization, just takes a little work and a little forethought.