[HN Gopher] Show HN: 3D printing giant things with a Python jigs...
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Show HN: 3D printing giant things with a Python jigsaw generator
Author : naggie
Score : 163 points
Date : 2025-01-23 13:35 UTC (4 days ago)
(HTM) web link (calbryant.uk)
(TXT) w3m dump (calbryant.uk)
| ramboldio wrote:
| A big advantage of this technique is that the assembled model is
| 'isotropic'. If it was printed in one piece, it would be easy to
| split along the layer lines.
|
| But when printing the plates separately, every face is equally
| strong.
|
| Great project!
| nine_k wrote:
| This is cool. This is also massive. I wonder how much e.g. the
| arcade machine housing costs just in the filament used, and how
| many hours did it take to print.
| regularfry wrote:
| There's a relatively well-travelled path of filling hollow
| prints with something to get strength back, which does mitigate
| that. What that something is will vary per application, but
| I've previously used premixed post-hole concrete where I've
| just wanted to add weight.
| almog wrote:
| > "The strength comes from the tightening/wedging effect when
| pulling the join apart. If the dovetail is tapered, the join can
| also tighten when it aligns too - this is highly desirable for
| gluing, as it means the glue will not be scraped away."
|
| While true, dovetail and other traditional woodworking joints
| borrow their strength from using the wood grain to support the
| joint.
|
| I don't know a lot about 3D printing but I'm guessing a lot of
| the assumptions about woodworking joints strength aren't
| applicable.
| bb88 wrote:
| Interesting. I didn't know that.
|
| But I do know about 3d printering. :)
|
| Strength in printing is usually a function of the mass used to
| print with. So more plastic used at the boundary layers will
| mean stronger joints.
|
| Eg. A PET plastic soda bottle (pepsi, coke) will flex in the
| body where it's thin, but not on the threads on the top of the
| bottle. In fact, those are pretty strong, because they need to
| hold on a cap which keeps the carbonation in.
|
| A good question to ask is if the dovetail joint in plastic as
| strong as wood? The answer may likely be no, but it may not
| also need to be. It just needs to be "good enough". And this
| looks like it might be.
| wongarsu wrote:
| Grain direction in woodworking has many similarities to layer
| lines in 3d printing. That makes techniques from woodworking
| often more directly transferable than techniques from CNC
| machined, cast, or injection molded parts.
| almog wrote:
| How so? What kind of filament preserves a multiple fibers
| like structure that resembles wood grain? Sincerely asking
| since I couldn't find any source for that
| WillAdams wrote:
| layer lines.
|
| That said, if the part is small, and one can afford to
| print w/ 100% infill just put it in a tray of salt and bake
| to re-melt/re-flow to make a (more) solid part.
|
| https://x3d.com.au/blogs/tips-and-tricks/pla-baking-the-
| secr...
| almog wrote:
| Wood strength is high with the direction of the grain and
| weak across the grain, is that a property of layer lines
| too? I just couldn't find any source that claim it to be
| so.
| WillAdams wrote:
| See:
|
| https://xometry.pro/en-eu/articles/3d-printing-strong-
| parts/
| wongarsu wrote:
| Each continuous strand of filament is kind of like a wood
| fiber, in the sense that the strand is much stronger than
| the connection to the other strands.
|
| Of course 3d printers lay these strands in a 2d plane (and
| stack layers of these 2d planes), whereas trees grow in
| more-or-less one dimension. So wood has one strong
| direction and two weak ones, while 3d prints have two
| strong directions and one weak direction. And obviously 3d
| printed strands are layed out by boring and often naive
| algorithms that lack any of the beauty of naturally grown
| wood. Then again, for structural applications you also want
| the most bland and boring wood patterns possible.
| almog wrote:
| That much I'm aware of, but as I mentioned in previous
| comments, with wood strength is high in the direction of
| the grain but weak across the grain, plenty of academic
| studies confirm that (and it takes little to verify it
| empirically).
|
| With 3D printing, despite the analogy, I couldn't find
| any sources for strength along/across the "grain" so i'm
| not sure how accurate that analogy really is.
| wongarsu wrote:
| With 3d prints this is usually framed as layer adhesion.
| Within one layer (so in the x-y plane) you are basically
| "along the grain" since the strands form loops and other
| 2d shapes within the layer. Between layers (== in z
| direction) you only have the adhesion between different
| strands holding the layers together, which is equivalent
| to going across the grain in wood.
|
| CNC kitchen on youtube does a lot of strength and impact
| testing, e.g. [1] (results at 9:55). "Across the grain"
| you have half the strength in PLA (and similar numbers in
| all filament types except TPU). Or if you prefer
| manufacturer numbers, [2] is the datasheet for a random
| PLA filament. It also shows worse numbers in every metric
| in the Z direction (across the grain).
|
| The difference isn't as severe as in wood, but it's big
| enough that it is something you have to consider in
| structural parts
|
| [1] https://youtu.be/dOzVuoBP9gY?t=535
|
| [2] https://polymaker.com/wp-content/uploads/lana-
| downloads/Poly...
| observationist wrote:
| https://github.com/TengerTechnologies/Bricklayers
|
| This came at a perfect time, then - you can cause each adjacent
| layer to be offset by half the layer height, to maximize the
| strength.
|
| Annealing parts by baking them at the right temperature for a
| sufficient length of time is relatively easy to do. Printing at
| higher temperatures and slower speeds to ensure layers are
| melted together also results in higher strength parts.
| nejsjsjsbsb wrote:
| I been thinking an openscad->cura pipeline would be cool. This
| post is very similar and inspiring.
|
| Imagine running a custom action or pipeline and getting a
| physical object pop out in the shed. Pretty awesome.
|
| I also like the idea as git as the way to share and remix 3d
| printing instead of (as well as) the various STL sites.
| bb88 wrote:
| I kinda want this in the slicer, like prusaslicer.
| lucasoshiro wrote:
| I once tried to do something like that, but I stopped when
| trying to deal with the CuraEngine CLI...
|
| I don't know if other slicers have a better CLI, or even if
| they have a CLI...
| wongarsu wrote:
| Orca Slicer might be a good candidate. The cli is a bit
| rudimentary. I assume it was built by Bambu Labs for slicing
| ready-made print profiles for printing from the mobile app.
| Or maybe it's inherited from PrusaSlicer (Orca Slicer is the
| open-source fork of Bambu Studio, which was forked from
| PrusaSlicer, which was forked from Slic3r). But as long as
| you only want to apply print settings, filament settings,
| load an stl, run auto-layout and get gcode out, it should do
| the trick with minimal effort.
| Joel_Mckay wrote:
| Keep in mind some OpenSCAD designs use complex library
| dependencies, and baked source geometry.
|
| The simple language IDE preview pane sometimes chokes on the
| surfaces that are compiled, and on rare occasion must be done
| via command line. Thus, some complex designs may take hours to
| generate a model.
|
| The slicers are meant to be more CAM tool than CAD utility, but
| people are mixing features as use-cases increase in complexity.
|
| Best of luck, =3
| ajolly wrote:
| You can link openscad to a slicer, at least in the dev
| snapshots, press F8 and your model opens in your slicer of
| choice.
|
| Makerworlds customizer is simply a web version of OpenScad.
| Upload your OpenSCAD script and good to go
| CharlesW wrote:
| A linked-to inspiration for this -- printing an arcade cabinet
| for Atari's Space Race (1973) -- is a great watch too:
| https://www.youtube.com/watch?v=SONO6LTHuR8
| DonHopkins wrote:
| Oh man, now I totally want to 3d print a full sized interlocking
| Han Solo in Carbonite with embedded magnets to stick on the front
| of my refrigerator!
|
| Maybe I'll have to get huge commercial refrigerator for the
| proper effect, but it will be worth it.
|
| 3d printed life size Han Solo in Carbonite replica Part 1:
|
| https://www.youtube.com/watch?v=lOj3yZ-iMjM
| lucasoshiro wrote:
| I'm really happy to see OpenSCAD stuff here in HN. Of course it
| has some downsides (not being able to measure an object is the
| main one...), but it is an underrated tool.
|
| I'm using it as my main 3D modeling tool for three years, and I
| even gave I course about it last year. No regrets, and I never
| felt that I needed to learn Fusion or similar
| Joel_Mckay wrote:
| Depends on the use-case, but openscad can be useful for simple
| parametric designs prone to deformation during manufacturing
| (we use it for printing off-axis parabolas.)
|
| FreeCAD supports the openscad language plugin, and can generate
| proper solids. Many classic CAD/CAM users often see the
| parametric design workflow as baffling... not an entirely
| undeserved reputation.
|
| Freecad tutorials:
|
| https://www.youtube.com/@4axisprinting/videos
|
| Blender geometry nodes tutorials:
|
| https://www.youtube.com/@Entagma/videos
|
| Best of luck, =3
| GuB-42 wrote:
| For me, the big problem with OpenSCAD and the reason I let go
| of it quickly is the lack of constraint-based modeling. For
| example, if I want to design a cup and I want my handle to have
| a 30mm round hole that is tangent to the walls of the cup, I
| want to be able to adjust the thickness of the handle and the
| size and shape of the cup while keeping these properties. And I
| don't what do do the maths myself if I can avoid it.
|
| OpenSCAD does very little to help me with these maths as it
| doesn't have a solver. Not to my knowledge at least.
| WillAdams wrote:
| Basically one has to write the solver oneself --- see comment
| elsethread about how this is OpenSCAD's weakness --- what one
| can make in it is bounded by one's mathematical fluency.
| zokier wrote:
| Other big problem is one demonstrated also by the article;
| openscad is not great at any rounded shapes because it is
| mostly polygon based. So even if you write out the maths
| explicitly they might end up being wrong because of the
| difference between true round and the polygonal approximation
| WillAdams wrote:
| OpenSCAD recently got a Measure tool:
|
| https://www.youtube.com/watch?v=Q_AEHI2o-6Q
|
| OpenSCAD's strength --- that it makes it easy to create 3D
| designs which are easily represented mathematically using
| cubes, spheres, cylinders, cones, and assemblies and
| distortions thereof is also its weakness --- what one can do in
| OpenSCAD is strongly bounded by one's fluency in
| mathematics/geometry/trigonometry (says the guy who is stuck on
| conic sections in a particular project and needs a solution
| which is faster to calculate).
|
| Still waiting for the Python-enabled version to make it big:
|
| https://pythonscad.org/
| kiba wrote:
| Being able to do object oriented programming is going to make
| reasoning about geometrical objects much easier.
|
| I like the measuring tool but I prefer doing something more
| permanent like labeling it.
| camel_gopher wrote:
| I 3d printed puzzle pieces using Go to generate the join
| sections. Figuring out the right tolerance takes some trial and
| error.
| tda wrote:
| In similar vain, but the with cadquery and Jupyter notebook is
| the screwdriver stand I once made:
|
| https://github.com/tdamsma/Screwdriver-rack
| ashoeafoot wrote:
| Skipping teeth? Why not scale the whole series of dove tails for
| detected cases?
| WillAdams wrote:
| That requires re-working the design for the fit tolerance.
| ashoeafoot wrote:
| only the dove tail scaled should work
| batch12 wrote:
| I wonder if leaving some of the base intact would help with the
| artifact issue. Instead of cutting the teeth all the way through
| the whole section, leave a few mm solid on each side and reduce
| the height of the teeth to compensate the opposing base layer. It
| might add a bonus of hiding the teeth, too.
| jgoewert wrote:
| This came up at pretty much the perfect time for me to try out.
|
| I started learning OpenSCAD over the weekend to try out an idea
| to 3d print a 70" dome to make my own Star Wars Battlepod after
| seeing that video on making the replica Space War cabinet.
|
| One guy got an acrylic forming shop to make him one about 10
| years ago for $700, but I was calculating in how much it would
| cost to 3d print and stich a dome screen together. My test sample
| that I started used a sort of ribbed dome that I was trying to
| figure out how to split the file and bolt it together -
| https://www.reddit.com/r/openscad/comments/1i922ed/trying_to...
|
| I started playing around with thickness because at 1/2 inch, it
| was looking like about $200 in filament. But if I can reduce the
| thickness because of having the jigsaw edging to make it easier
| to align, it might get cheaper.
|
| Currently tried running this in Windows and it isn't happy. I'll
| make a Linux VM and give it a go again.
|
| >>WARNING: Too many unnamed arguments supplied in file in.scad,
| line 6 Geometries in cache: 20 Geometry cache size in bytes:
| 3802608 CGAL Polyhedrons in cache: 182 CGAL cache size in bytes:
| 0 Total rendering time: 0:00:01.063 Top level object is a 3D
| object (manifold): Status: NoError Genus: 1 Vertices: 39078
| Facets: 78156 Num. beds: 0
| ajolly wrote:
| This is great I'm going to have to try this out. I've got my own
| openscad dovetail joint scripts, but this seems more refined.
| MisterTea wrote:
| While this is nice for things like the speaker enclosure I cant
| help but recoil in horror from the 3d printed arcade cabinet - so
| much plastic. I get how this enables shapes and other niceties
| but between aesthetic and the environment I'll take boring and
| recyclable any day.
| WillAdams wrote:
| Aren't 3D printer filaments recyclable?
|
| I know that at least one person doing 3D printing was making it
| a point of picking up old projection TVs and recycling the ABS
| housing to make new filament using a Filastruder.
| MisterTea wrote:
| You can mostly recycle ABS but unsure of the others. In the
| case of ABS Plastic it isn't infinity recyclable and you can
| get maybe 2 or 3 uses from it before it degrades. Personally,
| I would prefer we design for minimizing plastics.
| SSilver2k2 wrote:
| Take a look at Luban3D. It does a lot of the automated mesh
| cutting.
|
| https://www.luban3d.com/
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