Strenghtening FDM prints has been discussed in detail over the last years. Solutions and results vary as each one’s desires differ. Now [TenTech] shares his latest improvements on his post-processing script that he first created around January. This script literally bends your G-code to its will – using non-planar, interlocking sine wave deformations in both infill and walls. It’s now open-source, and plugs right into your slicer of choice: PrusaSlicer, OrcaSlicer, or Bambu Studio. If you’re into pushing your print strength past the limits of layer adhesion, but his former solution wasn’t quite the fit for your printer, try this improvement.
Traditional Fused Deposition Modeling (FDM) prints break along layer lines. What makes this script exciting is that it lets you introduce alternating sine wave paths between wall loops, removing clean break points and encouraging interlayer grip. Think of it as organic layer interlocking – without switching to resin or fiber reinforcement. You can tweak amplitude, frequency, and direction per feature. In fact, the deformation even fades between solid layers, allowing smoother transitions. Structural tinkering at its finest, not just a cosmetic gimmick.
This thing comes without needing a custom slicer. No firmware mods. Just Python, a little G-code, and a lot of curious minds. [TenTech] is still looking for real-world strength tests, so if you’ve got a test rig and some engineering curiosity, this is your call to arms.
The script can be found in his Github. View his full video here , get the script and let us know your mileage!
wow, that’s thinking outside the box!
I’m very excited to see this continue to develop.
You may want to point out a bit more prominently, since it’s buried in the README, that even though this can be run in Bambu Studio it does not support Bambu printers.
i have the impression people who use ABS feel differently but my general feeling is that “Traditional Fused Deposition Modeling (FDM) prints break along layer lines” is more a vibe — regurgitated received wisdom — than a reported reality.
everything i ever printed in PLA broke after 1-10 years due to PLA’s monotonically increasing brittleness over time (except things i printed fairly recently, which i know will break ‘soon’) — it’s rare to see something delaminate that hasn’t become fantastically weak ‘with the grain’ as well. i would never say “my prints break along layer lines”, because that’s not been my observed reality. but my prints do break!
i prefer not to carry force across layer lines, just like i prefer not to carry force in the plastic itself at all. but when i do, i find it’s surprisingly strong. that feeling of surprise is why i find this a reasonable building material — i have low expectations. if i had high expectations — like the people trying to 3d print large things without using bolts and extrusions and plywood to form the bulky or stressed components — then i would find it totally useless.
i just wish when i read that sentence that the image in my head was of someone talking about the pile of broken parts they’ve produced. and for all i know, that is the reality for this article. but instead it feels like an old wives’ tale, an unexamined orthodoxy. and now we’re getting nearly-daily articles about fairly poor ‘solutions’ to this everybody-knows-it’s-a-problem.
i’d love to hear in the comments here from others…what causes your prints to fail in your real life?
So basically, you do actually believe that inter-layer strength is intrinsically lower than in the other directions (not that belief is needed, the experimental data shows this explicitly.) Nobody said that means it’ll invariably break in that direction.
pfew you want me to rewrite my comment again but i already wrote it once
confidently wrong is still wrong
I print things that are mainly walls – enclosures you might say. And when they fail, it’s invariably “along the grain” – the layer lines. Maybe making the layer lines non-straight will help here. Overlapping alternate sine waves will also probably help.
I wonder if I can use this technique on my existing slicer and cheapo printer.
i appreciate your report, though maybe you should say what filament you’re using :)
i do a lot of enclosures and stuff like that and i only kinda sorta see them breaking along layer lines. for example, ye olde basic prismatic box with 1mm walls printed in PLA, hung on the back of my backpack. it did fail at a layer line, but specifically the one where the wall met the floor — so it’s not the layer adhesion that killed it but rather the corner. and even that break ‘along the layer line’ was different layer lines! it didn’t let go at one layer interface, it spread that failure along several interface by breaking the layer itself — the layer interface couldn’t fail until layers had failed internally as well. and then once i started inspecting it, i found that it had also failed orthogonal to that layer line, at the vertical corners.
and here’s the critical part that makes me throw away the whole poor-layer-adhesion mythos, is that it’s held onto my backpack entirely by layer adhesion across a 5mm x 8mm rectangle printed onto the top of the thing, and that didn’t fail despite receiving abundant abuse. i had agonized over that because i believed the received wisdom about layer adhesion, but that component has never failed in any way and i’ve printed several variations of this design.
so my decision to use a brittle material with only 1mm thickness without gussets killed it at a corner, and perfect layer adhesion would have infinitesimally improved the outcome. and the real killer thing is, even though the plastic was cracking up, it actually suffered an electronic failure and this was just a pointless post mortem of plastic that was, in fact, still enclosing the broken electronics adequately.
Sounds like a stress concentration point to me. More of the fault of the geometry than the process.
Add a nice filet there and it would probably help a lot.
Greater weakness of FDM prints in the Z direction has been directly measured, it’s not a matter of folk wisdom. Go watch any CNC kitchen video where he does strength measures, Z direction strength and toughness is a fraction of XY. The best you can do is print hot and slow (see printing glass settings), which still only achieves ~80% of XY strength.
It is well known and proven that 3D printed parts are significantly weaker in the Z direction for pretty much all filaments so how is it an old wives tail that parts often fail in that way? Parts failing in their weakest direction should be expected.
Just look at some in depth testing videos, like from My Tech Fun, he clearly shows the break surfaces and you can see quite often that parts break along the layer lines. See the difference between horizontally and vertically printed test samples, both in strength and the break surfaces.
In my own experience parts do break along the layer lines more often than in other direction, most failures are the result of delamination rather than breaks within a layer. That is why print orientation matters.
If you think about what is actually weak in the Z direction, the adhesion between layers not the layers themselves then that is the obvious point it would fail. Yes all the failures may not take place on the same layer but they tend to all be between layers.
Layer adhesion also applies somewhat within a layer because you are just laying lines of filament next to each other, they aren’t part of the same continuous piece of plastic.