Pathio Users

Variable Walls Thickness

Suggestion Summary

i’ve experimented with a technique that i’ve invented myself which i referred as variable walls thickness. the idea is to use finer layer height for the outmost perimeter and thicker layer height for inner walls. the slicer will print the finer layers first, once the finer layers is as thick as the thick layer, it will print the thicker layer as well. say a 0.1mm layer on the skin, 0.3mm layers on the inner walls, the slicer be printing the thickest walls in an interval, every 3 fine layers.

I’ve experimented by using Processes on s3d, load a model twice (basically two model), place the models at the same position which they will overlap eachother. the first model serves as the outershell (only 1 perimeter). the second model serves as the inner walls by applying horizontal offset to shrink the model in xy plane (since slicer is able to do 3d offsets, this will work even better).

The idea can also be combined with variable layer height technique to further increase surface details and shave print time.

Why is this useful?

no other slicers do this but you can hack this with horizontal offset and process on ideamaker and simply3d. it will create a detail shell on the skin layer but strong walls inside both reduce the print time and improve the print quality.

Screenshots/Supporting Info

Flaws/Challenges

the flaw is the finer layers and thicker layers will sometimes overlap with each other, but it can be solved by doing 2 tracks on the finer layers and/or having a gap between the outer and inner wall. however, with pathio, this is already the case, the inner walls can simply be “combined” into a single layer.

  1. a longer and pointier nozzle will work better as it can deal with overlapping slopes better.
  2. the challenge will be to figure out the collisions, this is usually not a problem if the slopes are not too steep.
  3. allow the user to specify the nozzle “angle” so that calculation can be done on the limits of the slopes - as per layer height differences.
10 Likes

Hi megablue,

That’s an interesting idea,

Could you attach your Gcode and some photos of a finished print so I can have a look into this?

Thanks!

Daniel

1 Like

the forum doesn’t allow me do attachment as a new user so I’ve uploaded the gcode to mega.nz

https://mega.nz/#!4pl3mSxK!2eX0CNBmifzL1hfIbG3DJrLyB8l1uXKbDQND1HxQF4M

I’ve made a mistake, the finer layers are actually 0.05mm layer height. and here are pictures of the thanos printed with this technique.

3 Likes

Neat idea!
Is this done by having a shell of the model and the infill as seperate files printed with different settings or is this using a script?

1 Like

no, i am “hacking” the slicer. the slicer is basically treating the shell and inner parts as 2 separated models in the same location. i’ve applied horizontal offset on the second model with 0.4mm(the line width) . i’ve explained in my first post.

although, this can be done with a script as well.

1 Like

Currently you can set infill to print thicker than the shell (“Print infill every number of layers”), Does that match what you’re thinking?

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not exactly. the idea is to use low layer height on the shell, but a higher layer height for the inner walls and infill to reduce print time. this screenshot might be easier to understand.

image

3 Likes

Got it. That does sound useful!

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Which process is done first?

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I’m guessing it would have to be the outer perimeter?

Daniel

1 Like

yes, outer first in most cases. i haven’t try inner first though (since it will require me to write a script to reorder the sequence). i think if there is an inward slope inner first will avoid issues of collision with previous tracks.

1 Like

I’ve been thinking of something similar for weeks.
But the idea would be to create progressively variable walls.
In the screenshot of the megablue, the wall jumps from the thickness of 0.05 direct to 0.3 and this can produce a series of problems, according to the illustrations that I did below.
Variable%20Walls%20Thickness%20-%2001

In the first image, using a 0.4 mm nozzle MK8, what is expected is that the impression occurs as represented, but where I highlighted in yellow, there would be a lack of adhesion between the walls in at least 2 layers of 0.05 for each layer of 0.3.

This would be the first problem. Now let’s consider the print order.

Variable%20Walls%20Thickness%20-%2002
At 2, the print starts at the wall of 0.3. when it changes to the 0.05 wall, the nozzle would collide with the anterior layer, no matter what the shape of the nozzle.

Variable%20Walls%20Thickness%20-%2003
At 3, the print starts at the wall of 0.05. Here there would not be the previous collision problem, but we would have the problem of building a very high 0.05 wall with 6 layers before we can start the wall of 0.3. The chances of this external wall failing are very high, especially if the part is tilted.

The suggestion would be a process with walls with progressive increase of thickness. So it could start with an outer wall of 0.05 and end with the inner wall or the infill of 0.3 mm, that depending on the size of the nozzle, of course.

Variable%20Walls%20Thickness%20-%2004

2 Likes

In a situation with a sloped wall, another problem that may occur are the gaps between walls of different thicknesses.

Variable%20Walls%20Thickness%20-%2005
Ideally, the thicknesses are always multiples of 2.
Note that in case 1, there is a large gap between the walls of 0.05 and 0.3.
The same occurs in case 2 between the walls of 0.2 and 0.3, since one is not twice the other. In addition, it generates an irregularity in the innermost wall.

2 Likes

At first glance this would make for an absolutely killer feature.
It would be interesting to do some calculations to see how much time this would actually save for some very basic models at different scales compared to doing the whole model at the lowest layer height.

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Also eyeing toolchanger applications this would be great to be able to have infill done with the supervolcano at ridiculous layer heights and nozzle sizes while moving towards reasonable nozzle sizes and very thin layers for the outer shell.

3 Likes

Is it possible at least to get scripting variable that could be used to detect wall layer?
If that will be implemented, community can test that idea via scripting.