Pathio Users

Vertically Interleaved layers in perimeters

A common weakness in FFF prints is that layer boundaries can be prone to delamination and fail sooner than in other directions.

A potential strategy to improve layer bonding can be to interleave the tracks in perimeters so not every track starts at even layer heights but insted we aim to get every other track to start at half layer heights.

The trivial example by which we can illustrate this is a vertical wall If you start by laying down a half height layer for even numbered perimeters, then raise the tool and lay down full height odd numbered perimeters, then full height even number perimeters until finally you lay down a half height layer on even perimeters again. This way every other perimeter is interleaved vertically eliminating the layer separation weakness.

This strategy is of course complicated once we depart from the trivial vertical example, so in practice it can likely only be done opportunistically as long as the vertical wall angle is close to vertical or close to 45 degrees, but for a lot of functional prints this would cover a lot of cases.

image

2 Likes

Another approach, which I have been thinking about for a while, is to create a stacked, porous mesh and then fill the multi-layer mesh “holes” with molten plastic, forming vertical columns. An optimal mesh would be one where the bottom of the void to be filled was larger than the levels above it (think of undercutting, the way a dentist drills out a cavity in a tooth prior to filling it). This would potentially increase the strength of the interlayer bonds to be greater than the pullout force of a strictly smooth column. The result is meshes stitched together with dumbbell shaped vias. I think there is a patent here :grinning:

I just realized that this idea is really for how to truly 3d print a fill (vs our current layered 2d approach to printing) , not a perimeter.

2 Likes

I really like this idea at face value anyway.

I think with the method you are proposing, you will have issues with warping, since you’ll be adding a a large thermal mass to an already cooled area.

Interesting. I just realized that this could be tested out with a 3d pen!

I really like this idea too, and it’s not new.

Effect of layer interleave on layer bonding has been tested some years ago with really good result:
http://pleasantsoftware.com/developer/3d/2010/12/08/the-rack/