Z-pinning is a very interesting method to improve the strength of 3d printed parts across multiple layers. (i.e. make the parts strength more isotropic).
I assume this is most effective in solid 3d printed parts but I think this could have a positive effect on strength parts with thick enough walls as well.
The url below links to a research abstract on z-pinning for FFF manufacturing.
“The z-pinning process begins by printing a part in a conventional fashion that contains multiple voids in each layer that are intentionally aligned in the z-axis (Fig 1a). In the example shown, the voids are staggered in depth – one penetrating 6 layers deep, the other only 3 layers. Prior to deposition of the next layer, the print head is positioned over the deeper of the two holes and material is extruded until the void is filled (Fig 1b). The shallower of the two holes remains unfilled. Then the next 3 layers are conventionally printed, maintaining the aligned holes across layers (Fig 1c). The print head is then positioned over the deeper of the holes (different x-y location) and material is extruded in the z-direction to fill the void (Fig 1d). The process is repeated for the following 3 layers, allowing for deposition of a second pin into the same hole (x-y location) as the original pin (Fig 1e). Although this approach allows for deposition of continuous material across multiple layers, the z-pins have a finite length (6 layers in this example) which results in a “seam” at the interface between successive pins at a given location. The seam position can be varied among neighboring pins by staggering either the pin length or the starting layer of the pin.”
