New slicing software for the voxelfill process

New slicing software for the voxel fill process. © AIM3D

In order to enable the broad applicability of 3D-printed components, the phenomenon of inhomogeneous strengths must be fundamentally resolved. Using the 3D extrusion technology of the CEM process, Aim3D has developed a voxelfill strategy that overcomes these limitations and increases the cost-effectiveness of the CEM process. Voxelfill can also be used for multi-material components and is generally suitable for the material groups plastic, metal and ceramic for the construction of 3D components.

The two-stage voxel fill process at a glance

With the voxel fill approach, components are no longer built up exclusively layer by layer (i.e. 2.5-dimensionally), but are filled across layers by using so-called voxels as volume areas. As usual, the component contour is first created as a basic structure using one or more sheets of extruded material. Inside the component, a grid pattern is created that defines the boundaries of the volume elements to be filled, similar to cavities. This structure of the voxels to be filled resembles the honeycombs in a beehive.

Filling of the voxels is staggered

The voxel fill strategy now consists of two process steps: 1. generation of a grid structure: The CEM system repeats this structure up to a defined height of the volume elements, until the previously generated cavities (voxels) are filled at this point by injecting the thermoplastic material through the extruder. 2nd filling phase of the voxels: Now the second, even more important component of this 3D printing strategy comes into play: when filling the volume areas, not all voxels are filled in one plane. This would again result in a weak point in the Z direction in the "seam" plane. By offsetting the volume elements halfway up the voxels, a kind of "brick bond" is created in the component.

The Exam 510 3D printer. © AIM3D

The fracture line is therefore forcibly offset. This results in an enormous increase in strength and also improves the elasticity of the components in the Z-direction. In addition, the introduced volume elements reduce the printing time for fully filled components enormously and thus significantly increase the cost-effectiveness of the CEM process.

Outlook on the potential of Voxelfill

Variations of the voxel fill strategy using the CEM process enable the use of different materials: hybrid multi-material solutions with different voxel fill materials and construction materials for the contour/structure of the inner walls are possible. In this way, the material properties can be "customized". Component weight, damping properties, center of gravity manipulations or elasticities can be defined, tailored to the application, and the component properties can be specifically influenced by selectively filling only certain volume chambers (selective densities) on the basis of FE simulations. Voxelfill makes it possible to fill only those areas of a component that are absolutely necessary for the flow of forces. As a result, these components look like "classic" components from the outside, with all the advantages for post-processing. At the same time, however, 3D printing reduces the amount of material and weight, including lightweight construction.

Targeted alignment of fibers for optimum mechanical properties

Especially when using fiber-reinforced materials, the use of voxel fill provides an additional option for specifically aligning the fibers in the component in order to increase the mechanical properties. In the voxel fill strategy, this concerns the contour and the inner walls of the component. By injecting the material into the volume chambers (filling the voxels), the 3D component also receives fibers that are aligned in the Z-axis, thereby further improving the mechanical properties.

Clemens Lieberwirth, CTO at Aim3D: "The voxel fill process is of course particularly suitable for 3D printing of plastics and fiber-filled plastics, but is also suitable for 3D printing of metal and ceramic components using the CEM process. In general, there are advantages due to the higher build speed and cross-layer filling."