Mastering Lattice Structures for 3D Printing: Design, Optimization, and Generation

Due to the complexity of lattice structures, it is impractical to model them into the part using typical CAD tools. In most cases, the part is drawn in CAD as if it were solid. Then, after the part has been designed (with DFAM principles in mind) the model is imported into another software package to generate a lattice structure. Among the more common programs for this purpose are Netfabb or nTopology. 

Another method of generating a 3D printed lattice structure is through generative design. In this case, a part’s connection points, mass limitations, and expected loads are defined. An algorithm then generates hundreds of solutions that would meet the requirements. From there, the most optimal lattice cell structure and cell density can be selected from among the solutions or generated through further iteration. When creating a lattice structure, it’s important to understand what factors will affect the overall function of the final part. These factors are listed below:

• Lattice Material: When 3D printing in metal, the lattice is often the same material as the overall part. However, if a flexible lattice is required then multi-material parts can be considered. Some products use soft flexible materials for the lattice and more resilient material as a shell to protect the lattice. One common example of this is a running shoe sole.
• Lattice Structure: The most basic 3D printed lattice structures feature repeating and uniform patterns throughout the entire part. However, more advanced methods will vary the cell and beam structure to be denser in areas that need additional strength and keep the lattice less dense in areas that experience less loading. The individual shape of the cells also has a significant effect on part performance since different structures will have different mechanical properties.
• Cell Orientation: The orientation of individual cells in a 3D printed lattice structure can affect the complexity of the print. For example, it is best practice to orient the cells in such a way that they can support themselves during the printing process itself without the need for support structures. Attempting to remove supports from hundreds of small cells is not advised.