If you do a google image search on metal Additive Manufacturing you will see a lot of images with lattice structures. Why would this be so?
First of all, no other process can do it. These intricate structures, especially with small feature sizes, can’t be manufactured any other way. If you need that lattice structure for some functional reason, 3D printing is the way to go. There are a lot of advantages of implementing lattice structures into a design. For the medical industry, tissue integration is important. For that and other applications, stiffness control and tunability is possible with them. For aerospace, you can’t beat the strength-to-weight ratio that can be achieved with a lattice structure– especially if it is coupled with skins. Those skins can even vary over space to be thick where needed and thin elsewhere to keep the weight down.
Second, Selective Laser Melting likes lattice structures. They has a number of benefits that make printing easier and gives better results when you use them. Because they remove material in the middle, there is less print time and the parts will come out cheaper– so you get better performance for lower cost.
You will also see less geometric distortion when you use lattice structures. The internal stresses in the part are lower with these during build so you are less likely to have parts lift and fail during build. This is especially important Powder Bed Fusion in metals (a.k.a. DMLS or LaserCUSING). The final geometry will hold its intended shape better when you use them.
It also serves as a sort of built-in support structure if you want to house a complex geometry. The example below, for example, had a complex tube network on the inside. The outside geometry is defined by its need to interface with a robot and suction cups. Those intricate internal parts would need an elaborate support structure if not embedded in a solid material. A lattice built of sufficiently small cells will enable beautiful printing and support automatically.
One trick we’ve found is that we get better results if we randomize the lattice pattern slightly. The figure below shows how a consistent lattice can result in line patterns in the skin as they attach in a regular pattern. Notice the subtle horizontal lines at the same spacing as the grid.