Lattices are repeating open structures that replace solid material with an internal network of struts or cells, a bit like the inside of a bone. They let you dramatically cut the weight of a part while keeping a large proportion of its strength and stiffness, and SLS is one of the very few processes that can print them easily, reliably and at scale. Where a solid block wastes material in the middle where stress is low, a lattice puts material only where the load actually flows.
Because SLS needs no internal supports whatsoever, even the most intricate internal lattice prints cleanly, with the surrounding powder doing all the supporting work. That makes it a firm favourite for lightweight engineering projects that come through our MJF & SLS printing service, from aerospace inspired brackets to padded protective gear.
Why SLS suits lattices
A lattice is, by its very nature, full of overhangs and internal voids that would be effectively impossible to support and then clean in most other processes. In SLS, the surrounding powder cradles every individual strut as it forms, so the structure prints without any compromise, and the loose powder caught inside the lattice is simply flushed out afterwards through escape openings.
This means you are free to design a lattice purely for mechanical performance, choosing the cell shape and density that gives the behaviour you want, rather than being forced to simplify it just so the printer can physically build it.
Where lattices pay off
Lightweighting matters most in applications where every gram of mass costs money, fuel or performance, such as drones, robotics, motorsport components and wearable gear that someone has to carry all day. Lattices also happen to absorb impact energy very well, which makes them excellent for padding, bumpers, helmet liners and other protective components that have to spread a sudden load.
They can even be tuned to be stiff in one direction while remaining compliant in another, giving designers a level of control over how a part behaves under load that simply is not possible with a block of solid material. Designers often pair a dense lattice in high stress zones with a sparse one elsewhere to shed as much mass as possible while keeping the part safe.
Types of lattice cell
There is no single best lattice, and the right one depends on the job. Strut based cells such as cubic or octet patterns are simple, predictable and easy to analyse, which makes them a safe default for structural lightweighting. Surface based cells, often called gyroids, flow smoothly in every direction, drain powder well and tend to suit energy absorption and airflow applications where a tangle of sharp struts would be a nuisance. Wall thickness around the lattice also matters, since a thin solid skin over an open core gives a clean outer surface while the lattice carries the load underneath.
Whichever family you pick, the cell size is a balance, since smaller cells give a finer, stronger looking result but make powder removal harder, while larger cells clear easily but can feel coarse. We help you settle on a cell that prints cleanly and performs the way your part needs.
Designing a good lattice
The key design choices are the cell type, the strut thickness and the overall density, and crucially these can be graded across a single part so that material sits only where it is genuinely needed for strength. Powder escape is essential, so the design must include openings that let the unfused powder clear out of the internal structure.
- Grade density so material concentrates only where load is highest.
- Choose strut based cells for predictable structural lightweighting.
- Choose gyroid cells for impact absorption and easier powder drainage.
- Add escape openings so trapped powder can be flushed out.
- Balance cell size between strength and ease of cleaning.