3D printed lattice structures are one of the biggest selling points of additive manufacturing. They are easy to fabricate using the unique process of 3D printing, and there are many practical benefits to using them.
Lattice structures are essentially infill patterns — ways of structuring the internal geometry of a 3D printed part. Instead of 3D printing a solid block of plastic or metal, engineers can use overlapping, interlocking patterns that are partially hollow. When these lattices are designed properly, they can greatly improve the mechanical properties of a part, making it lighter and stronger.
Importantly, lattice structures can be fabricated on any professional-grade 3D printer. And more importantly still, these structures cannot be adequately produced using any other manufacturing technology. Subtractive technologies cannot cut the inside of a part without cutting through the outside, while molds simply get “filled up” with liquid material — you can’t pick and choose how that liquid material falls into place like you can with a 3D printer.
This article looks at how 3D printed lattice structures are made, and why they’re becoming so useful in places like the aerospace industry.
How do you make a 3D printed lattice?
Lattice structures can be seen everywhere in places like bridges and timber houses. The Eiffel Tower is perhaps the world’s most famous example of a lattice or truss structure, with its overlapping beams forming a stable but largely hollow structure.
It is possible to replicate such a structure in a 3D printed part. And it is generally not necessary to design the lattice framework manually: several lattice generation tools exist which automatically generate lattice patterns based on parameters chosen by the user. Commercially available tools include topology, Autodesk Within, and Meshify.
But not all lattices are the same. In fact, lattice structures vary in many ways, with the key variations described below.
Cells are the individual units that make up a lattice structure. These are usually recognizable as geometric shapes such as cubes, stars, hexagons, octagons, etc., although multiple shapes can be combined for specific mechanical uses. Sometimes the cells are entirely non-uniform, with no discernible pattern.
Ultimately, the cell structure — both its shape and size — affects how a part will behave in terms of strength, weight, elasticity and other factors.
Deciding on the structure and size of the cell is only half the story. The shapes within a lattice can be oriented in different ways, which also affects the ultimate performance of the part. Orientation should also be determined by printing constraints: certain orientations will require more support structures, for example.
Not all materials are capable of printing all lattice structures. Soft and elastic materials should generally not be printed with large cell structures, since the large porous sections may make the part sag. In most cases, the lattice material will be the same as the shell or external material, but multi-extruder printers offer some flexibility in this regard.
What are the benefits of a 3D printed lattice?
By incorporating lattice structures into 3D printed parts, engineers can reap benefits such as weight reduction, improved part strength and shock absorption.
Weight reduction is perhaps the most important of those benefits and the main reason why engineers are so keen to optimize their printed structures with patterned internal geometries. A key feature of lattice structures is their partial hollowness: cells contain empty space, so apart with an internal lattice pattern features less overall material than an equivalent part with solid infill.
Less overall material means less mass, which is a huge advantage for AM users in industries like automotive and aerospace, where shaving off just a few grams can make a huge difference to part performance. In fact, some of the most exciting lattice research is taking place in aerospace, where companies like Boeing have developed super-lightweight advanced lattice materials.
Less material also means less expenditure. By creating parts with lattice structures, engineers can create superior parts that actually cost less than inferior ones.
But the whole point of lattice structures is to reduce mass without compromising the integrity of the part. While poking arbitrary holes in a part could make it more brittle and more likely to break, 3D printed lattice structures are designed to use the material in the most structurally effective way possible, ensuring the hollow sections are not vulnerabilities, but strengths in themselves.
Partially hollow parts with lattice structures can actually be stronger than their solid equivalents, because the empty spaces in a lattice serve to improve shock absorption and reduce impact stress. Parts with large-cell lattice structures can be highly flexible and elastic, reducing brittleness and possibility of breakage.
Less important but still notable are the aesthetics of lattices. These complex patterns are some of the most impressive forms that engineers can make with a 3D printer, so parts with printed lattices are often as visually arresting as they are practical.
Benefits of 3D printed lattices summary:
- Less material usage
Can CNC machines make lattice structures?
In short, no. CNC machines and other subtractive manufacturing technologies cannot make 3D lattice structures because they use cutting tools to remove material from a solid block. A CNC machine could cut away the hollow sections of the first row of lattice cells, but the cutting tool would then hit a dead end. It cannot cut the next row of hollow sections because the solid sections are in the way.
A 3D printer does not encounter this problem because it fabricates parts in slices or cross-sections, building them up from nothing rather than cutting them down from a solid block. Additive manufacturing is therefore far and away from the best manufacturing technology for creating lattice structures.
Note, however, that CNC machines can effectively create 2D lattice structures such as grilles, and these specific CNC machined lattices may, in fact, be stronger than 3D printed lattices.
What are the practical applications of 3D printed lattices?
3D printed lattice structures already have applications in many industries, since engineers and product designers across the commercial spectrum are constantly seeking ways to lightweight and strengthen parts.
Weight reduction is especially important in the aerospace and automotive industries since heavy parts generally reduce vehicle speed and lead to greater fuel usage. Lightweight parts are therefore far more desirable.
Given that truss structures have existed in architecture for hundreds of years, it’s no surprise that miniaturized versions of lattices are also becoming popular in today’s architecture landscape. And because lattice structures can be precisely engineered, researchers have even found ways to create 3D patterns that reduce noise, potentially improving insulating materials for buildings.
3D printed lattices are also found in clothing and footwear, with companies like Adidas using 3D printed elastomer lattices for sneaker midsoles. These lattices provide a lightweight cushion with a huge amount of bounce — far better and more scientifically justifiable than the ubiquitous “air bubbles” of the 1990s.
3D printed lattices with 3ERP
3ERP is an experienced provider of 3D printed parts and prototypes, and we are capable of producing high-quality lattice parts for a variety of applications.
Our additive manufacturing services include FDM, SLA, SLS and SLM, all of which can be utilized to create complex internal geometries.