One of the most impressive features of 3D printing is the ability to fabricate parts with complex internal lattice structures, which is not possible with traditional manufacturing techniques. Designing a part around a lattice reduces its overall mass without significantly affecting its overall strength. This article will discuss how 3D printing can take advantage of mesh structures to take product design to new levels in terms of mechanical strength and cost reduction.
What is a 3D printed lattice structure?
Simply put, a 3D printed lattice structure is a repeating or non-repeating 3-dimensional collection of connected nodes. In its simplest form, multiple lattice nodes are connected to each other by beams. In the case of repeating 3D structures, the collection of beams and nodes takes on regular and repeating 3D shapes such as cubes or tetrahedra. These shapes are often called cells. The shape and density of these elements will determine how the part behaves when a load is applied.
3D printing lattice structures allows optimal use of the unique capabilities of materials and printers by placing mass only where it is structurally needed. Therefore, the overall project is much lighter than a completely solid project. This is one of the reasons why lattice structures are so common in nature. For many years, this principle could only be implemented on large buildings such as steel buildings. However, with the advent and growing popularity of 3D printing technology, it has become possible to create smaller, more mundane parts and products with internal lattice structures. It can be used for both mechanical strength and aesthetics. This method greatly reduces the quality of the part.
Generate lattice structure
Due to the complexity of the lattice structure, it is impractical to model it into the part using typical CAD tools. In most cases, parts are drawn in CAD as if they were solids. Then, after the part design is complete (considering DFAM principles), the model is imported into another software package to generate the lattice structure. The more common programs in this regard are Netfabb or nTopology.
Another way to generate 3D printed lattice structures is through generative design. In this case, the connection points, mass limits, and expected loads for the part are defined. An algorithm then generates hundreds of solutions that satisfy the requirements. From this, the optimal lattice cell structure and cell density can be selected from the solution or generated by further iterations. When creating lattice structures, it is important to understand what factors affect the overall functionality of the final part. These factors are as follows:
1.Lattice Material: When 3D printing in metal, the lattice is usually the same material as the entire part. However, if a flexible lattice is required, then multi-material parts can be considered. Some products use a soft, flexible material for the lattice and a more elastic material for the shell to protect the lattice. A common example is running soles.
2.Lattice structure: The most basic 3D printing lattice structure has a repeating and uniform pattern throughout the part. More advanced methods, however, will alter the element and beam structure to be denser in areas where additional strength is needed, and keep the lattice density lower in areas subject to less loading. Since different structures will have different mechanical properties, the individual shape of the cell also has a significant impact on part performance.
3.Cell orientation: The orientation of individual cells in a 3D printed lattice structure affects the complexity of the print. For example, best practice is to position cells in such a way that they can support themselves during printing without the need for a support structure. Trying to remove hundreds of small cells in removing supports is not recommended.
The benefits of lattice structures
Lattice structures for 3D printing offer a wide range of benefits. Some of the most important questions are listed below.
1.Reduce part cost: Depending on the material, 3D printing can be an expensive process. This is especially true of titanium or Inconel materials commonly found in the aerospace industry. The introduction of the lattice structure means that less material will be used, making the part cheaper overall without sacrificing structural integrity.
2.Improved strength-to-weight ratio: Parts with lattice structures can have unmatched strength-to-weight ratios if designed according to the accepted principles of DFAM (Design for Additive Manufacturing). This makes it ideal forautomotive and aerospace applications(among others) where mass minimization is critical.
3.Shock absorption: The lattice structure is very effective in dissipating shock and shock loads, as the cell structure contributes to bending and energy distribution throughout the structure.
4.Increased surface area: Some applications focus on maximizing surface area rather than mechanical strength. For example, heat transfer or chemical reactions may be the primary target. Lattice structures are useful here because they give the part more surfaces without increasing its overall footprint.
5.Osseointegration: This refers to the method of creating lattice structures in medical implants to promote bone growth. The resulting implant forms a stronger bond with the patient’s own bone structure。
Generally speaking, 3D printed lattice structures allow engineers to push the limits of materials science while reducing overall part quality. Lattice structures have only recently begun to move from advanced aerospace applications to more common consumer goods, due to the increasing popularity of 3D printers and the reduction in material costs. This design style holds up only because the lattice is so efficient.
It’s wise to learn how to incorporate them into your designs to take full advantage of them. To learn more about how parts can benefit from lattice structure, contact us today.