Lattice structures in 3D printing are a powerful design tool. Carefully designed truss structures can make parts lighter, stronger, more effective at absorbing impacts, and better customized for end use. Understanding how to use and create these structures is an important part of product engineering and industrial design for 3D printing prototypes and production parts.
Lattice structure is actually a special application of 3D printed infill pattern, but most non-professional designers do not fully utilize its role. Today, advanced additive manufacturing design software has great advantages in automatically generating various lattice structures, which provides a good basis for the application of lattice structures in sports equipment, rocket boosters, implants medical and other fields.
In this article, Antarctic Bear introduces the basic points of using truss structures to design parts one by one, including the advantages of truss structures, different types of truss, how and when to use them, and shows how to use them around the world. How designers and engineers use lattices to create innovative, high-performance products: from Adidas running shoes and Specialized bicycle saddles to industrial heaters and orthopedic knee implants. Finally, the main software needed to apply truss structures to your designs is covered.
△Aidro 3D printed heat exchanger with internal lattice structure – Toucan Beak (Source: Aidro)
Crystal lattices have unique properties that provide great advantages when designing parts or products that are almost impossible to reproduce with traditional manufacturing methods, such as:
Using a mesh in your design can significantly reduce the amount of material used by removing most material in non-critical areas. If the target part is manufactured using a powder or resin-based 3D printing process, significant savings can be achieved.
Another benefit of reducing material usage is weight savings. In many applications, the quality of the final assembly of a part or assembly is a narrowly limited goal, generally the lighter the better. Depending on the type of mesh chosen, weight savings can be significant, providing many benefits, from reduced fuel consumption in automotive applications to faster patient recovery times in medical cases.
Lattice structures have many properties conducive to energy absorption. By varying the density or even cell type in different areas, designs can be made to effectively absorb energy coming from different directions. The complex lattice structure better redirects and distributes energy in multiple directions to absorb impact compared to standard foams used in a wide range of products, while taking advantage of the diverse properties of modern additive manufacturing resins.
△SuperTacks CCM
The surface area of a lattice is several times greater than the surface area of a solid component of the same size. This is useful for applications involving heat exchange or chemical catalysis that require high surface area for their functions.
In addition to the many technical benefits of trellises, it’s hard to ignore that they have a unique and beautiful aesthetic. More and more product designers are choosing to incorporate lattice elements into consumer product designs simply for appearance reasons.
△Carbon Design Engine lattice type used in lattice generation software (Source: Carbon)
Concerning the definition of lattice types, Anton du Plessis and others have conducted a systematic discussion on this subject. The relevant research was published in the journal “Progress in Materials Science” in an article titled “Properties and applications of additively manufactured metallic cellular materials: A.” higher opinion.
Links to related articles:
All types of truss are based on the same unit cell replicated repeatedly in multiple directions to make up the whole structure. Here are the lattice types divided by cell type:
When you use trigonometric equations to generate a unit cell, a TPMS (triple periodic minimum surface) network is created. For example, a “gyroscopic” TPMS cell consists of all points in the cell, and the following equation applies:
sin(x)cos(y) + sin(y)cos(z) + sin(z)cos(x)=0
Different but similar equations like this give different types of TPMS networks.
A pillar array (or beam array) is made up of interconnected beams connected in various patterns defined by the unit cell. Pillars can be connected by the cube’s vertices, edges, and faces, and different combinations of these connection points produce different types.
Planar networks are the simplest type of network and are created when a 2D unit cell is extruded into 3D. The most common type of planar network is the honeycomb structure.
Each of these network types can also change from periodic to random by randomly changing its parameters in different directions. This can be advantageous in some applications by giving the structure similar properties in each direction (making it isotropic).
When it comes to trellis generation software, you may encounter the following types of trellises:
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Icosahedron: Irregular network characterized by the arrangement of points in space.
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Tetrahedron: Lattice based on a tetrahedron with four triangular faces. Each vertex is connected to three adjacent vertices by edges.
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Rhomboid: The unit cells of a lattice are diamond-shaped (tetragons of equal length) and they are connected to adjacent unit cells at their vertices or edges.
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Voronoi: A network in which space is divided into cells based on proximity to a set of starting points.
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Kagome: a lattice structure composed of a repeating pattern of triangular units
Many different industries have taken advantage of the properties of lattice structures when designing new products, and recent years have seen a proliferation of new applications and ideas of which lattice structures are a key feature. Some of the most interesting and innovative products are listed below.
△Puntozero cold plate for DynamisPRC electric racing car (Source: nTop)
Italian product development agency Puntozero worked with the Formula SAE Dynamis PRC team to design this unusual cold plate (pictured above) for its high-voltage converters. Based on a modified version of a spiral unit cell, the cold plate structure is 25% lighter than previous designs and increases its surface area by 300%. Designed using nTop software.
△NanoHiveMedical orthopedic implants use a lattice structure that promotes bone growth (Source: NanoHive Medical)
NanoHive Medical is an American company specializing in the design of unique spinal implants for use in surgical procedures to treat degenerative spinal diseases. In this case, the truss design serves to reduce the stiffness of the implant, allowing more force to be transferred to the spine itself, thereby reducing bone atrophy around the titanium implant.
The lattice structure of knee and hip implants has been shown to promote the growth of bone tissue within the implant, called osseointegration. A recent study in the journal Bone & Joint Research found that “3D printed titanium mesh implants maintained the natural mechanical loading of the proximal tibia after partial or total knee replacement, unlike traditional solid implants.”
△Random lattice structures on 3D printed implants can be designed using software such as Genysis (left) and nTop (right).
The lattice-like structure of medical implants is not completely uniform but acts like a sponge. The type of block structure we typically use to create this bone structure is called a trabecular meshwork or random network. These networks are called biomimetic trabecular bone types and, at a fundamental level, are essentially random foamy cellular structures. Specialized computer-aided design (CAD) software allows implant engineers to apply this type of surface structure to metal implants.
Since the launch of the Specialized Truss Bike Saddle in 2019, the concept of 3D printed bike saddles has become popular. Some cycling equipment manufacturers have introduced their own versions of saddles that ditch the foam padding and opt for a trellis structure. This advancement creates variable supports by 3D printing different mesh shapes and sizes in different areas. Manufacturers tout the durability of these stools, while providing ventilation and ease of cleaning. The Posedia Joyseat (pictured above, right) is custom made and personalized for each rider, a specially developed block of foam that the rider sits on to create a personalized bone width and weight distribution based on from his seated position.
Helmets are another ideal application for lightweight, shock-absorbing mesh structures, often referred to as “digital foam.” They have been used in NFL football helmets, NHL hockey helmets, Olympic bobsled helmets and bicycle helmets through various methods and materials. In fact, performance test results from the 2023 NFL Helmet Lab Tests ranked and evaluated a range of helmets on the market and ranked two helmets with 3D printed truss structures in first and second place.
△The 3D printed lattice structure is an ideal substitute for foam in helmets and has excellent impact resistance (Source: Farsoon, Carbon, EOS)
Riddell’s football helmet and Hexr’s bicycle helmet are examples of two different approaches to the lattice structure of helmets. Although both are designed to absorb shock and protect the user as effectively as possible, the differences lie in the manufacturing method and type of mesh, as well as the method of movement. The Hexr helmet mainly uses a flat hexagonal lattice structure, is produced using SLS printing technology, and is made of hard nylon 6. The Carbon Riddell headset, on the other hand, uses high-damping DLP elastomers and a complex multi-zone mesh made up of more than 140,000 individual spacers. The process leverages Riddell’s Precision-Fit head scanning technology and Carbon Lattice Engine to design helmet liners that adapt to each player’s head and position.
To simplify the process of matching materials, truss shapes, and applications, particularly for helmets, the U.S. Army Development Command’s Soldier Center tasked software startup General Lattice with developing a set of predictive modeling tools to design and generate data based on real mesh materials. . Built on more than 10 million physical data points, the toolset is a searchable database that allows users to query mesh materials based on their mechanical properties. Nick Florek, co-founder of GeneralLattice, said: “Providing tools that allow users to understand the impact potential of lattice structures up front reduces the risk of misuse and builds confidence that the 3D printing can give the results announced. »
While the Army still sticks to its toolset, General Lattice offers a public version called Frontier, which provides a free, searchable database of validated mechanical properties to help users select the best combination of lattices , materials and equipment.
△GE Additive lattice-designed radiator (Source: GE Additive)
Additive manufacturing enables geometries not possible with any other type of manufacturing, making smaller, more efficient heat exchangers possible. The complex heat exchanger above, designed by GE to optimize the flow of carbon dioxide at 900°C, is an excellent example of the superior performance that can be achieved when complex lattice structures are combined with metal additive manufacturing . GE took a bionic approach in its design, mimicking the properties of human lungs to promote efficient heat exchange. Companies such as Conflux specialize in designing 3D printed heat exchangers using mesh specifically for various industries.
Adidas Athletic Footwear teamed up with Carbon 3D to release the 4DFWD shoe in 2017 – the latest in a series of sneakers made with DLP resin technology. The shoe’s midsole features a lattice structure designed to propel runners forward with its custom FWD unit.
△The AntaresVersus Evo 00 adaptive seat cushion is printed with a Carbon 3D printer and features tuned lattice structure areas to provide optimal mechanical response (Source: Carbone)
Although a powerful and underutilized feature, truss structures have some limitations that engineers and designers who are serious about using them in real products need to consider.
Although there are traditional methods of manufacturing complex non-planar lattice structures, they are generally not as efficient as additive manufacturing methods. Therefore, the economics, lead times, and material selection unique to additive manufacturing must be carefully considered when integrating mesh into the design, especially if other areas are designed with technologies such as injection molding in mind.
When large lattice structures are involved, stress simulations, especially those using finite element methods, can be computationally intensive. Most methods, including those used by several of the software packages mentioned above, involve inferring unit cell properties throughout the structure, but if unit cell types and sizes vary widely, physical testing can be an accurate assessment of unit cell performance. only way to design performance for very large and complex networks.
Likewise, when converting part designs with large mesh sections to STL (which, for better or worse, remains the most commonly used file type in additive manufacturing), larger file sizes to 500 MB, or even 1 GB, are common. This often means that further processing and slicing is a slow and difficult process for all but the most powerful computers. It is of course possible to reduce the mesh size, but this will greatly simplify the elements and if you are not careful you will end up with a few triangular elements on the part.
The unit cell type is one of the most important characteristics of a truss structure and determines most of the different properties the entire structure will have, but most engineers and designers have limited options from which to easily choose . Some software packages allow design and design. creating a new type, but even with access to these programs it is a highly specialized and technical task.
Truss generation software and the truss features of CAD software are a common way to create truss structures. Unlike the various slicing programs typically available for FDM printing, these software programs can be used to create lattices for a variety of purposes other than just filling material, and are not generally used to generate G-code directly.
There is a wide range of complexities and features in software options, so be sure to be selective. Some typical software tools are listed below:
The new terrain-driven design in △nTop allows engineers to use simulation results as design parameters to control your design. In this lattice structure heat exchanger, simulation tools show that tightening the network improves conduction, while relaxing the network structure in areas where convection is greater (Source: nTop)
nTop offers a variety of networking options and features, making it faster than many CAD programs. Because the software is based on implicit modeling, in which 3D geometry is defined as mathematical functions rather than exterior surfaces and edges, engineers can quickly generate complex structures such as lattices while providing the reliability needed for cycles. automated design.
The truss functionality included in nTop is extremely powerful, allowing almost complete control over all aspects of the truss structure, including the ability to customize the unit cell. Field-based design is a difficult concept for experienced CAD users to master, but once you overcome the learning curve, the design possibilities with this suite are endless.
nTop offers what the company calls GPU acceleration, enabling rapid, real-time visualization of network structures. The software allows users to preview design changes and reconstruct highly complex meshes in seconds. Users can also adjust the network perimeter at each point in space and save your preferences in a reusable workflow.
Last year, CAD software giant Altair acquired a small British company that developed a powerful lattice tool called Sulis. It’s now one of three Altair matrix products, but it’s the company’s best matrix tool. Sulis are used to create complex lattice structures and fluid flow channels for use in a range of industries including aerospace, automotive, medical and industrial machinery. It is a 3D printing design software tool with an implicit modeling core specifically designed for lattice formation and one-click lattice creation capabilities that allows users to add lightweight structures to the models and refine their properties.
“Because Sulis is a CAD tool created specifically for additive manufacturing, engineers can design parts that truly take advantage of the freedom of additive manufacturing, unlocking the power of implicit geometry and reducing the risk of print failures expensive 3D,” Altair said.
Main features of the Sulis tool:
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Create a trellis with just one click
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Customizing Truss Structure Properties
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Range of unit cell types
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Real-time visual feedback of flow paths
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simple conformal geometry
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self-supporting fluid channel
If you are already an Autodesk user, some trellis structure options have been available in Fusion360 since January 2022, but a broader trellis generation mode is reserved for future expansion. As of September 2022, Autodesk added this trellis design feature as a “design extension” for $595 per year, more than double the price of Fusion 360’s annual subscription.
Still, the standard Fusion 360 mesh tools are very useful. The tool can incrementally change lattice cells in one direction, and unlike most programs that involve digging out a part and adding a lattice, Fusion360 allows its users to design a part individually. Users can create a network and then form a skin on it, allowing the cellular structure of the network to shrink as it approaches the skin, creating a cellular structure that effectively distributes local stresses from the surface to the skin. internal network. This is the most natural generation path, taking part of the femoral head as an example:
For Autodesk Netfabb users (Netfabb comes with your Fusion 360 subscription through two products), you may already be familiar with this powerful trellis generation feature. Like the older software mentioned here, Netfabb’s GUI is clunky, but it is still a powerful program capable of generating very complex trellis designs. It also has a very convenient drilling function that allows you to drill holes in the part, making it easier to dispose of unused powder or resin. To get a more advanced Netfabb network, you need to subscribe to Fusion 360 with Netfabb Premium (includes digging and trellising) or Fusion 360 with Netfabb Ultimate (includes more advanced network optimization tools).
△3D printed lattice structure image: Carbon Design Engine
Most of the images in this article are real Carbon 3D truss products. The hardware, materials, and software company saw such demand for mesh that it began making its mesh design program open source so you can use it with almost any printer.
This cloud-based network design software creates robust compliant networks in a range of cell types, but the kinds of truly useful design features are only available in the more expensive “Pro” version, which ranges between types of trellis. Transitions and gradient designs are introduced.
This design software allows precise control of performance characteristics in multiple areas of a product, enabling large-scale customization of a single material. This feature uses different array cell types, cell sizes, or pillar diameters to create different performance zones. Design Engine uses patent-pending technology to blend areas seamlessly, producing an attractive and functional mesh ready for real-world applications.
△BASF Forward AM’s new Ultrasim 3D lattice engine is designed to generate proven lattices in minutes for specific applications (Source: BASF Forward AM)
BASF Forward AM will launch Ultrasim 3D Lattice Engine powered by Hyperganic, a software solution for iterating designs with lattice patterns – a tool with many potential applications. This latest software solution is designed to extract mathematical knowledge from the network, making it easier to explore different network geometries and implement them faster into the product design cycle through a single-click approach. Powered by Munich-based algorithmic engineering software company Hyperganic, the Ultrasim 3D Lattice Engine offers users a variety of Lattice models, each tested and validated for a different set of applications.
Whether designing new footwear or protective sports equipment, there is a mesh geometry that meets the unique requirements of each application. Users have access to an extensive network library in the form of physical test pads and a digital overview of mechanical properties. By entering the desired application area, you can find validated truss designs for similar use cases. From there, the software uses implicit modeling to automatically generate truss parts tailored to the design parameters and generates a .stl or 3mf file for the truss, which can ultimately be printed and verified further.
Hyperganic construction software aims to design objects as complex, functional, elegant and durable as nature. The company said: “Our algorithms generate parts, structures and entire machines through a process of digital evolution. Our technology enables output on advanced industrial 3D printers. Since 2015, we have been working with leading companies, engineers and designers and scientists. »
In the 2022 version of NX released by Siemens, network structures in NX can be optimized using Simcenter 3D simulation to derive the optimal network structure in a single environment, eliminating multiple analysis steps. design traditionally required.
NX is a large and complex engineering software, and by purchasing it you not only benefit from the network design capabilities, but you also learn about the extensive network options that Siemens has designed for the application.
Materialize has a strong position in the market with its powerful Magics additive construction readiness package, while 3-Matic for additive design and data optimization has been around since 2004. Although it is frequently used by some large businesses and is very feature-rich, its networking functionality is difficult to use, in part because its GUI is very outdated. If generating lattice structures is the primary desired feature, there are better and cheaper options.
Although Optistruct is primarily a structural FEA solver, engineering analysis and optimization tool, it is nonetheless worth mentioning for its ability to generate a range of different truss types using its set of design optimization features. Altair’s approach to building truss structures is unique because it is intrinsically linked to the topology optimization process. The ability to accurately simulate a network after it has been designed is very useful, but it is only worth considering this toolkit if the Optistruct solver is also needed for other purposes.
Another Altair software called Inspire launched a unit cell lattice generation feature in 2020. AltairInspire generates lightweight unit cell lattice structures for 3D printing that can be easily modified to evaluate the structural performance of different design variations .
In 2022, Altair acquired a software company specializing in tools specifically for network generation and offers a solution called Sulis, described above.
△General Lattice’s Frontier software provides a searchable database of validated lattice mechanical properties (Source: General Lattice)
General Lattice’s Frontier software (currently in beta) provides a searchable database of validated mechanical properties to help users select the best combination of mesh, materials and hardware for a specific application. Users can search, analyze and order physical samples for real-world assessment, eliminating costly uncertainties and inspection workflows. Frontier said its lattice design feature is equivalent to providing a universal search key, which prevents users from looking for a needle in a haystack and significantly saves time, money and resources.
Daguang focuses on providing solutions such as precision CNC machining services (3-axis, 4-axis, 5-axis machining), CNC milling, 3D printing and rapid prototyping services.
