Topology Optimization for 3D Printing

The traditional design cycle creates product geometry before validating and optimizing a 3D CAD model against any requirements. After a meticulous process of sketch, analysis and prototype generation, the design may still be far from optimal due to constraints or market demands to reduce product development time. The current trend for high-quality, lightweight products with improved performance and user experience requires an optimized concept design at the very beginning of the product development cycle.

A generative design approach, instead of the traditional design process, can meet the needs of the demanding product development cycle. This approach allows for creation (or redesign) of a product based on a given set of requirements while allowing the design to be optimized within the predefined constraints. Therefore, the initial concept design generated is a validated one, although further optimization iterations can be continued as needed to meet the design goals.

Generative Design Approach

As stated by one of the pioneers of generative design approach, Professor Celestino Soddu, “Generative design approach works in imitation of Nature, performing ideas as codes, able to generate endless variations.”¹ This approach doesn’t result in multiple random design configurations but creates one design that is already optimized for its operating environment. With advances in 3D printing technologies, the rise in computing power combined with data analysis and machine learning algorithms, generative design is becoming a crucial step in the product development cycle. Topology optimization is one of the tools or subsets of generative design.  

Traditional process:

Upcoming process: 

Topology Optimization

Topology optimization has been available since the late 1980s, however, technology limitations prevented its widespread adoption. As the manufacturing process is being revolutionized with the advent of additive manufacturing, topology optimization is set to be a critical step in designing for additive manufacturing or 3D printing. It’s a subtractive technology where we start out with a volume of material defining the design space. The topology optimization algorithm iterates to remove material from the design space, based on predefined design goals, design requirements and real-world operating conditions such as loads and fixtures.

SOLIDWORKS and Topology

SOLIDWORKS users can leverage generative design using the topology study option available in SOLIDWORKS Simulation 2018 and higher versions. Using the topology study, users can define their design goal to either minimize mass, maximum displacement or achieve best stiffness to weight ratio. Design constraints can be of type Displacement, Mass, Stress, Factor of Safety or Frequency constraint.  

The solution of a topology study results in a design that has optimal material distribution based on the pre-defined criteria. Shown in the image below is an optimal design for minimum weight and maximum stiffness goal.

Mesh Facets

The optimized shape shown in Material Mass plot (with smoothed mesh) can be exported to a mesh boundary representation (BREP) body. This mesh created is independent of the mesh representing the finite element model of the geometry in Simulation. The export mesh option allows it to be saved to a solid or surface body, which is made up of mesh facets (triangles) forming a watertight volume. Using the option “Group facets into faces” will collect the mesh facets into selectable faces.  

Exporting Files

Optimized shape generated from the topology study can be directly exported for 3D printing purposes. Available file formats for exporting the model are *STL, 3D manufacturing format (*.3mf) or Additive manufacturing file format (*.amf).

Using the File > Print3D option, users can go straight from the optimized model to 3D printed output. Depending on the type of 3D printer available on the user’s network, the appropriate 3D printing property manager will be displayed to allow for customized settings.

Manufacturing & 3D Printing

Per Deloitte’s market research on trends in additive manufacturing, by the year 2020, 75% of manufacturing will rely on 3D printing tools. With SOLIDWORKS’ ability to directly export the mesh of optimized design to CAD geometry and SOLIDWORKS 3D print feature, users can swiftly print the prototypes or even the final product design.

This seamless connection between geometry creation, simulation and 3D printing in SOLIDWORKS topology study allows users to efficiently create optimal designs that were previously impractical to manufacture and still reduce the overall product development cycle time. 

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References:
¹3D Printing Generative Design Tool From Desktop Metal Makes Waves at SOLIDWORKS World

²SOLIDWORKS 2019 Digital Launch presentation