Topology Optimization is key if you are looking for a better way to design a model that meets all goals efficiently, looks aesthetically pleasing and comes in under budget. This blog article covers modeling tools and is the third and final entry in a series of blog articles covering a practical workflow and best practices for using the Topology Optimization module within SOLIDWORKS Simulation.
In case you missed the first two:
>> Part 1: Topology Optimization: Introduction to Part Creation
>> Part 2: Topology Optimization: Simulation
Exporting the Results
Once you find a form that works for your application and manufacturing constraints and reviewed the material mass plot to determine an appropriate amount of material to remove, the user can create a preview of what a completed part could potentially look like.
This is referred to as "smoothed mesh". It reflects the results from the material mass plot but removes the external jagged edges that are a relic of the way the study meshed during the original simulation. It translates the study mesh into an STL mesh.
The user can then export this result as a mesh body that can be directly printed using a 3D printer. The options for export are Graphics, Solid, or Surface mesh body.
Mesh bodies are defined entirely by their facets but without reference to equations. For example, what appears to be a circle in a graphics body is actually a large number of triangles. The edges approximate the circumference of a circle. These mesh edges do not actually form a mathematical curve.
- Solid: The part will be 3D printed, or exported as an STL, for digital fabrication. Solid is for when simple additions or subtractions need to be made to the body such as hole cleanup/addition, logos/labels, etc
- Surface: When the part will be used to generate reference material for parametric design. When an undesirable mesh geometry needs to be cleaned up.
- Graphics: For large parts when facet count exceeds 500,000 faces. When speed/ file size is a concern. When topology study only serves as a general reference to determine the shape of a part that will be designed. Graphics bodies are more of a reference body that does not have independently selectable faces but rather serves as a reference to assist in building in-context parts.
The resulting mesh shape can be uploaded to an entirely new file, a new configuration in the existing part file, or the current configuration. At this point, the optimized part can be printed for immediate evaluation or even fit testing.
Parametric Modeling Intro
In order to truly realize the results of a topology study, the part must be rebuilt using parametric SOLIDWORKS features. This will not only allow the designer to implement their design intent, but it will make the model more robust and resilient to change. While the results of a topology study may be ready for additive manufacturing, there is still much work to be done to elevate the results to the same level of quality we expect from SOLIDWORKS parts. Think about how much time you might put into creating a simple component. Well, that same level of care will need to go into this part, and since it is more complex, it will require more features.
Since the output of a topology study is in mesh format, there are specific tools we must use to parameterize the model. Here are a few workflows you can employ to achieve these results:
- Simple: Use the mesh output to develop simple 2D cross-sections which can be extruded and cut away to create a parametric shape.
- Advanced: Develop reference geometry such as planes and axes to rebuild the topology output using advanced SOLIDWORKS features. This tactic will be the most involved, but it will also be the most consistent with analysis results.
- Mesh Modeling: SOLIDWORKS includes mesh modeling tools that allow you to create traditional features and convert them into mesh bodies that can be directly added or removed from the topology study output.
The fastest way to generate parametric models of topology optimized parts is to recreate the profile of the optimized shape using 2D sketches which can drive parametric features. This will give you the fastest result based on your analysis results. This approach is also the most conservative since the least amount of material will be removed from the base part.
When critical structures are found and need to be parameterized, the designer should define a plane that runs through the critical regions. The designer can then simply sketch a 2D cross-section of these features.
Another option would be to use the Slicing tool to capture all intersections of the optimized mesh model which pass through that plane.
To truly capture all of the complex geometry shown in our analysis results, more complex and detailed features will be needed. This more involved approach requires the deliberate and careful referencing of the topology results. The designer must also consider the following:
- Which critical surfaces, basic geometry, and features must be present in order to retain full functionality?
- What regions and dimensions would you like to be able to edit rapidly, and how can they be built so they are resilient to change?
- What region would be the most important as a foundational feature upon which other features can be built?
One way to break down the analysis result is to think of the resulting geometry as a series of cylindrical members. Each of these members can be rebuilt using lofts, sweeps, and even boundary features. The first step in all of these cases is to first define a cross-sectional reference plane. Sketch profiles and central paths can then be built using this reference. Items such as flat surfaces, threaded holes, and mating surfaces must be re-inserted to preserve the design intent of the base part.
This approach is nearly identical to general best practices for any SOLIDWORKS part. The primary difference is that instead of a drawing or a sketch to use as a reference, a mesh model will be used. In many ways, this is easier since the 3D shape can be referenced.
Mesh Modeling Tools
SOLIDWORKS offers a robust set of tools specifically built to manage mesh models. These tools are another efficient way to convert your analysis results into a usable, parameterized model. Since the output of the topology optimization study is already a mesh body, these tools can be used to simply alter this body without having to re-create any geometry at all!
These tools are purpose-built for reverse engineering and can be used to incorporate any mesh body into your SOLIDWORKS designs. Here are some of the primary techniques that designers can use to manage mesh models:
- As we discussed earlier, the Slicing tool can be used on mesh bodies to generate sketch profiles as references or seed sketches for 3D features.
- Surface from Mesh is a tool that allows users to copy or offset surfaces of mesh bodies to act as boundaries or end conditions for 3D features. The resulting surfaces are SOLIDWORKS BREP surfaces and can be manipulated using traditional surfacing tools.
- Segment Mesh Body can help users isolate and extract planar, cylindrical, and conical geometry to generate reference geometry. This will allow for the discreet selection of faces, edges, and vertices of the initial mesh body.
SOLIDWORKS offers incredible tools that allow for shape development and part optimization backed by FEA insights.
As we discussed, one major factor in the adoption of this technology is the scalability of production. Many people assume that this technology can only be realized using additive manufacturing. But with using the intuitive tools available in SOLIDWORKS, you can design these components with manufacturability in mind right from the start; regardless of what industry you are in.
Read our in-depth white paper on using these dynamic tools available in SOLIDWORKS so that you can use topology optimization to design components with manufacturability in mind right from the start, regardless of industry!