A Quick Introduction to Lattice Structures in Creo

Additive manufacturing (sometimes called 3D printing) opens up new worlds for product designers. That’s because you’re no longer constrained by the familiar limits of traditional manufacturing.

For example, if you expect to mill a part, you might have to make sure the holes in your 3D model match drill bit sizes available to the manufacturer. Or for injection molding, you’ll need to use adequate draft angles so the part can be ejected from the physical mold.

Additive manufacturing does away with those and many other limits, offering more flexibility to design intricate shapes. Among your powerful new options? Lattices.

In a recent presentation, “Additive MFG Lattice Structures,” PTC University and Creo Curriculum Manager, Matt Huybrecht, defined lattices, explained the types available, and more.

Here are the five key takeaways from his talk:

1. What’s a lattice and why would you use one?

By definition, a lattice structure is a space-filling unit cell that can be tessellated along any axis with no gaps between cells. Lattice structures are comprised of three parts: nodes, beams, and cells. They are an emerging solution to weight, energy, and advanced manufacturing time reduction. 

Another benefit is that they have a good strength-to-weight ratio. In addition, they have a high surface area, which works well for heat dissipation. This could prove helpful as you work with computer heat sinks, for example.

2. How can Creo help you design lattices?

Additive manufacturing features have been given an upgrade in Creo and we’re excited to show you. Now, there are new formula-driven lattice types available, along with a new stochastic beam lattice. You can now create your own custom lattice cells and learn how to use the build direction analysis to optimize your model for 3D printing. Read on to find out more!

3. The four types of lattice structures

Creo supports four types of lattice structures: beam-based, 2.5D, formula-driven, and custom. Let’s discuss the functionality of each below:

• Beam-based – Adds 3D cells in a pattern of your selection. You can select the cell shape and control its structure by defining the number of beams of the cell. You can control the width and shape of the beam, and also choose whether to add balls on the beam intersections. You can control how the lattice cells are propagated in the internal volume.
• 2.5D – Extrudes a prismatic, planar shape perpendicular to the plane to form the lattice cells. You can select which cell shape to use, and control how the lattice cells are propagated in the internal volume. Slot-shaped drain openings can also be added to the structure.
• Formula-driven – Uses a formula to define the lattice cell shape.
• Custom – Uses a part that you create in Creo Parametric and imports it into the lattice.

4. Stochastic cell lattices

A stochastic cell lattice by its definition is random. That is, the system creates a randomly shaped lattice using beams and nodes. There are two very good use cases for a stochastic lattice:

• Create conformal lattices – These are lattices created on the part bounding surfaces, so they conform to the part perimeter.
• Create foam-type interconnected beam lattices – This is common in the medical industry where you create a porous stochastic lattice similar to that of closed cell foam in that you can use them to fill the gaps in sandwich-type structures.

Stochastic lattices provide an alternative to uniformly distributed lattices.

 

5. Optimizing your build direction

The build direction is one of the first decisions to be made when designing for additive manufacturing. You can run a build direction analysis to help determine the best orientation of the part on the build tray to yield fewer support structures, less material, shorter print time, and less post-processing which involves removing supports. The Build Analysis option is in the Analysis tab in the Creo ribbon. After selecting the build tray datum plane, you can view the critical angles in red, the sub-critical angles in yellow, and the minimal area size. At this point you can run one of three different optimization analyses:

• Downskin area – Computes the optimal orientation to minimize the quantity of support structures.
• Shadow area – Computes the optimal orientation to reduce the shadow area of the printed part on the tray. Reducing the shadow area means that you can print more parts at once on the printer tray.
• Height – Computes the optimal orientation to minimize the height of the printed part on the tray. This usually results in a faster printing.

For more tips and tricks, check out the new LEARN classes now available online.

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