Inspire 2018 Release Focuses on the Core Additive Manufacturing Audience

This release of Inspire focuses on 3D printing, which marks a return to the simulation-driven design software's roots in topology optimization. Andrew Bartels, program manager at solidThinking Inspire, explains that much of the changes in recent releases have focused on adding traditional manufacturing shape controls and sheet metal capabilities to the software.

Considering that additive manufacturing lifted topology optimization from an obscure curiosity to a valuable toolset for the industry, I’m sure that many of Inspire’s core base will be happy to see new features, including overhang shape control, semi-lattice insertion and improved PolyNURBS, fillet and shape controls.

Topology Optimization Overhang Controls Helps Additive Manufacturers

Previous releases of Inspire have focused on topology optimization shape controls for traditional manufacturing methods. These tools have considered the manufacturing method being used when they generated the part. The software would then ensure that the part generated could still be manufactured using the constraints of that particular manufacturing method. 

One of the indications that the Inspire 2018 release is shifting back toward a focus on additive manufacturing is the introduction of a shape control that will benefit 3D printing. This new shape control focuses on any overhanging regions in a part.

“The overhang shape control allows you to input an angle control for printing,” said Bartels. “We add a line that represents a print direction, and we define a constraint based on an angle from that line, say, 45 degrees for most printers. Now, the software will not create any geometry that undercuts this angle. This is used to minimize support structure.”

The printing direction will be dependant on each part, and the overhang control angle will be dependant on the 3D printer being used by the manufacturer. To determine what the overhand angle should be for your part, Bartels suggests that you refer to any documentation on your printer or contact the supplier.

Engineers and designers who use the overhang constraint will find Inspire creating a part that is optimized by the direction of the print and this overhang angle. They should notice that their prints are better able to support themselves during the printing process. This means that users will require much less support material.

“You might still need to use a little of support structure with you optimized prints,” admitted Bartels. “But you will minimize the need to add support structure in many locations.”

It should be noted that engineers using this new shape control will need to pay close attention to the print direction of their parts. Bartels demonstrated that by changing the shape direction, the resulting topology optimization can change considerably. This means that you might be working with dramatically different shapes in your CAE verification and CAD shaping stages. 

Transforming PolyNURBS into Semi-Lattice Structures with Inspire

“The first version of our lattice optimization tool was really a precursor to a version that the masses can now really utilize in terms of running lattice fills and lattice optimizations,” said Bartels.

In previous releases, the visualization of the lattice was provided using 1D beams. Now, engineers can see full 3D representations of their lattice structures. Additionally, these models can now also be saved as STL files. This means that you will be able to transfer these models into other software or 3D printers much more easily than before. 

The beams of the lattice are also fully connected, making the optimization a complete structure. The connections between the lattice beams can also be smoothed from their initial sharp edges. However, smoothing these joints will increase the size of the STL file considerably.

Bartels notes that in the future, more file formats will be supported.

Bartels suggests running the lattice optimization on a PolyNURBS model that has already been topology optimized based on its loads and constraints. The lattice function will then fill that PolyNURBS with lattice structures to maximize the stiffness or minimize the mass.

“Traditionally, we can use a couple of different objectives,” explained Bartels. “These are maximizing stiffness or minimizing mass. What we are doing with lattice is starting a final concept design. We kind of know where we want to add our lattice.”

One of the most interesting lattice updates in Inspire is the ability to tell the software how much of a model you want to fill with lattice. This creates a semi-lattice, semi-solid structure. To be frank, the result is a part that looks to be part skin and part bone, a bit like a Schwarzenegger Halloween costume.

The semi-lattice optimization of this part works as a multi-part optimization. This function determines where the lattice will start and where it will end.

“Based on the results of the optimization, engineers might find areas of their designs that they might prefer to be solid,” said Bartels. “So, in areas of high stress and high load, lattice isn’t the preferred way to fill material into that region. So, you will really want solid material in high stress areas. We have this capability within Inspire to fill in a part with partial or 100 percent lattice.”

So, why would someone want to make a semi-lattice structure? Well, the answer is to have greater control on the deflection, strength and weight of a part. Typically, the more lattice that you have, the lighter the part will be. However, the more lattice you have, the more deflection there will be in that part when it’s under stress. If you need more strength in a part, then it is beneficial to make a region that is solid.

The ends of the beams are also optimized based on a user-specified diameter input and the optimization algorithm. This means that the lattice might have varying thicknesses throughout the part.

“Engineers get a few extra options for lattice, like a target length of your lattice beams, diameters, and the percentage of the model to be filled with lattice,” added Bartels. “We will also suggest starting values for these inputs.”

Create Full CAD/CAE-Ready Geometry with Inspire 2018

The next big improvements to Inspire 2018 deal with the software’s popular PolyNURBS technology.

“PolyNURBS work very well when making organic shapes, so you can make very organic results,” said Bartels.

Before the use of PolyNURBS, translating those results into geometry was a challenge. Bartels notes that the PolyNURBS wrapping tool in Inspire has made this challenge easier, but that sometimes this method didn’t always get as close to the topology optimization results as a user might have wanted. At least, not without taking a lot of care with the wrapping tool.

In Inspire 2018, however, there is a new automatic operation that fits a PolyNURBS to a topology optimization using cage points.

“You will notice that the PolyNURBS fits to the underlying optimization result automatically,” said Bartels. He added that, if the cage points are not getting your geometry to where you want it to, you can add splits that will cut a thin member section into the results. He notes that this will often make for a tighter fit to these results.

Bartels also noted that “each time you hit fit, it gets to a little more and a little more accurate. You don’t have to fiddle with anything, you just click the button. From this point, you can make Boolean operations, and then move forward with it.”

Engineers might also be interested in Inspire 2018’s new sharpen tool. This tool selects all the exterior edges and lets you pull the geometry tighter to the outside cage. The tool has multiple settings for low, medium or high sharpening of your geometry. Using this sharpening tool, engineers will be able to fit their PolyNURBS to exactly match their cage.

From there, Bartels notes that engineers can transfer the design to a CAD system for further development, or they can keep the geometry in Inspire, where they can use the software’s new fillet tool.

In other words, Bartels explains that the designer can create near-complete geometry within Inspire. Engineers will be able to send this geometry to a CAD/CAE/3D printer system, where designers and engineers can hit the ground running using measurements, simulations and drawing tools directly on top of the Inspire model.

“You now have exact control of the PolyNURBS and exact control of the fillets on your model,” said Bartels. “This is a good starting point to make lattice or to send this to a traditional printing process. These new tools really add to the PolyNURBS capabilities, which we find a lot of additive users really like as they are easy to use and create organic shapes, so they can rerun them in Inspire, or send them to print.”

solidThinking has sponsored this post. They have no editorial input to this post. Unless otherwise stated, all opinions are mine. —Shawn Wasserman