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Elastic and Rigid Behavior in Single-Material Parts

September 9, 2019

Filed under: 3D printing,additive manufacturing,CAD/CAM/CAE — Terry Wohlers @ 14:41

Note: Ray Huff, associate engineer at Wohlers Associates, authored the following.

The elastic behavior of polymers, coupled with the design freedom of AM, allows designers to produce some very interesting products. A single-material part can have rigid and springy features, all driven by design. A good example is a small catapult on display in our office. The coil around the main shaft provides the spring force for operating the catapult, although both parts are made of PA12. The image at the left shows the catapult loaded and ready to launch. The one at the right shows the catapult after launching the ball. Notice the coil spring and locking mechanism.

Recent applications have developed with this principle in mind, many using elastomers to amplify this behavior. An example is the latticed helmet liners developed by Riddell and Carbon. Using sophisticated software, designers produce thicker lattice members and meshes where more rigid behavior is needed. Thinner lattice members alloy more flex and shock absorption in other areas. Similar functionality is being developed by HP for use with TPU on its new Jet Fusion 5200 series machines. Lattice structures and hybrid flexible/rigid components are a relatively new frontier, but we expect to see more of these types of products in the near future.