In 3D printing, a material’s flexibility refers to how much it will bend when load or force is applied – as well as its ability to return to its original shape after bending. Flexibility is often defined as the flexural modulus (MPa). The higher the MPa, the less likely a material is to bend under force. Nylon, for example has a flexural modulus of 500MPa. TPU, on the other hand, is about 75 MPa, with PP being 300 MPa.
Flexibility is important because it enables parts or tools to give way, when force is applied, or when something bumps into them. This enables these parts or tools to perform tasks that require a gentle touch.
The following applications are commonly 3D printed using flexible materials:
Created with flexible materials, “bumpers” can push glass or other breakable materials to the side without breaking them. Heineken uses flexible materials for this purpose in its bottling plant in Seville, Spain.
With the ability to deform to the right geometry and allow for a tight fit, sealing joints created with flexible materials can be used in all industries that use or process liquids or oils in their factories.
Using flexible materials, some companies create grippers than allow gentle handling of products. Gerhard Schubert GmbH, does just that for its top-loading packaging machines.
"The ability to print flexible materials is extremely important for many of our customers. Ultimaker printers print these flexible materials exceptionally well,” Bart van As, Product Manager Mateirals at Ultimaker, said. “Additionally, our partners in the Ultimaker Material Alliance have recognized this exceptional capability, which is underlined by the data: over 15 different flexible filaments with a wide range of properties are available through the Ultimaker Marketplace.”
The following are some of Ultimaker’s material partners that offer flexible materials. You can find more on the Ultimaker Marketplace.
"3DXFlex TPE provides excellent energy return for flexible parts,” Steve Serpe, Market Manager at Arkema, said. "Pebax® elastomers are world renowned in industries like running shoes and skiing for this energy return, light weight, and consistent properties across a wide temperature range leading to excellent performance in some of the most demanding applications."
“At DSM, we have done extensive research on 3D printing with flexible materials,” Daniëlle Glasbergen-Benning, Application Development Specialist Additive Manufacturing at DSM, said. “The main challenge frequently seen with flexible materials is the filament getting stuck in the printer, therefore interrupting the printing process. A common culprit is the buckling of the filament and grinding at the transport wheel. Arnitel® filaments have a surface that is lubricated in order to reduce surface friction and interruptions during the printing process, while keeping interlayer adhesion in the printed part intact.”
"Lubrizol’s ESTANE® 3D TPU F series range from Shore A 70D down to Shore A 94 with different, greater levels of flexibility (compared to other rigid engineering polymers) as we lower in absolute value the hardness of the TPU,” David Pascual, Global 3DP Marketing Manager at Lubrizol, said. “TPU inherent structures enable printed parts to be flexible, based on a property called Shore hardness, which determines the flexibility or hardness of a material."
Interested in learning more about Ultimaker’s flexible material partners? Visit the flexible materials page on the Ultimaker Marketplace.