Bionic designs elevate 3D structures

Festo, a supplier of automation technology based in Esslingen, Germany, has long looked to nature to find superior solutions for the design of complex structures. As founder of the Bionic Learning Network, the company cooperates with universities, research institutes and private inventors to create new methods to transform manufacturing processes. One focus is the production of structures that are lightweight, yet strong and durable. Recently, Festo analyzed how spiders and butterfly caterpillars create intricate shapes for webs and cocoons. The company then used these processes as 3D printing models for a noteworthy innovation: The 3D Cocooner.

Festo was especially interested in three-dimensional lattice structures certain spiders and caterpillars produce. Lattice structures offer a whole range of benefits, including reduced material cost, lighter weight, faster production time, and increased flexibility, to a number of industries, including the aerospace and automobile industry.

While most 3D printed structures are built up layer by layer on a platform, Festo takes a radically different approach. For its 3D Cocooner, it set up a specialized tripod and a robotic nozzle, also known as a spinneret, that can be precisely maneuvered. The tripod receives the necessary positional data directly from an animation software program used for virtual 3D models, computer graphics and simulations.

The spinneret extrudes a soft threat cured with resin. This resembles the process with which spiders and caterpillars construct their webs and cocoons: They produce a fluid that polymerizes into a solid thread outside the body.

As soon as Festo’s resin-soaked fiber, the 2400-tex glass-fibre roving, comes out of the spinneret, it is hardened by exactly pointed and regulated UV light. The resin can also be kept liquid for a while by reducing the amount of UV light so that it will serve as glue for new parts. The fiber is then cut off with a small cutting disk so that the spinneret can start over in a different place. This way, the 3D Cocooner can produce complex, free-standing, lattice-like 3D structures rapidly and precisely.

Not only the object but the entire handling system is stored in the software. The actual production process can be started directly from the software without any further steps. “This direct path from the design to the production tool is very unusual in the current production environment,” says Festo in a statement. “It is, however, an important prerequisite for customized manufacturing processes in the future.” This method allows small production runs and ultimately the production of individual, customized products at reasonable costs.

The technology opens up new opportunities in many areas, including the packaging and medical technology industries. By creating and direct path from the designing to the production tool and by integrating the spinneret into the tripod, the developers are also testing how existing standard components can be enhanced for digital fabrication.