Composite materials allow greater flexibility. “You can design and combine multiple parts into a single build to really optimize designs for an application, as opposed to most conventional manufacturing methods, which optimize parts so that they can be manufactured,” he adds.

Most 3-D printing companies, including Stratasys, are beginning their work with composites using short fiber-reinforced materials. “You don’t have to deal with cutting fibers, and the tool paths for building a part are a little less complex,” says Schniepp. “As you move to continuous carbon fiber reinforcement for critical applications such as high-performance structures, your requirements will continue to get more stringent. The challenges are in printing the part with a continuous fiber reinforcement that results in a structure with higher quality, sufficiently low porosity and proper consolidation while meeting dimensional and other specific application requirements. Those are the things that we’re working to address.”

Stratasys plans to adapt some of its current 3-D printers to handle composites and also develop new platforms better able to take advantage of these materials.

Adding Strength

Hemant Bheda, CEO of AREVO, began exploring 3-D printing with composites when trying to make a very strong seal for a customer in the oil and gas industry. “To do that, we had to have control over the orientation of the fiber,” he says. “I asked myself, ‘Is this even possible?’ Then I came across 3-D printing technology and saw it as the answer.”

Boeing-3-d-print-tool

This 3-D-printed umbilical bracket used on the all-composite Boeing 702SP satellite establishes the electrical interface and supports the harness and connector between the satellite and launch vehicle.
Photo Credit: Boeing Research and Technology

Using additive manufacturing, Bheda can control the orientation of the composite fiber, optimizing the strength-to-weight ratios and producing higher-performance seals that have improved the speed and efficiency of the customer’s equipment and reduced maintenance and downtime.

Bheda says one problem with additive manufacturing has been that most equipment prints the part only in an XY plane, resulting in weakness in the Z plane. AREVO has addressed that by developing a printing tool with a six-axis robot (and the software to control it) that can print continuously along curved surfaces.

AREVO is focused on production parts rather than prototyping. The company has produced a 3-D-printed fuel intake runner for automaker Polimotor fabricated from Solvay Specialty Polymers’ KetaSpire® polyetheretherketone (PEEK). The printed PEEK part weighs 50 percent of the original aluminum part. “We were able to prove that this technology works in an environment that is high in heat and requires chemical resistance,” says Bheda.