Thermoplastics Break Out In 3D-Printed Autoclavable Tools

Additive Engineering Solutions of Akron Ohio has successfully printed autoclavable composite molding tools in 16 different thermoplastics using a Big Area Additive Manufacturing (BAAM) machine from Cincinnati Inc.

AES was formed two years ago as a spinoff from a metal-forming contract manufacturer. The company’s focus is on tool and mold production and says it can process almost all materials in pellet form that can be used in an injection molding machine.

“With our BAAM, we’re able to print parts at a scale of 12ft long, 5.5ft wide, and 6ft tall,” says Andrew Bader, a cofounder. “The pieces we print can also be bonded together to build even larger parts.”

The concept of printing autoclavable tools for the aircraft and other industries was demonstrated last year by a consortium headed by the Deposition Science and Technology group at the Oak Ridge National Laboratory in Knoxville, Tennessee. Digital tool manufacturing reduces costs and leadtimes. Tools can be printed and machined in hours, compared to an average lead time of 14 weeks for conventional production methods. The tools were tested in Boeing autoclaves.

Vlastimil Kunc, who heads the research effort at ORNL, told The Molding Blog that there are several commercial sites using or testing polyphenylene sulfide and other materials for 350ºF cure cycle applications.

“Cincinnati Incorporated has printed in a variety of high temperature materials on our BAAM machine,” says Rick Neff, the company’s additive manufacturing products and sales manager. “We have used PPS and PEI both with carbon fiber reinforcing. There are seven other CI customers (besides Additive Engineering Solutions) using BAAM either for materials research or tooling applications. 

Techmer PM collaborated with ORNL and BASF to design two new, 3D-printable, engineering thermoplastic compounds – Electrafil PPS 3DP and Electrafil PPSU 3DP– for high-temperature autoclave tooling applications. They are provided in pellet form. Previous high-performance composites lacked adequate thermal capabilities.

Tom Drye, Techmer’s vice president for emerging markets and innovation, said that both compounds are optimized to withstand a 350°F, 100 psi autoclave cycle with minimal dimensional changes (CTE) through the cure cycle of the printed tools and parts. The composition and rheology of each have been developed for deposition rates exceeding 50 pounds/hour through a 1-inch extruder. He said the compounds are designed to tolerate process changes during long build times and extended residence times.

The materials also are fully recyclable, according to Drye. The molded parts, which can exceed 900 pounds each, often go through several iterations.

Drye told The Molding Blog in an email: “These new engineered plastic tools will replace expensive metal tooling used to make pre-preg composite parts used in aerospace, automotive, and other demanding applications such as: engine cowlings, interior cabin panels, trim tools, liftbacks, etc.  Major OEM’s are investing heavily into this technology to reduce costs, increase design freedom, and improve speed to market.”

A 3D-printed thermoplastic mold manufactured at ORNL withstood testing in an industrial autoclave. The concept is now being widely adopted. (ORNL)

About Doug Smock

Former Chief Editor at Plastics World and Senior Technical Editor Design News
Additive manufacturing, Aircraft, Engineering Thermoplastics, Molds & Moldmaking, North America, Polyphenylene sulfide , , ,

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