Formable, reusable tooling achieves complex composite parts

Hawthorn Composites and Smart Tooling (Miamisburg, Ohio, U.S.) is exhibiting multiple displays — including a sub-scale trailing edge and tail booms — that demonstrate its ability to produce high-quality, complex composite parts with Smart Tooling.

The first display includes the inner and outer tail boom for the PAL-V Liberty flying car, made by Hawthorn Composites. The tail booms are complex geometry composite parts with trapped features and some high-tolerance requirements, developed using carbon fiber prepreg laid up on Smart Tools using laser guidance. Once layup was completed, the Smart Tools were placed into cure molds and cured in a conventional oven; Hawthorn says they act like bladders during cure and were pressurized to drive out air and compact the laminate during the cure cycle.

The second display is a sub-scale, multi-chamber composite trailing edge control surface that was a proof of concept (POC) project for Pilatus Aircraft Ltd. (Stans, Switzerland). Results led to Pilatus adopting a similar method of manufacture for making the control surfaces for its PC-24 business jet.

The small trailing edge chamber of the control surface has an acute, knife edge angle that would traditionally be made using a fabricated foam core. For this POC control surface, however, the trailing edge chamber and the adjoining chamber were made using Smart Tools. The fabrication included laying up carbon fiber prepreg into a floating lid cure mold, laying up prepreg onto the Smart Tools and placing them into the cure mold. Once completed, cure was performed via autoclave.

The Smart Tooling technology enables a rigid, reusable, elastic and reformable mandrel that can ease the burden of layup, while still enabling simplicity of extraction from the cured, trapped or complex geometry composite part.