The Brunel Composite Centre (BCC) successfully delivered its first EPSRC Future Composites Manufacturing HUB funded project on microwave heating through embedded waveguides for composites manufacturing.
The project started in February 2018 and investigated the feasibility of utilising MW heating for composites manufacturing without the need of a dedicated MW Oven.
The initial concept was wires with slots that could act as MW applicators (waveguides). However, this solution did not produce an acceptable thermal profile, as the local temperature variations were too high. The simple configurations tried by the BCC improved the local variations, but more work is needed to conclusively evaluate the idea and its practicality.
A different approach, consisting of MW applicators that can be realised as printed circuit boards (PCBs) that can be slotted inside tooling, was then tried. The design of the boards can follow the heating requirement of the composite shape and size. The concept was validated by producing a number of composite laminates that were of similar quality to laminates produced in a convection oven.
Figure 1: Monopole array (top) and fractal (bottom) radiating element designs. A visualization of the resulting loss distribution derived with Ansys High Frequency Field Solver (HFSS) can be seen on the right for the two designs
Figure 2: Fractal antenna used as a microwave applicator. The antenna feed where the coaxial cable is coupled is visible at the bottom of the photo.
BCC is a strategic partnership between Brunel University London and TWI and part of the TWI Innovation network. The Centre will create a shared research and technology capability specialising in novel composites processing and joining technologies applied to industrial environments.