Issue 41 Unmanned Systems Technology December/January 2022 PteroDynamics X-P4 l Sense & avoid l 4Front Robotics Cricket l Autonomous transport l NWFC-1500 fuel cell l DroneX report l OceanScout I Composites I DSEI 2021 report

88 Focus | Composites extendable printer arms on mobile gantries. Also, the company’s filament extrusion systems can weave copper wire into materials amid fibre lengths, resulting in hybrid composite PCB hull panels that could save enormous weight and volume. This solution could also be ideal for unmanned projects in space: reduced gravity could lessen the chances of mistakes and imperfections in additive deposition (and doing so in a vacuum reduces the chances of voids). And if additives can be sourced from asteroids or other worlds, it will no doubt save on the staggering costs of delivering satellites or rovers (or materials for printing them) off-world using rockets. That could also enable construction of vast, complex antennas for interplanetary comms and firmware updates, potentially allowing management of swarms of UGVs and UAVs for mapping, or even constructing bases on Mars and elsewhere in the Solar System. Quality control and testing Regardless of the manufacturing technique though, the quality of a part can be well-judged by testing its strength, elasticity, weight, thermal properties, void content and other qualities. ISO9001 and AS9100 certifications are widely acknowledged among composites suppliers to indicate quality, cost and delivery management performance. In composite supply chains this translates into measures for judging the geometries, thicknesses and performances of parts before and after they are finished. Computer measurement tools come in many varieties for examining pre- formed, pre-preg and cured composite parts, as well as moulds. Laser measurement scanners can show whether geometries and individual features have been produced to the required physical tolerances, and ultrasonic tools can test the strength, acoustics and porosity of a component. Both of these and many other scanning tools developed for similar purposes are expensive, but considerable r&d into automating such equipment for use in the composites world stands to bring down costs and raise standards for quality testing in the years ahead. Given the enormous range of shapes and features that composite parts can come in, tools and processes for gauging the physical properties of composites are hard to standardise. Most often, suppliers will construct custom jigs to hold a component steady in some dimensions, before applying stress or tension in others to validate its quality. Recycling While composites can give aerospace and automotive engineers far better strength-to-weight ratios than aluminium, they lag far behind in recyclability. The environmental impacts of that go without saying, but there is also an increasingly pronounced financial imperative to reduce material waste and save on the costs of sourcing them. Given the massive quantity of composites in use and newly made every year, widespread r&d into ‘clean’ methods of melting composites to recover the polymers and fibres are ongoing; tangible results of that can be expected over the next 10-20 years. For now though, there are two primary approaches composites suppliers take to recycling. One of these is effectively ‘downcycling’. Many unmanned vehicle OEMs will receive parts that do not quite fit the tolerances needed for their platforms, sometimes even if tests for weight, geometry and so on have been passed following production. They could send them to a landfill or ship them back to the supplier, some of whom will then sell the part to a medical or industrial user, who simply needs some spare boards or panels. OEMs adopting this practice could therefore recoup some of their purchasing costs and reduce the harmful emissions associated with their orders. However, composite suppliers will also amass considerable offcuts of pre-preg or dry fabric that are too small to be individually cut into panels or surfaces for other applications. A novel means of re-using these scraps, developed by Lamborghini and Callaway Golf December/January 2022 | Unmanned Systems Technology Filament and additive extrusion from robotic arms can manufacture large, complicated composite PCB hull pieces (Courtesy of Orbital Composites)