ELECTRICAL AND ELECTRONIC | INNOVATION As electronic
components become smaller and more
complex, the challenges
increase for developers of engineering thermoplastics. Peter Mapleston finds out about new processes and
offerings from materials suppliers
Over-moulding electronics: making melts flow better
The need for efficient low-pressure encapsulation of electronics has never been as great as it is today. The Internet of Things (IoT) depends on a founda- tion of sensors and associated electronic connec- tions and components to support all sorts of devices in the home, at work, and on the move. This trend has also led to increased network connectivity demands for data and power cables and connectors that function in the harshest environments. Sensors are also increasingly used in medical diagnostics and wearables. In a large number of these applications, the electronics need to be embedded in plastics to cushion them and protect them from the local environment. The trick when trying to encapsulate electronics is to ensure that these often delicate elements are not moved or damaged as liquid polymer flows over them. It also helps if the process can be carried out quickly and economically. It’s rather like squaring a circle. But there are plenty of equipment and materials technology developers trying to make it happen. Quite a lot of the work going on is at the fringes of injection moulding, where it overlaps with other technologies such as extrusion, casting, and even additive manufacturing. But what matters in the end is that the customer, whether they be producing cars or smart phones or
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robots, has a piece of electronics that works well, for a long time, often in difficult environments, at a price that they can afford. X2F is a process developed by the company of the same name, based in Loveland, Colarado, USA, founded in 2014 by Rick Fitzpatrick (CTO) and Ron Leach (Chairman). X2F stands for Extrude to Fill. This gives an idea of how the process works, since it is not traditional injection moulding. The com- pany says its process enables melt to move into a mould cavity without the pressures common to injection molding. But it is different from low pressure moulding, and it is not a traditional potting process either. The company says its technology “leverages
controlled viscosity and a patented ‘pulse-packing’ approach to create high-value components for a variety of industries.” X2F says the process can achieve complex product geometries with im- proved operational efficiencies. Machines use a multizone screw that acts as a pump, delivering material that’s been brought to its melt tempera- ture in a static state. According to the developers, the process
“dramatically” reduces material degradation and moulded-in stress quite common in conventional moulding technologies. It is also said to offer faster development from prototyping to production-
October 2021 | INJECTION WORLD 47
Main image: Fraunhofer IPA demonstrator of customised sensor in which the PBT casing is 3D printed
IMAGE: FRAUNHOFER IPA
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