04 September 2009
04 September 2009
Composiflex has recently been approached by a number of military electronics equipment manufacturers who are looking to improve their range of man-portable devices.
Electromagnetic interference (EMI) shielding, thermal management, and radiolucence are among the design requirements of military and avionics applications. Additional factors such as impact and abrasion resistance, which are common problems in portable use.
One of the main challenges was to devise an effective combination of fibre, resin, lay-up, and processing method to address MIL-STD 810 drop test requirements. Although fibre-reinforced polymer composites are not inherently impact resistant, Composiflex say they have produced test samples which have survived a 48” drop test, under various loads, with positive results - no cracking or visible damage of any kind. Testing continues with samples representative of enclosure corners and edges.
Several methods of achieving EMI shielding have been successfully used with composite materials. The actual material and process selected varies with the relevant frequency range, the required attenuation, and the geometric features of the enclosure. Options include plating, conductive paints, foils, meshes, and specialty composite materials.
Thermal management is not a consideration for every application. When it is a factor, the topic requires more specialized attention than the other aspects of composite enclosure design. Methods chosen are dependent upon the heat gradient and the chosen mode(s) of heat transfer. In order to address this aspect of electronics enclosure design, Composiflex has partnered with an expert in thermal management for composite structures.
Composiflex is also partnering with a local electronics contract manufacturer, as well as a manufacturer of elastomeric shock mounts. A company spokesperson said that these alliances will allow Composiflex to provide more value-added services to customers who prefer to receive complete sub-assemblies, including some level of electronic component.
By using fibre-reinforced polymer enclosures, customers and manufacturers hope to gain significant weight reductions not easily achieved using more conventional engineering materials, which will improve portability of the finished product.