EMC TESTING: SHIELDING
Innovative EMC shielding
Powell Electronics CEO, Gary Evans, hopes to beat last minute EMC problems with his Europe-wide distribution deal
W
hile EMC should always be considered in the earlier stages of design, quite often it is left as a last-minute fix. To address this issue Powell
Electronics, the supplier of connectors and more for high-reliability applications including defence, aerospace and industrial, recently signed a pan- European franchise distribution agreement with P&P Technology, a European manufacturer of radio frequency and electromagnetic interference (RF & EMI) shielding products. P&P has products to fit most applications and can provide technical design support to help establish the most suitable method of fulfilling customer requirements. Included in P&P’s range are EMC gaskets and O-rings to fit all standard connector profiles, “honeycomb” EMI shielded vents and a range of conductive elastomers, including conductive particles in silicone and oriented wires in silicone, both designed to provide high EMI screening performance and excellent environmental protection.
CONNECTOR GASKETS P&P’s connector gaskets are available in a variety of materials, including various conductive silicones and plain environmental materials. P&P can assist clients when choosing a material to ensure it achieves all of the design requirements. Gaskets are cut using a precision automated CNC cutter, which can produce intricate and precision parts from just a technical drawing. Many of the gaskets are industry standard designs and are available according to MIL-C-81511, MIL- C-5015, MIL-C-38999 and MIL-C-26482
28 /// Testing & Test Houses /// March 2021
in industry-standard configurations including BN, BNC, D, WG, WR, IEC, UG, AN. However bespoke parts can be produced with a short turn-around time.
HONEYCOMB VENTS P&P has a strong market position in manufacturing EMI attenuated vents. It can offer products ranging from a basic single layer aluminium vent to a fully bespoke assembly including dust filters, gaskest and kickplates.
Vents are available in aluminium and can include two layers of honeycomb to increase performance. However, P&P also has high-performance vents manufactured from brass, steel and stainless steel. Each material has its specific properties and can be chosen to increase performance and/or environmental resilience. Honeycomb ventilation panels are usually supplied with gaskets in a ready- to-mount form. They can be fitted with protective “kick-plates” to protect the honeycomb material from accidental damage. Where they may be exposed to the elements, the vents can be fitted with “slant” honeycomb which provides a downward facing aperture, preventing the ingress of rainwater. This has the added benefit of directional airfl ow and increased attenuation due to the higher aspect-ratio of the cell structure.
ORIENTED WIRES IN SILICONE Oriented wires in silicone rubber combine excellent environmental protection with a high level of shielding effectiveness. Gaskets using this technology incorporate a matrix of vertically oriented wires which pierce both flat faces of the elastomer and provide around 100 contact points a square centimetre. Available materials include solid silicone and sponge silicone as well as fluoro-silicone (petro-chemical resistant), flame-retardant sponge silicone and flame-retardant solid silicone. These are produced in a block and then cut into sheets. Once a sheet is cut, P&P can supply the material in strips or can then cut the sheets into bespoke gasket profiles to meet the customer’s specifications. The benefits of oriented wires in silicone is that this approach offers the same performance as more traditional conductive particle loaded materials but is typically available on a shorter lead-time and at lower cost.
OTHER AVAILABLE APPROACHES In addition to its conductive elastomers and screened ventilation panels. P&P Technology offer an range of products including shielding windows, knitted wire meshes and gaskets, form-in-place gaskets, conductive fabric over foam, conductive
❱❱ Custom gasket profiles, insulation strips and honeycomb panels can be made from a variety of protective materials
contact finger stock, conductive adhesives, foil tape, cable glands and a choice of thermal materials. T&TH
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