2 min. Read
Executive Summary
Silver has long been the filler of choice within conductive paints used for electromagnetic interference (EMI) shielding protection when working with critical performance applications such as military, automotive and aerospace.
Sustained increases in cost have already prompted some designers and sourcing teams to search for alternatives. Escalating silver costs are significantly impacting manufacturing budgets. Within many EMI shielding applications, conductive paints are sometimes specified based on historical precedent rather than actual requirement. Advances in technology have resulted in the next generation of EMI shielding paints, featuring unique silver flake technology. As a result, a thinner coverage of paint is possible, offering comparable performance to the traditional product, but most importantly, a 30% cost saving. As silver prices continue to rise, perhaps it is time to revisit, and challenge original assumptions. A shielding material may have become the preferred material, but today there are alternatives to explore with savings that would certainly be appreciated by the purchasing team in the overall cost of the bill of materials.
Recent data suggests that in a significant number of plastic or metal enclosure applications, comparable performance can be achieved with reduced paint thickness. Inevitably this leads to the question: Are current solutions optimised for performance or simply specified to exceed it?
The Cost Challenge of Silver-Based Paints
The role of EMI Shielding is essential for many applications to provide shielding protection, ensure regulatory compliance and protect sensitive components from external interference. The role of silver as filler within the paint is as a result of superior shielding performance across a wide frequency range. The cost of silver has been increasing exponentially over recent months, pushing upward pressure toward purchasing teams, and resultant reduction of margins. Consequently, there is pressure to redesign or re-qualify materials. In many cases, the existing shielding solutions may be over engineered based on shielding targets. Specifically, material specifications for coating thickness may be more than what is necessary to achieve compliance levels and not optimised for cost-performance balance.
New Conductive Paint Technology
A practical alternative to the traditional silver filler does exist. MG Chemicals have developed the next generation product 842ARL, containing unique silver flake technology which can be applied at only 25µm, yet offering comparable performance to conventional silver shielding products at a much lower price point.
Remember: maximum performance does not always equal optimal design. Engineers frequently design with safety margins that exceed actual requirements. It’s time to challenge those original assumptions.
The differentiator: this paint achieves comparable shielding of 60-100 dB across a wide frequency range with less material.
Comparison of Legacy Conductive Coating & 842ARL
The shielding data presented in figure 1 shows that while legacy coatings provide more attenuation, the 842ARL still provides exceptional performance across a broad frequency range. The overall saving per unit is 30% when compared to legacy products at current prices.
Ancillary to shielding performance, the 842ARL also boasts an exceptionally low resistivity of 7.5×10-5 Ωcm. The highly engineered flake coupled with the acrylic polymer system has exceptional resistance to weathering, showing no loss in conductivity after 7 days of salt fog testing per ASTM B117.
Rethinking the Use of Legacy Materials with Sudden Costing Constraints
Is it necessary to achieve maximum conductivity, or simply have sufficient conductivity to meet the required shielding target? Our findings suggest that with some critical and non-critical applications, EMI shielding levels are not only met, but exceed required thresholds. Therefore, a change from the shielding product initially specified into the design may not compromise performance.
Remember: in many cases, the limiting factor in EMI shielding performance may not be conductivity – but assumptions. New financial realities will force product designers to rethink material choices and accept trade-offs that place more consideration on cost balance. To help you navigate which conductive coatings are best suited for your application, please contact us for technical assistance.
