{"id":2567,"date":"2026-06-17T16:52:27","date_gmt":"2026-06-17T08:52:27","guid":{"rendered":"https:\/\/www.jcinjectionmolding.com\/?p=2567"},"modified":"2026-07-01T09:23:28","modified_gmt":"2026-07-01T01:23:28","slug":"emi-rfi-shielding","status":"publish","type":"process","link":"https:\/\/www.jcinjectionmolding.com\/ja\/service\/emi-rfi-shielding\/","title":{"rendered":"EMI\/RFI Shielding"},"content":{"rendered":"
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EMI\/RFI Shielding Coatings & Attenuation Effectiveness<\/h2>\n

Raw thermoplastics are naturally transparent to electromagnetic waves. Achieving superior shielding effectiveness requires selecting the correct conductive coating chemistry:<\/p>\n\n\n\n\n\n\n\n
Shielding Coating Type<\/th>\nConductive Metallic Pigment<\/th>\nTypical Sheet Resistance<\/th>\nShielding Effectiveness (SE Range)<\/th>\n<\/tr>\n<\/thead>\n
Nickel Coating<\/td>\nHigh-Purity Carbonyl Nickel Powder<\/td>\n< 1.5 Ohm\/sq<\/td>\n40 – 55 dB (Good). Standard industrial grade, cost-effective, highly resistant to oxidation. Used for household appliance housings and standard monitors.<\/td>\n<\/tr>\n
Copper \/ Silver-Copper<\/td>\nSilver-Plated Copper Flakes<\/td>\n< 0.15 Ohm\/sq<\/td>\n60 – 75 dB (Excellent). Outstanding electrical conductivity, high environmental stability. Perfect for medical diagnostics and automotive electronics.<\/td>\n<\/tr>\n
Pure Silver Varnish<\/td>\nPremium Micro-Fine Silver Flakes<\/td>\n< 0.015 Ohm\/sq<\/td>\n75 – 90+ dB (Ultimate). Extremely high attenuation in minimal thicknesses. Specified for military sensors, avionics, and sensitive telemetry.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/section>\n

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Substrate Prep, Masking Tolerances & Quality Testing<\/h2>\n

Conductive coatings must remain restricted to interior part faces, demanding precise masking tooling and rigid adhesion testing:<\/p>\n\n\n\n\n\n\n\n
Quality Control Parameter<\/th>\nJucheng Precision Specification<\/th>\nEngineering Adhesiveness & Compliance<\/th>\n<\/tr>\n<\/thead>\n
Selective Masking Tolerance<\/td>\n\u00b10.15 mm Boundary Precision<\/td>\nEnsures conductive overspray does not escape to exterior cosmetic surfaces or interfere with snap-fits and ultrasonic welds.<\/td>\n<\/tr>\n
Coating Adhesion<\/td>\nASTM D3359 Cross-Hatch 5B Rating<\/td>\nGuarantees zero paint peeling or flaking over long-term thermal cycling, preventing loose metallic chips from short-circuiting internal PCBs.<\/td>\n<\/tr>\n
Shielding Testing Standard<\/td>\nASTM D4935 \/ IEEE 299 Compliant<\/td>\nEnsures rigorous RF attenuation testing inside electromagnetic chambers across frequencies ranging from 10 MHz to 10 GHz.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/section>\n

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Selective Masking & Conductive Adhesion Matrix<\/h2>\n

Creating a reliable and high-attenuation electrical shielding barrier inside complex plastic housings demands high-precision tooling and surface pre-treatments:<\/p>\n

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Custom Selective Masking Fixtures<\/p>\n

Conductive paints must be restricted to non-visible interior cavities. Any overspray on parting lines or screw-boss faces can ruin cosmetics or cause electrical short-circuits. Jucheng’s tooling division uses 5-axis CNC machines to mill customized metal or silicone masking fixtures. These tools secure a tight, physical seal over mating boundaries, maintaining \u00b10.15mm edge tolerances.<\/p>\n<\/div>\n

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Eliminating Peeling (Silicone-Free Mold Release Policy)<\/p>\n

If conductive paint peels off, loose metallic flakes can drift inside the enclosure and short-circuit electronic components. To secure a permanent 5B cross-hatch rating on ABS\/PC-ABS substrates, we strictly enforce a silicone-free mold release policy during injection molding, ensuring all interior part walls are chemically pristine and clean.<\/p>\n<\/div>\n

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Thickness Uniformity & Sheet Resistance Controls<\/p>\n

Shielding effectiveness relies on maintaining a continuous conductive path. Any variation in paint thickness can create high-resistance cold spots. We utilize air-atomized spray nozzles and automatic rotation jigs to achieve highly uniform thickness (25\u201335 \u00b5m), keeping sheet resistance strictly below 1.0 Ohm\/sq.<\/p>\n<\/div>\n<\/div>\n<\/section>\n<\/div>","protected":false},"excerpt":{"rendered":"

EMI\/RFI Shielding Coatings & Attenuation Effectiveness Raw thermoplastics are naturally transparent to electromagnetic waves. Achieving superior shielding effectiveness requires selecting the correct conductive coating chemistry: Shielding Coating Type Conductive Metallic Pigment Typical Sheet Resistance Shielding Effectiveness (SE Range) Nickel Coating High-Purity Carbonyl Nickel Powder < 1.5 Ohm\/sq 40 – 55 dB (Good). Standard industrial grade, cost-effective, highly resistant to oxidation. Used for household appliance housings and standard monitors. Copper \/ Silver-Copper Silver-Plated Copper Flakes < 0.15 Ohm\/sq 60 – 75 dB (Excellent). Outstanding electrical conductivity, high environmental stability. Perfect for medical diagnostics and automotive electronics. Pure Silver Varnish Premium Micro-Fine Silver Flakes < 0.015 Ohm\/sq 75 – 90+ dB (Ultimate). […]<\/p>\n","protected":false},"featured_media":2589,"template":"","process_category":[25],"class_list":["post-2567","process","type-process","status-publish","has-post-thumbnail","hentry","process_category-surface-finishes"],"_links":{"self":[{"href":"https:\/\/www.jcinjectionmolding.com\/ja\/wp-json\/wp\/v2\/process\/2567","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.jcinjectionmolding.com\/ja\/wp-json\/wp\/v2\/process"}],"about":[{"href":"https:\/\/www.jcinjectionmolding.com\/ja\/wp-json\/wp\/v2\/types\/process"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.jcinjectionmolding.com\/ja\/wp-json\/wp\/v2\/media\/2589"}],"wp:attachment":[{"href":"https:\/\/www.jcinjectionmolding.com\/ja\/wp-json\/wp\/v2\/media?parent=2567"}],"wp:term":[{"taxonomy":"process_category","embeddable":true,"href":"https:\/\/www.jcinjectionmolding.com\/ja\/wp-json\/wp\/v2\/process_category?post=2567"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}