{"id":1286,"date":"2026-02-25T17:17:46","date_gmt":"2026-02-25T09:17:46","guid":{"rendered":"https:\/\/jkrglo.com\/?page_id=1286"},"modified":"2026-06-25T15:57:46","modified_gmt":"2026-06-25T07:57:46","slug":"fr4-pcb","status":"publish","type":"page","link":"https:\/\/jkrglo.com\/de\/fr4-pcb\/","title":{"rendered":"FR4 PCB"},"content":{"rendered":"
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FR4 PCB<\/h1>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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HOME<\/a><\/span><\/span><\/p>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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What is an FR4 PCB?<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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Flame Retardant 4, or FR4, is a material grade used in PCB manufacturing. It is made of fibreglass and “4” represents the UL94 V-0 flammability standard (it must self-extinguish after being ignited). Fibreglass reinforced woven glass fibre and epoxy resin with makes it excellent for electrically insulated applications. FR4 is a widely used material due to its low cost and high reliability.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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FR4 Material Overview<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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FR4 represents flame-retardant grade 4 glass-reinforced epoxy laminate. The material’s dielectric constant and dissipation factor (loss tangent) are moderate. FR4 can be used in low-speed and high-power applications, making it the first choice for many hobbyists. This makes it suitable for general-purpose electronic designs. Dielectric constant: around 4.5 at 1MHz (moderate). Loss tangent: around 0.02 at 1MHz (moderate). The glass transition temperature (Tg) determines how the material behaves under heat. It is one of the most important thermal properties in the classification of FR4 materials.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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FR4 comes in three different temperature ranges:<\/div>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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Low Tg (130\u2013140\u00b0C)<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Standard Tg (150\u2013160\u00b0C)<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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High Tg (>170\u00b0C)<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Structure and Properties of FR4<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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FR-4 is a composite material used as the substrate in PCBs. Its structure is made from:<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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1. Woven Fiberglass Cloth (E-glass fibers):<\/strong><\/span>\u00a0<\/strong>Fibreglass provides higher mechanical strength and appears as a fine woven fabric inside the laminate.<\/div>
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2. Epoxy Resin (flame-retardant, brominated):<\/strong><\/span>\u00a0<\/strong>Epoxy acts as the matrix, binding the fiberglass together and providing excellent electrical insulation and thermal resistance.<\/div>
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3. Copper Foil (in PCBs):<\/strong><\/span>\u00a0Copper foil layers are used to make tracks and are laminated onto FR-4 using heat and pressure.<\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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Benefits of FR4 PCB Material<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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Cost-Effective and Widely Available<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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FR-4 is affordable compared to advanced laminates like Rogers. Its low cost makes it popular and the industry standard for most applications. It is globally available, making it easy to source for large production volumes.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Good Mechanical Strength<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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The woven fiberglass provides higher tensile strength, making it more resistant to warping, bending, and mechanical stress.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Reliable Electrical Insulation<\/h3>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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Due to a moderate dielectric constant, it is excellent for low-frequency and higher-power applications. Additionally, the epoxy-fiberglass structure offers higher signal isolation.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Benefits of FR4 PCB Material<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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1. Signal Integrity and Impedance Control <\/h3><\/span>\n\t\t\t\t\t\t\t\n\t\t\t<\/path><\/svg><\/span>\n\t\t\t<\/path><\/svg><\/span>\n\t\t<\/span>\n\n\t\t\t\t\t\t<\/summary>\n\t\t\t\t
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Thicker FR-4<\/span><\/strong>\u00a0increases the dielectric spacing, which raises impedance by introducing parasitic components. FR-4 thickness can be adjusted to control impedance for different circuit applications.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t

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Thinner FR-4<\/span><\/strong>\u00a0has a smaller dielectric spacing between copper layers, which lowers the impedance of traces. However, the higher dielectric loss of FR-4 limits performance above a few GHz regardless of thickness.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/details>\n\t\t\t\t\t\t

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2. Thermal Management <\/h3><\/span>\n\t\t\t\t\t\t\t\n\t\t\t<\/path><\/svg><\/span>\n\t\t\t<\/path><\/svg><\/span>\n\t\t<\/span>\n\n\t\t\t\t\t\t<\/summary>\n\t\t\t\t
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Thicker FR-4<\/span><\/strong>\u00a0offers improved heat spreading and higher thermal capacity, which helps reduce the risk of localized overheating.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t

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Thinner FR-4<\/span><\/strong>\u00a0has limited heat-spreading capability on high-power boards, making it more susceptible to hot spots.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/details>\n\t\t\t\t\t\t

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3. Mechanical Stability <\/h3><\/span>\n\t\t\t\t\t\t\t\n\t\t\t<\/path><\/svg><\/span>\n\t\t\t<\/path><\/svg><\/span>\n\t\t<\/span>\n\n\t\t\t\t\t\t<\/summary>\n\t\t\t\t
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Thicker boards<\/span><\/strong>\u00a0are more rigid and resistant to bending, which makes FR4 more suitable for mechanically stressed assemblies.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t

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Thinner boards<\/span><\/strong>\u00a0are more flexible and lightweight, making them ideal for compact devices but more prone to warping.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/details>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Common Applications of FR4 PCBs<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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1. Consumer Electronics <\/h3><\/span>\n\t\t\t\t\t\t\t\n\t\t\t<\/path><\/svg><\/span>\n\t\t\t<\/path><\/svg><\/span>\n\t\t<\/span>\n\n\t\t\t\t\t\t<\/summary>\n\t\t\t\t
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FR4 PCBs balance cost and strength for everyday electronic devices. From smartphones to wearables, FR-4 provides durable and reliable PCB solutions.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/details>\n\t\t\t\t\t\t

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2. Industrial Control Systems <\/h3><\/span>\n\t\t\t\t\t\t\t\n\t\t\t<\/path><\/svg><\/span>\n\t\t\t<\/path><\/svg><\/span>\n\t\t<\/span>\n\n\t\t\t\t\t\t<\/summary>\n\t\t\t\t
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Control systems, power supplies, and automation boards often use thicker FR-4 laminates. FR4 PCB for mechanical rigidity and ability to withstand moderate thermal cycling.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/details>\n\t\t\t\t\t\t

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3. Automotive Electronics <\/h3><\/span>\n\t\t\t\t\t\t\t\n\t\t\t<\/path><\/svg><\/span>\n\t\t\t<\/path><\/svg><\/span>\n\t\t<\/span>\n\n\t\t\t\t\t\t<\/summary>\n\t\t\t\t
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Instrument clusters, infotainment units, and sensor modules frequently use FR-4 PCBs. FR4 PCBs provide stable performance under vibration and moderate heat.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/details>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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JKRGLO FR4 PCB Manufacturing Capabilities<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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FR4 PCB Manufacturing Capabilities <\/h3><\/span>\n\t\t\t\t\t\t\t\n\t\t\t<\/path><\/svg><\/span>\n\t\t\t<\/path><\/svg><\/span>\n\t\t<\/span>\n\n\t\t\t\t\t\t<\/summary>\n\t\t\t\t
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\n \n\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n
\n Features <\/td>\n \n Capabilities <\/td>\n <\/tr>\n
\n Layer count <\/td>\n \n 1, 2, 4, 6, ...32 layers <\/td>\n <\/tr>\n
\n Controlled Impedance <\/td>\n \n 4\/6\/8\/10\/12\/14\/16\/18\/20\/...\/32 layers <\/td>\n <\/tr>\n
\n Impedance Tolerance <\/td>\n \n \u00b110% (\u00b15\u03a9 if value \u2264 50\u03a9) <\/td>\n <\/tr>\n
\n Maximum Dimensions <\/td>\n \n 670 \u00d7 600mm (Thickness \u2265 0.8mm); <\/td>\n <\/tr>\n
\n 500 \u00d7 600mm (Thickness < 0.8mm); <\/td>\n <\/tr>\n
\n 2-layer reaches 1020 \u00d7 600mm. <\/td>\n <\/tr>\n
\n Minimum Dimensions <\/td>\n \n 3 \u00d7 3mm; 70 \u00d7 70 for V-cut panel <\/td>\n <\/tr>\n
\n Outer Copper Thickness <\/td>\n \n 1oz, 2oz (2.5oz, 3.5oz, 4.5oz for 2-layer) <\/td>\n <\/tr>\n
\n Inner Copper Thickness <\/td>\n \n 0.5 oz, 1 oz, 2 oz <\/td>\n <\/tr>\n
\n Surface finish <\/td>\n \n HASL (leaded \/ lead-free), ENIG(1u\" \/ 2u\") <\/td>\n <\/tr>\n
\n Minimum Via Hole\/Diameter <\/td>\n \n 0.15mm \/ 0.25mm <\/td>\n <\/tr>\n
\n Hole Size Tolerance <\/td>\n \n \u2460 Plated: Through-holes: +0.13 \/ -0.08mm ; Press-fit holes\uff1a\u00b10.05mm <\/td>\n <\/tr>\n
\n \u2461 Non-plated: \u00b10.2mm <\/td>\n <\/tr>\n
\n Minimum Plated Slots <\/td>\n \n 0.5mm <\/td>\n <\/tr>\n
\n Minimum Non-Plated Slots <\/td>\n \n 1.0mm <\/td>\n <\/tr>\n
\n Plated Edges <\/td>\n \n Available with PCB size 10 \u00d7 10mm, thickness: 0.6mm. ENIG is required. <\/td>\n <\/tr>\n
\n Blind Slot <\/td>\n \n Available in 2-32 layer boards with a thickness of \u2265 0.8mm. <\/td>\n <\/tr>\n
\n Countersink Hole <\/td>\n \n Available in 2-32 layer boards with a thickness of \u2265 0.6mm.\n\nSupported countersink angle: 90\u00b0\/135\u00b0 <\/td>\n <\/tr>\n
\n Backdrill <\/td>\n \n Available in 4-32 layer boards with a thickness of \u2265 0.8mm.\n\nHoles will be epoxy resin filled after backdrilling. <\/td>\n <\/tr>\n
\n Castellated Holes <\/td>\n \n Available with PCB size 10 \u00d7 10mm. <\/td>\n <\/tr>\n
\n Minimum Track Width and Spacing <\/td>\n \n \u2460 1oz: 0.10 \/ 0.10mm (4 \/ 4mil) for 1\/2-layer ; 0.09 \/ 0.09mm (3.5 \/ 3.5mil) for muliti-layer <\/td>\n <\/tr>\n
\n \u2461 2oz: 0.16 \/ 0.16mm (6.5 \/ 6.5mil) for 1\/2-layer; 0.16 \/ 0.20mm (6.5 \/ 8mil) for multi-layer <\/td>\n <\/tr>\n
\n Minimum BGA Pad Diameter <\/td>\n \n 0.25mm <\/td>\n <\/tr>\n
\n Gold Fingers Bevelling <\/td>\n \n 30\u00b0 or 45\u00b0 <\/td>\n <\/tr>\n <\/table>\n<\/div>