Parameter Characteristics of FR-4 PCB

FR-4 epoxy glass fiber cloth substrate is a class of substrate with epoxy resin as a binder and electronic grade glass fiber cloth as reinforcing material. Its bonding sheet and the inner core of the thin copper-clad laminate, make the production of multilayer printed circuit boards an important substrate. FR4 is a flame-resistant material grade code, on behalf of meaning the resin material must be able to self-extinguish after the combustion state of a material specification, it is not a material name, but a material grade, so the general circuit boards used in the FR4 level of material on a very large number of types, but the majority are FR4 is a composite material made of epoxy resin plus fillers and glass fibers. cutting fr4

FR4 material is characterized by stable electrical insulation properties, good flatness, smooth surface, no pits, and thickness tolerance standards, suitable for application in high-performance electronic insulation requirements of the product, such as FPC reinforcement board, PCB drilling pads, fiberglass dielectrics, potentiometer carbon film printed fiberglass panels, precision vernier gears (wafer milling), precision test panels, electrical (electrical) equipment, insulating bracing spacer, insulating pads, Transformer insulation boards, motor insulation parts, grinding gears, electronic switch insulation boards, etc. cutting fr4

FR4 Material Grade
(1) R-4 A1 grade copper-clad laminates: This grade is mainly used in the military, communications, computers, digital circuits, industrial instrumentation, automotive circuits, and other electronic products. The quality of this series of products has completely reached the world-class level, the highest grade, and the best performance products.
(2) FR-4 A2 grade copper-clad laminates: this level is mainly used for ordinary computers, instruments and meters, advanced home appliances, and general electronic products. This series of copper cladding boards is widely used, and the performance indicators can meet the needs of general industrial electronic products. There is a very good price-performance ratio. Enable customers to effectively improve price competitiveness.
(3) FR-4 A3 level of copper-clad laminate: This level of copper-clad laminate is usually for the home appliance industry, computer peripheral products, and general electronic products (such as toys, calculators, game consoles, etc.) the development and production of FR-4 products. Characterized by its performance to meet the requirements of the premise, the price is very competitive.
(4) FR-4 A4 grade copper-clad laminate: this level of plate is FR-4 copper-clad low-end materials. But the performance indicators can still meet the needs of ordinary home appliances, computers, and general electronic products, its price is the most competitive, and the performance-price ratio is also quite excellent.
(5) FR-4 B-class copper-clad laminate: this level of plate is relatively poor, quality stability is poor, but the price is the lowest, does not apply to a larger area of the circuit board products, generally applicable to the size of 100mmX200mm products. cutting fr4

FR4 PCB DK, DF, and TG values
The dielectric constant (Dk, ε, Er) determines the speed of propagation of electrical signals in the medium. The speed of electrical signal propagation is inversely proportional to the square root of the dielectric constant. The lower the dielectric constant, the faster the signal is transmitted. Generally used FR4 copper-clad sheet, relative to the air dielectric constant is 4.2-4.7. This dielectric constant will change with temperature, in the temperature range of 0-70 degrees Celsius, the maximum range of change can reach 20%. A change in dielectric constant will result in a 10% change in line delay, the higher the temperature, the greater the delay. The dielectric constant will also change with the frequency of the signal, the higher the frequency the smaller the dielectric constant, and the general design of the dielectric constant of the classic value of 4.4.

FR4 sheet dielectric loss: insulating materials in the electric field, due to dielectric conductivity and dielectric polarization of the hysteresis effect, the energy loss caused by its internal. Also called dielectric loss, referred to as dielectric loss. Under the action of an alternating electric field, the residual angle δ of the angle between the current phase and voltage phase flowing in the dielectric (power factor angle Φ) is called the dielectric loss angle.FR4 sheet dielectric loss is generally 0.02, and the dielectric loss will increase with the increase of frequency. cutting fr4

TG value: also known as the glass transition temperature, generally 130 ℃, 140 ℃, 150 ℃, 170 ℃.

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