What is fr4

At first, fr4 material, this is the abbreviation of glass fiber cloth, it is a kind of circuit board raw material and substrate, flame resistant material grade code, which means that the resin material through the burning state must be able to self-extinguishing a material specification. We use them most commonly in PCB (printed circuit board), the general single, double sides and multilayer PCB circuit board ! Because of its high strength and flame resistance, most circuit boards will choose FR-4 as the base material.

What is PCB and its composition?

Secondly, PCB is the abbreviation of the English Circuit Board, Printed Circuit Board in Chinese, also known as printed circuit board, printed circuit board, is an important electronic component. It is the provider of electrical connection of electronic components.

A PCB starts with the most basic unit: the base, which consists of several layers, each of which plays an important role in the function of the final PCB. These alternating layers include:

  • Firstly, Substrate: This is the base material of the PCB. It makes the PCB rigid.
  • Secondly, Copper: Add a thin layer of conductive copper foil to each functional face of the PCB — on one side if single-sided PCB, or on both sides if double-sided PCB. This is the copper wiring layer.
  • Thirdly, Solder resistance layer: The top of the copper layer is the solder resistance layer, which gives each PCB its characteristic green color. It puts the copper trace in inadvertent contact with other conductive materials that may cause a short circuit. In other words, the solder keeps everything in place. The holes in the solder resistance layer are where we apply the solder attach the components to the circuit board. The solder resistance layer is a key step in the smooth manufacture of PCBA, as it prevents welding from occurring on unwanted components and prevents short circuits.
  • Finally, Screen printing: The white screen printing is the final layer on the PCB board. This layer adds labels to the PCB in the form of characters and symbols. This helps indicate the functionality of each component on the board.

PCB varies according to its substrate material, high-frequency microwave plate, metal substrate, aluminum substrate, iron substrate, copper substrate, double panel and multi-layer board.

The circuit is used as a tool for conduction between the original, and another large copper surface will be designed as a grounding and power supply layer in the design. The circuit and the drawing surface are made simultaneously. The wiring density is high, the volume is small, the weight is light, is conducive to the electronic equipment miniaturization.

The substrate of the board itself is made of insulating and insulating material, which is not easy to bend. The thin wire material that can be seen on the surface is copper foil. Originally, the copper foil is covered on the whole board, but in the manufacturing process, the central part is etched away, and the remaining part becomes a network of thin wires.

Advantages and characteristics of fr4.

Thirdly, we make common single -, double-side and multilayer PCB boards with FR-4. The FR in FR-4 stands for flame retardant, and the number 4 distinguishes this material from other materials in this category. FR-4 is fiberglass reinforced epoxy laminate that looks like thin woven cloth boards. The term FR-4 also stands for the grade used to make these laminates. Fiberglass construction provides structural stability to the material. The fiberglass layer is covered with a flame retardant epoxy resin. This brings durability and strong mechanical properties to the material. All of these properties have made the FR-4 printed circuit board popular among electronics contract manufacturers.

Its technical characteristics mainly lie in:

Electrical insulation, stable, good flatness, smooth surface, no pits, thickness tolerance standard, suitable for the application of high performance electronic insulation requirements of products, Such as FPC reinforcement board, PCB drilling pad, glass fiber mesons, potentiometer carbon film printed glass fiberboard, precision travel star gear (wafer grinding), precision test plate, electrical (electrical) equipment insulation bracket partition, insulation pad, transformer insulation board, motor insulation parts, grinding gear, electronic switch insulation board, etc.

Overall, now we widely use FR-4 plate in military, communications, computers, digital circuits, industrial instruments, automotive circuits and other electronic products, the performance indicators can meet the needs of general industrial electronic products. There is a good price performance ratio.

For example: industrial battery circuit boards

Finally, let’s summarize what fr4 material is and its characteristics:

  1. FR4 is a code for the grade of fire-resistant materials, which means that the resin material must be able to self-extinguish after burning.
  2. FR4 is not a material name, but a material grade, so the current general circuit board used FR4 grade materials are very many kinds, but most of them are the so-called four function epoxy resin plus filler and glass fiber composite materials.
  3. FR4 thickness specification is above 0.1mm, mainly used for JIg making and software reinforcing material, electrical insulation gasket.
  4. FR4 features: low water absorption, good durability, and good bending strength.