Do you Know how to Choose the Suitable PCB Materials?

There are many factors to consider before starting to choose a PCB. One of them is to ensure that the material properties meet your specific board requirements and end applications. So this article will introduce you how to choose a suitable PCB material.

What should you consider when choosing PCB materials?

PCB board purchase principles

• For general electronic products, FR4 epoxy glass fiber substrate is used.

• For the use of high ambient temperature or flexible circuit boards, polyimide glass fiber substrates are used.

• For high-frequency circuits, you need to use a PTFE glass fiber substrate.

• For electronic products with high heat dissipation requirements, metal substrates should be used.

Factors to consider when choosing PCB materials

• A substrate with a higher glass transition temperature (Tg) should be appropriately selected, and the Tg should be higher than the operating temperature of the circuit.

• The coefficient of thermal expansion (CTE) is required to be low. Due to the inconsistency of the thermal expansion coefficients in the X, Y and thickness directions. It is easy to cause deformation of the PCB, and in severe cases, it will cause the metallized hole to break and damage the components.

• High heat resistance is required. Generally, PCB circuit boards are required to have a heat resistance of 250C / 50S.

• Good flatness is required. SMT PCB warpage requirements are <0.0075mm/'mm.

• In terms of electrical performance, high-frequency circuits require materials with high dielectric constant and low dielectric loss. Insulation resistance, voltage strength, and arc resistance must meet product requirements.

When choosing a sheet, we need to consider the impact of SMT

In the process of lead-free electronic assembly, as the temperature rises, the degree of bending of the printed circuit board when heated is increased. Therefore, it is required to use a board with a small degree of bending in SMT, such as FR-4 type substrate. FR-4 refers to a grade of material rather than a material, which is a composite material for glass-reinforced epoxy laminate material. FR-4 is made up of woven fiberglass cloth with an epoxy resin binder that is flame resistant. And FR stands for flame retardant, it denotes that the material complies with the standard UL94V-0. Since the expansion and contraction stress of the substrate after heating affects the components, it will cause the electrode to peel off and reduce the reliability. Therefore, the material expansion coefficient should be paid attention to when selecting the material, especially when the component is larger than 3.2×1.6mm. The PCB used in surface assembly technology requires high thermal conductivity, excellent heat resistance (150℃, 60min) and solderability (260℃, 10s), high copper foil adhesion strength (1.5×104Pa or more) and bending strength (25 ×104Pa), high conductivity and small dielectric constant, good punchability (accuracy ±0.02mm) and compatibility with cleaning agents, in addition, the appearance is required to be smooth and flat, without warpage, cracks, scars, and rust spots.

In general, this article introduces some issues that need to be considered when choosing PCB materials. If you want to buy a PCB, Ouke will be a good choice. For more information about PCB, you can consider consulting Ouke. This is a supplier of industrial automation solutions, providing one-stop service automation systems for the industry like Fanuc PCB circuit boards, Fanuc CPU board circuit, Fanuc cnc system card PCB circuit board, Fanuc servo drive, Fanuc servo motor encoder, Fanuc circuit boards, Fanuc teach pendants, Fanuc inverter circuit board, Fanuc controller systems, etc.