A PCB or printed circuit board generates heat when an electric current flows through it. Without proper insulation, this heat can cause serious problems for PCBS.

Why do PCBS need insulation?

Before you can understand PCB insulation, you must understand: What is PCB?

PCBS, or printed circuit boards, are small green squares with copper sheets (but also in other colors). It can be found in almost any electronic device! Printed circuit boards enable electronic devices to function properly, making them a vital but invisible part of everyday life. Without them, computers, telephones, televisions and electronics would not work or exist.

Electrical is very powerful for PCB. PCBS contain printed copper wires, so they naturally conduct electricity. However, electrical components can pose a hazard if they are not enclosed in a non-conductive housing or become too hot. The PCB must be insulated to prevent copper corrosion and reduce accidental contact with conductive materials. Proper insulation can help prevent the PCB from overheating or exploding.

There are several ways to isolate a PCB. There are several common insulation materials, but the exact type of insulation usually depends on the application of the PCB design.

Photo source: pixabay

PCB insulating material

Common PCB insulation materials are usually formed as non-conductive substrates that can be fused together in multiple layers to allow current to flow correctly through the entire circuit board. Simpler PCBS can be single-sided or single-layer. Complex PCBS, such as those used for high-speed digital communications, may contain more than two dozen layers.

PCB insulation calculator can help you determine creepage distance and electrical clearance, which will be the determining factor in the exact type and quantity of insulation material. Creepage distance is the shortest distance between conductive parts, and clearance is the element separated by air rather than the substrate. Understanding creepage distance and electrical clearance is essential for calculating PCB insulation.

PCB manufacturers can choose to use a variety of different materials for insulation, from inexpensive plastics like FR-2 to rugged metals such as aluminum. The insulating material of a PCB usually determines its use. For example, the PCB in a cheaply made electronic toy would not need the same type of insulation as the PCB in a satellite.

To better understand PCB insulation and insulation materials, let’s explore the five most common forms of PCB insulation.

FR-2

Fr-2 is a low grade flame retardant laminate option. It is made from a composite of paper and plasticized phenolic resin, making it light and durable. Single-sided circuit boards usually use this material. The FR-2 is halogen-free and hydrophobic and can be easily pressed or milled. The FR-2 is one of the cheapest options for PCB insulation and is a common choice for companies making disposable consumer electronics.

FR-4

Fr-4 is an advanced flame retardant laminate option. It is a composite material made of fiberglass woven fabric and is commonly used in the manufacture of double-sided and multi-layer PCBS. The FR-4 can withstand higher temperatures and physical pressures than the FR-2. It’s also an affordable material, making it a popular choice for manufacturers of high-end consumer electronics. The FR-4 is not machined fast, requiring milling, stamping or machined tungsten carbide tools.

Radio frequency (rf)

RF substrates are designed to allow PCBS to operate in applications using high power RF and microwave. RF substrates are most commonly used for PCBS installed in military electronics, avionics and avionics. It is important to note, however, that some consumer electronics products contain this type of substrate. The plastics that make up a typical RF substrate do not generate a lot of insulation and perform well for the task of generating large currents. RF and microwave PCBS usually have only one or two layers.

flexible

Although most printed circuit boards are flat and rigid, there are some innovative PCBS that can bend in almost any direction without breaking. Flexible circuits require a similar but unique form of insulation. Flexible circuits are usually protected with A SPRAY of PCB insulation, in addition to plastic film is a popular choice. Flexible circuits require thin, strong PCB insulation coating so that they can move freely and fit in tight Spaces.

metal

The choice of metal as an insulator may seem strange. Metals are normally electrically conductive, and accidental conduction can cause a PCB to fail, catch fire or melt. However, in some cases, a PCB with a metal substrate may be more advantageous. Metal is an excellent conductor of heat and can withstand huge currents without breaking or burning. PCBS installed in electrically charged equipment that consumes a lot of power may require metal substrates to function effectively.

Industry influence

To prevent the PCB from overheating, catching fire, or catching fire, it must be adequately insulated. The type of insulation corresponds to the type of use provided by the PCB.

General-purpose electronic PCBS are suitable for use with simpler and more cost-effective FR-2 or FR-4 substrates. RF substrates are more suitable for applications involving high power RF.

Flexible substrates such as plastics are well suited to meet the insulation requirements of flexible circuit boards. Metals, on the other hand, are excellent conductors of heat while keeping the power electrons cool.