What are the common PCB materials, their pros, and cons?

What are the common PCB materials, their pros, and cons?

What are the common PCB materials, their pros, and cons?

Introduction

The most important part of electronics is the Printed Circuit Board. Because of the importance of these boards in any electronic device from home appliances to advanced communications devices, the selection of PCB materials should be done with proper knowledge of the electrical necessities of the considered equipment. In manufacturing a PCB, the choice of the main material is extremely important and is highly dependant on the electrical, thermal and mechanical parameters of the used matter. Some of these parameters include heat tolerance, adhesion, tensile strength, flexibility, dielectric strength, dielectric, etc. It is important to assess the material’s efficiency for each particular design. The PCB’s quality and compatibility rate depend entirely on the product used to produce the PCB. Circuits can be transferred between a host of various components with PCB materials. The metal that allows current flow between the board and any connected components is known as solder, which with its adhesive properties often serves a dual purpose.

PCB Materials

1. FR-4

FR4 or (Flame Retardant level 4) is a glass fiber/epoxy composite and is the most popular glass laminated material for all types of PCB production. FR4 is the most effective composite material because it has very good mechanical strength, based on glass-epoxy woven compounds. This is the material most commonly used in PCBs. It is a sheet of epoxy laminate reinforced with glass. The epoxy used is resistant to fire and heat. It gives good weight ratios strength. The tensile strength this material provides is very strong.

Single-Sided PCBs with Exposed FR4 Substrate

Single-Sided PCBs with Exposed FR4 Substrate

Pros:

  • Most frequent and widely used.
  •  
  • With a higher temp of the glass transition.
  • Compatible with the lead-free reflow technology
  • Halogen-free
  • Good insulation properties
  • Good arc resistance
  • Low water absorption
  • High familiarity among manufacturers

Cons:

  • Er (dielectric constant) stability from lot to lot and over frequency is one of them.
  • The loss is another, then lead-free processing temperatures are concerned, and perhaps thermal conductivity as even low-power RF can consume a lot of power if the active circuits are biased to provide very high linearity.

2. PTFE (Teflon)

PTFE is a type of plastic material that does not provide any resistance and is therefore used for applications of high speed and high frequency. PTFE is extremely flexible, making it useful in close resistance applications. It is also extremely lightweight, so it can be used across different industries. It is also flame-resistant, has high physical strength, provides stability in temperature, and is versatile in application.

Teflon/PTFE microwave materials/pcbs

Pros:

  • PTFE materials are rated in high-frequency applications for their suitability.
  • PTFE materials feature dielectric constant values as low as 3.5 or less, making them ideal to address FR-4’s high-speed limitations.
  • These materials also give very impressive thermal characteristics for high-temperature PCB applications, reaching Tg values up to 280 ° C.C.

Cons:

  • Like FR-4, PTFE content is not included in the PCB Options at a standard price of this material is substantially higher than standard FR-4.
  • PTFE materials also require additional treatment during PCB manufacturing due to a few particular aspects of the material itself compared to standard FR-4.
  • PTFE materials are rather soft making them susceptible to gouging or tearing during the process of PCB routing and PCB drilling.
  • The other main concern during production is the most well-known aspect of PTFE: due to the slick, non-stick surface it provides, this material is used to coat frying pans and cookpots.

3. Metal

PCBs still use traditional materials such as copper, aluminum, iron, etc. Such materials allow the integration of components using Surface Mount Technology (SMT). They offer mechanical resilience as well. Therefore, the steel base PCBs’ material life is much longer. A Metal Core Board or Insulated Metal Substrate (IMS) material gives better heat dissipation than most other materials to enable the effective cooling of surface-mounted components. It also brings a lower cost and density than other metal materials, so when significant cooling is required in PCBs such as LEDs or power switches, it is the metal of choice.

Pros:

  • Superior heat dissipation
  • Resilient and durable
  • Lightweight metal choice
  • A more environmentally friendly PCB material
  • A low-cost and always available
  • Its processing cost is also low.
  • The final products are low priced.
  • They are more stable and efficient from a technical point of view, maximizing brand longevity and reliability.
  • They are exceptional in terms of EMC-EMI shielding properties from an electrical point of view.

Cons:

  • The existing standard can only do single aluminum PCBs, double-sided aluminum PCBs are impossible to do.
  • In electrical strength and pressure, the product will be easier to have mattered.
  • Aluminum is vulnerable to quicker attacks by halide ions, the most commonly encountered of which is chloride

4. Rogers PCB Material

While FR4 is the most commonly used PCB material when it comes to high-frequency applications, Rogers PCB material is used. The name comes from Rogers Company that produces this material. In Rogers material, no glass fiber is used in the middle of, it is rather ceramic-based high-frequency material. It carries RT/duroid 5880, which is often used in communication applications and devices. Some of the pros given by its company include the followings:

Rogers PCB Material

Rogers PCB Material

Pros:

  • Lower Dielectric loss
  • Low electrical signal loss
  • Wide range of dielectric constant (DK) with values (2.55-10.2)
  • Low-cost circuit fabrication
  • Low outgassing for space applications

Conclusion

The different materials used in the design and manufacture of PCBs all offer a range of advantages and disadvantages. The product is selected based on the specification, the appropriate performance, environmental factors and any other restrictions encountered by the PCB. Depending on the expected results, you should select the PCB material. Your choice of PCB content will depend on the PCB’s prototyping criteria and intent.

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