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What is FR3 PCB ?

The FR3 PCB is a circuit board design program that’s affordable, intuitive, and versatile enough for beginners and professional designers. The main benefits of this program include its high level of compatibility. It also consists of the low cost of the software licenses, an extensive library, and full editing capabilities in vector format. The FR3 also allows users to create custom libraries that we can share using this software. It is perfect for those who want to take their PC board layout skills to the next level.

Although these programs are very similar, they have significant differences that set them apart. The FR3 software is more comprehensive and user-friendly than the Eagle software, but it comes at a much higher cost. It also allows unlimited polygons and tracks with a low polygon count of 5,000 and a track count of 10,000 per board. While the Eagle software has a lower polygon count at 4,900 and a lower track count at 8,000 per board. However, their differences do not end there. The most apparent difference between the programs is each product’s license costs.

How does FR3 compare to FR4?

FR4 is the FR3 PCB’s later successor. The significant difference between the two programs is that FR4 comes with more and better features than FR3. It has an enhanced interface and better usability, with a less complex learning curve. In addition, the program allows easier routing capabilities when users want to achieve their final design. It also contains a helpful and extensive library with symbols, footprints, and templates that users can use in their designs.

The FR4 software has many advantages over the FR3 PCB, but it also has shortcomings. The main disadvantage of the FR4 is that it only supports four layers and a total design size of 8.27 inches by 11 inches. Another drawback is that there are no designated libraries for FR4. Although, beneficial symbols and footprints are in this website’s library section. Lastly, the program only allows a maximum polygon count of 3,000 polygons and a maximum track count of 6,000 tracks per board.

The best advice anyone can give regarding these programs is to try using both. Do this before deciding what you would like to use professionally or recreationally in your projects.

Materials used in FR3 PCB

Standard FR3 PCB materials include:

1. Glass-reinforced phenolic (FR-4) substrate with pre-molded copper cladding. This provides ease of manufacture, mechanical stability and durability, excellent track density capability, and low cost.

2. Copper capped alumina substrate (FPAK) is an alternative to GF material. We use them for high-temperature applications or where arcing is a problem. FPAK provides excellent thermal conduction. In addition, it allows for increased current carrying capacity compared to standard FR4 material.

3. We can use single-sided glass laminate (SGLA) with low power boards. This requires extra strength and protection from moisture or corrosive atmosphere. Examples include automotive or industrial applications.

4. Non-conductive epoxy resin (NCER) is helpful for areas where we cannot use conductive traces. Examples include connectors and through-hole vias.

5. We use Pressure-sensitive adhesive (PSA) for attaching parts, for example, ICs, to the PCB.

6. Electroless nickel immersion gold and chemical/mechanical polishing achieve surface finish within or beyond 25 µin.

7. Pre-punched paper tape helps hold down components during the assembly of the PCB. We can dispense it from press-fit machines directly onto the PCB surface. We do not need any additional adhesive.

Number of layers

FR3 PCBs are one layer (1-layer) to eight layers (8-layer).

We can manufacture the FR3 PCB in single or double-sided versions.

The FR3 PCB is a one-sided technique. It uses a copper-clad substrate with two or more layers of copper foil laminated onto each side of the substrate.

We etch the traces on the substrate, and then we remove the copper from all but the required layers. Next, we create ground planes by etching away all exposed copper between the required traces leaving isolated ground areas where needed. Through-hole plated holes allow for mounting components and surface-mounted devices.

CAD Design

The CAD package used to produce the FR3 PCB is Eagle PCB Editor. The PCB copper foil or copper cladding consists of 35μm and 163μm thickness material. The FR3 PCB has a maximum line width of 2.5 µm and minimum line width of 0.15 µm (15 mils).

The FR3 PCB can have up to three levels of hierarchy in its design: board, layer, and track level. This allows the minimum number of total tracks on the board to be 8 for multilayer pcb boards with no vias. Ground planes are essential for all signal layers except for signal layer number six. It may not contain any ground plane.

Best ways to drill holes in FR3

We can achieve drilling the FR3 PCB in several ways. First, through-hole drilling using hand tools is usually suitable for PCBs with through-hole vias.

PCB thickness can vary from 0.8mm for single-layer boards to 1mm for double-layer boards.

Through-hole vias must be straight and vertical to provide maximum trace clearance. Unfortunately, this gives rise to two problems when drilling holes in FR3 PCBs with through-hole vias.

  • Drill bit contact
  • Increased resistance to vibration

a) Mechanical drilling:

We must use a drill bit with a larger diameter to prevent the bit from binding in the smaller hole. This will increase resistance to vibrations. Drill motors are available specifically for drilling through holes in FR3 PCBs. They do not require an additional threaded insert. However, these can cost up to $200 each.

b) Laser drilling:

A laser cutter is a great way to make straight-through holes in FR3 PCBs. The cutters can create 0.5mm holes within a 0.25mm hole, resulting in minimal clearance from the drill bit to the FR3 PCB surface. This increases drilling resistance and vibration. We can minimize it by using an oscillating hand drill on FR3 PCBs with through-hole vias or ground planes.

c) Drill bits:

We can order drill bits for 14 and 16 gauge HSS drills from McMaster-Carr or Mouser Electronics for $100 each. Cheaper options are available if several holes need drilling to accommodate through-hole vias.

Applications for FR3 PCB

The FR3 PCB is essential in various applications in the electronics industry. However, it is also applicable to many applications that require high strength, ease of assembly, and small size.

Electronics:

The FR3 PCB is helpful as the board material in motherboards, consumer-level computers, and mobile devices.

Automotive:

The FR3 PCB can be helpful in automotive applications because of its low cost, durability, and reliability. In addition, it is helpful to any auto parts manufacturer that needs to manufacture small batches with minimal lead time.

Automotive applications of the FR3 PCB include:

a) Instrument clusters display vehicle information such as speed, RPM, and other valuable metrics. Applications include the dashboard, center counsel, and in-vehicle entertainment (IVI) systems.

b) Power supply modules, which we can integrate with other modules or build into compatible devices. Examples include airbags and ABS sensors, and we use them for automotive purposes. This allows you to install circuit boards with specific functions in any number of locations inside the vehicle. You do not need to change any wiring or software changes.

Industrial:

The FR3 PCB is helpful in high-performance, highly reliable industrial applications. Examples include computer-controlled instruments and sensing devices.

Electronic or electromechanical sensors are usually installed on the boards and connected to external equipment through wires. These are inside various housings, such as extruded aluminum housing, to ensure the board has no contact with air.

The FR3 PCB can also be essential for in-vehicle electronics. It makes it easy for Rayming PCB & Assembly to create new electrical and electronic systems quickly.

Others:

RFID tags are commonly mounted onto FR2 PCBs. We then transfer it onto their final application using an adhesive that adheres to the FR3 PCB tag. These are generally 0.5 to 2mm thick.

Conclusion

FR3 PCBs are inexpensive, more rigid, and stronger than FR1 PCBs. As a result, they provide a low-cost and reliable board alternative to aluminum PCBs. In addition, FR3 PCBs are lighter, take up less space, and we can manufacture them faster than FR4 PCBs.

The FR3 PCB has a wide variety of applications in the electronics industry, ranging from video games to mobile devices.

FR3 is not helpful for every application because of its rigidness and low thermal conductivity properties. However, it is a board with many unique properties that professionals can utilize.