Tips to know about Semi-Flexible FR4 Printed Circuit Boards
FR4 is a flame-retardant material
Printed circuit boards made from FR4 are extremely durable. However, the cost of these boards is higher than the ones made from other materials. In addition, these boards tend to delaminate easily, and they emit a bad odor when soldered. This makes them unsuitable for high-end consumer electronics.
FR4 is a composite material that has excellent mechanical, electrical, and flame retardant properties. It is a yellow to light green material that withstands high temperatures. It is made of a fiberglass layer that gives the material its structural stability. The material also features an epoxy resin layer that provides it with its fire retardant properties.
FR4 PCBs can be produced with a varying thickness. The thickness of the material affects the weight of the board and its component compatibility. A thin FR4 material can help make a board lighter, which makes it more appealing to consumers. This material is also easy to ship and has excellent temperature resistance. However, it is not advisable for use in high-temperature environments, such as aerospace.
It has excellent thermal, mechanical, and electrical properties
FR-4 is a common printed circuit board substrate made from glass cloth impregnated with epoxy or hybrid resin. It is widely used in computers and servers and is well known for its excellent thermal, mechanical, and electrical properties. It can withstand high temperatures, which makes it an ideal choice for sensitive electronics.
However, FR4 semi-flex PCBs present some challenges when it comes to depth-controlling milling. In order to achieve good results with this type of material, the board’s remaining thickness must be uniform. The amount of resin and prepreg used must also be considered. The milling tolerance should be set appropriately.
Besides the excellent thermal, mechanical, and electrical properties, FR4 is lightweight and inexpensive. Its thinness is a major advantage over FR1 printed circuit boards. However, it should be noted that this material has a lower glass transition temperature than FR1 or XPC. FR4 PCBs are made from eight layers of glass fiber material. These boards can withstand temperatures between 120 degrees C and 130 degrees C.
It has a high signal loss compared to a high-frequency laminate
While the low cost and relative mechanical and electrical stability of FR4 makes it an attractive choice for many electronic applications, it is not appropriate for all applications. In cases where high-frequency signals are required, a high-frequency laminate is the better choice.
The dielectric constant of the laminate material plays a critical role in determining the best PCB. The higher the dielectric constant, the less signal loss the board will experience. This dielectric constant is a measure of the board’s ability to store electrical energy.
When comparing the signal loss of a printed circuit board with a high-frequency laminate, you can see that the former has a higher dielectric constant. In other words, the Semi-Flex FR4 material has a higher dielectric constant than the latter. A high dielectric constant is desirable for high-speed applications because it prevents signal loss.
FR-4 was not the first PCB material to be used for electronics. It was preceded by the FR-2 board, which was made from pressed phenolic-cotton paper. This material served as a bridge between discrete-wired hand-soldered circuits and FR-4. Some Magnavox advertisements advertised that the televisions were “hand-soldered”. FR-2 boards were often one-sided, but designers could solve the problem by using top-side jumpers and zero-ohm resistors.
It can be manufactured at a low cost
Semi-flex PCBs are flexible, and are ideal for applications where space is a consideration. While these PCBs are more expensive than conventional FR4 boards, the flexibility that they provide makes them ideal for many medical applications. Also, the flexibility that they provide is better suited to handling dynamic stress resulting from bent circuit boards.
Semi-flex PCBs are made with materials that are typically manufactured in rolls. These materials are then cut according to the final size of the product. For example, a roll of copper foil is cut to the desired shape, which then requires mechanical drilling to make the through-holes. Different hole diameters are used, which vary according to the needs of the customer.
However, the bending properties of this material can cause problems. For instance, FR4 is not suitable for bending at very high temperatures, as it tends to warp. To prevent such problems, it is necessary to ensure that the materials are made of a flexible material before they are etched or molded.