Types of PCB
A Printed Circuit Board (PCB) electrically connects and mechanically supports various electronic components. We do this by using conductive pads or tracks. These are etched from copper laminated sheets. However, we also include a non-conductive substrate. There are various types of PCB boards and they have specific applications. Today we will take a look at some of them.
A single-sided PCB is one of the types of PCB and is made from a single layer of a substrate. Only one side of this substrate is coated with copper. In single-layer boards, we solder various components onto one side. So, this makes it easier to design and produce a single-sided PCB. Therefore, they have a low cost and we can manufacture them in high volumes. Hence, we commonly use single-layer PCB in simple applications like calculators, printers, radio, and cameras.
Double-sided PCB is also among the types of PCBs. They have a substrate material like single-layer PCB. However, the substrate is coated with copper on both sides. We can drill holes in double-layer boards to allow the connection between components on opposite sides.
We use these types of PCB in applications that have intermediate complexity. Therefore, the typical examples include LEDs, amplifiers, HVAC systems, vending machines, and car dashboards.
Multi-layer PCB has multiple layers of PCB. So, we have to use a specialized glue for securing them together. We need to place the layer of boards by sandwiching them between insulation layers. Therefore, we can ensure that excess heat won’t damage the components.
These types of PCBs are suitable for a wide range of advanced electronic applications. So, we often use multi-layer PCB in data storage, file servers, satellite systems, medical equipment, GPS technology, and weather analysis.
We manufacture rigid PCB from a solid substrate which prevents the twisting of the board. A computer motherboard is a common example of a rigid PCB. The motherboard is designed for allocating electricity from the power supply and facilitating communication between various computer parts such as GPU, RAM, and CPU. Rigid PCBs are the most abundant type of PCB. So, we use rigid PCB in those applications where we want to prevent the deformation of PCB and increase its lifespan.
Flexible PCB is the exact opposite of rigid PCB. As the name suggests, these PCBs are very flexible and can move freely. Since flexible PCB needs flexible manufacturing material, therefore, they have a high manufacturing cost.
Flexible PCB offers many benefits that rigid PCBs are unable to offer. We can fold flexible PCB over their edges and wrap them around the corners. Their flexibility allows them to have lightweight and hence we can use them in small spaces.
We can also use flexible PCB in those areas which are subjected to environmental hazards. However, to achieve this, we have to manufacture them by using waterproof, corrosion-resistant, and shockproof materials. This is something that the rigid PCB is not capable of.
Flex rigid PCB
These types of PCB combines the best of both worlds as they depict the properties of both the rigid and flexible PCB. These boards have multiple layers of rigid PCB attached to a number of flexible PCB layers.
These boards have more benefits than those offered by flexible or rigid PCB alone. Flex-rigid PCB has a lower parts count than the conventional flexible or rigid boards. This is because we can combine the wiring options for both of them into a single PCB. When we combine the properties of flexible and rigid PCBs in the flex-rigid board then we get a reduced size, streamlined design, and lighter weight.
We mostly use flex-rigid PCB in those applications where weight and space are of prime concern. This includes digital cameras, automobiles, cell phones, and pacemakers.
Materials for PCB Manufacturing
The dielectric substrate is a major part of PCB which is either flexible or rigid. We use a dielectric substrate with a copper coating. We will now discuss some of the materials which we frequently use for manufacturing PCB.
FR is an abbreviation for Fire Retardant. FR4 is the most common glass laminated material for all types of PCB fabrication. FR4 is a composite material that is based on woven glass-epoxy compounds. It is very useful because it gives us excellent mechanical strength.
FR-1 and FR-2
This material is based on phenol and paper compounds. We mostly use this material only for single-layer PCBs. Both FR2 and FR1 have the same properties. However, they have one difference which is glass transition temperature. FR2 has a lower glass transition temperature in comparison to the FR1. We further divide these materials in halogen-free, standard, and non-hydrophobic.
This material is a composite of phenol compounds, paper, and woven glass epoxy. We use this material only for single-layer PCB. We can use CEM-1 as an alternative to FR4. However, CEM-1 is more costly than FR4.
This material is white in appearance and we mostly use it in double-layer PCBs. It is based on glass epoxy compounds. CEM-3 is cheaper than FR4 so it is a good alternative. However, it has lower mechanical strength in comparison to FR4.
We mostly use this material in flexible PCBs. It is based on rogers, kepton, and dupont. It has good felicity, electrical properties, high chemical resistance, and wide temperature range. The operating temperature of this material is from -200 ͦC to 300 ͦC.
It is a kind of fiberglass that is impregnated with resin. These resins are pre-dried, so it sticks, flows and completely immerses when heated. The adhesive layer of the prepreg gives it a comparable strength to the FR4.
There are many forms of this material which have varying resin content. These include Medium Resin (MR), Standard Resin (SR), and High Resin (HR). We choose between these according to the layer structure, required thickness, and impedance.
MOKO Technology is a leading company in the field of Printed Circuit Boards (PCBs). We specialize in all types of PCB manufacturing with multiple materials since 2006. Feel free to contact us if you have any queries or if you want a quote.