2 Vật liệu bo mạch pcb 4 lớp phổ biến nhất (Hướng dẫn 2020)2020-09-28
Vật liệu nhiều lớp pcb 4 lớp là gì?
PCB là gì?
Bảng mạch in là một tấm điện môi, trên bề mặt và / hoặc trong thể tích có các mạch dẫn điện của mạch điện tử được hình thành. Bảng mạch in được thiết kế để kết nối điện và cơ của các thành phần điện tử khác nhau.
Bo mạch pcb 4 lớp là gì?
4 layers pcb board is a printed circuit board that has a copper foil pattern on both sides. And a two-layer copper foil pattern inside the board.
The two layers inside the board are often assigned to GND and power supply, respectively.
I wonder why printed circuit boards manufactured through various processing processes are “raw” boards. .. ..
What is difference between single layer and double layer pcb?
Generally, this is because it is expressed by the number of copper layers.
A single-sided plate is single-sided because it has a copper layer on only one of the front and back sides.
The double-sided plate has copper layers on both the front and back (two sides), so it has both sides (two layers).
After making a 4 layers pcb board plate or a 6-layer plate, if you peel off (eliminate) the copper on either the front or back layer,
Moreover, 3-layer and 5-layer plates can be made. It is due to the nature of the material used (glass epoxy resin),
Importance of copper in 4 layers pcb board
Without copper, it loses the force of contraction, causing the printed circuit board to warp or bend.
It induces problems such as:
- adverse effects on component mounting
- and inability to incorporate it into the housing
Similarly, the same stress is generated in the inner layer. Hence, it must be sandwiched between copper like a sandwich.
Therefore, even if it is a concept that copper is not needed because either the front or back layer is not used as a signal line or power supply layer.
Furthermore, a copper layer is required in 4 layers pcb board, resulting in an even number of layers.
How to connect electronic components?
Electronic components on a printed circuit board are connected by their pins to elements of a conductive pattern, usually by soldering.
In contrast to surface-mounted mounting, the electrically conductive pattern on the printed circuit board is made of foil. Subsequently,iIt is entirely located on a solid insulating base. The printed circuit board contains mounting holes and pads for mounting lead-out or planar components.
In addition, printed circuit boards have vias for electrically connecting foil sections located on different layers of the board. On the outside, the board is usually covered with a protective coating (“solder mask”) and markings.
Depending on the number of 4 layers pcb board layers with an electrically conductive pattern, printed circuit boards are divided into:
- One-sided (OPP): there is only one layer of foil glued to one side of the dielectric sheet.
- Double-sided (DPP): two layers of foil.
What material will we use to make 4 layers pcb board?
The most common materials available for the manufacture of boards are:
- Getinax and
Getinax paper impregnated with bakelite varnish, fiberglass textolite with epoxy. Therefore, we definitely use fiberglass!
What is fiberglass laminate sheet?
Foil glass fiber laminate is a sheet made on the basis of glass cloth. In addition, it is impregnated with a binder based on epoxy resins. It is lined on both sides with electrolytic copper electroplated foils 35 microns thick.
The maximum permissible temperature is from -60 ° C to + 105 ° C. It has very high mechanical and electrical insulating properties. Hence, it lends itself well to mechanical processing by cutting, drilling, stamping.
4 layers pcb board designing choice
The choice of PCB design is an important factor in determining the mechanical performance of the device as a whole. Moreover, materials of various quality levels are used for the manufacture of 4 layers pcb board.
It will be most suitable and convenient for the developer if the PCB manufacturer is nearby. In this case, it is easy to control the resistivity and dielectric constant – the main parameters of the PCB material.
Unfortunately, this is not enough and knowledge of other parameters is often necessary, such as:
- high temperature stability
These parameters can only be known by the manufacturer of the components used in the production of printed circuit boards.
Vật liệu nhiều lớp pcb 4 lớp là gì?
Laminated materials are designated FR (flame resistant) and G. Material with the FR-1 index has the highest flammability, and FR-5 – the least. Materials with indexes G10 and G11 have special characteristics.
Do not use PCB category FR-1 for 4 layers pcb board. There are many examples of the use of FR-1 PCBs that are damaged by the thermal effects of powerful components. PCBs in this category are more like cardboard.
Difference between fr4 and fr2
FR-4 is often used in the manufacture of industrial equipment. Similarly, FR-2 is used in the manufacture of household appliances. These two categories are standardized in the industry. Moreover, FR-2 and FR-4 PCBs are often suitable for most applications.
But sometimes the imperfection of the characteristics of these categories forces the use of other materials. For example, for very high frequency applications, fluoroplastic and even ceramics are used as PCB material. However, the more exotic the PCB material, the higher the price can be.
How to choose 4 layers pcb board material?
When choosing a 4 layers pcb board material, pay special attention to its hygroscopicity. As this parameter can have a strong negative effect on the desired characteristics of the board:
- surface resistance
- High voltage insulating properties (breakdowns and arcing) and mechanical strength.
Also pay attention to the operating temperature. Hot spots can occur in unexpected locations, such as near large digital integrated circuits that switch at high frequencies.
If these areas are located directly below analog components, the rise in temperature can affect the performance of the analog circuit.
Printed circuit boards are represented by an even number, except for single-sided boards, flexible (FPC) boards, and special boards (aluminum, etc.), such as:
- double-sided boards
- 4 layers pcb board, and
- 6-layer boards.