When troubleshooting non-functional or poor performance circuits, engineers can run simulations or other analysis tools to consider the circuit from the schematic level. If these methods can not solve the problem, even the best engineers may be stumped and frustrated or confused. To avoid a similar dead end, I'll introduce
Prepreg, also known as pre impregnated material or bond sheet, it’s the main laminating material used in multilayer printed boards manufacturer. It is a type of thin sheet material made up of resins and reinforced. Reinforcement materials can be divided into glass cloth and other composite materials. Resins include epoxy
Printed circuit boards are a key element of various businesses, especially in the digital age when electronic technology is so important in many different areas. Different types of printed circuit boards also come in different types, depending on the needs of a particular company or industry, may have different materials,
When designing a PCB to factory fabrication, how to choose PCB material?
PCB material classification:
1. According to different materials (the most commonly used classification method)
Paper substrate (FR-1, FR-2, FR-3)
Epoxy glass cloth substrate (FR-4, FR-5)
Composite Substrates (CEM-1, CEM-3)
HDI sheet (RCC)
Special substrates (metal substrates, ceramic substrates, thermoplastic substrates, etc.)
2. Divided by resin
Phenolphthalein resin
PCB vias are the electrical connections between layers. Vias are handled in the following ways:
PCB vias be covered:
Standard: Over-line holes must be covered, normal screen-printed solder resisted, no special plug-hole treatment;
Plug, part of the hole is not plugged, must accept the mouth of the yellow, but does not receive the
COB wire bonding is a wire bonding method in the chip production process. It is generally used to connect the internal circuit of the chip and a package pin or a gold-plated copper foil of the circuit board before packaging with a gold wire or aluminum wire.COB wire bonding is
Flexible circuits are used in various applications where conductors are connected to each other,these conductor interconnections must be bendable or be able to remain bent for long periods of use. In the past, this interconnect technology was implemented using wire interconnections.
There are many kinds of flexible circuits:
One is a two-way
With the continuous development of science and technology, PCB laser drilling is more and more widely used.Here, let the flexible circuit board manufacturers introduce the following 2 intuitive phenomena: what is PCB laser drilling and the matters needing attention.
1. How does laser produce?
Laser is a gas mixture gas in a closed circular space (see below
1.The present situation
Printed circuit boards cannot be reassembled after assembly, the cost loss is very high caused by microvoid.The problem is due to PCB design defect lead to weldability,it has been verified by the original equipment manufacturer (OEM).It has nothing to do with immersion silver or other final surface treatments.
2.Root cause analysis
By analyzing the root cause of defects,
The early process of Rigid-flex PCB board is use connector or hotbar process to connect two PCBs with flex board.This combination with the flex board and rigid PCB process is time-consuming and laborious, so customers transfer the assembly to PCB manufacturer to make rigid-flex PCB.
In addition to the price, the use of Rigid-flex Board has many advantages, listed as follows:
1.It can effectively save the space on the circuit board and save the use of the connector or the HotBar process, Because of flex PCB and rigid PCB get together, so that require the use of connectors or HotBar process space can be saved, saved space is very important for some high density board,it also saved the cost of using the parts of the connector or the cost
2. of the HotBar process. In addition, the space between the two pieces of the board can also become more compact because it saves the connector.
3.The distance of the signal transmission is shortened and the speed is increased, and the reliability can be improved effectively.
The traditional transmission of the signal through the connector is circuit board --->connector--->flex board--->connector--->circuit board. The signal transmission of rigid-flex PCB is reduced to the circuit board--->flex PCB---> circuit board.The distance between signal transmission is shorter, and the problem of signal transmission attenuation between different media is also reduced.The wiring on the general circuit board is copper material, and the contact terminal of the connector is gold-plated. The solder joints are plated with tin, and solder paste is applied to the printed circuit board. The transmission of signals between different metal will be attenuated.If we change to rigid-flex boards, these media will become less, and the ability of signal transmission can also be improved.
4. Simplifying the assembly of products and saving the time of assembly
The use of rigid-flex PCB can reduce the time of SMT process, because the number of connectors is less.It also reduces the time for the assembly of the whole machine, because it saves the assembly of the flex board into the connector, or saves the process of the HotBar. It also reduces the cost of part management and inventory, because the BOM table is reduced, so management becomes less.
The disadvantage of rigid-flex PCB:
After comparison,the biggest weakness is that rigid-flex PCB boards is more expensive.The cost is nearly doubled than flex PCB +rigid PCB.But if the price of the connector is deducted or the cost of HotBar, the price is likely to be same. Another disadvantage is that both SMT and carrier may need to use a tray (carrier) to support the part of the flex board, which virtually increases the assembly cost of the SMT.
