Professional 32-layer PCB Rapid Proofing In the circuit board, if there is a signal transmission, it is hoped that it can be smoothly transmitted from the sending end of the power supply to the receiving end with the minimum energy loss, and the receiving end will completely absorb it without any reflection. To achieve this transmission, the impedance in the line must be equal to the impedance inside the transmitter, which is called “impedance matching”. When designing high-speed PCB circuits, impedance matching is one of the design elements. The impedance value has an absolute relationship with the routing mode. For example, whether you walk on the Microstrip or the inner strip/double strip, the distance from the reference power layer or ground layer, the width of the trace, the PCB material, etc. will affect the characteristic impedance value of the trace. That is to say, the impedance value can only be determined after wiring, and the characteristic impedance produced by different PCB manufacturers is slightly different. General simulation software can’t take into account some wiring situations with discontinuous impedance due to the limitation of circuit model or mathematical algorithm used. At this time, only some Temninators, such as series resistance, can be reserved on the schematic diagram to alleviate the effect of impedance discontinuity. The fundamental solution to the problem is to try to avoid impedance discontinuity when wiring.
Process flow and technology of multilayer board
Manufacturing the core-laminating RCC-laser drilling-hole plating-pattern transfer-etching and film stripping-laminating RCC-repeatedly forming an integrated printed circuit board (HDI/BUM board) with an a n b structure.
(Note 1): The core board here refers to all kinds of boards, such as conventional double-sided and multilayer boards, buried/blind-hole multilayer boards, etc. However, these core plates must be plugged and ground flat before they can be laminated.
(Note 2): The HDI/BUM multilayer board structure can be represented by the following formula.
A- is the number of layers laminated on one side, n- is the core board, and b- is the number of layers laminated on the other side.
The guarantee of performance depends on PCB design, and everyone knows this point. The same logical connection, the same device, and different PCBs have different performance test results. Good design not only has high product stability, but also can pass various demanding tests. However, it is impossible to achieve such an effect if the design is not ideal. In some low-end products, many manufacturers use the same chipset, and the logical connections are similar. The only difference is the level of PCB design, and the difference of products is mainly reflected in the design of PCB. Fast proofing of 32-layer circuit board
The ease of processing is also an important index of PCB design. Good PCB design is convenient for processing, maintenance, testing and manufacturing. The quality of PCB is not only related to the production efficiency of PCB manufacturers and SMT manufacturers, but also closely related to our convenience of testing and debugging.
PCB board soft and hard difference
It is divided into rigid circuit board, flexible printed circuit board and soft-hard board.
The intuitive difference between rigid PCB and flexible PCB is that flexible PCB can be bent. Common thicknesses of rigid PCB are 0.2mm, 0.4mm, 0.6mm, 0.8mm, 1.0mm, 1.2mm, 1.6mm, 2.0mm, etc. The common thickness of flexible PCB is 0.2mm, where the parts are to be welded, a thickened layer will be added on its back, and the thickness of the thickened layer varies from 0.2mm to 0.4mm. The purpose of understanding this is to provide structural engineers with a spatial reference when designing. Rigid PCB materials commonly include: phenolic paper laminate, epoxy paper laminate, polyester glass felt laminate, epoxy glass cloth laminate; The materials of flexible PCB commonly include: polyester film, polyimide film and fluorinated ethylene propylene film.
Process requirements for rapid proofing of 32-layer circuit board and PCB welding
2.1 technological requirements for processing components
2.1.1 Before inserting the components, the solderability of the components must be treated. If the solderability is poor, the pins of the components should be tinned first.
2.1.2 After shaping the pins of components, the pin spacing requirements shall be consistent with the corresponding pad hole spacing of PCB board.
2.1.3 The shape of component pin processing shall be conducive to the heat dissipation of components during welding and the mechanical strength after welding.
2.2 process requirements of components inserted in PCB board
2.2.1 The order of inserting components in PCB is low before high, small before big, light before heavy, easy before difficult, general components before special components, and the installation of the previous procedure cannot affect the installation of the next procedure.
2.2.2 After the components are inserted, their signs should be easy to read and read from left to right as much as possible.
2.2.3 The polarity of components with polarity shall be installed strictly according to the requirements on the drawings, and the components with polarity shall not be installed by mistake.
2.2.4 The insertion of components on PCB should be evenly distributed, neatly arranged and beautiful. Oblique arrangement, three-dimensional crossing and overlapping arrangement are not allowed; It is not allowed to be high and low on one side; It is also not allowed for pins to be long on one side and short on the other.
2.3 process requirements of PCB solder joints
2.3.1 The mechanical strength of solder joints shall be sufficient.
2.3.2 reliable welding, to ensure the conductivity.
2.3.3 The surface of solder joints shall be smooth and clean.
The demand for 9HB single-sided cardboard proofing is not large, so there is no way to put together a large number of 94HB single panels for proofing, but to use a single sheet to feed and produce, so the cost is generally 200. Many people are also surprised that 94HB single panel belongs to paper substrate, which is a relatively cheap product in itself, while FR-4 fiberglass board belongs to mid-range products. Why is the proofing price still expensive? This is the reason.
