For a basic PCB, the components are concentrated on one side and the wires on the other, so we call this PCB a single-side because it can only be wired on one side. Both sides of the double-side PCB can be wired, so the wiring area is twice as large as that of the single-side, making it suitable for more complex circuits.
For a simple circuit such as a radio, single-side or double-side PCB are enough. But with the development of microelectronics technology, greatly increased the complexity of the circuit, the electrical properties of the PCB is also put forward higher requirements, if still use single or double-side PCB, circuit volume will be very big, also brought great difficulty to cabling, in addition, the electromagnetic interference between the lines is not good, so there will appear a sandwich plate (layer on behalf of several independent wiring layer, is usually an even number). In general, many companies’ PCB boards are green, because the green process is mature and simple.
But in extreme cases, also can have red, white, blue, yellow, inferior smooth color, the more extreme cases have black, purple, chrysanthemum, such as colour, light green, under normal circumstances, the white one is making light must use white PCB of the product, other color is more product grading system, each company is different, PCB circuit board processing, the coating color is different also, some in red to represent the experimental board, some in blue to represent the key board, some with black to represent for panel inside the computer. Each has its own rules without a detailed table.
High quality circuit board production can do exactly right, and its years of accumulated production experience is closely related, circuit board production enterprises thus create a higher visibility and influence, accumulated a relatively fixed consumer groups.
The advantages of multi-layer board:
High assembly density, small volume; The connection between electronic components is shortened, and the signal transmission speed is improved; Convenient wiring; For high frequency circuits, the ground layer is added to make the signal line form a constant low impedance to the ground. The shielding effect is good. However, the more layers, the higher the cost, the longer the processing cycle, and the more troublesome the quality detection.
When you touch the FPC flexible circuit board has a guide/the problem of short circuit, the effective method that is under optical microscope inspection have line broken problem, most routes can penetrate electronic optical instruments and equipment could see, only to be met several times in work instance, under the light microscope can’t check out the route of broken problem, but with three meter measuring immediately gold fingers amount of area is able to detect the way, or by touching the intermittent.
In fact, there is no need to be surprised by such a result, because FPC is called flexible circuit board, because it is flexible and can bend, which is also the advantage and disadvantage of FPC, the disadvantage is that it can bend, because it may cause copper foil circuit to break. XPCB Co., Ltd. has domestic advanced production and testing equipment and experience, rich management team.
Our common computer board cards usually use four or six layers of board, but now there are more than 100 layers of practical printed circuit boards. The difference between the six-layer PCB and the four-layer PCB is that in the middle, that is, between the ground layer and the power layer, there are two more internal signal layers, thicker than the four-layer PCB.
Multi-layer PCB is actually etched by several single or double plate after laminating, bonding and become. The double plate are easy to distinguish and are transparent to the light except for the wiring on both sides. For the four and six layers, because the layers in the PCB are very close together, if there is a corresponding mark on the board, there is no good way to distinguish.
The design of through hole is an important factor. It consists of hole, pad area around hole and isolation area of POWER layer. It is usually divided into three categories: blind hole, buried hole and through hole. Through the analysis of the parasitic capacitance and parasitic inductance of the through-hole in the process of PCB design, some points for attention in the design of high-speed PCB through-hole are summarized.
Although the size of the pad and through hole has gradually decreased, if the thickness of the plate does not decrease in proportion, the aspect ratio of the through hole will increase, and the increase of aspect ratio of the through hole will reduce the reliability. With the maturity of advanced laser drilling technology and plasma dry etching technology, it is possible to apply non-perforating small blind holes and small buried holes. If the diameter of these non-perforating guide holes is 0.3mm, the parasitic parameters brought by these holes are about 1/10 of the original conventional holes, which improves the reliability of PCB.
The PCB manufacturing process begins with a PCB “substrate” made of GlassEpoxy resin or similar material. The first step of production is to draw the on-line wiring between the parts. The method is to “print” the circuit negative of the designed PCB circuit board on the metal conductor by the way of negative transfer printing.
XPCB Limited is a premium PCB & PCBA manufacturer based in China.
We specialize in multilayer flexible circuits, rigid-flex PCB, HDI PCB, and Rogers PCB.
Quick-turn PCB prototyping is our specialty. Demanding project is our key capability.