PCB printing method stamp hole or V-CUT which is better?

To know which is the best PCB assembly way, we must first understand why the assembly is in order to meet the production needs, such as some customers' boards are too small, which does not meet the requirements of making fixtures, at this time, we need a variety of boards together for production. There are also some special-shaped PCB boards, and the assembly board is also to improve the utilization rate of the PCB board, so as to avoid waste and reduce costs. When SMT is applied, the welding efficiency of SMT can be effectively improved.

What are V-cuts and stamp holes?

V-cut refers to the V-shaped dividing line between two boards and between the board and the process edge, forming a "V" shape; Break apart after welding.

Stamp hole is the motherboard plate inside, the small board and the small board need to be connected between the tendon, in order to facilitate cutting, the tendon will be opened up some holes, similar to the stamp edge of the kind of hole.

Stamp hole and V-CUT these two ways to choose which is better? In fact, each has its own advantages, each has its own disadvantages.

When using a double-sided V-shaped groove, the depth of the V-shaped groove should be controlled at about 1/3 (the sum of the two sides of the groove), requiring accurate groove size and uniform depth.

When using the stamp hole, it should be noted that the edge should be evenly distributed around each piece of the board to avoid deformation due to uneven stress on the PCB board during welding.

The position of the stamp hole should be close to the inside of the PCB board to prevent the residual burr at the stamp hole after the separation of the board from affecting the customer's complete machine assembly. For irregular PCB boards such as circles, V-CUT can not be done, so it is necessary to use stamp holes to make panel connections, so stamp holes are used more in shaped plates.

kinhford Electronics is a circuit board manufacturer specializing in printed circuit board manufacturing, 20 years of focus on single, double sided, multi-layer circuit board production. Can provide FR4 hard board, FPC soft board, HDI board, metal substrate PCB proofing and mass production services.

1. Multi-layer wiring

High speed signal wiring circuit often has high integration and high wiring density, the use of multilayer board is not only necessary for wiring, but also an effective means to reduce interference. Reasonable selection of layers can greatly reduce the size of the printing board, can make full use of the middle layer to set the shield, can better realize the nearby grounding, can effectively reduce the parasitic inductance, can effectively shorten the transmission length of the signal, can greatly reduce the cross interference between the signals.

2. The less the lead bends, the better

The less lead bending between pins of high-speed circuit devices, the better. High-speed signal wiring circuit wiring lead is best to use a straight line, need to turn, can be used 45° line or arc turn, this requirement in the low-frequency circuit is only used to improve the strength of steel foil fixation, and in the high-speed circuit, to meet this requirement can reduce the high-speed signal external emission and mutual coupling, reduce signal radiation and reflection.

3. The shorter the lead, the better

The shorter the lead between the pins of the high-speed signal routing circuit device, the better. The longer the lead, the larger the value of the distributed inductance and distributed capacitance, which has a lot of influence on the passing of the high-frequency signal of the system, and also changes the characteristic impedance of the circuit, resulting in reflection and oscillation of the system.

4. The less alternations between lead layers, the better

The less interlayer alternations between pins of high-speed circuit devices, the better. The so-called "the less interlayer alternations of the leads, the better" means that the fewer holes used in the connection process of the components, the better. It has been measured that a pass hole can bring about 0.5pf of distributed capacitance, resulting in a significant increase in the delay of the circuit, and reducing the number of pass holes can significantly improve the speed.

5. Pay attention to parallel cross interference

High-speed signal wiring should pay attention to the "cross interference" introduced by the signal line in the short distance parallel line, if the parallel distribution cannot be avoided, a large area of "ground" can be arranged on the opposite side of the parallel signal line to greatly reduce the interference.