How to use Climbing frame punching machine Punch holes on the printed circuit board?

Punching holes on printed circuit boards, like drilling holes, is also a mechanical operation. However, the hole diameter accuracy, hole wall smoothness, and bonding pad and base plate layering are not as good as drilling. In general, large holes are easier to punch than small holes. For example, for holes less than 0.9mm in the reinforced paper base plate and reinforced glass cloth base plate, it is less than 1 Punching failure is common for 2mm holes. Therefore, Auto punching machine automatic Punching machine The load depends on the type of substrate and their cutting force. The paper substrate bears a cutting force of 1200psi, while the epoxy glass substrate bears a cutting force of 20000psi. Therefore, the paper base plate should be able to withstand the pressure of 16t. In order to improve the safety factor, 32t bearing pressure is often used. The compression resistance of epoxy glass substrate is 70% higher than that of paper based phenyl ester substrate. Even simple plates need high compression resistance. When the automatic punching machine is used, the edge of the copper foil is always tilted. Therefore, it is not advisable to design a circuit on both sides of the board, which will cause the pad to fall off. In addition, if the distance between holes is too small, cracks may appear. In this case, the operating procedure should be changed, and copper foil etching should not be carried out before punching. In this way, the copper foil can play a reinforcing role and help avoid cracks. It is used in mass production of consumer printed circuit board products, and this kind of printed circuit board uses paper based phenyl ester and epoxy based substrates. Another disadvantage of punching is pad delamination and substrate fracture at the connection hole. In addition, punching will lead to the formation of a conical hole with a fairly thick surface, so printed circuit boards that do not meet professional requirements have high requirements for the smoothness of the plated through hole surface.

In order to process, there must be a precise tolerance between the drill and the punch. Generally, for paper substrate, punching should be 0.002 - O. 004in larger than the drilling machine, while for glass substrate, it should be half of this tolerance. Figure 10-2 shows an example of the required tolerance between the drilling machine and punching. For paper benzol base plates (XXX and similar types), in order to avoid fragmentation, the temperature needs to be heated to 50-70 ℃ in advance before punching. For example, XXXPC and FR-2 base plates can be punched at room temperature as long as the temperature is higher than 20 '℃. Non woven reinforced glass substrates (epoxy and polyester) have good punching performance. Use 50 - 100 μ A smooth hole wall suitable for electroplating can be obtained with a die clearance of m.

The following techniques can reduce many problems in punching, such as pad layering.

1) Punching shall be carried out on the copper clad surface;

2) Etching shall be carried out before punching;

3) The punched pad must be large enough.

The number of printed circuit boards is enough, at least 2000, and punching will be economical. Therefore, large quantities of non plated through hole reinforced paper substrates are more suitable for punching, while others are suitable for drilling.

In the process of punching, the damage rate of small punching is high, because:

1) The alignment is not standard enough: it can be easily found through precision detection tools;

2) Poor design: This is usually because the punching hole is too small to meet the requirements