Causes of Process Problems Caused by PCB Pretreatment

The PCB pretreatment process seriously affects the quality of the manufacturing process. Human, machine, materials, and other conditions in the PCB pretreatment program may cause some problems, which need to be analyzed to achieve more effective operation.

1. The process of using pretreatment equipment, such as: inner layer pretreatment line, electroplating-copper pretreatment line, D/F, solder mask... etc.

2. Gold steel brushes with #600 and #800 brush wheels are usually used, which will affect the roughness of the circuit board surface, the length of the ink and the adhesion of the copper surface. However, if the brush wheel is used for a long time, if the product is not placed on the left and right sides, the phenomenon of dog bones is likely to occur. This will cause the circuit board surface to be rough and uneven, line distortion, and the color difference between the copper surface and the INK after printing is different, so a complete painting operation is required. Brush mark test should be done before the brush grinding operation. The width of brush mark should be between 0.8~1.2mm. After updating the brush, correct the level of the brush wheel and add lubricating oil regularly. If the brush grinding water, or the spray pressure is too small and the fan-shaped mutual angle is not formed, it is easy to produce copper powder. Slight copper powder will cause micro short circuit or unqualified high voltage test during finished product test.

Another problem prone to pre-treatment is the oxidation of the board surface, which will cause bubbles on the board or cavitation after H/A.

1. The position of the solid water retention roller in the pretreatment is incorrect, causing too much acid to be introduced into the cleaning area. If the number of subsequent washing tanks is insufficient or the amount of water injected is insufficient, acid residue on the surface of the board will be caused.

2. Poor water quality in the washing section or impurities will also cause foreign matter to adhere to the copper surface.

3. If the suction roller is dry or saturated with water, it will not be able to effectively take away the water on the product, which will make the residual water on the board and the residual water in the hole too much, and then the air knife cannot fully function. Most of the resulting vacuoles are in a lacrimal pattern near the through hole.

4. When the board temperature is still at the time of discharging, the board is stacked in stacks, which will oxidize the copper surface in the board.

SHENZHEN HOYOGO ELECTRONIC TECHNOLOGY CO., LTD. is an international, professional, reliable PCB manufacturer. We have 2 production bases with a monthly production capacity of 500,000 square meters. One-stop PCB product supply and solution. And HOYOGO have a management team with 25 years of average industry experience and reliable quality assurance.