The harm caused by short circuit to circuit board manufacturers is quite serious. The dirty etching is an important cause of circuit board short circuit. It is a process that circuit board manufacturers must go through to find ways to improve the etching process to reduce short circuit, especially in the printed circuit board manufacturing process. In the process, the requirements of the etching process are becoming more and more refined.
The harm caused by the short circuit to the circuit board manufacturer is quite large, as small as burning components, and as large as scrapping the PCB circuit board. We can only avoid short circuit as much as possible, we must grasp every step of production, and not let go of every suspicious point during inspection. In the etching process, the aspects that usually cause the short circuit of the circuit board are: improper control of the parameters of the etching solution, and uneven thickness of the electroplating layer when the entire board is electroplated with copper, resulting in unclean etching.
一. The control of the parameters of the etching potion directly affects the quality of the circuit board to the etching. The following is a specific analysis of the etching solution of Shenzhen circuit board manufacturers:
1. PH value: controlled between 8.3~8.8, if the PH value is low, the solution will become viscous, the color will be off-white, and the etching rate will decrease. This situation will easily cause side corrosion, which is mainly controlled by adding ammonia water pH value.
2. Ammonium ions: controlled between 190~210gL, the content of chloride ions is mainly controlled by etching salt, which is composed of ammonium chloride and supplements.
3. Specific gravity: The specific gravity is mainly controlled by controlling the content of copper ions. Generally, the content of copper ions is controlled between 145~155g/L, and the test is performed every hour or so of production to ensure the stability of the specific gravity.
4. Temperature: Control at 48~52C. If the temperature is high, the ammonia gas will volatilize quickly, which will cause the pH value to be unstable, and most of the cylinders of the etching machine are made of PVC materials, and the temperature resistance limit of PVC is 55°C , Exceeding this temperature will easily cause the deformation of the cylinder, and even cause the etching machine to be scrapped, so an automatic temperature controller must be installed to effectively monitor the temperature to ensure that it is within the control range.
5. Speed: generally adjust the appropriate speed according to the thickness of the bottom copper of the plate.
In order to achieve the stability and balance of the above parameters, it is recommended to configure an automatic feeder to control the chemical components of the sub-liquid, so that the composition of the etching solution is in a relatively stable state.
How do circuit board manufacturers improve the short circuit caused by etching?
二. When the whole board is electroplated with copper, the thickness of the electroplating layer is uneven, which leads to the improvement method of unclean etching.
1. Fully automatic line production is realized during electroplating of the entire circuit board. At the same time, according to the size of the hole area, the current density per unit area (1.5~2.0A/dm2) is adjusted, and the electroplating time is kept as consistent as possible. At the same time, the cathode and anode baffles are added, and the use system of "electroplating edge strips" is formulated to reduce the potential difference.
2. If the full board electroplating of the circuit board is produced by a manual line, the large board needs to be electroplated with double clamps to keep the current density per unit area as consistent as possible. At the same time, a timing alarm is installed to ensure the consistency of the electroplating time and reduce the potential difference.
