Causes of corrosion of metal etching side

Why is there side corrosion in the metal etching process? The two most critical and at the same time the most important parameters in metal etching. The etching speed determines the length of the etching processing cycle. The faster the etching speed and the shorter the etching processing cycle, the higher the production efficiency, and vice versa. Generally speaking, hardware etching is a general term for metal etching, and for parts, it is called hardware etching. Because only the surface is etched, that is, it starts to contact the chemical liquid from the initial surface. At this time, due to the liquidity, the contact surface will diffuse to the periphery from the time of corrosion, forming side corrosion on the sidewall. At this time, the etching speed must be mastered. The etching speed will affect the final accuracy of the product. However, the hardware etching speed is not as fast as possible:

  1. The faster the etching speed, the greater the amount of metal etching in a unit time, the increase in heat generation, and the rapid change in the temperature of the corrosive liquid, which is not conducive to the constant etching speed;
  2. The etching speed is too fast, and it is not easy to control the processing of parts with very precise depth requirements;
  3. The faster the etching speed, the lower the quality of the etched metal surface, which obviously affects the smoothness and gloss of the etched surface;
  4. High etching speed often requires high concentration of etchant, highly corrosive chemical reagents, high etching temperature and so on. These factors increase the cost of the etchant, and at the same time increase the requirements for the resist layer and increase the cost.

Furthermore, high concentrations of corrosive agents and high etching temperatures will increase environmental pollution and harm to operators.
In practical applications, for those parts with a large amount of etching, the method of “fast first and slow later” can be adopted. The so-called “fast first and then slow” is to etch once with a faster etching solution. When the etching depth is close to the design requirement, then use a slower etching solution for precision etching. This will increase the process. , But shorten the processing time, while ensuring the etching accuracy and surface gloss. As for the determination of the fast etching time, it needs to be determined according to the processing requirements of the parts, generally 80%-90% of the total etching amount can be selected.

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