Gantry Roll Plating Production Line is a plating process where a certain number of small parts are placed in a special rotating drum. Through indirect conductivity, metal or alloy coatings are deposited on the surface of the parts while they are rotating. This process serves the purpose of surface protection, decoration, and achieving various functional goals. The details are as follows:
1. **Large Current Density Differences**
The cathode current density in roll plating is quite large; however, due to the significant differences in current density, most of the current is consumed by the parts with higher current density, resulting in a small average current density. As a result, the cathode current efficiency is low. If there is any neglect during operation, the coating thickness will be difficult to guarantee.
2. **Simultaneous Chemical Dissolution During Roll Plating**
When the parts roll, the current is intermittent, requiring extended plating time to achieve thicker coatings. However, the plating thickness at certain local areas remains hard to increase.
3. **Timely Adjustment of Main Salt Concentration**
The main salt in the roll plating solution consumes quickly, mainly due to insufficient anode area and the significant loss when parts exit the bath. When the main salt content is too low, it will lead to a decline in current efficiency, making it difficult to achieve a thicker coating. Therefore, timely adjustment should be made based on the chemical analysis data.
4. **Pre-treatment Difficulty of Roll Plated Parts**
Roll-plated parts can only be pre-treated in baskets, leading to overlapping and preventing thorough removal of contaminants. Consequently, the roll plating solution is easily contaminated, and due to the sensitivity of the solution to impurities, the purification workload is large, which often delays production.
5. **Significant pH Value Fluctuations in Roll Plating Solution**
The pH value fluctuation is especially significant during roll nickel plating. This is because hydrogen evolution is intense in certain areas during roll nickel plating. To maintain production stability, the pH value needs to be adjusted frequently.