3. Electroplating Pits
There are various processes that can lead to the formation of pits during electroplating, including copper immersion, pattern transfer, electroplating pretreatment, copper plating, and tin plating. Copper immersion is often caused by inadequate cleaning of the copper hanging basket over a prolonged period. During microetching, polluted liquid containing palladium copper may drip from the hanging basket onto the PCB surface, resulting in the formation of pits. Issues during the graphics transfer process are commonly due to poor equipment maintenance and inadequate cleaning. For example, contamination from glue stains on the brush roller suction stick of the brushing machine, internal contamination of the air knife fan in the drying section, improper dust removal before printing, and unclean developing and washing processes can all lead to pit formation on the PCB surface.
The pre-treatment process for electroplating is crucial, as the bath liquid primarily contains sulfuric acid. High water hardness can cause turbidity and surface contamination. Poor encapsulation of hangers in some companies can lead to dissolution and diffusion in the tank, resulting in non-conductive particles adsorbing on the board surface and potentially causing electroplating pits during subsequent processes.
4. Whitish or Uneven Color on Board Surface
Issues with the acid copper electroplating tank can manifest in various ways, such as uneven air agitation due to a deviation in the air blast tube position or air bubbles generated by a leaking filter pump. The use of inferior cotton cores in production can also lead to plating leakage from contamination by anti-static treatment agents. Addressing these issues promptly by cleaning up foam on the liquid surface and properly handling cotton cores can help prevent whitish or uneven color on the board surface.
Inadequate cleaning after acid degreasing, micro-etching problems, misadjustment of brightening agents, organic pollution, and high bath temperature can all contribute to surface discoloration. Micro-etching solutions with imbalanced content or temperature, poor water quality, prolonged washing, or contamination of pre-treatment solutions can cause oxidation issues on the board surface. Uneven coloration during copper bath electroplating may result from difficult oxide removal due to acidic oxidation, anode contact issues, or anode passivation.
Concluding Remarks
This article highlights common challenges in the acid copper plating process. Despite its widespread use for its simplicity and stability, proper troubleshooting and innovation are essential for improving craftsmanship and achieving high-quality coatings. Selecting and applying acid copper brighteners effectively is key to enhancing the plating layer’s brightness, leveling properties, and throwing power. Continuous learning and problem-solving in daily work are crucial for advancing craftsmanship and elevating the quality of electroplating processes.
There are various processes that can lead to the formation of pits during electroplating, including copper immersion, pattern transfer, electroplating pretreatment, copper plating, and tin plating. Copper immersion is often caused by inadequate cleaning of the copper hanging basket over a prolonged period. During microetching, polluted liquid containing palladium copper may drip from the hanging basket onto the PCB surface, resulting in the formation of pits. Issues during the graphics transfer process are commonly due to poor equipment maintenance and inadequate cleaning. For example, contamination from glue stains on the brush roller suction stick of the brushing machine, internal contamination of the air knife fan in the drying section, improper dust removal before printing, and unclean developing and washing processes can all lead to pit formation on the PCB surface.
The pre-treatment process for electroplating is crucial, as the bath liquid primarily contains sulfuric acid. High water hardness can cause turbidity and surface contamination. Poor encapsulation of hangers in some companies can lead to dissolution and diffusion in the tank, resulting in non-conductive particles adsorbing on the board surface and potentially causing electroplating pits during subsequent processes.
4. Whitish or Uneven Color on Board Surface
Issues with the acid copper electroplating tank can manifest in various ways, such as uneven air agitation due to a deviation in the air blast tube position or air bubbles generated by a leaking filter pump. The use of inferior cotton cores in production can also lead to plating leakage from contamination by anti-static treatment agents. Addressing these issues promptly by cleaning up foam on the liquid surface and properly handling cotton cores can help prevent whitish or uneven color on the board surface.
Inadequate cleaning after acid degreasing, micro-etching problems, misadjustment of brightening agents, organic pollution, and high bath temperature can all contribute to surface discoloration. Micro-etching solutions with imbalanced content or temperature, poor water quality, prolonged washing, or contamination of pre-treatment solutions can cause oxidation issues on the board surface. Uneven coloration during copper bath electroplating may result from difficult oxide removal due to acidic oxidation, anode contact issues, or anode passivation.
Concluding Remarks
This article highlights common challenges in the acid copper plating process. Despite its widespread use for its simplicity and stability, proper troubleshooting and innovation are essential for improving craftsmanship and achieving high-quality coatings. Selecting and applying acid copper brighteners effectively is key to enhancing the plating layer’s brightness, leveling properties, and throwing power. Continuous learning and problem-solving in daily work are crucial for advancing craftsmanship and elevating the quality of electroplating processes.
