The key to PCB plating lies in ensuring the uniformity of copper layer thickness on both sides of the substrate and the inner walls of the vias. To achieve consistent plating thickness, it is crucial to maintain a rapid and uniform flow rate of the plating solution across the printed board and through holes, which facilitates the formation of a thin and even diffusion layer. Given the current structure of horizontal electroplating systems, despite having multiple nozzles, the plating solution must be sprayed quickly and vertically onto the printed board to enhance its flow through the vias. This rapid flow generates eddy currents on both the upper and lower surfaces of the substrate and within the vias, leading to a reduction in the diffusion layer thickness and achieving greater uniformity.
However, when the plating solution suddenly enters a narrow via, a reverse flow phenomenon can occur at the entrance, compounded by the effects of primary current distribution. This often results in an excessively thick copper layer at the entrance due to the tip effect, forming a dog-bone shape on the inner wall of the via. The state of the plating solution’s flow in the via, characterized by the size of the eddy currents and the backflow, is essential for analyzing the quality of the conductive plated through hole. Control parameters to ensure uniform PCB plating thickness can only be determined through process testing, as the sizes of the eddy currents and backflow cannot be accurately predicted through theoretical calculations. Thus, empirical measurement methods are necessary to assess these factors effectively.
1. It is well established that controlling the uniformity of the copper electroplating layer thickness in through-holes requires adjusting controllable process parameters based on the aspect ratio of the PCB through-hole. Furthermore, selecting a copper electroplating solution with high dispersibility and incorporating suitable additives, along with improved power supply methods—specifically, employing reverse pulse current for electroplating—can yield copper coatings with excellent distribution capabilities.
2. Notably, the prevalence of micro-blind holes in laminates has increased. This necessitates the use of a horizontal plating system for electroplating, as well as ultrasonic vibration to enhance the replacement and circulation of the plating solution within the micro-blind holes. By adjusting controllable parameters according to the data, satisfactory outcomes can be achieved.
3. Horizontal electroplating is characterized by a shift in the PCB placement method from vertical to a parallel configuration above the plating solution. In this setup, the PCB acts as the cathode, with many horizontal electroplating systems employing conductive clamps and rollers to supply current. For operational efficiency, the roller conductive supply method is commonly used. The conductive roller not only serves as the cathode but also facilitates PCB transport. Each conductive roller is equipped with a spring mechanism to accommodate the electroplating requirements of PCBs with varying thicknesses (0.10-5.00 mm). However, during the electroplating process, all components in contact with the plating solution may acquire a copper layer, potentially limiting the system’s operational lifespan. Consequently, most modern horizontal electroplating systems are designed to allow cathodes to switch to anodes, while auxiliary cathodes are employed to electrolytically dissolve copper from the plated rollers. Maintenance and replaceability are also considered in the new electroplating designs, focusing on parts that are prone to wear.
4. The anodes consist of an array of adjustable-size insoluble titanium baskets positioned above and below the PCB. These baskets are filled with 25 mm diameter spherical particles containing 0.004-0.006% phosphorus and soluble copper, maintaining a distance of 40 mm between the cathode and anode.
5. The flow of the plating solution is managed by a system of pumps and nozzles, enabling the solution to flow rapidly and alternately within the closed plating tank in both horizontal and vertical directions, ensuring uniform distribution. The plating solution is sprayed vertically onto the PCB, creating a wall-punching jet vortex across the surface. The ultimate goal is to achieve rapid flow of the plating solution on both sides of the PCB and through the holes to generate eddy currents. Additionally, a filter system, utilizing a 1.2-micrometer filter screen, is installed in the tank to eliminate particulate impurities generated during the electroplating process, ensuring a clean and pollution-free plating solution.
6. When designing a horizontal electroplating system, operational convenience and the automatic control of process parameters must also be prioritized. In practical electroplating scenarios, the size of the PCB, through-hole diameter, required copper thickness, transmission speed, distance between PCBs, pump horsepower, nozzle direction, and current density all necessitate careful testing, adjustment, and control to achieve the desired copper layer thickness. This process must be managed by a computer. To enhance production efficiency and ensure the consistency and reliability of high-end product quality, the through-hole processing (including plated holes) of the PCB should follow established procedures, creating a comprehensive horizontal electroplating system to support new product development and market introduction.
7. The above outlines the principles of horizontal electroplating. As high-speed PCB design and manufacturing evolve alongside horizontal electroplating, more demands will be effectively met.
If you have any PCB manufacturing needs, please do not hesitate to contact me.Contact me
However, when the plating solution suddenly enters a narrow via, a reverse flow phenomenon can occur at the entrance, compounded by the effects of primary current distribution. This often results in an excessively thick copper layer at the entrance due to the tip effect, forming a dog-bone shape on the inner wall of the via. The state of the plating solution’s flow in the via, characterized by the size of the eddy currents and the backflow, is essential for analyzing the quality of the conductive plated through hole. Control parameters to ensure uniform PCB plating thickness can only be determined through process testing, as the sizes of the eddy currents and backflow cannot be accurately predicted through theoretical calculations. Thus, empirical measurement methods are necessary to assess these factors effectively.
1. It is well established that controlling the uniformity of the copper electroplating layer thickness in through-holes requires adjusting controllable process parameters based on the aspect ratio of the PCB through-hole. Furthermore, selecting a copper electroplating solution with high dispersibility and incorporating suitable additives, along with improved power supply methods—specifically, employing reverse pulse current for electroplating—can yield copper coatings with excellent distribution capabilities.
2. Notably, the prevalence of micro-blind holes in laminates has increased. This necessitates the use of a horizontal plating system for electroplating, as well as ultrasonic vibration to enhance the replacement and circulation of the plating solution within the micro-blind holes. By adjusting controllable parameters according to the data, satisfactory outcomes can be achieved.
3. Horizontal electroplating is characterized by a shift in the PCB placement method from vertical to a parallel configuration above the plating solution. In this setup, the PCB acts as the cathode, with many horizontal electroplating systems employing conductive clamps and rollers to supply current. For operational efficiency, the roller conductive supply method is commonly used. The conductive roller not only serves as the cathode but also facilitates PCB transport. Each conductive roller is equipped with a spring mechanism to accommodate the electroplating requirements of PCBs with varying thicknesses (0.10-5.00 mm). However, during the electroplating process, all components in contact with the plating solution may acquire a copper layer, potentially limiting the system’s operational lifespan. Consequently, most modern horizontal electroplating systems are designed to allow cathodes to switch to anodes, while auxiliary cathodes are employed to electrolytically dissolve copper from the plated rollers. Maintenance and replaceability are also considered in the new electroplating designs, focusing on parts that are prone to wear.
4. The anodes consist of an array of adjustable-size insoluble titanium baskets positioned above and below the PCB. These baskets are filled with 25 mm diameter spherical particles containing 0.004-0.006% phosphorus and soluble copper, maintaining a distance of 40 mm between the cathode and anode.
5. The flow of the plating solution is managed by a system of pumps and nozzles, enabling the solution to flow rapidly and alternately within the closed plating tank in both horizontal and vertical directions, ensuring uniform distribution. The plating solution is sprayed vertically onto the PCB, creating a wall-punching jet vortex across the surface. The ultimate goal is to achieve rapid flow of the plating solution on both sides of the PCB and through the holes to generate eddy currents. Additionally, a filter system, utilizing a 1.2-micrometer filter screen, is installed in the tank to eliminate particulate impurities generated during the electroplating process, ensuring a clean and pollution-free plating solution.
6. When designing a horizontal electroplating system, operational convenience and the automatic control of process parameters must also be prioritized. In practical electroplating scenarios, the size of the PCB, through-hole diameter, required copper thickness, transmission speed, distance between PCBs, pump horsepower, nozzle direction, and current density all necessitate careful testing, adjustment, and control to achieve the desired copper layer thickness. This process must be managed by a computer. To enhance production efficiency and ensure the consistency and reliability of high-end product quality, the through-hole processing (including plated holes) of the PCB should follow established procedures, creating a comprehensive horizontal electroplating system to support new product development and market introduction.
7. The above outlines the principles of horizontal electroplating. As high-speed PCB design and manufacturing evolve alongside horizontal electroplating, more demands will be effectively met.
If you have any PCB manufacturing needs, please do not hesitate to contact me.Contact me
