Horizontal Plating Technology for Printing Circuit Boards
Introduction
Printed circuit boards (PCBs) are commonly used in electronics and computer systems as a means to connect electric components. High quality standards have been introduced to ensure that PCBs meet their required performance criteria and are capable of taking high pressure and electrical loads. These high standards are particularly relevant for industries such as aerospace and automotive, which use these components in their more demanding applications. As a result, the PCB design and manufacturing process needs to be carefully considered to meet these requirements. One of the stages of PCB manufacture is the electroplating process, where metal layers are added to the board. Horizontal plating is a specialised process which is widely used in the PCB industry and offers a number of advantages over other types of plating process. This article provides an overview of the horizontal plating process, the associated equipment and the benefits of using this process.
Overview of Horizontal Plating Process
The horizontal plating process refers to the use of dipping tanks or large racks to plate a PCB from the top surface down. This type of plating can be used for both single-sided and multilayer boards, as well as for through-hole and surface mount devices. In the horizontal plating process, the boards are hung on the racks and then submerged in a plating solution. The entire surface of the board is exposed to the solution and then a current is passed through the solution to plate the board with the desired metal layer.
The horizontal plating process is the most common type of plating process used in the PCB industry and has been used for decades with very good results. There are several advantages of using horizontal plating compared to other methods, including:
• Easy to set up and run, as the process can be automated with very little user intervention;
• Cost effective, as it requires less space and equipment;
• More uniform plating, as the entire surface of the board is exposed to the solution;
• Better for higher density components, as the process allows for higher current densities;
• Less environmental impact, as the process does not involve hazardous chemicals or large vats of acid;
• Higher yields, as the plating quality is more consistent with the process;
• Quicker processing times, as there are no masking or etching steps involved;
• More accurate plating thicknesses, as the current is applied uniformly across the board; and
• Better repeatability, as the process is highly consistent.
Equipment Used
The equipment required for the horizontal plating process includes the following components:
• Plating tanks – These are open-topped tanks that use a mixture of metals and chemicals to create the desired level of plating.
• Racks – The racks are used to hang the boards in a vertical orientation during the plating process. The racks can be made from plastic, metal or coated wood.
• Anode – An electrolytic anode is used to create a current that will plate the boards.
• Cathode – The cathode is a metallic plate or mesh that is placed at the bottom of the tank. This serves to attract the positively charged ions from the solution and allows them to plate the boards.
• Heater – A heater is used to raise the temperature of the plating solution for optimal plating efficiency.
• Circulation pump – A specialised pump is used to circulate the solution in the tank and ensure that it remains constantly moving.
• Digital timer – A digital timer is used to control the plating times and the current.
• Filters – Specialised filters are used to remove impurities from the solution and ensure that the plating quality is consistently maintained.
Benefits of Horizontal Plating
The benefits of using the horizontal plating process are difficult to match with other plating technologies. By using the horizontal plating process, manufacturers are able to produce high quality and reliable boards in a fraction of the time that it would take to use other processes. Because of the uniformity of the plating process, yields are higher and errors are reduced, which results in cost savings for the manufacturer. Furthermore, the process does not require any masking or etching steps, which simplifies the overall PCB fabrication process and eliminates the need for costly and time-consuming manual processes. The process also offers very consistent plating thicknesses, which makes it ideal for higher density components and higher current densities.
Conclusion
The horizontal plating process is one of the most widely used plating processes in the PCB industry. The process offers a number of advantages over other plating methods, including cost savings, higher yields, shorter processing times and better repeatability. In addition, the process does not require any masking or etching steps, which further simplifies the production process. The process is suitable for both single-sided and multilayer boards and provides consistent plating thicknesses, which makes it ideal for higher density components. The process also has a lower environmental impact than other plating processes, as it does not involve hazardous chemicals or large vats of acid.
