Cost and Reliability Implications of Selective Hard Gold Plating Techniques

Abstract

The demand for high-performance, durable edge connectors and switch contacts in Class 3 PCBs has led to the exploration of various selective hard gold plating techniques. Among these techniques, direct immersion and selective plating processes have garnered significant attention for their ability to provide consistent coating thicknesses, high electrical conductivity, and excellent wear resistance. However, the economic feasibility and reliability of these plating methods are subject to factors such as production cost, yield rates, and long-term durability. This study investigates the cost implications and reliability outcomes of these plating techniques, with a specific focus on their impact on Class 3 PCB applications. The research examines two key plating techniques: direct immersion and selective plating. Direct immersion is a simpler, lower-cost method, but challenges with uniform thickness and high gold usage have been identified as drawbacks. Selective plating, on the other hand, offers better control over plating thickness and can reduce gold waste, though it involves more complex equipment and higher upfront costs. This paper evaluates these methods through a comprehensive analysis of production costs, yield, and contact durability, aiming to determine the most cost-effective and reliable approach for manufacturing edge connectors and switch contacts. The findings are used to propose IPC-recommended guidelines for selective hard gold plating in Class 3 PCBs, addressing aspects such as acceptable plating thickness distributions, inspection criteria for quality assurance, and testing methodologies to validate durability and performance. These recommendations aim to assist manufacturers in selecting the appropriate plating techniques to balance cost, quality, and reliability, ensuring that edge connectors and switch contacts meet the demanding performance requirements of mission-critical applications.