Технология press-fit расширяет применение в робототехнике и системах ИИ благодаря высокой плотности интеграции

As press-fit is deployed across more applications, PCB interconnects must handle increasing levels of integration, power density and connector density, writes Michael Meckl. Figure 1: Cross-sectional comparison of soldered and press-fit PCB interconnects Press-fit technology has been part of the electronics industry for decades. Originally adopted in telecommunications and datacom infrastructure, it enabled thousands of PCB connections to be assembled without secondary soldering operations. Automotive manufacturers later embraced the approach as electronic content increased and production volumes grew, creating demand for interconnects capable of supporting highly automated assembly. Today, press-fit is being deployed across industrial automation, energy infrastructure, AI computing systems and advanced robotics. These sectors place different demands on electronic systems. How press-fit works A press-fit connection is formed by inserting a compliant terminal into a plated through-hole in a PCB. During insertion, the compliant section deforms elastically, generating force against the copper-plated barrel. This creates both mechanical retention and electrical continuity without requiring a solder joint (Figure 1). The compliant section acts as a spring, generating the contact force required to maintain both electrical continuity and mechanical retention. As it is pressed into the plated through-hole, the compliant section flexes against the copper barrel, creating a stable metal-to-metal interface. Too little force can affect long-term contact stability. Too much force can damage the plated through-hole or surrounding laminate. Electrical requirements vary significantly between applications. Some press-fit interconnects carry low-level signals in high-density connectors, while others form part of power distribution architectures carrying substantially higher currents. As current levels increase, contact resistance, temperature rise and material selection become increasingly important. Different applications place different demands on the compliant section. CuNiSi alloys are widely used in press-fit applications because they balance conductivity and spring performance. Phosphor bronze alloys such as CuSn4, CuSn5, and CuSn6 provide even stronger spring characteristics, although conductivity is typically lower. For higher-current applications, CuCrZr alloys can achieve conductivity approaching the annealed copper baseline, making them well suited to designs where electrical and thermal performance are the primary considerations. Variation and wear Reliable press-fit performance depends on much more than compliant pin design. Hole diameter and plating thickness directly influence insertion force and contact pressure. Variations that appear insignificant on a drawing can affect how the compliant section behaves during insertion and how much force is retained over the life of the connection. Thermal cycling, vibration and material stress relaxation can gradually reduce contact pressure, particularly in applications expected to operate for years in demanding environments. As service life increases and assemblies become more densely packed, engineers must also account for long-term reliability risks such as oxidation and tin whisker formation when selecting terminal finishes (Figure 2). Figure 2: Tin whiskers remain a major reliability concern across the electronics sector Press-fit systems are typically developed using a combination of simulation, laboratory testing, and process validation to ensure insertion forces, contact pressures, and electrical performance remain within specification throughout the product lifecycle. Long-term performance Generating sufficient contact force while limiting stress within the plated through-hole requires careful control of geometry, material properties and insertion characteristics. One example is ENNOVI’s eye-of-the-needle (EON) compliant pin geometry (Figure 3). Finite element analysis (FEA) is used during development to evaluate stress distribution within the compliant section and optimise its behaviour during insertion and long-term operation. Figure 3: Finite element analysis shows the compliant section of an eye-of-the-needle press-fit pin deforms during insertion, generating the contact force required to maintain electrical continuity and mechanical retention Surface finish selection also affects terminal performance over time. Tin whisker formation remains a consideration in long-life electronic systems, particularly as connector density and electrical integration continue to increase. ENNOVI’s IndiCoat technology was developed to mitigate this risk. Performance ultimately depends on more than terminal design. Stamping, plating and insertion processes must be tightly controlled to ensure that performance demonstrated during qualification testing is maintained in production. Automotive validation at scale Few industries combine the environmental demands and production volumes of automotive electronics. Applications such as battery management systems, power distribution centres, Advanced Driver-Assistance Systems modules and vehicle control systems are expected to operate reliably over years of continuous service despite exposure to temperature cycling, vibration, and humidity. These requirements have shaped many of the qualification and manufacturing practices used throughout the press-fit industry. The industry standard IPC-9797 provide the foundation for evaluating press-fit performance, while many automotive manufacturers apply additional application-specific requirements based on their own reliability targets and operating conditions. Qualification programmes typically include insertion-force testing, contact resistance measurement, vibration testing, mechanical shock, temperature cycling, corrosion exposure, whisker evaluation and cross-sectional analysis of the plated through-hole. Many of the design approaches used in today’s press-fit systems were refined against these requirements. Press-fit pins in the field Deployments span signal connections in control electronics and higher-current power distribution architectures. Experience gained across billions of installed connections has helped refine compliant pin geometries, material selection, surface finishes, qualification methodologies and manufacturing processes. Looking ahead Press-fit technology is now being evaluated in applications far removed from its traditional telecom and automotive roots, including systems that combine high levels of electronic integration with demanding mechanical and environmental requirements (Figure 3). Figure 4: ENNOVI’s Press-Fit technology provides vibration-resistant electrical connectivity within dynamic mechanical assemblies In some sectors, serviceability is becoming increasingly important. Press-fit connections can simplify module replacement and repair by eliminating desoldering operations, reducing maintenance time and lowering the risk of damage to surrounding components during servicing. Higher currents, denser packaging, and increasing levels of electronic integration will continue to push interconnect design forward. The applications may be changing, but the requirements are familiar. Michael Meckl is product portfolio director, Signal, ENNOVI