ADVANCED MATERIALS & PROCESSES | OCTOBER 2025 26 Structural adhesives are indispensable in modern manufac- turing, especially in the assembly of optoelectronic systems such as advanced driver-assistance systems (ADAS) cameras, which are widely used in the automotive industry (Fig. 1). Smart cameras play a critical role in vehicle safety features like lane-keeping, collision avoidance, and adaptive cruise control. While the focus of this article is on automotive applications, similar adhesive bonding challenges and contamination risks are also relevant in other high-precision sectors such as aerospace, medical devices, and consumer electronics. These adhesives are designed to provide mechanical integrity, environmental resistance, and long-term durability. However, their performance can be severely compromised by surface contamination—particularly from silicones, which are commonly used in thermal interface materials and masking tapes. This article describes a case study in which adhesive failures were observed in smart camera assemblies during production. The adhesive, which had previously passed all environ- mental and mechanical validation tests, began to exhibit poor bonding to aluminum lens mounts. This unexpected failure prompted a comprehensive DETECTION OF SILICONE CONTAMINATION USING RAMAN SPECTROSCOPY IN ADHESIVE BOND FAILURES Raman spectroscopy enables rapid, nondestructive detection of silicone contamination in ADAS camera assemblies, enhancing failure analysis and improving manufacturing reliability. Aravinda Bommareddy,* ZF Group Electronics, Farmington Hills, Michigan *Member of ASM International stability, flexibility, and chemical inertness. However, their low surface energy makes them problematic in adhesive bonding applications (Fig. 2). When silicone residues are present on a substrate, they reduce the surface energy, preventing proper wetting and adhesion of bonding agents[1,2]. Even small amounts of silicone contamination can lead to a significant reduction in bond strength. This is because silicones create a barrier that prevents the adhesive from making intimate contact with the substrate. Contaminated surfaces often result in adhesion failure modes such as interfacial failure, where the adhesive does not bond to the substrate at all, or cohesive failure, where the bond within the adhesive itself is weak. investigation, ultimately revealing that silicone contamination was the root cause. UNDERSTANDING SILICONE CONTAMINATION Silicones, especially polydimethylsiloxane (PDMS), are widely used in manufacturing due to their thermal Fig. 1 — Views of advanced driver-assistance systems (ADAS) cameras. Fig. 2 — Illustration of silicone oil which could impact adhesive bonding.
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