| Résumé : |
Over the past 20 years, ultraviolet (UV)-curable adhesives and sealants have made continual strides in demanding, high-speed, high-volume applications. UV-curable materials offer reduced cycle times, smaller manufacturing footprints and less energy consumption. They are also safer to use in the workplace.
BACKGROUND
Rotating shaft seals are used in engine, transmission and axle-sealing applications. Each seal consists of an elastomer element bonded to a metal ring or case. In some designs, the outer diameter of the metal case is exposed. When the seal is installed into the bore of the engine or transmission block, the rough surface of the bore presents a potential fluid path that could ultimately lead to a leak of the service fluid. To eliminate this leak path, a secondary sealant is applied to the outer diameter of the metal case (see Figure 1).
Traditionally, this sealant has been a nitrile rubber dissolved in a flammable solvent. After application of the sealant, the seals are either passed through an oven to speed the evaporation of the solvent or are kept in a vented hood until dry, creating a high level of work in process (WIP), a demand on floor space, and, when ovens are used, added capital and operating costs.
Thus, when design engineers sought a more viable process, the answer was a UV-curable sealant. But what does it take to introduce a new material into a high-volume application? The development of UV-curable sealants and adhesives requires a systematic approach that considers the interactions among the material, its application and the UV light source. |
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Accueil
Developing a UV-curable bore sealant in ADHESIVES & SEALANTS INDUSTRY (ASI), Vol. 19, N° 7 (07/2012)
