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Since this modest beginning, designers have searched for a means of keeping these elements secure, durable and reliable until removal is required. Though this seems to be the goal most sought after, any weekend mechanic will swear that the opposite seems more often to be the rule, rather than the exception.
Fastener enhancement products have traditionally encompassed only the most basic of notions including cotter pins and deformed components for locking, and messy greases and anti-seize for lubricants. In the recent decades, higher tech adhesives, sealants and coatings have come into play, taking strides in the reliability and multitasking of fastener systems. Today, there are a variety of new, highly specialised product choices and wider utilisation opportunities for use on components, far beyond that of fasteners.
Fastener locking devices
Adhesives as locking elements can be most broadly subdivided into two general categories:
Pre-applied: Applied to the fastener en-masse by fastener coating services, long before the intended installation.
Bottled: Applied to the joint at the time of assembly.
Pre-applied products do not impart any direct performance properties that cannot be found in a bottle, however, the advantage is realised in the pre-application ‘delivery system’ itself. Time saved by pre-application of adhesives (and the resulting direct, economic payback) plus the assurance that an adhesive is not inadvertently missing from a joint, are indispensable benefits to mass assembly.
User applied, point of assembly materials
Modern fastener retaining took its biggest leap forward with the development of bottled, liquid thread-locking adhesive. Anaerobic adhesives, as they are sometimes called, are ‘triggered’ (or initiate reaction) by the absence of oxygen contact.
A full spectrum of choices of these types of products are available for the user – low strength, high strength, removable, permanent, high temperature, penetrating, high viscosity, low viscosity, thixotropic, fast cure, slow cure, low friction, red, green, yellow, blue and purple; just to begin the list. Regardless of grade, whether permanently retaining a stud in an engine block or installing a serviceable pipe plug in a refrigerator – they are all based on the same chemistry.
Recent innovations have come to this field that include a variety of non-anaerobic thread-locking materials offered by STS/Tectorius®. This includes a variety of user applied materials that mimic the hard to get pre-applied products – previously only available through professional service centres in large volume. In addition to easy to use packaging, many are friendly to special substrates, temperature sensitive platings and plastics, where anaerobic adhesives should never be used.
In addition to threaded fasteners, many of these new breed products are finding use in non-traditional types of applications on splines, pulleys and moving assemblies offering a ‘cushioning effect’ to mitigate squeak and rattle for NVH (noise, vibration and harshness) improvement.
-The 18th China(Guangzhou)Int’l Fastener
& Equipment Exhibition
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