This type of feature involves two possible methods of application, pre-applied and applied-in-place.
These features offer lower assembly torque than that achievable from prevailing torque type fasteners. Additionally, high breakaway torques are achieved due to the solid fill and adhesion from the adhesive coating after full cure.
Both pre-applied (micro-encapsulated) and applied-in-place (liquid) chemical adhesives offer the locking reliability characteristics of most other self-locking fastener types. However in-place chemical liquid application offers just ‘one-time’ use and additional assembly time is required to coat the fastener with the additive.
Downtime, application errors and contamination of other assembled parts are all inherent risks with in-place application of liquid chemical additive fasteners.
The pre-applied adhesives are usually anaerobic, or a two part epoxy, with the material positioned in a band around the threads and dry to the touch. When the fastener is rotated against its mating part, the capsules of adhesive burst, releasing the material in and around the thread flanks, which then cures and forms the locking bond. Since the adhesive coating is pre-applied, the assembly time for these fasteners is substantially less than for applied-in-place coatings, the bond is also more consistent.
Multiple reuse of a pre-applied chemical locking fastener is not recommended, since the relocking action depends upon the amount of reusable adhesive left on the bolt after the first installation. Most engineers design for one installation before the bolt must be re-coated, or replaced.
The Anochrome Group is able to offer a wide range of reactive locking patch, such as precote® 85, 80 and 30, 3M™ Scotchgrip®material 2353 and 2510 and Hyloloc 406 amongst many others. Each one of these materials offers a different combination of properties, sealing capacities, and temperature ranges to meet current automotive specifications such as WX200 and WX201 as well as Perkins, CAT, Jaguar Land Rover and others.
Precote is a registered trade mark of omniTECHNIK Mikroverkapselungs GmbH. Scotch-grip is a registered trade mark of 3M Company.
This refers to patch material applications where the parts are held horizontally and passed through a gravity fed stream of patch material.
This referes to the application of the patching material by rolling the parts across a controled feed of patch material, this generaly allows for tighter tolerances on patch position to be achieved.