Chemical Fasteners
Fasteners with Adhesive Coating
Reactive system (adhesive systems)
- Microencapsulation - DIN 267, part 27
Complete coating of microencapsulated adhesive, which is activated by the screwing-in process and counteracts self-unscrewing after hardening.
Examples of use
- Precote 30-3
- Precote 80
- Scotch-Grip
Coating method
- Manual or mechanical
- Flowing, dripping
- Wave soldering
Viscosity control
- DIN cup
Product features (finished product, hardened adhesive)
- Reaction time when installed:
24-72 hours at RT
15-30 mins at 70°C
- Lock against self-loosening
- Vibration-proof
- High breakaway torque MLB/MA > 0.9
- Resistant to oils, grease, fuels
- Fail-safe from -30°C to 150°C
- Low coefficients of friction (product-specific)
Lubricated surfaces
- In the case of surfaces with integrated and/or additionally applied lubrication, the specified requirements must be met at room temperature.
- At higher temperatures, these values do not have to be met. The additional locking effect of the adhesive must be verified in a comparative test. The values of the MK-coated screws must be greater than the values of uncoated screws.
Fasteners with Locking Coating
Non-reactive systems (locking systems)
- DIN 267, part 28
- Complete, plastic spot or thread coating, which causes a locking effect when screwed in, and does not stop the connection from unscrewing but prevents complete loosening.
- With threads of: nylon, aramide, metal (Cu, Al)
DIN 267, part 28 screws with locking coating
Tuflok, Clemm-Loc, polyamide spot coatings and complete polyamide coatings
The locking coating is not a lock to prevent unscrewing (like an adhesive coating), rather a retainer.
The locking torque is not capable of preventing self-unscrewing in the event of a high pretensioning force. A balance is only achieved between the locking torque and the unscrewing torque with a low residual pretensioning force, and then the locking torque prevents the connection from unscrewing completely and falling apart.
The "blue spot" is also suitable where other systems fail technically or economically:
- For very small screws - from M 0.8
- For screws made of a hard material
- For screws that must not be weakened in the cross-section
- For threaded pins
Fastener with locking coating
- Standard coating
- Unless otherwise agreed, the coating length is 1.5 x d ±2P, measured from the end of the screw.
- The first 2-3 threads remain free in order to be screwed in better.
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