3M™ Dual Lock™ Reclosable Fastener SJ3717, Black, Slide-in Piece Part, Stem Density 400

3M™ Dual Lock™ Reclosable Fastener SJ3717 is a black, polypropylene reclosable fastener with a 25.4 mm x 30.5 mm, slide-in, rectangular base and has a stem density of 400 stems per square inch. Dual Lock reclosable fastener SJ3717 overcomes the often difficult alignment and installation problems of screws and hidden fasteners, offering simple installation without requiring the use of special tools. 3M™ Dual Lock™ Reclosable Fasteners are positive-locking, blind fasteners designed for attaching automotive trim components. The products feature mushroom-shaped polyolefin stems that snap together, forming a high tensile closure. Dual Lock fasteners are used primarily to secure rigid and semi-rigid surfaces such as trim or door panels, instrument panel bezels, headliners, and other automotive interior and exterior trim.

3M™ Dual Lock™ Reclosable Fastener Slide-In Piece Parts attach without the use of pressure sensitive adhesive, and come with a variety of bases that can be slid into holes of precise dimension. They are easy to install and require no special equipment or skills.

How It Works
This pop-in fastener is designed to be inserted into a same-width channel where attachment is desired. The polypropylene base grips the inside of the channel and holds tight. The fastener can then be mated to a second Dual Lock fastener attached to a piece of trim or other part – when the two fasteners mate, the two parts are firmly secured together.

When two pieces of 3M™ Dual Lock™ Reclosable Fasteners are pressed together, the stems flex and the mushroom heads slide past each other. After passing the opposing mating piece, the stems snap back into their original position and the opposing mushroom heads interlock. These fasteners can provide high tensile strength but can be opened by simply cleaving or peeling open the closure.

Alignment and re-alignment are easy and no special tools are required. This means that Dual Lock fasteners can be used to attach components before they enter the final assembly plant, helping to reduce the number of parts and assembly time.

Stem Densities
Combinations of stem densities and the engaged area provide adjustable and proportional engagement and disengagement force to meet application needs. Dual Lock fasteners are offered in three different densities (stems per square inch): 170, 250, and 400. The Reclosable Fastener SJ3250 has 400 stems per square inch (25mm), offering the tightest hold, and can be mated to Type 170 or 250. It should not be mated with another Type 400 fastener because the engagement would be so tight that detachment would likely result in damage to the parts.

Recommended Applications
3M™ Dual Lock™ Reclosable Fasteners can replace conventional mechanical fasteners in a wide range of assembly and attachment applications where reclosability or serviceability is desired. Dual Lock fasteners are used primarily to secure rigid and semi-rigid surfaces such as trim or door panels, instrument panel bezels, headliners, and other automotive interior and exterior trim. Some examples of applications include:

• Vehicle headliners
• Attaching accessories and equipment
• Attaching window and door trim panels
• Vibration and sound damping control
• CHMSL cover plates
• Center console flanges
• Interior trim
• Sunroof rings