Seats, instrument panels, floor consoles, trim and other automotive interior components are attached with a wide variety of fasteners. ASSEMBLY magazine recently asked Bob Gordon, central regional manager at PennEngineering (Danboro, PA), a leading supplier of fasteners, to share his thoughts and observations on the subject.

What are the biggest interior assembly challenges facing automakers and suppliers?
Gordon: Packaging. The goal is to design as many creature comforts, including technological convenience and safety components, as possible into a limited area with an aesthetic look. This requires finitely designed components that fit together precisely and provide long-term function in the area of the automobile that is most scrutinized by the owner.

Many automakers and suppliers are scrambling to provide “green” interiors. Has this affected the types of fasteners used?
Gordon: Because the performance of our products is directly correlated to the materials into which they are installed, this movement may affect type and style of fastener traditionally used. The continued move toward modular assembly lends itself to that alteration as well. Improvements in the adhesives arena now make them viable considerations, depending upon the dynamics the joint will be exposed to and any concerns for long-term function and serviceability.

Automakers and supplies are busy developing and experimenting with a wide variety of alternative biomaterials and ecoplastics. Do any of these new materials pose any unique joining and assembly challenges?
Gordon: Certainly, the softer the parent material, the less robust the function, unless superior design minimizes the dynamics or increases the material’s capabilities through innovative shaping. The challenge here would be to provide cost-effective fasteners able to adhere themselves with integrity to provide threaded or snap-connect assembly and still be disposable with the parent material or at least removable prior to recycle.
The areas that may present opportunities for these types of materials might already lend themselves to adhesives. Perhaps some advancement in the development of those products is required to be able to function adequately with materials that are non-petroleum based. We have tested our product in quiet steel with good results and have a new product development team that would embrace a challenge to develop a new generation of fastener.

The auto industry is attempting to address the ongoing issue of BSR (buzz, squeak and rattle), which remains one of the biggest warranty issues. How are you addressing this challenge?
Gordon: Loose assemblies can occur for any number of reasons, such as faulty design, wrong fasteners, minimization of joint strength and material usage. The flush feature on most of our fasteners allows as much bearing surface interface as possible when mating two components. This spreads the load and allows the entire geometry of the component to be involved in its function, limiting any less than solid joint areas.
Because we displace parent material and virtually become part of what we penetrate, our fasteners are stationary, receiving loose hardware that can be held in place with thread locking material to prevent screws and nuts from coming loose. Standard parts can be customized to accommodate multiple layers of material; a center piece of nonmetallic material can be used to remove any potential metal-to-metal sound creation.