Browse Publications Technical Papers 2008-01-1288

Integration of Fasteners and Inserts in Shape Molded Expanded Polyolefin Bead Foam Products for Automotive Interior Applications 2008-01-1288

The industry demand for improved material properties and performance, as well as the ever increasing demand for weight and cost reduction has presented challenges for the automotive industry as a whole. From the plastic materials side, the challenge has been incorporating new fastening and assembling technology into existing applications, all while reducing cost and improving performance.
This paper will explore new approaches for assembly and attachment methods for Shape Molded Expanded Polypropylene (EPP) Foam products used in automotive interiors. As EPP foam becomes more widely used throughout the automotive interior, it has become necessary to provide innovative ways of attachment and joining.
Recent innovations have allowed for the insert molding of EPP using wireframes, plastic inserts, metal brackets, and bars. As the use of EPP grows, it has become apparent that newer and more efficient methods of attachment are necessary such that secondary methods can be used to insert fasteners after completion of material molding.
This new development will facilitate ease of assembly, reduction of cost, and standardization of fastening and joining techniques, while attempting to commonize the types of fasteners employed for use with EPP.
Newer methods evaluated in this paper include ‘snap-in’ designs, press-fit fasteners, blind inserts, spin welded inserts, and multiple piece joining and attachment.
This paper will also evaluate the ability to ‘tune’ insert forces, and pull-out forces for specific component and part applications. A table of empirically derived insert and pull-out forces for fasteners typically used for expanded polyolefin foams [augers & “Christmas Tree” type fasteners] will be presented. All of this while meeting the industry need of both cost and weight reduction, and compliance to the stringent performance and environmental requirements of each OEM.


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