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A state of the art proprietary method for aluminum-to-aluminum joining in the automotive industry is Resistance Spot Welding. However, with spot welding (1) structural performance of the joint may be degraded through heat-affected zones created by the high temperature thermal joining process, (2) achieving the double-sided access necessary for the spot welding electrodes may limit design flexibility, and (3) variability with welds leads to production inconsistencies. Self-piercing rivets have been used before; however they require different rivet/die combinations depending on the material being joined, which adds to process complexity. In recent years the introductions of screw products that combine the technologies of friction drilling and thread forming have entered the market. These types of screw products do not have these access limitations as through-part connections are formed by one-sided access using a thermo-mechanical flow screwdriving process with minimal heat.

As automotive technology rapidly provides advances in lighter weight designs and materials, the technology to fasten and join them must keep pace. This paper will explore two uniquely different fastening technologies that are being used to address some of today's demanding application challenges in plastics and thin steel and aluminum sheet. These are two areas of application that have historically provided few good options for designers, especially as they attempt to push the envelope with progressive, light weight designs. The first technology is self- tapping screws for plastics that, although not new, are now evolving to enable smaller bosses and shorter thread engagements, and incorporate light weight design options. Although dependent on the demands of the application, these screws can be produced in both steel and, now, lighter weight materials such as aluminum and plastic.