Multi-Material Structural Adhesives Drive Lightweighting Potential

More design engineers are relying on composite substrates in an effort to reduce costs and increase lightweighting possibilities in assembly. Compared to adhesives, traditional mechanical fasteners are not very effective with these materials because of their fatigue-limited stress absorption, and in many cases engineers have to make sacrifices to accommodate the restricted capabilities of a mechanical fastener. With the design engineer in mind, 3M™ (St. Paul, MN) has introduced Scotch-Weld™ Multi-Material Composite Urethane Adhesives DP6310NS and DP6330NS to their growing portfolio of structural adhesives. These versatile adhesives are a perfect place to start when using composites because of their universal application and ability to effectively lightweight assemblies for trucks, buses, RVs, specialty vehicles and passenger rail, and other markets like sporting goods and panels.

DP6310NS and DP6330NS were engineered to create durable bonds with minimal surface prep, between medium to high energy surfaces like carbon fiber, fiberglass, reinforced plastics and painted or unpainted metal. The fast and robust bonding power of these adhesives opens the door wide for design engineers to explore new design options. Tough, long-lasting bonds for dissimilar materials require products that are highly energy-absorbing. The moduli of these adhesives were formulated to provide high strength and durability for bonding composites to metals. There are several advantages of using these structural adhesives instead of traditional fasteners like screws, rivets and bolts. Drilling holes in a plastic substrate for a screw or bolt can lead to cracking and other premature failures. Adhesives maintain structural integrity and provide secure bonds across diverse metals, plastics and composites. Incorporating adhesives into automotive assemblies is an easy way to eliminate added weight from mechanical fasteners. Structural adhesives also improve the aesthetic finish of a design, while reducing the installation time and costs that accompany traditional joining methods.

“We see the use of composite materials in design as a growing trend, but often assembling these materials with mechanical fasteners is not efficient, economical or aesthetically-pleasing,” said Chris Enstrom, the marketing manager for structural adhesives at 3M. “The broad applicability of these structural adhesives makes them the new standard go-to products when it comes to composite bonding, especially within the transportation and sporting goods industries.” DP6310NS and DP6330NS are low-odor and conveniently available in two versions with varying handling times to fit the scope of assembly. The ten minute work life version is ideal for a speedy, targeted application, with declamp time of approximately 45 minutes. The 30 minute work life version, followed by a two-hour clamp time, is designed with a large surface application in mind. The extended cure time allows the user more time to work with the product and ensure a secure bond. Both the ten minute and 30 minute work life versions can generally be used without a primer, expediting the application process.

3M, 3M Center, Building 225-1S-15, St. Paul, MN 55144-100, 3M.com/compositebonding.