Assembly Planbook - June 2008 - (Page 35)

which can damage the material. As plastics use proliferates in the appliance industry, “adhesive offers a competitive advantage over more traditional joining techniques,” says Doug Ellerbusch, adhesives marketing manager at Huntsman Advanced Materials (The Woodlands, TX). “This is especially true for polyurethane and methacrylate adhesives, which are tailor-made for bonding thermoplastics.” However, it’s difficult for plastic to compete with sheet metal on cost, strength and appearance in large parts, such as cabinets, tops and bases. As a result, big appliances, such as dishwashers, dryers, refrigerators, stoves and washing machines, still use large amounts of metal. The frames on those items are traditionally welded together. But, Wallach says alternate technologies have been investigated, such as bonding the frame housing. “[The industry is still tackling] the need for highstrength adhesives to set as quickly as traditional methods, such as welding,” he explains. “But, interesting developments with epoxies, particularly rapid curing via induction heating, are being explored as alternatives.” Due to widespread consumer demand, the appliance industry continues to favor stainless steel. “There has been a shift to alternative stainless steel grades to mitigate raw material cost increases,” says Lafond. “These CUSTOM PRODUCT TESTING SOLUTIONS Cincinnati Test Systems custom-engineered leak, assembly veriﬁcation and function test solutions are based on over 25 years of proven experience. We review each application to ensure you receive the best available technology. Our systems are designed to provide reliability, maximum uptime, longevity and seamless integration into your production environment. Joint Design Is Important When switching from mechanical fasteners to adhesive bonding, joint designs must be carefully reviewed and altered if necessary. As a result, most experts recommend applying structural adhesive only when engineers are creating new products. Adhesives depend on surface contact to create a bond to the substrate. Therefore, joints must be designed to give the adhesive as much surface contact as possible. Lap joints are the most commonly used adhesive joint and work best with metal applications. “Mechanically, you want to design the joint to load the bond in shear, not in peel,” warns David Speth, senior engineer at the Edison Welding Institute (EWI, Columbus, OH). While structural adhesives work with many different materials, the best product to use for a given application is generally a function of part design, processing needs and performance requirements. “Different substrates require different adhesives,” explains Speth. “Adhesives are particularly valuable if joining dissimilar materials, such as steel to other metals, metals to plastics, plastics to each other, or painted metals to anything else. “In general, you want the adhesive to be slightly less stiff than the substrates,” adds Speth. “Polyolefins and fluoropolymers are very difficult to bond. Only a few highly specialized adhesives work. Open cell foams have a low surface area for bonding.” Test us with your toughest product testing requirements! Helium Mass Spec Pressure Decay Mass Flow Assembly Veriﬁcation Functional Test A TASI Group Company 513.367.6699 providi n g w or l d-c l a s s l e ak t e s t a n d as s em bl y v e r i f i c a t i on s ol u t i on s s a l e s @ cincinna t i-t est . com cincinna t i-t est . co m www.assemblymag.com June 2008 / ASSE M B LY 35 http://cincinnati-test.com http://www.assemblymag.com

Table of Contents Feed for the Digital Edition of Assembly Planbook - June 2008

Assembly Planbook - June 2008 Contents Editorial Bonding Lines Quality in Assembly Assembly Lines Assembly in Action Fastening or Bonding? Loose Lips Sink Assembly Systems DFMA Cuts Downstream Costs Robots Lend a Hand Products Advertisers Index Classified Leading Lean

Assembly Planbook - June 2008

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