September AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | S E P T E M B E R 2 0 1 8 7 PROCESS TECHNOLOGY An orb spider makes glue as it works on a web. LASERS ENABLE 3D-PRINTED AEROSPACE PARTS Researchers from RMIT University , Australia, are developing laser technol- ogy to build and repair steel and titani- um parts in what they believe could be a breakthrough application for indus- try. The scientists are using laser met- al deposition technology to build and repair defense aircraft parts during a two-year collaboration with RUAG Aus- tralia and the Innovative Manufacturing Cooperative Research Centre . The new technology feeds metal powder into a laser beam and adds new material in a precise, web-like formation when the beam is scanned across a surface. The resulting metallurgical bond has me- chanical properties that either meet or exceed those of the original material. Researchers say that by enabling onsite repair and production of parts, nonadhesive layer between the glue and the surface to which it is meant to stick, inhibiting formation of adhesive bonds. To find a solution, researchers at The University of Akron, Ohio, are look- ing to spider silk. The sticky glue that coats the silk threads of spider webs is a hydrogel. A subject of intensive re- search for years, spider glue is one of the most effective biological adhesives found in nature. The team set out to ex- amine the secret behind the hygroscop- ic success of the common orb spider, Larinioides cornutus , and how it over- comes the primary obstacle of achiev- ing good adhesion in humid conditions where water could be present between the glue and target surface. Spider glue is made of three ele- ments—two specialized glycoproteins, a collection of low molecular mass or- ganic and inorganic compounds (LM- MCs), and water. The team discovered that these glycoproteins act as prima- ry binding agents to the surface. Glyco- protein-based glues have been identi- fied in other biological sources such as fungi, algae, and English ivy. The LMMCs in spider glue perform a previously un- known function of sequestering interfa- cial water, preventing adhesive failure. The team then determined it is the in- teraction of glycoproteins and LMMCs that governs the adhesive quality of the glue produced. The ability of the spider glue to overcome the problem of inter- facial water by effectively absorbing it is the key research finding that may en- able commercial development of new adhesives. uakron.edu . the technology could completely transform the con- cept of warehous- ing and trans- porting compo- nents for defense and other indus- tries. Currently, re- placement parts typically must be ordered from local or overseas stor- age and suppliers. Although the cur- rent project fo- cuses on military aircraft, it is potentially transferable to the civil aircraft, marine, rail, mining, and oil and gas industries. www.rmit.edu.au . SPIDER GLUE AND COMMERCIAL ADHESIVES Overcoming the effects of interfa- cial water is one of the main challenges facing developers of commercial adhe- sives. Interfacial water forms a slippery, Engineers test new laser-made aircraft parts on a fighter jet. Courtesy of RUAG Australia. BRIEF Steel Dynamics Inc., Fort Wayne, Ind., will invest $140 million in its Columbus Flat Roll Division, adding a third galvanizing line at the Columbus, Miss., facility. The new line will have an annual coating capability of 400,000 tons, producing gaug- es between 0.013 and 0.160 in. and widths between 36 and 72 in. Operations are expected to begin mid-year 2020. steeldynamics.com .