In this issue of Manufacturing Ideas to Watch: Magnetic Powered Refrigeration, Reversible Adhesives, Inexpensive Production of Polymer-Metal Nanocomposite, and Improved Metal Machinability. Let us know what you think by leaving a comment!
Magnetic Powered Refrigeration
Vacuum tubes to chips. Incandescent bulbs to LEDs. Internal combustion engine to fuel cells. These are clear examples of the advantages of solid state devices over conventional counterparts. Researchers at GE Appliances and Oak Ridge National Laboratory have set out to add refrigeration to the list. At the core of this work are magentocaloric materials (MCM)—materials that respond thermally to magnetic field variations and promise to deliver 25% more efficient cooling systems than vapor-compression systems. They also may enable smaller, quieter, and more reliable systems. A major challenge in building a solid state refrigerator is forming magnetocaloric materials, such as La-Fe-Si, into the right shape to respond to magnetic fields and to transfer heat effectively. The team is developing novel methods to create structures of MCM.
– -Ayyoub M. Momen, Oak Ridge National Laboratory
Reversible Adhesives for Structural Multi-material Joining
Adhesive joints have gained popularity due to their cost efficiency, light-weight designs, decreased stress concentrations, and ability to join dissimilar materials. However, adhesive-bonded joints commonly use thermoset adhesives, which are cured once and cannot be disassembled. A team at Michigan State University created a new adhesive that enables bonded joints with the ability to disassemble, repair and re-assemble. The new adhesive is composed of a thermoplastic material with embedded nano-scale or micro-scale particles, and works with any metal (aluminum, steel, magnesium, etc.), composite material or hybrid (multi-materials). Rapid, ‘targeted heating’ of the adhesive refreshes it, or allows it to be disassembled.
– Mahmoodul Haq, Michigan State University
Scalable and Inexpensive Production of Polymer-Metal Nanocomposite by Thermal Drawing
Polymers embedded with metallic nanoparticles (polymer-metal nanocomposites) have unique physicochemical properties valuable for enabling electrically conductive polymer-based materials for transparent electrodes, electromagnetic interface shielding and electrostatic dissipation, electromagnetic wave absorbers for solar cells, and antimicrobial surfaces. Optimal performance of polymer-metal nanocomposites requires uniform dispersion of the metallic phase, however processes to fabricate such uniform nanophase dispersions are a long-standing challenge, and the techniques available today are often costly and difficult to scale. UCLA researchers have developed a polymer-metal nanocomposite fabrication method that achieves a uniform dispersion of the metallic nanoparticles based on traditional thermal drawing techniques. By using an iterative stack, consolidate, and draw process, non-uniform microparticles are transformed to evenly dispersed nanoparticles.
– Xiaochun Li, UCLA
Improved Metal Machinability
Annealed metals are notoriously difficult to cut, causing diminished tool-life, poor surface finish, and tool chatter. During cutting, thick chips build up in front of the cutting tool, increasing the cutting force and degrading cutting performance. Researchers at Purdue University have developed a method to suppress chip nucleation by coating the surface of the metals with a thin layer of marking ink (metal marking ink, containing colored pigments, propanol, and diacetone alcohol). The researchers believe the ink works by reducing the sinuous flow, the repeated folding of material, in front of the the cutting tool. This coating process could be used to cut structural metals such as stainless steel or aluminum and integrated with existing machining units through the addition of a suitably positioned nozzle or brush.
– Srinivasan Chandrasekar, Purdue University
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