Active investigation continues on various alloys used to replace lead for soldering in electronics components. Use of lead has dropped since the Restriction of Hazardous Substances Directive took effect in July, 2006. Historically, interconnections in electronic components have been made using tin/lead solder formulations. Those materials melt at 183C, while the thermoset and thermoplastics used in electronics have temperature limits up to 235C. The glass transition temperature of FR-4, a common PCB material, is between 140-175C. The resin softens as temperatures rise. New lead-free alternates such as SAC become liquid at 217C. Other lead-free solders have even higher melting points, causing failures of laminates and thermoplastics. Materials suppliers are struggling to adapt, says James Hall of ITM Consulting, who gave an interesting overview of the issue during a conference session at National Manufacturing Week in Rosemont, IL. “Just increasing cross-linking in the modified epoxies used in laminates is not the way to go,” he says. Cross-linking increases the brittleness of the laminates, creating problems when the boards are drilled. Specialty thermoplastics, such as modified nylons, are also experiencing problems because of the high solder temperatures. Explorations continue on new plastics as well as new solder formulations, including significant use of dopants such as nickel and germanium that provide specific property enhancements for various reasons.
An MIT research team has invented what they see as a solution to the need for biodegradable 3D-printable materials made from something besides petroleum-based sources: a water-based robotic additive extrusion method that makes objects from biodegradable hydrogel composites.
Alcoa has unveiled a new manufacturing and materials technology for making aluminum sheet, aimed especially at automotive, industrial, and packaging applications. If all its claims are true, this is a major breakthrough, and may convince more automotive engineers to use aluminum.
NASA has just installed a giant robot to help in its research on composite aerospace materials, like those used for the Orion spacecraft. The agency wants to shave the time it takes to get composites through design, test, and manufacturing stages.
The European Space Agency (ESA) is working with architects Foster + Partners to test the possibility of using lunar regolith, or moon rocks, and 3D printing to make structures for use on the moon. A new video shows some cool animations of a hypothetical lunar mission that carries out this vision.
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