/pdf/database-for-solder-properties-with-emphasis-on-new-lead-yi4xacopk1.pdf

Database for Solder Properties with Emphasis on New Lead-free Solders

Soft robotic systems have applications in industrial, medical, and security applications. Many applications require these robots to be small and lightweight. One challenge in developing a soft robotic system is to drive multiple degrees-of-freedom (DOF) with few actuators, thereby reducing system size and weight. This paper presents the analysis and design of an inchworm-like mobile robot that consists of multiple, independent thermally activated joints but is driven by a single actuator. To realize control of this under-actuated system, a solder-based locking mechanism has been developed to selectively activate individual joints without requiring additional actuators. The design and performance analysis of a prototype mobile robot that is capable of inchworm-like translational and steering motion is described. The design of novel “feet” with anisotropic friction properties is also described.

Design and analysis of a soft mobile robot composed of multiple thermally activated joints driven by a single actuator

Magnetic nanoparticle-based solder composites for electronic packaging applications

For more than a decade, the use of lead (Pb) in electronics has been controversial: Indeed, its toxic effects are well documented, whereas relatively little is known about proposed alternative materials. As the quantity of electronic and electrical waste (e-waste) increases, legislative initiatives and corporate marketing strategies are driving a reduction in the use of some toxic substances in electronics. This article argues that the primacy of legislation over engineering and economics may result in selecting undesirable replacement materials for Pb because of overlooked knowledge gaps. These gaps include the need for: assessments of the effects of changes in policy on the flow of e-waste across state and national boundaries; further reliability testing of alternative solder alloys; further toxicology and environmental impact studies for high environmental loading of the alternative solders (and their metal components); improved risk assessment methodologies that can capture complexities such as changes in waste management practices, in electronic product design, and in rate of product obsolescence; carefully executed allocation methods when evaluating the impact of raw material extraction; and in-depth risk assessment of alternative end-of-life (EOL) options.



The resulting environmental and human health consequences may be exacerbated by policy differences across political boundaries. To address this conundrum, legislation and policies dealing with Pb in electronics are first reviewed. A discussion of the current state of knowledge on alternative solder materials relative to product design, environmental performance, and risk assessment follows. Previous studies are reviewed, and consistent with their results, this analysis finds that there is great uncertainty in the trade-offs between Pb-based solders and proposed replacements. Bridging policy and knowledge gaps will require increased international cooperation on materials use, product market coverage, and e-waste EOL management.

G.W.A. Dummer

Papers

Solders and Soldering