Technical Library | 2022-01-05 23:14:20.0
The process of copper recovery from waste printed circuit board has generated large amounts of non-metallic fraction (NMF) residue. In this research, the residue was recycled as a substitute for fine aggregates at 0%, 5%, 10%, 15%, and 20% to produce interlocking concrete blocks. Properties of the interlocking concrete blocks produced in this study, such as density, water absorption, compressive strength, were firstly examined and the selected mixes were further evaluated for the heavy metal leachability.
Technical Library | 2012-11-08 19:16:39.0
first published in the 2012 IPC APEX EXPO technical conference proceedings. Twenty-nine different cells phones have been disassembled, ground up, dissolved and analyzed for elemental content, mainly for information about the metals present in the phones, but also for some metalloids and non-metals. The paper will discuss the method used and propose possible sources in the telephones for certain elements of interest and the reasons for the interest in some of the elements.
Technical Library | 2009-02-04 21:49:02.0
One proven method used to treat clogged arteries employs tubular, mesh-like metal structures, known as stents, inserted into an affected artery to relieve the blockage. Bare metal stents often cause a condition called restinosis, the buildup of scar tissue around the stent, causing re-blockage. To counter this, polymer coatings containing drugs that are released over time are used to inhibit restinosis. Applying coatings to stents, which have intricate geometries, is challenging. Using ultrasonic atomizing spray nozzles has proven effective in achieving continuous and uniform coatings. This paper describes the unique nozzle designs employed, the methodology used, and the results obtained.
Technical Library | 2013-09-05 17:44:14.0
Surface plasmon polaritons (SPPs) are localized surface electromagnetic waves that propagate along the interface between a metal and a dielectric. Owing to their inherent subwavelength confinement, SPPs have a strong potential to become building blocks of a type of photonic circuitry built up on 2D metal surfaces; however, SPPs are difficult to control on curved surfaces conformably and flexibly to produce advanced functional devices. Here we propose the concept of conformal surface plasmons (CSPs), surface plasmon waves that can propagate on ultrathin and flexible films to long distances in a wide broadband range from microwave to mid-infrared frequencies.
Technical Library | 2013-10-03 16:05:39.0
Printed Circuit Board (PCB) is an essential component of almost all electrical and electronic equipments. The rapid growth of the use of such equipments has contributed enormously to the generation of large quantity of waste PCBs. The WPCBs not only contain valuable metals but also a large variety of hazardous materials. Conventional treatments of such WPCBs have their own limitations. By pyrolysis of WPCBs, it is not only possible to obtain the organic part of it as a fuel or useful chemical but can make further processing to recover metals much easier and efficient. In the present work, a kinetic study on the low temperature pyrolysis of WPCBs using a thermogravimetric analyser has been attempted...
Technical Library | 2022-01-05 23:10:11.0
Waste electrical and electronic equipment or e-waste generation has been skyrocketing over the last decades. This poses waste management and value recovery challenges, especially in developing countries. Printed circuit boards (PCBs) are mainly employed in value recovery operations. Despite the high energy costs of generating crushed and milled particles of the order of several microns, those are employed in conventional hydrometallurgical techniques. Coarse PCB pieces (of order a few centimetres) based value recovery operations are not reported at the industrial scale as the complexities of the internal structure of PCBs limit efficient metal and non-metal separation.
Technical Library | 2015-08-06 19:17:53.0
Fine pitch/fine feature solder paste printing in PCB assembly has become increasingly difficult as board geometries have become ever more compact. The printing process itself, traditionally the source of 70% of all assembly defects, finds its process window narrowing. The technology of metal blade squeegees, with the aid of new materials, understanding, and settings such as blade angle, has kept pace with all but the smallest applications, e.g., 200μ - .50 AR and 150μ - .375 AR, which have been pushing blade printing technology to its limits. Enclosed media print head technology has existed, and has been under increasing development, as an alternative to metal squeegee blade printing. Until recently, the performance of enclosed print heads had been comparable to the very best metal squeegees, but advances in enclosed print media technology have now made it a superior alternative to squeegee blades in virtually all applications.
Technical Library | 2009-10-14 21:17:47.0
Electrochemical migration (ECM) is defined as the growth of conductive metal filaments across a printed circuit board (PCB) in the presence of an electrolytic solution and a DC voltage bias. ECM, also known as dendritic growth, is a critical issue in the electronics industry because the intermittent failure behavior of ECM is a likely root-cause of the high occurrence of field failures identified as no trouble found (NTF)/could not duplicate (CND)
Technical Library | 2021-11-03 16:52:47.0
This paper proposes the integration of pulsed photonic sintering into multi-material additive manufacturing processes in order to produce multifunctional components that would be nearly impossible to produce any other way. Pulsed photonic curing uses high power Xenon flash lamps to thermally fuse printed nanomaterials such as conductive metal inks. To determine the feasibility of the proposed integration, three different polymer additive manufacturing materials were exposed to typical flash curing conditions using a Novacentrix Pulseforge 3300 system. FTIR analysis revealed virtually no change in the polymer substrates, thus indicating that the curing energy did not damage the polymer. Next, copper traces were printed on the same substrate, dried, and photonically cured to establish the feasibility of thermally fusing copper metal on the polymer additive manufacturing substrates. Although drying defects were observed, electrical resistivity values ranging from 0.081 to 0.103 Ω/sq. indicated that high temperature and easily oxidized metals can be successfully printed and cured on several commonly used polymer additive manufacturing materials. These results indicate that pulsed photonic curing holds tremendous promise as an enabling technology for next generation multimaterial additive manufacturing processes.
Technical Library | 2016-07-07 15:37:18.0
How susceptible are the metals used in modern electronics manufacturing to corrosion by common beverages? This is a question of interest, especially to manufacturers, retailers and to a certain extent end customers. In this study the dissolution of aluminum, copper, gold, iron, lead, nickel, SAC305 solder, silver, tin and zinc was examined. Individual foils of these materials were fully immersed in one of sixteen chosen beverages and heated for 3 days at 40°C. The resulting solutions were analyzed using ICP-OES. The data were examined in light of the known pH, conductivity and ionic contents of the beverages, determined in previous work. Conclusions about the relative susceptibility to corrosion of the various metals and the corrosive power of the different beverages are made.
