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Written by Mike Buetow and Chelsey Drysdale   
Saturday, 31 August 2013 01:03

3D Printing
Devices from the Printer?
Abstract: A few months ago came warnings of new 3D printer technology. For only a few hundred dollars, one could acquire a working printer, some raw material and a suitable computer program and then restore with this equipment guns and other weapons and abuse for terrorist purposes. In fact, complex mechanical structures can be implemented with 3D technology today. A 3D printer for home use that produces stable, functional equipment seems less fantasy than reality. For instance, some 30% of all components of an Airbus are manufactured with this technology. However, what’s not yet used are parts that are exposed to large mechanical and thermal loads. (Leuze Verlag, August 2013)

“Multi-Physics Addresses Electronics Design Challenges”
Author: Laura Bowen
Abstract: Conceptualization using simulation software is becoming important earlier in the design process, allowing engineers to verify and optimize their design before building a prototype. (Electronic Product Design & Test, August 2013)

Flex Circuits
“Effect of High-Humidity Testing on Material Parameters of Flexible Printed Circuit Board Materials”
Authors: Sanna Lahokallio, Kirsi Saarinen and Laura Frisk; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
Abstract: The tendency of polymers to absorb moisture impairs especially their electrical and mechanical properties. These are important characteristics for printed circuit board materials, which should provide mechanical support, as well as electrical insulation, in many different environments in order to guarantee safe operation for electrical devices. Moreover, the effects of moisture are accelerated at increased temperatures. In this study, three flexible PCB dielectric materials, namely polyimide (PI), fluorinated ethylene-propylene (FEP), and polyethylene terephthalate (PET), were aged over different periods of time in a high-humidity test, in which the temperature was 85°C and relative humidity 85%. After aging, the changes in the structure of the polymers were studied by determining different material parameters, such as modulus of elasticity, glass transition temperature, melting point, coefficient of thermal expansion, water absorption, and crystallinity, and changes in the chemical structure with several techniques, including thermomechanical analysis, differential scanning calorimetry, Fourier-transform infrared spectroscopy, moisture analysis, and a precision scale. The results showed that PI was extremely stable under the aging conditions and therefore an excellent choice for electrical applications under harsh conditions. Similarly, FEP proved to be relatively stable under the applied aging conditions. However, its crystallinity increased markedly during aging, and after 6000hr. of aging, the results indicated oxidation. PET suffered from hydrolysis during the test, leading to its embrittlement after 2000hr. of aging. (Journal of Electronic Materials, September 2013)

Solder Reliability
“Failure Analysis of Board-Level Sn-Ag-Cu Solder Interconnections under JEDEC Standard Drop Test”
Authors: Bo Zhang, Jing Si Xi, Pin Kuan Liu and Han Ding; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
Abstract: This work investigates the board-level drop reliability of PCBs assembled using three chip-size packages subjected to Jedec standard drop test condition B. The acceleration and dynamic strain responses at several locations of the board-level package in the time and frequency domain are comprehensively investigated. The results in the time domain suggest that the dynamic response of the board-level package has two phases: forced vibration and free vibration. The maximum response occurs at the first half free vibration cycle. The acceleration response at the center of the PCB is larger than at the edges, whereas the dynamic strain response is just the opposite. The results in the frequency domain show that the first mode is fundamental. In addition, failure analysis is performed using the dye-and-pry test and cross-section test, suggesting that the brittle cracking occurs at the layer between the IC pad and the solder, not only through intermetallic compound (IMC) but also along the surface between the IC pad and IMC. (Journal of Electronic Materials, September 2013)

This column provides abstracts from recent industry conferences and company white papers. Our goal is to provide an added opportunity for readers to keep abreast of technology and business trends.

Last Updated on Tuesday, 03 September 2013 16:48




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