scholarly journals Design-of-experiment analysis of non-destructive detachment of electric parts from printed circuit boards of mobile phones using a cross-flow shredder

2021 ◽  
Vol 134 ◽  
pp. 52-56
Author(s):  
Takao UEDA ◽  
Hideaki FUKUSAWA ◽  
Naoki SUNAHARA ◽  
Hiroshi YAMADA ◽  
Tatsuya OKI ◽  
...  
Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 362
Author(s):  
Nicolò Maria Ippolito ◽  
Franco Medici ◽  
Loris Pietrelli ◽  
Luigi Piga

The effect of a preliminary acid leaching for the recovery of gold by thiourea from printed circuit boards (PCBs) of spent mobile phones, was investigated. Preliminary leaching is aimed to recover copper in the leachate that would compete with gold in the successive leaching of the residue with thiourea, thus preventing the formation of the gold-thiourea complex. Two hydrometallurgical routes were tested for the recovery of copper first, and gold after. The first one was based on a two-step leaching that utilizes sulfuric acid and hydrogen peroxide in the preliminary leaching and then thiourea for the recovery of gold in the successive leaching: A copper and gold recovery of 81% and 79% were obtained, respectively. In the second route, nitric acid was used: 100% of copper was recovered in the leachate and 85% of gold in the thiourea successive leaching. The main operative parameters, namely thiourea and ferric sulphate concentrations, leach time, liquid-solid ratio, and temperature were studied according to a factorial plan strategy. A flowsheet of the processes was proposed, and a mass balance of both routes was obtained. Finally, qualitative considerations on the technical and economic feasibility of the different routes were made.


2017 ◽  
Vol 72 (5) ◽  
pp. 1231-1238 ◽  
Author(s):  
Vladislava Mičková ◽  
Silvia Ružičková ◽  
Dagmar Remeteiová ◽  
Martina Laubertová ◽  
Marianna Dorková

Author(s):  
Navid Asadizanjani ◽  
Sina Shahbazmohamadi ◽  
Mark Tehranipoor ◽  
Domenic Forte

Abstract Reverse engineering of electronics systems is performed for various reasons ranging from honest ones such as failure analysis, fault isolation, trustworthiness verification, obsolescence management, etc. to dishonest ones such as cloning, counterfeiting, identification of vulnerabilities, development of attacks, etc. Regardless of the goal, it is imperative that the research community understands the requirements, complexities, and limitations of reverse engineering. Until recently, the reverse engineering was considered as destructive, time consuming, and prohibitively expensive, thereby restricting its application to a few remote cases. However, the advents of advanced characterization and imaging tools and software have counteracted this point of view. In this paper, we show how X-ray micro-tomography imaging can be combined with advanced 3D image processing and analysis to facilitate the automation of reverse engineering, and thereby lowering the associated time and cost. In this paper, we demonstrate our proposed process on two different printed circuit boards (PCBs). The first PCB is a four-layer custom designed board while the latter is a more complex commercial system. Lessons learned from this effort can be used to both develop advanced countermeasures and establish a more efficient workflow for instances where reverse engineering is deemed necessary. Keywords: Printed circuit boards, non-destructive imaging, X-ray tomography, reverse engineering.


Author(s):  
Daechul Choi ◽  
Sooyoung Ji ◽  
Jaelim Choi ◽  
Miyang Kim ◽  
Eunju Yang ◽  
...  

Abstract In this paper, we demonstrate a case for non-destructive detection of submicron wide via-crack in printed circuit boards (PCBs) by using in-situ thermal chamber 3D x-ray computed tomography. The defect location is verified by a PFA (Physical Failure Analysis), and good agreement was made. This fault isolation method is proposed as a possible solution for identifying submicron cracks in PCB substrates during challenging investigations.


Sign in / Sign up

Export Citation Format

Share Document