scholarly journals Soldering Electronics to Smart Textiles by Pulsed Nd:YAG Laser

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2429
Author(s):  
Sebastian Micus ◽  
Michael Haupt ◽  
Götz T. Gresser
Keyword(s):  
Printed Circuit Boards ◽  
High Growth ◽  
Growth Potential ◽  
Circuit Boards ◽  
Smart Textiles ◽  
Peeling Test ◽  
Different Types ◽  
Laser Soldering ◽  
Conductive Textile ◽  
High Growth Potential

Experts attest the smart textiles market will have high growth potential during the next ten years. Laser soldering is considered to be a good contacting method because it is a contactless process. For this reason, it is intended to investigate the contacting process of printed circuit boards (PCB) to isolated conductive textile strips by means of a ytterbium-doped fiber laser (1064 nm). During the investigation, the copper strands in the textile tape were stripped by the laser and soldered to the PCB without any transport of the textile. Therefore, we investigated different sets of parameters by means of a design of experiment (DoE) for different types of solder pastes. Finally, the joinings were electrically analyzed using a contact resistance test, optically with a REM examination, and mechanically using a peeling test.

Noise properties of thin-film Ni-P resistors embedded in printed circuit boards

2013 ◽  
Vol 61 (3) ◽  
pp. 731-735
Author(s):  
A.W. Stadler ◽  
Z. Zawiślak ◽  
W. Stęplewski ◽  
A. Dziedzic
Keyword(s):  
Thin Film ◽  
Printed Circuit Boards ◽  
Circuit Boards ◽  
Noise Component ◽  
Printed Circuit ◽  
Resistance Bridge ◽  
Different Types ◽  
Signal Path ◽  
Resistance Fluctuations ◽  
Made In

Abstract. Noise studies of planar thin-film Ni-P resistors made in/on Printed Circuit Boards, both covered with two different types of cladding or uncladded have been described. The resistors have been made of the resistive-conductive-material (Ohmega-Ply©) of 100 Ώ/sq. Noise of the selected pairs of samples has been measured in the DC resistance bridge with a transformer as the first stage in a signal path. 1/f noise caused by resistance fluctuations has been found to be the main noise component. Parameters describing noise properties of the resistors have been calculated and then compared with the parameters of other previously studied thin- and thick-film resistive materials.

scholarly journals Interfacial Reactions and Mechanical Properties of Sn–58Bi Solder Joints with Ag Nanoparticles Prepared Using Ultra-Fast Laser Bonding

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 335
Author(s):  
Gyuwon Jeong ◽  
Dong-Yurl Yu ◽  
Seongju Baek ◽  
Junghwan Bang ◽  
Tae-Ik Lee ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Printed Circuit Boards ◽  
Solder Joints ◽  
Interfacial Reactions ◽  
Circuit Boards ◽  
Ag Nps ◽  
Laser Bonding ◽  
Laser Soldering ◽  
Low Temperature Bonding

The effects of Ag nanoparticle (Ag NP) addition on interfacial reaction and mechanical properties of Sn–58Bi solder joints using ultra-fast laser soldering were investigated. Laser-assisted low-temperature bonding was used to solder Sn–58Bi based pastes, with different Ag NP contents, onto organic surface preservative-finished Cu pads of printed circuit boards. The solder joints after laser bonding were examined to determine the effects of Ag NPs on interfacial reactions and intermetallic compounds (IMCs) and high-temperature storage tests performed to investigate its effects on the long-term reliabilities of solder joints. Their mechanical properties were also assessed using shear tests. Although the bonding time of the laser process was shorter than that of a conventional reflow process, Cu–Sn IMCs, such as Cu6Sn5 and Cu3Sn, were well formed at the interface of the solder joint. The addition of Ag NPs also improved the mechanical properties of the solder joints by reducing brittle fracture and suppressing IMC growth. However, excessive addition of Ag NPs degraded the mechanical properties due to coarsened Ag3Sn IMCs. Thus, this research predicts that the laser bonding process can be applied to low-temperature bonding to reduce thermal damage and improve the mechanical properties of Sn–58Bi solders, whose microstructure and related mechanical properties can be improved by adding optimal amounts of Ag NPs.

scholarly journals Dismantling of Waste Printed Circuit Boards with the Simultaneous Recovery of Copper: Experimental Study and Process Modeling

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5186
Author(s):  
Szabolcs Fogarasi ◽  
Árpád Imre-Lucaci ◽  
Florica Imre-Lucaci
Keyword(s):  
Environmental Performance ◽  
Printed Circuit Boards ◽  
Electrochemical Process ◽  
Circuit Boards ◽  
Electronic Components ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Different Types ◽  
Leaching Solution ◽  
The Impact

The study was carried out with the aim to demonstrate the applicability of a combined chemical–electrochemical process for the dismantling of waste printed circuit boards (WPCBs) created from different types of electronic equipment. The concept implies a simple and less polluting process that allows the chemical dismantling of WPCBs with the simultaneous recovery of copper from the leaching solution and the regeneration of the leaching agent. In order to assess the performance of the dismantling process, various tests were performed on different types of WPCBs using the 0.3 M FeCl3 in 0.5 M HCl leaching system. The experimental results show that, through the leaching process, the electronic components (EC) together with other fractions can be efficiently dismounted from the surface of WPCBs, with the parallel electrowinning of copper from the copper rich leaching solution. In addition, the process was scaled up for the dismantling of 100 kg/h WPCBs and modeled and simulated using process flow modelling software ChemCAD in order to assess the impact of all steps and equipment on the technical and environmental performance of the overall process. According to the results, the dismantling of 1 kg of WPCBs requires a total energy of 0.48 kWh, and the process can be performed with an overall low environmental impact based on the obtained general environmental indexes (GEIs) values.

Nanovoid Formation at Cu/Cu/Cu Interconnections of Blind Microvias: A Field Study

2019 ◽  
Vol 2019 (1) ◽  
pp. 000492-000502 ◽  
Author(s):  
T. Bernhard ◽  
L. Gregoriades ◽  
S. Branagan ◽  
L. Stamp ◽  
E. Steinhäuser ◽  
...  
Keyword(s):  
Printed Circuit Boards ◽  
Structural Integrity ◽  
Weak Link ◽  
Critical Factor ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Different Types ◽  
Key Factor ◽  
Electrical Reliability ◽  
The Impact

Abstract A key factor for a high electrical reliability of multilayer High Density Interconnection Printed Circuit Boards (HDI PCBs) is the thermomechanical stability of stacked microvia interconnections. With decreasing via sizes and higher numbers of interconnected layers, the structural integrity of these interconnections becomes a critical factor and is a topic of high interest in current research. The formation of nanovoids and inhibited Cu recrystallization across the interfaces are the two main indications of a weak link from the target pad to the filled via. Based on TEM/EDX measurements on a statistically relevant number of stacked and blind microvias produced in the industrial field, different types of nanovoid phenomena are revealed at the Cu/Cu/Cu junction. The types of nanovoids were categorized relating to the time of appearance (before or after thermal treatment), the affected interfaces or layers and the impact on the Cu recrystallization. The main root causes for each void type are identified and the expected impact on the thermomechanical stability of the via junction is discussed.

scholarly journals The condition of forest stands on afforested agricultural land in the Orlické hory Mts

2017 ◽  
Vol 63 (No. 1) ◽  
pp. 1-8 ◽  
Author(s):  
Cukor Jan ◽  
Baláš Martin ◽  
Kupka Ivo ◽  
Tužinský Marek
Keyword(s):  
Agricultural Land ◽  
High Growth ◽  
Dry Mass ◽  
Growth Potential ◽  
Forest Stands ◽  
Tree Biomass ◽  
Humus Layer ◽  
The Status ◽  
Spruce Stands ◽  
High Growth Potential

The paper presents an evaluation of the growth of newly established forest stands on former agricultural land and furthermore describes the state of the upper part of the soils in these stands in comparison with neighbouring grassland in the Orlické hory Mountains. The new Norway spruce stands show an extremely high growth potential, usually significantly higher in comparison with areas forested for more generations/rotations. The formation of the surface humus layer also showed fast progress, the amount of dry mass of soil organic matter reaching values almost typical of permanently forested sites. The soils of newly afforested lands tend to resemble the status of forest soil – there was observed a process of acidification and nutrient depletion, probably connected with accumulation of the tree biomass.

High growth potential and nitrogen removal performance of marine anammox bacteria in shrimp-aquaculture sediment

Chemosphere ◽  
2018 ◽  
Vol 196 ◽  
pp. 69-77 ◽  
Author(s):  
Luong Van Duc ◽  
Bongkeun Song ◽  
Hiroaki Ito ◽  
Takehide Hama ◽  
Masashi Otani ◽  
...  
Keyword(s):  
Nitrogen Removal ◽  
High Growth ◽  
Growth Potential ◽  
Shrimp Aquaculture ◽  
Anammox Bacteria ◽  
High Growth Potential

A Long-Term Culture of Human Hepatocytes Which Show a High Growth Potential and Express Their Differentiated Phenotypes

1999 ◽  
Vol 256 (1) ◽  
pp. 184-191 ◽  
Author(s):  
Hiroshi Hino ◽  
Chise Tateno ◽  
Hajime Sato ◽  
Chihiro Yamasaki ◽  
Shigeru Katayama ◽  
...  
Keyword(s):  
High Growth ◽  
Human Hepatocytes ◽  
Growth Potential ◽  
Long Term Culture ◽  
High Growth Potential

An analysis of growth of different cattle genotypes reared in different environments

1984 ◽  
Vol 103 (1) ◽  
pp. 137-153 ◽  
Author(s):  
J. E. Frisch ◽  
T. E. Vercoe
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
High Growth ◽  
Environmental Stresses ◽  
Growth Potential ◽  
Gastrointestinal Helminths ◽  
Treatment Groups ◽  
Survival And Growth ◽  
Different Levels ◽  
High Growth Potential

SummaryCalves from three breeds, Brahman, Hereford × Shorthorn (HS) and Brahman × HS (BX), were divided equally into two groups, one of which was treated every 3 weeks from birth onwards to control ticks and gastrointestinal helminths, and one of which was untreated. Mortalities, growth rates and levels of resistance to environmental stresses that affected both mortality and growth under grazing conditions were recorded for all animals up to weaning (6 months) and for all males up to 15 months of age. The Brahmans were the most and the HS were the least resistant to environmental stresses, each of which was shown to depress growth in proportion to its magnitude and to contribute to the high mortalities of the HS. All breeds responded positively to parasite control with the greatest response in both survival and growth in the HS breed and the least response in the Brahman breed.Samples of males from the various breed-treatment groups were taken into pens where they were protected from environmental stresses and fed both low-quality pasture hay and high-quality lucerne hay ad libitum. Measurements were made of fasting metabolism, maintenance requirement, voluntary food intake and gain, variables related to the growth potential of each animal. The HS animals had the highest whilst the Brahmans had the lowest values for each variable.However, despite their low growth potential, the Brahmans had the highest growtli rate, and the HS, despite their high growth potential, had the lowest growth rate, when growth was measured in the presence of all environmental stresses. When parasites were controlled, growth rates were highest for the BX, the breed with intermediate growtli potential, and did not differ between the HS and Brahmans. These interactions arose because of the different contributions of resistance to environmental stresses and growth potential to growth rate measured at the different levels of environmental stresses. The relevance of these interactions to breed evaluation and cross-breeding is considered.Growth potential and resistance to environmental stresses were negatively correlated both between and within breeds, though the latter was biased by the effects of compensation. The influence of these relationships on the likely outcome of selection for increased growth rate, both between and within breeds, is discussed.

scholarly journals Automatic Solder Joint Defect Classification using the Log-Gabor Filter

2010 ◽  
Vol 97-101 ◽  
pp. 2940-2943 ◽  
Author(s):  
Nang Seng Siri Mar ◽  
Clinton Fookes ◽  
K.D.V. Yarlagadda Prasad
Keyword(s):  
Solder Joint ◽  
Manufacturing Industry ◽  
Printed Circuit Boards ◽  
Distance Measure ◽  
Gabor Filter ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Different Types ◽  
Gabor Filter Bank

This paper proposes the validity of a Gabor filter bank for feature extraction of solder joint images on Printed Circuit Boards (PCBs). A distance measure based on the Mahalanobis Cosine metric is also presented for classification of five different types of solder joints. From the experimental results, this methodology achieved high accuracy and a well generalised performance. This can be an effective method to reduce cost and improve quality in the production of PCBs in the manufacturing industry.

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