scholarly journals New Materials for SLS: The Use of Antistatic and Flow Agents

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Matthias Michael Lexow ◽  
Dietmar Drummer
Keyword(s):  
Mechanical Performance ◽  
Selective Laser Sintering ◽  
Powder Bed ◽  
Material Development ◽  
Particle Coating ◽  
Determining Factors ◽  
New Material ◽  
Complex Parts ◽  
Insight Into

Selective laser sintering (SLS) is a process based on the principle of a locally confined energy input by a laser into a powder bed, producing highly complex parts without the use of moulds or any other tools. In order to ensure good results for the processing behaviour of a new material, the powder must perform well during the phase of feeding the material into the process chamber which majorly influences the quality of the spread of the powder into the part bed and thus the mechanical performance of the final parts. In the present study, the principle of modification of fine powders with flow agents is applied aiming to enable the use of powders for SLS which are otherwise unsuitable due to poor flowability. In addition, the influence of antistatic agent on the powder flow and processing behaviour is discussed. The additives are found to strongly improve the flow behaviour at already very small contents and thus allow for processing of the composite material. The development of determining factors shares insight into the mechanisms of dry particle coating and its implementation into a growing market of material development.

scholarly journals A Comprehensive Investigation on 3D Printing of Polyamide 11 and Thermoplastic Polyurethane via Multi Jet Fusion

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2139
Author(s):  
Wei Shian Tey ◽  
Chao Cai ◽  
Kun Zhou
Keyword(s):  
Tensile Strength ◽  
Flexural Strength ◽  
Wear Rate ◽  
Mechanical Performance ◽  
Thermoplastic Polyurethane ◽  
Print Quality ◽  
Polyamide 11 ◽  
Powder Bed

Multi Jet Fusion (MJF) is a recently developed polymeric powder bed fusion (PBF) additive manufacturing technique that has received considerable attention in the industrial and scientific community due to its ability to fabricate functional and complex polymeric parts efficiently. In this work, a systematic characterization of the physicochemical properties of MJF-certified polyamide 11 (PA11) and thermoplastic polyurethane (TPU) powder was conducted. The mechanical performance and print quality of the specimens printed using both powders were then evaluated. Both PA11 and TPU powders showed irregular morphology with sharp features and had broad particle size distribution, but such features did not impair their printability significantly. According to the DSC scans, the PA11 specimen exhibited two endothermic peaks, while the TPU specimen exhibited a broad endothermic peak (116–150 °C). The PA11 specimens possessed the highest tensile strength in the Z orientation, as opposed to the TPU specimens which possessed the lowest tensile strength along the same orientation. The flexural properties of the PA11 and TPU specimens displayed a similar anisotropy where the flexural strength was highest in the Z orientation and lowest in the X orientation. The porosity values of both the PA11 and the TPU specimens were observed to be the lowest in the Z orientation and highest in the X orientation, which was the opposite of the trend observed for the flexural strength of the specimens. The PA11 specimen possessed a low coefficient of friction (COF) of 0.13 and wear rate of 8.68 × 10−5 mm3/Nm as compared to the TPU specimen, which had a COF of 0.55 and wear rate of 0.012 mm3/Nm. The PA11 specimens generally had lower roughness values on their surfaces (Ra < 25 μm), while the TPU specimens had much rougher surfaces (Ra > 40 μm). This investigation aims to uncover and explain phenomena that are unique to the MJF process of PA11 and TPU while also serving as a benchmark against similar polymeric parts printed using other PBF processes.

Study of Processing Conditions on the Forming of Ribbed Features Using Randomly Oriented Strands Thermoplastic Composites

2015 ◽  
Vol 60 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Dominic LeBlanc ◽  
Benoit Landry ◽  
Arthur Levy ◽  
Pascal Hubert ◽  
Steven Roy ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Filling Pressure ◽  
Thermoplastic Composites ◽  
Void Content ◽  
Component Level ◽  
Polyether Ether Ketone ◽  
Fast Processing ◽  
The Given ◽  
Complex Parts

Compression molding of randomly oriented strands (ROS) composites offers the possibility to manufacture complex parts with a fast processing cycle. In this paper, effects of pressure, strand size, temperature, and material placement in the mold cavity on the quality of a T-shape part were studied experimentally with carbon/polyether ether ketone ROS composites. Minimum filling pressure was obtained for the consolidation of a 25-mm deep cavity. Parts processed at filling pressure showed a void content no greater than 1.2%. Increasing pressure to 70 bar resulted in decreased void content as low as 0.03%. Mechanical testing of the T-shape showed similar strengths for parts processed at filling pressure and higher (70 bar). At the component level, initial strand placement greatly affected mechanical performance as the presence of a knit line was responsible for a reduction of 60% in tensile strength. The main findings show that processing a complex feature at filling pressure Pfill was sufficient to reach nominal mechanical properties. This suggested that moderate porosity was not detrimental to the mechanical performance for the given tests where fatigue performance was not evaluated.

scholarly journals User Adoption Of Internet Of Things: Determining Factors That Directly Affect Internet Of Things Service Adoption And Applying Them To An Existing System

2021 ◽  
Author(s):  
Revathi Gopalakrishnan
Keyword(s):  
Internet Of Things ◽  
Technology Acceptance ◽  
New Technology ◽  
Intention To Use ◽  
Service Adoption ◽  
User Adoption ◽  
Determining Factors ◽  
Acceptance Model ◽  
Insight Into

Internet of Things (IoT) is defined as a convergence of multiple technologies that interconnect physical and virtual objects over a network to improve our quality of life. These services deal with numerous interactions between devices, each having its own functionality and user flows. A large emphasis has always been placed on the technical aspects of IoT but very little importance has been given to researching factors that could have a significant effect on a user’s intention to use and adopt these services. Technology Acceptance Model (TAM) and Value-based Adoption Model (VAM) are two of the most widely used models to discovering the potential user’s intention to use a new technology. This paper examines these models to provide insight into determining factors that directly affect IoT service adoption by users and applies it to developing a coherent and engaging user interface for an existing IoT system.

scholarly journals Developing Tungsten-Filled Metal Matrix Composite Materials Using Laser Powder Bed Fusion

2020 ◽  
Vol 10 (24) ◽  
pp. 8869
Author(s):  
Martin Jäcklein ◽  
Aron Pfaff ◽  
Klaus Hoschke
Keyword(s):  
Metal Matrix ◽  
Steel Matrix ◽  
Matrix Composites ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Material Development ◽  
Production Techniques ◽  
New Material ◽  
Specific Material

The additive manufacturing technique laser powder bed fusion (L-PBF) opens up potential to process metal matrix composites (MMCs) with new material pairings free from limitations of conventional production techniques. In this work, we present a study on MMC material development using L-PBF. The generated composite material is composed of an X3NiCoMoTi 18-9-5 steel as matrix and spherical tungsten particles as filler material. A Design of Experiment (DoE)-based process parameter adaption leads to an Archimedean density close to the theoretical density in the case of 60 vol% tungsten content. A maximum ultimate tensile strength of 836 MPa is obtained. A failure analysis reveals a stable bonding of the tungsten particles to the steel matrix. This encourages the investigation of further material combinations. An additional heat treatment of the MMC indicates the potential to design specific material properties; it also highlights the complexity of such treatments.

scholarly journals User Adoption Of Internet Of Things: Determining Factors That Directly Affect Internet Of Things Service Adoption And Applying Them To An Existing System

2021 ◽  
Author(s):  
Revathi Gopalakrishnan
Keyword(s):  
Internet Of Things ◽  
Technology Acceptance ◽  
New Technology ◽  
Intention To Use ◽  
Service Adoption ◽  
User Adoption ◽  
Determining Factors ◽  
Acceptance Model ◽  
Insight Into

Internet of Things (IoT) is defined as a convergence of multiple technologies that interconnect physical and virtual objects over a network to improve our quality of life. These services deal with numerous interactions between devices, each having its own functionality and user flows. A large emphasis has always been placed on the technical aspects of IoT but very little importance has been given to researching factors that could have a significant effect on a user’s intention to use and adopt these services. Technology Acceptance Model (TAM) and Value-based Adoption Model (VAM) are two of the most widely used models to discovering the potential user’s intention to use a new technology. This paper examines these models to provide insight into determining factors that directly affect IoT service adoption by users and applies it to developing a coherent and engaging user interface for an existing IoT system.

A Small Feature-Sized Organic interposer for 2.1D Packaging Solutions

2014 ◽  
Vol 2014 (1) ◽  
pp. 000619-000623 ◽  
Author(s):  
Christian Romero ◽  
Jeongho Lee ◽  
Kyungseob Oh ◽  
Kyoungmoo Harr ◽  
Youngdo Kweon
Keyword(s):  
Mechanical Performance ◽  
Low Cost ◽  
Leading Edge ◽  
High Density ◽  
Material Development ◽  
Large Numbers ◽  
New Material ◽  
Small Feature ◽  
Global Interconnects ◽  
The Impact

The continuing advancement of semiconductor devices steadily increase the number of global interconnects and higher I/O counts thus driving more the importance of smaller feature size interconnects. One of the most difficult technical challenge for interconnects involves new material development, however, it is believed that mitigation of the impact of size scaling such as its aspect ratio (thickness/width) and spacing could fill the gap for high dense packaging requirement brought by Moore's Law. The next generation substrate design rules require a process capability with less than 50um pitch to accommodate leading-edge mobile applications such as Wide I/O memory-Logic packaging integration. In this paper, we describe an organic interposer that is capable of providing high density interface between chips with large I/O counts therefore could be an attractive low-cost 2.1D packaging solution. Our concept can demonstrate ultra fine line interconnects with width/space below 5um with microvias having pitch below 50um which can be effective solution for high density routing. This feature enables the ICs to be attached directly to the substrate therefore eliminating the need for a silicon interposer needed in conventional 2.5D package architecture. Microvia formation using photo-imageable material is another key feature of our organic interposer offering favorable cost efficiency for designs requiring very large numbers of microvias. The buildup layers could be vertically connected by microvias with min. 10um diameter using this process. Aside from the simplicity in supply chain, the high density organic interposer has the potential to meet both power and bandwidth requirement therefore can be considered an incremental move from conventional system-in-package providing flexibility in performance and yield capacity that allows integration of advanced logic and memory devices. We will present our various feasibility results of electrical/mechanical performance obtained from our fabricated test vehicles.

Attitudes of Elderly People in the South Moravian Region to Further Education

2014 ◽  
Vol 4 (2) ◽  
pp. 54-78
Author(s):  
Petr Adamec ◽  
Marián Svoboda
Keyword(s):  
Quality Of Life ◽  
Elderly People ◽  
Further Education ◽  
The South ◽  
The Third ◽  
Interesting Insight ◽  
Survey Results ◽  
Insight Into ◽  
Demographic Features

This paper deals with the results of sociological survey focused on identification of the attitudes of elderly people to further education. The research was carried out in September 2010. Experience of elderly people with further education, their readiness (determination) for further education as well as their motivation and barriers in further education were also subjects of this research. Detecting elderly population’s awareness of universities of the third age and finding out their further education preferences were an integral part of the research. Research sample consisted of citizens over 55 years living in the South Moravian region. The survey results are structured by socio-demographic features e.g.: age, sex, educational attainment etc. and provide an interesting insight into the attitudes of the target group to one of the activities that contributes to improvement of their quality of life.

scholarly journals Comparisons among rainbow trout, Oncorhynchus mykiss, populations of maternal transcript profile associated with egg viability

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Gregory M. Weber ◽  
Jill Birkett ◽  
Kyle Martin ◽  
Doug Dixon ◽  
Guangtu Gao ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Egg Quality ◽  
Transcript Abundance ◽  
Differentially Expressed ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Analysis Group ◽  
Maternal Transcripts ◽  
Single Batch ◽  
Insight Into

Abstract Background Transcription is arrested in the late stage oocyte and therefore the maternal transcriptome stored in the oocyte provides nearly all the mRNA required for oocyte maturation, fertilization, and early cleavage of the embryo. The transcriptome of the unfertilized egg, therefore, has potential to provide markers for predictors of egg quality and diagnosing problems with embryo production encountered by fish hatcheries. Although levels of specific transcripts have been shown to associate with measures of egg quality, these differentially expressed genes (DEGs) have not been consistent among studies. The present study compares differences in select transcripts among unfertilized rainbow trout eggs of different quality based on eyeing rate, among 2 year classes of the same line (A1, A2) and a population from a different hatchery (B). The study compared 65 transcripts previously reported to be differentially expressed with egg quality in rainbow trout. Results There were 32 transcripts identified as DEGs among the three groups by regression analysis. Group A1 had the most DEGs, 26; A2 had 15, 14 of which were shared with A1; and B had 12, 7 of which overlapped with A1 or A2. Six transcripts were found in all three groups, dcaf11, impa2, mrpl39_like, senp7, tfip11 and uchl1. Conclusions Our results confirmed maternal transcripts found to be differentially expressed between low- and high-quality eggs in one population of rainbow trout can often be found to overlap with DEGs in other populations. The transcripts differentially expressed with egg quality remain consistent among year classes of the same line. Greater similarity in dysregulated transcripts within year classes of the same line than among lines suggests patterns of transcriptome dysregulation may provide insight into causes of decreased viability within a hatchery population. Although many DEGs were identified, for each of the genes there is considerable variability in transcript abundance among eggs of similar quality and low correlations between transcript abundance and eyeing rate, making it highly improbable to predict the quality of a single batch of eggs based on transcript abundance of just a few genes.

scholarly journals Smoothing additive manufactured parts using ns-pulsed laser radiation

2021 ◽  
Author(s):  
Florian Kuisat ◽  
Fernando Lasagni ◽  
Andrés Fabián Lasagni
Keyword(s):  
Surface Roughness ◽  
Mechanical Performance ◽  
State Of The Art ◽  
Pulsed Laser ◽  
Industrial Applications ◽  
Laser Source ◽  
Pulsed Laser Radiation ◽  
Current State ◽  
The Impact

AbstractIt is well known that the surface topography of a part can affect its mechanical performance, which is typical in additive manufacturing. In this context, we report about the surface modification of additive manufactured components made of Titanium 64 (Ti64) and Scalmalloy®, using a pulsed laser, with the aim of reducing their surface roughness. In our experiments, a nanosecond-pulsed infrared laser source with variable pulse durations between 8 and 200 ns was applied. The impact of varying a large number of parameters on the surface quality of the smoothed areas was investigated. The results demonstrated a reduction of surface roughness Sa by more than 80% for Titanium 64 and by 65% for Scalmalloy® samples. This allows to extend the applicability of additive manufactured components beyond the current state of the art and break new ground for the application in various industrial applications such as in aerospace.

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