On the Formation Mechanisms of Adhering Layer during Machining Metal Material

2017 ◽  
Vol 749 ◽  
pp. 39-45 ◽  
Author(s):  
Xiao Qi Song ◽  
Yukio Takahashi ◽  
Wei Ming He ◽  
Tohru Ihara

Built-up Layer (BUL)/Built-up Edge (BUE) formed on the tool surface can be treated as a protective, thermal barrier or lubricant films especially in the extreme severe conditions when machining the metal materials, which can sustain the tool effective and wear resistance. In order to have a thorough understanding of the adhesion effect during machining, experiments have been carried out to investigate the performance and the formation mechanisms of adhering layer on the carbide tool in machining of aluminium alloys A6063, carbon steel S45C and difficult-to-cut hardened steel S45C (H-S45C). The morphology of tool adhered surface was examined by employing Scanning Electron Microscopy (SEM), the dimensions of adhering layer were measured by Laser Scanning Microscopy (LSM) and the elements on the tool were analyzed by Electron Probe Micro Analyser (EPMA), respectively. The atomic-scale cluster adhesive friction model is proposed to explain the tool-chip contact conditions, which considers the nature of the shear strain, shear strain rate and temperature distribution in the secondary deformation zone. The model is a dynamic model and the rate equation approach can be applied to estimate the formation process of adhering layer during machining. Results have shown that the adhering layer will give rise to BUL on the tool rake face and the BUE on the cutting edge and clearance face.

1995 ◽  
Vol 117 (4) ◽  
pp. 534-541 ◽  
Author(s):  
W. J. Endres ◽  
R. E. DeVor ◽  
S. G. Kapoor

The Dual-Mechanism Machining Force Model (DMMFM) developed in Part 1 of this paper is calibrated through a specially developed algorithm, then validated. The calibration results are used to study the total machining force predictive capabilities of both the traditional lumped shearing model and the DMMFM. It is shown that the Dual-Mechanism Approach contributes greatly to our ability to both physically explain the trends in the machining force data and to understand their implications. This is achieved through an interpretation of the individual rake face and clearance face forces that are predicted using the DMMFM. The interpretation is based on the relations of these rake face and clearance face forces to the process inputs resulting from their effects on the DMMFM coefficients through thermal energy generation and temperature, shear-strain level and shear-strain rate. Some implications of the knowledge of the individual rake face and clearance face forces, as predicted by the DMMFM, are also discussed.


Author(s):  
Thomas M. Jovin ◽  
Michel Robert-Nicoud ◽  
Donna J. Arndt-Jovin ◽  
Thorsten Schormann

Light microscopic techniques for visualizing biomolecules and biochemical processes in situ have become indispensable in studies concerning the structural organization of supramolecular assemblies in cells and of processes during the cell cycle, transformation, differentiation, and development. Confocal laser scanning microscopy offers a number of advantages for the in situ localization and quantitation of fluorescence labeled targets and probes: (i) rejection of interfering signals emanating from out-of-focus and adjacent structures, allowing the “optical sectioning” of the specimen and 3-D reconstruction without time consuming deconvolution; (ii) increased spatial resolution; (iii) electronic control of contrast and magnification; (iv) simultanous imaging of the specimen by optical phenomena based on incident, scattered, emitted, and transmitted light; and (v) simultanous use of different fluorescent probes and types of detectors.We currently use a confocal laser scanning microscope CLSM (Zeiss, Oberkochen) equipped with 3-laser excitation (u.v - visible) and confocal optics in the fluorescence mode, as well as a computer-controlled X-Y-Z scanning stage with 0.1 μ resolution.


Author(s):  
M. H. Chestnut ◽  
C. E. Catrenich

Helicobacter pylori is a non-invasive, Gram-negative spiral bacterium first identified in 1983, and subsequently implicated in the pathogenesis of gastroduodenal disease including gastritis and peptic ulcer disease. Cytotoxic activity, manifested by intracytoplasmic vacuolation of mammalian cells in vitro, was identified in 55% of H. pylori strains examined. The vacuoles increase in number and size during extended incubation, resulting in vacuolar and cellular degeneration after 24 h to 48 h. Vacuolation of gastric epithelial cells is also observed in vivo during infection by H. pylori. A high molecular weight, heat labile protein is believed to be responsible for vacuolation and to significantly contribute to the development of gastroduodenal disease in humans. The mechanism by which the cytotoxin exerts its effect is unknown, as is the intracellular origin of the vacuolar membrane and contents. Acridine orange is a membrane-permeant weak base that initially accumulates in low-pH compartments. We have used acridine orange accumulation in conjunction with confocal laser scanning microscopy of toxin-treated cells to begin probing the nature and origin of these vacuoles.


TAPPI Journal ◽  
2010 ◽  
Vol 9 (10) ◽  
pp. 7-15
Author(s):  
HANNA KOIVULA ◽  
DOUGLAS BOUSFIELD ◽  
MARTTI TOIVAKKA

In the offset printing process, ink film splitting has an important impact on formation of ink filaments. The filament size and its distribution influence the leveling of ink and hence affect ink setting and the print quality. However, ink filaments are difficult to image due to their short lifetime and fine length scale. Due to this difficulty, limited work has been reported on the parameters that influence filament size and methods to characterize it. We imaged ink filament remains and quantified some of their characteristics by changing printing speed, ink amount, and fountain solution type. Printed samples were prepared using a laboratory printability tester with varying ink levels and operating settings. Rhodamine B dye was incorporated into fountain solutions to aid in the detection of the filaments. The prints were then imaged with a confocal laser scanning microscope (CLSM) and images were further analyzed for their surface topography. Modeling of the pressure pulses in the printing nip was included to better understand the mechanism of filament formation and the origin of filament length scale. Printing speed and ink amount changed the size distribution of the observed filament remains. There was no significant difference between fountain solutions with or without isopropyl alcohol on the observed patterns of the filament remains.


2012 ◽  
Vol 11 (3) ◽  
pp. 669-674 ◽  
Author(s):  
Szabolcs Szilveszter ◽  
Botond Raduly ◽  
Szilard Bucs ◽  
Beata Abraham ◽  
Szabolcs Lanyi ◽  
...  

Author(s):  
Kristopher D. Staller

Abstract Cold temperature failures are often difficult to resolve, especially those at extreme low levels (< -40°C). Momentary application of chill spray can confirm the failure mode, but is impractical during photoemission microscopy (PEM), laser scanning microscopy (LSM), and multiple point microprobing. This paper will examine relatively low-cost cold temperature systems that can hold samples at steady state extreme low temperatures and describe a case study where a cold temperature stage was combined with LSM soft defect localization (SDL) to rapidly identify the cause of a complex cold temperature failure mechanism.


2009 ◽  
Vol 18 (1) ◽  
pp. 11-16
Author(s):  
E.V. Soldatenko ◽  
A.A. Petrov

The morphology of the copulatory apparatus and associated cuticular structures in Planorbis planorbis was studied by light microscopy, SEM, TEM and confocal laser scanning microscopy. The significance of these cuticular structures for the taxonomic status of the species and for the systematics of the family Planorbidae in general is discussed.


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