Replication integrity of micro features using variotherm and vacuum assisted microinjection moulding

2018 ◽  
Vol 23 ◽  
pp. 20-38 ◽  
Author(s):  
Nan Zhang ◽  
Haoyang Zhang ◽  
Charlie Stallard ◽  
Fengzhou Fang ◽  
Michael D. Gilchrist
Keyword(s):  
Micro Features ◽  
Microinjection Moulding

Macro and Micro Features of Successful Economic Convergence

10.1596/31207 ◽  
2019 ◽  
Author(s):  
Marc Schiffbauer ◽  
Gonzalo Varela
Keyword(s):  
Economic Convergence ◽  
Micro Features

scholarly journals FEM and Analytical Modeling of the Incipient Chip Formation for the Generation of Micro-Features

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3789
Author(s):  
Michele Lanzetta ◽  
Marco Picchi Picchi Scardaoni ◽  
Armin Gharibi ◽  
Claudia Vivaldi
Keyword(s):  
Material Properties ◽  
Analytical Modeling ◽  
Cutting Tool ◽  
Sustainable Manufacturing ◽  
Cutting Parameters ◽  
Micro Machining ◽  
Machining Processes ◽  
Steel Alloys ◽  
Diamond Blade ◽  
Micro Features

This paper explores the modeling of incipient cutting by Abaqus, LS-Dyna, and Ansys Finite Element Methods (FEMs), by comparing also experimentally the results on different material classes, including common aluminum and steel alloys and an acetal polymer. The target application is the sustainable manufacturing of gecko adhesives by micromachining a durable mold for injection molding. The challenges posed by the mold shape include undercuts and sharp tips, which can be machined by a special diamond blade, which enters the material, forms a chip, and exits. An analytical model to predict the shape of the incipient chip and of the formed grove as a function of the material properties and of the cutting parameters is provided. The main scientific merit of the current work is to approach theoretically, numerically, and experimentally the very early phase of the cutting tool penetration for new sustainable machining and micro-machining processes.

scholarly journals Analysis of the Downscaling Effect and Definition of the Process Fingerprints in Micro Injection of Spiral Geometries

Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 335 ◽  
Author(s):  
Antonio Luca ◽  
Oltmann Riemer
Keyword(s):  
Correlation Analysis ◽  
Process Parameters ◽  
Cross Sections ◽  
Mass Production ◽  
Process Window ◽  
Response Variable ◽  
Process Indicators ◽  
Flow Length ◽  
Definition Of ◽  
Microinjection Moulding

Microinjection moulding has been developed to fulfil the needs of mass production of micro components in different fields. A challenge of this technology lies in the downscaling of micro components, which leads to faster solidification of the polymeric material and a narrower process window. Moreover, the small cavity dimensions represent a limit for process monitoring due to the inability to install in-cavity sensors. Therefore, new solutions must be found. In this study, the downscaling effect was investigated by means of three spiral geometries with different cross sections, considering the achievable flow length as a response variable. Process indicators, called “process fingerprints”, were defined to monitor the process in-line. In the first stage, a relationship between the achievable flow length and the process parameters, as well as between the process fingerprints and the process parameters, was established. Subsequently, a correlation analysis was carried out to find the process indicators that are mostly related to the achievable flow length.

Hybrid-Light-Source Stereolithography for Fabricating Macro-Objects With Micro-Textures

2021 ◽  
Author(s):  
Wenxuan Jia ◽  
Yuen-Shan Leung ◽  
Huachao Mao ◽  
Han Xu ◽  
Chi Zhou ◽  
...  
Keyword(s):  
Light Source ◽  
Dimensional Accuracy ◽  
Beam Width ◽  
Surface Structures ◽  
Light Sources ◽  
Scanning Method ◽  
Hardware System ◽  
Building Area ◽  
Micro Features ◽  
Display Resolution

Abstract Microscale surface structures are commonly found on macroscale bodies of natural creatures for their unique functions. However, it is difficult to fabricate such multi-scale geometry with conventional stereolithography processes that rely on either laser or digital micromirror device (DMD). More specifically, the DMD-based mask projection method displays the image of a cross-section of the part on the resin to fabricate the entire layer efficiently; however, its display resolution is limited by the building area. In comparison, the laser-based vector scanning method builds smooth features using a focused laser beam with desired beam-width resolution; however, it has less throughput for its sequential nature. In this paper, we studied the hybrid-light-source stereolithography process that integrates both optical light sources to facilitate the fabrication of macro-objects with microscale surface structures (called micro-textures in the paper). The hardware system uses a novel calibration approach that ensures pixel-level dimensional accuracy across the two light sources. The software system enables designing the distribution and density of specific microscale textures on a macro-object by generating projection images and laser toolpaths for the two integrated light sources. Several test cases were fabricated to demonstrate the capability of the developed process. A large fabrication area (76.8 mm × 80.0 mm) with 50 μm micro-features can be achieved with a high throughput.

Ad astra: Graphic Signalling in the Acrostic Hymn of Nebuchadnezzar II (BM 55469)

2021 ◽  
Vol 48 (2) ◽  
pp. 318-326
Author(s):  
Martina Schmidl
Keyword(s):  
Writing System ◽  
Structural Elements ◽  
Micro Features

Abstract This article examines two orthographic features in the Acrostic Hymn of Nebuchadnezzar II. It aims to show that the text makes use of the possibilities of the cuneiform writing system to create various levels of meaning. The first example clarifies structure and content with regard to a difficult passage in the fourth and last stanza of the text, in which a possible change of actors is indicated by an orthographic feature. The second example shows how orthography is used in the first stanza of the text to augment its message. These examples demonstrate how structural elements and micro-features such as orthography were used creatively to enhance the message of the hymn.

The Downsizing Effects in EDM Drilling of Micro Holes

2013 ◽  
Vol 549 ◽  
pp. 503-510 ◽  
Author(s):  
Gianluca D'Urso ◽  
Giancarlo Maccarini ◽  
C. Merla
Keyword(s):  
Electrical Discharge Machining ◽  
Steel Plates ◽  
Drilling Process ◽  
Micro Edm ◽  
Micro Electrical Discharge Machining ◽  
Micro Holes ◽  
Micro Drilling ◽  
Micro Features ◽  
Electron Microscopes ◽  
Manufacturing Technologies

The recent miniaturization trend in manufacturing, has enhanced the production of new and highly sophisticated systems in various industrial fields. In recent years, machining of the so called difficult to cut materials has become an important issue in several sectors. Micro Electrical Discharge Machining (micro-EDM) thanks to its contactless nature, is one of the most important technologies for the machining of this type of materials and it can be considered as one of the most promising manufacturing technologies for the fabrication of micro components. One of the most relevant applications of micro-EDM is micro-drilling. Micro holes in fact, are widely used for example in micro-electromechanical systems (MEMS), serving as channels or nozzles to connect two micro-features, and in micro-mechanical components. The present study is about micro drilling of metal plates by means of micro-EDM technology. In particular, the aim of this work is to investigate the effects of the downsizing of the micro holes diameter on the drilling performances. The influence of the reduction of the diameters in terms of both process performances (e.g., tool wear, taper rate, diametrical overcut) and general quality of the holes was investigated. Steel plates having thickness equal to 0.8 mm were taken into account. The drilling process was carried out using a micro-EDM machine Sarix SX 200 with carbide electrodes having diameter equal to 300, 200, 100 and 50 μm. Since the standard electrodes adopted in this study had a diameter equal to 300 μm, a wire EDM unit was used to obtain the other electrodes. The relationship between the process parameters considered the most significant and the final output, was studied. Furthermore, the geometrical and dimensional properties of the micro-holes were analyzed using both optical and scanning electron microscopes. In particular, it is demonstrated that the diameter size has a significant influence on the final value of the diametrical overcut while peak current and frequency parameters have a negligible effect.

scholarly journals Age Related Variation in Feminine Handwriting among Population Groups of Delhi, India

2018 ◽  
Vol 6 (1) ◽  
pp. 1-6
Author(s):  
Vijit Deepani ◽  
A.K Kapoor ◽  
Monika Saini
Keyword(s):  
Significant Variation ◽  
Research Result ◽  
Age Groups ◽  
Population Group ◽  
Population Groups ◽  
Related Variation ◽  
Age Related ◽  
Significant Difference ◽  
Micro Features ◽  
Lower Loop

Background: Handwriting is a uniquely human trait which progresses and evolves during lifetime and declines with age. The aim of the present paper is to assess variation in handwriting features with age among female writers of select population groups of Delhi, India (for roman script). Method: A total of 405 handwritten samples were obtained from female (n=405) writers in the age range of 14-60 years. Writers were stratified into three age groups (≤ 18 years, 19-38 years and ≥39 years) in accordance to population group. Macro- and micro-features of handwriting were extracted from the scanned handwritten samples. These features were subjected to statistical analysis in the objective driven research. Result: The mean difference among age groups for pen pressure, height of handwriting and handwriting connectivity was statistically significant (p < 0.001). Significant difference was also observed among age groups for all micro-features of handwriting selected in the present study, namely, nature of ‘i’ – dot (p < 0.001), nature of lower loop of ‘g’ (p < 0.01); nature of‘d’- stem (p < 0.01), nature of ‘m’-hump (p < 0.05) and ‘r’- shape (p < 0.001). Conclusion: The present study showed that there was a significant variation in both macro- and micro- features of handwriting with respect to age of the writer. Pen pressure, height of handwriting and handwriting connectivity were prominent macro-features that addressed age related variation in handwriting. In addition, significant variation was observed among age groups for all micro-features of handwriting selected in the present study. The present study has immense forensic significance as it can assist to analyze age of the writer on the basis of handwriting characteristics.

scholarly journals Bourdieu and Genette in Paratext: How Sociology Counts in Linguistic Reasoning

2018 ◽  
Author(s):  
Hisham M. Ali
Keyword(s):  
Social Life ◽  
Interactive Approach ◽  
Theory Of Practice ◽  
Structure And Agency ◽  
The Earth ◽  
Micro Features

While Bourdieu’s theory of practice provides an ensemble of conceptual tools, which analyze patterns of social life that are irreducible to the limiting view of individuals as free-acting agents, Genette’s paratextual theory offers the metalanguage necessary to account for the microcosm of paratext as a linguistic space. This study takes issue with unidirectional approaches to researching paratexts in terms of linguistic or sociological accounts, and argues for a bidirectional understanding of paratext to unearth the interplay between structure and agency. Drawing on Genette’s paratextual features and Bourdieu’s sociology, this interactive approach is explored in a series of analyses of paratexts enveloping two Arabic translations of Gibran’s The Earth Gods. Through a discussion of the linguistic manifestations and the socio-historical backdrops of paratexts, the paper argues that the preface with its attendant micro features has the potential to exhibit the translation illusion, which epistemologically foregrounds the stakes and investments that motivate the production of translation.

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